CN217213226U - Optical diffuser and optical module - Google Patents

Abstract

The utility model provides a light diffuser and optical module. The light diffuser includes: a base layer; the micro-lens array layer is arranged on at least one side surface of the substrate layer, a light ray outgoing surface is arranged on one side surface, away from the substrate layer, of the micro-lens array layer, and the micro-lens array layer comprises a plurality of micro-lenses; the glue layer is filled and arranged on one side, far away from the basal layer, of the micro-lens array layer, the micro-lens array layer is covered by the glue layer, and the refractive index of the glue layer is larger than that of the micro-lens array layer. The utility model provides a light diffuser among the prior art have the problem that efficiency is poor.

Description

Optical diffuser and optical module

Technical Field

The utility model relates to a three-dimensional imaging device technical field particularly, relates to a light diffuser and optical module.

Background

The current mode of realizing range finding in the industry mainly includes binocular, structured light and TOF, wherein binocular precision is lower, and structured light structure is complicated and the cost is higher, and TOF has sufficient precision and the cost is slightly lower, has had the trend of popularizing in popularity. TOF is usually composed of a transmitting end and a receiving end, wherein the transmitting end is mainly composed of a vcsel light source and an optical diffuser (diffuser). The structural configuration of the existing light diffuser is mainly in the form of a periodic array or a random array of microstructure units to realize the light field distribution. However, the optical diffuser in the prior art has the following problems:

1. when the surface with the lens structure is used as a light incidence surface, in order to enable the optical large angle to be larger than 120 degrees, the depth-to-width ratio (H _ pitch/rise H) of a single micro lens is larger than 1, the slope of the micro lens is larger than 65 degrees, and the detection equipment limit value on the market at the present stage is met.

2. When the lens structure surface is used as a light ray outgoing surface, because the refractive index of the structure surface is larger than that of air, the light ray outgoing surface is a curved surface structure, when the outgoing angle is larger than 120 degrees, the light ray can be pushed out according to Snell's law, and a part of light rays incident on the curved surface structure are larger than the total reflection angle, so that the light rays are continuously reflected in the light diffuser and cannot be emitted from the preset light ray outgoing surface, the efficiency of the light diffuser is reduced, the light beams are not controlled, and the light beam angle is reduced.

That is, the optical diffuser in the related art has a problem of poor efficiency.

SUMMERY OF THE UTILITY MODEL

A primary object of the present invention is to provide an optical diffuser and an optical module, which solve the problem of poor efficiency of the optical diffuser in the prior art.

In order to achieve the above object, according to one aspect of the present invention, there is provided a light diffuser including: a base layer; the micro-lens array layer is arranged on at least one side surface of the substrate layer, a light ray outgoing surface is arranged on one side surface, away from the substrate layer, of the micro-lens array layer, and the micro-lens array layer comprises a plurality of micro-lenses; the glue layer is filled and arranged on one side, far away from the basal layer, of the micro-lens array layer, the micro-lens array layer is covered by the glue layer, and the refractive index of the glue layer is larger than that of the micro-lens array layer.

Further, the surface of the side, away from the base layer, of the glue layer is a plane.

Further, the difference between the refractive indexes of the glue layer and the micro-lens array layer is greater than or equal to 0.2.

Further, the aspect ratio of the microlens is less than 0.6.

Furthermore, both side surfaces of the substrate layer are provided with the micro-lens array layers, and the structures of the micro-lens array layers on both sides are the same or different.

Further, the surface of the microlens is a free-form surface including a polynomial surface.

Furthermore, the plurality of microlenses of the microlens array layer are arranged in a periodic array, and the surface shape of each microlens is convex or concave.

Further, the length of the micro lens is more than or equal to 5um and less than or equal to 50 um; and/or the width of the micro lens is more than or equal to 5um and less than or equal to 50 um.

Further, the microlens includes one of a semi-ellipse, a semicircle, a triangle, and a trapezoid in a cross section perpendicular to the base layer.

According to the utility model discloses an on the other hand provides an optical module, include: a vcsel light source; in the optical diffuser, the vcsel light source is located on the side of the optical diffuser where the glue layer is not located, and is spaced from the optical diffuser, and the vcsel light source emits light to the optical diffuser.

By applying the technical scheme of the utility model, the light diffuser comprises a basal layer, a micro-lens array layer and a glue layer, at least one side surface of the basal layer is provided with the micro-lens array layer, one side surface of the micro-lens array layer, which is far away from the basal layer, is a light emergent surface, and the micro-lens array layer comprises a plurality of micro-lenses; the glue layer is filled and arranged on one side, far away from the basal layer, of the micro-lens array layer, the micro-lens array layer is covered by the glue layer, and the refractive index of the glue layer is larger than that of the micro-lens array layer.

Set up the glue layer through the one side of keeping away from the stratum basale at the microlens array layer, and the refracting index of glue layer is greater than the refracting index on microlens array layer, make the light of keeping away from one side incident on microlens array layer by the stratum basale behind the diffusion of microlens array layer, further diffusion outgoing through the glue layer again, make light can pass through two step diffusion, in order to realize the effect of light wide-angle outgoing, the angle scope of light diffuser has been enlarged, the application scenario has been increased, make the application of the light diffuser of this application more extensive. The glue layer shares the effect on light diffusion, so that the depth-to-width ratio of the micro lens does not need to be too high, the depth-to-width ratio of the micro lens is reduced, the surface type of the micro lens can meet the requirement of a device testing surface type, the surface type of the micro lens can be tested, accurate data of the surface type can be obtained, and the process has iterability. The refractive index through setting up the glue layer is greater than the refractive index on microlens array layer for light is when the surface on microlens array layer, is transmitted to high refractive index material from low refractive index material, thereby can avoid appearing the phenomenon of total reflection, avoid the condition of light constantly reflecting in microlens array layer, and then be favorable to guaranteeing most light in the light diffuser can exit smoothly, increased the extraction efficiency of light, improved light diffuser's result of use and efficiency. In addition, the micro lens array layer is covered by the glue layer, so that the glue layer can protect the micro lens array layer, the abrasion of the micro lens array layer in the packaging and transporting processes is avoided, and the use reliability of the micro lens array layer is ensured.

Drawings

The accompanying drawings, which form a part of the present application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 shows a schematic diagram of a prior art light diffuser;

fig. 2 shows a schematic structural diagram of an optical diffuser according to an alternative embodiment of the present invention;

FIG. 3 shows a simulated diagram of the optical path of the optical diffuser of FIG. 2;

FIG. 4 shows a graph of the light intensity distribution of the light diffuser of FIG. 2;

FIG. 5 shows an illuminance distribution plot of the light diffuser of FIG. 2;

fig. 6 shows a schematic structural diagram of an optical diffuser according to another alternative embodiment of the present invention;

fig. 7 shows a schematic structural view of a light diffuser according to another alternative embodiment of the present invention;

FIG. 8 illustrates a schematic diagram of a double-sided optical diffuser according to another alternative embodiment of the present invention;

FIG. 9 shows a simulated diagram of the optical path of the optical diffuser of FIG. 8;

FIG. 10 shows a graph of the light intensity distribution of the light diffuser of FIG. 8;

fig. 11 shows an illuminance distribution diagram of the light diffuser in fig. 8.

Wherein the figures include the following reference numerals:

10. a light diffuser; 11. a base layer; 12. a microlens array layer; 13. a glue layer; 20. a vcsel light source.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

It is noted that, unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

In the present application, where the contrary is not intended, the use of directional words such as "upper, lower, top and bottom" is generally with respect to the orientation shown in the drawings, or with respect to the component itself in the vertical, perpendicular or gravitational direction; likewise, for ease of understanding and description, "inner and outer" refer to the inner and outer relative to the profile of the components themselves, but the above directional words are not intended to limit the invention.

As shown in fig. 1, which is a schematic structural diagram of a single-sided light diffuser in the prior art, black arrows in the drawing indicate the transmission direction of light, when the surface of the microlens array layer is an emergent surface of light, since the angle of light incident on the surface of the microlens array layer is large (the inclination angle of the surface of the microlens array layer is large), according to snell's law, the refractive index of the microlens array layer is larger than that of air, so that the light is totally emitted on the surface of the microlens array layer, and is continuously reflected in the microlenses, and is finally consumed from the surface of the light incident side or inside the light diffuser, and cannot be emitted by a preset light emergent surface, and energy loss, loss of large-angle light, and finally the requirement of the light distribution angle range and the efficiency of the optical device cannot be met.

In order to solve the problem of poor efficiency of the optical diffuser 10 in the prior art, the present invention provides an optical diffuser 10 and an optical module.

As shown in fig. 2 to 11, the light diffuser 10 includes a substrate layer 11, a microlens array layer 12 and a glue layer 13, the microlens array layer 12 is disposed on at least one side surface of the substrate layer 11, a side surface of the microlens array layer 12 away from the substrate layer 11 is a light exit surface, and the microlens array layer 12 includes a plurality of microlenses; the glue layer 13 is filled in the side of the micro-lens array layer 12 far away from the substrate layer 11, the micro-lens array layer 12 is covered by the glue layer 13, and the refractive index of the glue layer 13 is larger than that of the micro-lens array layer 12.

Set up glue layer 13 through one side of keeping away from stratum basale 11 at microlens array layer 12, and glue layer 13's refracting index is greater than microlens array layer 12's refracting index, make the light of keeping away from one side incident of microlens array layer 12 by stratum basale 11 after microlens array layer 12 diffuses, further diffusion outgoing through glue layer 13 again, make light can pass through two step diffusion, in order to realize the effect of light wide-angle outgoing, the angle scope of light diffuser 10 has been enlarged, the application scene has been increased, make the application of the light diffuser 10 of this application more extensive. The glue layer 13 shares the function of light diffusion, so that the depth-to-width ratio of the micro lens does not need to be too high, the depth-to-width ratio of the micro lens is reduced, the micro lens surface can meet the requirement of an equipment testing surface type, the surface type of the micro lens can be tested, accurate data of the surface type can be obtained, and the process has iterability. The refractive index through setting up glue layer 13 is greater than the refractive index of microlens array layer 12, make light when microlens array layer 12's surface, be from low refractive index material to high refractive index material transmission, thereby can avoid appearing the phenomenon of total reflection, avoid the condition of light constantly reflecting in microlens array layer 12, and then be favorable to guaranteeing that most light in the light diffuser 10 can be emergent smoothly, the emergence efficiency of light has been increased, the result of use and the efficiency of light diffuser 10 have been improved. In addition, the micro lens array layer 12 is covered by the glue layer 13, so that the glue layer 13 can protect the micro lens array layer 12, abrasion of the micro lens array layer 12 in the packaging and transportation process is avoided, and the use reliability of the micro lens array layer 12 is ensured.

As shown in fig. 2, a surface of the glue layer 13 away from the substrate layer 11 is a plane, and a surface of the glue layer 13 away from the substrate layer 11 is higher than a surface of the microlens away from the substrate layer 11. The arrangement is favorable for protecting the micro-lens array layer 12 by the glue layer 13 and simultaneously is favorable for subsequent packaging and transportation work, so that the packaging and the transportation are more convenient. In addition, the surface of one side of the glue layer 13, which is far away from the substrate layer 11, is set to be a plane, so that light reaches the plane with high refractive index after being expanded through the two free-form surfaces, light is further refracted according to Snell's law, and the emergent light can reach the angle range of 180 degrees at most due to the fact that the emergent surface is a plane, and a large-angle emergent scheme is achieved.

Specifically, the difference between the refractive indices of the glue layer 13 and the microlens array layer 12 is 0.2 or more. Glue layer 13 adopts high refractive index material, and microlens array layer 12 adopts low refractive index material, does benefit to glue layer 13's surface like this and can further enlarge the exit angle of light to realize the effect of big angle outgoing, be favorable to increasing the light beam angle scope of light diffuser 10, make the light diffuser 10's of this application cover the angle scope wider, and then make the range of application more extensive. Note that the refractive index of the microlens array layer 12 is in the range of 1.4 to 1.6, and the refractive index of the glue layer 13 is in the range of 1.6 to 1.8.

Specifically, the aspect ratio of the single microlens of the present application is less than 0.6, and the aspect ratio is the ratio between the width and the height of the single microlens. Owing to set up the glue layer 13 that the refracting index is big, in order to expand beam transmission to the light, make glue layer 13 share the beam expanding effect to the light for microlens, the effect of big angle outgoing is realized to the microlens of this application need not too big aspect ratio, the aspect ratio of microlens has been reduced, the face type that is favorable to microlens reaches the requirement of equipment test face type, make the face type of microlens testable, can obtain the accurate data of face type, make the microlens of this application can be detected equipment test face type, and then analyze the face type deviation, be convenient for the improvement of microlens on the technology, be favorable to the iteration update of microlens.

Specifically, the surface of each microlens is a free-form surface, and the expression is as follows:

wherein Z is a rise of a plane parallel to the Z-axis direction; c is the curvature of the apex; k is a conic constant;

r is the radius value, Cjx ^m y ⁿ Is the jth free-form surface polynomial.

The free-form surface includes a polynomial surface. The polynomial surface is a 10 th order polynomial surface added on the basis of a conventional quadric surface, and the polynomial surface is expanded into x ^m y ⁿ Wherein m + n is less than or equal to 10. Cj is a single term x ^m y ⁿ Coefficient j ═ [ (m + n) ^2+ m +3n]/2+1；

When the coefficients Cj are positive, the free curved surface is a biconvex free curved surface, and the micro lens is a biconvex micro lens;

when the coefficients Cj are all negative, the free curved surface is a biconcave free curved surface, and the micro lens is a biconcave micro lens;

when the coefficients of the x items Cjx and Cjy are positive or negative, the free-form surface is a saddle surface, and the micro lens is a saddle micro lens.

The free-form surface is not an aspherical surface, and the degree of freedom is high. Generally, to simplify the design, free-form surface designs are often designed to be image-limited symmetric. However, a non-quadrant symmetric free-form surface designed by this principle is also within the scope of this patent.

Specifically, the microlenses of the microlens array layer 12 are arranged in a periodic array or a random array, the random array has random protection height and random size, adjacent microlenses are in smooth transition and are in seamless connection, the surface of each microlens is convex or concave, and preferably, the surface of one side of each microlens, which is far away from the substrate layer 11, is a convex free-form surface.

Specifically, the length and width dimensions of the entire free-form surface on the side of the microlens array layer 12 away from the base layer 11 are generally in the range of 1um to 1000 um. To realize the design of the thinner optical diffuser 10, ensuring lightness and thinness and miniaturization, the present application adopts the dimensions: the length of a single micro lens is more than or equal to 5um and less than or equal to 50 um; the width of the micro lens is greater than or equal to 5um and less than or equal to 50 um; preferably, the length and width dimensions of the individual microlenses are in the range of 10um to 30 um. The present application is not limited to the design of the light diffuser 10 of micron scale, but also includes the design of the lens of millimeter scale, centimeter scale, nanometer scale, etc.

As shown in fig. 3, which is a simulation diagram of an optical path of the single-sided light diffuser 10 of the present application, the vcsel light source 20 emits a 20 ° to 25 ° divergent angle light beam onto the light diffuser 10, and the light diffuser 10 expands the light beam to achieve a large-angle emission effect close to 180 °.

Fig. 4 shows the light intensity distribution at different angles of the single-sided light diffuser 10 of the present application. As can be seen, the half light intensity angles in the horizontal and vertical directions reach 130 degrees and 110 degrees, respectively.

Fig. 5 shows a distribution of illuminance of the single-sided optical diffuser 10 of the present application. As can be seen from the figure, the illuminance at each position of the finally formed light spot is uniform, and the situation of local over-dark or over-bright does not occur within the range of the diffusion angle of 130 × 110, so that better illuminance distribution is realized.

Specifically, the microlens includes one of a semi-ellipse, a semicircle, a triangle, and a trapezoid in a cross section perpendicular to the base layer 11. The shape of the plurality of microlenses of the microlens array layer 12 is not limited to the above-described shape. Fig. 6 is a schematic structural view of an optical diffuser 10 according to another alternative embodiment of the present invention, in which a plurality of microlenses are triangular in cross section perpendicular to a substrate layer 11. Fig. 7 is a schematic structural view of an optical diffuser 10 according to another alternative embodiment of the present invention, in which a plurality of microlenses are trapezoidal in cross section perpendicular to a substrate layer 11.

As shown in fig. 8, in an alternative embodiment, the microlens array layers 12 are disposed on both surfaces of the substrate layer 11, and the structures of the microlens array layers 12 on both sides may be the same or different. One of the two microlens array layers 12 is covered with a glue layer 13, the surface of one side of the microlens array layer 12, which is far away from the substrate layer 11, without the glue layer 13 is a light incident surface, the microlens array layers 12 on the two sides are made of low-refractive-index materials, and the glue layer 13 with high refractive index is arranged on a light emergent surface. The double-sided light diffuser 10 of the present embodiment is preferred, although a single-sided light diffuser 10 may also be desirable.

As shown in fig. 9, which is a simulation diagram of the optical path of the double-sided light diffuser 10 in fig. 8, the vcsel light source 20 emits 20 ° to 25 ° divergent angle light beams onto the light diffuser 10, and the light diffuser 10 expands the light beams to achieve the effect of emitting light beams at a large angle of up to 180 °.

Fig. 10 is a graph showing the light intensity distribution of the double-sided light diffuser 10 of fig. 8, in which the half light intensity angular distributions in the horizontal and vertical directions reach angular values of 150 degrees and 30 degrees.

As shown in fig. 11, which is an illuminance distribution diagram of the double-sided light diffuser 10 in fig. 8, according to application requirements, the illuminance diagram is a long-strip-shaped light spot, the horizontal direction is an angle value of 150 degrees with a large angle, and the vertical direction is an angle value of 30 degrees, and this design scheme is relatively easy to implement after the method of the present invention is adopted.

The light diffuser 10 of the present application is formed by imprinting a microlens array layer 12 having a low refractive index on a transparent glass or transparent plastic substrate layer 11, and then covering the microlens array layer 12 with a glue layer 13 having a high refractive index. The specific processing technology comprises the following steps:

glue homogenizing: coating photoresist on the tackified glass substrate layer 11 by using a photoresist homogenizer;

baking: baking under conventional conditions;

photoetching: selective exposure is carried out through laser direct writing;

and (3) developing: dissolving the unwanted photoresist with a developing solution;

and (3) embossing: mainly carrying out contraposition imprinting, and aligning the substrate layer 11 when carrying out structure imprinting;

and (3) storage: after the development is finished, the sample is placed in a sealed box and is kept in a hundred-grade drying cabinet;

iteration: after design output, multi-parameter verification is carried out, and fine adjustment is carried out through performance feedback.

The application also provides an optical module, the optical module includes the vcsel light source 20 and foretell light diffuser 10, the vcsel light source 20 can provide 20 to 25 divergence angle light beams, the vcsel light source 20 is located the one side that the light diffuser 10 does not set up glue layer 13, and set up with light diffuser 10 interval, the vcsel light source 20 is to light diffuser 10 emission light, the light diffuser 10 is used for carrying out the plastic to the light that the vcsel light source 20 emitted, reach the outgoing effect of wide-angle diffusion angle.

It should be noted that the optical module of this application can use in the artificial intelligence field of three-dimensional formation of image such as 3D sensing, face identification, machine vision, autopilot, and is concrete, can use in the TOF module.

It is obvious that the above described embodiments are only some of the embodiments of the present invention, and not all of them. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise, and it should be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the accompanying drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A light diffuser, comprising:

a base layer (11);

the micro-lens array layer (12) is arranged on at least one side surface of the substrate layer (11), the surface, away from the substrate layer (11), of one side of the micro-lens array layer (12) is a light ray outgoing surface, and the micro-lens array layer (12) comprises a plurality of micro-lenses;

the glue layer (13) is filled in the side, far away from the substrate layer (11), of the micro lens array layer (12), the micro lens array layer (12) is covered by the glue layer (13), and the refractive index of the glue layer (13) is larger than that of the micro lens array layer (12).

2. The light diffuser of claim 1, wherein a surface of the glue layer (13) facing away from the substrate layer (11) is planar.

3. The light diffuser of claim 1, wherein the difference between the refractive indices of the glue layer (13) and the microlens array layer (12) is equal to or greater than 0.2.

4. The light diffuser of claim 1, wherein said micro-lenses have an aspect ratio of less than 0.6.

5. The light diffuser of claim 1, wherein the microlens array layer (12) is disposed on both surfaces of the substrate layer (11), and the structures of the microlens array layers (12) on both sides are the same or different.

6. The light diffuser of claim 1, wherein the surface of the micro-lens is a free-form surface, the free-form surface comprising a polynomial surface.

7. The light diffuser of claim 1, wherein said plurality of said microlenses of said microlens array layer (12) are arranged in a periodic array, each said microlens having a convex or concave surface shape.

8. The light diffuser of claim 1,

the length of the micro lens is more than or equal to 5um and less than or equal to 50 um; and/or

The width of the micro lens is greater than or equal to 5um and less than or equal to 50 um.

9. The light diffuser of any one of claims 4 to 8, wherein the micro-lenses comprise one of semi-elliptical, semi-circular, triangular, trapezoidal in a cross-section perpendicular to the substrate layer (11).

10. An optical module, comprising:

a vcsel light source (20);

the optical diffuser (10) of any one of claims 1 to 9, said vcsel light source (20) being located on a side of said optical diffuser (10) not provided with a glue layer (13) and spaced from said optical diffuser (10), said vcsel light source (20) emitting light towards said optical diffuser (10).

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