CN215678840U - Grating waveguide element capable of improving light-emitting uniformity - Google Patents
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Abstract
The utility model discloses a grating waveguide element capable of improving light emitting uniformity. The grating waveguide element is characterized in that an incident grating, at least one turning grating, an emergent grating and rotary gratings are arranged on the surface of an optical substrate, wherein the incident grating and the turning grating are arranged in parallel at intervals; the emergent grating is arranged on the side surface of the turning grating at intervals; the incident grating passes through the turning grating to the emergent grating to form an incident light diffraction light path; the rotary gratings are arranged on the other side of the emergent grating at intervals, so that the emergent grating is located between the turning grating and the rotary gratings; and the rotary gratings and the emergent grating form an overflow diffraction light back-reflection light path. Through a simple mode of arranging the rotary gratings on one side of the emergent grating, the light efficiency and the energy distribution uniformity of the grating waveguide element are improved.
Description
Technical Field
The utility model relates to the field of grating waveguide elements, in particular to a grating waveguide element capable of improving light-emitting uniformity.
Background
Near-eye display devices have evolved rapidly as virtual reality and augmented reality technologies have become recognized and accepted. In the near-eye display device, the grating waveguide display technology is to realize the incidence, turning and emission of light by using a diffraction grating, realize light transmission by using the total reflection principle, transmit an image of a micro display to human eyes and further see a virtual image. The grating waveguide technology has many advantages of good perspective effect, lightness, thinness, low mass production cost and the like, and is considered as a development direction of the AR near-eye display technology.
The structure of the existing grating waveguide device is shown in fig. 1, and the whole device is composed of an optical substrate and a grating positioned on the surface of the optical substrate. The optical substrate is generally a planar structure, and the material of the optical substrate may be optical materials such as optical glass, optical plastic, etc., the main optical surfaces of the optical substrate are two surfaces parallel to each other, the grating is located on one of the surfaces of the optical substrate, and there are usually three grating regions: an entrance grating 112, a turning grating 114 and an exit grating 116. The operation principle of the grating waveguide device 100 is shown in fig. 2, light 214 with image information emitted by the projection system 210 is projected onto the incident grating 112, and the incident grating 112 will diffract to generate two diffracted lights, namely +1 st order diffracted light and-1 st order diffracted light. When the diffracted light satisfies the total reflection condition of the optical substrate, i.e., the incident angle to the optical surface is larger than the critical angle of total reflection of the optical substrate, the light beam is totally reflected and nearly transmitted without loss in the optical substrate. When the-1 st order diffracted light beam is transmitted towards-y, namely towards the turning grating 114, when the beam is incident into the area of the turning grating 114, due to the diffraction effect of the turning grating 114, the beam is transmitted along the-y direction, and simultaneously, a series of diffracted lights 216 transmitted towards the exit grating 116 are generated, the diffracted lights are transmitted to the exit grating 116, after being diffracted by the exit grating 116, the emitted diffracted lights 220 enter the human eye 212 to be sensed, and the downward diffracted lights 218 no longer satisfy the total reflection condition of the optical substrate and are guided out of the optical substrate to be leaked to the surrounding environment. The diffracted light 216 is transmitted out of the exit grating 116 in the-x direction and then continues to be transmitted forward, where it can no longer be utilized, resulting in wasted energy. In addition, when the diffracted light 216 is transmitted in the-x direction in the area of the exit grating 116, the energy gradually decreases due to the diffraction effect, so that the intensity of the exiting diffracted light 220 also gradually decreases in the-x direction, resulting in uneven light energy distribution.
In view of the above, the present invention is particularly proposed.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a grating waveguide element capable of improving the uniformity of light emission, which can effectively utilize diffracted light, improve the utilization efficiency of light energy and the uniformity of light distribution, and further solve the problems of low energy utilization rate and nonuniform energy distribution of a grating waveguide device in the prior art.
The purpose of the utility model is realized by the following technical scheme:
the embodiment of the utility model provides a grating waveguide element capable of improving light-emitting uniformity, wherein an incident grating, at least one turning grating, an emergent grating and a rotary grating are respectively arranged on the surface of one side of an optical substrate; wherein the content of the first and second substances,
the incident grating and the turning grating are arranged in parallel at intervals;
the emergent grating is arranged on the side surface of the turning grating at intervals;
the incident grating passes through the turning grating to the emergent grating to form an incident light diffraction path;
the rotary grating is arranged on the other side of the emergent grating at intervals, so that the emergent grating is positioned between the rotary grating and the rotary grating, and the rotary grating and the emergent grating form an overflow diffraction light retro-reflection light path.
Compared with the prior art, the grating waveguide element capable of improving the uniformity of the light output provided by the utility model at least has the following beneficial effects:
the rotary grating is arranged on one side of the emergent grating, so that the diffracted light transmitted out of the emergent grating is diffracted back again and transmitted to the emergent grating, the diffracted light facing to the human eye direction is generated, and the energy utilization rate is improved; in addition, considering that the light energy is gradually weakened when the diffracted light beams are diffracted and conducted in the emergent grating area, the structure utilizes the diffraction effect of the rotary grating, namely the diffracted light is input again at one side of the emergent grating, and the light energy distribution uniformity is improved; compared with the existing scheme of improving the uniformity of the exit pupil by using the exit grating structure with gradually changed period and gradually changed etching depth, the structure and the manufacturing process are simpler.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a grating waveguide device provided in the prior art;
FIG. 2 is a schematic diagram of the operation of a prior art grating waveguide device;
fig. 3 is a schematic structural diagram of a grating waveguide device capable of improving uniformity of light output according to an embodiment of the present invention;
fig. 4 is a schematic diagram illustrating an operating principle of a grating waveguide device capable of improving uniformity of light output according to an embodiment of the present invention;
fig. 5 is a schematic plan view of a working principle of a grating waveguide element capable of improving uniformity of light output according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a grating waveguide device capable of improving uniformity of light output according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a grating waveguide element capable of improving uniformity of light output according to an embodiment of the present invention.
Detailed Description
The technical scheme in the embodiment of the utility model is clearly and completely described below by combining the attached drawings in the embodiment of the utility model; it is to be understood that the described embodiments are merely exemplary of the utility model, and are not intended to limit the utility model to the particular forms disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
The terms that may be used herein are first described as follows:
the term "and/or" means that either or both can be achieved, for example, X and/or Y means that both cases include "X" or "Y" as well as three cases including "X and Y".
The terms "comprising," "including," "containing," "having," or other similar terms of meaning should be construed as non-exclusive inclusions. For example: including a feature (e.g., material, component, ingredient, carrier, formulation, material, dimension, part, component, mechanism, device, process, procedure, method, reaction condition, processing condition, parameter, algorithm, signal, data, product, or article of manufacture), is to be construed as including not only the particular feature explicitly listed but also other features not explicitly listed as such which are known in the art.
The term "consisting of … …" is meant to exclude any technical feature elements not explicitly listed. If used in a claim, the term shall render the claim closed except for the inclusion of the technical features that are expressly listed except for the conventional impurities associated therewith. If the term occurs in only one clause of the claims, it is defined only to the elements explicitly recited in that clause, and elements recited in other clauses are not excluded from the overall claims.
Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "secured," etc., are to be construed broadly, as for example: can be fixedly connected, can also be detachably connected or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms herein can be understood by those of ordinary skill in the art as appropriate.
The terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," and the like are used in an orientation or positional relationship that is indicated based on the orientation or positional relationship shown in the drawings for ease of description and simplicity of description only, and are not intended to imply or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting herein.
The grating waveguide device of the present invention capable of improving uniformity of light output will be described in detail below. Details which are not described in detail in the embodiments of the utility model belong to the prior art which is known to the person skilled in the art. Those not specifically mentioned in the examples of the present invention were carried out according to the conventional conditions in the art or conditions suggested by the manufacturer. The reagents or instruments used in the examples of the present invention are not specified by manufacturers, and are all conventional products available by commercial purchase.
As shown in fig. 3, the embodiment of the present invention provides a grating waveguide device capable of improving uniformity of light output, in which an incident grating 312, at least one turning grating 314, an exit grating 316 and a turning grating 318 are respectively disposed on a surface of an optical substrate; wherein the content of the first and second substances,
the incident grating 312 and the turning grating 314 are arranged in parallel at intervals;
the exit grating 316 is arranged at the side of the turning grating 314 at intervals;
the incident grating 312 passes through the turning grating 314 to the emergent grating 316 to form an incident light diffraction path;
the turning grating 318 is disposed at an interval on the other side of the exit grating 316, so that the exit grating 316 is located between the turning grating 314 and the turning grating 318, and the turning grating 318 and the exit grating 316 form an overflow diffractive light retroreflective optical path.
In the above-mentioned grating waveguide device, the grating period of the rotating grating 318 is half of the grating period of the emergent grating 316, and the grating line groove direction of the rotating grating 318 is parallel to the grating line groove direction of the emergent grating.
In the above grating waveguide device, the length of the rotating grating 318 is not less than 80% of the width of the exit grating 316. The position of the turning grating 318 is within the width extension of the exit grating 316.
In the grating waveguide element, the rotary grating is any one of a rectangular grating, a trapezoidal grating, an inclined grating and a blazed grating.
In the grating waveguide element, the incident grating, the turning grating and the emergent grating are all any one of rectangular grating, trapezoidal grating, inclined grating and blazed grating.
In summary, in the grating waveguide element structure according to the embodiment of the present invention, the rotary grating is disposed on one side of the exit grating, so that the diffracted light transmitted out of the exit grating is diffracted back again and transmitted to the exit grating, and the diffracted light facing to the human eye direction is generated, thereby improving the energy utilization rate; in addition, considering that the light energy is gradually weakened when the diffracted light beams are diffracted and transmitted in the emergent grating area, the structure utilizes the diffraction effect of the rotary grating, namely, the diffracted light is input again at one side of the emergent grating, and the uniformity of the light energy distribution is improved. Compared with the existing scheme of improving the uniformity of the exit pupil by using the exit grating structure with gradually changed period and gradually changed etching depth, the structure and the manufacturing process are simpler.
In order to more clearly show the technical solutions and the technical effects provided by the present invention, the following detailed description will be given of a grating waveguide device method capable of improving uniformity of light output provided by the embodiments of the present invention with specific embodiments.
Example 1
As shown in fig. 3, 4 and 5, an embodiment of the present invention provides a grating waveguide device, which is composed of an optical substrate and a grating located on a surface of the optical substrate, the grating being divided into four regions: an incident grating 312, a turning grating 314, an exit grating 316, and a turning grating 318; wherein the incident grating 312 is used for guiding the virtual image beam 414 emitted from the projection system 410 into the grating waveguide component 300, as shown in fig. 4 and 5; the incident grating 312 diffracts the incident light 414 in two approximately opposite directions, with a portion of the incident light being directed toward the region of the turning grating 314, which is typically-1 st order diffracted light, diffracted by the turning grating 314 to produce a diffracted beam 416 directed toward the exit grating 316; the diffracted beam 416 is transmitted to the exit grating 316, and after being diffracted by the exit grating 316, a first exit diffracted light 420 and a first reverse diffracted light 418 are generated, the first exit diffracted light 420 enters the human eye 412 to be perceived, and the first reverse diffracted light 418 no longer satisfies the total reflection condition of the optical substrate and is guided out of the optical substrate to be leaked to the surrounding environment; the diffracted beam 416, after being transmitted out of the exit grating 316 along the-x direction, continues to be transmitted forward to the rotating grating 318, and is diffracted by the rotating grating 318 to generate a retro-reflected diffracted light 422 transmitted toward the + x direction; the retro-reflected diffracted light 422 is transmitted along the + x direction, transmitted to the exit grating 316, and then diffracted by the exit grating 316 to generate a second exit diffracted light 426 and a second backward diffracted light 424, the second exit diffracted light 426 enters the human eye 412 to be perceived, and the second backward diffracted light 424 no longer satisfies the total reflection condition of the optical substrate, is guided out of the optical substrate, and leaks to the surrounding environment.
The first exit diffracted light 420 is generated by the diffracted light beam 416 being diffracted by the exit grating 316, and the polar angle θ of the first exit diffracted light 420420And azimuth angle phi420Are respectively obtained by the following grating equation：
nwIs the refractive index of the optical substrate, nsIs the refractive index of the surrounding environment, λ is the wavelength of the incident light, dOIs the grating period, θ, of the exit grating 316416And phi416The polar and azimuthal angles of the diffracted beam 416, respectively.
Second outgoing diffracted light 426 is generated by diffracted light beam 416 by return grating 318 and outgoing grating 316; the diffracted beam 416 is diffracted by the rotating grating 318 to generate a retroreflected diffracted light 422, and the polar angle θ of the retroreflected diffracted light 422422And azimuth angle phi422Respectively, the following grating equations are obtained:
dRis the grating period of the rotating grating 318.
The retro-reflected diffracted light 422 is diffracted by the exit grating 316, and the polar angle θ of the second exit diffracted light 426426And azimuth angle phi426Respectively, the following grating equations are obtained:
the following can be obtained from the above formulae (1), (3) and (5):
from formulae (2), (4) and (6):
when d isO＝2dRWhen, equation (7) becomes:
in this case, the formula (8) and the formula (9) are obtained simultaneously, and θ426＝θ420，
Therefore, in the grating waveguide device of the present invention, when the grating period of the rotating grating 318 is half of the grating period of the exit grating 316, the directions of the first exit diffracted light 420 and the second exit diffracted light 426 will be the same, and the directions of the first exit diffracted light 420 and the second exit diffracted light 426 are the same, so that the generation of the effects of the stray light, the image ghost, and the like can be avoided, and the optical performance of the grating waveguide device of the present invention can be ensured.
In the grating waveguide element structure, the rotary grating is arranged on one side of the emergent grating, so that the diffracted light transmitted out of the emergent grating is diffracted back again and transmitted to the emergent grating, the diffracted light facing to the human eye direction is generated, and the energy utilization rate is improved. In addition, considering that the light energy is gradually weakened when the diffracted light beams are diffracted and conducted in the emergent grating area, the structure utilizes the diffraction effect of the rotary grating, namely the diffracted light is input again at one side of the emergent grating, and the light energy distribution uniformity is improved; the structure only utilizes the rotary grating arranged on one side of the emergent grating to improve the energy distribution uniformity, and compared with the existing scheme of improving the exit pupil uniformity by utilizing the emergent grating structure with gradually changed period and gradually changed etching depth, the structure and the manufacturing process are simpler.
In the grating waveguide element, the types of the gratings are not limited, and the incident grating, the turning grating, the emergent grating and the rotary grating can adopt grating structures such as a rectangular grating, a trapezoidal grating, an inclined grating, a blazed grating and the like. The grating period and grating area shape, size and size of the incident grating, the turning grating and the emergent grating can be set and optimized according to the requirement.
Further, the specific number and distribution of the incident grating, the turning grating and the exit grating can be set arbitrarily as long as the incident diffraction optical path can be formed, for example, in the grating waveguide element 600 illustrated in fig. 6, the incident grating 612 and the turning grating 614 are horizontally arranged at intervals (in fig. 6, 616 is the exit grating, and 618 is the turning grating); the grating waveguide device 700 shown in fig. 7 is a dual-turning grating waveguide device, which has two turning gratings, i.e. 714 is a first turning grating and 716 is a second turning grating, and an incident grating 712 is sandwiched therebetween (in fig. 7, 718 is an exit grating and 720 is a turning grating); as long as one side of the emergent grating which is transmitted out by the light has no other grating structure, the rotary grating can be arranged to improve the energy utilization rate and the exit pupil uniformity of the whole grating waveguide element.
Furthermore, in the grating waveguide component, the shape, size and size of the grating region of the rotary grating can be set and optimized as required, as long as the grating period of the rotary grating is half of the grating period of the emergent grating, and the direction of the grating line groove is parallel to the direction of the grating line groove of the emergent grating.
Further, the rotation grating and the exit grating may be located on the same surface or different surfaces of the optical substrate, and the rotation grating and the exit grating operate in the transmission mode or the reflection mode simultaneously, or operate in the transmission mode and the reflection mode respectively.
In summary, the grating waveguide element of the embodiment of the utility model improves the light efficiency and the energy distribution uniformity of the grating waveguide element by simply arranging the rotary grating on one side of the emergent grating.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims. The information disclosed in this background section is only for enhancement of understanding of the general background of the utility model and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Claims (6)
1. A grating waveguide component capable of improving light-emitting uniformity is characterized in that an incident grating (312), at least one turning grating (314), an emergent grating (316) and a turning grating (318) are respectively arranged on the surface of an optical substrate; wherein the content of the first and second substances,
the incident grating (312) and the turning grating (314) are arranged in parallel at intervals;
the emergent grating (316) is arranged on the side surface of the turning grating (314) at intervals;
the incident grating (312) passes through the turning grating (314) to the emergent grating (316) to form an incident light diffraction path;
the rotary grating (318) is arranged on the other side of the emergent grating (316) at intervals, so that the emergent grating (316) is positioned between the turning grating (314) and the rotary grating (318), and the rotary grating (318) and the emergent grating (316) form an overflow diffraction light retro-reflection light path.
2. The grating waveguide component capable of improving the uniformity of the outgoing light as claimed in claim 1, wherein the grating period of the turning grating (318) is half of the grating period of the outgoing grating (316), and the grating line groove direction of the turning grating (318) is parallel to the grating line groove direction of the outgoing grating.
3. A grating waveguide element capable of improving the uniformity of the outgoing light according to claim 1 or 2, wherein the length of the turning grating (318) is not less than 80% of the width of the outgoing grating (316).
4. A grating waveguide element according to claim 1 or 2, wherein the rotating grating is any one of a rectangular grating, a trapezoidal grating, an inclined grating, and a blazed grating.
5. The grating waveguide component according to claim 1 or 2, wherein the incident grating, the turning grating, and the emergent grating are each one of a rectangular grating, a trapezoidal grating, an inclined grating, and a blazed grating.
6. A grating waveguide element according to claim 1 or 2, wherein the turning grating and the exit grating are located on the same surface or different surfaces of the optical substrate;
the rotary grating is in a transmission mode or a reflection mode, and the emergent grating is in a transmission mode or a reflection mode.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115145042A (en) * | 2022-09-06 | 2022-10-04 | 北京亮亮视野科技有限公司 | Diffractive waveguide device and near-to-eye display apparatus |
| CN116381845A (en) * | 2023-06-07 | 2023-07-04 | 北京亮亮视野科技有限公司 | Coupling-in grating, diffraction grating waveguide and near-to-eye display device |
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2021
- 2021-06-24 CN CN202121413566.9U patent/CN215678840U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115145042A (en) * | 2022-09-06 | 2022-10-04 | 北京亮亮视野科技有限公司 | Diffractive waveguide device and near-to-eye display apparatus |
| CN115145042B (en) * | 2022-09-06 | 2022-11-18 | 北京亮亮视野科技有限公司 | Diffractive waveguide device and near-to-eye display apparatus |
| CN116381845A (en) * | 2023-06-07 | 2023-07-04 | 北京亮亮视野科技有限公司 | Coupling-in grating, diffraction grating waveguide and near-to-eye display device |
| CN116381845B (en) * | 2023-06-07 | 2023-09-05 | 北京亮亮视野科技有限公司 | Coupling-in grating, diffraction grating waveguide and near-to-eye display device |
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