Light guide device
By designing waveguide sheets and multi-layer grating structures in the light guide elements of AR glasses, optimizing the guidance and distribution of light, the problem of insufficient brightness and uniformity in the prior art is solved, and the effect of higher brightness and uniform pictures is achieved.
Patent Information
- Application Number
- CN202411880161.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-11-08
- Filing Date
- 2024-12-19
- Publication Date
- 2025-02-21
AI Technical Summary
While the light guide elements of existing AR glasses provide real environments and virtual images, it is difficult to improve brightness and uniformity, resulting in poor user experience.
Design a light guide device, including a waveguide sheet, a first grating region, a second grating region and a third grating region. Through the combination of a fine grating structure and a buffer layer, the incident, turning and emission of light rays are optimized to ensure the energy of light Efficient guidance and even distribution.
It realizes providing higher brightness and more uniform picture in AR glasses lenses, improving user experience.
Smart Images
Figure CN119493213A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a light guiding device. Background Art
[0002] Augmented Reality (AR) is a technology that combines the real environment with the screen display of virtual objects. With the development of various software and hardware, AR technology has made great progress and has begun to be applied in various electronic devices.
[0003] Among the various applications of AR, the technology of AR glasses is worth noting. AR glasses usually use a light-guiding element formed by a combination of a waveguide and multiple groups of grating structures as a lens. Through the diffraction of the grating, the light projected by the equipped small projector is guided through the waveguide to the user's naked eyes, so that the user can simultaneously see the real environment around him and the virtual image projected by the small projector. Summary of the invention
[0004] An object of the present invention is to provide a light guide device to solve at least one of the above problems.
[0005] According to one embodiment of the present disclosure, a light-guiding device includes a waveguide plate, a first grating region, a second grating region, and a third grating region. The waveguide plate has a first surface and a second surface opposite to each other. The first grating region is located on the first surface or the second surface and has a first grating structure. The first grating structure is configured for light to enter the waveguide plate. The second grating region is located on the first surface and has a second grating structure. The second grating structure is configured to receive light from the first grating region and deflect the light. The third grating region is located on the first surface and has a third grating structure. The third grating structure is configured to receive light from the second grating region and emit the light out of the waveguide plate. The height of the second grating structure and the height of the third grating structure are both less than one tenth of the height of the first grating structure.
[0006] In some embodiments, the height of the first grating structure is greater than 1 micron.
[0007] In some embodiments, the height of the second grating structure is in the range of 10 nm to 300 nm.
[0008] In some embodiments, the height of the third grating structure is in the range of 10 nm to 300 nm.
[0009] In some embodiments, the light guiding device further includes a buffer layer located between the first grating region and the waveguide plate.
[0010] In some embodiments, the light guiding device further includes a dielectric layer located between the buffer layer and the waveguide plate.
[0011] In some embodiments, the material of the dielectric layer is optical adhesive.
[0012] In some embodiments, the refractive index of the buffer layer is greater than or equal to the refractive index of the dielectric layer, and the refractive index of the dielectric layer is greater than or equal to the refractive index of the waveguide plate.
[0013] In some embodiments, the thickness of the buffer layer is in the range of 0.1 mm to 10 mm.
[0014] In some embodiments, the thickness of the buffer layer meets
[0015] D≥(A 0.5 -T×tanθ d ) / tanθ d
[0016] Wherein D is the thickness of the buffer layer, A is the area of the first grating region, T is the thickness of the waveguide plate, and θd is the angle of diffraction of the light when the light enters the waveguide plate through the first grating structure.
[0017] In some embodiments, an area of the third grating region is greater than or equal to an area of the second grating region.
[0018] In some embodiments, the area of the second grating region is greater than ten times the area of the first grating region.
[0019] In some embodiments, the second grating region has a plurality of sub-regions, and each sub-region has a different diffraction efficiency.
[0020] In some embodiments, the second grating structures in the same sub-region of the second grating region have the same height and width.
[0021] In some embodiments, the second grating structures in different sub-regions of the second grating region have different heights or widths.
[0022] In some embodiments, a plurality of dividing lines of the second grating region have an angle with the horizontal direction, and the angle meets
[0023] φ=tan -1 (β1 / α1)
[0024] Wherein α1=(-λsinψ+αd) / nd, β1=(λcosψ+βd) / nd, α=sinθ×cosψ, β=sinθ×sinψ, φ is the angle, λ is the wavelength of the light, θ is the viewing angle, n is the refractive index of the waveguide, ψ is the grating vector direction of the first grating region, and d is the grating period distance of the first grating region.
[0025] In some embodiments, the number of sub-regions of the second grating region is at least three.
[0026] In some embodiments, the first grating structure is a bulk grating.
[0027] In some embodiments, the second grating structure is a nano-microstructure grating.
[0028] In some embodiments, the third grating structure is a nano-microstructure grating.
[0029] In the above-mentioned light guide device, since the height of the second grating structure and the height of the third grating structure are both less than one tenth of the height of the first grating structure, the first grating structure can provide better light guide energy efficiency when light is incident. In addition, the design of the second grating area allows the projected light to have better energy distribution uniformity. Therefore, when such a light guide device is applied to the lenses of augmented reality (AR) glasses, it can provide a brighter and more uniform picture. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] When read together with the accompanying drawings, the mode of the present disclosure can be best understood from the following embodiments. Note that according to standard practice in this industry, various features are not drawn to scale. In fact, the size of various features can be arbitrarily increased or reduced for clarity of discussion.
[0031] Figure 1 FIG. 4 is a top view of a light guide device according to an embodiment of the present disclosure.
[0032] Figure 2A for Figure 1 Side view of the light guide device in FIG.
[0033] Figure 2B for Figure 1 Schematic diagram of the first grating area receiving an image of a light source.
[0034] Figure 3A for Figure 2A A local enlarged view of the second grating structure in FIG.
[0035] Figure 3B It is a partially enlarged view of the second grating structure according to another embodiment of the present disclosure.
[0036] Figure 3C for Figure 1 A local enlarged top view of the first grating area.
[0037] Figure 4 for Figure 3A or Figure 3B A partial enlargement of a single partition in .
[0038] Figure 5A for Figure 2A A local enlarged view of the area near the first grating region.
[0039] Figure 5B It is a partial enlarged view of the area near the first grating region of the light guiding device according to another embodiment of the present disclosure.
[0040] Figure 6 It is a side view of a light guide device according to another embodiment of the present disclosure.
[0041] The reference numerals are as follows:
[0042] 100, 100a, 100b: light guide device
[0043] 110: Waveguide
[0044] 112: First surface
[0045] 114: Second surface
[0046] 120, 120b: first grating area
[0047] 122: First grating structure
[0048] 130: Second grating area
[0049] 132: Second grating structure
[0050] 134: Partition
[0051] 140: Third grating area
[0052] 142: Third grating structure
[0053] 150: buffer layer
[0054] 160: Dielectric layer
[0055] 200: Light source
[0056] A: Area
[0057] B: Dividing line
[0058] D:Thickness
[0059] d: grating period distance
[0060] H1,H2,H3: Height
[0061] L: Light
[0062] T:Thickness
[0063] X: horizontal direction
[0064] φ: Angle
[0065] ψ: grating vector direction
[0066] θ: viewing angle
[0067] θ d :diffraction angle DETAILED DESCRIPTION
[0068] The following disclosure provides many different embodiments or examples for implementing the different features of the described subject matter. Specific examples of components and configurations are described below to simplify this specification. Of course, these are merely examples and are not restrictive. For example, forming a first feature on or above a second feature in the subsequent description may include an embodiment in which the first feature and the second feature are formed in direct contact, and may also include an embodiment in which additional features may be formed between the first feature and the second feature, so that the first feature and the second feature may not be in direct contact. In addition, the present disclosure may reuse reference numbers and / or reference letters in multiple examples. Such repetition is for the purpose of simplicity and clarity, and does not itself represent the relationship between the multiple embodiments and / or configurations discussed.
[0069] Spatially relative terms such as "below," "beneath," "bottom," "above," "top," and the like may be used herein for descriptive purposes to describe the relationship of one element or feature to another element or feature as illustrated in the accompanying drawings. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation illustrated in the accompanying drawings. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should likewise be interpreted accordingly.
[0070] Figure 1 FIG. 1 is a top view of a light guide device 100 according to an embodiment of the present disclosure. Figure 2A for Figure 1 A side view of the light guide device 100 in FIG. Figure 1 and Figure 2A , the light guide device 100 includes a waveguide plate 110, a first grating region 120, a second grating region 130 and a third grating region 140. The waveguide plate 110 has a first surface 112 and a second surface 114 opposite to each other. The first grating region 120 is located on the first surface 112 and has a first grating structure 122. The first grating structure 122 is configured to allow light L to enter the waveguide plate 110. The second grating region 130 is located on the first surface 112 and has a second grating structure 132. The second grating structure 132 is configured to receive the light L from the first grating region 120 and deflect the light L. The third grating region 140 is located on the first surface 112 and has a third grating structure 142. The third grating structure 142 is configured to receive the light L from the second grating region 130 and emit the light L out of the waveguide plate 110 for human eyes to see.
[0071] In the present embodiment, the second grating region 130 is shown to have five sub-regions 134, but the present invention is not limited thereto. The area of the third grating region 140 is greater than or equal to the area of the second grating region 130, and the area of the second grating region 130 is greater than ten times the area of the first grating region 120. The height H2 of the second grating structure 132 and the height H3 of the third grating structure 142 are both less than one tenth of the height H1 of the first grating structure 122. In the present embodiment, the height H2 of the second grating structure 132 and the height H3 of the third grating structure 142 are both within the range of 10 nm to 300 nm. In other embodiments, the height H2 of the second grating structure 132 and the height H3 of the third grating structure 142 are both nanometer-scale, while the height H1 of the first grating structure 122 is micrometer-scale. For example, the height H1 of the first grating structure 122 may be 2000 nm, the height H2 of the second grating structure 132 may be 10 nm to 150 nm, and the height H3 of the third grating structure 142 may be 60 nm.
[0072] Specifically, since the height H2 of the second grating structure 132 and the height H3 of the third grating structure 142 are both less than one tenth of the height H1 of the first grating structure 122 , the first grating structure 122 can provide better light guiding energy efficiency when the light L is incident.
[0073] Figure 2B for Figure 1 FIG. 1 is a schematic diagram of the first grating area 120 receiving an image from the light source 200 . The light guide device 100 receives the image light from the light source 200 through the first grating area 120 . Figure 2B Only for expressing the concept of the subsequent viewing angle θ, in fact, the heights of the grating structures of the first grating region 120 , the second grating region 130 and the third grating region 140 are as described above.
[0074] Figure 3A for Figure 2A A local enlarged view of the second grating structure 132 in FIG. Figure 3B FIG. 1 is a partial enlarged view of the second grating structure 132 according to another embodiment of the present disclosure. Figure 2A and Figure 3A In this embodiment, the second grating region 130 has a plurality of sub-regions 134, and the heights of the second grating structures 132 in different sub-regions 134 are different. Figure 2A and Figure 3B In this embodiment, the widths of the second grating structures 132 in different subareas 134 of the second grating region 130 are different. Figure 4, the height and width of the second grating structure 132 in the same sub-area 134 are the same. In this way, the second grating structures 132 in different sub-areas 134 can have different diffraction efficiencies. The sub-areas 134 of the second grating region 130 are designed so that the projected light L (see Figure 2A ) has better energy distribution uniformity. Therefore, when such a light guide device 100 is applied to the lenses of augmented reality (AR) glasses, it can provide a brighter and more uniform picture. In addition, in some embodiments, the heights of the second grating structures 132 in the same subarea 134 of the second grating area 130 are the same, such as Figure 4 shown.
[0075] Reference Figure 3A and Figure 3B , Figure 3A and Figure 3B FIG. 1 shows a partial enlargement of three partitions 134. However, in other embodiments, the partitions 134 may be other numbers. In some embodiments, the number of partitions 134 is at least three. The dividing line B of the partitions 134 has an angle φ with the horizontal direction X (see FIG. 1 ). Figure 1 ), and the angle φ meets
[0076] φ=tan -1 (β1 / α1)
[0077] Where α1=(-λsinψ+αd) / nd, β1=(λcosψ+βd) / nd, α=sinθ×cosψ, β=sinθ×sinψ, λ is the wavelength of light L, θ is the viewing angle (see Figure 2B ), n is the refractive index of the waveguide plate 110, where the grating vector direction ψ (see Figure 3C ) is the angle between the extension direction of the slits of the first grating area 120 and the horizontal direction X, and the horizontal direction X is the same as or parallel to the horizontal direction X of the angle φ, and d is the grating period distance of the first grating area 120. In this way, the energy distribution of the light L from the second grating area 130 to the third grating area 140 can be more uniform, so that the light guide device 100 can provide a more uniform brightness distribution of the projected picture.
[0078] In the present embodiment, the first grating structure 122 is a bulk grating. Thus, the design of the bulk grating can make the height H1 of the first grating structure 122 higher, for example, reaching more than 1 micron. In the present embodiment, the second grating structure 132 is a nano-microstructure grating, and can be formed by embossing. In addition, the third grating structure 142 is a nano-microstructure grating similar to the second grating structure 132. Thus, the optical properties of the second grating structure 132 and the third grating structure 142 can be finely controlled, so that the second grating region 130 can form a plurality of sub-regions 134 with different diffraction efficiencies.
[0079] By combining the first grating structure 122 using a bulk grating and the second grating structure 132 and the third grating structure 142 using a nanostructured grating, the grating coupling efficiency of the light guide device 100 can be improved. Compared with the light guide device using only the nanostructured grating, the grating coupling efficiency of the light guide device 100 in this embodiment can be improved by about 57%. Therefore, when the light guide device 100 is applied to the lenses of augmented reality (AR) glasses, it can provide a brighter and more uniform picture.
[0080] Figure 5A for Figure 2A A local enlarged view of the area near the first grating region 120 in FIG. Figure 5B FIG. 1 is a partial enlarged view of the vicinity of the first grating region 120 of the light guide device 100a according to another embodiment of the present disclosure. Figure 5A and Figure 5B , the difference between the light guide device 100a and the light guide device 100 is that the light guide device 100a further includes a buffer layer 150 and a dielectric layer 160. The buffer layer 150 of the light guide device 100a is located between the first grating region 120 and the waveguide plate 110, and the dielectric layer 160 is located between the buffer layer 150 and the waveguide plate 110. The refractive index of the buffer layer 150 of the light guide device 100a is greater than or equal to the refractive index of the dielectric layer 160, and the refractive index of the dielectric layer 160 is greater than or equal to the refractive index of the waveguide plate 110. In some embodiments, the material of the dielectric layer 160 may be optical glue to fix the buffer layer 150 on the waveguide plate 110. The buffer layer 150 of the light guide device 100a can reduce the secondary coupling effect that is easy to occur in the first grating region 120, so as to reduce the loss of energy efficiency.
[0081] In some embodiments, the thickness D of the buffer layer 150 may be in the range of 0.1 mm to 10 mm, for example 7 mm, and the thickness D of the buffer layer 150 meets
[0082] D≥(A 0.5 -T×tanθ d ) / tanθ d
[0083] Where D is the thickness of the buffer layer 150, A is the area of the first grating region 120, T is the thickness of the waveguide plate 110, and θ d is the diffraction angle of the light L when the light L enters the waveguide plate 110 via the first grating structure 122. Such a thickness D can provide the best coupling efficiency.
[0084] Figure 6 FIG. 1 is a side view of a light guide device 100b according to another embodiment of the present disclosure. As shown in the figure, the light guide device 100b includes a waveguide plate 110, a first grating region 120b, a second grating region 130 and a third grating region 140. Figure 2A The difference between the light guide device 100 and the light guide device 100b is that the first grating region 120b of the light guide device 100b is located on the second surface 114 of the waveguide plate 110, and the first grating region 120b is not provided on the first surface 112 of the waveguide plate 110 of the light guide device 100b. Such a light guide device 100b has the same advantages as the aforementioned light guide device 100, so for the design of augmented reality (AR) glasses, it is possible to choose to set the first grating region 120 on the first surface 112 of the waveguide plate 110 or to set the first grating region 120b on the second surface 114 of the waveguide plate 110.
[0085] The foregoing summarizes the features of several embodiments so that those skilled in the art can better understand the various modes of the present disclosure. Those skilled in the art will appreciate that they can readily use the present disclosure as a basis for designing or modifying other methods and structures for achieving the same purpose and / or obtaining the same advantages of the embodiments introduced herein. Those skilled in the art will also recognize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may be variously changed, substituted, and modified herein without departing from the spirit and scope of the present disclosure.
Claims
1. A light guide device, comprising: A waveguide having a first surface and a second surface opposite to each other; a first grating region, located on the first surface or the second surface and having a first grating structure, configured to allow a light to be incident on the waveguide plate; a second grating region, located on the first surface and having a second grating structure, configured to receive the light from the first grating region and deflect the light; and A third grating region is located on the first surface and has a third grating structure, configured to receive the light from the second grating region and emit the light out of the waveguide, wherein a height of the second grating structure and a height of the third grating structure are both less than one tenth of a height of the first grating structure. 2 . The light guiding device as claimed in claim 1 , wherein the height of the first grating structure is greater than 1 micrometer. 3 . The light guiding device as claimed in claim 1 , wherein the height of the second grating structure is in a range of 10 nm to 300 nm. The light guiding device as claimed in claim 1 , wherein the height of the third grating structure is within a range of 10 nm to 300 nm.
5. The light guide device according to claim 1, further comprising: A buffer layer is located between the first grating region and the waveguide plate.
6. The light guide device according to claim 5, further comprising: A dielectric layer is located between the buffer layer and the waveguide plate. 7 . The light guide device as claimed in claim 6 , wherein a material of the dielectric layer is optical adhesive. 8 . The light guiding device as claimed in claim 6 , wherein a refractive index of the buffer layer is greater than or equal to a refractive index of the dielectric layer, and a refractive index of the dielectric layer is greater than or equal to a refractive index of the waveguide plate. 9 . The light guide device as claimed in claim 5 , wherein a thickness of the buffer layer is in a range of 0.1 mm to 10 mm.
10. The light guide device as claimed in claim 9, wherein the thickness of the buffer layer meets D≥(A 0.5 -T×tanθ d ) / tanθ d Where D is the thickness of the buffer layer, A is the area of the first grating region, T is the thickness of the waveguide plate, and θ d is the diffraction angle of the light when the light enters the waveguide plate through the first grating structure. 11 . The light guiding device as claimed in claim 1 , wherein an area of the third grating region is greater than or equal to an area of the second grating region. 12 . The light guiding device as claimed in claim 11 , wherein an area of the second grating region is greater than ten times an area of the first grating region. 13 . The light guiding device as claimed in claim 1 , wherein the second grating region has a plurality of sub-regions, wherein each of the plurality of sub-regions has a different diffraction efficiency. 14 . The light-guiding device as claimed in claim 13 , wherein the second grating structures in the same one of the plurality of subareas of the second grating region have the same height and width. 15 . The light guiding device as claimed in claim 13 , wherein the second grating structures in different ones of the plurality of subareas of the second grating region have different heights or widths.
16. The light guide device as claimed in claim 13, wherein a plurality of dividing lines of the plurality of subareas of the second grating region have an angle with a horizontal direction, and the angle conforms to φ=tan -1 (β1 / α1) Wherein α1=(-λsinψ+αd) / nd, β1=(λcosψ+βd) / nd, α=sinθ×cosψ, β=sinθ×sinψ, φ is the angle, λ is the wavelength of the light, θ is a viewing angle, n is the refractive index of the waveguide, ψ is the grating vector direction of the first grating region, and d is the grating period distance of the first grating region. 17 . The light guiding device as claimed in claim 13 , wherein the number of the plurality of sub-regions of the second grating region is at least three.
18. The light guiding device as claimed in claim 1, wherein the first grating structure is a bulk grating.
19. The light guiding device as claimed in claim 1, wherein the second grating structure is a nano-microstructure grating. 20 . The light guiding device as claimed in claim 1 , wherein the third grating structure is a nano-microstructure grating.