Optical waveguide and augmented reality display device

Abstract

The utility model provides an optical waveguide and augmented reality display equipment. The optical waveguide includes: an optical waveguide substrate; the grating layer is arranged on the surface of the optical waveguide substrate, the grating layer comprises a grating area and a blank area, and the height of the blank area is 0.7-1.3 times that of the grating area. According to the application, the smear phenomenon generated in the use process of the optical waveguide can be weakened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a light waveguide and an augmented reality display device. BACKGROUND

[0002] There is an augmented reality display technology realized by a light waveguide in the art. However, the light waveguide in the prior art has a ghosting phenomenon (as shown in Figure 1 The ghosting problem between different frames is more serious in the dynamic imaging process. There is no good method to improve this ghosting problem in the prior art. Therefore, there is an urgent need in the art for a light waveguide which can weaken or eliminate the ghosting phenomenon generated in the use process, thereby providing a higher quality display effect. SUMMARY

[0003] To this end, the present application is committed to providing a light waveguide and an augmented reality display device which can weaken the ghosting phenomenon generated in the use process.

[0004] In one aspect, the present application provides a light waveguide, comprising: a light waveguide substrate; a grating layer, the grating layer being disposed on a surface of the light waveguide substrate, the grating layer comprising a grating region and a blank region, the height of the blank region being between 0.7 times and 1.3 times the height of the grating region.

[0005] In one possible implementation of the present application, the height of the blank region varies between 0.7 times and 1.3 times the height of the grating region.

[0006] In one possible implementation of the present application, the height of the blank region varies in a continuous manner.

[0007] In one possible implementation of the present application, the height of the blank region varies in a stepwise manner. In one possible implementation of the present application, the height of the blank region at a first end adjacent to the grating region is between 1 times and 1.3 times the height of the grating region, the height of the blank region at a second end opposite to the first end is between 0.7 times and 1 times the height of the grating region, and the height of the blank region gradually increases from the second end to the first end.

[0008] In one possible implementation of the present application, the grating region comprises a first grating region and a second grating region, the first grating region has a first height, the second grating region has a second height, the first height is less than the second height and the difference between the first height and the second height is less than or equal to 30% of the second height, the blank region is disposed between the first grating region and the second grating region, and the height of the blank region is between 0.7 times the second height and 1.3 times the first height.

[0009] In a possible implementation of the present application, the grating region includes a first grating region and a second grating region, the first grating region has a first height, the second grating region has a second height, the first height is less than the second height, the blank region is arranged between the first grating region and the second grating region, the height of the blank region close to a first end of the first grating region is between 0.7 times and 1.3 times the first height, the height of the blank region close to a second end of the second grating region is between 0.7 times and 1.3 times the second height, and the height of the blank region changes between the height of the first end and the height of the second end.

[0010] In a possible implementation of the present application, the grating region includes a first grating region and a second grating region, the first grating region and the second grating region have varying heights, the blank region is arranged between the first grating region and the second grating region, one end of the blank region close to the first grating region is a first end, one end of the blank region close to the second grating region is a second end, the first grating region has a first height at an end close to the first end, the second grating region has a second height at an end close to the second end, the first height is less than the second height, and the difference between the first height and the second height is less than or equal to 30% of the second height; and the height of the blank region is between 0.7 times the second height and 1.3 times the first height.

[0011] In a possible implementation of the present application, the grating region includes a first grating region and a second grating region, the first grating region and the second grating region have varying heights, the blank region is arranged between the first grating region and the second grating region, one end of the blank region close to the first grating region is a first end, one end of the blank region close to the second grating region is a second end, the first grating region has a first height at an end close to the first end, the second grating region has a second height at an end close to the second end, and the first height is less than the second height; the height of the first end is between 0.7 times and 1.3 times the first height, the height of the second end is between 0.7 times and 1.3 times the second height, and the height of the blank region changes between the height of the first end and the height of the second end.

[0012] In another aspect, the present application provides an augmented reality display device, including the optical waveguide described above. BRIEF DESCRIPTION OF DRAWINGS

[0013] Hereinafter, a specific embodiment of the present application will be described in detail with reference to the accompanying drawings, in which:

[0014] Figure 1 The trailing phenomenon existing in a displayed image of a display device using an optical waveguide is shown;

[0015] Figure 2 A top view of an optical waveguide according to an embodiment of the present application is shown;

[0016] Figure 3 A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ; Figure 2 A side view cross-sectional view of a light guide according to an embodiment of the application is shown in FIG. 12;

[0017] Figure 4A A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ;

[0018] Figure 4B A top view showing another light guide according to an embodiment of the application is shown in FIG. 13; Figure 4A A top view showing another light guide according to an embodiment of the application is shown in FIG. 13;

[0019] Figure 4C A top view showing another light guide according to an embodiment of the application is shown in FIG. 13; Figure 4A A top view showing another light guide according to an embodiment of the application is shown in FIG. 13;

[0020] Figure 5 A side view cross-sectional view of a light guide according to an embodiment of the application is shown in FIG. 12;

[0021] Figure 6A A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ;

[0022] Figure 6B A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ; Figure 6A A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ;

[0023] Figure 7A A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ;

[0024] Figure 7B A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ; Figure 7A A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ;

[0025] Figure 8 A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ;

[0026] Figure 9A A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ;

[0027] Figure 9B A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ; Figure 9A A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ;

[0028] Figure 9C A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ; Figure 9A A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ;

[0029] Figure 10A A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ;

[0030] Figure 10B A top view showing a light guide according to an embodiment of the application is shown in FIG. 1 1 ; Figure 10AAnother structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6.

[0031] Figure 10C Another structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6. Figure 10A Another structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6.

[0032] Figure 11A Another structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6. Another structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6.

[0033] Another structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6. Figure 11B Another structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6. Figure 11A Another structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6. Another structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6.

[0034] Another structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6. Figure 12 Another structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6. Another structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6.

[0035] Another structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown in FIG. 6. Figure 13 DETAILED DESCRIPTION

[0036] In order to make the concept and ideas of the present application more clearly understood, the present application is described in detail below with specific embodiments. It should be understood that the embodiments given herein are only a part of all the embodiments that the present application can have. Those skilled in the art can make improvements, modifications, or replacements to some or all of the embodiments described below after reading the description of the present application, and these improvements, modifications, or replacements are also included in the scope of protection of the present application.

[0037] In this document, the terms "one", "a", and other similar words are not intended to mean that only one of the described things exists, but that the description is directed to only one of the described things, which can have one or more. In this document, the terms "comprise", "include", and other similar words are intended to mean logical relationships, and cannot be regarded as indicating spatial structural relationships. For example, "A includes B" is intended to mean that B logically belongs to A, and not that B is located inside A in space. In addition, the meaning of the terms "comprise", "include", and other similar words should be regarded as open, rather than closed. For example, "A includes B" is intended to mean that B belongs to A, but B does not necessarily constitute all of A, and A can also include C, D, E, and other elements.

[0038] In this document, the terms "first", "second", and other similar terms are used to differentiate one element from another, but do not imply any order, quantity, or importance. In this document, the terms "embodiment", "this embodiment", "one embodiment", "an embodiment", and "one embodiment" do not mean that the description only applies to one specific embodiment, but also means that the description can also apply to another or more embodiments. Those skilled in the art should understand that any description made for one embodiment in this document can be replaced, combined, or otherwise combined with the description of another or more embodiments, and the new embodiments generated by the replacement, combination, or other combination are within the scope of protection of the present application.

[0039] In various embodiments of the present application, an optical waveguide can refer to a structure capable of confining light inside and guiding light to propagate along a specific path. The working principle of the optical waveguide is based on the total reflection of light. When light enters the optical waveguide at a certain angle, due to the difference in refractive index between the optical waveguide and the surrounding medium, total reflection of light occurs at the boundary of the optical waveguide, so that the light is confined inside the optical waveguide and propagates.

[0040] In various embodiments of the present application, an augmented reality display device can refer to a device that can combine virtual digital information with real scenes and present the fused content to users. It perceives the environment through cameras, gyroscopes, and other sensors, and displays using optical see-through or video see-through. When working, it matches virtual and real information according to sensor data. This device is widely used and can allow users to see virtual elements in real scenes and enhance their perception of the world.

[0041] As a technology that combines virtual information with the real world, the near-eye display system of augmented reality (AR) usually includes a miniature projector and an optical display screen, and the optical waveguide is a realization path of the optical display screen. At present, the optical waveguide scheme mainly includes geometric optical waveguide and diffractive optical waveguide. The essence of the diffractive optical waveguide is to use the diffraction characteristics of the grating to couple the incident light beam into the waveguide. When the light propagates in the waveguide, it will pass through the grating area and the blank area in turn. The interface between the two areas forms a step due to the height difference, which causes abnormal scattering and diffraction, and then causes the ghosting phenomenon. In the dynamic imaging process, the ghosting problem between different frames will be more obvious.

[0042] In some embodiments of the present application, multiple designs are provided for different situations, the height of the blank area is set to be in the range of 0.7hg~1.3hg (hg represents the height of the grating area) or a gradual height is set in the range, and the size of the blank area is determined by the adjacent two grating areas, which can effectively reduce the generation of ghosting and improve the imaging quality of the diffractive optical waveguide.

[0043] In some embodiments of the present application, the height at the junction of the grating region and the blank region without grating is set to be in the range of 0.7hg~1.3hg or a gradual height is set in the range. In this way, the ghosting phenomenon of the diffractive optical waveguide can be effectively weakened or eliminated, and the imaging quality is improved.

[0044] In some embodiments of the present application, the size of the blank region at the junction is determined by the size of the adjacent grating region, so as to avoid introducing additional steps leading to diffraction and scattering.

[0045] In some embodiments of the present application, a variety of applicable designs are provided, so that the design results have universality. Such a design method can be implemented under a variety of partition designs and a variety of grating structures, so that the design method has universality.

[0046] Figure 2 A top view of an optical waveguide according to an embodiment of the present application is shown.

[0047] As shown in Figure 2 , the optical waveguide includes an optical waveguide substrate 210 and a grating layer disposed on the surface of the optical waveguide substrate 210. The grating layer includes a grating region and a blank region 224. The grating is disposed in the grating region, and no grating is disposed in the blank region. In Figure 2 , the grating region includes a coupling-in area 221, a turning area 222, and a coupling-out area 223. The coupling-in area 221 is used to couple the image light emitted by the external light machine into the waveguide substrate, which is the entrance of the image information into the optical waveguide. The turning area 222 is used to expand the pupil and divert the transmission of the image light emitted by the coupling-in area, and guide the light to propagate in the waveguide substrate according to a predetermined path to the coupling-out area. The coupling-out area 223 is used to couple out the image light conducted in the waveguide substrate, so that the light can enter the human eye and thus be observed by the human eye as a virtual image.

[0048] Specifically, when designing a surface relief grating diffractive optical waveguide, a three-partition or two-partition design is usually used to achieve two-dimensional pupil expansion, Figure 2 A layout design of a three-partition of a diffractive optical waveguide is shown.

[0049] Figure 3 A side view cross-sectional view of an optical waveguide according to Figure 2 an embodiment of the present application is shown.

[0050] As shown in Figure 3As shown, the optical waveguide includes an optical waveguide substrate 310 and a grating layer 320. The gratings in the grating layer 320 include an in-coupling grating 321, a turning grating 322, and an out-coupling grating 323. The in-coupling grating 321 functions to couple light into the optical waveguide. The turning grating 322 functions to turn the coupled-in light. The out-coupling grating 323 functions to couple the turned light out of the optical waveguide.

[0051] It should be noted that, for ease of representation and simplicity, Figure 3 The in-coupling grating 321, the turning grating 322, and the out-coupling grating 323 are shown as being arranged in a transverse manner with equal spacing. However, according to Figure 2 It can be known that the three grating regions are arranged in a right angle manner in a top view, and their side view cross-sectional view can not be arranged in a transverse manner with equal spacing as Figure 3 shown.

[0052] In particular, in design and optimization, the optical waveguide substrate and the grating structure on the optical waveguide substrate are generally considered. The tooth shape of the grating is not unique. In the present embodiment, the gratings in the in-coupling region, the turning region, and the out-coupling region are all rectangular gratings with equal heights. It should be known by those skilled in the art that other tooth shapes and different heights can also be selected for combination design.

[0053] Figures 4A-4C A top view of three optical waveguides according to an embodiment of the present application is shown.

[0054] As Figures 4A-4C shown, the optical waveguide includes an optical waveguide substrate 410 and a grating layer. The grating layer includes a grating region and a blank region 420. The grating region includes an in-coupling region 421, a turning region 422, and an out-coupling region 423.

[0055] Figure 4A A three-part region design is shown, in which there is a blank region 431 between the in-coupling region 421 and the turning region 422, and there is also a blank region 432 between the turning region 422 and the out-coupling region 423.

[0056] Figure 4B A three-part region design is shown, in which there is no blank region between the in-coupling region 421 and the turning region 422, but there is a blank region 432 between the turning region 422 and the out-coupling region 423.

[0057] Figure 4C A two-part region design is shown, in which the grating region does not include a turning region, and there is only a blank region 433 between the in-coupling region 421 and the out-coupling region 423.

[0058] Specifically, to reduce or eliminate the trailing effect of diffracted waveguides, the boundary between the grating region and the blank region needs to be considered during the design process. Since only the propagation process of light is considered, only the blank regions between each grating section need to be analyzed. This can be achieved using methods such as... Figures 4A-4C The diagram illustrates a three-zone or two-zone design. The blank area 420 includes: a blank area 431 between the coupling-in zone 421 and the transition zone 422 in the third zone, the size of which is determined by the dimensions of the coupling-in zone 421 and the transition zone 422; a blank area 432 between the transition zone 422 and the coupling-out zone 423 in the third zone, the length of which is the same as the length of the corresponding grating zone; and a blank area 433 between the coupling-in zone 421 and the coupling-out zone 423 in the second zone, the size of which is determined by the dimensions of the coupling-in zone 421 and the coupling-out zone 423. In some cases, because the grating tooth shape and height are consistent across the three zones, it is sufficient to discuss the scattering and diffraction at a specific edge region.

[0059] Figure 5 A side cross-sectional view of an optical waveguide according to an embodiment of this application is shown.

[0060] like Figure 5 As shown, the optical waveguide includes an optical waveguide substrate 510 and a grating layer 520. The grating layer 520 includes a grating region and a blanking region. The grating region includes an input grating 521, a transition grating 522, and an output grating 523. The blanking region includes a blanking region 524 between the input grating 521 and the transition grating 522, and a blanking region 525 between the transition grating 522 and the output grating 523.

[0061] Specifically, for diffractive waveguide samples fabricated using nanoimprint technology, the waveguide substrate 510 not only contains the designed grating structure but also residual adhesive. This is because during the nanoimprint sample fabrication process, a layer of adhesive is first spin-coated onto the waveguide substrate 510, and then the grating structure on the sub-plate is imprinted onto the waveguide substrate 510, forming the designed grating tooth shape in the adhesive layer. For the blank areas, the adhesive does not disappear but remains on the waveguide substrate 510. At the boundary between the blank areas formed by the residual adhesive and the grating areas, a step with a certain height difference is formed. Figure 5 As shown in the dashed box, the presence of this step causes additional scattering and diffraction of light during propagation, resulting in motion blur when the diffracted waveguide is displayed, thus affecting the image quality.

[0062] Figure 6A and Figure 6B A schematic diagram showing the scattering and diffraction of an optical waveguide according to an embodiment of this application is provided.

[0063] like Figure 6AAs shown, the optical waveguide includes an optical waveguide substrate and a grating layer. The grating layer includes a grating region and a blank region, where the height of the blank region is h and the height of the grating region is hg, and h is less than hg.

[0064] Specifically, Figure 6A As shown, the height of the blank region is lower than the height of the grating region. When the incident light ray I is transmitted inside the waveguide, diffraction occurs to produce the R0 order and the R-1 order, where the R-1 order is on the left side of the R0 order. In order to ensure that the light ray can be totally reflected inside the waveguide, the incident angle is set to be greater than the total reflection angle, for example, the incident angle is set to be 40°.

[0065] Figure 6B As shown, the scattering and diffraction results at the boundary between the blank region and the grating region are analyzed. The horizontal axis "angle" represents the scattering and diffraction angle (the angle corresponds to the diffraction angle), and the vertical axis log(|E|2) represents the scattering and diffraction intensity. At this time, the scattering and diffraction intensity of the R0 order is higher than that of the R-1 order, and the scattering and diffraction rules of the R0 order and the R-1 order are the same, and the bandwidth of the scattering and diffraction peak of the R0 order and the R-1 order is wider on the right side than on the left side, which will cause the right side to appear trailing in the actual imaging of the optical waveguide, Figure 1 The arrow in the middle indicates the direction in which the trailing appears.

[0066] Figure 7A And Figure 7B As shown, the scattering and diffraction of the optical waveguide according to an embodiment of the present application are shown.

[0067] As Figure 7A shown, the optical waveguide includes an optical waveguide substrate and a grating layer. The grating layer includes a grating region and a blank region, where the height of the blank region is h and the height of the grating region is hg, and h is greater than hg.

[0068] Specifically, Figure 7A As shown, the height of the blank region is higher than the height of the grating region. As Figure 7B shown, the scattering and diffraction rules of the R0 order and the R-1 order are the same, and the bandwidth of the scattering and diffraction peak of the R0 order and the R-1 order is wider on the right side than on the left side, which will cause the right side to appear trailing in the actual imaging of the optical waveguide. Since the scattering and diffraction intensity of the R0 order in the present embodiment is obviously higher than that of the R-1 order, the trailing at this time is mainly contributed by the R0 order, and therefore the scattering and diffraction of the R0 order is mainly concerned.

[0069] Figure 8 The scattering and diffraction spectrum of the R0 order of the optical waveguide according to an embodiment of the present application.

[0070] As Figure 8The diagram shows the R0 diffraction order scattering diffraction spectrum as a function of the blank area height, specifically the R0 order scattering diffraction spectrum as the step height of the blank area changes. The grating height is set to 140 nm (this height is not fixed and can be adjusted according to the actual design). The vertical axis "thickness" represents the height of the blank area, varying from 0 nm to 200 nm. The dashed line corresponds to the height of the blank area where the scattering diffraction bandwidth is narrowest, i.e., the trailing effect is weakest, and hg represents the grating height. Within this height range of h to hg, the corresponding scattering diffraction bandwidths are all relatively small, and the trailing effect is weaker than at other heights. Therefore, when the grating height is set to hg, the blank area height can be set to within the range of 0.7hg to hg, at which point the trailing effect of the diffracted waveguide is weakest. To meet the design requirements of all structures, this height range can be extended to ±30% of hg, i.e., 0.7hg to 1.3hg.

[0071] Figures 9A-9C A schematic diagram of an optical waveguide according to an embodiment of this application is shown.

[0072] Figure 9A Show the corresponding height of the steps in the blank area Figure 8 A schematic diagram of the structure when h is the value in the middle. (Example) Figure 9A As shown, the optical waveguide includes an optical waveguide substrate and a grating layer. The grating layer is disposed on the surface of the optical waveguide substrate and includes a grating region and a blank region. The height h of the blank region is between 0.7 and 1.3 times the height hg of the grating region. Through extensive research and practice, the inventors of this application have discovered that the motion blur problem in optical waveguides is caused by the height difference at the boundary between the grating region and the blank region. To address this issue, this application limits the height difference between the grating region and the blank region to a certain range. Specifically, this application specifies that the height of the blank region is 0.7-1.3 times that of the grating region. This greatly alleviates the motion blur problem caused by the height difference at the boundary between the grating region and the blank region, thereby providing a better display effect and user experience.

[0073] Specifically, Figure 9A This is a structural diagram showing the blank area with a height h set to the range of 0.7hg to 1.3hg. The height h of the blank area remains constant, meaning the top surface of the blank area is horizontal.

[0074] In this embodiment, the preparation (or height adjustment) of the blank area can be carried out in the following ways. When the grating is manufactured using nanoimprinting, a material with a refractive index similar to that of the grating is filled on the residual adhesive layer in the blank area; or, when imprinting the master / daughter plate, the shape of the blank area is taken into account and designed to the corresponding master / daughter plate size. When the grating is manufactured using an etching process, the grating area is covered, and a material with a refractive index similar to that of the blank area is deposited only for filling.

[0075] Figure 9B The structure schematic diagram of the blank area step setting as a ladder gradual height is shown. As shown in the figure, the height h of the blank area varies between 0.7 times and 1.3 times of the height hg of the grating area. By making the height of the blank area vary within the specified height range, the height difference at the junction of the blank area and other areas (such as the grating area) can be reduced, the amount of height mutation at the junction can be reduced, and the blank area can be connected to other areas in a more smooth manner, which is beneficial to further weakening the ghosting phenomenon caused by the height difference. Figure 9B

[0076] For example, the height h of the blank area can vary in a ladder manner. By adopting the ladder manner of variation, the convenience of processing can be improved and the manufacturing cost can be reduced while weakening the ghosting phenomenon.

[0077] Specifically, as shown in the figure, the height of the blank area at the edge can vary within a range, so the height of the area can also be set to a ladder gradual height, and the lowest gradual height is 0.7hg, and the highest gradual height is hg or 1.3hg. Figure 9B

[0078] Figure 9C The structure schematic diagram of the blank area step setting as a smooth gradual height is shown. As shown in the figure, the height h of the blank area varies in a continuous manner. By adopting the continuous manner of variation, the height variation of the blank area can be made more smooth, which is beneficial to further weakening the ghosting phenomenon caused by the height difference. Figure 9C

[0079] At this time, the height of the blank area at the first end (the right end in the figure) close to the grating area is between 1 times and 1.3 times of the height hg of the grating area, the height of the blank area at the second end (the left end in the figure) opposite to the first end is between 0.7 times and 1 times of the height hg of the grating area, and the height h of the blank area gradually increases from the second end to the first end. By making the blank area gradually increase from the end far away from the grating area to the end close to the grating area, and making the height of the end close to the grating area be 1-1.3 times of the height of the grating area, the blank area can have a more smooth height variation manner, and have a height range at the junction with the grating area that can more weaken the ghosting phenomenon, thereby being beneficial to improving the display effect.

[0080] Specifically, as shown in the figure, the height of the blank area at the junction can be set to a smooth gradual height. Figure 9C Figures 9A-9C The design of the blank area can effectively improve the ghosting of the optical waveguide and improve the imaging quality.

[0081] Figures 10A-10C The structure schematic diagram of the optical waveguide according to an embodiment of the present application is shown.​​​​

[0082] When the heights of the respective partitions are not consistent, there are two cases discussed. One case is that the height difference between the first height hgl of the first grating region and the second height hg2 of the second grating region is less than or equal to 30% of the larger one of the first and second heights, i.e. dh≤30%*max(hgl, hg2). Figures 10A-10C The case of grating height difference dh≤30%*max(hgl, hg2) is shown.

[0083] As shown in FIG. 6, the grating region includes a first grating region having a first height hgl and a second grating region having a second height hg2, the first height hgl is less than the second height hg2, and the difference between the first height hgl and the second height hg2 is less than or equal to 30% of the first height hgl. A blank region is arranged between the first grating region and the second grating region. At this time, the height of the blank region can remain unchanged (horizontal at the top), and the height of the blank region is between 0.7 times the second height hg2 and 1.3 times the first height hgl. When the blank region is arranged between two grating regions having different heights, if the height difference between the two grating regions is less than 30% of the higher height, the blank region can be between 1.3 times the first height (lower) and 0.7 times the second height (higher). In this way, the height difference of the blank region at the junction with the first grating region does not exceed 30% of the first height, and the height difference at the junction with the second grating region does not exceed 30% of the second height, so that it can be ensured that there is no more serious smearing phenomenon at both ends of the blank region.

[0084] Specifically, Figure 10A A structural schematic diagram is shown when the blank region is arranged to be level with the lower grating region (i.e. the first grating region) (h=hgl). As shown in FIG. 7, the height of the blank region can be based on the height of the lower one of the first grating region and the second grating region, and the height of the blank region is kept consistent with the height hgl of the first grating region. Figure 10A

[0085] As shown in FIG. 8, the grating region includes a first grating region having a first height hgl and a second grating region having a second height hg2, the first height hgl is less than the second height hg2, and a blank region is arranged between the first grating region and the second grating region. The height of the blank region close to the first end of the first grating region is between 0.7 times and 1.3 times the first height hgl, the height of the blank region close to the second end of the second grating region is between 0.7 times and 1.3 times the second height hg2, and the height of the blank region changes between the height of the first end and the height of the second end. Figure 10B As shown in FIG. 8, the grating region includes a first grating region having a first height hgl and a second grating region having a second height hg2, the first height hgl is less than the second height hg2, and a blank region is arranged between the first grating region and the second grating region. The height of the blank region close to the first end of the first grating region is between 0.7 times and 1.3 times the first height hgl, the height of the blank region close to the second end of the second grating region is between 0.7 times and 1.3 times the second height hg2, and the height of the blank region changes between the height of the first end and the height of the second end.​​

[0086] Specifically, Figure 10B A structure schematic diagram in which the blank area is set to a stepped gradient height is shown. As Figure 10B indicated, the blank area can be set to a stepped gradient height. The number of steps in the gradient is not specifically required.

[0087] As Figure 10C indicated, a structure schematic diagram in which the blank area is set to a smooth gradient height is shown. Figure 10C In some embodiments, the blank area can be set to a smooth gradient height, and the gradient range is 130% of the larger of the first and second heights to 70% of the smaller of the first and second heights, i.e., from 130%*max(hg1, hg2) to 70%*min(hg1, hg2).

[0088] Figure 11A And Figure 11B A structure schematic diagram of an optical waveguide according to an embodiment of the present application is shown.

[0089] When the heights of the respective sub-gratings are inconsistent, there are two cases to be discussed. In addition to Figures 10A-10C the case shown, another case is that the height difference between the first height hg1 of the first grating area and the second height hg2 of the second grating area is greater than or equal to 30% of the larger of the first and second heights, i.e., the height difference dh≥30%*max(hg1, hg2). Figure 11A And Figure 11B A case analysis of the grating height difference dh≥30%*max(hg1, hg2) is shown.

[0090] As Figure 11AAs shown, the grating region includes a first grating region and a second grating region. The first grating region has a first height hg1, and the second grating region has a second height hg2. The first height hg1 is less than the second height hg2. A blank region is disposed between the first grating region and the second grating region. The height of the blank region at the first end adjacent to the first grating region is between 0.7 and 1.3 times the first height hg1, and the height of the blank region at the second end adjacent to the second grating region is between 0.7 and 1.3 times the second height hg2. The height of the blank region varies between the height at the first end and the height at the second end. When a blank area is placed between two grating areas at different heights, if the height difference between the two grating areas is greater than 30% of the higher height, the height of the blank area can be varied. It can be stipulated that the height difference between each end of the blank area and the first and second grating areas does not exceed 30%, that is, the height of the first end is 0.7-1.3 times the first height, and the height of the second end is 0.7-1.3 times the second height. This ensures that even if the height difference between the two grating areas is large, there will be no severe ghosting at the junction of the blank area and the two grating areas.

[0091] Specifically, Figure 11A The diagram illustrates a structure where a blank area is set to a stepped, gradually changing height. The blank area can be set to a gradually changing height, ranging from 1.3hg2 to 0.7hg1, with a gradient number ≥ 1. Figure 11A The step height is shown as a gradual change.

[0092] like Figure 11B As shown, this diagram illustrates a structure where a blank area is set with a smoothly gradient height. The blank area can be set with a gradient height, ranging from 1.3hg2 to 0.7hg1, as... Figure 11B The height gradient shown is smooth.

[0093] It should be understood that Figure 11A -B and Figure 10A The difference with -C is that, in Figure 11A In the -B case, the height difference between the first and second grating regions on either side of the blank area is significant, exceeding 30% of the height of the higher grating region. At this point, if the height of the blank area is set to remain constant, i.e., as... Figure 10A Setting the top of the blank area to horizontal would potentially result in a height difference between the blank area and the first or second grating area at the left or right end exceeding 30% of the height of the corresponding grating area. Therefore, in Figure 11A In the case of -B, it is best to set the height of the blank area to be variable, such as step gradient or smooth gradient, and the height of both ends of the blank area should be specified to be between 0.7 and 1.3 times that of the adjacent raster area. This will ensure that the height difference of the blank area at either end will not exceed 30% of the height of the corresponding raster area.

[0094] Figure 12 A structural schematic diagram of an optical waveguide according to an embodiment of the present application is shown.

[0095] As shown in Figure 12 , it shows the case that each grating partition exists height modulation. The optical waveguide includes an optical waveguide substrate 1210 and a grating layer 1220. The grating layer 1220 includes a first grating region 1221, a second grating region 1222 and a blank region 1223. When the height of each grating partition is inconsistent, the height of the blank region 1223 is determined by the first grating region 1221 and the second grating region 1222 closest to the junction.

[0096] As shown in Figure 12 , the grating region includes the first grating region 1221 and the second grating region 1222, the first grating region 1221 and the second grating region 1222 have varying heights, the blank region 1223 is arranged between the first grating region 1221 and the second grating region 1222, the end of the blank region 1223 close to the first grating region 1221 is the first end, the end of the blank region 1223 close to the second grating region 1222 is the second end, the first grating region 1221 has a first height hg1 at the end close to the first end, the second grating region 1222 has a second height hg2 at the end close to the second end, the first height hg1 is less than the second height hg2.

[0097] At this point, if the difference between the first height hg1 and the second height hg2 is less than or equal to 30% of the second height hg2, and the height of the blank area 1223 remains unchanged, then the height of the blank area 1223 is between 0.7 times the second height hg2 and 1.3 times the first height hg1. If the heights of the first and second grating areas are variable, then the height design of the blank area only needs to consider the heights of the grating areas immediately adjacent to the ends of the blank area. If the height difference between the ends of the first and second grating areas immediately adjacent to the blank area does not exceed 30%, then the height of the blank area can be specified to be between 0.7 times the second height and 1.3 times the first height, thereby ensuring that the height difference between the blank area and the boundary of the first or second grating area does not exceed 30%, thus reducing the ghosting phenomenon caused by the height difference. Alternatively, if the height of the blank area varies between the height of the first end and the height of the second end, then regardless of whether the difference between the first height hg1 and the second height hg2 is greater than or less than 30% of the second height hg2, the height of the first end should be between 0.7 and 1.3 times the first height hg1, and the height of the second end should be between 0.7 and 1.3 times the second height hg2. If the heights of the first and second grating regions vary, only the heights of their ends immediately adjacent to the blank area need to be considered. If the height of the blank area varies in this case, then it is only necessary to ensure that the height difference between the first and second ends of the blank area and the height of the end of the grating region immediately adjacent to the blank area does not exceed 30%, that is, the height of the first end should be 0.7-1.3 times the first height, and the height of the second end should be 0.7-1.3 times the second height. This ensures that no severe ghosting occurs at the boundary between the blank area and the two grating regions.

[0098] Figure 13 A schematic diagram of an optical waveguide according to an embodiment of this application is shown.

[0099] exist Figure 13 The diagram shows the filling between different raster zones. Specifically, Figure 13 A schematic diagram of the structure of a diffractive waveguide is shown. The waveguide includes a waveguide substrate 1310, a grating layer 1320, and a cover plate 1330 (or a second waveguide layer), with a dielectric 1340 filling the space between the grating layer 1320 and the cover plate 1330. The grating layer 1320 includes a first grating region 1321, a second grating region 1322, and a blank region 1323.

[0100] Figure 13 In the middle, the height of the blank area and Figures 9A-12 The height variation pattern of the blank area in the illustrated embodiment is consistent.

[0101] The concepts, principles and ideas of the present application are described in detail above in conjunction with the specific embodiments (including examples and instances). Those skilled in the art should understand that the embodiments of the present application are not only the above-mentioned forms, and after reading the present application file, those skilled in the art can make any possible improvements, replacements and equivalents to the steps, methods, devices and components in the above-mentioned embodiments, which should be considered to fall within the scope of the present application. The protection scope of the present application is only subject to the claims.

Claims

1. An optical waveguide, characterized by, Comprising: an optical waveguide substrate (310); a grating layer (320) disposed on a surface of the optical waveguide substrate (310), the grating layer (320) comprising a grating region and a blank region (224), a height of the blank region (224) being between 0.7 times and 1.3 times a height of the grating region.

2. The optical waveguide of claim 1, wherein, The height of the blank region (224) varies between 0.7 times and 1.3 times the height of the grating region.

3. The optical waveguide of claim 2, wherein, The height of the blank region (224) varies in a continuous manner.

4. The optical waveguide of claim 2, wherein, The height of the blank region (224) varies in a stepped manner.

5. The optical waveguide of claim 1, wherein, The height of the blank region (224) is between 1 times and 1.3 times the height of the grating region at a first end proximate the grating region, the height of the blank region (224) is between 0.7 times and 1 times the height of the grating region at a second end opposite the first end, the height of the blank region (224) gradually increases from the second end to the first end.

6. The optical waveguide of claim 1, wherein, The grating region comprises a first grating region (1221) having a first height (hg1) and a second grating region (1222) having a second height (hg2), the first height (hg1) being less than the second height (hg2) and a difference between the first height (hg1) and the second height (hg2) being less than or equal to 30% of the second height (hg2), the blank region (224) being disposed between the first grating region (1221) and the second grating region (1222), the height of the blank region (224) being between 0.7 times the second height (hg2) and 1.3 times the first height (hg1).

7. The optical waveguide of claim 1, wherein, The grating region comprises a first grating region (1221) having a first height (hg1) and a second grating region (1222) having a second height (hg2), the first height (hg1) being less than the second height (hg2), the blank region (224) being disposed between the first grating region (1221) and the second grating region (1222), the height of the blank region (224) being between 0.7 times and 1.3 times the first height (hg1) at a first end proximate the first grating region (1221), the height of the blank region (224) being between 0.7 times and 1.3 times the second height (hg2) at a second end proximate the second grating region (1222), the height of the blank region (224) varying between the height at the first end and the height at the second end.

8. The optical waveguide of claim 1, wherein, The grating region includes a first grating region (1221) and a second grating region (1222), the first grating region (1221) and the second grating region (1222) have varying heights, the blank region (224) is arranged between the first grating region (1221) and the second grating region (1222), one end of the blank region (224) close to the first grating region (1221) is a first end, one end of the blank region (224) close to the second grating region (1222) is a second end, the first grating region (1221) has a first height (hg1) at an end close to the first end, the second grating region (1222) has a second height (hg2) at an end close to the second end, the first height (hg1) is less than the second height (hg2), and a difference between the first height (hg1) and the second height (hg2) is less than or equal to 30% of the second height (hg2); wherein the height of the blank region (224) is between 0.7 times the second height (hg2) and 1.3 times the first height (hg1).

9. The optical waveguide of claim 1, wherein, The grating region includes a first grating region (1221) and a second grating region (1222), the first grating region (1221) and the second grating region (1222) have varying heights, the blank region (224) is arranged between the first grating region (1221) and the second grating region (1222), one end of the blank region (224) close to the first grating region (1221) is a first end, one end of the blank region (224) close to the second grating region (1222) is a second end, the first grating region (1221) has a first height (hg1) at an end close to the first end, the second grating region (1222) has a second height (hg2) at an end close to the second end, the first height (hg1) is less than the second height (hg2); wherein the height of the first end is between 0.7 times and 1.3 times the first height (hg1), the height of the second end is between 0.7 times and 1.3 times the second height (hg2), and the height of the blank region (224) varies between the height of the first end and the height of the second end.

10. An augmented reality display device, characterized by An optical waveguide comprising any one of claims 1 to 9. An optical waveguide comprising any one of claims 1 to 9.

Images