Waveguide optical device and display equipment

Abstract

The present invention discloses a waveguide optical device, comprising a waveguide body. A first optical element is disposed in a first region of the waveguide body. The first optical element couples light into the waveguide body and expands the light in at least two dimensions within the waveguide body. A second optical element is disposed in a second region of the waveguide body, coupling light propagating within the waveguide body out of the waveguide body. The first optical element in the first region of the waveguide body of the present waveguide optical device is capable of coupling light into the waveguide body and expanding the light in at least two dimensions within the waveguide body. This allows the light to propagate within the waveguide body through different dimensions and reach the second region. This increases the number of outcoupled light beams within the same area of ​​the second region, thereby helping to improve the uniformity of the output image. The present invention also discloses a display device.

Description

Technical Field

[0001] The present invention relates to the technical field of optical devices, and in particular to a waveguide optical device. The present invention also relates to a display device. Background Art

[0002] Among the hardware implementation solutions for augmented reality display, grating waveguide is a mainstream technical solution. Existing grating waveguide solutions have the following two configurations:

[0003] The first method is to use three gratings, please refer to Figure 1 As shown, the input light is coupled into the slab waveguide 10 through the grating 11, so that it meets the total reflection condition of the slab waveguide 10. The pupil is expanded laterally through the grating 12. Each time the light encounters the grating 12, it will diffract, generating diffraction orders that propagate toward the grating 13 and diffraction orders that continue to propagate backward, thereby achieving the expansion of the light in the horizontal direction; the light propagating toward the grating 13 will diffract each time it encounters the grating 13, generating diffraction orders that are output to the outside of the slab waveguide 10 and diffraction orders that continue to propagate downward, thereby achieving the expansion of the light in the vertical direction through the grating 13. Another method is to use two gratings, please refer to Figure 2 As shown, the input light is coupled into the slab waveguide 20 through the grating 21, and the two-dimensional grating 22 simultaneously performs the functions of expansion and outcoupling in two dimensions.

[0004] However, the above two solutions have a common problem: the amount of output beam is different when the input light is at a smaller incident angle and when the input light is at a larger incident angle. When the incident angle of the input light is larger, the diffraction angle increases, so the distance between the two coupled beams increases after the grating pupil is expanded, resulting in a decrease in the output beam within the same area. For example, please refer to Figure 3(a) to Figure 4(b) , Figure 3(a) and Figure 3(b) are Figure 2 The beam propagation of the grating waveguide scheme shown in Figure 4(a) and Figure 4(b) is shown in Figure 4(a) when the incident angle is 0 degrees. Figure 2 The grating-waveguide solution shown here shows beam propagation at an incident angle greater than 0 degrees (larger incident angles). The circles within the grating 22 in Figures 3(b) and 4(b) indicate the areas where the beam emerges. Comparing the two cases, it can be seen that at smaller incident angles, the area within the outcoupling grating 22 where the beam emerges is larger, while at larger incident angles, the area within the outcoupling grating 22 where the beam emerges is smaller. This indicates that with existing grating-waveguide solutions, the amount of output beam within the same area varies at different incident angles, resulting in uneven output images at different input angles, which affects imaging quality. Summary of the Invention

[0005] The present invention aims to provide a waveguide optical device that can improve the uniformity of output images when input light has different incident angles compared to the prior art. The present invention also provides a display device.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A waveguide optical device includes a waveguide body, a first optical element disposed in a first region of the waveguide body, the first optical element coupling light into the waveguide body and causing the light to expand in at least two dimensions within the waveguide body, and a second optical element disposed in a second region of the waveguide body coupling light propagating within the waveguide body out of the waveguide body.

[0008] Preferably, the first optical element comprises periodically arranged structural units, and the structural units are inclined relative to the surface normal of the first region of the waveguide body.

[0009] Preferably, the first optical element includes periodically arranged structural units, the structural units are cylindrical in shape, and the structural units include a top surface and a bottom surface, the top surface and the bottom surface have the same shape, and the top surface and the bottom surface have the same or different sizes.

[0010] Preferably, the second optical element disposed in the second region of the waveguide body enables light propagating along a single dimension in the waveguide body to expand in at least two dimensions.

[0011] Preferably, the first optical element includes structural units periodically arranged along two directions, and the second optical element includes structural units periodically arranged along two directions.

[0012] Preferably, the arrangement direction of the periodic arrangement of the structural units of the first optical element is consistent with the arrangement direction of the periodic arrangement of the structural units of the second optical element.

[0013] Preferably, the periods of the structural units of the first optical element along different directions are the same, or the periods of the structural units of the second optical element along different directions are the same.

[0014] Preferably, the structural units of the first optical element have the same period along different directions, the structural units of the second optical element have the same period along different directions, and the period of the structural units of the first optical element in each direction is the same as the period of the structural units of the second optical element in each direction.

[0015] Preferably, the second optical element comprises periodically arranged structural units, and the structural units are inclined relative to the surface normal of the second region of the waveguide body.

[0016] A display device comprises the waveguide optical device described above.

[0017] As can be seen from the above technical solution, the waveguide optical device provided by the present invention includes a waveguide body, a first optical element is arranged in a first region of the waveguide body, the first optical element couples light into the waveguide body and expands the light in at least two dimensions within the waveguide body, and a second optical element is arranged in a second region of the waveguide body to couple light propagating within the waveguide body out of the waveguide body.

[0018] In the waveguide optical device of the present invention, the first optical element in the first region of the waveguide body can couple light into the waveguide body and expand the light in at least two dimensions within the waveguide body. This allows the light to propagate through different dimensions within the waveguide body and reach the second region. This increases the number of locations where light enters the second region, increases the number of outgoing light beams within the same area of ​​the second region, and helps improve the uniformity of the output image when the input light has different incident angles.

[0019] The present invention provides a display device that can achieve the above beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A schematic diagram of an existing grating waveguide solution;

[0022] Figure 2 A schematic diagram of another existing grating waveguide solution;

[0023] Figure 3(a) and Figure 3(b) are Figure 2 The beam propagation of the grating waveguide scheme shown is at an incident angle of 0 degrees;

[0024] Figure 4(a) and Figure 4(b) are Figure 2 The beam propagation of the grating waveguide scheme shown is when the incident angle is greater than 0 degrees;

[0025] Figure 5 A schematic diagram of a waveguide optical device provided by an embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of a structural unit of a first optical element according to an embodiment of the present invention;

[0027] Figure 74 is a graph showing the change in diffraction efficiency of (-1, 0) order diffraction light as a function of the tilt angle ζ, calculated by simulation, when the first optical element of the waveguide optical device according to an embodiment of the present invention uses the structural unit arrangement shown in FIG. 4 ;

[0028] Figure 8 Schematic diagram of a structural unit of a second optical element according to an embodiment of the present invention;

[0029] Figure 9 Schematic diagram of a propagation light path of a waveguide optical device according to an embodiment of the present invention;

[0030] Figure 10 FIG. 4 is a side view of a waveguide optical device according to another embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0032] An embodiment of the present invention provides a waveguide optical device, comprising a waveguide body, wherein a first optical element is disposed in a first region of the waveguide body, the first optical element coupling light into the waveguide body and expanding the light in at least two dimensions within the waveguide body, and a second optical element is disposed in a second region of the waveguide body coupling light propagating within the waveguide body out of the waveguide body.

[0033] The waveguide body is a waveguide structure capable of guiding light propagation. When light is incident on the first optical element in the first region, the first optical element couples the light into the waveguide body and expands the light in at least two dimensions within the waveguide body. Expanding the light in at least two dimensions means expanding light propagating in a single dimension to propagate in at least two dimensions. When the light propagating along the waveguide body reaches the second region, it is coupled out of the waveguide body through the second optical element.

[0034] In the waveguide optical device of this embodiment, the first optical element in the first region of the waveguide body can couple light into the waveguide body and expand the light in at least two dimensions within the waveguide body, so that the light propagates through different dimensions within the waveguide body and reaches the second region. This increases the number of locations where light enters the second region, and can increase the number of outgoing light beams within the same area of ​​the second region, thereby helping to improve the uniformity of the output image when the input light has different incident angles.

[0035] The waveguide optical device is described in detail below with reference to specific embodiments and accompanying drawings.

[0036] Please refer to Figure 5 , Figure 5 Schematic diagram of a waveguide optical device according to an embodiment of the present invention. The waveguide optical device according to the present embodiment includes a waveguide body 300, wherein a first optical element 301 is provided in a first region of the waveguide body 300. When input light is incident on the first optical element 301, diffraction occurs, causing the light to be coupled into the waveguide body 300.

[0037] The first optical element 301 couples light into the waveguide body 300 and expands the light in at least two dimensions within the waveguide body 300. In one embodiment, the first optical element 301 includes structural units periodically arranged along two directions. Figure 6 , Figure 6 This is a schematic diagram of the structural units of a first optical element of this embodiment. As shown in the figure, the first optical element 301 is provided with structural units 303 periodically arranged along two directions. The structural units 303 are periodically arranged along two directions, specifically direction 1 and direction 2. When the input light is incident on the structural units 303 in the first area, it will expand and propagate along two dimensions.

[0038] Optionally, the periods of the structural units of the first optical element 301 along different periodic arrangement directions may be the same, and the period of the structural units refers to the distance between two adjacent structural units along the arrangement direction of the structural units. Figure 6 The periods of the structural unit 303 along direction 1 and direction 2 are d 11 and d 12 , you can set d 11 =d 12 , which facilitates design and production. However, this is not limiting. In practical applications, the periodicity of the structural units of the first optical element 301 along two directions can be different to achieve other special functions. Furthermore, the angle θ between the two periodic arrangement directions of the structural units can be set based on actual conditions such as application needs and design requirements. Typically, the value of θ ranges from 30° to 90°.

[0039] Preferably, the structural units of the first optical element 301 can be tilted relative to the surface normal of the first region of the waveguide body 300. Through this structural design, the asymmetry of the shape of the structural units of the first optical element is utilized to improve the coupling efficiency. Figure 7 , Figure 7This graph shows the diffraction efficiency of the (-1, 0)-order diffracted light as a function of the tilt angle ζ, calculated for the first optical element of a waveguide optical device using the structural unit arrangement shown in FIG4 . Tilt angle ζ refers to the angle between the structural unit 303 and the surface normal of the first region of the waveguide body. It can be seen that the diffraction efficiency of the (-1, 0)-order diffracted light increases as the tilt angle ζ increases. Therefore, by tilting the structural units of the first optical element, the efficiency of light coupling into the waveguide can be improved, thereby enhancing the energy utilization of the waveguide optical device.

[0040] Optionally, the shape of the structural unit included in the first optical element 301 can be cylindrical. More specifically, the cylindrical structural unit may include a top surface and a bottom surface, and the top surface and the bottom surface may not be parallel, or the top surface and the bottom surface of the structural unit may be parallel. In actual applications, it can be set accordingly according to application needs and design requirements.

[0041] Furthermore, the top and bottom surfaces of the structural units included in the first optical element 301 can have the same shape. For example, the top and bottom surfaces can both be circular, elliptical, or triangular, but are not limited thereto. In practical applications, the top and bottom surfaces of the structural units can also adopt other shapes. If the structural units of the first optical element 301 are cylindrical, including mutually parallel top and bottom surfaces, both of which are circular and of the same size, its structural parameters include the diameter R of the top and bottom surfaces, the height H, and the sidewall inclination angle ζ. The value range of each parameter can be R: 0.1d ~ 0.5d, where d represents the period of the structural unit (the period of the structural unit along the two periodic arrangement directions is consistent), H: 100nm ~ 1000nm, and ζ: 5° ~ 50°.

[0042] If the structural unit of the first optical element 301 is cylindrical, including mutually parallel top and bottom surfaces, both of which are elliptical and have the same shape and size, its structural parameters include the ellipse major axis a, the ellipse minor axis b, the height H, and the sidewall inclination angle ζ. The value range of each parameter can be a: 0.1d to 0.5d, b: 0.1d to 0.4d, d represents the period of the structural unit (the period of the structural unit along the two periodic arrangement directions is consistent), H: 100nm to 1000nm, and ζ: 5° to 50°.

[0043] If the structural unit of the first optical element 301 is cylindrical, including a top surface and a bottom surface that are parallel to each other, both of which are triangular and have the same size, its structural parameters include the side length a, height H, and sidewall inclination angle ζ of the triangle. The value range of each parameter can be a: 0.1d to 0.5d, d represents the period of the structural unit (the period of the structural unit along the two periodic arrangement directions is consistent), H: 100nm to 1000nm, and ζ: 5° to 50°.

[0044] Optionally, the top and bottom surfaces of the structural unit of the first optical element 301 may have different shapes. For example, the structural unit is cylindrical, including a top surface and a bottom surface that are parallel to each other and both are circular, but the diameters of the top and bottom surfaces are different. Its structural parameters include the top surface diameter R1, the bottom surface diameter R2, the height H, and the sidewall inclination angle ζ. The value range of each parameter can be R1: 0.1d ~ 0.5d, R2: 0.1d ~ 0.5d, d represents the period of the structural unit (the period of the structural unit along the two periodic arrangement directions is consistent), H: 100nm ~ 1000nm, ζ: 5° ~ 50°.

[0045] In practical applications, the shapes of the structural units of the first optical element 301 are not limited to the specific embodiments given above, and other shapes may also be used, all of which are within the protection scope of the present invention.

[0046] In the waveguide optical device of this embodiment, the first optical element in the first region of the waveguide body can couple light into the waveguide body and expand the light in at least two dimensions within the waveguide body. This allows the light coupled into the waveguide body to propagate through different dimensions within the waveguide body and reach the second region. This can improve the beam filling rate in the second region of the waveguide body and make the output light of the waveguide optical device more uniform.

[0047] Furthermore, in the waveguide optical device of this embodiment, reference may be made to Figure 5 As shown, a second optical element 302 is provided in the second region of the waveguide body 300 for coupling the light propagating in the waveguide body 300 out of the waveguide body 300. The light coupled into the waveguide body 300 propagates along the waveguide body 300, and when the light reaches the second region, it is coupled out of the waveguide body 300 through the second optical element 302.

[0048] Preferably, the second optical element 302 expands light propagating along a single dimension within the waveguide body 300 into at least two dimensions. When a beam of light propagating along a single dimension within the waveguide body 300 reaches the second region, it is coupled out of the waveguide body 300 through the second optical element 302. Simultaneously, the second optical element 302 expands the light to propagate along at least two dimensions. Therefore, the second optical element in the second region of the waveguide body can further improve the beam filling factor in the second region of the waveguide body, thereby making the output light of the waveguide optical device more uniform.

[0049] In one embodiment, the second optical element 302 disposed in the second region of the waveguide body includes structural units periodically arranged along two directions. Figure 8 , Figure 8This is a schematic diagram of a structural unit of a second optical element of this embodiment. As shown in the figure, the second optical element 302 includes structural units 308 arranged periodically along two directions. The structural units 308 are periodically arranged along the two directions, specifically direction 3 and direction 4. Please refer to Figure 9 , Figure 9 This is a schematic diagram of the propagation light path of a waveguide optical device of this embodiment. When light from the first region propagates to the second region, the light is incident on the periodically arranged structural units 308 of the second optical element 302, causing diffraction to couple the light out of the waveguide body 300. At the same time, the light propagating along a single dimension within the waveguide body 300 is expanded to propagate along two dimensions.

[0050] Optionally, the period of the structural units of the second optical element 302 along different periodic arrangement directions may be the same, and the period of the structural units refers to the distance between two adjacent structural units along the arrangement direction of the structural units. Figure 8 The periods of the structural unit 308 along direction 3 and direction 4 are d 21 and d 22 , you can set d 21 =d 22 , which facilitates design and production. However, this is not limiting. In practical applications, the periodicity of the structural units of the second optical element 302 along two directions can be different to achieve other special functions. Furthermore, the angle θ between the two periodic arrangement directions of the structural units can be set based on actual conditions such as application needs and design requirements. Typically, the value of θ ranges from 30° to 90°.

[0051] Preferably, the structural unit of the second optical element 302 may be arranged to be inclined relative to the surface normal of the second region of the waveguide body 300. Figure 10 , Figure 10 This is a side view of another waveguide optical device according to the present embodiment. A first optical element and a second optical element are respectively arranged in the first and second regions of the waveguide body 300, wherein the first optical element includes structural units 303 arranged periodically along two directions, and the second optical element includes structural units 309 arranged periodically along two directions. The structural units 303 arranged in the first region of the waveguide body 300 are inclined relative to the surface normal of the first region, and the structural units 309 in the second region of the waveguide body 300 are inclined relative to the surface normal of the second region. Through this structural design, the asymmetry of the shape of the structural units is utilized to improve the coupling efficiency, thereby improving the overall energy utilization rate of the waveguide optical device.

[0052] Preferably, the arrangement direction of the periodic arrangement of the structural units of the first optical element 301 is consistent with the arrangement direction of the periodic arrangement of the structural units of the second optical element 302. Figure 6 and Figure 8 , if Figure 6 The structural unit arrangement shown and Figure 8 When the structural units are arranged in the same waveguide optical device, it is preferred that directions 1 and 3 are consistent, and directions 2 and 4 are consistent. This structural design can avoid unnecessary stray light in the output image of the waveguide optical device, thereby improving imaging quality.

[0053] Preferably, the period of the structural units of the first optical element 301 along different directions is the same, the period of the structural units of the second optical element 302 along different directions is the same, and the period of the structural units of the first optical element 301 along each direction is the same as the period of the structural units of the second optical element 302 along each direction. Figure 6 and Figure 8 , if Figure 6 The structural unit arrangement shown and Figure 8 When the structural units shown are arranged and applied to the same waveguide optical device, it is preferred to set d 11 =d 12 =d 21 =d 22 However, the present invention is not limited thereto, and in practical applications, the period of the first optical element structural unit and the period of the second optical element structural unit may be set to be different to achieve other functions.

[0054] In a specific embodiment of the present waveguide optical device, the structural units of the first optical element 301 of the waveguide body have the same period along different directions, the structural units of the second optical element 302 have the same period along different directions, the period of the structural units of the first optical element 301 along each direction is the same as the period of the structural units of the second optical element 302 along each direction, and the value range of the period is 200nm to 1000nm. The two arrangement directions of the periodic arrangement of the structural units of the first optical element 301 are respectively the same as the two arrangement directions of the periodic arrangement of the structural units of the second optical element 302, and the angle between the two arrangement directions is in the range of 30° to 90°.

[0055] Therefore, in the waveguide optical device of this embodiment, the first optical element of the waveguide body can expand light in at least two dimensions within the waveguide body, performing pre-pupil expansion, so that the light propagates through different dimensions within the waveguide body and reaches the second region; the second optical element arranged in the second region of the waveguide body can expand light propagating along a single dimension within the waveguide body in at least two dimensions, further perform pupil expansion, and couple it out of the waveguide, thereby increasing the number of coupled-out light beams within the same area of ​​the second region of the waveguide body, and helping to improve the uniformity of the output image when the input light has different incident angles.

[0056] Correspondingly, an embodiment of the present invention further provides a display device, comprising the waveguide optical device described above.

[0057] The display device of this embodiment adopts a waveguide optical device. The first optical element in the first region of the waveguide body can couple light into the waveguide body and expand the light in at least two dimensions within the waveguide body, so that the light propagates through different dimensions within the waveguide body and reaches the second region. This increases the number of entry points for light propagation into the second region, and can increase the number of light beams coupled out within the same area of ​​the second region, thereby helping to improve the uniformity of the output image when the input light has different incident angles.

[0058] The above describes in detail the waveguide optical device and display apparatus provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is intended only to facilitate understanding of the method and core concepts of the present invention. It should be noted that those skilled in the art will be able to make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications fall within the scope of protection of the claims.

Claims

1. A waveguide optical device, characterized in that: The invention comprises a waveguide body, wherein a first optical element is provided in a first region of the waveguide body, and a second optical element is provided in a second region of the waveguide body; The first optical element includes structural units periodically arranged along two directions, and the structural units are inclined relative to the surface normal of the first region of the waveguide body. The first optical element couples light into the waveguide body and expands the light in at least two dimensions within the waveguide body, so that the light propagates through different dimensions within the waveguide body and reaches the second region, thereby increasing the number of locations where light enters the second region. The second optical element includes structural units periodically arranged along two directions, and the structural units are inclined relative to the surface normal of the second region of the waveguide body. The second optical element disposed in the second region of the waveguide body causes light propagating along a single dimension within the waveguide body to expand in at least two dimensions, and the second optical element couples the light propagating within the waveguide body out of the waveguide body. The arrangement direction of the periodic arrangement of the structural units of the first optical element is consistent with the arrangement direction of the periodic arrangement of the structural units of the second optical element.

2. The waveguide optical device according to claim 1, wherein The first optical element includes periodically arranged structural units, each structural unit is cylindrical in shape and includes a top surface and a bottom surface, the top surface and the bottom surface have the same shape, and the top surface and the bottom surface have the same or different sizes.

3. The waveguide optical device according to claim 1, wherein The periods of the structural units of the first optical element along different directions are the same, or the periods of the structural units of the second optical element along different directions are the same.

4. The waveguide optical device according to claim 1, wherein The structural units of the first optical element have the same period in different directions, the structural units of the second optical element have the same period in different directions, and the period of the structural units of the first optical element in each direction is the same as the period of the structural units of the second optical element in each direction.

5. A display device, characterized in that: A waveguide optical device comprising the waveguide optical device according to any one of claims 1 to 4.

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