Diffractive optical waveguide device
By forming independent left and right half areas on the optical waveguide substrate, the color and brightness unevenness and ghost image problems in the diffraction optical waveguide device are solved, and a better AR display effect is achieved.
Patent Information
- Application Number
- CN202422417848.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2034-09-30
AI Technical Summary
Light of different wavelengths in existing diffraction optical waveguide devices will be diffracted to different angles when passing through the grating, resulting in uneven color and brightness. A single-chip full-color solution will produce ghost images, affecting the AR display effect.
The independent left and right half regions are formed on the optical waveguide substrate to transmit light rays through the turning units of the left and right half regions, and superimpose them in opposite directions on the coupling unit to avoid light interference and ghost images.
Enhances the color and brightness uniformity of light, reduces stray light, and improves the performance of AR display.
Smart Images
Figure CN223155315U_ABST
Abstract
Description
Technical Field
[0001] This disclosure generally relates to the field of augmented reality display technologies. More specifically, this disclosure relates to a diffractive optical waveguide device. Background Art
[0002] The diffractive optical waveguide device solution is an important way to achieve AR (Augmented Reality) display. It guides light by using a waveguide substrate and a diffraction grating, thereby effectively projecting a virtual image into the user's field of view. At the same time, it provides advantages such as thinness, lightness, and an appearance similar to that of conventional glasses for AR near-eye display devices.
[0003] However, in a diffractive optical waveguide device, due to the diffraction effect of the grating, light of different wavelengths will be diffracted to different angles after passing through the grating, thus having different propagation steps, and ultimately resulting in the non-coincidence of the energy centers of different colored lights emerging onto the user's field of view, causing color non-uniformity. In addition, due to the obvious angular response of the diffraction efficiency of the grating at different diffraction angles, the diffraction efficiencies of lights of different wavelengths at different diffraction angles will also be different, further exacerbating the color non-uniformity and also causing non-uniformity in the brightness distribution of a single color.
[0004] Currently, the main solution to the above problems is a single-chip full-color solution, which improves the problems of color non-uniformity and uneven brightness distribution by using high-order diffraction of the grating to make lights of different wavelength bands propagate in different orders, or by using single-layer double-sided or single-layer double-K domain channel superposition. However, although the single-chip full-color solution has advantages in terms of thickness and weight, it will generate a large number of ghost images, resulting in poor display effects of AR display devices.
[0005] In view of this, there is an urgent need to provide a diffractive optical waveguide device to enhance performance. Summary of the Utility Model
[0006] To solve at least one or more of the above-mentioned technical problems, this disclosure proposes a diffractive optical waveguide device in multiple aspects.
[0007] In a first aspect, this disclosure provides a diffractive optical waveguide device, characterized by comprising:
[0008] An optical waveguide substrate;
[0009] An input coupling unit disposed on the optical waveguide substrate for coupling incident light into the optical waveguide substrate;
[0010] A left half-region turning unit and a right half-region turning unit disposed on the optical waveguide substrate for pupil expansion and light turning;
[0011] An output unit disposed on the optical waveguide substrate, configured to couple out the light turned out by the left half-region turning unit and the right half-region turning unit to the human eye;
[0012] Wherein, independent closed K domains are respectively formed in the left half-region and the right half-region on the optical waveguide substrate, configured to guide the full-field light to propagate in their respective half-regions, and to propagate and superpose towards each other on the output unit.
[0013] In some embodiments, the left half-region turning unit includes a first turning unit and a second turning unit; the right half-region turning unit includes a third turning unit and a fourth turning unit;
[0014] Wherein, the first turning unit is configured to turn the light coupled in by the coupling unit to the second turning unit, and the second turning unit is configured to expand the pupil of the light turned by the first turning unit and turn it to the output unit;
[0015] The third turning unit is configured to turn the light coupled in by the coupling unit to the fourth turning unit, and the fourth turning unit is configured to expand the pupil of the light turned by the third turning unit and turn it to the output unit.
[0016] In some embodiments, the grating vector directions of the coupling unit and the output unit are the same and the angle with the x-axis is 0 degree or 180 degrees.
[0017] In some embodiments, the longitudinal lengths of the second turning unit and the fourth turning unit are greater than the longitudinal length of the output unit.
[0018] In some embodiments, the shape of the second turning unit is that the transverse width of one end close to the first turning unit is narrower, and the transverse width of the end far from the first turning unit is wider; the shape of the fourth turning unit is that the transverse width of one end close to the third turning unit is narrower, and the transverse width of the end far from the third turning unit is wider.
[0019] In some embodiments, both the left half-region turning unit and the right half-region turning unit are of +1 order transmission.
[0020] In some embodiments, the K domain of the left half-region and the K domain of the right half-region are symmetric about the y-axis when the incident light is perpendicularly incident on the optical waveguide substrate, and approximately symmetric about the y-axis when the incident light is non-perpendicularly incident on the optical waveguide substrate.
[0021] In some embodiments, in the K domain of the left half-region, the grating vectors of the coupling unit, the first turning unit, the second turning unit, and the output unit form a closed triangle in the clockwise direction, and in the K domain of the right half-region, the grating vectors of the coupling unit, the third turning unit, the fourth turning unit, and the output unit form a closed triangle in the counterclockwise direction.
[0022] In some embodiments, the angle between the grating vector of the first turning unit and the x-axis is from 30° to 60°.
[0023] In some embodiments, the angle between the grating vector of the second turning unit and the x-axis is from -60° to -30°.
[0024] Through a diffractive optical waveguide device provided as above, independent closed K-domains are respectively formed in the left half region and the right half region on the optical waveguide substrate, for guiding full-field light to propagate in their respective half regions, and propagating and superposing in opposite directions on the coupling-out unit and then being coupled out, so that the coupled-out light can not only enhance color uniformity and brightness uniformity, but also has no stray light and ghost images generated, thereby enhancing the performance of the diffractive optical waveguide device. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become readily understood. In the drawings, several embodiments of the present disclosure are shown in an exemplary rather than restrictive manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:
[0026] Figure 1 is a schematic structural diagram of an optical waveguide device showing some embodiments of the present disclosure;
[0027] Figure 2 is a schematic diagram of the optical path transmission of an optical waveguide device showing some embodiments of the present disclosure;
[0028] Figure 3 is a schematic diagram of the full-field light transmission in the left half region on the optical waveguide substrate showing some embodiments of the present disclosure;
[0029] Figure 4 is a schematic diagram of the closed K-domains formed in the left half region and the right half region showing some embodiments of the present disclosure;
[0030] Figure 5 is a side view of a straight-tooth grating and an inclined grating showing some embodiments of the present disclosure;
[0031] Figure 6 is a schematic diagram of an exemplary optical waveguide device showing some embodiments of the present disclosure;
[0032] Figure 7 is a partial action diagram of the light wave vector and the grating wave vector in the optical waveguide device of Example 1 of the present disclosure;
[0033] Figure 8 is a partial action diagram of the light wave vector and the grating wave vector in the optical waveguide device of Example 2 of the present disclosure;
[0034] Figure 9 It is a schematic diagram of an augmented reality display device showing some embodiments of the present disclosure;
[0035] Figure 10 It is a schematic flowchart of a diffractive optical waveguide method for improving the color and brightness uniformity of a single-chip full color provided by some embodiments of the present disclosure. Detailed implementation manners
[0036] Next, the technical solutions in the embodiments of the present disclosure will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are some, but not all, of the embodiments of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present disclosure.
[0037] It should be understood that the terms "including" and "comprising" used in the specification and claims of the present disclosure indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.
[0038] It should also be understood that the terms used in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used in the specification and claims of the present disclosure, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms. It should be further understood that the term "and / or" used in the specification and claims of the present disclosure refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.
[0039] As used in this specification and the claims, the term "if" can be interpreted as "when", "once", "in response to determining", or "in response to detecting" depending on the context. Similarly, the phrase "if determined" or "if detected [the described condition or event]" can be interpreted as meaning "once determined", "in response to determining", "once detected [the described condition or event]", or "in response to detecting [the described condition or event]" depending on the context.
[0040] Next, the detailed implementation manners of the present disclosure will be described in detail in conjunction with the accompanying drawings.
[0041] See Figure 1 , Figure 1It is a schematic structural diagram of an optical waveguide device showing some embodiments of the present disclosure. In some embodiments of the present disclosure, an optical waveguide device 100 is provided. It may include: an optical waveguide substrate 101; an input coupling unit 102 disposed on the optical waveguide substrate 101 for coupling incident light into the optical waveguide substrate 101; a left half-region turning unit 103 and a right half-region turning unit 104 disposed on the optical waveguide substrate 101 for pupil expansion and turning of light; and an output coupling unit 105 disposed on the optical waveguide substrate 101 for coupling the light turned out by the left half-region turning unit 103 and the right half-region turning unit 104 to the human eye. Among them, independent closed K domains are respectively formed in the left half-region and the right half-region on the optical waveguide substrate 101 for guiding full-field light to propagate in their respective half-regions, and propagating and superimposing towards each other on the output coupling unit 105.
[0042] In some embodiments, the input coupling unit 102 and the output coupling unit 105 are disposed in the middle of the optical waveguide substrate 101, and the output coupling unit 105 is disposed above the input coupling unit 102. The left half-region turning unit 103 and the right half-region turning unit 104 are respectively disposed on the left and right sides of the optical waveguide substrate 101. The left half-region and the right half-region of the optical waveguide substrate 101 share the input coupling unit 102 and the output coupling unit 105.
[0043] In this embodiment, the respective grating units in the left half-region and the right half-region of the optical waveguide substrate 101 respectively form independent closed K domains, so that the light coupled in by the input coupling unit 102 can propagate independently in the left half-region and the right half-region without interference, and finally propagate and superimpose towards each other on the output coupling unit 105 and then be coupled out to the human eye. Among them, the light propagation in the left half-region and the right half-region is independent propagation without interference, which can avoid the generation of ghost images. The light in the left half-region and the right half-region propagates towards each other on the output coupling unit 105 and is finally coupled out after superimposing on the output coupling unit 105, which can enhance the color uniformity and brightness uniformity of the coupled-out light. Therefore, according to such a setting, the display effect can be significantly enhanced.
[0044] In some embodiments, the left half-region turning unit 103 includes a first turning unit 1031 and a second turning unit 1032. The right half-region turning unit 104 includes a third turning unit 1041 and a fourth turning unit 1042. Among them, the first turning unit 1031 is used to turn the light coupled in by the input coupling unit 102 to the second turning unit 1032, and the second turning unit 1032 is used to expand the pupil of the light turned by the first turning unit 1031 and turn it to the output coupling unit 105; the third turning unit 1041 is used to turn the light coupled in by the input coupling unit 102 to the fourth turning unit 1042, and the fourth turning unit 1042 is used to expand the pupil of the light turned by the third turning unit 1041 and turn it to the output coupling unit 105.
[0045] In some embodiments, the first turning unit 1031 is disposed on one side of the coupling-in unit 102, and the second turning unit 1032 is disposed on one side of the coupling-out unit 105. The third turning unit 1041 is disposed on the other side of the coupling-in unit 102, and the fourth turning unit 1042 is disposed on the other side of the coupling-out unit 105. According to such an arrangement, the light coupled into the waveguide through the coupling-in unit 102 can be respectively transmitted to the first turning unit 1031 and the third turning unit 1041 for propagation, and the light turned out after pupil expansion by the second turning unit 1032 and the fourth turning unit 1042 can propagate towards each other and be superimposed on the coupling-out unit 105, and finally be coupled out to the human eye.
[0046] Those skilled in the art can understand that although a diffractive optical waveguide device is shown above in which independent closed K domains are respectively formed in the left half region and the right half region on the optical waveguide substrate, for guiding the full-field light to propagate in their respective half regions and propagate towards each other and be superimposed on the coupling-out unit. However, the grating vectors, grating types, and grating shapes of each grating unit are not specifically limited in the embodiments of the present disclosure, and those skilled in the art can flexibly set them.
[0047] In some embodiments, the coupling-in unit 102, the left half-region turning unit 103, the right half-region turning unit 104, and the coupling-out unit 105 are all single-sided one-dimensional gratings. This means that each grating unit is arranged on a single surface of the optical waveguide substrate 101, and each grating unit has a one-dimensional structural feature. According to such an arrangement, not only can the thickness and weight of the optical waveguide device 100 be reduced, making the optical waveguide device 100 easy to integrate, but also the entire optical waveguide device 100 can display full-color images, thereby realizing the function of a single-chip full color.
[0048] In some embodiments, the coupling-in unit 102, the left half-region turning unit 103, the right half-region turning unit 104, and the coupling-out unit 105 are straight-tooth gratings or inclined gratings. Reference can be made to Figure 5 , Figure 5 which is a side view showing the straight-tooth grating and the inclined grating in some embodiments of the present disclosure.
[0049] In some embodiments, as Figure 1 shown, the coupling-in unit 102 is circular, the coupling-out unit 105 is rectangular, and the first turning unit 1031 and the third turning unit 1041 are rectangular.
[0050] In some embodiments, as Figure 1As shown, the shape of the second turning unit 1032 is such that the lateral width of one end close to the first turning unit 1031 is relatively narrow, and the lateral width of the end far from the first turning unit 1031 is relatively wide. The shape of the fourth turning unit 1042 is such that the lateral width of one end close to the third turning unit 1041 is relatively narrow, and the lateral width of the end far from the third turning unit 1041 is relatively wide. According to such a structure arranged to gradually widen along the light propagation direction, the scattering and mode mismatch of light during propagation can be reduced, making the light transmission smoother and more stable.
[0051] In some embodiments, the longitudinal length of the second turning unit 1032 and the fourth turning unit 1042 is greater than the longitudinal length of the coupling-out unit 105. Among them, the lateral width of the end of the second turning unit 1032 close to the first turning unit 1031 is greater than or equal to the lateral width of the first turning unit 1031. The lateral width of the end of the fourth turning unit 1042 close to the third turning unit 1041 is greater than or equal to the lateral width of the third turning unit 1041. According to such an arrangement, the second turning unit 1032 and the fourth turning unit 1042 can completely receive the light turned by the first turning unit 1031 and the third turning unit 1041, and all the light turned out by the second turning unit 1032 and the fourth turning unit 1042 can be turned to the coupling-out unit 105 and coupled out to the human eye after being superimposed in the coupling-out unit 105. To achieve the full-field light transmission in the left half and the right half, and reduce the occurrence of stray light, thereby further enhancing the display effect.
[0052] In some embodiments, as Figure 1 shown, the end of the second turning unit 1032 close to the first turning unit 1031 and the end of the fourth turning unit 1042 close to the third turning unit 1041 may include a downwardly protruding tip, and the tip may be formed by connecting the sides of two opposite inclined surfaces.
[0053] In some embodiments, the tip of the second turning unit 1032 may be in contact with the upper part of the first turning unit 1031, and the tip of the fourth turning unit 1042 may be in contact with the upper part of the third turning unit 1041. In other embodiments, the tip of the second turning unit 1032 may also have a spacing distance from the first turning unit 1031, and the tip of the fourth turning unit 1042 may also have a spacing distance from the upper part of the third turning unit 1041. The present disclosure does not make specific limitations on this embodiment.
[0054] Those skilled in the art can understand that the above shows a specific manifestation form of the grating type and grating shape of each grating unit in a diffractive optical waveguide, but the present disclosure embodiment does not make specific limitations on this, and those skilled in the art can make flexible modifications. For example, the tips at the ends of the second turning unit 1032 and the fourth turning unit 1042 can be removed.
[0055] In some embodiments, the coupling-in unit 102 performs a ±-order transmission, so that after the incident light enters the coupling-in unit 102, it is divided into two light paths, the left and the right, which are respectively transmitted to the first turning unit 1031 in the left half region and the third turning unit 1041 in the right half region, and then are separately transmitted in their respective half regions according to the closed K-region in their respective half regions.
[0056] In some embodiments, the incident light may be perpendicularly incident or non-perpendicularly incident relative to the optical waveguide substrate 101 along the optical axis of the coupling-in unit 102. The incident angle of the incident light relative to the optical waveguide substrate 101 can be represented by (a, b). Where a represents the angle between the incident light and the x-axis on the plane of the optical waveguide substrate 101, and b represents the angle between the incident light and the y-axis on the plane of the optical waveguide substrate 101. In some other embodiments, the incident angle of the incident light relative to the plane of the optical waveguide substrate 101 can be (0, 0) or (1, 9), that is, the incident light can be perpendicularly incident into the optical waveguide substrate 101 along the optical axis of the coupling-in unit 102, or the incident light can be incident into the optical waveguide substrate 101 with angles of 1 degree and 9 degrees respectively with respect to the horizontal and vertical directions of the plane of the optical waveguide substrate 101. The embodiments of the present disclosure do not make specific limitations on this.
[0057] For example, referring to Figure 2 and Figure 6 , Figure 2 is a schematic diagram of the optical path transmission of the optical waveguide device showing some embodiments of the present disclosure, Figure 6 is a schematic diagram of an exemplary optical waveguide device showing some embodiments of the present disclosure. Wherein Figure 2 the left and right light paths coupled into by the coupling-in unit 102 in are formed by the incident light perpendicularly incident into the optical waveguide substrate 101 along the optical axis of the coupling-in unit 102. The a and c light rays in the left half region and the a' and c' light rays in the right half region propagate along the x-axis direction (horizontal direction), and the b light ray in the left half region and the b' light ray in the right half region propagate along the y-axis direction (vertical direction). Figure 6 the left and right light paths coupled into by the coupling-in unit 102 in are formed by the incident light incident into the optical waveguide substrate 101 with angles of 1 degree and 9 degrees respectively with respect to the horizontal and vertical directions of the plane of the optical waveguide substrate 101 along the optical axis of the coupling-in unit 102. The a and c light rays in the left half region and the a' and c' light rays in the right half region propagate at an angle deviating from the x-axis direction, and the b light ray in the left half region and the b' light ray in the right half region propagate at an angle deviating from the y-axis direction. However, no matter at which angle the incident light enters the coupling-in unit 102, closed K-regions can be respectively formed in the left and right half regions to guide the left and right light paths to be separately transmitted in their respective half regions.
[0058] In some embodiments, the coupling-out unit 105 performs a +1-order transmission, so that the light rays refracted in the left half-region and the right half-region are coupled out to the human eye in a +1-order transmission manner after propagating towards each other and superposing in the coupling-out unit 105.
[0059] In some embodiments, both the left half-region refraction unit 103 and the right half-region refraction unit 104 perform a +1-order transmission, that is, the first refraction unit 1031, the second refraction unit 1032, the third refraction unit 1041, and the fourth refraction unit 1042 all perform a +1-order transmission. This enables the left and right light rays coupled into the waveguide through the coupling-in point 106 of the coupling-in unit 102 to be refracted towards the coupling-out unit 105, avoiding the generation of stray light.
[0060] Specifically, as Figure 2 shown, the arrowed lines in each grating unit represent light rays, and the direction indicated by the arrow represents the propagation direction of the light rays. The process of light rays propagating in the optical waveguide substrate 101 is as follows: the incident light is vertically coupled into the optical waveguide substrate 101 at the coupling-in point 106 of the coupling-in unit 102, and the incident light is divided into left and right light rays through the ±-order transmission of the coupling-in unit 102. These two light rays will be respectively transmitted to the first refraction unit 1031 in the left half-region and the third refraction unit 1041 in the right half-region for refraction. The first refraction unit 1031 refracts the light ray to the second refraction unit 1032, and the third refraction unit 1041 refracts the light ray to the fourth refraction unit 1042. Among them, the second refraction unit 1032 expands the pupil of the light ray and then refracts the light ray to the coupling-out unit 105, and the fourth refraction unit 1042 expands the pupil of the light ray and then refracts the light ray to the coupling-out unit 105. The left and right light rays propagate towards each other in the coupling-out unit 105, and finally, after superposing at the coupling-out point 107 of the coupling-out unit, they are coupled out to the human eye.
[0061] Those skilled in the art can understand that the above shows a specific manifestation form of the diffraction orders of each grating unit in a diffractive optical waveguide, but the embodiments disclosed in this disclosure do not make specific limitations on this.
[0062] See Figure 4 , Figure 4 which is a schematic diagram showing the closed K-region formed by the left half-region and the right half-region in some embodiments of this disclosure. In some embodiments of this disclosure, as Figure 4 shown, Ki is the grating vector of the grating unit. In the K-region of the left half-region, the grating vectors of the coupling-in unit 102, the first refraction unit 1031, the second refraction unit 1032, and the coupling-out unit 105 form a closed triangle in the clockwise direction. In the K-region of the right half-region, the grating vectors of the coupling-in unit 102, the third refraction unit 1041, the fourth refraction unit 1042, and the coupling-out unit 105 form a closed triangle in the counterclockwise direction.
[0063] Specifically, as Figure 4As shown in the figure, in the closed K region of the left half region, K1 is the grating vector of the coupling-in unit 102, K2 is the grating vector of the first turning unit 1031, K3 is the grating vector of the second turning unit 1032, and K4 is the grating vector of the coupling-out unit 105. In the closed K region of the right half region, k1' is the grating vector of the coupling-in unit 102, k2' is the grating vector of the third turning unit 1041, k3' is the grating vector of the fourth turning unit 1042, and k4' is the grating vector of the coupling-out unit 105. Among them, the transmission process of light in the K region is as follows: In the K region of the left half region, the incident light forms light ray a under the action of the grating vector K1 of the coupling-in unit 102 and propagates towards the first turning unit 1031. Then, under the action of the grating vector K2 of the first turning unit 1031, light ray b is formed and propagates towards the second turning unit 1032. Then, under the action of the grating vector K3 of the second turning unit 1032, light ray c is formed and propagates towards the coupling-out unit 105. Similarly, in the K region of the right half region, the incident light forms light ray a' under the action of the grating vector K1' of the coupling-in unit 102 and propagates towards the third turning unit 1041. Then, under the action of the grating vector K2' of the third turning unit 1041, light ray b' is formed and propagates towards the fourth turning unit 1042. Then, under the action of the grating vector K3' of the fourth turning unit 1042, light ray c' is formed and propagates towards the coupling-out unit 105. Finally, light ray c from the left half region and light ray c' from the right half region are superimposed at the coupling-out point 107 of the coupling-out unit 105 and then coupled out to the human eye.
[0064] In some embodiments, the incident light may be perpendicularly incident or non-perpendicularly incident relative to the optical waveguide substrate 101 along the optical axis of the coupling-in unit 102. The K regions of the left half region and the right half region are symmetric about the y-axis when the incident light is perpendicularly incident relative to the optical waveguide substrate 101, and approximately symmetric about the y-axis when the incident light is non-perpendicularly incident relative to the optical waveguide substrate 101. For example, when the incident light is perpendicularly incident into the optical waveguide substrate 101 along the optical axis of the coupling-in unit 102, two closed K regions that are symmetric about the Y-axis are formed; when the angles of the incident light with respect to the horizontal and vertical directions of the plane of the optical waveguide substrate 101 are 1 degree and 9 degrees respectively and the incident light is incident into the optical waveguide substrate 101, two closed K regions that are approximately symmetric about the Y-axis are formed.
[0065] In this embodiment, the closed K regions in the left half region and the right half region can achieve dual-channel light transmission without interference. Finally, the light rays transmitted through the two channels propagate towards each other and are superimposed in the coupling-out unit, and then coupled out to the human eye. This can not only avoid the generation of ghost images, but also enhance the color uniformity and brightness uniformity of the light coupled out to the human eye. Moreover, since the two closed K regions are symmetric or approximately symmetric about the y-axis and have opposite vector directions, the partial light rays in the left half region and the right half region that cannot be coupled out to the human eye will continue to propagate in the other half region, and finally return to their respective half regions to continue propagating, and are coupled out to the human eye through the coupling-out unit 105. According to such a setting, the occurrence of stray light can be greatly reduced, and the transmission of light in the entire field of view can be achieved.
[0066] Specifically, taking the left half region on the optical waveguide substrate 101 as an example, the transmission of light in the entire field of view of the left half region of the optical waveguide substrate 101 disclosed in this disclosure will be explained. Refer to Figure 3 , Figure 3 FIG. is a schematic diagram showing the transmission of light in the entire field of view of the left half region on the optical waveguide substrate according to some embodiments of this disclosure. As shown in Figure 3 , the dotted line with arrows in the right half region represents the partial light rays in the left half region that cannot be coupled out to the human eye. The partial light rays in the left half region that cannot be coupled out to the human eye will continue to propagate to the right half region under the action of the coupling-out unit 105, and in the right half region, they will sequentially pass through the coupling-out unit 105, the fourth turning unit 1042, the third turning unit 1041, and the coupling-in unit 102 in the clockwise direction, and finally propagate back to the left half region and continue to pass through the coupling-in unit 102, the first turning unit 1031, the second turning unit 1032, and the coupling-out unit 105 in the clockwise direction, so as to continue to be coupled out to the human eye through the coupling-out unit 105. Similarly, the partial light rays in the right half region that cannot be coupled out to the human eye will also continue to propagate back to the left half region, propagate in the counterclockwise direction in the left half region, and finally propagate back to the right half region and continue to propagate in the counterclockwise direction, and are coupled out to the human eye through the coupling-out unit 105.
[0067] In some embodiments of this disclosure, as shown in Figure 2 , the slashes in the grating unit represent grating lines. It can be understood that the arrangement direction of the grating lines in the grating unit is the grating vector direction of the grating unit. To make the K regions in the left half region and the right half region form a closed triangle that is symmetric or approximately symmetric about the Y-axis, the left half region and the right half region on the optical waveguide substrate 101 need to be symmetric about the Y-axis, and the arrangement direction of the grating lines in each grating unit in the left half region and the right half region is set according to the grating vector direction of each grating unit in the K region of their respective half regions.
[0068] In some embodiments, the grating vector directions of the coupling-in unit 102 and the coupling-out unit 105 are the same and the included angle with the x-axis is 0 degree or 180 degrees. The periods of the coupling-in unit 102 and the coupling-out unit 105 are the same.
[0069] In some embodiments, the grating vector direction of the first turning unit 1031 forms an angle of 30 to 60 degrees with the x-axis. With such a setting, it can be ensured that after the light is turned by the first turning unit 1031, the propagation direction thereof forms an angle of 85 degrees to 95 degrees with the x-axis. The grating vector direction of the second turning unit 1041 forms an angle of -60 to -30 degrees with the x-axis. With such a setting, it can be ensured that in the K domain formed in the left half region, the grating vectors of the coupling unit 102, the first turning unit 1031, the second turning unit 1032, and the decoupling unit 105 form a closed triangle in a clockwise direction.
[0070] It should be noted that the K domain in the left half region and the K domain in the right half region are symmetric about the Y-axis or approximately symmetric about the Y-axis. Therefore, the grating vectors of the third turning unit 1041 and the fourth turning unit 1042 in the right half region are symmetric about the Y-axis or approximately symmetric about the Y-axis with respect to the first turning unit 1031 and the second turning unit 1032 in the left half region.
[0071] Specifically, in some other embodiments, the grating vector direction of the third turning unit 1041 forms an angle of -60 to -30 degrees with the x-axis. With such a setting, it can be ensured that after the light is turned by the third turning unit 1041, the propagation direction thereof forms an angle of -95 degrees to -85 degrees with the x-axis. The grating vector direction of the fourth turning unit 1042 forms an angle of 30 to 60 degrees with the x-axis. With such a setting, it can be ensured that in the K domain formed in the right half region, the grating vectors of the coupling unit 102, the third turning unit 1041, the fourth turning unit 1042, and the decoupling unit 105 form a closed triangle in a counterclockwise direction.
[0072] In some embodiments, the periods of the first turning unit 1031 and the third turning unit 1041 are the same, and the periods of the second turning unit 1032 and the fourth turning unit 1042 are the same.
[0073] For the convenience of further understanding of this disclosure, two different examples are given below. These examples do not limit this disclosure.
[0074] Example 1, such as Figure 2As shown, the grating period of the first turning unit 1031 is 261.6 nm, the angle between the grating vector and the x-axis is 45°, the grating period of the second turning unit 1032 is 261.6 nm, and the angle between the grating vector and the x-axis is -45°. The grating period of the third turning unit 1041 is 261.6 nm, the angle between the grating vector and the x-axis is 135°, and the grating period of the fourth turning unit is 261.6 nm, and the angle between the grating vector and the x-axis is -135°. The periods of the coupling-in unit 102 and the coupling-out unit 105 are both 370 nm, and the angle between the grating vector and the x-axis is 0° / 180°. The incident light is perpendicularly incident into the optical waveguide substrate 101 along the optical axis of the coupling-in unit 102. According to such a setting, in the K domain of the left half region, a total of 4 grating vectors of the coupling-in unit 102, the first turning unit 1031, the second turning unit 1032, and the coupling-out unit 105 form a closed isosceles triangle in a clockwise direction. In the K domain of the right half region, a total of 4 grating vectors of the coupling-in unit 102, the third turning unit 1041, the fourth turning unit 1042, and the coupling-out unit 105 form a closed isosceles triangle in a counterclockwise direction. And the two closed isosceles triangle K domains are symmetric about the Y axis. Therefore, the a and c light rays in the left half region and the a' and c' light rays in the right half region on the optical waveguide substrate 101 will propagate along the x-axis direction (horizontal direction), and the b light rays in the left half region and the b' light rays in the right half region will propagate along the y-axis direction (vertical direction).
[0075] Further, for Example 1 of the present disclosure above, a partial action diagram of the light wave vector and the grating wave vector in the optical waveguide device is provided. Refer to Figure 7 , Figure 7 which is a partial action diagram showing the light wave vector and the grating wave vector in the optical waveguide device of Example 1 of the present disclosure. As Figure 7 shown, the diffracted light rays shown in ① and ② are stray lights calculated by the plane grating equation of the first turning unit 1031 and the second turning unit 1032, and they are all outside the outer ring of the K domain and do not exist. The diffracted light ray shown in ③ is the light ray that is transmitted from the left half region to the coupling-out unit 105 and continues to be transmitted to hit the fourth turning unit 1042 in the right half region, and the light ray after the action of the fourth turning unit 1042 (corresponding to Figure 2 the b' light ray in). The diffracted light ray shown in ④ is the light ray after the action of the third turning unit 1041 in the right half region on the diffracted light ray shown in ③ (corresponding to Figure 2 the a' light ray in). It can be seen that the diffracted light ray ④ finally transmitted from the left half region to the right half region and after the action of the right half region has the same transmission direction as the a light ray in the left half region. Therefore, the optical path forms a closed loop, greatly reducing the generation of stray light.
[0076] Example 2, as Figure 6As shown in the figure, the grating period of the first turning unit 1031 is 249.72 nm, the angle between the grating vector and the x-axis is 41.75°, the grating period of the second turning unit is 254.1 nm, and the angle between the grating vector and the x-axis is -42.65°. The grating period of the third turning unit 1041 is 254.1 nm, the angle between the grating vector and the x-axis is 137.35°, and the grating period of the fourth turning unit 1042 is 249.72 nm, the angle between the grating vector and the x-axis is -138.25°. The periods of the coupled-in unit 102 and the coupled-out unit 105 are both 340 nm, and the angles between the grating vectors and the x-axis are 0° / 180°. The incident light enters the optical waveguide substrate 101 at an angle of 1 degree and 9 degrees with respect to the horizontal and vertical directions of the plane of the optical waveguide substrate 101 along the optical axis of the coupled-in unit 102. According to such a setting, in the K domain of the left half region, four grating vectors of the coupled-in unit 102, the first turning unit 1031, the second turning unit 1032, and the coupled-out unit 105 form a closed triangle in a clockwise direction. In the K domain of the right half region, four grating vectors of the coupled-in unit 102, the third turning unit 1041, the fourth turning unit 1042, and the coupled-out unit 105 form a closed triangle in a counterclockwise direction. And the two closed triangular K domains are approximately symmetric about the Y axis. Therefore, the a and c rays in the left half region and the a' and c' rays in the right half region on the optical waveguide substrate 101 will propagate along the x-axis direction with a certain deviation angle, and the b ray in the left half region and the b' ray in the right half region will propagate along the y-axis direction with a certain deviation angle.
[0077] Further, for Example 2 of the present disclosure above, a partial action diagram of the light wave vector and the grating wave vector in the optical waveguide device is provided. Refer to Figure 8 , Figure 8 which is a partial action diagram of the light wave vector and the grating wave vector in the optical waveguide device showing Example 2 of the present disclosure. As Figure 8 shown in the figure, the diffracted rays shown as ① and ② are stray lights calculated by the plane grating equation of the first turning unit 1031 and the second turning unit 1032, and they are all outside the outer ring of the K domain and do not exist. The diffracted ray shown as ③ is the ray that is transmitted from the left half region to the coupled-out unit 105 and then continues to be transmitted to the fourth turning unit 1042 in the right half region and is the ray after the action of the fourth turning unit 1042 (corresponding to Figure 6 the b' ray in the figure). The diffracted ray shown as ④ is the ray after the action of the third turning unit 1041 in the right half region on the diffracted ray shown as ③ (corresponding to Figure 6 the a' ray in the figure). It can be seen that the diffracted ray ④ finally transmitted from the left half region to the right half region and after the action of the right half region has the same transmission direction as the a ray in the left half region. Therefore, the optical path forms a closed loop, greatly reducing the generation of stray light.
[0078] Refer to Figure 9 , Figure 9It is a schematic diagram of an augmented reality display device showing some embodiments of the present disclosure. In some embodiments of the present disclosure, an augmented reality display device 200 is provided. It includes the optical waveguide device 100 described in the above embodiments.
[0079] In some embodiments, the augmented reality display device 200 includes two lenses (201, 202) arranged side by side, and an optical waveguide device 100 is disposed inside each lens.
[0080] In some embodiments, the coupling unit 102 in the optical waveguide device 100 is close to the upper part of the lens, so that the coupling-out unit 105 is concentrated in the middle and lower parts of the lens, corresponding to the visual center of the user, which can improve the user experience.
[0081] It can be understood that the optical waveguide device 100 in some embodiments of the present disclosure forms independent closed K domains in the left half area and the right half area on the optical waveguide substrate 101 respectively, which are used to guide the full-field light to propagate in their respective half areas, and propagate and superpose in opposite directions on the coupling-out unit 105, not only enhancing the color uniformity and brightness uniformity, but also generating no stray light and ghost images, which can significantly improve the display effect of the augmented reality display device. In some other embodiments of the present disclosure, all the gratings of the optical waveguide device 100 adopt single-sided one-dimensional gratings, which reduces the thickness and weight of the optical waveguide device 100, so that the optical waveguide device 100 is easy to be integrated into the augmented reality display device, providing the augmented reality display device with advantages such as being thin, light, and having an appearance similar to that of conventional glasses.
[0082] In some embodiments, the two lenses (201, 202) arranged side by side are connected by a connecting frame, and the embodiments of the present disclosure do not make specific limitations on this.
[0083] See Figure 10 , Figure 10 It is a schematic flowchart of a diffractive optical waveguide method for improving the color and brightness uniformity of a single-chip full color provided by some embodiments of the present disclosure. This method 10 is applied to the optical waveguide device 100 described in the above embodiments. That is, this method 10 can be executed by the optical waveguide device 10 described in the above embodiments.
[0084] In some embodiments of the present disclosure, a diffractive optical waveguide method 10 for improving the color and brightness uniformity of a single-chip full color is provided, which includes steps S102, S104, and S106:
[0085] Step S102: Coupling the incident light into the optical waveguide substrate through the coupling unit and dividing it into left and right paths;
[0086] In this embodiment, the incident light may be incident at a preset angle with respect to the optical waveguide substrate plane along the optical axis of the coupling-in unit. For the specific reference, please refer to the relevant solutions disclosed in the corresponding embodiments above, which will not be elaborated here.
[0087] Step S104: Expand the pupil and turn the light in the left and right paths respectively through the left half-region turning unit and the right half-region turning unit of the optical waveguide substrate;
[0088] In this embodiment, the left half-region turning unit includes a first turning unit and a second turning unit, and the right half-region turning unit includes a third turning unit and a fourth turning unit. For the specific reference, please refer to the corresponding embodiments above, which will not be elaborated here.
[0089] Step 106: Couple out the light turned out by the left half-region turning unit and the right half-region turning unit through the coupling-out grating after transmitting and superimposing the light in opposite directions; wherein, independent closed K-domains are respectively formed in the left half-region and the right half-region on the optical waveguide substrate, which are used to guide the full-field light to propagate in their respective half-regions, and to propagate and superimpose in opposite directions on the coupling-out unit.
[0090] In some embodiments, the K-domain in the left half-region and the K-domain in the right half-region are symmetric about the y-axis when the incident light is perpendicular to the optical waveguide substrate, and approximately symmetric about the y-axis when the incident light is non-perpendicular to the optical waveguide substrate. In this embodiment, for the independent closed K-domains formed in the left half-region and the right half-region on the optical waveguide substrate, please refer to the corresponding embodiments above, which will not be elaborated here.
[0091] Although multiple embodiments of the present disclosure have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many variations, changes, and alternative ways may occur to those skilled in the art without departing from the spirit and scope of the present disclosure. It should be understood that various alternatives to the embodiments of the present disclosure described herein may be employed in practicing the present disclosure. The appended claims are intended to define the scope of protection of the present disclosure and thus cover equivalents or alternatives within the scope of these claims.
Claims
1. A diffractive optical waveguide device, characterized in that, Comprising: An optical waveguide substrate; An input coupling unit disposed on the optical waveguide substrate for coupling incident light into the optical waveguide substrate; A left half-region turning unit and a right half-region turning unit disposed on the optical waveguide substrate for pupil expansion and light turning; An output coupling unit disposed on the optical waveguide substrate for coupling the light turned out by the left half-region turning unit and the right half-region turning unit to the human eye; Wherein, independent closed K regions are respectively formed in the left half-region and the right half-region on the optical waveguide substrate for guiding the full-field light to propagate in their respective half-regions, and propagate in opposite directions and superimpose on the output coupling unit.
2. The diffractive optical waveguide device according to claim 1, wherein The left half-region turning unit includes a first turning unit and a second turning unit; the right half-region turning unit includes a third turning unit and a fourth turning unit; Wherein, the first turning unit is used for turning the light coupled in by the input coupling unit to the second turning unit, and the second turning unit is used for pupil expansion of the light turned by the first turning unit and turning it to the output coupling unit; The third turning unit is used for turning the light coupled in by the input coupling unit to the fourth turning unit, and the fourth turning unit is used for pupil expansion of the light turned by the third turning unit and turning it to the output coupling unit.
3. The diffractive optical waveguide device according to claim 1, characterized in that, The grating vector directions of the input coupling unit and the output coupling unit are the same and the angle with the x-axis is 0 degree or 180 degrees.
4. The diffractive optical waveguide device according to claim 2, wherein The longitudinal lengths of the second turning unit and the fourth turning unit are greater than the longitudinal length of the output coupling unit.
5. The diffractive optical waveguide device according to claim 2, wherein The shape of the second turning unit is: the transverse width is narrower at the end close to the first turning unit and wider at the end far from the first turning unit; the shape of the fourth turning unit is: the transverse width is narrower at the end close to the third turning unit and wider at the end far from the third turning unit.
6. The diffractive optical waveguide device according to claim 1, wherein Both the left half-region turning unit and the right half-region turning unit are of +1 order transmission.
7. The diffractive optical waveguide device according to claim 2, characterized in that, The K region in the left half-region and the K region in the right half-region are symmetric about the y-axis when the incident light is perpendicularly incident on the optical waveguide substrate, and approximately symmetric about the y-axis when the incident light is non-perpendicularly incident on the optical waveguide substrate.
8. The diffractive optical waveguide device according to claim 7, wherein, In the K region of the left half-region, the grating vectors of the input coupling unit, the first turning unit, the second turning unit and the output coupling unit form a closed triangle in the clockwise direction; in the K region of the right half-region, the grating vectors of the input coupling unit, the third turning unit, the fourth turning unit and the output coupling unit form a closed triangle in the counterclockwise direction.
9. The diffractive optical waveguide device according to claim 2, wherein The angle between the grating vector of the first turning unit and the x-axis is 30° to 60°.
10. The diffractive optical waveguide device according to claim 2, characterized in that, The angle between the grating vector of the second turning unit and the x-axis is -60° to -30°.