WO2024217186A1 - Projection screen and manufacturing method therefor, and projection system - Google Patents

Abstract

Provided in the embodiments of the present application are a projection screen and a manufacturing method therefor, and a projection system. The projection screen comprises: a surface functional layer, a Fresnel lens layer and a reflecting layer, wherein the Fresnel lens layer comprises a plurality of lens units, and the reflecting layer is at least located on lens surfaces of the lens units. The projection screen provided in the embodiments of the present application can achieve effects such as improving the black luminance of the projection screen by absorbing incident ambient light, increasing the contrast of a projected image by selectively reflecting incident projection light while absorbing light of other wavebands, and improving the gain uniformity of the projection screen.

Description

Projection screen, method for making same and projection system

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application filed with the State Intellectual Property Office of China on April 19, 2023, with application number 202310422256.0 and application name “Projection screen, its manufacturing method and projection system”, all of which are incorporated by reference into this application; this application claims the priority of the Chinese patent application filed with the State Intellectual Property Office of China on May 16, 2023, with application number 202310548405.8 and application name “A projection screen and projection system”, all of which are incorporated by reference into this application Please refer to the following: This application claims the priority of the Chinese patent application filed with the State Intellectual Property Office of China on August 25, 2023, with application number 202311078929.1 and application name “Projection screen and projection system”, all of which are incorporated by reference into this application; This application claims the priority of the Chinese patent application filed with the State Intellectual Property Office of China on November 2, 2023, with application number 202311449292.2 and application name “A method for making a projection screen”, all of which are incorporated by reference into this application.

Technical Field

The present application relates to the field of projection technology, and in particular to a projection screen, a manufacturing method thereof, and a projection system.

Background Art

As display products continue to grow in size, the market for projection display products as large-screen products that replace LCD and organic electroluminescent (EL) TVs is rapidly expanding in consideration of power consumption, weight, and size. Laser TVs that use ultra-short-throw projection equipment are developing rapidly because of their high image quality and large screen convenience.

The current projection system can usually be used in conjunction with a projection screen. The projection device emits projection light, which is incident on the projection screen and then reflected by the projection screen to the human eye, where the projected image is viewed. A Fresnel lens layer is provided inside the projection screen to reflect the projection light emitted by the projection device toward the audience.

Summary of the invention

According to a first aspect of an embodiment of the present application, a projection screen is provided, comprising:

Surface functional layer;

A Fresnel lens layer is located on one side of the surface functional layer; the Fresnel lens layer includes a plurality of lens units, the plurality of lens units are arranged in concentric circles that expand in sequence along the radial direction; the lens unit includes a lens surface that is tilted relative to the plane where the surface functional layer is located; and

A reflective layer, at least covering the inclined surface of the lens unit;

The inclination angle of the lens surface of each lens unit is sufficient to reflect the light emitted by the projection device to the reflective layer on the lens surface toward the viewer;

The lens units are axially symmetrically distributed, the symmetry axis of each lens unit is perpendicular to the horizontal direction, and the center of the lens unit is located on the straight line where the symmetry axis is located; the inclination angle of the lens surface of at least one lens unit in the multiple groups of lens units at the first position is greater than the inclination angle at the second position, and the distance from the first position to the symmetry axis is greater than the distance from the second position to the symmetry axis.

According to a second aspect of the present application, a projection system is provided, comprising:

A projection device for emitting projection light; and

A projection screen, located at the light-emitting side of the projection device, the projection screen being the above-mentioned projection screen;

Wherein, the projection device is an ultra-short-throw laser projection device; the projection device comprises:

A three-color laser light source device, used for emitting three-primary-color lasers;

a light modulation component, located at the light output side of the three-color laser light source device, and used to modulate the output laser light of the three-color laser light source device; and

The projection lens is located at the light-emitting side of the light modulation component.

According to a third aspect of an embodiment of the present application, a method for manufacturing a projection screen is provided, comprising:

Fresnel lens layer manufacturing process: manufacturing a Fresnel lens layer; a surface of one side of the Fresnel lens layer has a plurality of lens units, each of the lens units is in the shape of concentric circles that are sequentially expanded and arranged along the radial direction; the lens unit includes a lens surface and a non-lens surface that are connected to each other;

Wavelength selective reflection layer manufacturing process: forming a wavelength selective reflection layer on the surface of the lens unit; the thickness of the wavelength selective reflection layer along the plane perpendicular to the projection screen increases as the radius of each lens unit increases; and

A surface functional layer manufacturing step: forming a surface functional layer on one surface of the Fresnel lens layer having the wavelength selective reflection layer.

According to a fourth aspect of the embodiments of the present application, a method for manufacturing a projection screen is provided, comprising:

A Fresnel lens layer is manufactured; a surface of one side of the Fresnel lens layer has a plurality of arc-shaped lens units, and the arc-shaped lens units are concentrically arranged; each of the lens units comprises a lens surface and a non-lens surface connected to each other, the lens surface is inclined relative to the plane where the projection screen is located, and the non-lens surface is used to connect the lens surface;

A vapor deposition source is arranged at a set position of the Fresnel lens layer to form a reflective layer on the lens surface of the plurality of lens units; the vapor deposition source is located on one side of the Fresnel lens layer having the plurality of lens units, and a set distance is provided between the vapor deposition source and the plurality of lens units;

A surface functional layer is formed on a side of the Fresnel lens layer facing away from the reflective layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a projection system provided in an embodiment of the present application;

FIG2 is a schematic diagram of a cross-sectional structure of a projection screen in the related art;

FIG3 is one of the schematic diagrams of projection effects provided in an embodiment of the present application;

FIG4 is a schematic diagram of partitions of a projection screen provided in an embodiment of the present application;

FIG5 is one of the schematic cross-sectional structure diagrams of a projection screen provided in an embodiment of the present application;

FIG6 is one of the schematic diagrams of the planar structure of the Fresnel lens layer provided in an embodiment of the present application;

FIG7 is a second schematic diagram of the projection effect provided in an embodiment of the present application;

FIG8 is one of the curves showing the variation of the inclination angle of the inclined surface of the Fresnel structure at different positions provided by an embodiment of the present application;

FIG9 is a schematic diagram of a cross-sectional structure of the projection screen along the symmetry axis I-I' in FIG6;

FIG. 10 is a second curve showing the variation of the inclination angle of the inclined surface of the Fresnel structure at different positions provided by an embodiment of the present application;

FIG11 is a second schematic diagram of the cross-sectional structure of a projection screen provided in an embodiment of the present application;

FIG12 is a third schematic diagram of the cross-sectional structure of the projection screen provided in an embodiment of the present application;

FIG13 is a fourth schematic diagram of the cross-sectional structure of the projection screen provided in an embodiment of the present application;

FIG14 is a schematic diagram of a planar structure of a surface functional layer provided in an embodiment of the present application;

FIG15 is a fifth schematic diagram of the cross-sectional structure of a projection screen provided in an embodiment of the present application;

FIG16 is a sixth schematic diagram of the cross-sectional structure of a projection screen provided in an embodiment of the present invention;

FIG17 is a seventh schematic diagram of the cross-sectional structure of a projection screen provided in an embodiment of the present invention;

FIG18 is an eighth schematic diagram of the cross-sectional structure of a projection screen provided in an embodiment of the present invention;

FIG19 is a ninth schematic diagram of the cross-sectional structure of a projection screen provided in an embodiment of the present application;

FIG20 is a tenth schematic diagram of the cross-sectional structure of a projection screen provided in an embodiment of the present application;

FIG21 is a schematic diagram of a structure of a wavelength selective reflection layer provided in an embodiment of the present application;

FIG22 is a second schematic diagram of the structure of the wavelength selective reflection layer provided in an embodiment of the present application;

FIG23 is a third schematic diagram of the structure of the wavelength selective reflection layer provided in an embodiment of the present application;

FIG24 is a reflectivity curve of the wavelength selective reflection layer provided in an embodiment of the present application to light of different wavelength bands;

FIG25 is a schematic diagram of the optical path of the projection light incident on the projection screen provided by an embodiment of the present application;

FIG26 is one of the schematic diagrams of coating provided in an embodiment of the present application;

FIG27 is a reflectivity curve of a wavelength-selective reflection layer produced by a wavelength shift according to an embodiment of the present application;

FIG28 is a second schematic diagram of coating provided in an embodiment of the present application;

FIG29 is a curve showing changes in optical parameters of a metal complete oxide provided in an embodiment of the present application;

FIG30 is a curve showing changes in optical parameters of metal suboxides provided in an embodiment of the present application;

FIG31 is a curve showing the change of oxidation number with the flow rate of reactive gas in the reactive sputtering process of plasma luminescence control provided in an embodiment of the present application;

FIG32 is a curve showing the change of oxygen partial pressure with the flow rate of reactive gas in the reactive sputtering process of plasma luminescence control provided in an embodiment of the present application;

FIG33 is a curve showing the variation of the extinction coefficient with the reactive gas flow rate in the reactive sputtering process of plasma luminescence control provided in an embodiment of the present application;

FIG34 is a curve showing the change of film forming speed with the change of reactive gas flow rate in the reactive sputtering process controlled by plasma luminescence provided in an embodiment of the present application;

FIG35 is a schematic diagram of the structure of a projection device provided in an embodiment of the present application;

FIG36 is a flowchart of a method for manufacturing a projection screen according to an embodiment of the present application;

37 is a schematic structural diagram of a film-forming cathode portion of a sputtering device in the related art;

FIG38 is a schematic structural diagram of a film-forming cathode portion of a sputtering device provided in an embodiment of the present application;

FIG39 is a schematic diagram of a sputtering process provided in an embodiment of the present application;

FIG40 is a second schematic diagram of the planar structure of the Fresnel lens layer provided in an embodiment of the present application;

Fig. 41 is a schematic diagram of the cross-sectional structure along the A-A' direction in Fig. 40;

FIG42 is a second flowchart of the method for manufacturing a projection screen provided in an embodiment of the present application;

FIG43 is a schematic cross-sectional structure diagram of the positional relationship between the evaporation source and the Fresnel lens layer provided in an embodiment of the present application;

FIG44 is a schematic diagram of a planar structure of the positional relationship between the evaporation source and the Fresnel lens layer provided in an embodiment of the present application;

FIG45 is a second schematic plan view of the positional relationship between the evaporation source and the Fresnel lens layer provided in an embodiment of the present application;

Fig. 46 is a schematic diagram of the cross-sectional structure along the I-I' direction in Fig. 44;

FIG47 is a schematic cross-sectional view showing the positional relationship between the evaporation source, the baffle and the Fresnel lens layer provided in an embodiment of the present application;

FIG48 is a schematic plan view of the positional relationship between the baffle and the Fresnel lens layer provided in an embodiment of the present application;

FIG49 is a second cross-sectional structural schematic diagram of the positional relationship among the evaporation source, the baffle and the Fresnel lens layer provided in an embodiment of the present application;

FIG50 is a schematic diagram of a planar structure of the positional relationship among an evaporation source, a baffle and a Fresnel lens layer provided in an embodiment of the present application;

FIG51 is a second schematic plan view of the positional relationship among the evaporation source, the baffle and the Fresnel lens layer provided in an embodiment of the present application;

FIG52 is a third cross-sectional structural schematic diagram of the positional relationship among the evaporation source, the baffle and the Fresnel lens layer provided in an embodiment of the present application;

Fig. 53 is a schematic diagram of the cross-sectional structure along the B-B' direction in Fig. 40;

FIG54 is a schematic diagram showing the positional relationship among the evaporation source, the baffle and the Fresnel lens layer along the cross section shown in FIG53 ;

FIG55 is a third schematic diagram of the planar structure of the evaporation source, the baffle and the Fresnel lens layer provided in an embodiment of the present application;

FIG56 is a fourth schematic diagram of the planar structure of the evaporation source, the baffle and the Fresnel lens layer provided in an embodiment of the present application;

Figure 57 is a schematic diagram of the planar structure of the evaporation source, baffle and lens structure layer provided in an embodiment of the present application.

DETAILED DESCRIPTION

In order to make the features and advantages of the present application more obvious and easy to understand, the present application will be further described below in conjunction with the drawings and examples. However, the example embodiments can be implemented in various forms and should not be construed as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present application more comprehensive and complete, and to fully convey the concepts of the example embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and thus their repeated descriptions will be omitted. The words expressing position and direction described in this application are all explained using the drawings as examples, but changes may be made as needed, and all changes are included in the scope of protection of this application. The drawings of this application are only used to illustrate the relative position relationship and do not represent the true proportions.

With the popularity of laser display products, the market for laser TVs has expanded rapidly as a large-screen product to replace LCD and organic EL TVs. In order to achieve better brightness and display effects, projection equipment is generally used with a projection screen.

FIG. 1 is a schematic diagram of the structure of a projection system provided in an embodiment of the present application.

As shown in FIG. 1 , the projection system includes: a projection device 2 and a projection screen 1 .

The projection screen 1 is located on the light emitting side of the projection device 2. The audience faces the projection screen 1. The projection device 2 emits projection light. The projection light is incident on the projection screen 1 and is emitted to the position of the audience through the projection screen 1, so that the audience can watch the projected image.

When the projection device 2 and the audience are located on the same side of the projection screen 1, the projection system is a front projection system. When the projection device 2 and the audience are located on both sides of the projection screen 1, the projection system is a rear projection system. In the front projection system, the projection device 2 emits projection light to the projection screen 1, and the projection screen 1 reflects the projection light to the audience, so that the audience can see the projected image. In the rear projection system, the projection device 2 emits projection light to the projection screen 1, and the projection light is emitted to the audience through the projection screen 1, so that the audience can see the projected image.

The ultra-short-throw projection device has the characteristics of short projection distance and large projection screen, and is very suitable for application in the home field. The projection system provided in the embodiment of the present application can adopt the ultra-short-throw projection device. The embodiment of the present application takes the front-projection ultra-short-throw projection system as an example to specifically illustrate the structure of the projection screen. The front-projection ultra-short-throw projection system usually installs the projection screen 1 on the wall or hangs it at a high place. The projection device 2 is located below the projection screen 1, and the projection light is emitted from the bottom of the projection screen 1 to the projection screen 1 obliquely upward. Since the ultra-short-throw projection system has a small projection ratio, a larger-sized projection image can be obtained while reducing the distance between the projection device 2 and the projection screen 1, which is very suitable for application in scenes such as laser TVs.

FIG. 2 is one of the structural schematic diagrams of a projection screen in the related art.

As shown in FIG2 , the projection screen includes: a surface layer 10, a Fresnel lens layer 12 and a reflective layer 13, wherein the surface layer 10 and the Fresnel lens layer 12 are bonded to each other via an adhesive layer 14, and the Fresnel lens layer 12 includes a plurality of lens units, each of which is in the shape of concentric circles that expand in sequence along the radial direction. The surface of the lens unit is provided with a reflective layer 13, and the lens unit can make the light L emitted by the projection device 1 enter the reflective layer 13 on the surface of the Fresnel lens layer 12 and then reflect toward the position where the audience is located, so that the projection light enters the human eye and the projection image is viewed.

FIG. 3 is one of the schematic diagrams of the projection effect provided in the embodiment of the present application.

For ease of explanation, only one lens unit 121 is shown in FIG3 . In actual applications, each lens unit 121 has the same problem. Since the lens unit 121 is usually a spherical mirror, that is, the same lens unit 121 is located on a spherical mirror with the same radius of curvature, and the spherical mirror itself has astigmatism, as shown in FIG3 , the lens unit 121 cannot reflect the incident light to the same position, and the light collection effect is poor, thereby causing the gain uniformity of the projection screen to deteriorate.

FIG. 4 is a schematic diagram of partitions of a projection screen provided in an embodiment of the present application.

As shown in FIG4 , the projection screen is usually placed on a wall or hung high up when in use. If the projection screen is rectangular, the projection The bottom edge of the screen is parallel to the horizontal direction, and the sides are parallel to the vertical direction, and the vertical direction is a direction perpendicular to the horizontal direction. When calculating the gain uniformity of the projection screen, the projection screen is evenly divided into three parts along the horizontal and vertical directions, thereby dividing the projection screen into 9 areas S1 to S9. The gain uniformity is measured by the ratio between the average gain of areas S1, S3, S7, and S9 and the gain of area S5. When the gain of area S5 is set to the maximum, the limit of the gain uniformity of the projection screen is about 70%.

FIG. 5 is one of the schematic cross-sectional structure diagrams of the projection screen provided in an embodiment of the present application.

As shown in FIG. 5 , the projection screen includes: a surface functional layer 11 , a Fresnel lens layer 12 and a reflective layer 13 .

The surface functional layer 11 can be located on the outermost surface of the projection screen. In the embodiment of the present application, the surface functional layer 11 is located on the side closest to the audience, thereby protecting the projection screen. In addition, the surface functional layer 11 can also be processed in a variety of ways according to different needs to achieve the effects of expanding the viewing angle, resisting ambient light reflection, and resisting ceiling reflection.

FIG. 6 is a schematic diagram of the planar structure of a Fresnel lens layer provided in an embodiment of the present application.

As shown in Figures 5 and 6, the Fresnel lens layer 12 is located on one side of the surface functional layer 11, specifically on the side of the surface functional layer 11 opposite to the audience. The Fresnel lens layer 12 includes a plurality of lens units 121 arranged according to a set rule.

According to different application scenarios and manufacturing processes, the lens unit 121 can adopt different structures. As shown in FIG6 , multiple groups of lens units 121 are arranged in concentric circles that expand in sequence along the radial direction. When the projection screen is applied to an ultra-short-focus projection system, the center O of the concentric lens unit 121 is usually not located in the projection screen, and the projection screen does not contain a complete lens unit, but contains a partial arc of the lens unit. When the projection device emits projection light from the bottom side of the projection screen to the projection screen, the center of the lens unit 121 can be located outside the projection screen and close to the bottom side, then the radius of each lens unit 121 gradually increases as it gradually moves away from the bottom side.

As shown in FIG5 , the lens unit 121 includes a lens surface x1 and a non-lens surface x2 connected to each other. The lens surface x1 is tilted relative to the surface functional layer 11, and the tilt angle of the lens surface x1 is set according to the incident angle of the projection light, so as to reflect the outgoing light of the projection device toward the audience when it is incident on the reflective layer on its surface. The non-lens surface x2 is used to connect the lens surface x1.

The reflective layer 13 at least covers the lens surface of each lens unit 121 of the Fresnel lens layer 12. The lens surface of the lens unit has a specific tilt angle, so that the reflective layer 13 covering its surface also has a corresponding tilt angle, thereby allowing the projection light to be incident on the reflective layer 13 on the surface of the lens unit and reflected toward the position of the audience by the reflective layer 13.

In some embodiments, the reflective layer 13 can be a metal film formed by evaporation or sputtering process, and the metal film covers the surface of the lens unit 121, so that the surface of the metal film has the same undulation trend as the lens unit, and the surface of the metal film can maintain the reflection angle of the lens unit facing the incident light when designed. The metal film can be made of aluminum, silver, titanium and other metals, which are not limited here. When the structure shown in Figure 5 is adopted, when the reflective layer 13 is located on the back of the projection screen, aluminum paste or silver paste can also be applied.

As shown in FIG6 , the projection screen is usually rectangular and includes four sides, and the adjacent sides are perpendicular to each other. When in use, the projection screen is usually set on a wall or hung at a high place, and the bottom side and the top side are usually parallel to the horizontal direction x, and the sides are perpendicular to the horizontal direction. In the embodiment of the present application, the projection screen is an axisymmetric figure, and its symmetry axis I-I' is perpendicular to the bottom side, and each lens unit 121 is axially symmetrically distributed about the symmetry axis I-I', and the center of each lens unit is located on the symmetry axis I-I'.

In the embodiment of the present application, the inclination angle of the lens surface x1 of at least one lens unit 121 at the first position is greater than the inclination angle at the second position, wherein the distance from the first position to the symmetry axis I-I' is greater than the distance from the second position to the symmetry axis I-I', then the inclination angle of the lens surface of the lens unit 121 can satisfy: it increases with the increase of the vertical distance from the lens surface x1 to the symmetry axis I-I'. As shown in FIG6 , each lens unit 121 can be divided into two parts, left and right, along the symmetry axis I-I', wherein the inclination angle of the lens surface x1 of the lens unit on the left side gradually increases along the first direction xl, and the inclination angle of the lens surface x1 of the lens unit on the right side gradually increases along the second direction xr. The inclination angles of the lens surfaces of the same lens unit are mutually symmetrical about the symmetry axis I-I', that is, in the same lens unit 121, the inclination angles of the lens surfaces at positions where the vertical distances from the left and right sides to the symmetry axis I-I' are equal are equal, that is, in the same lens unit 121, the inclination angles of the lens surfaces at positions that are mutually symmetrical about the symmetry axis I-I' are equal.

FIG. 7 is a second schematic diagram of the projection effect provided in an embodiment of the present application.

In the embodiment of the present application, the tilt angle of the lens surface of at least one lens unit is set to increase as the vertical distance from the lens surface to the symmetry axis I-I' increases, that is, the tilt angles of the lens surfaces at both sides of the same lens unit are larger, as shown in FIG7, so that the light incident on both sides can be concentrated more toward the middle position. By comparing FIG4 and FIG7, it can be seen that through the above-mentioned setting of the present application, the light collection effect of the lens unit can be optimized, thereby improving the gain uniformity of the projection screen.

Based on the above principle, in order to concentrate more light at the edge of the projection screen to the central position and improve the gain uniformity of the projection screen, the embodiment of the present application sets all lens units in the projection screen so that the inclination angle of the lens surface increases with the increase of the vertical distance from the lens surface to the symmetry axis I-I' of the projection screen, thereby concentrating the light to the middle position to the greatest extent.

As shown in Figure 6, if the intersection positions of the lens unit 121 and the bottom side of the projection screen are A and D, the intersection point of the bottom side and the symmetry axis I-I' is C, and the intersection point of the upper side of the projection screen and the symmetry axis I-I' is B, then the inclination angle of the lens surface at each position of the lens unit satisfies the rule shown in Figure 8. Figure 8 is one of the change curves of the inclination angle of the lens surface of the lens unit at different positions provided in an embodiment of the present application. It can be seen from Figure 8 that the change in the inclination angle of the lens surface of the same lens unit satisfies the sine function. From position A to position B and then to position D, the inclination angle of the lens surface of the lens unit first gradually decreases and then gradually increases, changing in a sinusoidal curve.

For a lens unit 121, the A/D position is the position of the lens unit close to the edges of both sides of the projection screen, and the B position is the middle position of the lens unit. In order for the lens unit to focus the light from both sides to the middle position, the inclination angle of the lens surface of the lens unit at the positions on both sides needs to be larger than the inclination angle at the middle position, so that after the light enters the lens unit, more light is reflected to the middle position, achieving the effect of focusing light to the middle.

FIG9 is a schematic diagram of the cross-sectional structure of the projection screen along the symmetry axis I-I’ in FIG6 .

As shown in FIG9 , the projection device usually emits a projection light L toward the projection screen at the middle position below the projection screen. Since the position of the projection device is fixed, the incident angle and direction of the projection light L when incident on different positions of the projection screen are different. In order to make the projection light be reflected toward the position where the audience is located, each lens unit needs to be designed into a concentric circle shape that expands sequentially along the radial direction, and the inclination angle of the lens surface x1 of each lens unit along the same radial direction is different. In the embodiment of the present application, the inclination angle of the lens surface of each lens unit increases along the radial direction as the radius of the lens unit increases.

Taking FIG9 as an example, the tilt angle of the lens surface of the same lens unit varies at different positions (such as positions A, B, and D), so the tilt angles of the lens surfaces of the lens units along different directions are not comparable, but along the same direction, such as the radial direction y in FIG9, the radius of each lens unit increases successively, and the tilt angle of the lens surface x1 of each lens unit increases successively, that is, the tilt angle of the lens surface x1 of each lens unit along the radial direction y satisfies: θ1<θ2<θ3. The position of the lens unit with a larger radius is closer to the edge of the projection screen. In order to allow the projection light incident on the lens unit to be reflected to the middle position, the tilt angle of the lens surface of the lens unit closer to the edge position needs to be set larger, so the tilt angle of the lens surface of the lens unit needs to be set to increase along the radial direction with the increase of the radius.

FIG. 10 is a second variation curve of the tilt angle of the lens surface of the lens unit at different positions provided by an embodiment of the present application.

As shown in FIG10 , the variation law of the inclination angle of the lens surface of each lens unit satisfies the sine function. The larger the radius of the lens unit, the larger the range occupied by the plane where the projection screen is located. Therefore, the more drastic the change of the inclination angle of the lens surface of the lens unit from the edge position to the middle position, the greater the amplitude of the sine curve that it satisfies. Then according to the above law, the amplitude of the sine function satisfied by the inclination angle of the lens surface of each lens unit in the embodiment of the present application increases with the increase of the radius of the lens unit. Taking FIG10 as an example, the sine curve f1 represents the variation law of the inclination angle of the lens surface of the lens unit with a larger radius, and the sine curve f2 represents the variation law of the inclination angle of the lens surface of the lens unit with a smaller radius. It can be seen from FIG10 that the amplitude of the sine curve f1 satisfied by the inclination angle of the lens surface of the lens unit with a larger radius is greater than the amplitude of the sine curve f2 satisfied by the inclination angle of the lens surface of the lens unit with a smaller radius.

In some embodiments, the projection screen can be used with an ultra-short-throw projection device. The ultra-short-throw projection system can project large-size images. According to the current projection screen size, the radius of the lens unit is within 2000 mm, and the change in the tilt angle of the lens surface of the same lens unit (m in FIG. 10 ) is greater than 0 and less than or equal to 2.25°. As the radius of the lens unit increases, the change in the tilt angle of its lens surface gradually increases. After experimental verification, the change in the tilt angle of the lens surface of the lens unit increases with the increase in the size of the projection screen. When the radius of the lens unit is within 2000 mm, the maximum variation of the inclination angle of the lens surface of the same Fresnel structure does not exceed 2.25°.

It is worth noting that the embodiment of the present application only takes the case where the radius of the lens unit in the projection screen is within 2000 mm as an example. When the size of the projection screen is further increased so that the radius of the lens unit exceeds 2000 mm, the change in the inclination angle of the lens surface of the lens unit may exceed 2.25°. The embodiment of the present application does not limit the specific value of the change.

FIG. 11 is a second schematic diagram of the structure of the projection screen provided in an embodiment of the present application.

As shown in Fig. 5 and Fig. 11, the projection screen further includes: an adhesive layer 14, which is located between the surface functional layer 11 and the Fresnel lens layer 12 and is used to bond the surface functional layer 11 to the Fresnel lens layer 12. The adhesive layer 14 can be made of an acrylic or silicone adhesive, or a UV curable resin material, which is not limited here.

In some embodiments, as shown in FIG. 5 , the lens unit 121 of the Fresnel lens layer 12 is located on the side away from the surface functional layer 11 , and the adhesive layer 14 is used to bond the surface functional layer 11 to the surface of the Fresnel lens layer 12 opposite to the lens unit 121 .

In some embodiments, as shown in FIG. 11 , the lens unit 121 of the Fresnel lens layer 12 is located on the side facing the surface functional layer 11, and the adhesive layer 14 is used to bond the surface functional layer 11 to the reflective layer 13 on the surface of the lens unit 121. When the lens unit 121 is disposed on the side close to the adhesive layer 14, the adhesive layer 14 can protect the reflective layer 13. At this time, since the Fresnel lens layer 12 is located on the side farthest from the audience, and no light is incident on the Fresnel lens layer 12, the requirements on the light transmittance and damage of the Fresnel lens layer 12 are reduced, and it is no longer necessary to use expensive optical materials to make the Fresnel lens layer 12, and cheaper industrial materials can be used for production, thereby reducing production costs.

In some embodiments, as shown in Figure 11, the Fresnel lens layer 12 includes a first substrate 122, the surface of the first substrate 122 facing the surface functional layer 11 and the surface on the opposite side of the surface functional layer 11 are both flat surfaces, and the lens unit 121 is located on the first substrate 122.

Among them, the first substrate 122 can be made of materials such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), triacetylcellulose (TAC), cycloolefin polymer (COP), thermoplastic polyurethane (TPU), polyvinyl chloride (PVC), polyimide (PI), polyamide (PA), polyethylene (PE), and polypropylene (PP).

The lens unit 121 can be formed by applying ultraviolet curable resin to a mold having a lens unit shape, and UV curing the ultraviolet curable resin while imprinting it with the first substrate 122. In addition, the lens unit 121 can also be made of other materials combined with other manufacturing methods, which are not limited here.

FIG. 12 is a third schematic diagram of the structure of the projection screen provided in an embodiment of the present application.

In some embodiments, as shown in FIG12 , the Fresnel lens layer 12 is an integrated structure, one side surface of the Fresnel lens layer 12 is a lens unit 121, and the other side surface is a flat surface. The Fresnel lens layer 12 with an integrated structure can omit the process of combining the substrate with the lens unit, further simplifying the manufacturing process. The Fresnel lens layer 12 with an integrated molding structure can be manufactured by thermoforming, which is not limited here.

FIG13 is a fourth schematic diagram of the structure of the projection screen provided in an embodiment of the present application, and FIG14 is a schematic diagram of the planar structure of the surface functional layer provided in an embodiment of the present application.

In some embodiments, the surface functional layer 11 has a light diffusion function, as shown in FIG13 , the surface functional layer 11 may include: a second substrate 111 and a diffusion layer 112. The second substrate 111 serves as a substrate for the diffusion layer 112, the second substrate 111 is in contact with the adhesive layer 14, and the diffusion layer 112 is located on the surface of the second substrate 111 on the opposite side to the adhesive layer 14.

Current projection systems usually use laser light sources. Lasers have high collimation, so the divergence angle of the projection light is small. The light reflected by the projection screen has high collimation, which also leads to a small viewing angle. By setting the diffusion layer 112, the light passing through the diffusion layer can be The post-emission angles are diversified, so that the light finally emitted from the projection screen has a certain divergence angle, which increases the viewing angle of the audience viewing the projection image. In addition, the diffusion layer 112 is also beneficial to suppress the generation of laser speckle and optimize the projection image.

The diffusion layer 112 can be formed on the surface of the second substrate 111 by making the resin material contain diffusion particles. The diffusion particles can be, but are not limited to, silicon dioxide particles, aluminum oxide particles, titanium oxide particles, cerium oxide particles, zirconium oxide particles, tantalum oxide particles, zinc oxide particles, magnesium fluoride particles, etc.

The second substrate 111 may be made of, but is not limited to, PET, PEN, PC, PMMA, TAC, COP, TPU, PVC, PI, PA, PE, PP and other materials.

In some embodiments, the diffusion layer 112 may have anisotropic diffusion properties, where anisotropic diffusion means that the diffusion angles in different directions are different. As shown in FIG. 14 , the diffusion angle of the diffusion layer 112 along the horizontal direction x is greater than the diffusion angle along the vertical direction y. The horizontal direction x and the vertical direction y are different directions in the plane where the projection screen is located. The horizontal direction x is parallel to the bottom side of the projection screen; the vertical direction y is perpendicular to the horizontal direction and parallel to the symmetry axis I-I' of the projection screen. The vertical direction y corresponds to the height direction when the audience watches the projection screen. If the diffusion angle of the diffusion layer in the vertical direction is larger, the light from the ceiling will also be diffused, resulting in an increase in the black field brightness of the projection screen. If the diffusion angle of the diffusion layer in the horizontal direction is large, the field of view angle of the projection screen in the left and right directions can be diffused. Therefore, by applying the anisotropy that the diffusion angle of the diffusion layer in the horizontal direction x is greater than the diffusion angle of the diffusion layer in the vertical direction y, the field of view angle of the projection screen in the horizontal direction can be increased while avoiding an increase in the black field brightness.

In a specific implementation, by manufacturing the diffusion layer into a structure in which the ridges are arranged along the vertical direction y, it is possible to achieve an effect that the diffusion angle in the horizontal direction x is greater than the diffusion angle in the vertical direction y.

As shown in FIG4 , in the related art, when the inclination angle of the lens surface of the same lens unit is constant, the lens unit is a spherical mirror, which will produce astigmatism, so the areas S1, S4 and S7 of the projection screen, and the areas S3, S6 and S9 will emit light to both sides in the horizontal direction, so the gain uniformity of the projection screen deteriorates. When an anisotropic diffusion layer whose diffusion angle in the vertical direction y is smaller than the diffusion angle in the horizontal direction x is used, the gain uniformity of the projection screen will further decrease due to the increase in the diffusion degree in the horizontal direction. If the inclination angle of the lens surface of the lens unit is increased to suppress the diffusion of light in the horizontal direction, the light in the areas S2 and S5 of the projection screen will be emitted downward, thereby causing the front brightness of the projection screen to decrease. Therefore, in order to overcome the above problems, the diffusion angle of the diffusion layer in the vertical direction y is increased, so that the light can be further diffused from the bottom to the top, thereby improving the gain uniformity of the projection screen. As mentioned above, the increase in the diffusion angle of the diffusion layer in the vertical direction y will cause the black field brightness to increase, which will still affect the display effect.

In the embodiment of the present application, the inclination angle of the lens surface of the lens unit is set so that the inclination angle at the edge position is greater than the inclination angle at the middle position, so that the light can be concentrated more at the middle position, and at the same time, an anisotropic diffusion layer is used in which the diffusion angle in the horizontal direction x is greater than the diffusion angle in the vertical direction y, so that the black field brightness can be reduced while suppressing the brightness reduction of the projection screen in areas S2 and S5.

The embodiment of the present application also tests the gain uniformity of the projection screen made according to the above concept. The specific production process is: an 80-inch lens unit is made on the surface of a 250μm thick PET substrate to form a Fresnel lens layer. Then, a reflective layer is formed on the surface of the lens unit by evaporating aluminum. Next, a diffusion layer with a diffusion angle in the vertical direction smaller than the diffusion angle in the horizontal direction is made on the surface of a 250μm thick PET substrate. The above two PET substrates are bonded to each other by a transparent adhesive to obtain a projection screen.

As shown in Fig. 4, the same method is used to measure the gain uniformity of the projection screen by the ratio between the average gain of regions S1, S3, S7, and S9 and the gain of region S5. By setting the inclination angle of the lens surface of the lens unit in the projection screen so that the inclination angle at the two side positions is greater than the inclination angle at the middle position, the gain uniformity of the projection screen can be improved to more than 80%, and the gain uniformity of the projection screen can be achieved to 100% by designing a reasonable inclination angle.

FIG. 15 is a fifth schematic diagram of the cross-sectional structure of the projection screen provided in an embodiment of the present application.

In some embodiments, as shown in FIG. 15 , the surface functional layer 11 only includes a second substrate 111, which is in contact with the adhesive layer 14 and is bonded to the Fresnel lens layer 12 via the adhesive layer 14. The material of the second substrate 111 includes a diffusion material, so when the second substrate 111 is formed, the second substrate 111 can have a light diffusion capability and a certain haze. The second substrate 111 including the diffusion material can expand the field of view angle, It can also reduce the reflection of light, thereby preventing the light from forming a clear image on the ceiling. It has the effect of anti-ceiling reflection and can enhance the audience's viewing experience.

FIG. 16 is a sixth schematic diagram of the cross-sectional structure of the projection screen provided in an embodiment of the present invention.

In some embodiments, as shown in FIG16 , the surface functional layer 11 includes only a second substrate 111, which is in contact with the adhesive layer 14 and is bonded to the Fresnel lens layer 12 through the adhesive layer 14. The surface of the second substrate 111 on the opposite side of the adhesive layer 14 is an uneven surface. The uneven surface can be formed by sandblasting or alkali treating the surface of the second substrate 111, which is not limited here. The uneven surface of the second substrate 111 can play a certain role in light diffusion and atomization, thereby expanding the viewing angle, resisting ceiling reflection, and the like.

FIG. 17 is the seventh schematic diagram of the cross-sectional structure of the projection screen provided in the embodiment of the present invention, and FIG. 18 is the eighth schematic diagram of the cross-sectional structure of the projection screen provided in the embodiment of the present invention.

In some embodiments, as shown in FIGS. 17 and 18 , the projection screen may also include only the Fresnel lens layer 12, the reflective layer 13 and the surface functional layer 11. The lens unit 121 of the Fresnel lens layer 12 is arranged on the side facing the viewer, the reflective layer 13 is located on the surface of the lens unit 121, and the surface functional layer 11 is located on the surface of the reflective layer 13. At this time, the surface functional layer adopts a diffusion layer 112 covering the reflective layer 13. The diffusion layer 112 can be formed on the surface of the reflective layer 13 by coating, spraying, etc. The projection screen structure shown in FIGS. 17 and 18 can effectively reduce the thickness of the projection screen. The Fresnel lens layer 12 can adopt the structure shown in FIG. 17 , including a first substrate 122 and a lens unit 122 located on the first substrate 122, or can adopt the integrated structure shown in FIG. 18 .

FIG. 19 is a ninth schematic diagram of the cross-sectional structure of the projection screen provided in an embodiment of the present application.

In some embodiments, as shown in FIG19 , the adhesive layer 14 may contain a light absorbing material and color the adhesive layer 14 to improve the black brightness of the projection screen. In some embodiments, the adhesive layer 14 may be colored with a dark material such as carbon black or dye to deepen the color of the adhesive layer 14, which is not limited here.

As shown in FIG2 , the projection light L emitted by the projection device is incident on the inside of the projection screen, and is reflected by the reflective layer 13 after being incident on the reflective layer 13, and then is emitted from the projection screen in the direction of the audience. At the same time, the ambient light C can also be incident on the inside of the projection screen. Similarly, some ambient light will also be reflected when incident on the reflective layer 13 and will be emitted from the projection screen. These reflected ambient lights will interfere with the projection light, thereby reducing the contrast of the projected image.

In order to overcome the above problems, in the related art, the film layer in the projection screen is usually colored, so that the colored film layer can absorb the incident ambient light and reduce the reflection of the ambient light.

As shown in FIG19 , the adhesive layer 14 can be colored, and dyes, carbon black and other light-absorbing substances can be mixed into the material of the adhesive layer 14, so that the ambient light is absorbed when it enters the adhesive layer 14. However, since the colored film layer in the projection screen absorbs light of all wavelengths, the projection light L has a reduced emission efficiency after entering the colored film layer (such as the adhesive layer 14), and cannot improve the contrast.

In order to improve the contrast of the projected image, as shown in FIG. 20 , in some embodiments, the reflective layer may adopt a wavelength selective reflective layer F, which can selectively reflect the projection light emitted by the projection device, while greatly reducing the reflectivity of light in other bands. When the projection device is turned off, a black appearance can be achieved, and when the projection device is turned on, a bright display can be obtained, thereby significantly improving the contrast of the projected image.

As shown in FIG20 , the projection light L emitted by the projection device is incident on the inside of the projection screen from the side of the surface functional layer 11, and is reflected by the wavelength selective reflection layer F on the surface of the lens unit 121 when incident on the lens unit 121, thereby reflecting in the direction of the audience. At the same time, the ambient light C is incident on the inside of the projection screen from the side of the surface functional layer 11. When the ambient light C is incident on the wavelength selective reflection layer F on the surface of the lens unit, since the wavelength selective reflection layer F only reflects the projection light, the reflectivity of the ambient light in other wavelength bands is low, so the reflection of the ambient light can be greatly reduced, and the contrast of the projection light can be improved.

Specifically, the wavelength selective reflection layer F uses the principle of the resonance cavity to select the wavelength of the light emitted toward the audience, while other wavelengths are restricted in the resonance cavity and cannot be emitted, thereby achieving the effect of selective reflection of the projection light.

Figure 21 is one of the structural schematic diagrams of the wavelength selective reflection layer provided in an embodiment of the present application; Figure 22 is a second structural schematic diagram of the wavelength selective reflection layer provided in an embodiment of the present application; Figure 23 is a third structural schematic diagram of the wavelength selective reflection layer provided in an embodiment of the present application.

As shown in FIG. 21 and FIG. 22 , the wavelength selective reflection layer F includes: a reflective layer 131 and at least one film layer group z located on the reflective layer 131 . The film layer groups z are stacked and each film layer group z includes: a semi-transparent layer 132 and a transparent medium layer 133 .

The reflective layer 131 has the function of reflecting light. The reflective layer 131 is located on the side away from the audience and does not need to transmit light. Therefore, it can be made of a material with reflective properties but no light-transmitting properties. In some embodiments, the reflective layer 131 can be made of materials such as aluminum, aluminum alloy, silver or silver alloy. For example, the reflective layer 131 can be made of aluminum alloys such as Al and AlSi, or a laminated structure composed of silver alloys such as Ag and AgPaCu, which is not limited here. The reflective layer 131 can be made by sputtering, evaporation and other methods, which is not limited here.

For each film layer group z, the semi-transparent layer 132 is located on the side close to the surface functional layer 11, the reflective layer 131 is located on the side of the semi-transparent layer 131 opposite to the surface functional layer 11, and there is a certain distance between the semi-transparent layer 132 and the reflective layer 131. The transparent medium layer 133 is located between the semi-transparent layer 132 and the reflective layer 131. The reflective layer 131, the semi-transparent layer 132 and the transparent medium layer 133 form a resonant cavity structure.

In some embodiments, the wavelength selective reflective layer F can be set to a single resonance structure as shown in FIG. 21, that is, the reflective layer 131, the semi-transparent layer 132 and the transparent medium layer 133 form a resonance structure; or the wavelength selective reflective layer F can be set to a double resonance structure as shown in FIG. 22, that is, the reflective layer 131, the semi-transparent layer 132 and the transparent medium layer 133 form a resonance structure, and the adjacent semi-transparent layer 132, the transparent medium layer 133 and the semi-transparent layer 132 form another resonance structure; and so on, the wavelength selective reflective layer F can also include more than two resonance structures. The more resonance structures included in the wavelength selective reflective layer F, the more precise its wavelength selectivity, and the cost will also increase accordingly. Therefore, it is necessary to strike a balance between performance and cost.

Specifically, the semi-transparent layer 132 in the wavelength selective reflection layer F has a semi-transparent and semi-reflective property, so that when the projection light is incident on the projection screen, the projection light can be incident on the resonance structure, and when the projection light oscillates and strengthens in the resonance structure, it can also be emitted from one side of the semi-transparent layer 132. In some embodiments, the semi-transparent layer 132 can be a laminated structure formed by at least one metal selected from Al, Nb, Ag and Ti, etc., which is not limited here. The semi-transparent layer 132 can be manufactured by sputtering, evaporation and other methods, which are not limited here.

The thickness of the transparent medium layer 133 determines the cavity length of the resonance structure, and the product of the refractive index and thickness of the transparent medium layer 133 determines the wavelength of the light emitted from the resonance structure to the audience and the wavelength that is extinguished inside the resonance structure. Therefore, when designing the resonance structure, it is necessary to select a dielectric material whose product of the refractive index and thickness satisfies the conditions for the projection light emitted by the projection device to resonate. In some embodiments, the transparent medium layer 133 can be made of materials such as metal oxides, nitrides or transparent resins. For example, the transparent medium layer 133 can be made of metal oxides or nitrides such as TiO2, Nb2O5, ZrO2, Al2O3, ZnO2, SiO2, etc., and can be made by reactive sputtering, electron beam (EB) evaporation, chemical vapor deposition and other methods; or it can also be made of a laminated structure of one or more of transparent resins such as PMMA, PC, PS, etc., and made by wet processing processes such as gravure printing and die coating, which are not limited here.

In some embodiments, as shown in FIG23 , the wavelength selective reflection layer F may further include a substrate 134, and the substrate 134 is located on the side of the semi-transparent layer 132 opposite to the transparent medium layer 133. The substrate 134 serves as the base of the resonance cavity and has a supporting and bearing function. In a specific implementation, the substrate 134 may be made of materials such as PET, which is not limited here.

In the embodiment of the present application, the projection light source can adopt a three-color laser light source device, which can emit red laser, green laser and blue laser. Then, by adjusting the refractive index and thickness of the material of the transparent medium layer, the resonance cavity can simultaneously enhance the reflection of red laser, green laser and blue laser, while attenuating the reflection of light in other bands, thereby improving the contrast of the projection light.

FIG24 is a reflectivity curve of the wavelength selective reflection layer provided in the embodiment of the present application for light of different wavelength bands. The position of the dotted line in FIG24 is the position of the peak wavelength of the three-color laser emitted by the three-color laser light source device. As can be seen from FIG24, the wavelength selective reflection layer can have a high reflectivity at the wavelengths of the red laser, green laser and blue laser emitted by the projection device at the same time, while the reflectivity at other wavelength bands is significantly reduced, which is conducive to improving the contrast of the projection light.

According to simulation tests, when the thickness of the semi-transparent layer 132 is within the range of 2nm to 20nm, the thickness of the reflective layer 131 is greater than 50nm and less than The effect is better when the product of the thickness of the light-transmitting medium layer 133 and the refractive index is in the range of 1200 to 1800.

It is worth noting that the thickness of the reflective layer 131, the semi-transparent layer 132 and the transparent medium layer 133 in the wavelength selective reflection layer F mainly focuses on the thickness of the film layer located on the lens surface x1 of the lens unit 121, and the thickness refers to the thickness of the film layer along the lens surface x1 perpendicular to the lens unit 121. This is because when designing the wavelength selective reflection layer F, the materials of each film layer in the wavelength selective reflection layer and the cavity length of the resonance cavity are selected and designed based on the incident angle range of the incident light on the lens surface x1 being ±15°. The thickness and refractive index of the transparent medium layer 133 in the wavelength selective reflection layer F along the direction perpendicular to the lens surface x1 are related to the wavelength of selective reflection, so the coating thickness of the transparent medium layer 133 needs to be accurately controlled.

Taking the example that the reflective layer 131 , the semi-transparent layer 132 and the transparent medium layer 133 in the wavelength selective reflective layer F are all manufactured by the coating process, the structure of each film layer in the embodiment of the present application is specifically described.

FIG. 25 is a schematic diagram of the optical path of the projection light incident on the projection screen provided in an embodiment of the present application.

As shown in FIG25, when the projection device is located below the bottom of the projection screen, the incident angles of the projection light emitted by the projection device when incident on different positions of the projection screen are also different. In order to make more projection light focus on the position where it is located, as shown in FIG25, the inclination angles of the lens surface x1 of each lens unit 121 are different. Taking the Fresnel lens layer 12 shown in FIG25 as an example, along the direction gradually away from the projection device 2 (away from the bottom side of the projection screen), the radius of each lens unit 121 increases successively, and the inclination angle of the lens surface x1 of each lens unit 121 gradually increases, that is, θ3<θ2<θ1. After reasonable design, when the angle of the projection light incident on the projection screen is 65° to 85°, the incident angle range of the projection light incident on the lens surface x1 of different lens units is within the range of 10° to 15°.

FIG. 26 is one of the schematic diagrams of coating provided in an embodiment of the present application.

In the related art, as shown in (a) in FIG. 26 , the coating process is usually a process of depositing a thin film on a flat surface 12’, and the film forming direction is perpendicular to the flat surface 12’ as shown in the direction of the arrow in FIG. 26 , that is, the thickness of the thin film 133’ at each position on the flat surface 12’ perpendicular to the flat surface 12’ is basically the same.

However, as shown in (b) of FIG. 26 , in the embodiment of the present application, it is necessary to coat the surface of the lens units 121 in a concentric circle shape. Then, when the light-transmitting medium layer 133 is formed by the same coating process, the obtained film layer is still uniform in thickness in the film-forming direction, that is, the thickness L of the light-transmitting medium layer 133 on each lens unit 121 along the plane perpendicular to the projection screen (parallel to the film-forming direction in FIG. 26 ) is equal. However, the inclination angles of the lens surfaces x1 of each lens unit 121 are different, so the thicknesses of the light-transmitting medium layers 133 on the surfaces of different lens units along the plane perpendicular to the lens surface x1 are not equal.

For the sake of convenience, the thickness of the film layer parallel to the film forming direction is referred to as the plane thickness, and the thickness of the film layer perpendicular to the lens surface of the lens unit is referred to as the vertical thickness. According to the relationship shown in FIG26, the vertical thickness of the light-transmitting medium layer 133 is L×cosθ, where θ is the inclination angle of the lens surface x1 of the lens unit 121. Taking FIG26 as an example, the vertical thickness of the light-transmitting medium layer 133 on different lens units 121 from the bottom to the top of the projection screen satisfies: L3＝L×cosθ3, L2＝L×cosθ2, L1＝L×cosθ1; and the inclination angle of the lens surface x1 of each lens unit increases with the increase of the radius of the lens unit, that is, θ1>θ2>θ3, then according to the above relationship, it can be known that: L1<L2<L3.

FIG. 27 is a reflectivity curve of the wavelength shift produced by the wavelength selective reflection layer provided in an embodiment of the present application.

Comparing FIG. 24 and FIG. 27 , when the light-transmitting medium layer 133 is made of Nb 2 O 5 , when the thickness of the light-transmitting medium layer 133 increases by 10%, the wavelength selectively reflected by the wavelength selective reflection layer will shift toward the long-wave direction.

It can be seen that when the wavelength selective reflection layer F is manufactured by the existing coating process, the thickness of the light-transmitting medium layer along the lens surface perpendicular to the lens unit decreases as the radius of the lens unit increases. This will cause the color near the bottom of the screen to be reddish when the projection screen displays a full white image, and the color uniformity of the screen is reduced.

In view of this, when manufacturing the wavelength selective reflection layer F in the projection screen, the coating equipment is adjusted in the embodiment of the present application so that the wavelength selective reflection layer F covering the lens surface x1 of each lens unit 121, especially the thickness of the light-transmitting medium layer 133 in the wavelength selective reflection layer F along the direction perpendicular to the lens surface x1, can be equal, thereby improving the chromaticity uniformity of the projection screen.

FIG. 28 is a second schematic diagram of coating provided in an embodiment of the present application.

When manufacturing the wavelength selective reflection layer F, especially the transparent medium layer 133, the thickness of the film layer can be controlled in the film forming direction, so that the thickness of the film layer in the wavelength selective reflection layer F along the plane perpendicular to the projection screen increases with the increase of the radius of the lens unit, thereby ensuring that the thickness of the film layer along the plane perpendicular to the lens surface x1 on each lens unit 121 is equal or approximately equal. Taking FIG. 28 as an example, the thickness of the transparent medium layer 133 along the plane perpendicular to the lens surface x1 on different lens units 121 from the bottom to the top of the projection screen (i.e., the above-mentioned vertical thickness) satisfies: L3 = L2 = L1, and the thickness of the transparent medium layer 133 along the plane perpendicular to the projection screen (i.e., the above-mentioned plane thickness) satisfies: L3'<L2'<L1'.

It should be noted that when the reflective layer adopts the wavelength selective reflective layer F, the manufacturing order of each film layer in the wavelength selective reflective layer F is different according to the setting direction of the Fresnel lens layer 12. In some embodiments, as shown in FIG20, when the lens unit 121 of the Fresnel lens layer 12 is located on the side away from the adhesive layer 14, it is necessary to form a semi-transmissive layer, a light-transmissive medium layer and a reflective layer on the lens unit 121 in sequence. In some embodiments, as shown in FIG11, when the lens unit 121 of the Fresnel lens layer 12 is arranged facing the adhesive layer 14, it is necessary to form a reflective layer, a light-transmissive medium layer and a semi-transmissive layer on the lens unit 121 in sequence, which is opposite to the above manufacturing order.

As shown in FIG20 , the projection light L emitted by the projection device is incident on the inside of the projection screen from the side of the surface functional layer 11, and is reflected by the reflective layer 13 on the surface of the lens unit when incident on the lens unit 121, thereby reflecting in the direction where the audience is located. Generally, the projection screen including the reflective layer 13 is a reflective screen, and the film layers before the light is incident on the reflective layer 13 are all light-transmissive.

In some embodiments, at least one of the light-transmitting film layers of the projection screen may contain a low-valent oxide, thereby reducing the transmittance of the light-transmitting film layer to the visible light band, that is, the low-valent oxide has a certain absorptivity to the visible light band. Therefore, when displaying a black image, it can absorb the incident ambient light and improve the black brightness of the projection screen.

Suboxides are incomplete oxides. In some embodiments, metal suboxides can be used, and the transmittance to the visible light band can be changed by controlling the oxygen content of the metal suboxides. Metal suboxides are transition products of metals during the oxidation process. Metals are mostly opaque substances. From the metallic state to the oxide state after complete oxidation, the transmittance to the visible light band will gradually increase, and the absorptivity will gradually decrease. Finally, it will be completely oxidized into an oxide that is transparent to the visible light band. In the embodiments of the present application, the oxide formed by the completely oxidized metal is called the metal complete oxide, and the oxide formed by the incompletely oxidized metal is called the metal suboxide.

The following is a detailed introduction to the changes in optical parameters during metal oxidation. FIG29 is a curve showing the changes in optical parameters of a metal complete oxide provided in an embodiment of the present application; FIG30 is a curve showing the changes in optical parameters of a metal low-valent oxide provided in an embodiment of the present application.

Generally, optical parameters include parameters that characterize various aspects of performance. The main parameters that need to be considered in the projection screen are the refractive index n and the extinction coefficient k. Among them, the extinction coefficient k determines the absorption capacity of the incident visible light band. The larger the extinction coefficient, the stronger the absorption capacity. Comparing Figures 29 and 30, it can be seen that the refractive index n of the metal complete oxide decreases with the increase of wavelength and then tends to be constant, and the extinction coefficient k decreases rapidly with the increase of wavelength, and the value in the visible light band is 0, that is, it has no light absorption in the visible light band. For metal low-valent oxides, the refractive index n will tend to decrease first and then increase with the increase of wavelength, and the extinction coefficient k will tend to decrease first, then increase and then decrease with the increase of wavelength, and the value of the extinction coefficient k in the visible light band is above 0, so it has an absorption effect on the visible light band. Therefore, by adding a metal low-valent oxide to any one of the light-transmitting film layers in the projection screen, the film layer can have certain light absorption properties in the visible light band while being light-transmitting.

In specific implementation, metal suboxides can be produced by a reactive sputtering process with plasma luminescence control. In the sputtering chamber, the sputtering source is metal. In addition to using discharge gases such as argon, reactive gases such as oxygen are also needed. The plasma luminescence intensity is adjusted by controlling the flow rate of the reactive gas to form metal suboxides. There is a transition state in the process from the metallic state to the fully oxidized metal oxide, and metal suboxides can be formed in the transition zone.

Specifically, FIG. 31 is a curve showing the change of oxidation number with the change of reactive gas flow rate in the reactive sputtering process of plasma luminescence control provided in the embodiment of the present application; FIG. 32 is a curve showing the change of oxygen partial pressure with the change of reactive gas flow rate in the reactive sputtering process of plasma luminescence control provided in the embodiment of the present application; FIG. 33 is a curve showing the change of extinction coefficient with the change of reactive gas flow rate in the reactive sputtering process of plasma luminescence control provided in the embodiment of the present application. Wherein, the sputtering source is metal, and the reactive gas is oxygen. During the sputtering process, the metal will gradually be oxidized and gradually converted from the metallic state to the metal complete oxide state. The solid circle frames in FIG. 31 to FIG. 33 are the metal low-valent oxide states. The dotted circle represents the metal's complete oxide state.

As shown in Figures 31 and 32, as the flow rate of the reactive gas gradually increases, the main component of the substance formed in the metal zone is metal, and the oxidation number and oxygen partial pressure tend to increase slowly; when it reaches the transition zone, the metal is partially oxidized, and the main component is metal low-valent oxide, and the oxidation number and oxygen partial pressure increase significantly; and when it reaches the oxide zone, the metal is completely oxidized into metal complete oxide, and the oxidation number and oxygen partial pressure show a trend of slowly increasing, and after the flow rate of the reactive gas increases to a certain extent, the oxidation number and oxygen partial pressure tend to stabilize.

As shown in Figure 33, as the reactive gas flow rate gradually increases, the main component of the substance formed in the metal zone is still metal, so the extinction coefficient is large, the light absorption is strong and the light transmittance is poor; as the reactive gas flow rate gradually increases, the metal is gradually oxidized, and when the metal is oxidized into a metal low-valent oxide in the transition zone, its extinction coefficient is greatly reduced, but it still has a certain light absorption and the light transmittance increases; as the reactive gas flow rate increases to a certain extent, the metal is completely oxidized to form a metal complete oxide, at which time the extinction coefficient is reduced to the minimum value and it no longer has light absorption.

It can be seen that by controlling the oxygen content of metal suboxides, their extinction coefficients can be changed, so that the metal suboxides have different degrees of absorption of visible light.

In order to improve the contrast of the projected image, the reflective layer 13 can adopt a wavelength selective reflective layer F. Based on the above analysis, a low-valent oxide can be used in the wavelength selective reflective layer F to make it have both wavelength selective reflectivity and absorption of incident light, thereby improving the performance of the projection screen.

As described above, the product of the refractive index and thickness of the light-transmitting medium layer 133 in the wavelength-selective reflection layer F determines the wavelength selected for reflection by the wavelength-selective reflection layer. In some embodiments, the light-transmitting medium layer 133 may be made of metal complete oxides such as TiO2, Nb2O5, ZrO2, Al2O3, ZnO2, SiO2, etc. However, these metal complete oxides are transparent to light in the visible light band. In order to make the wavelength-selective reflection layer F have both wavelength-selective reflectivity and absorptivity, the light-transmitting medium layer 133 may contain low-valent oxides. As described above, the light-transmitting medium layer 133 may be made of metal low-valent oxides, or metal low-valent oxides may be added to the material of the light-transmitting medium layer 133, and the transparency of the metal low-valent oxides may be reduced to a certain extent by controlling the oxygen content of the metal low-valent oxides.

In this way, the wavelength selective reflection layer F can have both wavelength selective reflection and certain light absorption in the visible light band, which can shield the ambient light. There is no need to set a separate light absorption layer in the projection screen, which simplifies the structure of the projection screen and reduces the production cost.

In some embodiments, the material of the light-transmitting medium layer 133 in the wavelength-selective reflection layer F may be entirely low-valent oxides.

In some embodiments, the material of the light-transmitting medium layer 133 in the wavelength-selective reflective layer F may include low-valent oxides and complete oxides. For example, the low-valent oxides and complete oxides may be layered.

In some embodiments, the light-transmitting dielectric layer 133 may include a first dielectric layer and a second dielectric layer stacked in layers; wherein the first dielectric layer may be made of a low-valent oxide, and the second dielectric layer may be made of a complete oxide; or, the first dielectric layer may be made of a complete oxide, and the second dielectric layer may be made of a low-valent oxide. The order of the low-valent oxide and the complete oxide is not limited.

Each film layer in the wavelength selective reflection layer F can be manufactured by a sputtering process. When the light-transmitting medium layer 133 is formed by sputtering, the metal is oxidized to different degrees by controlling the flow rate of the reactive gas, i.e., oxygen. When the metal is partially oxidized, a metal low-valent oxide is formed, and when the metal is completely oxidized, a metal complete oxide is formed. The absorption capacity of the film layer formed by reactive sputtering to the incident light decreases with the increase of the oxygen content. Therefore, in order to enable the light-transmitting medium layer 133 to achieve a suitable light absorption effect, the flow rate of the reactive gas needs to be finely controlled.

In a specific implementation, the metal low-valent oxide in the light-transmitting medium layer can be one of Nb2O5-x, TiO2-y or Ta2O5-z, wherein 0＜x＜5, 0＜y＜2, 0＜z＜5, and x, y, and z can be integers or decimals within the above ranges, which are not limited here. In addition to the above materials, other metal low-valent oxides can also be used, which are not listed here one by one.

FIG. 34 is a curve showing the change of film forming speed with the reactive gas flow rate in the reactive sputtering process controlled by plasma luminescence provided in an embodiment of the present application.

As shown in Figure 34, as the reactive gas flow rate gradually increases, the main component of the film layer in the metal area is still metal, so the film formation speed is The rate of film formation is relatively fast; as the reactive gas flow rate gradually increases, the metal is gradually oxidized, and the film formation rate decreases accordingly; as the reactive gas flow rate increases to a certain extent, the metal is completely oxidized to form metal complete oxide, and the film formation rate further decreases.

As can be seen from FIG34 , the film-forming speed of metal suboxides is faster than that of metal complete oxides. Therefore, if metal suboxides are used as the light-transmitting medium layer of the resonant structure, productivity can be improved, which is beneficial to reducing costs.

Based on the same concept, an embodiment of the present application further provides a projection system, as shown in FIG. 1 , the projection system includes: a projection device 2 and a projection screen 1 located on the light emitting side of the projection device 2 .

FIG. 35 is a schematic diagram of the structure of the projection device provided in an embodiment of the present application.

As shown in FIG35 , the projection device includes: a light source device 21, an illumination light path 22, a light modulation component 23, and a projection lens 24. The illumination light path 22 is located at the light exit side of the light source device 21, the light modulation component 23 is located at the light exit side of the illumination light path 22, and the projection lens 24 is located at the light exit side of the light modulation component 23.

The light source device 21 can adopt a laser light source device. The laser light source device can adopt a monochromatic laser or a laser that can emit lasers of multiple colors or multiple lasers that emit lasers of different colors. When the laser light source device adopts a monochromatic laser, the laser display device also needs to be provided with a color wheel, which is used for color conversion. The monochromatic laser cooperates with the color wheel to achieve the purpose of emitting primary color lights of different colors in sequence. When the laser light source device adopts a laser that can emit lasers of multiple colors, it is necessary to control the laser light source to emit lasers of different colors as primary color lights in sequence.

In the embodiment of the present application, the light source device may adopt a three-color laser light source device, which may be a laser that emits three primary color lasers, such as an MCL laser, etc.; it may also include a red laser, a green laser, and a blue laser that emit three primary color lasers respectively. The use of a three-color laser light source device is conducive to improving the color gamut of the projected image, has better color expression, and can accurately reproduce the input image.

The illumination optical path 22 is located at the light output side of the light source device 21. The illumination optical path 22 collimates the output light of the light source device 21 and allows the output light of the light source device 21 to be incident on the light modulation component 23 at a suitable angle. The illumination optical path 22 may include multiple lenses or lens groups, which are not limited here.

The light modulation component 23 is used to modulate the incident light. In some embodiments, the light modulation component 23 can use a digital micromirror (Digital Micromirror Device, DMD for short). The light modulation component 23 receives the incident light after total reflection by the total reflection prism P, modulates the incident light, and reflects the modulated light. After passing through the illumination light path 22, the light beam meets the illumination size and incident angle required by the DMD. The surface of the DMD includes many tiny reflectors, each of which can be driven to deflect individually. By controlling the deflection angle of the DMD, the brightness of the light incident on the projection lens 24 is controlled.

The projection lens 24 is used to image the output light of the light modulation component 23 , and the image is projected after being imaged by the projection lens 24 .

In the embodiment of the present application, the projection device 2 can use an ultra-short-throw projection device, that is, the projection lens 24 in the projection device uses an ultra-short-throw projection lens. The use of an ultra-short-throw projection device can greatly shorten the distance between the projection device 2 and the projection screen 1, and can achieve large-size image display while shortening the projection distance.

The projection screen is located on the light-emitting side of the projection lens in the projection device. The projection screen includes a surface functional layer, a Fresnel lens layer and a reflective layer. The projection screen can adopt any of the above-mentioned projection screens, which can absorb the incident ambient light, improve the black brightness of the projection screen, selectively reflect the incident projection light, and absorb light of other bands to improve the contrast of the projection image, and enhance the gain uniformity of the projection screen.

On the other hand, an embodiment of the present application provides a method for manufacturing a projection screen. FIG. 36 is one of the flow charts of the method for manufacturing a projection screen provided in an embodiment of the present application.

As shown in FIG. 36 , the method for manufacturing a projection screen includes:

S10, manufacturing a Fresnel lens layer;

S20, forming a wavelength selective reflection layer on the surface of the lens unit;

S30, forming a surface functional layer on one side surface of the Fresnel lens layer with the wavelength selective reflection layer.

In some embodiments, the Fresnel lens layer can be formed by a UV molding process. A UV curable resin can be coated on a mold having a lens unit shape on the surface, and then the UV curable resin is pressed against the substrate at a set pressure, and UV irradiation is performed from one side of the substrate to cure the UV curable resin. The UV curable resin is tightly bonded to the substrate while being cured, so that the shape of the lens unit of the mold is transferred to the substrate to form a Fresnel lens layer.

In some embodiments, the integrally formed Fresnel lens layer may also be manufactured by a thermoforming method, wherein a heated mold having a Fresnel structure is used to thermoform a thermoplastic material layer, thereby forming the Fresnel lens layer.

The Fresnel lens layer manufactured by the above method has a plurality of lens units on one side of the surface, and each lens unit can be arranged in a concentric circle in a radially expanding manner. Each lens unit includes a lens surface and a non-lens surface connected to each other, and the lens surface is inclined at an angle such that the projection light incident on the reflective layer on the lens surface is reflected toward the viewer.

The wavelength selective reflection layer can be manufactured by using a coating process such as sputtering or evaporation. Depending on the structure of the projection screen, the manufacturing order of each film layer in the wavelength selective reflection layer is also different. When the lens unit of the Fresnel lens layer is arranged facing the surface functional layer, the manufacturing order of the wavelength selective reflection layer is as follows: forming a reflective layer on the surface of the lens unit of the Fresnel lens layer; forming a light-transmitting medium layer on the surface of the reflective layer; forming a semi-transmitting layer on the surface of the light-transmitting medium layer. When the lens unit of the Fresnel lens layer is arranged away from the surface functional layer, the manufacturing order of the wavelength selective reflection layer is as follows: forming a semi-transmitting layer on the surface of the lens unit of the Fresnel lens layer; forming a light-transmitting medium layer on the surface of the semi-transmitting layer; forming a reflective layer on the surface of the light-transmitting medium layer.

When a sputtering process is used to produce a semi-transparent layer, a reflective layer and a transparent medium layer, especially when a transparent medium layer is produced, the sputtering equipment is adjusted in the embodiment of the present application so that the thickness of the film layer finally formed on the lens surface of the lens unit along the direction perpendicular to the plane where the projection screen is located increases with the increase of the radius of each concentric lens unit, while the thickness of the film layer on the lens surface of each lens unit along the direction perpendicular to the lens surface can be equal or approximately equal.

Figure 37 is a schematic diagram of the structure of the film-forming cathode part of the sputtering device in the related art, Figure 38 is a schematic diagram of the structure of the film-forming cathode part of the sputtering device provided in an embodiment of the present application, and Figure 39 is a schematic diagram of the sputtering process provided in an embodiment of the present application.

Among them, (a) in Figure 37 and Figure 38 represents the top view structure of the sputtering device, (b) represents the side view structure of the sputtering device, and (c) represents the film layer thickness at different positions.

As shown in (a) and (b) of FIG. 37 , in the related art, the plane and cross-section of the sputtering source N in the sputtering equipment are uniform structures, and the substrate to be coated is arranged above the sputtering source N. As shown in (c) of FIG. 37 , the thickness of the film layer formed at different positions on the substrate is also equal.

In order to adjust the thickness of the film layer, in an embodiment of the present application, as shown in Figure 38, a correction plate D is set above the sputtering source N, and the correction plate D includes a plurality of sub-correction plate pairs a. The sub-correction plate pair a includes two sub-correction plates, and a gap of a set distance is provided between the two sub-correction plates; each sub-correction plate pair a is arranged along the second direction y.

As shown in FIG39 , a flexible material may be used when manufacturing the Fresnel lens layer, so that the formed Fresnel lens layer can be rolled. When the film layer of the wavelength selective reflection layer is formed by sputtering, the Fresnel lens layer can be rolled so that the lens unit 121 of the Fresnel lens layer 12 is disposed facing the sputtering source N. During the sputtering process, the Fresnel lens layer 12 is rolled so that the Fresnel structure layer 12 moves above the sputtering source N along the first direction x.

As shown in FIG. 39 , the first direction x and the second direction y are perpendicular to each other, and the second direction y is perpendicular to the first side of the projection screen. The first side can be the side to which the centers of the concentric lens units are close. When the projection device is set at the bottom of the projection screen, the second direction y is perpendicular to the bottom side of the projection screen. The sub-correction plate pairs a in the embodiment of the present application are arranged along the second direction, and the gaps of the sub-correction plate pairs a increase with the increase of the radius of the concentric lens units. The film thickness of the sputtering source is greater at the position where the gap of the sub-correction plate pair a is larger, and the film thickness is smaller at the position where the gap of the sub-correction plate pair a is smaller. As a result, the thickness of the light-transmitting medium layer formed on the surface of the lens unit along the plane perpendicular to the projection screen can gradually increase from the bottom to the top of the projection screen. Then, the thickness of the light-transmitting medium layer on the reflection surface of each lens unit along the plane perpendicular to the reflection surface can be equal or approximately equal, so that the chromaticity uniformity of the projection screen is achieved. better.

In some embodiments, the gap width of each pair of sub-correction plates a can be set according to the tilt angle of the lens surface of the corresponding lens unit, but the width of the lens unit is usually tens of microns to hundreds of microns, so it is difficult to set the width of the pair of sub-correction plates a according to such a size. In the embodiment of the present application, one pair of sub-correction plates a can correspond to multiple lens units, and the gap width of the pair of sub-correction plates a can be set according to the average value of the tilt angles of the lens surfaces of the corresponding multiple lens units.

Finally, a surface functional layer is formed on one side of the Fresnel lens layer having the wavelength selective reflection layer. The surface functional layer can have the effects of expanding the viewing angle, resisting ambient light reflection, resisting ceiling reflection, etc. And the surface functional layer can be located on different sides of the Fresnel lens layer.

In some embodiments, the surface functional layer can be located on the side of the Fresnel lens layer away from the lens unit. In this case, the surface functional layer can include a substrate and a diffusion layer formed on the surface of the substrate. The projection screen is formed by bonding the substrate of the surface functional layer to the Fresnel lens layer. Alternatively, a substrate containing a diffusion material can be directly used as the surface functional layer and bonded to the Fresnel lens layer to form a projection screen. Alternatively, the surface of the substrate can be directly sandblasted to form the surface functional layer, and then the substrate and the Fresnel lens layer are bonded to form a projection screen. This is not limited here.

In some embodiments, the surface functional layer may also be located on the wavelength selective reflection layer on the surface of the lens unit. In this case, the surface functional layer may be manufactured by directly performing sandblasting on the wavelength selective reflection layer, which is not limited here.

As described above, when the projection system is applied to application scenarios such as laser TV, the projection device can adopt an ultra-short-throw projection device. As shown in FIG40, in the projection screen used with the ultra-short-throw projection device, the center O of the lens unit 121 is usually not located inside the projection screen, but in an area outside the projection screen. The side of the projection screen close to the center O is usually the bottom side of the screen, and the radius of each lens unit 121 gradually increases as it gradually moves away from the bottom side. If the side of the projection screen facing the audience is called the front side, and the side away from the audience is called the back side, then in some embodiments, each lens unit 121 is located on the back side of the projection screen. Arranging each lens structure on the back side of the projection screen can reduce the risk of contamination and damage caused by user contact and ensure the long-term reliability of the Fresnel lens layer.

The following will take the projection screen used with the ultra-short-throw projection device as an example to specifically describe the structure and manufacturing method of the projection screen. However, the manufacturing method of the projection screen provided in the embodiment of the present application is not limited to manufacturing the screen of the ultra-short-throw projection device. The manufacturing method can also manufacture screens of different types of projection devices such as short-throw and long-throw. In the specific implementation, only the relevant parameters need to be adaptively adjusted.

FIG41 is a schematic diagram of the cross-sectional structure along the A-A’ direction in FIG2 . The A-A’ direction coincides with the symmetry axis of the projection screen along the vertical direction. The projection screen provided in the embodiment of the present application is an axisymmetric structure, and its symmetry axis is parallel to the vertical direction. When in use, the projection screen is usually set on a wall or hung at a high place, and the bottom edge of the projection screen is parallel to the horizontal direction, then the vertical direction is a direction perpendicular to the horizontal direction, and the extension line of the symmetry axis of the projection screen along the vertical direction passes through the center O of the lens structure.

As shown in FIG41 , a Fresnel lens layer 12 is provided in the projection screen. The surface of the Fresnel lens layer 12 on one side facing away from the projection device includes a plurality of lens units 121. In the cross section along the A-A’ direction in FIG10 , the shape of each lens unit 121 is similar to a triangle. Each lens unit 121 includes a lens surface x1 and a non-lens surface x2 connected to each other. The lens surface x1 is inclined relative to the plane where the projection screen is located, and the non-lens surface x2 is used to connect the lens surface x1. The inclination angle of the lens surface x1 of each lens unit 121 is designed according to the incident angle of the projection light, and the inclination angle satisfies that the projection light L can be reflected in the direction of the audience when it is incident on the reflective layer 13 on the surface of the lens surface x1. In this way, more projection light can be reflected in the direction of the audience, while reducing the reflection of ambient light in the direction of the audience, thereby improving the brightness and contrast of the projection picture.

When making a reflective layer on the surface of the Fresnel lens, according to the original design, it is hoped that the reflective layer will be formed only on the lens surface x1 of the lens unit, and not on the non-lens surface x2. The reflective layer is usually made by evaporation or sputtering, but the current reflective layer manufacturing process will not only form a reflective layer on the lens surface x1 of the lens unit, but also on the non-lens surface x2, which will cause light to be reflected when it enters the non-lens surface x2, which is inconsistent with the original design.

In view of this, an embodiment of the present application provides a method for manufacturing a projection screen. FIG. 42 is a second flowchart of the method for manufacturing a projection screen provided in an embodiment of the present application.

As shown in FIG. 42 , the method for making a projection screen includes:

S10, manufacturing a Fresnel lens layer;

S20, setting an evaporation source at a set position of the Fresnel lens layer to form a reflective layer on lens surfaces of the plurality of lens units;

S30, forming a surface functional layer on a side of the Fresnel lens layer facing away from the reflective layer.

The embodiment of the present application takes the use of the evaporation process to make the reflective layer as an example for specific description. In addition to the evaporation process, the reflective layer can also be made by sputtering or similar processes. The reflective layer can be made of a metal material with reflective properties, such as aluminum, silver, titanium, etc. In addition, the reflective layer can also adopt a multi-layer structure, which can achieve selective reflection of the incident light, thereby further improving the contrast of the projected image.

By improving the structure and position of the evaporation source in the embodiment of the present application, the reflective layer can be formed only on the lens surface of the lens unit, avoiding the reflective layer from being formed on the non-lens surface of the lens unit. The production process of the projection screen is described in detail below.

The Fresnel lens layer 12 may include a substrate and a lens unit 121 located on the substrate, wherein the lens unit 121 may be manufactured by using a mold having a Fresnel lens and a UV molding process using an ultraviolet curing resin.

Before manufacturing the reflective layer 13 on the surface of the lens unit 121, it is necessary to design the structure and the location of the evaporation source, and the design can be in various forms.

Figure 43 is a schematic diagram of the cross-sectional structure of the positional relationship between the evaporation source and the Fresnel lens layer provided in an embodiment of the present application; Figure 44 is one of the schematic diagrams of the planar structure of the positional relationship between the evaporation source and the Fresnel lens layer provided in an embodiment of the present application; Figure 45 is a second schematic diagram of the planar structure of the positional relationship between the evaporation source and the Fresnel lens layer provided in an embodiment of the present application; and Figure 46 is a schematic diagram of the cross-sectional structure along the I-I’ direction in Figure 44.

As shown in FIG. 43 , the evaporation source W is disposed on a side of the Fresnel lens layer 12 having the lens unit 121 , and there is a certain distance between the evaporation source W and the lens unit 121 . The evaporation source radiates the evaporation material isotropically in a working state.

In some embodiments, as shown in Figures 44 and 45, at least one evaporation source W arranged in an arc shape may be used when manufacturing the reflective layer. As shown in Figure 44, the number of evaporation sources W may be one, and the size of the evaporation source W is relatively large, and the shape is a section of an arc; or, as shown in Figure 45, the number of evaporation sources W is multiple, the size of the evaporation source W is relatively small, and the evaporation sources W are arranged in a section of an arc.

The evaporation source will isotropically radiate the evaporation material when evaporating the reflective layer. The evaporation source W is arranged in an arc shape so that the orthographic projection of the center of the evaporation source W on the plane where the projection screen is located coincides with the center of the lens unit 121, so that the evaporation material can be relatively evenly formed on the lens unit 121.

In order to prevent the evaporation source W from forming the evaporation material on the non-lens surface x2 of the lens unit 121, when the radius of the evaporation source W arranged in an arc shape is larger than the radius of any lens unit 121 in the Fresnel lens layer, only the evaporation material emitted from the evaporation source W toward the side of the center O will be incident on the lens surface x1 of the lens unit 121, thereby preventing the evaporation material from being incident on the non-lens surface x2 of the lens unit 121.

44 and 45 illustrate an example in which the evaporation source W is arranged in the form of a circular arc. In a specific implementation, the evaporation source W can also be arranged in the form of multiple circular arcs. In this case, multiple evaporation sources are required. In some embodiments, the size of the evaporation source is relatively large, and the shape of each evaporation source is a circular arc. Multiple evaporation sources can be arranged in the form of multiple concentric circular arcs. In some embodiments, the size of each evaporation source is relatively small. These evaporation sources are arranged in multiple circular arcs, and each circular arc is formed by arranging multiple evaporation sources.

When the evaporation source is arranged in multiple arcs, each arc can be arranged concentrically, and the radius of each arc needs to be greater than the radius of any lens unit 121 in the Fresnel lens layer. According to this design idea, the minimum radius of the evaporation source arranged in an arc shape can be determined.

Specifically, as shown in FIG46, in the order of the radius of each lens unit 121 from small to large, the inclination angle of the non-lens surface of the m-th lens unit relative to the normal tm is _αm , and the inclination angle of the non-lens surface of the n-th lens unit relative to the normal tn is _αn . In the cross section shown in FIG46, the inclination angle of the line connecting the innermost point P of the evaporation source and the vertex of the m-th lens unit relative to the normal tm is _θm , and the inclination angle of the line connecting the evaporation source W and the vertex of the n-th lens unit relative to the normal tn is _θn ; the vertical distance from the plane including the innermost point P of the evaporation source to the vertex of the lens unit 121 is h, the distance from the innermost point P of the evaporation source to the normal tm passing through the vertex of the m-th lens unit is _Sm , and the distance from the innermost point P of the evaporation source to the normal tn passing through the vertex of the n-th lens unit is _Sn .

The normal lines _tm and _tn are normal lines of the plane where the projection screen is located. The normal lines t claimed in the embodiments of the present application are perpendicular to the plane where the projection screen is located. The Fresnel lens layer 12 shown in FIG46 includes a substrate, and the plane where the projection screen is located may be parallel to the plane where the substrate of the Fresnel lens layer 12 is located, so the plane where the projection screen is located claimed in the embodiment of the present application can refer to the plane where the Fresnel lens layer 12 is located in FIG46, and the normal line of the plane where the projection screen is located is referred to as the normal line hereinafter.

As shown in FIG44, from the perspective of the planar structural relationship, the evaporation source is arranged in an arc shape, and the center of the evaporation source arranged in an arc shape is coincident with the center of the arc lens unit in the orthographic projection on the plane where the projection screen is located, and the radius of the evaporation source arranged in an arc shape is greater than the radius of all the circular lens units. The evaporation source W usually radiates isotropically when emitting the evaporation material. When the side of the evaporation source W emitting the evaporation material is arranged opposite to the side of the Fresnel lens layer 12 having the lens unit 121, as shown in FIG44, only the evaporation material emitted from the innermost periphery of the evaporation source W can be incident on the lens unit 121. Then, in the cross section along the radial direction, as shown in FIG46, the innermost point P of the evaporation source refers to the point of the evaporation source closest to the center O in the cross section, that is, the rightmost point of the evaporation source in FIG46. It can be seen from Figure 46 that in the cross-section along any radial direction, the inclination angle of the evaporated material emitted from the innermost point P of the evaporation source relative to the normal when it is incident on the vertex of the lens unit is usually smaller than the inclination angle of the evaporated material emitted from other positions of the evaporation source relative to the normal when it is incident on the vertex of the same lens unit. Therefore, the minimum inclination angle formed by the line connecting the innermost point P of the evaporation source and the vertex of the lens unit 121 is taken into consideration.

As shown in FIG. 46 , the vertex of the lens unit 121 refers to an intersection of the lens surface x1 and the non-lens surface x2 of the lens unit 121 on the side close to the vapor deposition source W in any cross section.

According to the trigonometric function relationship:

In order to prevent the evaporation material emitted by the evaporation source W from being formed on the non-lens surface x2 of the Fresnel lens, α _m <θ _m needs to be satisfied for the m-th lens unit, and α _n <θ _n needs to be satisfied for the n-th lens unit. Then, when the evaporation source W satisfies the above relationship for each lens unit 121, the minimum radius R that the evaporation source W arranged in an arc shape should satisfy can be found.

FIG46 is a schematic diagram of using an arc-shaped evaporation source, and the cross section shown in FIG46 is a cross section along the symmetry axis II' direction of the projection screen. When more arc-shaped evaporation sources are used or the evaporation sources are arranged into multiple concentric arcs, the cross section of each arc along any radial direction satisfies:

Wherein, α _i represents the inclination angle of the non-lens surface of the i-th lens unit 121 in a cross section along any radial direction of the Fresnel lens layer relative to the normal of the plane where the projection screen is located, θ _i represents the inclination angle of the line connecting the innermost point of the evaporation source and the vertex of the i-th lens unit 121 in the cross section relative to the normal. _{S i} represents the distance from the innermost point of the evaporation source in the cross section to the normal passing through the vertex of the i-th lens unit, and h represents the distance from the plane including the innermost point of the evaporation source to the vertex of the lens unit 121.

The definitions of the normal line, the innermost point of the evaporation source in the cross section, and the vertex of the lens unit can refer to the above embodiments and will not be repeated here. Referring to Figure 46, the plane including the innermost point P of the evaporation source refers to the plane passing through point P and parallel to the plane where the projection screen is located.

The position of the evaporation source satisfies that the inclination angle of the line connecting the vertices of any lens unit with respect to the normal of the plane where the projection screen is located is greater than the inclination angle with respect to the non-lens surface of the lens unit. Therefore, when the evaporation source radiates the evaporation material to the Fresnel lens layer, the evaporation material can be prevented from being incident on the non-lens surface of each lens unit.

In some embodiments, the lens surface x1 of each lens unit 121 in the Fresnel lens layer 12 is relative to the plane where the projection screen is located. The tilt angle and the tilt angle of the non-lens surface x2 of each lens unit 121 relative to the normal of the plane where the projection screen is located may vary. Then the evaporation source needs to be set according to the actual situation.

Specifically, when the projection screen is used in an ultra-short-throw projection system, the projection device is usually located below the projection screen, and the projection light is emitted obliquely upward to the projection screen. If the projection light is to be reflected in the direction of the audience, the inclination angle of the lens surface x1 of each lens unit 121 in the Fresnel lens layer 12 relative to the plane where the projection screen is located satisfies: the inclination angle of the lens surface x1 increases with the increase of the radius of the lens unit. As shown in Figures 43 and 46, in the projection screen used in the ultra-short-throw projection system, the center O of the Fresnel lens is located outside the projection screen, and in the cross-sectional structure schematic diagrams shown in Figures 43 and 46, the farther from the center O, the greater the inclination angle of the lens surface x1 of the lens unit 121 relative to the plane where the projection screen is located.

For the non-lens surface x2 of each lens unit 121, its inclination angle relative to the normal line of the plane where the projection screen is located can change with the lens surface x1, or can remain unchanged.

In some embodiments, as shown in FIG43 , the non-lens surface x2 of each lens unit 121 has the same inclination angle relative to the normal line t of the plane where the projection screen is located. For example, the non-lens surface x1 of each lens unit 121 is perpendicular to the plane where the projection screen is located, that is, α _i = 0 in the above formula (1). Then the position of the evaporation source W arranged in an arc shape satisfies that in any cross section along the radial direction, the inclination angle of the connection between the innermost point of the evaporation source W and the vertex of any lens unit 121 in the cross section relative to the normal line of the plane where the projection screen is located is greater than 0, that is, θ _i > 0 in the above formula (1).

In some embodiments, as shown in FIG46 , the inclination angle of the non-lens surface x2 of each lens unit 121 relative to the normal t of the plane where the projection screen is located increases as the radius of the lens unit 121 increases, that is, α _n >α _m in the cross-sectional view shown in FIG46 . Then, when the evaporation source W is set for this situation, the maximum value of the inclination angles of the non-lens surface x2 in the Fresnel lens layer 12 relative to the normal of the plane where the projection screen is located is the inclination angle of the non-lens surface of the lens unit with the largest radius. Therefore, the evaporation source W satisfies that the inclination angle of the line connecting the innermost point of the evaporation source and the vertex of the lens unit with the largest radius relative to the normal in the cross section along any radial direction of the Fresnel lens layer is greater than the inclination angle of the non-lens surface of the lens unit with the largest radius relative to the normal, and the above normals are all normals to the plane where the projection screen is located.

In a specific implementation, the distance between the evaporation source and the Fresnel lens layer can be 100 mm to 1000 mm, the width of the evaporation source arranged in an arc shape can be 20 mm to 300 mm, and the spacing between two adjacent circular evaporation sources can be within 300 mm. For example, the vertical distance between the evaporation source and the Fresnel lens layer can be 300 mm, the width of the evaporation source arranged in an arc shape can be 100 mm, and the spacing between two adjacent circular evaporation sources can be 20 mm.

Figure 47 is one of the cross-sectional structural schematic diagrams of the positional relationship between the evaporation source, the baffle and the Fresnel lens layer provided in an embodiment of the present application; Figure 48 is a planar structural schematic diagram of the positional relationship between the baffle and the Fresnel lens layer provided in an embodiment of the present application; Figure 49 is a second cross-sectional structural schematic diagram of the positional relationship between the evaporation source, the baffle and the Fresnel lens layer provided in an embodiment of the present application; Figure 50 is one of the planar structural schematic diagrams of the positional relationship between the evaporation source, the baffle and the Fresnel lens layer provided in an embodiment of the present application; Figure 51 is a second planar structural schematic diagram of the positional relationship between the evaporation source, the baffle and the Fresnel lens layer provided in an embodiment of the present application.

In some embodiments, as shown in FIG. 47 , a vapor deposition source W may be disposed on one side of the Fresnel lens layer 12 having a plurality of lens units 121, so that a set distance exists between the vapor deposition source W and the plurality of lens units 121; and a plurality of spaced-apart baffles D’ may be disposed between the vapor deposition source W and the plurality of lens units 121, so that the baffles D’ block the vapor deposition material emitted from the vapor deposition source W from being formed on the non-lens surface x2 of the lens unit 121.

Specifically, a plurality of baffles D' are provided between the evaporation source W and the Fresnel lens layer 12, which can block the evaporation source W from emitting the evaporation material onto the non-lens surface x2 of the lens unit 121. Since the lens surface and the non-lens surface of the lens unit 121 may have different inclination angles, the baffle D' usually needs to be set at an inclination, and the inclination angles of the baffles at different positions may be different. The inclination angle of each baffle needs to be set according to the standard that the evaporation material emitted by the evaporation source near it is blocked by the baffle D' and is not formed on the non-lens surface x of the lens unit 121 at the corresponding position. In some embodiments, the width of the lens unit 121 is in the micrometer range, and the spacing distance of the baffles D' can be several micrometers. The solution of using the evaporation source W and the baffle D' to cooperate with each other can make the distance between the evaporation source W and the Fresnel lens layer 12 not too large, and can avoid the uneven evaporation caused by the long distance between the evaporation source W and the remote lens unit.

The evaporation source W can be arranged in an arc shape, and accordingly, the shape of the baffle D' is a part of a conical surface, as shown in FIG48, which is a planar structure of the baffle D', and the overall contour of the baffle D' in the planar structure is an arc shape. From the perspective of the three-dimensional structure, the orthographic projection of the vertex of the conical surface where the baffle D' is located on the plane where the projection screen is located coincides with the center of the lens unit 121.

In some embodiments, as shown in FIG. 47 , the evaporation source W may have a relatively large width. In this case, only one evaporation source W needs to be set up. The evaporation source W may correspond to a plurality of baffles D’, thereby reducing the number of evaporation sources W used.

In some embodiments, as shown in FIG. 49 , the evaporation source W may have a relatively small width and a plurality of evaporation sources. In this case, a baffle D 'may be provided between each two adjacent evaporation sources W, thereby enabling a more sophisticated design of the evaporation source and the baffle. In some embodiments, as shown in FIG. 50 and FIG. 51 , the evaporation source W may be provided in a plurality of arcs. Referring to FIG. 50 , the number of evaporation sources W may be multiple, each evaporation source W is in the shape of an arc, and each arc-shaped evaporation source W may be concentrically arranged. Alternatively, referring to FIG. 51 , the number of evaporation sources W may be multiple, and each evaporation source W is discretely arranged, and these evaporation sources W are dispersedly arranged into a plurality of concentrically arranged arcs, and each arc is formed by the arrangement of a plurality of evaporation sources.

In order to prevent the evaporated material from being formed on the non-lens surface x2 of each lens unit 121, the baffle D' has a certain inclination angle. The inclination angle satisfied by the baffle is specifically described below.

FIG52 is a third schematic diagram of the cross-sectional structure of the positional relationship between the evaporation source, the baffle and the Fresnel lens layer provided in an embodiment of the present application. FIG52 shows the cross-sectional structure along the I-I' direction in FIG50. As shown in FIG52, the inclination angle of the non-lens surface x2 of the lens unit 121 relative to the normal t of the plane where the projection screen is located is α. In the cross section shown in FIG52, the inclination angle of the line connecting the innermost point P of the evaporation source and the edge of the baffle D' corresponding thereto close to the Fresnel lens layer relative to the normal t is θ. In the cross section shown in FIG52, the vertical distance from the innermost point P of the evaporation source to the normal passing through the edge of the baffle D' close to the Fresnel layer is _S1 , and the distance from the plane including the innermost point of the evaporation source to the edge of the baffle D' close to the Fresnel lens layer is _h1 .

The definitions of the normal line, the innermost point of the evaporation source in the cross section, and the plane including the innermost point of the evaporation source may refer to the above embodiments and will not be repeated here.

According to the trigonometric function relationship:

Among them, the function of the baffle D’ is to block the evaporated material from being incident on the non-lens surface x2 of the lens unit 121, so the baffle is usually inclined toward the center O of the lens unit 121. Then, in order to enable the baffle D’ to block the evaporation source W from emitting the evaporated material to the non-lens surface x2 of the lens unit 121, it is necessary to make the minimum inclination angle of the line connecting the innermost point of any evaporation source in the cross section along any radial direction of the Fresnel lens layer to the edge of the corresponding baffle close to the Fresnel lens layer relative to the normal of the plane where the projection screen is located be greater than the maximum inclination angle of the non-lens surface x2 of the lens unit 121 relative to the normal.

FIG52 illustrates a cross section along the symmetry axis II' direction of the projection screen. When setting the inclination angle of the baffle, it is necessary to ensure that the inclination angle of the baffle in the cross section along any radial direction of the Fresnel lens layer satisfies:

Wherein, α _max represents the maximum inclination angle of the non-lens surface of the lens unit in a cross section along any radial direction of the Fresnel lens layer relative to the normal of the plane where the projection screen is located, θ represents the minimum inclination angle of the connecting line between the innermost point of the evaporation source and the edge of the baffle plate close to the Fresnel lens layer in the cross section relative to the normal, S ₁ represents the distance from the innermost point of the evaporation source in the cross section to the normal of the edge of the baffle plate close to the Fresnel lens layer, and h ₁ represents the distance from the plane including the innermost point of the evaporation source to the baffle plate. The distance from the edge of the Fresnel lens layer to the side close to the Fresnel lens layer.

The definitions of the normal line, the innermost point of the evaporation source in the cross section, and the plane including the innermost point of the evaporation source may refer to the above embodiments and will not be repeated here.

As described above, the inclination angle of the lens surface x1 of each lens unit 121 in the Fresnel lens layer 12 relative to the plane where the projection screen is located, and the inclination angle of the non-lens surface x2 of each lens unit 121 relative to the normal of the plane where the projection screen is located may vary. Still taking the projection screen used in the ultra-short-throw projection system as an example, the inclination angle of the lens surface x1 of each lens unit 121 in the Fresnel lens layer 12 relative to the plane where the projection screen is located increases with the increase of the radius of the lens unit 121. For the non-lens surface x2 of each lens unit 121, its inclination angle relative to the normal of the plane where the projection screen is located may change with the lens surface x1, or may remain unchanged.

In some embodiments, as shown in FIG49 , the non-lens surface x2 of each lens unit 121 has the same inclination angle relative to the normal line t of the plane where the projection screen is located. For example, the non-lens surface x1 of each lens unit 121 is perpendicular to the plane where the projection screen is located, that is, α in the above formula (2) = 0. In this case, the inclination angles of the baffles D' located between the evaporation source W and the Fresnel lens layer 12 can be the same, and the baffles D' are parallel to each other.

In some embodiments, as shown in FIG. 52 , the inclination angle of the non-lens surface x2 of each lens unit 121 relative to the normal t of the plane where the projection screen is located increases as the radius of the lens unit 121 increases, that is, the larger the radius of the lens unit 121, the larger the inclination angle of the non-lens surface x2 of the lens unit 121 relative to the normal. In this case, the inclination angle of the baffle D’ needs to be set according to the lens unit 121 to which it corresponds. The width of the lens unit 121 is usually in the micrometer order, while the width of the baffle D’ is usually in the millimeter order. Therefore, one baffle D’ corresponds to multiple lens units 121. According to the above formula (2), the angle of the line connecting the edge of the baffle D’ close to the Fresnel lens layer and the innermost point of the corresponding evaporation source relative to the normal needs to be greater than the maximum angle of the non-lens surface x2 of each lens unit 121 corresponding to the baffle D’ relative to the normal.

In a specific implementation, the distance between the evaporation source and the Fresnel lens layer can be 20 mm to 200 mm, the evaporation source is arranged close to the side of the baffle away from the Fresnel lens layer, the width of the baffle can be 100 mm to 500 mm, and the spacing between adjacent baffles can be 50 mm to 200 mm. For example, the distance between the evaporation source and the Fresnel lens layer can be 100 mm, the width of the baffle can be 200 mm, and the spacing between adjacent baffles can be 100 mm.

Fig. 53 is a schematic diagram of the cross-sectional structure along the B-B' direction in Fig. 40; Fig. 54 is a schematic diagram of the positional relationship of the evaporation source, the baffle and the Fresnel lens layer along the cross section shown in Fig. 53. The B-B' direction and the A-A' direction in Fig. 40 are parallel to each other, that is, they are both parallel to the symmetry axis I-I' of the projection screen along the vertical direction.

In some embodiments, as shown in Figures 53 and 54, a vapor deposition source W can be set on one side of the Fresnel lens layer 12 having multiple lens units 121, so that the vapor deposition source W and the multiple lens units 121 are at a set distance; and a plurality of spaced-apart baffles D’ are set between the vapor deposition source W and the multiple lens units 121, so that the baffles D’ block the vapor deposition material emitted by the vapor deposition source W from forming on the non-lens surface x2 of the lens unit 121.

The difference from the embodiment shown in FIG. 54 is that the cross section shown in FIG. 54 is a cross section along the BB' direction in FIG. 40. When all cross sections of the Fresnel lens layer are cut along the BB' direction parallel to FIG. 40, the size of the inclination angle α' of the non-lens surface x2 of the lens unit 121 relative to the normal t of the plane where the projection screen is located will vary. If the maximum inclination angle α _max ' of the non-lens surface x2 of the lens unit 121 relative to the normal of the plane where the projection screen is located is found in a certain cross section, then the positional relationship between the baffle D' and its corresponding evaporation source W can satisfy:

As shown in FIG54, α _max ' represents the maximum inclination angle of the non-lens surface x2 of the lens unit 121 obtained in all cross sections of the Fresnel lens layer 12 along the direction parallel to BB' relative to the normal of the plane where the projection screen is located, and θ' represents the maximum inclination angle of the non-lens surface x2 of the lens unit 121 obtained in all cross sections of the Fresnel lens layer 12 along the direction parallel to BB'. The minimum inclination angle of the connecting line between the innermost point P of the evaporation source and the edge of the corresponding baffle D' close to the Fresnel lens layer relative to the normal t, S ₁ ' represents the distance from the innermost point P of the evaporation source to the normal t passing through the edge of the baffle D' close to the Fresnel lens layer in the cross section, and h ₁ ' represents the distance from the plane including the innermost point P of the evaporation source to the edge of the baffle D' close to the Fresnel lens layer.

The normal line is the normal line of the plane where the projection screen is located. The innermost point of the evaporation source refers to the point on the side of the corresponding baffle that the evaporation source is farthest from in the above cross section. For example, in FIG54 , the left side of the evaporation source W is closer to the baffle D', and the right side of the evaporation source is farther from the baffle. Therefore, the innermost point of the evaporation source in FIG54 refers to the rightmost point of the evaporation source. The plane including the innermost point P of the evaporation source refers to the plane passing through point P and parallel to the plane where the projection screen is located.

When the positional relationship between the baffle D' and the corresponding evaporation source W satisfies the above formula (3), the structures of the baffle D' and the evaporation source W can be simplified. Specifically, FIG. 55 is a third schematic diagram of the planar structure of the evaporation source, the baffle, and the Fresnel lens layer provided in an embodiment of the present application; FIG. 56 is a fourth schematic diagram of the planar structure of the evaporation source, the baffle, and the Fresnel lens layer provided in an embodiment of the present application.

At this time, as shown in Figure 55, the evaporation source W can be set to a strip extending along the first direction x, and the baffle D’ can be set to a strip extending along the first direction x, and the baffle D’ is no longer a complex structure such as a conical surface, but is set to a plane.

The first direction x is parallel to the plane where the projection screen is located and perpendicular to the symmetry axis I-I' of the projection screen along the vertical direction.

This can simplify the structures of the vapor deposition source and the baffle while preventing the vapor deposition material from being formed on the non-lens surface of the lens unit.

Furthermore, as shown in Fig. 56, if the Fresnel lens layer is moved along the first direction x during evaporation, a film can be formed on the lens surface of the lens unit, thereby improving the productivity of the reflective layer. If combined with a roll-to-roll process, the productivity of the projection screen can be further improved.

In a specific implementation, the distance between the evaporation source and the Fresnel lens layer can be 20 mm to 200 mm, the evaporation source is arranged close to the side of the baffle away from the Fresnel lens layer, the width of the baffle can be 100 mm to 500 mm, and the spacing between adjacent baffles can be 50 mm to 500 mm. For example, the distance between the evaporation source and the Fresnel lens layer can be 100 mm, the width of the baffle can be 200 mm, and the spacing between adjacent baffles can be 100 mm.

According to the same concept, when the functional layer in the projection screen no longer uses Fresnel lenses, but is composed of multiple lens structure layers extending along the above-mentioned first direction and arranged along the symmetry axis I-I’ direction along the vertical direction of the projection screen, the structure of the evaporation source and baffle in the above-mentioned embodiment can also be applied.

Specifically, FIG. 57 is a schematic diagram of the planar structure of the evaporation source, baffle and lens structure layer provided in an embodiment of the present application. As shown in FIG. 57 , the projection screen has a lens structure layer 12 ', and the lens structure layer 12 ' includes a plurality of lens units 121 ', and these lens units 121 ' are all strips extending along the first direction x, and are arranged along the direction of the symmetry axis I-I ' of the projection screen along each lens unit 121 '. Among them, the first direction x is parallel to the plane where the projection screen is located, and the first direction x is perpendicular to the symmetry axis I-I ' of the projection screen along the vertical direction. Similarly, the lens unit 121 ' includes a lens surface and a non-lens surface connected to each other, wherein the lens surface is tilted relative to the plane where the projection screen is located, and the non-lens surface is used to connect the lens surface so that the inclination angle of the lens surface relative to the plane where the projection screen is located satisfies that the projection light incident on the reflective layer on the lens surface can be reflected in the direction where the audience is located.

For the lens structure layer 12' that meets the above-mentioned lens unit 121', the evaporation source W and the baffle D' can both be in the shape of strips extending along the first direction x, and the baffle D' is a plane. The structures of the lens structure layer 12', the evaporation source W and the baffle D' are all simplified.

When all cross sections of the lens structure layer 12' are cut along the direction parallel to I-I' in FIG57, the cross-sectional structure obtained is the same as the cross-sectional structure obtained along the direction I-I' in FIG57. Therefore, the positional relationship that the baffle D' and its corresponding evaporation source W should satisfy is the same as the above formula (2), thereby preventing the evaporation material emitted by the evaporation source W from being formed on the non-lens surface of the lens unit 121'.

When the projection screen is used in an ultra-short-throw projection system, the inclination angle of the lens surface of each lens unit 121' in the lens structure layer 12' relative to the plane where the projection screen is located increases as the distance between the lens unit 121' and the bottom edge of the projection screen increases. As shown in FIG57, the bottom edge of the projection screen is the lower side in FIG57. The inclination angles of the normals of the projection screen are the same. For example, when the non-lens surfaces of the lens units 121' are perpendicular to the plane where the projection screen is located, the inclination angles of the baffles D' located between the evaporation source W and the functional layer 12' can be the same, and the baffles D' are parallel to each other. If the inclination angles of the non-lens surfaces of the lens units 121' relative to the normals of the plane where the projection screen is located increase with the increase of the distance between the lens unit 121' and the bottom edge of the projection screen, then the inclination angles of the baffles D' need to be set for the corresponding lens units 121', and the baffles D' are no longer parallel to each other.

In some embodiments, the reflective layer can be a single-layer structure or a multi-layer composite structure. When the reflective layer is a single-layer structure, any of the above methods can be used to evaporate the reflective metal material on the lens surface of the lens unit. When the reflective layer is a multi-layer composite structure, it can achieve selective reflection of light in a specific wavelength band, thereby further improving the contrast of the projected image.

Finally, after the reflective layer is made, the surface functional layer can also be made. The surface functional layer is located on the outermost side of the projection screen, that is, the side closest to the audience. The surface functional layer plays a role in protecting the projection screen. In addition, the surface functional layer can also be processed in a variety of ways according to different needs to achieve the effects of expanding the viewing angle, resisting ambient light reflection, and resisting ceiling reflection.

Claims (30)

A projection screen, comprising: Surface functional layer; A Fresnel lens layer is located on one side of the surface functional layer; the Fresnel lens layer includes a plurality of lens units, the plurality of lens units are arranged in concentric circles that expand in sequence along the radial direction; the lens unit includes a lens surface that is tilted relative to the plane where the surface functional layer is located; and A reflective layer, at least covering the inclined surface of the lens unit; The inclination angle of the lens surface of each lens unit is sufficient to reflect the light emitted by the projection device to the reflective layer on the lens surface toward the viewer; The lens units are axially symmetrically distributed, the symmetry axis of each lens unit is perpendicular to the horizontal direction, and the center of the lens unit is located on the straight line where the symmetry axis is located; the inclination angle of the lens surface of at least one lens unit in the multiple groups of lens units at the first position is greater than the inclination angle at the second position, and the distance from the first position to the symmetry axis is greater than the distance from the second position to the symmetry axis. The projection screen as claimed in claim 1, wherein the center of each of the lens units included in the projection screen is not located in the projection screen, and the inclination angles of the lens surfaces of all the lens units included in the projection screen increase with the increase of the vertical distance from the lens surface to the symmetry axis. The projection screen according to claim 2, wherein the variation of the inclination angle of the lens surface of the same lens unit satisfies a sine function. The projection screen according to claim 3, wherein the inclination angle of the lens surface of each of the lens units increases along the radial direction as the radius of the lens unit increases. The projection screen according to claim 4, wherein the amplitude of the sine function satisfied by the inclination angle of the lens surface of each of the lens units increases as the radius of the lens unit increases. The projection screen according to claim 5, wherein the variation of the inclination angle of the lens surface of the same lens unit is greater than 0 and less than or equal to 2.25°. The projection screen of claim 6, wherein the amount of change in the inclination angle of the lens surface of the lens unit increases as the size of the projection screen increases. The projection screen according to claim 1, wherein the inclination angles of the lens surfaces of the same lens unit at positions symmetrical to each other about the symmetry axis are equal. The projection screen according to claim 1, wherein the reflection layer is a wavelength selective reflection layer, and the reflectivity of the wavelength selective reflection layer to the projection light emitted by the projection device is greater than the reflectivity of light in other wavelength bands; The wavelength selective reflection layer has an equal thickness along a direction perpendicular to the lens surface. The projection screen according to claim 9, wherein the inclination angle of the lens surface of each of the lens units increases along the radial direction as the radius of the lens unit increases; The thickness of the wavelength selective reflection layer along a plane perpendicular to the projection screen increases as the radius of the lens unit increases. The projection screen as claimed in claim 1, wherein any light-transmitting film layer in the projection screen contains a low-valent oxide; the low-valent oxide is used to reduce the transmittance in the visible light band. The projection screen of claim 11, wherein the suboxide is a metal suboxide; The absorption capacity of the low-valent oxide to the visible light band decreases with the increase of oxygen content. The projection screen according to claim 11, wherein the reflection layer is a wavelength selective reflection layer, and the reflectivity of the wavelength selective reflection layer to the projection light emitted by the projection device is greater than the reflectivity of light in other wavelength bands; The wavelength selective reflection layer comprises: Reflective layer; and At least one film layer group is located on a side of the reflective layer facing the surface functional layer; the film layer groups are stacked; Wherein, the film layer group comprises: a semi-transmissive layer, located on a side close to the surface functional layer; and The light-transmitting medium layer is located between the semi-transmitting layer and the reflective layer; the product of the refractive index and the thickness of the light-transmitting medium layer satisfies the condition for causing the outgoing light of the projection device to resonate. The projection screen of claim 13, wherein the light-transmitting medium layer comprises the subvalent oxide. The projection screen as claimed in claim 13, wherein the light-transmitting medium layer comprises the low-valent oxide and the complete oxide. The projection screen as claimed in claim 15, wherein the light-transmitting medium layer comprises a first medium layer and a second medium layer stacked in layers; wherein the first medium layer is made of a low-valent oxide and the second medium layer is made of a complete oxide; or, the first medium layer is made of a complete oxide and the second medium layer is made of a low-valent oxide. The projection screen according to claim 14 or 15, wherein the low-valent oxide is one of Nb ₂ O _5-x , TiO _2-y or Ta ₂ O _5-z ; Among them, 0＜x＜5, 0＜y＜2, 0＜z＜5. The projection screen according to claim 13, wherein the semi-transmissive layer is a laminated structure formed by at least one metal selected from aluminum, niobium, silver and titanium; and the thickness of the semi-transmissive layer is 2 nm to 20 nm; The material of the reflective layer is aluminum, aluminum alloy, silver or silver alloy; the thickness of the reflective layer is greater than 50nm; The product of the thickness and the refractive index of the light-transmitting medium layer is 1200-1800. A projection system, comprising: A projection device for emitting projection light; and A projection screen, located at the light-emitting side of the projection device, wherein the projection screen is the projection screen according to any one of claims 1 to 18; Wherein, the projection device is an ultra-short-throw laser projection device; the projection device comprises: A three-color laser light source device, used for emitting three-primary-color lasers; a light modulation component, located at the light output side of the three-color laser light source device, and used to modulate the output laser light of the three-color laser light source device; and The projection lens is located at the light-emitting side of the light modulation component. A method for manufacturing a projection screen, comprising: Fresnel lens layer manufacturing process: manufacturing a Fresnel lens layer; a surface of one side of the Fresnel lens layer has a plurality of lens units, each of the lens units is in the shape of concentric circles that are sequentially expanded and arranged along the radial direction; the lens unit includes a lens surface and a non-lens surface that are connected to each other; Wavelength selective reflection layer manufacturing process: forming a wavelength selective reflection layer on the surface of the lens unit; the thickness of the wavelength selective reflection layer along the plane perpendicular to the projection screen increases as the radius of each lens unit increases; and A surface functional layer manufacturing step: forming a surface functional layer on one surface of the Fresnel lens layer having the wavelength selective reflection layer. The manufacturing method according to claim 20, wherein the wavelength selective reflection layer comprises a semi-transparent layer, a reflective layer and a transparent medium layer; the semi-transparent layer, the reflective layer and the transparent medium layer are all manufactured by a sputtering process; The light-transmitting medium layer is manufactured by a sputtering process, comprising: A correction plate is arranged above the sputtering source; A Fresnel lens layer is arranged above the correction plate, so that the lens unit of the Fresnel lens layer faces the sputtering source; Rolling the Fresnel lens layer during the sputtering process so that the Fresnel lens layer moves along a first direction above the sputtering source; Wherein, the correction plate includes a plurality of sub-correction plate pairs, the sub-correction plate pairs include two sub-correction plates, and a gap of a set distance is provided between the two sub-correction plates; each of the sub-correction plate pairs is arranged along a second direction; the first direction is perpendicular to the second direction, the second direction is perpendicular to a first side edge of the projection screen, and the first side edge is a side edge close to the center of the circle of the lens unit; the gap of each of the sub-correction plate pairs along the second direction increases as the radius of each lens unit increases. A method for manufacturing a projection screen, comprising: A Fresnel lens layer is manufactured; a surface of one side of the Fresnel lens layer has a plurality of arc-shaped lens units, and the arc-shaped lens units are concentrically arranged; each of the lens units comprises a lens surface and a non-lens surface connected to each other, the lens surface is inclined relative to the plane where the projection screen is located, and the non-lens surface is used to connect the lens surface; A vapor deposition source is arranged at a set position of the Fresnel lens layer to form a reflective layer on the lens surface of the plurality of lens units; the vapor deposition source is located on one side of the Fresnel lens layer having the plurality of lens units, and a set distance is provided between the vapor deposition source and the plurality of lens units; A surface functional layer is formed on a side of the Fresnel lens layer facing away from the reflective layer. The manufacturing method according to claim 22, wherein the evaporation source is provided at the set position of the Fresnel lens layer, comprising: The arc-shaped vapor deposition source is disposed at a set position of the Fresnel lens layer. The manufacturing method according to claim 23, wherein the center of the arc-shaped evaporation source coincides with the center of the lens unit in the orthographic projection on the plane where the projection screen is located; the radius of the arc-shaped evaporation source is greater than the radius of any lens unit in the Fresnel lens layer; The radius of the arc-shaped evaporation source relative to all lens units in the Fresnel lens layer satisfies:
Wherein, α _i represents the inclination angle of the non-lens surface of the i-th lens unit in a cross section along any radial direction of the Fresnel lens layer relative to the normal of the plane where the projection screen is located, θ _i represents the inclination angle of the line connecting the innermost point of the evaporation source and the vertex of the i-th lens unit in the cross section relative to the normal, S _i represents the distance from the innermost point of the evaporation source in the cross section to the normal passing through the vertex of the i-th lens unit, and h represents the distance from the plane including the innermost point of the evaporation source to the vertex of the i-th lens unit; The innermost point of the evaporation source is the point in the cross section that is closest to the center of a circle, and the center of a circle is the center of the evaporation source arranged in an arc shape; the vertex of the lens unit is the intersection of the lens surface and the non-lens surface of the lens unit in the cross section that are close to the evaporation source; the plane including the innermost point of the evaporation source is parallel to the plane where the projection screen is located; i is any positive integer less than or equal to the number of lens units in the Fresnel lens layer. The manufacturing method according to claim 22, wherein the evaporation source is provided at the set position of the Fresnel lens layer, comprising: Disposing an arc-shaped evaporation source at a set position of the Fresnel lens layer; A plurality of baffles arranged at intervals are provided between the evaporation source and the plurality of lens units, and the baffles are used to block the evaporation material emitted from the evaporation source from being formed on the non-lens surface of the lens unit. The manufacturing method as described in claim 25, wherein the shape of the baffle is a partial surface of a conical surface; the vertex of the conical surface where the baffle is located coincides with the center of the lens unit in the orthographic projection on the plane where the projection screen is located. The manufacturing method according to claim 26, wherein the baffle satisfies:
Wherein, α _max represents the maximum inclination angle of the non-lens surface of the lens unit relative to the normal of the plane where the projection screen is located in a cross section along any radial direction of the Fresnel lens layer, θ represents the minimum inclination angle of the connecting line between the innermost point of the evaporation source and the edge of the baffle plate close to the Fresnel lens layer in the cross section relative to the normal, S ₁ represents the minimum distance from the innermost point of the evaporation source in the cross section to the normal passing through the edge of the baffle plate close to the Fresnel lens layer, and h ₁ represents the distance from the plane including the innermost point of the evaporation source to the edge of the baffle plate close to the Fresnel lens layer; The innermost point of the evaporation source is the point in the cross section that is closest to the center of a circle, and the center of a circle is the center of the evaporation source arranged in an arc shape; the plane including the innermost point of the evaporation source is parallel to the plane where the projection screen is located. The manufacturing method according to claim 22, wherein the evaporation source is provided at the set position of the Fresnel lens layer, comprising: Disposing a strip-shaped evaporation source at a set position of the Fresnel lens layer; A plurality of baffles arranged at intervals are provided between the evaporation source and the plurality of lens units, and the baffles are used to block the evaporation material emitted from the evaporation source from being formed on the non-lens surface of the lens unit. The manufacturing method according to claim 28, wherein the strip-shaped evaporation source extends along a first direction, the first direction is parallel to the plane where the projection screen is located, and the first direction is perpendicular to the symmetry axis of the projection screen along the vertical direction; The baffle is in the shape of a strip extending along the first direction, the baffle is a plane, and the baffle is arranged obliquely relative to the plane where the projection screen is located. The manufacturing method according to claim 29, wherein the baffle satisfies:
wherein α _max ' represents the maximum inclination angle of the non-lens surface of the lens unit relative to the normal of the plane where the projection screen is located in any cross section of the projection screen along the perpendicular direction, θ' represents the minimum inclination angle of the connecting line between the innermost point of the evaporation source and the edge of the baffle plate close to the Fresnel lens layer in the cross section relative to the normal, S ₁ ' represents the minimum distance from the innermost point of the evaporation source in the cross section to the normal passing through the edge of the baffle plate close to the Fresnel lens layer, and h ₁ ' represents the distance from the plane including the innermost point of the evaporation source to the edge of the baffle plate close to the Fresnel lens layer; The innermost point of the evaporation source is the point in the cross section that is farthest from the corresponding side of the baffle; the plane including the innermost point of the evaporation source is parallel to the plane where the projection screen is located.