阅读说明：本技术 光波导结构和显示装置 (Optical waveguide structure and display device ) 是由 尹正坤 陈远 汪杰 孙理斌 明玉生 于 2021-09-06 设计创作，主要内容包括：本发明提供了一种光波导结构和显示装置。光波导结构包括：光波导片；耦入光栅,耦入光栅设置在光波导片上,耦入光栅将外部光源组件发出的光耦入光波导片内；转折光栅,转折光栅用于接收耦入光栅的光；耦出光栅,耦出光栅用于接收转折光栅的光；匀光膜层,匀光膜层为一个或多个,且转折光栅和耦出光栅中的至少一个上设置有匀光膜层,匀光膜层具有多个匀光区,多个匀光区中的至少两个匀光区的厚度和/或材料不同,以使各匀光区对光的匀光效果不同。本发明解决了现有技术中的光波导结构存在显示效果不均匀的问题。(The invention provides an optical waveguide structure and a display device. The optical waveguide structure includes: an optical waveguide sheet; the coupling-in grating is arranged on the optical waveguide sheet and couples light emitted by the external light source component into the optical waveguide sheet; a turning grating for receiving light coupled into the grating; the coupling-out grating is used for receiving the light of the turning grating; the light homogenizing film layer is arranged on at least one of the turning grating and the coupling-out grating and is provided with a plurality of light homogenizing regions, and the thicknesses and/or materials of at least two light homogenizing regions in the light homogenizing regions are different, so that the light homogenizing effects of the light homogenizing regions on the light are different. The invention solves the problem of uneven display effect of the optical waveguide structure in the prior art.)

1. An optical waveguide structure, comprising:

an optical waveguide sheet;

the incoupling grating (10), the said incoupling grating (10) is set up on the said optical waveguide sheet, the said incoupling grating (10) couples the light that the external light source assembly sends into the said optical waveguide sheet;

a turning grating (20), the turning grating (20) being adapted to receive light coupled into the grating (10);

an outcoupling grating (30), the outcoupling grating (30) being adapted to receive light of the turning grating (20);

the light homogenizing film layer (40) is arranged on at least one of the turning grating (20) and the coupling-out grating (30), the light homogenizing film layer (40) is provided with a plurality of light homogenizing areas, and the thicknesses and/or materials of at least two of the light homogenizing areas are different, so that the light homogenizing effects of the light homogenizing areas on the light are different.

2. Optical waveguide structure according to claim 1, characterized in that the turning grating (20) has a plurality of sub-turning grating regions (21), the outcoupling grating (30) has a plurality of sub-outcoupling grating regions (31),

the light homogenizing film layer (40) is arranged on the turning grating (20) and a plurality of light homogenizing areas of the light homogenizing film layer (40) correspond to at least part of the sub-turning grating areas (21) one by one; and/or

The light homogenizing film layer (40) is arranged on the coupling-out grating (30) and the light homogenizing regions of the light homogenizing film layer (40) correspond to at least part of the sub-coupling-out grating regions (31) one by one.

3. The optical waveguide structure of claim 2,

the turning grating (20) is positioned at one side of the coupling-in grating (10), the coupling-out grating (30) is positioned at one side of the turning grating (20), and a connecting line of the center of the coupling-in grating (10) and the center of the turning grating (20) is vertical to a connecting line of the center of the coupling-out grating (30) and the center of the turning grating (20); and/or

A plurality of sub-turning grating regions (21) are arranged in sequence along a first direction (60), a plurality of sub-coupling grating regions (31) are arranged in sequence along a second direction (70), an included angle is formed between the first direction (60) and the second direction (70), and the included angle is an acute angle or a right angle.

4. An optical waveguide structure according to claim 3, characterized in that another said light homogenizing film layer (40) is disposed on said incoupling grating (10), said incoupling grating (10) is divided into a plurality of sub-incoupling grating regions along said first direction (60), and a plurality of said light homogenizing regions of another said light homogenizing film layer (40) are in one-to-one correspondence with at least part of said sub-incoupling grating regions.

5. The optical waveguide structure of claim 3,

the thickness of the even light area on one side of the turning grating (20) close to the coupling-in grating (10) is larger than that on one side of the turning grating (20) far away from the coupling-in grating (10); and/or

The thickness of the even light area on the side of the coupling-out grating (30) close to the turning grating (20) is larger than that on the side of the coupling-out grating (30) far away from the turning grating (20).

6. The optical waveguide structure of claim 2,

the thickness of the light homogenizing area of the light homogenizing film layer (40) on the turning grating (20) is gradually reduced along the direction far away from the coupling-in grating (10); and/or

The thickness of the dodging area of the dodging film layer (40) on the coupling-out grating (30) is gradually reduced along the direction far away from the turning grating (20).

7. The optical waveguide structure of claim 1,

the turning grating (20) is a one-dimensional grating or a two-dimensional grating; and/or

The coupling-out grating (30) is a one-dimensional grating or a two-dimensional grating;

the one-dimensional grating is one of a rectangular grating, an inclined grating, a step grating and a blazed grating, and the two-dimensional grating is one of a cylindrical grating and a pyramidal grating.

8. The optical waveguide structure of claim 1,

the thickness of the uniform light film layer (40) is more than or equal to 10 nanometers and less than or equal to 2 micrometers; and/or

The refractive index of the uniform light film layer (40) is more than or equal to 1.4 and less than or equal to 4.9.

9. The optical waveguide structure of claim 1 wherein the material of the homogenizing zone comprises one of silicon dioxide, doped silicon dioxide, silicon nitride, silicon oxynitride, cerium dioxide, aluminum oxide, tantalum pentoxide, beryllium oxide, calcium fluoride, cerium fluoride, chromium fluoride, lanthanum fluoride, strontium fluoride, ytterbium fluoride, silicon, doped silicon, titanium dioxide, chromium dioxide, aluminum oxide, tantalum pentoxide, aluminum oxynitride, germanium, doped germanium, hafnium oxide, magnesium oxide, neodymium oxide, praseodymium oxide, scandium oxide, zinc selenide, zinc sulfide, and zirconium oxide.

10. A display device, comprising:

a light source assembly;

the optical waveguide structure of any one of claims 1 to 9, the light source assembly emitting light into the optical waveguide structure, the optical waveguide structure coupling out the light into a human eye.

Technical Field

The invention relates to the technical field of diffraction optical equipment, in particular to an optical waveguide structure and a display device.

Background

With the development of society and continuous innovation of technology, Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR) have gradually entered into people's lives, wherein in the AR augmented reality aspect, optical waveguide technology is an indispensable step, and the performance requirements of gratings, as the main coupling-in, turning-over, and coupling-out elements in the mainstream design scheme of the current optical waveguide, are very strict. At present, the grating has high efficiency and good angle uniformity under the whole field angle, so that the light with different field angles is difficult to balance to a uniform and efficient effect, and the transmission paths of the light with different wavelengths in the optical waveguide are different at different field angles, so that the efficiency distribution is uneven when the light reaches the human eyes.

With the development of micro-nano processing technology, although some partition modulation can be achieved at present to realize the function of adjusting the display uniformity, most of the modulation modes at present adopt different grating duty ratio modulation, grating height modulation, inclined grating inclination angle modulation and grating appearance partition modulation. However, these methods all produce a great deal of complexity in plate making, and have a great influence on the processing cost and the process difficulty.

That is, the optical waveguide structure in the related art has a problem of non-uniform display effect.

Disclosure of Invention

The invention mainly aims to provide an optical waveguide structure and a display device, and aims to solve the problem that the display effect of the optical waveguide structure in the prior art is not uniform.

In order to achieve the above object, according to one aspect of the present invention, there is provided an optical waveguide structure comprising: an optical waveguide sheet; the coupling-in grating is arranged on the optical waveguide sheet and couples light emitted by the external light source component into the optical waveguide sheet; a turning grating for receiving light coupled into the grating; the coupling-out grating is used for receiving the light of the turning grating; the light homogenizing film layer is arranged on at least one of the turning grating and the coupling-out grating and is provided with a plurality of light homogenizing regions, and the thicknesses and/or materials of at least two light homogenizing regions in the light homogenizing regions are different, so that the light homogenizing effects of the light homogenizing regions on the light are different.

Furthermore, the turning grating is provided with a plurality of sub-turning grating regions, the coupling grating is provided with a plurality of sub-coupling grating regions, the light homogenizing film layer is arranged on the turning grating, and the plurality of light homogenizing regions of the light homogenizing film layer correspond to at least part of the sub-turning grating regions one by one; and/or the light homogenizing film layer is arranged on the coupling-out grating, and the plurality of light homogenizing areas of the light homogenizing film layer correspond to at least part of the sub-coupling-out grating areas one by one.

Furthermore, the turning grating is positioned at one side of the coupling grating, the coupling grating is positioned at one side of the turning grating, and the connecting line of the center of the coupling grating and the center of the turning grating is vertical to the connecting line of the center of the coupling grating and the center of the turning grating; and/or the sub-turning grating regions are sequentially arranged along a first direction, the sub-coupling grating regions are sequentially arranged along a second direction, and an included angle is formed between the first direction and the second direction and is an acute angle or a right angle.

Furthermore, another light homogenizing film layer is arranged on the coupling-in grating, the coupling-in grating is divided into a plurality of sub coupling-in grating regions along the first direction, and the plurality of light homogenizing regions of the other light homogenizing film layer correspond to at least part of the sub coupling-in grating regions one to one.

Further, the thickness of the even light area on one side of the turning grating close to the coupling-in grating is larger than that on one side of the turning grating far away from the coupling-in grating; and/or the thickness of the even light area on one side of the coupling grating close to the turning grating is larger than that on one side of the coupling grating far away from the turning grating.

Furthermore, the thickness of the dodging area of the dodging film layer on the turning grating is gradually reduced along the direction far away from the coupled grating; and/or the thickness of the even light area of the even light film layer on the coupling grating is gradually reduced along the direction far away from the turning grating.

Furthermore, the turning grating is a one-dimensional grating or a two-dimensional grating; and/or the coupled-out grating is a one-dimensional grating or a two-dimensional grating; the one-dimensional grating is one of a rectangular grating, an inclined grating, a step grating and a blazed grating, and the two-dimensional grating is one of a cylindrical grating and a pyramidal grating.

Further, the thickness of the light homogenizing film layer is more than or equal to 10 nanometers and less than or equal to 2 micrometers; and/or the refractive index of the light homogenizing film layer is more than or equal to 1.4 and less than or equal to 4.9.

Further, the material of the light uniformizing region includes one of silicon dioxide, doped silicon dioxide, silicon nitride, silicon oxynitride, cerium dioxide, aluminum oxide, tantalum pentoxide, beryllium oxide, calcium fluoride, cerium fluoride, chromium fluoride, lanthanum fluoride, strontium fluoride, ytterbium fluoride, silicon, doped silicon, titanium dioxide, chromium dioxide, aluminum oxide, tantalum pentoxide, aluminum oxynitride, germanium, doped germanium, hafnium oxide, magnesium oxide, neodymium oxide, praseodymium oxide, scandium oxide, zinc selenide, zinc sulfide, and zirconium oxide.

According to another aspect of the present invention, there is provided a display apparatus including a light source assembly; in the optical waveguide structure, the light source assembly emits light to the optical waveguide structure, and the optical waveguide structure couples the light out to human eyes.

By applying the technical scheme of the invention, the optical waveguide structure comprises an optical waveguide sheet, an in-coupling grating, a turning grating, an out-coupling grating and a light homogenizing film layer, wherein the in-coupling grating is arranged on the optical waveguide sheet and couples light emitted by an external light source component into the optical waveguide sheet; the turning grating is used for receiving light coupled into the grating; the coupling grating is used for receiving the light of the turning grating; the light homogenizing film layer is arranged on at least one of the turning grating and the coupling-out grating and is provided with a plurality of light homogenizing regions, and the thicknesses and/or materials of at least two light homogenizing regions in the light homogenizing regions are different, so that the light homogenizing effects of the light homogenizing regions on the light are different.

By arranging the optical waveguide sheet, the optical waveguide sheet provides arrangement positions for the coupling-in grating, the turning grating and the coupling-out grating, improves the use reliability of the coupling-in grating, the turning grating and the coupling-out grating, and is beneficial to stable transmission of light in the optical waveguide sheet. The coupling-in grating is arranged on the optical waveguide sheet, so that the coupling-in grating can couple most of light emitted by an external light source component into the optical waveguide sheet, and the coupling-in efficiency is ensured. And then make the turning grating can receive most light of coupling-in grating, so that the turning grating realizes the extended pupil transmission of light, and then transmit the amplified light to the coupling-out grating, and then the coupling-out grating couples the light out of the optical waveguide sheet, so that most of the light coupled out by the coupling-out grating can enter human eyes for imaging, so as to ensure the imaging integrity and stability of the optical waveguide sheet.

In addition, through setting up the even light zone that material and/or thickness are different, so that even light zone can realize material modulation and/or thick modulation of membrane, so that even light zone can realize carrying out grating diffraction efficiency modulation to the grating at its place, in order to adjust the diffraction efficiency in corresponding the different positions of grating, in order to avoid the partial inhomogeneous condition that the bright part is too dark to appear in the image picture, make the optical waveguide structure of this application under the prerequisite that does not increase processing cost and technology degree of difficulty, the demonstration homogeneity has been improved greatly, and the cost is saved simultaneously, production efficiency has been increased.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, 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 optical waveguide structure;

FIG. 2 shows an optical field profile of the optical waveguide structure of FIG. 1;

FIG. 3 shows a schematic diagram of an optical waveguide structure of an alternative embodiment of the present invention;

FIG. 4 is a cross-sectional view of the turning grating of FIG. 3 along a first direction;

FIG. 5 shows an optical field profile of the optical waveguide structure of FIG. 3;

FIG. 6 shows a schematic diagram of placing multiple uniform light regions of different materials on a rectangular grating;

FIG. 7 shows a schematic view of a dodging film layer disposed on a tilted grating;

FIG. 8 shows that the materials of the uniform light regions are respectively Al₂O₃And HfO₂Thickness of (d) and corresponding 1-order diffraction efficiencyA drawing;

FIG. 9 shows a schematic view of a dodging film layer disposed on a rectangular grating;

FIG. 10 is a schematic diagram of a rectangular grating with a light homogenizing film layer deposited by atomic deposition;

FIG. 11 is a schematic structural diagram of a step grating provided with a light uniformizing film layer;

fig. 12 shows a structural diagram of a blazed grating provided with a uniform light film layer.

Wherein the figures include the following reference numerals:

10. coupling in a grating; 20. turning the grating; 21. a sub-turning grating region; 30. coupling out the grating; 31. a sub-coupling light grid region; 40. a light homogenizing film layer; 50. an eye box; 60. a first direction; 70. a second direction.

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 embodiments with reference to the attached drawings.

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 invention, unless specified to the contrary, use of the terms of orientation such as "upper, lower, top, bottom" or the like, generally refer to the orientation as shown in the drawings, or to the component itself in a vertical, perpendicular, or gravitational orientation; 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.

In order to solve the problem of uneven display effect of the optical waveguide structure in the prior art, the invention mainly aims to provide an optical waveguide structure and a display device.

As shown in fig. 1 to 12, the optical waveguide structure includes an optical waveguide sheet, an incoupling grating 10, a turning grating 20, an outcoupling grating 30 and a light-equalizing film layer 40, the incoupling grating 10 is disposed on the optical waveguide sheet, and the incoupling grating 10 couples light emitted from an external light source component into the optical waveguide sheet; the turning grating 20 is used for receiving the light coupled into the grating 10; the coupling grating 30 is used for receiving the light of the turning grating 20; the number of the light uniformizing film layers 40 is one or more, and at least one of the turning grating 20 and the coupling grating 30 is provided with the light uniformizing film layer 40, the light uniformizing film layer 40 has a plurality of light uniformizing regions, and the thicknesses and/or materials of at least two light uniformizing regions in the plurality of light uniformizing regions are different, so that the light uniformizing effects of the light uniformizing regions on light are different.

By arranging the optical waveguide sheet, the optical waveguide sheet provides arrangement positions for the incoupling grating 10, the turning grating 20 and the outcoupling grating 30, thereby improving the use reliability of the incoupling grating 10, the turning grating 20 and the outcoupling grating 30 and facilitating the stable transmission of light in the optical waveguide sheet. The incoupling grating 10 is disposed on the optical waveguide sheet, so that the incoupling grating 10 can couple most of the light emitted from the external light source assembly into the optical waveguide sheet, thereby ensuring the incoupling efficiency. And further, the turning grating 20 can receive most of the light coupled into the grating 10, so that the turning grating 20 realizes the extended pupil transmission of the light, and further transmits the amplified light to the coupling grating 30, and further the coupling grating 30 couples the light out of the optical waveguide sheet, so that most of the light coupled out by the coupling grating 30 can enter human eyes for imaging, and the imaging integrity and stability of the optical waveguide sheet are ensured.

In addition, through setting up the even light zone that material and/or thickness are different, so that even light zone can realize material modulation and/or thick modulation of membrane, so that even light zone can realize carrying out grating diffraction efficiency modulation to the grating at its place, in order to adjust the diffraction efficiency in corresponding the different positions of grating, in order to avoid the partial inhomogeneous condition that the bright part is too dark to appear in the image picture, make the optical waveguide structure of this application under the prerequisite that does not increase processing cost and technology degree of difficulty, the demonstration homogeneity has been improved greatly, and the cost is saved simultaneously, production efficiency has been increased.

Note that, at least two of the plurality of leveling regions have different thicknesses; or the materials of at least two homogenizing areas in the plurality of homogenizing areas are different; or, the thickness and material of at least two of the plurality of smoothing zones are different; the setting can be carried out according to specific conditions. Of course, the light-homogenizing film layer 40 may be disposed only on the turning grating 20, only on the coupling grating 30, or both the turning grating 20 and the coupling grating 30 may be disposed with the light-homogenizing film layer 40, which may be selected according to the actual situation.

As shown in fig. 1 and 2. Fig. 1 shows a prior art optical waveguide structure, and fig. 2 shows an imaging effect diagram of the optical waveguide structure in fig. 1. Due to different angles of view, light with different wavelengths is coupled into the grating 10 and enters the optical waveguide sheet, and due to different transmission paths, the diffraction times of the light passing through the grating are different. The display effect of the optical waveguide structure in the prior art is not uniform, as shown in fig. 1, which is the layout of the conventional three-division grating. As shown in fig. 2, the light transmitted through the optical waveguide sheet has a different path, which results in a large energy when a part of the field angle within the eye box 50 is coupled out, and a part of the field angle is lost due to multiple diffraction in the optical waveguide sheet, which results in a small energy when coupled out, so that the image formed in the eye box 50 has uneven brightness.

Specifically, the turning grating 20 has a plurality of sub-turning grating regions 21, the coupling grating 30 has a plurality of sub-coupling grating regions 31, the light uniformizing film layer 40 is disposed on the turning grating 20, and the plurality of light uniformizing regions of the light uniformizing film layer 40 are in one-to-one correspondence with at least some of the sub-turning grating regions 21, that is, since the diffraction efficiencies of at least some of the sub-turning grating regions 21 of the turning grating 20 are different, so that the diffraction of some of the sub-turning grating regions 21 is not uniform, only the plurality of light uniformizing regions corresponding to one-to-one correspondence with some of the sub-turning grating regions 21 having non-uniform diffraction efficiency can be disposed on the turning grating regions 21, and since the thicknesses or materials of the plurality of light uniformizing regions are different, the modulation effects achieved by different light uniformizing regions are different, so that the diffraction efficiencies of the whole turning grating 20 are consistent. The dodging film layer 40 is disposed on the coupling-out grating 30, and the plurality of dodging regions of the dodging film layer 40 correspond to at least some of the sub-coupling-out grating regions 31 one by one. When the diffraction of a part of the coupling-out grating 30 is not uniform or the difference is large, a plurality of light homogenizing regions corresponding to each other may be arranged on only the part of the sub-coupling-out grating region 31 with non-uniform diffraction efficiency, and due to the different thicknesses or materials of the plurality of light homogenizing regions, the modulation effects achieved by different light homogenizing regions are different, so that the diffraction efficiency of the whole coupling-out grating 30 is consistent.

Certainly, a plurality of light homogenizing regions are uniformly and correspondingly arranged on the plurality of sub-turning grating regions 21 of the turning grating 20, and a plurality of light homogenizing regions are uniformly and correspondingly arranged on the plurality of sub-coupling grating regions 31 of the coupling grating 30, so that one light homogenizing film layer 40 covers the whole turning grating 20, and the other light homogenizing film layer 40 completely covers the whole coupling grating 30.

As shown in FIG. 3, the turning grating 20 is located at one side of the coupling grating 10, the coupling grating 30 is located at one side of the turning grating 20, and a connection line between the center of the coupling grating 10 and the center of the turning grating 20 is perpendicular to a connection line between the center of the coupling grating 30 and the center of the turning grating 20. The arrangement of the coupling grating 10, the turning grating 20 and the coupling grating 30 on the optical waveguide sheet is planned, the light transmission direction is planned, and the stable imaging of the optical waveguide structure is ensured. The plurality of sub-grating transition regions 21 are sequentially arranged along the first direction 60, the plurality of sub-grating coupling regions 31 are sequentially arranged along the second direction 70, and an included angle is formed between the first direction 60 and the second direction 70, and the included angle is a right angle. As shown in fig. 3, the first direction 60 is perpendicular to the extending direction of the gate lines of the incoupling grating 10, and the second direction 70 is perpendicular to the extending direction of the gate lines of the outcoupling grating 30, that is, the sub-turning grating regions 21 are sequentially arranged from left to right, and the sub-outcoupling grating regions 31 are sequentially arranged from top to bottom.

In an embodiment not shown in the figures, the angle between the first direction and the second direction may also be acute. That is, the first direction is not perpendicular to the extending direction of the gate line coupled into the light gate 10, but is at an acute angle or an obtuse angle; the second direction is not perpendicular to the extending direction of the gate lines of the outcoupling gate 30, but is at an acute angle or an obtuse angle. That is, the first direction in the present embodiment is inclined downward or upward as compared to the first direction 60 in fig. 3, and the second direction in the present embodiment is inclined leftward or rightward as compared to the second direction 70 in fig. 3.

The first direction 60 and the second direction 70 are both linear directions.

In an embodiment not shown in the drawings, another light homogenizing film layer 40 is disposed on the incoupling grating 10, the incoupling grating 10 is divided into a plurality of sub-incoupling grating regions along the first direction 60, and a plurality of light homogenizing regions of the another light homogenizing film layer 40 correspond to at least some of the sub-incoupling grating regions one to one. In practical applications, the coupling-in grating 10 may also be coated in a partitioned manner to modulate the diffraction efficiency of the coupling-in grating 10.

Specifically, when the thicknesses of the plurality of light uniformizing regions are different and the turning grating 20 and the coupling grating 30 are both provided with the light uniformizing film layer 40, the thickness of the light uniformizing region on the side of the turning grating 20 close to the coupling grating 10 is greater than the thickness of the light uniformizing region on the side of the turning grating 20 far from the coupling grating 10; the thickness of the light homogenizing zone on the side of the coupling grating 30 close to the turning grating 20 is larger than that of the light homogenizing zone on the side of the coupling grating 30 far from the turning grating 20. The modulation of the diffraction efficiency of the corresponding grating is realized through the difference of the thicknesses of the uniform light areas, so that the final imaging can achieve the purpose of uniform display.

In the embodiment shown in fig. 4, a cross-sectional view of the turning grating 20 along a first direction 60 is shown, as well as a cross-sectional view of the outcoupling grating 30 along a second direction 70. As can be seen from the figure, the thicknesses of the uniform light regions of the uniform light film layer 40 on the turning grating 20 gradually decrease along the direction away from the incoupling grating 10, and the thickness of the uniform light region on the side of the turning grating 20 away from the incoupling grating 10 is zero; the thicknesses of the uniform light areas of the uniform light film layer 40 on the coupling grating 30 are gradually reduced along the direction far away from the turning grating 20, and the thickness of the uniform light area on the side of the coupling grating 30 far away from the turning grating 20 is zero. The thickness of the light homogenizing zone required by the corresponding zone is obtained by calculation optimization of the multiple sub-turning grating zones 21 and the multiple sub-coupling grating zones 31, and the light field distribution with uniform intensity shown in fig. 5 is finally coupled out by the optical waveguide structure through modulation in a zone coating mode. In the present embodiment, the materials of the respective smoothing areas are the same, but may be different, and may be selected according to the specific situation.

In the embodiment shown in fig. 6, the grating may be a turning grating 20 or a outcoupling grating 30. In the figure, the thicknesses of a plurality of uniform light areas of the uniform light film layer 40 on the grating are the same, and the materials of the uniform light areas are different, so that the reasonable distribution of the diffraction efficiency of the corresponding grating is realized by the mode of material modulation of the uniform light areas, and the uniform display effect can also be realized.

Specifically, the turning grating 20 is a one-dimensional grating or a two-dimensional grating; the coupling grating 30 is a one-dimensional grating or a two-dimensional grating; the one-dimensional grating is one of a rectangular grating, an inclined grating, a step grating and a blazed grating, and the two-dimensional grating is one of a cylindrical grating and a pyramidal grating. Can be set according to specific conditions.

The blazed grating is a grating having a blazed characteristic, in which the groove surface is not parallel to the normal of the grating, that is, a small included angle exists between the groove surface and the normal of the grating. The sawtooth type grating is an ideal blazed grating, and the cross section of the sawtooth type grating is in a sawtooth structure for diffraction. The tilted grating is a grating in which the plane of the grating and the tangential direction of the grating form a certain inclination angle. The rectangular grating is a grating which diffracts light with a rectangular cross section.

Specifically, the refractive index of the uniform light film layer 40 is greater than or equal to 1.4 and less than or equal to 4.9. The thickness of the uniform light film layer 40 is more than or equal to 10 nanometers and less than or equal to 2 micrometers, the thickness of the uniform light film layer 40 is limited within the range from 10 nanometers to 2 micrometers, the uniform light effect is prevented from being influenced by the fact that the thickness of the uniform light film layer 40 is too thin and the manufacturing difficulty is increased, and meanwhile, the miniaturization is influenced by the fact that the thickness of the uniform light film layer 40 is too thick and the whole thickness of the optical waveguide structure is increased.

Specifically, the material of the light homogenizing zone comprises one of silicon dioxide, doped silicon dioxide, silicon nitride, silicon oxynitride, cerium dioxide, aluminum oxide, tantalum pentoxide, beryllium oxide, calcium fluoride, cerium fluoride, chromium fluoride, lanthanum fluoride, strontium fluoride, ytterbium fluoride, silicon, doped silicon, titanium dioxide, chromium dioxide, aluminum oxide, tantalum pentoxide, aluminum oxynitride, germanium, doped germanium, hafnium oxide, magnesium oxide, neodymium oxide, praseodymium oxide, scandium oxide, zinc selenide, zinc sulfide, and zirconium oxide.

It should be noted that the plurality of light uniformizing regions of the light uniformizing film layer 40 may be disposed on the corresponding grating by evaporation or atomic deposition.

In the specific embodiment shown in fig. 7, the grating may be a turning grating 20 or a coupling grating 30, the type of the grating is a tilted grating, the modulation effect is achieved by plating uniform light regions with different thicknesses on the tilted grating, the tilted grating in the figure has a left tilt angle θ 2 of 67 °, θ 1 of 57 °, a top duty ratio L/P of 47.3%, a height H of 315nm, and a period of 390nm, and the grating efficiency is found to be greatly changed under the condition of vertical incidence by arranging the uniform light film layer 40. As shown in FIG. 8, Al plating with different thicknesses was simulated₂O₃Film and HfO of different thickness₂The figure shows that the 1 st order diffraction efficiency varies significantly from high to low with increasing film thickness, and the two materials have different modulation capability for grating efficiency. Therefore, the method for plating the uniform light areas with different thicknesses can realize the modulation of the grating efficiency, and the uniform light areas with different materials and different thicknesses have different modulation effects on the grating diffraction efficiency.

As shown in fig. 7, the arrow incident perpendicularly on the optical waveguide sheet indicates the 0-order diffraction direction, and the arrow inclined to the right indicates the 1-order diffraction direction.

As shown in fig. 9, a coating modulation mode may be adopted for the conventional rectangular grating, and the uniform light film layer 40 is arranged on the basis of the rectangular grating for modulation, so that the processing cost can be greatly reduced, and the diffraction performance can be effectively improved. As shown in fig. 10, the dodging film layer 40 of the rectangular grating is disposed by atomic deposition, which results in the dodging film layer 40 forming the structure shown in fig. 10, but the grating efficiency is also well modulated with the change of the thicknesses of the dodging regions.

As shown in fig. 11, a schematic view of a light uniformizing film layer 40 disposed on a step grating is shown. Fig. 12 is a schematic view of a blazed grating with a light homogenizing film layer 40. The plurality of light homogenizing regions of the light homogenizing film layer 40 may be different in thickness or different in material.

The display device comprises a light source assembly and the above-mentioned light guide structure, the light source assembly emitting light to the light guide structure, the light guide structure coupling out light into the human eye. The optical waveguide structure has the advantages of strong modulation capability, low cost, small process difficulty and uniform display effect. Display device can use on AR head-mounted apparatus, also can use on-vehicle HUD display device. The display device realizes the modulation of the grating efficiency by a method of coating films with different thicknesses or different material films in different areas on the basis of a simple optical waveguide structure. The method does not increase the difficulty of manufacturing the grating, particularly the cost and difficulty of processing a master plate in the nano-imprinting process.

It is to be understood that the above-described embodiments are only a few, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within 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.