JP2015075535A - Transmission type screen and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curved transmission type screen configured to suppress generation of moire.SOLUTION: A transmission type screen displays an image by transmitting image light projected on one side of a surface to the other side of the surface. The transmission type screen includes: an optical functional layer comprising a plurality of light-transmitting sections for transmitting light, which extend in one direction and are juxtaposed in a direction different from the extending direction thereof, and light absorbing sections for absorbing light, each being formed between adjacent light transmitting sections; and a Fresnel lens layer having unit lenses which extend in one direction and are juxtaposed in a direction different from the extending direction. In frontal view, the extending direction of the light transmitting sections and light absorbing sections intersects with the extending direction of the unit lenses.

Description

  The present invention relates to a transmissive screen that displays video by transmitting image light projected from one surface side to the other surface side, and a display device including the transmissive screen.

  As one of display devices that display video and images, there is a rear projection display device. This rear projection display device is also referred to as a rear projection display device, and is a display device that projects image light from an image light source on the back side of a transmissive screen and emits an image on the front side (observer side) of the screen. . The transmissive screen provided in the rear projection display device has a Fresnel lens layer and various optical functions so that an observer can observe an appropriate and high-quality image when emitting image light from the image light source to the front side. Layers are provided.

  Patent Document 1 discloses a technique in which such a transmissive screen has an excellent appearance when it has a three-dimensional curved surface. Thereby, for example, a transmissive screen can be formed with a curved surface along the curve of the console portion of the automobile, and a sense of unity between the display device and the interior of the automobile can be produced.

JP 2012-159646 A

  A transmissive screen is usually configured by laminating layers having various functions. For example, as disclosed in Patent Document 1, the transmissive screen includes a linear Fresnel lens layer that includes a plurality of unit lenses that extend in one direction and are arranged in parallel in the other direction. Patent Document 1 also discloses that an optical functional layer that includes a plurality of light transmission portions and light absorption portions that extend in one direction and are arranged in parallel in the other direction is also disclosed.

  However, in a curved transmission screen, when a layer including a plurality of unit optical elements arranged in parallel in a predetermined direction is used in addition to the linear Fresnel lens, there is a problem that moire may occur.

  Therefore, an object of the present invention is to provide a curved transmission screen that can suppress the occurrence of moire. In addition, a display device including the transmission screen is provided.

  The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.

  According to the first aspect of the present invention, the image light projected from one surface side is transmitted to the other surface side to display an image, and the transmission type has a curved portion so as to be convex on the one surface side. A screen (10) formed between a plurality of light transmitting portions (18) that transmit light and that are arranged in parallel in a direction different from the extending direction and adjacent light transmitting portions. An optical functional layer (17) including a light absorbing portion (19) for absorbing light, and a Fresnel including a unit lens (24) extending in one direction and arranged in a direction different from the extending direction. The transmissive screen includes a lens layer (21), and in a front view, the direction in which the light transmission part and the light absorption part extend intersects with the direction in which the unit lens extends.

  According to a second aspect of the present invention, in the front view of the transmissive screen according to the first aspect, there are a direction in which the light transmission part (18) and the light absorption part (19) extend and a direction in which the unit lens (24) extends. The intersecting angle is 3 ° or more and 10 ° or less.

  A display according to a third aspect of the present invention comprises: a video light source that emits video light; and a transmission screen according to claim 1 or 2 that transmits the video light from the video light source and emits it to the viewer side. Device.

  According to the present invention, it is possible to suppress the occurrence of moire in a curved transmission screen.

2 is a diagram conceptually showing an internal structure of a rear projection display device 1. FIG. 1 is a perspective view of a transmissive screen 10. FIG. 3 is a vertical sectional view for explaining a layer structure of a transmission screen 10. FIG. 3 is a front view of the transmission screen 10 focusing on the optical function layer 17 and the Fresnel lens layer 21. FIG. It is a figure explaining the metal mold | die used for shaping | molding of a Fresnel lens. It is sectional drawing of the perpendicular direction explaining the laminated constitution of the transmissive screen 10 '. It is sectional drawing explaining the optical function layer produced in the Example.

  The above-described operation and gain of the present invention will be clarified from embodiments for carrying out the invention described below. Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to these embodiments. In the drawings shown below, the size and ratio of members may be changed or exaggerated for easy understanding. Moreover, the code | symbol which becomes repeated may be abbreviate | omitted for legibility.

  FIG. 1 is a diagram for explaining one embodiment, and is a diagram conceptually showing a part of the internal structure of a rear projection display device 1 (hereinafter sometimes referred to as “display device 1”). .

The display device 1 includes a transmissive screen 10, and the video light I emitted from the video light source 3 is provided to the viewer through the transmissive screen 10. For example, the display device 1 is built in a dashboard portion of an automobile, and the viewer side surface of the transmissive screen 10 is disposed so as to be exposed in the vehicle, and provides an image to the viewer.
As can be seen from FIG. 1, the display device 1 includes a housing 2, an image light source 3, and a transmissive screen 10. In addition, although illustration is omitted, the display device 1 includes various components for functioning as a display device.

  The housing 2 is a member that forms an outer shell of the display device 1 and that accommodates most of the members constituting the display device 1 therein. The housing 2 has an opening capable of supporting the transmissive screen 10, and the transmissive screen 10 is fitted and attached to the opening.

  The image light source 3 is disposed in the housing 2 and irradiates the image light on almost the entire light incident surface of the transmissive screen 10 as divergent light in which the irradiation area gradually expands. Here, the light incident surface of the transmissive screen 10 means a surface of the transmissive screen 10 on the side where the image light source 3 is disposed. On the other hand, the light exit surface of the transmissive screen 10 means a surface directed toward the observer side. As such an image light source 3, a conventionally known light source, for example, a single tube type light source using DMD can be used.

  Next, the transmission screen 10 will be described. 2 is a perspective view of the transmission screen 10, and FIG. 3 is a cross-sectional view in the thickness direction of the transmission screen 10 in the vertical direction along the line III-III in FIG. FIG. As can be seen from FIGS. 1 to 3, the transmission screen 10 has a plate shape as a whole, but is formed in a convex curved surface whose center protrudes toward the viewer. As a result, it is possible to provide a transmission screen having an excellent appearance and a display device including the transmission screen.

  FIGS. 1 to 3 illustrate a transmissive screen 10 having a curved surface whose central portion is convex toward the viewer. However, the position and number of protrusions are not particularly limited. Further, the convex direction is not limited, and may be convex toward the image light source side (back side) (that is, concave when viewed from the observer side). Furthermore, it may be configured such that the direction of the unevenness is changed depending on the site by one transmission type screen.

  The transmissive screen 10 is a screen that transmits image light incident from the light incident surface side (image light source side) to the light exit surface side (observer side). As can be seen from FIG. 3, the transmission screen 10 includes a laminated body 11 and a Fresnel lens layer 21, and the laminated body 11 and the Fresnel lens layer 21 have a curved portion so as to be convex on one surface side. ing. Further, as can be seen from FIG. 3, the laminate 11 has a structure in which a plurality of layers are laminated in the thickness direction. From the light exit surface side (observer side), the support body 12, the adhesive layer 13, and the light A diffusion layer 15, an adhesive layer 16, an optical function layer 17, and a base material layer 20 are provided. Hereinafter, these elements constituting the transmission screen 10 will be described in detail.

  The support 12 is a plate-like member having translucency. The support 12 is a sheet-like member that imparts a predetermined stiffness to the laminate 11, and is formed of a material that has translucency and can impart the stiffness. Such a material is not particularly limited, and glass, resins such as methyl methacrylate / butadiene / styrene copolymer (MBS), acrylic, polycarbonate, and the like can be used.

  The adhesive layer 13 is a layer containing an adhesive for adhering the support 12 and the light diffusion layer 15. The adhesive used for the adhesive layer 13 is not particularly limited as long as it can transmit light and can adhere the support 12 and the light diffusion layer 15 to each other. For the adhesive layer 13, for example, an ultraviolet curable resin can be used.

  The light diffusion layer 15 is a layer having a function of diffusing transmitted light. Specifically, the light diffusion layer 15 has a base portion made of a transparent resin and a diffusion component dispersed in the base portion. The light diffusion layer 15 can diffuse light due to the difference in refractive index between the base portion and the diffusion component or due to the reflectivity of the diffusion component itself. With this function of the light diffusion layer 15, the image light is diffused and a predetermined viewing angle can be obtained.

As the transparent resin forming the base portion of the light diffusion layer 15, for example, methyl methacrylate / butadiene / styrene copolymer (MBS), acrylic resin, polycarbonate resin, or the like can be used.
On the other hand, as the diffusing component, organic fillers such as plastic beads are preferable, and those having high transparency are particularly preferable. Examples of the plastic beads include melamine beads, acrylic beads, acrylic-styrene beads, polycarbonate beads, polyethylene beads, polystyrene beads, and vinyl chloride beads. Among these, acrylic beads are preferable. In addition, the diffusion component can be composed of bubbles.

  The thickness of the light diffusion layer 15 is preferably from 0.1 mm to 2.0 mm, and more preferably from 0.2 mm to 1.5 mm. When the thickness of the light diffusion layer 15 is less than 0.1 mm, there is a possibility that the light diffusion effect cannot be obtained sufficiently. On the other hand, if the thickness of the light diffusion layer 15 exceeds 2.0 mm, the image may be blurred.

  The adhesive layer 16 is a layer containing an adhesive for adhering the optical function layer 17 and the light diffusion layer 15. The material of the adhesive used for the adhesive layer 16 is not particularly limited as long as it can transmit light and the optical functional layer 17 can be adhered to the other. For the adhesive layer 16, for example, an ultraviolet curable resin can be used.

  The optical function layer 17 has a function of transmitting image light and absorbing at least part of unnecessary light. The optical functional layer 17 is laminated on the viewer side of the base material layer 20, and adjacent to the plurality of light transmission parts 18 arranged in parallel so as to transmit light along one surface of the base material layer 20. A light absorbing portion 19 arranged in parallel between the two light transmitting portions 18. In this embodiment, the light transmitting portion 18 and the light absorbing portion 19 have the cross section shown in FIG. 3 and extend in one direction (in this embodiment, the horizontal direction), and are different from the extending direction (in this embodiment). A plurality of light transmission portions 18 and light absorption portions 19 are alternately arranged in parallel in the vertical direction).

  The light transmission part 18 is a part having a function of transmitting image light, and is an element having a substantially trapezoidal cross section in the cross section shown in FIG. The upper base in the substantially trapezoidal cross section is arranged on the viewer side, and the lower base longer than the upper base is arranged on the Fresnel lens layer 21 side. In this embodiment, the lower bottom side (Fresnel lens layer 21 side) of the adjacent light transmission portions 18 is connected.

  The light transmission part 18 is formed of a material having light transparency. Such a material is not particularly limited. For example, a transparent resin mainly composed of one or more of acrylic, styrene, polycarbonate, polyethylene terephthalate, acrylonitrile, etc., and an epoxy acrylate or urethane acrylate reactive resin. (Ionizing radiation curable resin or the like) can be used. Here, the refractive index of the light transmitting portion 18 is not particularly limited, but is preferably 1.49 to 1.56 from the viewpoint of availability of a material to be applied.

The light absorbing portion 19 is a portion having a function of absorbing light formed between the adjacent light transmitting portions 18 and has a substantially trapezoidal shape in this embodiment. Therefore, the light absorbing portion 19 contains a material that absorbs light, and the upper base in the substantially trapezoidal cross section is directed to the Fresnel lens layer 21 side, and the lower base longer than the upper base is directed to the observer side, which is the opposite side. It has been.
Here, it is preferable that the hypotenuse (leg part) in the substantially trapezoidal cross section of the light absorption part 19 forms an angle of 0 degrees or more and 10 degrees or less with respect to the thickness direction of the optical function layer 17. In the present embodiment, the light absorbing portion 19 has an example of a substantially trapezoidal cross section, but is not limited thereto, and may be a square, a rectangle, or a parallelogram. Further, the inclination of the hypotenuse does not necessarily have to be constant, and may be a polygonal line that changes depending on the position of the optical function layer 17 in the thickness direction, or may be a curved line. Further, the length of the upper base of the light absorbing portion 19 can be reduced to make the cross section substantially triangular.

Such a light absorption part 19 can be formed, for example, by containing a light-absorbing material in a transparent resin.
As the transparent resin, for example, an ionizing radiation curable resin can be used, and is not particularly limited. However, for example, urethane acrylate type, epoxy acrylate type, etc. having characteristics of being cured by ionizing radiation such as electron beam and ultraviolet ray. An acrylate resin can be used.
On the other hand, the light-absorbing material only needs to have a function of absorbing unnecessary light such as stray light and external light that is visible light, such as carbon black, graphite, metal salts such as black iron oxide, pigments, Mention may be made of dyes.

Moreover, when it has a function which detects the contact to the transmissive screen 10 by infrared rays, it is preferable that infrared light permeate | transmits the inside of the transmissive screen 10 efficiently. Therefore, at this time, it is preferable that the light-absorbing material absorbs visible light while transmitting infrared light.
As a light absorber capable of transmitting infrared light, a light absorber made of ink mixed with a pigment or dye can be used. Examples of the pigment include perylene black pigment, aniline black pigment, format black (mixed pigment of yellow, magenta and cyan pigment), phthalocyanine blue, brilliant carmine and the like. Furthermore, when the light absorber is resin particles colored with pigments or dyes, specific examples of the resin particles include plastic beads such as melamine beads, acrylic beads, acrylic-styrene beads, polycarbonate beads, polyethylene beads, polystyrene beads, and the like. Among them, acrylic beads are preferably used among these.

  The base material layer 20 is a layer that becomes a base material for forming the optical functional layer 17. The main component of the material which comprises the base material layer 20 will not be specifically limited if it has translucency. The “main component” means a component that is contained in an amount of 50% by mass or more based on the entire material constituting the layer (the same applies hereinafter). Examples of the main component of the material constituting the base material layer 20 include polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, terephthalic acid-isophthalic acid-ethylene glycol copolymer, terephthalic acid-cyclohexanedimethanol-ethylene. Polyester resins such as glycol copolymers, polyamide resins such as nylon 6, polyolefin resins such as polypropylene and polymethylpentene, acrylic resins such as polymethyl methacrylate, styrenes such as polystyrene and styrene-acrylonitrile copolymers Examples thereof include a resin, a cellulose resin such as triacetyl cellulose, an imide resin, and a polycarbonate resin. Among these, polycarbonate resin is preferable from the viewpoints of availability, cost, adhesion with ionizing radiation curable resin, and the like. In addition to the main component, other resins and various additives may be appropriately added to the resin constituting the base material layer 20. Examples of general additives include phenol-based antioxidants, lactone-based stabilizers, and the like. Moreover, you may add well-known additives, such as a ultraviolet absorber, a filler, a plasticizer, an antistatic agent, in these resins suitably as needed.

  The sheet provided with the optical function layer 17 and the base material layer 20 is manufactured as follows, for example. First, the light transmission part 18 is formed on the base material that becomes the base material layer 20. In order to form the light transmission part 18, a mold roll having a surface shape corresponding to the shape of the light transmission part 18 is prepared. Next, the base material is fed between the mold roll and the nip roll. In accordance with the feeding of the base material, droplets of the composition constituting the light transmission portion 18 are continuously supplied between the mold roll and the base material. When the composition is supplied onto the base material, a bank in which the composition is accumulated is formed between the mold roll and the base material. In this bank, the composition spreads in the width direction of the substrate.

  The composition supplied between the mold roll and the base material as described above is filled between the base material and the mold roll by the pressing force between the mold roll and the nip roll. Thereafter, the light transmissive part 18 can be formed by irradiating the composition with ultraviolet rays or the like with a light irradiation device and curing the composition. After forming the light transmitting portion 18 in this way, the sheet having the light transmitting portion 18 formed on the base material is peeled off from the mold roll and cut into a predetermined size, whereby the base material layer 20 and the An intermediate member in which the light transmission part 18 is formed on the base material layer 20 is obtained.

The intermediate member obtained as described above is excessively supplied with the composition constituting the light absorbing portion 19 before being cured, and moved so as to be pressed and scraped with a blade. As a result, the excess composition is removed and the composition is filled between the adjacent light transmission portions 18. Thereafter, the composition is cured by an appropriate method. Thereby, the light absorption part 19 can be formed between the light transmission parts 18.
Thus, a sheet in which the optical functional layer 17 is laminated on the base material layer 20 can be obtained.

  Next, the Fresnel lens layer 21 will be described. It is preferable that the Fresnel lens layer 21 is disposed on the light incident surface side of the multilayer body 11 and is curved so as to be convex in the same direction as the multilayer body 11. The Fresnel lens layer 21 includes a base portion 22 and a Fresnel lens portion 23 formed on the surface of the base portion 22 on the viewer side.

  The base portion 22 is a portion serving as a base for forming the Fresnel lens portion 23. Therefore, the base portion 22 has translucency and is configured to have such strength that the Fresnel lens portion 23 can be formed and held. Specific examples of the material constituting the base portion 22 include films of polycarbonate, cycloolefin, TAC (Triacetylcellulose), and the like. Among these, polycarbonate is preferable from the viewpoint of availability and cost. The polycarbonate used herein is one having polycarbonate as a main polymer, and may include, for example, a filler such as a deterioration inhibitor, a plasticizer, and a softener, or a composite with a methacrylic resin or the like.

  The thickness of the base portion 22 (the thickness of the portion excluding the Fresnel lens portion 23 of the Fresnel lens layer 21. That is, the thickness of the thinnest portion of the Fresnel lens layer 21) is preferably 1 mm or more and 2 mm or less. By setting the thickness of the base portion 22 to 1 mm or more, it becomes easy to impart sufficient rigidity to the Fresnel lens layer 21. On the other hand, by setting the thickness of the base portion 22 to 2 mm or less, it is possible to prevent problems such as an excessive increase in the thickness of the transmissive screen 10, a decrease in image light transmittance, and a ghost (double image). It becomes easy to do.

  The Fresnel lens unit 23 has a function of deflecting the traveling direction of the image light projected from the image light source 3 onto the transmissive screen 10 as a divergent light beam. Specifically, the Fresnel lens unit 23 converts the image light incident as a divergent light beam into a parallel light beam traveling from the image light incident side toward the image light emitting side, for example, a parallel light beam traveling in the front direction. In this way, by using the Fresnel lens portion 23 to once convert the image light into a parallel light flux, it is possible to effectively reduce the inner surface variation in the brightness of the image observed by the observer, in particular, the image observed by the observer from an oblique direction. Can be relaxed.

  FIG. 4 shows a partial front view (viewed from the observer side) of the transmissive screen 10 in which attention is paid to the optical functional layer 17 and the Fresnel lens layer 21. As can be seen from FIGS. 3 and 4, the Fresnel lens portion 23 of this embodiment is a so-called linear Fresnel lens, and includes a plurality of unit lenses 24 that extend in one direction and are arranged in a direction different from the extending direction. Yes. Further, when the transmission screen 10 is viewed from the front, the direction in which the light transmission unit 18 and the light absorption unit 19 extend intersects with the direction in which the unit lens 24 extends. As the cross-sectional shape of each unit lens 24, a publicly known one can be used according to the purpose.

  As described above, the occurrence of moire can be suppressed by intersecting the direction in which the light transmitting portion 18 and the light absorbing portion 19 extend with the direction in which the unit lens 24 extends. When the transmissive screen is curved, the pitch of the unit lenses constituting the Fresnel lens is widened as described below, which may cause moire.

  When the central portion C (see FIG. 3) of the Fresnel lens is in the plane of the screen, a mold for molding the Fresnel lens is produced using two cutting tools as shown in FIG. The central portion of the Fresnel lens means a portion where the inclination direction of the inclined surface of the unit lens is switched in the Fresnel lens. For example, in the example shown in FIG. 3, the unit lens above the center portion C is inclined downward from the back side to the viewer side, and the unit lens below the center portion C is from the viewer side above to the back side. Inclined downward.

  FIG. 5A is a perspective view of a roll mold capable of molding a Fresnel lens, and FIG. 5B is a cross-sectional view of a broken line portion shown in FIG. As shown in FIG. 5B, when the Fresnel lens is molded so that the center of the Fresnel lens is in the plane of the screen, the left and right sides of the mold 200 are used by using two cutting tools 201 and 202 having different directions. The groove 203 corresponding to the unit lens constituting the Fresnel lens is cut from both ends. By cutting the groove 203 with the two cutting tools 201 and 202 from the left and right sides of the mold 200 as described above, uncut portions may occur at the center of the groove 203a at the center of the mold 200. In this way, when an uncut portion is generated in the mold 200, a groove corresponding to the uncut portion is formed in the Fresnel lens. Therefore, when the Fresnel lens is bent, the pitch of the unit lens is easily shifted. . In some cases, the deviation of the pitch of the unit lens generated as described above may cause moire. Even in such a case, the occurrence of moire can be suppressed by intersecting the extending direction of the light transmitting part 18 and the light absorbing part 19 and the extending direction of the unit lens 24 as described above. However, when the width of the groove formed in the Fresnel lens exceeds 10 μm, the Fresnel lens is not suitable for the transmission screen.

  From the viewpoint of suppressing the occurrence of moire as described above, in the front view of the transmissive screen 10, the direction in which the light transmitting portion 18 and the light absorbing portion 19 extend and the direction in which the unit lens 24 extends (the ridge line 24a of the unit lens 24 is The angle θ (see FIG. 4) at which the crossing direction extends is preferably 3 ° or more. Further, from the viewpoint of easily exerting a desired optical function in the optical functional layer 17 disposed on the viewer side from the Fresnel lens layer 21, the light transmission unit 18 and the light absorption unit in the front view of the transmission screen 10. The angle θ (see FIG. 4) at which the direction in which 19 extends and the direction in which the unit lens 24 extends (the direction in which the ridge line 24a of the unit lens 24 extends) is preferably 10 ° or less. If the angle θ (see FIG. 4) exceeds 10 °, there is a possibility that the difference in viewing angle between the left and right or up and down directions of the transmission screen 10 becomes too large. Hereinafter, the angle θ is more preferably 7 ° or more and 8 ° or less.

As resin which comprises the Fresnel lens part 23, transparent resins, such as an acrylic resin, a styrene resin, a polyester resin, a polycarbonate resin, an acryl-styrene copolymer resin, can be mentioned.
When the size of the transmission screen 10 is large, epoxy acrylate or urethane acrylate reactive resin (ionizing radiation curable resin or the like) can be used from the viewpoint of moldability.

  The transmission screen 10 described above can be manufactured as follows, for example.

  First, the optical functional layer 17 can be produced as described above. The light diffusion layer 15 can be produced by extrusion. The optical functional layer 17 and the light diffusing layer 15 thus produced are bonded through the adhesive layer 16. Next, the adhesive layer 13 is formed on the surface of the light diffusing layer 15 opposite to the side on which the optical functional layer 17 is provided, and the adhesive layer 13, the light diffusing layer 15, the adhesive layer 16, the optical functional layer 17 and the base material are formed. A laminated sheet provided with the layer 20 is obtained. Then, the adhesive layer 13 of the laminated sheet is bonded to the curved support body 12 prepared in advance so that the both layers are bonded together by a high-temperature vacuum laminating apparatus, and the adhesive layer 13 is cured by an appropriate method. The curved laminated body 11 provided with the body 12, the adhesive layer 13, the light diffusion layer 15, the adhesive layer 16, the optical function layer 17, and the base material layer 20 is obtained.

  In addition, the curved laminated body 11 can also be produced as follows. A laminated sheet including the light diffusing layer 15, the adhesive layer 16, the optical function layer 17, and the base material layer 20 is bonded to the uncurved support body 12 through the adhesive layer 13, and the laminated body 11 that is not curved is attached. obtain. Next, the laminate 11 before being bent is softened by heating it to a temperature higher than the glass transition temperature of the resin constituting the laminate 11. This temperature is determined by the resin used, but is preferably 60 ° C to 250 ° C, more preferably 70 ° C to 200 ° C. Then, the softened laminate 11 is pressed against a mold (not shown) having a predetermined curved surface shape by using, for example, a pressing member or gas pressure, or heated to set the softened laminate 11 in a mold. Then, it is molded into a curved shape using vacuum pressure or compressed air. The curved laminated body 11 can be obtained by cooling in this state.

  On the other hand, the Fresnel lens layer 21 can be produced by a known method. That is, a material before curing to be the Fresnel lens portion 23 is filled between the sheet-like member that becomes the base portion 22 and a mold having an uneven shape capable of forming the Fresnel lens portion 23. And the material before the said hardening is hardened using a suitable hardening means. Thereby, the Fresnel lens layer in a state before being bent can be obtained. Next, the Fresnel lens layer before being bent is heated and softened, and, for example, a curved surface is formed so that the Fresnel lens portion 23 side is convex. Specifically, it is softened by heating to a temperature higher than the glass transition temperature of the resin constituting the Fresnel lens layer before bending. This temperature is determined by the resin used, but is preferably 60 ° C to 250 ° C, more preferably 70 ° C to 200 ° C. Then, this softened Fresnel lens layer is pressed against a mold (not shown) having a predetermined curved surface shape using, for example, a pressing member or gas pressure. The curved Fresnel lens layer 21 can be obtained by cooling the Fresnel lens layer in this state.

  The transmissive screen 10 can be obtained by performing positioning by fixing the outer edges of the curved laminated body 11 and the curved Fresnel lens layer 21 formed as described above with a frame or the like.

  According to the display device 1 including the transmission screen 10 described above, it is possible to provide image light to an observer as follows, for example. This will be described with an example of the optical path. However, the optical path examples shown here are conceptual and do not strictly represent reflection angles, refraction angles, or the like.

As shown in FIG. 1, the image light L <b> 1 emitted from the image light source 3 reaches the light incident surface side of the transmissive screen 10.
The image light that has reached the light incident surface side of the transmission screen 10 in this way is, as shown by image light L31 and L32 in FIG. It is deflected so as to be parallel to the front direction.

  The image light deflected in the Fresnel lens layer 21 passes through the base material layer 20, the light transmission part 18, the adhesive layer 16, the light diffusion layer 15, the adhesive layer 13 and the support 12, and is emitted to the viewer side. .

  On the other hand, at least a part of external light (light from sunlight, room light, etc.) incident on the transmissive screen 10 from obliquely above from the viewer side is absorbed by the light absorber 19 and is not reflected to the viewer side. Therefore, the contrast of the image displayed on the transmissive screen 10 can be improved.

  In the description so far, the embodiment in which the Fresnel lens portion 23 includes the Fresnel lens layer 21 formed on the viewer side from the base portion 22 is described as an example. However, the Fresnel lens portion is formed on the image light source side from the base portion. May be. FIG. 6 is a vertical sectional view for explaining the layer structure of a transmission screen 10 ′ according to another embodiment. FIG. 6 is from the same viewpoint as FIG. The transmissive screen 10 ′ includes the Fresnel lens layer 21 ′ in place of the Fresnel lens layer 21 and is the same as the transmissive screen 10 except that the adhesive layer 25 is provided, and therefore, except for the Fresnel lens layer 21 ′ and the adhesive layer 25. Detailed description is omitted.

  The Fresnel lens layer 21 ′ is disposed on the light incident surface side of the multilayer body 11 and is preferably curved so as to be convex in the same direction as the multilayer body 11. The Fresnel lens layer 21 ′ includes a base portion 22 ′ and a Fresnel lens portion 23 ′ formed on the surface of the base portion 22 ′ on the image light source side.

  The base portion 22 'is a portion serving as a base for forming the Fresnel lens portion 23'. Accordingly, the base portion 22 'has a light-transmitting property and is configured to have a strength sufficient to form and hold the Fresnel lens portion 23'. The material and thickness constituting the base portion 22 ′ are the same as those of the base portion 22. The resin constituting the Fresnel lens portion 23 ′ is the same as that of the Fresnel lens portion 23.

  The Fresnel lens portion 23 ′ has a function of deflecting the traveling direction of the image light projected from the image light source 3 onto the transmissive screen 10 ′ as a divergent light beam. Specifically, the Fresnel lens unit 23 'converts the image light incident as a divergent light beam into a parallel light beam traveling from the image light incident side toward the image light emitting side, for example, a parallel light beam traveling in the front direction. In this way, by using the Fresnel lens portion 23 ′ to once convert the image light into a parallel luminous flux, the inner surface variation of the brightness of the image observed by the observer, particularly the image observed from the oblique direction by the observer is reduced. Can be effectively mitigated.

  The Fresnel lens portion 23 ′ is a so-called linear Fresnel lens, like the Fresnel lens portion 23, and includes a plurality of unit lenses 24 ′ that extend in one direction and are arranged in a direction different from the extending direction. Further, in the front view of the transmissive screen 10 ′, the direction in which the light transmitting portion 18 and the light absorbing portion 19 extend intersects with the direction in which the unit lens 24 ′ extends. As the cross-sectional shape of each unit lens 24 ′, a publicly known one can be used according to the purpose.

  As described above, by causing the direction in which the light transmitting portion 18 and the light absorbing portion 19 extend and the direction in which the unit lens 24 'extends to intersect, generation of moire can be suppressed as in the case of the transmission screen 10 described above. Further, from the viewpoint of suppressing the occurrence of moire, in the front view of the transmissive screen 10 ′, the direction in which the light transmitting portion 18 and the light absorbing portion 19 extend and the direction in which the unit lens 24 ′ extends (the ridgeline of the unit lens 24 ′ is The angle at which the extending direction intersects is preferably 3 ° or more and 10 ° or less, and more preferably 7 ° or more and 8 ° or less, similarly to the angle θ described above (see FIG. 4).

The image light emitted from the image light source 3 reaches the light incident surface side of the transmissive screen 10 ′, and the action of the Fresnel lens portion 23 ′ of the Fresnel lens layer 21 ′ as shown by the image lights L61 and L62 in FIG. Is deflected so as to be parallel to the observer side (front direction). The image light deflected in the Fresnel lens layer 21 ′ is transmitted through the base material layer 20, the light transmission part 18, the adhesive layer 16, the light diffusion layer 15, the adhesive layer 13 and the support 12, and is emitted to the observer side. The
On the other hand, at least a part of the external light (light from sunlight, room light, etc.) incident obliquely from above on the transmission screen 10 ′ from the observer side is absorbed by the light absorbing portion 19 and is not reflected to the observer side. Therefore, the contrast of the image displayed on the transmissive screen 10 ′ can be improved.

  The adhesive layer 25 is a layer containing an adhesive for adhering the Fresnel lens layer 21 ′ and the base material layer 20. The material used for the adhesive layer 25 is not particularly limited as long as it transmits light and can adhere the Fresnel lens layer 21 ′ and the base material layer 20. For the adhesive layer 25, for example, an ultraviolet curable resin or the like can be used.

  In the description so far, the light transmitting portion and the light absorbing portion of the optical functional layer extend horizontally, and the unit lens of the Fresnel lens layer has been described as an example extending in a direction inclined with respect to the horizontal. It is not limited to such a form. In the front view, the direction in which the light transmission part and the light absorption part extend and the direction in which the unit lens extends may cross each other. That is, the light transmitting portion and the light absorbing portion of the optical functional layer may extend in a direction inclined with respect to the horizontal, and the unit lens of the Fresnel lens layer may extend horizontally. The unit may extend in a direction inclined with respect to the horizontal, and the unit lens of the Fresnel lens layer may extend in a direction inclined with respect to the horizontal.

  In the description so far, the mode in which the light diffusion layer and the like are provided has been described as an example. However, the transmission screen may be provided with a known layer having another function. Examples of the other layer include a hard coat layer provided on the surface of the support (observer side surface), a light reducing layer provided between the optical functional layer and the support, and the like.

  Through the steps described below, a transmissive screen provided with an optical functional layer and a Fresnel lens layer was produced, and the presence or absence of moire was evaluated.

  First, an optical functional layer was formed on a base material layer made of polycarbonate as described above. The refractive index of the light transmission part was 1.55, and the refractive index of the light absorption part was 1.49. The dimensions of the parts constituting the optical functional layer are as shown in Table 1. The meaning of the characters shown in Table 1 is as shown in FIG. FIG. 7 is a view showing a part of a cross section in the thickness direction in the vertical direction of the optical functional layer. That is, P is the parallel pitch of the light transmitting portions, D is the depth of the light absorbing portion (size in the thickness direction of the optical function layer), W1 is the width of the light absorbing portion on the viewer side (vertical length), W2 is the width (vertical length) on the image light source side of the light absorber.

  Next, a non-curved support (polycarbonate plate) was prepared, and a sheet including the optical functional layer produced as described above was bonded to the laminate via an adhesive layer to produce a laminate. The laminated body was heated and softened, and further curved by vacuum forming to obtain a curved laminated body. In addition, the curvature of this curved laminated body is a curvature which becomes R1000 in the vertical direction.

  Next, a Fresnel lens layer including a linear Fresnel lens with a unit lens pitch of 112 μm was produced, and curved in the same manner as the curved laminate so as to be convex on the surface side where the linear Fresnel lens was formed. . A groove having a width as shown in Table 1 was formed in the center of the Fresnel lens provided in the Fresnel lens layer used here in parallel with the direction in which the unit lens extends. It is considered that the larger the groove width, the larger the pitch deviation of the unit lens. The “groove at the center of the Fresnel lens” shown in Table 1 is the width after the Fresnel lens layer is curved as described above.

  Further, when viewed from the front, the intersection θ (the bias angle θ in Table 1) between the direction (horizontal direction) in which the light transmitting portion and the light absorbing portion provided in the optical functional layer extend and the direction in which the unit lens provided in the Fresnel lens layer extends. The laminated body produced as described above and the Fresnel lens layer were laminated so that the value shown in Table 1 was obtained, and a transmission type screen was produced.

  As described above, a transmission screen was produced under the conditions shown in Table 1, and the presence or absence of moire was evaluated. Table 1 shows the results. In Table 1, “◯” means that moire did not occur, and “x” means that moire was generated so strongly that it could not be used as a transmission screen.

  As shown in Table 1, the occurrence of moire could be suppressed by setting the bias angle to 3 ° or more. However, when the bias angle was 13 °, there was a clear difference between the left and right viewing angles.

1 Rear projection display device (display device)
DESCRIPTION OF SYMBOLS 2 Case 3 Image | video light source 10 Transmission type screen 11 Laminated body 12 Support body 13 Adhesive layer 15 Light-diffusion layer 16 Adhesive layer 17 Optical function layer 18 Light transmission part 19 Light absorption part 20 Base material layer 21 Fresnel lens layer 22 Base 23 Fresnel Lens unit 24 Unit lens

Claims (3)

A transmissive screen having a portion curved so as to be convex on one surface side, displaying image by transmitting image light projected from one surface side to the other surface side,
A plurality of light transmitting portions that transmit light, which extend in one direction and are arranged in a direction different from the extending direction, and a light absorbing portion that absorbs light, formed between the adjacent light transmitting portions, An optical functional layer comprising:
A Fresnel lens layer that includes unit lenses that extend in one direction and are aligned in a direction different from the extending direction;
The transmission type screen in which the direction in which the light transmission part and the light absorption part extend intersects with the direction in which the unit lens extends in front view.   2. The transmissive screen according to claim 1, wherein an angle between a direction in which the light transmission unit and the light absorption unit extend and a direction in which the unit lens extends is 3 ° or more and 10 ° or less in a front view. An image light source that emits image light;
3. A display device comprising: the transmission screen according to claim 1, wherein the image light from the image light source is transmitted and emitted to an observer side.

Images