CN217181265U - Light uniformizing sheet and optical device - Google Patents

Abstract

The utility model provides a dodging piece and optical device. The light homogenizing sheet comprises: a base layer; the Fresnel layer is arranged on the surface of one side of the base layer, and the surface, away from the base layer, of one side of the Fresnel layer is an incident surface; the micro-lens array layer is arranged on the other side surface of the substrate layer, one side surface, far away from the substrate layer, of the micro-lens array layer is an exit surface, the micro-lens array layer comprises a plurality of micro-lenses, the projections of the micro-lenses on the substrate layer are polygonal, the heights of the micro-lenses are the same or different, and at least two micro-lenses are arranged in the first direction and the second direction which are perpendicular to each other. The utility model provides an even light piece among the prior art have the inhomogeneous problem of formation of image luminance.

Description

Light uniformizing sheet and optical device

Technical Field

The utility model relates to a diffraction optics technical field particularly, relates to an even light piece and optical device.

Background

The types of optical devices in the prior art are various, and taking the HUD head-up display system as an example, the HUD head-up display system is one of the important components of the close network connection established by integrating the environmental sensor of the driver assistance system, the GPS data, the map data, and the driving dynamic data. The integration of AR (augmented reality) technology into HUDs is currently the most popular AR HUD. Compared with the conventional W HUD, the AR HUD has a larger virtual image distance VID (VID > 7.5m, even infinity), a larger field angle FOV (FOV > 10 ° by 3 °), a larger virtual image size (tens of inches), and the virtual image can cover multiple lanes and merge with the image of the traffic environment in front.

The volume production of present HUD is still mainly W HUD, but through the technological accumulation for many years, AR HUD also begins to move towards the volume production: since the release of new cars by some mainstream car manufacturers in the last year, relevant car models of AR HUDs are continuously marketed by all manufacturers. As one of the core configurations of automobile intellectualization, at the next time, the AR HUD will become a common configuration of automobile enterprises in the field of intelligent automobiles, and the market will rapidly develop. However, the dodging sheet adopted by the AR HUD in the prior art is generally designed as a single-sided microlens, light beams emitted by a light source are obliquely incident when entering the edge of the dodging sheet, have a certain incident angle, and form an optical field which is asymmetrically distributed after being diffused by the dodging sheet, and the optical field is different from an optical field formed by central light beams of the dodging sheet. The light spot of the central light field is in the center of the receiving surface, the uniformity is good, the light spot of the left light field is not in the center of the receiving surface, the uniformity is not good, and the uneven conditions that the left side is brighter, the right side is darker or the right side is brighter and the left side is darker are easy to occur.

That is, the light uniformizing sheet in the prior art has a problem of non-uniform imaging brightness.

SUMMERY OF THE UTILITY MODEL

The main object of the utility model is to provide an even light piece and optical device to there is the inhomogeneous problem of formation of image luminance in the even light piece of solving among the prior art.

In order to achieve the above object, according to an aspect of the present invention, there is provided a light uniformizing sheet including: a base layer; the Fresnel layer is arranged on the surface of one side of the base layer, and the surface, away from the base layer, of one side of the Fresnel layer is an incident surface; the micro-lens array layer is arranged on the other side surface of the substrate layer, one side surface, far away from the substrate layer, of the micro-lens array layer is an exit surface, the micro-lens array layer comprises a plurality of micro-lenses, the projections of the micro-lenses on the substrate layer are polygonal, the heights of the micro-lenses are the same or different, and at least two micro-lenses are arranged in the first direction and the second direction which are perpendicular to each other.

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

Further, when the heights of the microlenses are the same, the projection of each microlens on the substrate layer is quadrilateral, and the microlenses are arranged periodically.

Further, the quadrangle includes a square or a rectangle.

Further, when the heights of the microlenses are different, the distances between the vertexes of at least some of the microlenses and the substrate layer are not equal, and the projection shapes of at least some of the microlenses on the substrate layer are different.

Further, the Fresnel layer at least comprises a tooth structure and a convex hull structure, the tooth structure is arranged on the periphery of the convex hull structure, the tooth structure is annular and is multiple, and the plurality of annular tooth structures are arranged at intervals along the direction away from the convex hull structure.

Furthermore, the heights of the tooth structures are the same, and the height of each tooth structure is less than or equal to 60 um; and/or a plurality of tooth structures are arranged at equal intervals; and/or the distance between two adjacent tooth structures is less than or equal to 60 um.

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; and/or the height of the microlens is 0um or more and 20um or less.

Further, the material refractive index N of the microlens satisfies: 1< N < 5.

According to another aspect of the present invention, there is provided an optical apparatus, comprising: the light homogenizing sheet; the light source and the light homogenizing sheet are arranged at intervals, and the light source is positioned on one side of the light homogenizing sheet with the Fresnel layer.

By applying the technical scheme of the utility model, the light homogenizing sheet comprises a basal layer, a Fresnel layer and a micro-lens array layer, the Fresnel layer is arranged on one side surface of the basal layer, and one side surface of the Fresnel layer far away from the basal layer is an incident surface; the micro-lens array layer is arranged on the other side surface of the substrate layer, one side surface, far away from the substrate layer, of the micro-lens array layer is an exit surface, the micro-lens array layer comprises a plurality of micro-lenses, projections of the micro-lenses on the substrate layer are polygonal, the heights of the micro-lenses are the same or different, and at least two micro-lenses are arranged in the first direction and the second direction which are perpendicular to each other.

Through setting up the stratum basale for the stratum basale provides the basis that sets up for fei nieer layer and microlens array layer, is favorable to improving the use reliability on fei nieer layer and microlens array layer, guarantees the holistic structural stability of even slide simultaneously. The incident surface is the Fresnel layer, so that incident light can be collimated and emitted after passing through the Fresnel layer, and then the collimated light is diffused to a required angle and emitted after passing through the micro-lens array layer. This application is even slide of two-sided design, and one side is fei nieer layer, and the another side is microlens array layer, makes the light of external light source transmission obtain the even unanimous light field facula of left side right 3 luminance in the receiving face behind fresnel layer, the microlens array layer in proper order through two-sided design to guarantee the homogeneity of final formation of image. By reasonably planning the arrangement mode, the shape and the height of a plurality of microlenses on the microlens array layer, the performance stability of the microlens array layer is favorably improved, and light field light spots without dark stripes, water-free ripples, rainbow stripes, good granular sensation and fine and smooth pictures are favorably obtained.

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 optical path diagram of an optical device according to an alternative embodiment of the present invention;

FIG. 2 shows a schematic view of the side of the dodging sheet of FIG. 1 having a microlens array layer;

FIG. 3 shows a schematic view of the side of the light integrator of FIG. 1 having the Fresnel layer;

FIG. 4 shows a cross-sectional view of the shim of FIG. 1;

FIG. 5 shows a simulated view of one angle of the Fresnel layer;

fig. 6 shows a simulated view of the central light field of an optical device according to an alternative embodiment of the invention;

FIG. 7 shows a schematic view of an angle of a random array of microlens arrays;

FIG. 8 shows a schematic view of another angle of a random array of microlens arrays;

fig. 9 shows a schematic diagram of an optical path of an optical device in the prior art.

Wherein the figures include the following reference numerals:

10. a light source; 20. a receiving surface; 30. a microlens array layer; 40. a Fresnel layer; 41. a tooth structure; 42. and (4) a convex hull structure.

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. 9, which is a schematic diagram of an optical path of a light homogenizing sheet in the prior art, it can be known that the structural configuration of the prior light homogenizing sheet mainly adopts a design of a single-sided random microlens array, and when the random microlens array is at an incident surface, a laser beam emitted by an external light source 10 is obliquely incident when being incident on the edge of the light homogenizing sheet, and has a certain incident angle, and an optical field after being diffused by the light homogenizing sheet is asymmetrically distributed, which is different from an optical field of a central light beam of the light homogenizing sheet. The central light field light spot is in the center of the receiving surface 20, the uniformity is good, the left light field light spot is not in the center of the receiving surface 20, the uniformity is not good, and the left side is brighter and the right side is darker; the light spot of the right light field is not in the center of the receiving surface 20, and the uniformity is not good, so that the right side is brighter and the left side is darker. So that the brightness of the left, middle and right 3 light field spots on the final receiving surface 20 is not uniform, which affects the imaging effect.

In order to solve the problem that the uniform light sheet in the prior art has uneven imaging brightness, the utility model provides a uniform light sheet and optical device.

As shown in fig. 1 to 8, the dodging sheet includes a base layer, a fresnel layer 40 and a microlens array layer 30, the fresnel layer 40 is disposed on one side surface of the base layer, and one side surface of the fresnel layer 40 away from the base layer is an incident surface; the microlens array layer 30 is disposed on the other side surface of the substrate layer, the surface of the microlens array layer 30 away from the substrate layer is an exit surface, the microlens array layer 30 includes a plurality of microlenses, the projection of each microlens on the substrate layer is polygonal, the heights of the microlenses are the same or different, and at least two microlenses are disposed in the first direction and the second direction perpendicular to each other.

Through setting up the stratum basale for the stratum basale provides the setting basis for fresnel layer 40 and microlens array layer 30, is favorable to improving fresnel layer 40 and microlens array layer 30's use reliability, guarantees the holistic structural stability of even slide simultaneously. By arranging the Fresnel layer 40 as the incident surface, the incident light can be collimated and emitted after passing through the Fresnel layer 40, and then the collimated light is diffused through the micro-lens array layer 30 and emitted at a required angle. This application is even slide of two-sided design, and one side is fresnel layer 40, and the another side is microlens array layer 30, makes the light of external light source 10 transmission pass through fresnel layer 40, microlens array layer 30 back in proper order through two-sided design and obtains the even unanimous light field facula of 3 luminance in the left and right sides at receiving face 20 to guarantee the homogeneity of final formation of image. By reasonably planning the arrangement mode, shape and height of a plurality of microlenses on the microlens array layer 30, the performance stability of the microlens array layer 30 is favorably improved, and light field light spots without dark stripes, water ripples, rainbow stripes, good granular sensation and fine and smooth pictures are favorably obtained.

Specifically, the surface of the microlens is a free-form surface or a polynomial surface.

When the surface of the microlens is a free curved surface, the free curved surface satisfies the following formula:

when the surface of the micro lens is a polynomial curved surface, the polynomial curved surface is a 10-order polynomial curved surface added on the basis of a conventional quadric surface, the polynomial is expanded into a monomial expression of x ^ my ^ n, wherein m + n is less than or equal to 10; k is a conic constant; c is curvature;

cj is the coefficient j ^ m + n ^2+ m +3n ]/2+1 of the single term x ^ my ^ n;

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, it is within the scope of this patent to design a free-form surface that is not quadrant symmetric from this principle. In addition, the surface type of the microlens of the present application includes one of a convex surface and a concave surface, and is preferably a convex free-form surface.

Specifically, the microlens array layer 30 may employ a periodic array or a random array.

As shown in fig. 1 to 4, in an alternative embodiment of the present application, when the heights of the plurality of microlenses are the same, the projection of each microlens on the substrate layer is quadrilateral, and the plurality of microlenses are arranged periodically. The quadrilateral comprises a square or rectangle, preferably a square. As shown in fig. 2, there is shown a side of the light homogenizing plate having a microlens array layer 30, a plurality of microlenses are arranged on the substrate layer in a periodic array, and a plurality of microlenses are respectively arranged in a first direction and a second direction perpendicular to each other, and the first direction is parallel to at least one side of the substrate layer, and the second direction is parallel to at least one side of the substrate layer. The sizes and heights of the microlenses are the same in the figure.

In another alternative embodiment of the present application, the microlens array layer 30 is preferably a random array, as shown in fig. 7 and 8. When the heights of the microlenses are different, the distances between the vertexes of at least part of the microlenses and the substrate layer are not equal, and the projection shapes of at least part of the microlenses on the substrate layer are different. As shown in fig. 7, the bottom of the plurality of microlenses is not flush, and the top of the plurality of microlenses is also not flush, to form a highly random microlens array layer 30. As shown in fig. 8, the random distribution in the XY horizontal plane shows that the projection shapes of the plurality of microlenses on the basal layer are different from each other, the projection shapes of the microlenses on the basal layer include a plurality of types of quadrangle, pentagon, and hexagon, and the sizes of the respective lenses are different from each other. Diffraction and interference diffraction fringes can be eliminated through the micro lens with randomly arranged XYZ positions and sizes, and the final imaging effect is more uniform. By means of random XYZ positions and sizes, the grain appearance can be eliminated, rainbow stripes can be eliminated, water ripples formed in photoetching and nano-imprinting processes can be eliminated, zero-order stripes of diffraction centers can be eliminated, and the final imaging effect is more uniform.

Specifically, when the projection of the micro lens on the substrate layer is rectangular, 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 each single micro lens is greater than or equal to 5um and less than or equal to 50 um; the height of the single microlens is equal to or greater than 0um and equal to or less than 20 um. Preferably, the length of the single microlens is equal to or greater than 10um and equal to or less than 30 um; the width of each single micro lens is greater than or equal to 10um and less than or equal to 30 um; the height of the single microlens is 5um or more and 15um or less. Through the size of reasonable restraint microlens, be favorable to guaranteeing the rationality of microlens size, guarantee the processing convenience of microlens simultaneously. The surface of one side of the micro lens, which is far away from the substrate layer, is a free-form surface, the free-form surface can eliminate phase difference, the degree of freedom is high, and arbitrary optical illumination distribution can be realized. While adjacent microlenses are smoothly transitioned through a free-form surface to increase manufacturing feasibility.

In an alternative embodiment, the side length of the microlens array layer 30 is in the range of 10um to 30um, although this can be adjusted as the case may be.

As shown in fig. 1 to 6, the fresnel layer 40 at least includes a tooth structure 41 and a convex hull structure 42, the tooth structure 41 is disposed on the periphery of the convex hull structure 42, the tooth structure 41 is annular and is plural, and the plural annular tooth structures 41 are spaced apart from each other in a direction away from the convex hull structure 42. As shown in fig. 3, the plurality of tooth structures 41 adjacent to the convex hull structure 42 are circular ring-shaped, and the tooth structure 41 of the edge portion is not circular ring-shaped but is a part of a circular ring.

Specifically, the fresnel layer 40 may be designed to have an equal height, that is, the height of each tooth structure 41 is the same as that of the convex hull structure 42, and the height of each tooth structure 41 is less than or equal to 60 um; or the fresnel layer 40 may be designed to have an equal width, that is, a plurality of tooth structures 41 are arranged at equal intervals, and the distance between two adjacent tooth structures 41 is less than or equal to 60 um. Preferably, the Fresnel layer 40 is of constant width design. The arrangement is favorable for solving the Fresnel lines and the Moire fringes and ensuring the final imaging effect.

Specifically, the substrate layer is made of transparent optical materials such as glass, silica gel, polymer materials and the like. The upper and lower microlens array layers 30 and the fresnel layer 40 are generally made of soft materials by nanoimprint lithography, and are usually made of silica gel, polymer materials, and the like. Material refractive index range of microlens: 1< N <5, each optical material has a refractive index, and optical distribution in a desired direction can be obtained according to the law of refraction through the refractive index and the curvature of a surface type, so that illumination of a certain target can be obtained. The light homogenizing sheet can be realized by stamping, injection molding, machining and other processes. Plastic injection molding is a method for processing plastic products, wherein molten plastic is injected into a plastic product mold by pressure, and various plastic parts are obtained by cooling and molding. The material used for optical products is typically PC or PMMA. The microlens mainly produced by the process has larger size, generally the size is above millimeter.

In addition, the nanoimprint technology is a novel micro-nano processing technology. The technology achieves ultrahigh resolution by means of mechanical transfer, is expected to replace the traditional photoetching technology in the future, and becomes an important processing means in the fields of microelectronics and materials. The nano-imprinting technology is a technology for transferring a micro-nano structure on a template to a material to be processed by assistance of photoresist. The nanoimprint technique is divided into three steps. The first step is the processing of the template. Generally, electron beam lithography is used to process a desired structure on a silicon or other substrate as a template. Since the diffraction limit of electrons is much smaller than that of photons, much higher resolution than lithography can be achieved. The second step is the transfer of the pattern. Coating photoresist on the surface of a material to be processed, pressing a template on the surface of the material, and transferring the pattern onto the photoresist in a pressurizing mode. Note that the photoresist cannot be completely removed, preventing the template from coming into direct contact with the material, damaging the template. The third step is the processing of the substrate. And curing the photoresist by using ultraviolet light, removing the template, etching the photoresist which is not completely removed in the previous step by using etching liquid to expose the surface of the material to be processed, then processing by using a chemical etching method, and removing all the photoresist after the processing is finished to finally obtain the material processed with high precision. Since the nanoimprint technology does not use visible light or ultraviolet light to process patterns, but uses mechanical means to transfer patterns, the method can achieve high resolution. The highest resolution can reach 2 nanometers. In addition, the template can be used repeatedly, thereby undoubtedly greatly reducing the processing cost and effectively shortening the processing time. Therefore, the nanoimprint technology has the technical advantages of ultrahigh resolution, easiness in mass production, low cost and high consistency, and is considered as a processing means which is expected to replace the existing photoetching technology.

The machining method is to machine the microlens structure on the mold by a machine tool, and may be to machine the microlens structure on the transparent material by laser marking.

As shown in fig. 1, the optical device includes the above light uniformizing sheet and the light source 10, the light source 10 and the light uniformizing sheet are disposed at an interval, and the light source 10 is located at one side of the light uniformizing sheet having the fresnel layer 40. In the present application, the light source 10 is a laser light source 10. As shown in the figure, the laser beam is collimated and emitted after passing through the fresnel layer 40, and then is diffused and emitted to the receiving surface 20 through the micro-lens array layer 30 to form a left light field, a central light field and a right light field, and the brightness of the 3 light fields is uniform, and the imaging picture is clear. As shown in fig. 6, a simulated view of the central light field obtained at the receiving surface 20 by using the fresnel layer 40 of the same width design, it can be seen that the light field is uniform in brightness,

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 drawings described above 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 unifying sheet comprising:

a base layer;

the Fresnel layer (40) is arranged on one side surface of the base layer, and one side surface, far away from the base layer, of the Fresnel layer (40) is an incident surface;

the micro-lens array layer (30) is arranged on the other side surface of the substrate layer, one side surface, away from the substrate layer, of the micro-lens array layer (30) is an exit surface, the micro-lens array layer (30) comprises a plurality of micro-lenses, the projection of each micro-lens on the substrate layer is polygonal, the heights of the micro-lenses are the same or different, and at least two micro-lenses are arranged in a first direction and a second direction which are perpendicular to each other.

2. The light uniformizing sheet according to claim 1, wherein the surface of the micro lens is a free-form surface or a polynomial surface.

3. The light homogenizing sheet according to claim 1, wherein when the heights of the plurality of micro lenses are the same, the projection of each micro lens on the substrate layer is quadrilateral, and the plurality of micro lenses are arranged periodically.

4. The plectrum of claim 3, wherein the quadrilateral comprises a square or a rectangle.

5. The light homogenizing sheet according to claim 1, wherein when the heights of the plurality of micro lenses are different, the distances between the vertexes of at least some of the micro lenses and the substrate layer are not equal, and the projection shapes of at least some of the micro lenses on the substrate layer are not the same.

6. A light distributing sheet according to claim 1, wherein the fresnel layer (40) comprises at least a tooth structure (41) and a convex hull structure (42), the tooth structure (41) is disposed on the periphery of the convex hull structure (42), the tooth structure (41) is annular and plural, and the plural annular tooth structures (41) are spaced apart in a direction away from the convex hull structure (42).

7. The light uniformizing sheet according to claim 6,

the heights of the tooth structures (41) are the same, and the height of each tooth structure (41) is less than or equal to 60 um; and/or

A plurality of the tooth structures (41) are arranged at equal intervals; and/or

The distance between two adjacent tooth structures (41) is less than or equal to 60 um.

8. The light uniformizing sheet according to 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; and/or

The height of the micro lens is greater than or equal to 0um and less than or equal to 20 um.

9. A dodging sheet according to any one of claims 1 to 4, wherein the material refractive index N of the microlenses is such that: 1< N < 5.

10. An optical device, comprising:

the light unifying sheet of any one of claims 1 to 9;

the light source (10), the light source (10) with even light piece interval sets up, and light source (10) are located even light piece has fresnel layer (40) one side.

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