Optical waveguide device and near-to-eye display device

Abstract

The invention discloses an optical waveguide device and near-to-eye display equipment, and relates to the technical field of optics, the optical waveguide device comprises a coupling-in structure, a total reflection structure, a turning structure and a coupling-out structure; the total reflection structure comprises a total reflection surface, and at least part of light entering the optical waveguide device through the coupling-in structure is subjected to total reflection through the total reflection surface, is turned to the turning structure, is turned to the coupling-out structure again through the turning structure, and is coupled out to human eyes through the coupling-out structure. By arranging the total reflection structure, the high degree of freedom of the design of the optical waveguide device can be ensured while the field angle and the eye movement range can be remarkably improved, so that the optical waveguide device better conforms to the form of glasses.

Description

Technical Field

[0001] The present invention relates to the field of optical technologies, and in particular, to an optical waveguide device and a near-eye display device. Background Art

[0002] Augmented reality (AR) technology is a technology that combines virtual information generated by a computer with the real environment, and can superimpose virtual information on the real world in real time and dynamically, thereby enhancing the user's perception and understanding of the real world.

[0003] An AR optical waveguide is an optical device used in an augmented reality near-eye display device. It can project a virtual image directly into the user's eyes, while ensuring that the user's view of the real world is not blocked. The conical range formed by the human eye and the virtual image seen is called the field of view angle, the distance between the human eye and the display device when the human eye can see the entire virtual image is called the exit pupil distance, and the range within which the human eye can move when it can see the entire virtual image at a certain exit pupil distance is called the eye movement range.

[0004] To ensure that the optical waveguide device better conforms to the shape of glasses, special designs need to be made for the optical path inside the waveguide plate. How to significantly improve the field of view angle and the eye movement range while ensuring a high degree of freedom in the design of the optical waveguide device is a major difficulty faced by current AR optical waveguides. Summary of the Invention

[0005] The present invention provides an optical waveguide device and a near-eye display device, which can significantly improve the field of view angle and the eye movement range while ensuring a high degree of freedom in the design of the optical waveguide device, making the optical waveguide device better conform to the shape of glasses.

[0006] In a first aspect, an embodiment of the present invention provides an optical waveguide device, including an input coupling structure, a total reflection structure, a turning structure, and an output coupling structure; The total reflection structure includes a total reflection surface. At least part of the light entering the optical waveguide device through the input coupling structure is totally reflected by the total reflection surface and turned to the turning structure, then turned again to the output coupling structure by the turning structure, and then coupled out to the human eye through the output coupling structure.

[0007] Optionally, the total reflection structure includes a total reflection compensation sheet, and the refractive index of the total reflection compensation sheet is less than the refractive index of the waveguide substrate, so that the surface of the total reflection structure close to the input coupling structure forms the total reflection surface.

[0008] Optionally, the total reflection structure includes a total reflection compensation sheet, and a filling material or a total reflection film layer located on the side of the total reflection compensation sheet close to the input coupling structure; The refractive indices of the filling material and the total reflection film layer are both smaller than that of the waveguide substrate, so that a total reflection surface is formed on one side of the total reflection structure close to the coupling structure.

[0009] Optionally, the optical waveguide device is an arrayed waveguide, and the optical waveguide device further includes a first surface and a second surface arranged in parallel. The coupling structure, the total reflection structure, the turning structure, and the coupling-out structure are all located between the first surface and the second surface; The turning structure includes a plurality of mutually parallel first splitting surfaces, and the coupling-out structure includes a plurality of mutually parallel second splitting surfaces; The total reflection surface and the first splitting surface are perpendicular to the first surface, and the second splitting surface has a first preset angle that is not perpendicular to the first surface.

[0010] Optionally, the total reflection surface and the second splitting surface both extend in a first direction, and the first splitting surface extends in a second direction; At least part of the light entering the optical waveguide device through the coupling structure is totally reflected by the total reflection surface and then turned, and then expanded by the first splitting surface and turned again, and then coupled out to the human eye through the second splitting surface; wherein, the first direction and the second direction are both parallel to the first surface, and the first direction and the second direction intersect.

[0011] Optionally, the total reflection surface and the first splitting surface both extend in a third direction, and the second splitting surface extends in a fourth direction; a part of the first splitting surface of the turning structure exists on the optical path transmission path between the coupling structure and the total reflection surface; The light entering the optical waveguide device through the coupling structure first passes through part of the first splitting surface, then is totally reflected by the total reflection surface and turned, and then expanded by a plurality of the first splitting surfaces and turned again, and then coupled out into the human eye through the second splitting surface; wherein, the third direction and the fourth direction are both parallel to the first surface, and the third direction and the fourth direction intersect.

[0012] Optionally, the total reflection surface extends in a fifth direction, the first splitting surface extends in a sixth direction, and the second splitting surface extends in a seventh direction; At least part of the light entering the optical waveguide device through the coupling structure is totally reflected by the total reflection surface and then turned, and then expanded by the first splitting surface and turned again, and then coupled out to the human eye through the second splitting surface; wherein, the fifth direction, the sixth direction, and the seventh direction are all parallel to the first surface, and the fifth direction, the sixth direction, and the seventh direction intersect pairwise.

[0013] Optionally, the coupling-in structure includes a mirror or a prism.

[0014] Optionally, the optical waveguide device is a diffractive optical waveguide, and the coupling-in structure, the turning structure, and the coupling-out structure all include diffraction gratings.

[0015] In a second aspect, an embodiment of the present invention further provides a near-eye display device, including the optical waveguide device according to any one of the embodiments in the first aspect.

[0016] An embodiment of the present invention provides an optical waveguide device and a near-eye display device. By providing a total reflection structure, at least part of the light entering the optical waveguide device through the coupling-in structure can be totally reflected by the total reflection surface and turned to the turning structure, then turned again by the turning structure to the coupling-out structure, and then coupled out to the human eye through the coupling-out structure. The relative angles of the coupling-in structure, the total reflection surface, the turning structure, and the coupling-out structure can be adjusted according to specific design requirements. In this way, while expanding the field of view angle and the eye movement range, the horizontal distance between the coupling-in and coupling-out centers can be increased and the longitudinal distance can be reduced, and at the same time, the high degree of freedom in the design of the optical waveguide device can be ensured, making the optical waveguide device more in line with the form of glasses.

[0017] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 is an optical path diagram of an optical waveguide device in the prior art; Figure 2 is a schematic structural diagram of an optical waveguide device provided by an embodiment of the present invention; Figure 3 is Figure 2 the optical path diagram of the optical waveguide device in Figure 4 is a schematic structural diagram of another optical waveguide device provided by an embodiment of the present invention; Figure 5 is Figure 4 the optical path diagram of the optical waveguide device in Figure 6 is a schematic structural diagram of another optical waveguide device provided by an embodiment of the present invention; Figure 7 is Figure 6 the optical path diagram of the optical waveguide device in Specific embodiments

[0020] In order to enable those skilled in the art to better understand the solution of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0021] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0022] Figure 1 is the optical path diagram of an optical waveguide device in the prior art. Referring to Figure 1 , the optical waveguide device includes: an input coupling structure 110, a turning structure 120, and an output coupling structure 130. The light emitted by the image projector 200 enters the optical waveguide device through the input coupling structure 110, is turned to the output coupling structure 130 through the turning structure 120, and then is coupled out to the human eye through the output coupling structure 130. The two-dimensional array optical waveguide of this prior art uses the principle of geometric optics, and the light realizes input coupling, pupil expansion, and output coupling through refraction and reflection. The input coupling center in the vertical direction y is significantly higher than the output coupling center, and the distance between the input coupling center and the output coupling center in the horizontal direction x is too short. Moreover, the larger the field of view angle, the larger the turning structure 120 needs to be, which is not suitable for being made into a glasses form.

[0023] In order to significantly improve the field of view angle and eye movement range while ensuring a high degree of freedom in the design of the optical waveguide device, making the optical waveguide device more conform to the glasses form, the embodiments of the present invention provide an optical waveguide device, Figure 2 is the structural schematic diagram of an optical waveguide device provided by the embodiments of the present invention, Figure 3 is Figure 2 the optical path diagram of the optical waveguide device in Figure 2 and Figure 3, the optical waveguide device includes an input coupling structure 110, a total reflection structure 140, a turning structure 120, and an output coupling structure 130; the total reflection structure 140 includes a total reflection surface 141. At least part of the light entering the optical waveguide device through the input coupling structure 110 is totally reflected by the total reflection surface 141 and turned towards the turning structure 120, then turned again by the turning structure 120 towards the output coupling structure 130, and then coupled out to the human eye through the output coupling structure 130.

[0024] Specifically, the optical waveguide device can be an arrayed waveguide or a diffractive waveguide, and the whole optical waveguide device is made of a transparent material. The total reflection surface 141 can be constructed in various ways, as long as it can make at least part of the light entering the optical waveguide device through the input coupling structure 110 be totally reflected by the total reflection surface 141 and turned towards the turning structure 120. In the embodiment of the present invention, taking the arrayed waveguide as an example, the light entering the optical waveguide device through the input coupling structure 110 is totally reflected and transmitted, and all the field-of-view light hitting the total reflection surface 141 satisfies the total reflection condition. After being reflected by the total reflection surface 141, the light turns and propagates towards the turning structure 120 by total reflection.

[0025] In the embodiment of the present invention, the total reflection structure 140 is provided. Therefore, the relative angles of the input coupling structure 110, the total reflection surface 141, the turning structure 120, and the output coupling structure 130 can be adjusted according to specific design requirements. In this way, while expanding the field-of-view angle and the eye movement range, the horizontal distance between the input and output centers can be increased and the longitudinal distance can be decreased, and at the same time, the high degree of freedom in the design of the optical waveguide device is ensured, making the optical waveguide device more conform to the form of glasses.

[0026] Optionally, in an embodiment, the total reflection structure 140 includes a total reflection compensation sheet, and the refractive index of the total reflection compensation sheet is less than the refractive index of the waveguide substrate, so that the surface of the total reflection structure 140 close to the input coupling structure 110 forms the total reflection surface 141.

[0027] Optionally, in an embodiment, the total reflection structure 140 includes a total reflection compensation sheet, and a filling material or a total reflection film layer located on the side of the total reflection compensation sheet close to the input coupling structure 110; the refractive indices of the filling material and the total reflection film layer are both less than the refractive index of the waveguide substrate, so that the side of the total reflection structure 140 close to the input coupling structure 110 forms the total reflection surface 141.

[0028] It can be understood that the total reflection surface 141 can be constructed in various ways. It can be made that the refractive index of the total reflection compensation sheet is less than the refractive index of the waveguide substrate connected to it, and the total reflection surface 141 is directly formed at the connection interface. Or a low-refractive-index material can be filled at the junction of the total reflection compensation sheet and the waveguide substrate, or a low-refractive-index film layer can be plated on the surface of the junction, so that the light entering the optical waveguide device from the input coupling structure 110 undergoes total reflection at the total reflection surface 141 and thus turns.

[0029] It should be noted that the total reflection compensation film can also play a protective role. Since the surface of the optical waveguide device needs to be polished, if the total reflection surface 141 is not protected by the compensation film, defects such as chipping will occur at the edge, affecting the display effect.

[0030] Optionally, continuing to refer to Figure 2 and Figure 3 , in one embodiment, the optical waveguide device is an array optical waveguide. The optical waveguide device further includes a first surface and a second surface arranged in parallel. The coupling structure 110, the total reflection structure 140, the turning structure 120, and the coupling-out structure 130 are all located between the first surface and the second surface; the turning structure 120 includes a plurality of mutually parallel first splitting surfaces 121, and the coupling-out structure 130 includes a plurality of mutually parallel second splitting surfaces 131; the total reflection surface 141 and the first splitting surface 121 are perpendicular to the first surface, and the second splitting surface 131 has a first preset angle that is not perpendicular to the first surface.

[0031] Specifically, the number of the first splitting surfaces 121 and the second splitting surfaces 131 can be designed according to the requirements of the field of view angle and the eye movement range, as long as the effective light propagation regions for turning and pupil expansion of the turning structure and the coupling-out structure are ensured. The first splitting surface 121 has the characteristic of partial transmission and partial reflection. The first splitting surface 121 is embedded in the optical waveguide device and is perpendicular to the first surface A and the second surface B of the optical waveguide device, and is responsible for expanding the pupil of the light reflected and turned by the total reflection surface 141 and turning it again. The second splitting surface 131 has the characteristic of partial transmission and partial reflection, is embedded in the optical waveguide device, and has a first preset angle that is not perpendicular to the first surface A and the second surface B, and is responsible for coupling out the light that has been expanded and turned by the turning structure 120 into the human eye through the principles of reflection and refraction. Among them, the first preset angle can be freely set as long as the second splitting surface 131 can couple out the light that has been expanded and turned by the turning structure 120 into the human eye through the principles of reflection and refraction.

[0032] Optionally, in one embodiment, continuing to refer to Figure 2 and Figure 3 , the total reflection surface 141 and the second splitting surface 131 both extend along a first direction, and the first splitting surface 121 extends along a second direction; at least part of the light entering the optical waveguide device through the coupling structure 110 is totally reflected by the total reflection surface 141 and then turned, and after being expanded and turned again by the first splitting surface 121, it is coupled out to the human eye through the second splitting surface 131; wherein, both the first direction and the second direction are parallel to the first surface A, and the first direction and the second direction intersect.

[0033] It can be understood that, due to the setting of the total reflection surface 141, the relative angles of the light coupling structure 110, the total reflection surface 141, the turning structure 120, and the light output structure can be adjusted according to specific design requirements. In this way, while expanding the viewing angle and the eye movement range, the distance between the light coupling center and the light output center in the horizontal direction x can be increased, and the distance in the vertical direction y can be decreased, which is more suitable for making glasses.

[0034] Figure 4 It is a schematic structural diagram of another optical waveguide device provided by an embodiment of the present invention. Figure 5 is Figure 4 the optical path diagram of the optical waveguide device in Figure 4 and Figure 5 In this case, the total reflection surface 141 and the first beam splitting surface 121 both extend along the third direction, and the second beam splitting surface 131 extends along the fourth direction; there is a part of the first beam splitting surface 121 of the turning structure 120 on the optical path transmission path between the light coupling structure 110 and the total reflection surface 141; the light entering the optical waveguide device through the light coupling structure 110 first passes through a part of the first beam splitting surface 121, then is totally reflected by the total reflection surface 141 and turns, and then after being expanded by multiple first beam splitting surfaces 121 and turning again, it is output through the second beam splitting surface 131 and enters the human eye; among them, both the third direction and the fourth direction are parallel to the first surface A, and the third direction and the fourth direction intersect.

[0035] It can be understood that Figure 4 the composition structure of the optical waveguide device in Figure 2 is similar to that of the optical waveguide device in Figure 4 but the arrangement method has changed. In Figure 5 the total reflection surface 141 and the first beam splitting surface 121 are parallel, and there is a first beam splitting surface 121 of the turning structure 120 on the optical path transmission path between the light coupling structure 110 and the total reflection surface 141, which can significantly reduce the process processing difficulty. Figure 3 The difference between the optical path diagram of

[0036] Figure 6 It is a schematic structural diagram of another optical waveguide device provided by an embodiment of the present invention. Figure 7 is Figure 6 the optical path diagram of the optical waveguide device in Figure 6 and Figure 7, the total reflection surface 141 extends along a fifth direction, the first beam splitting surface 121 extends along a sixth direction, and the second beam splitting surface 131 extends along a seventh direction; at least part of the light entering the optical waveguide device through the coupling structure 110 is totally reflected by the total reflection surface 141 and then turned, and after being expanded and turned again by the first beam splitting surface 121, it is coupled out to the human eye through the second beam splitting surface 131; wherein, the fifth direction, the sixth direction and the seventh direction are all parallel to the first surface A, and the fifth direction, the sixth direction and the seventh direction intersect pairwise.

[0037] It can be understood that in this embodiment, the total reflection surface 141 and the first beam splitting surface 121 are set to be non-parallel, as Figure 6 shown, where the relative angles of the coupling structure 110, the total reflection surface 141, the turning structure 120 and the coupling-out structure 130 are adjusted. Here, the total reflection surface 141 and the first beam splitting surface 121 in the turning structure 120 are not parallel, and there is no first beam splitting surface 121 of the turning structure 120 on the optical path transmission path between the coupling structure 110 and the total reflection surface 141. Through the arrangement adjustment, the longitudinal distance between the coupling center and the coupling-out center can be further reduced, and the design freedom is higher.

[0038] Optionally, on the basis of the above embodiment, the coupling structure 110 includes a mirror or a prism.

[0039] It can be understood that by using a mirror or a prism, the coupling structure 110 is responsible for coupling light into the optical waveguide device through the principles of reflection or refraction for total reflection propagation.

[0040] Optionally, in an embodiment, the optical waveguide device is a diffractive optical waveguide, and the coupling structure 110, the turning structure 120 and the coupling-out structure 130 all include diffraction gratings.

[0041] In summary, the optical waveguide device provided by the embodiment of the present invention can significantly improve the field of view angle and eye movement range while ensuring a high degree of freedom in the design of the optical waveguide device by setting the total reflection structure 140, making the optical waveguide device more conform to the form of glasses. In addition, by setting the total reflection compensation sheet, a protective effect can be achieved, which can protect the total reflection surface 141 and avoid affecting the display effect. The optical waveguide device can be an array optical waveguide or a diffractive optical waveguide. When the optical waveguide device is an array optical waveguide, due to the setting of the total reflection surface 141, the relative angles of the coupling structure 110, the total reflection surface 141, the turning structure 120, and the coupling-out structure can be adjusted according to specific design requirements. In this way, while expanding the field of view angle and eye movement range, the spacing between the coupling-in and coupling-out centers in the horizontal direction x can be increased and the spacing in the vertical direction y can be decreased, which is more suitable for making glasses. On this basis, by setting the total reflection surface 141 parallel to the first beam splitting surface 121, and there is a first beam splitting surface 121 of the turning structure 120 in the optical path transmission path between the coupling structure 110 and the total reflection surface 141, the process processing difficulty can be significantly reduced. By setting the total reflection surface 141 not parallel to the first beam splitting surface 121 in the turning structure 120, there is no first beam splitting surface 121 of the turning structure 120 in the optical path transmission path between the coupling structure 110 and the total reflection surface 141. Through layout adjustment, the longitudinal spacing between the coupling-in center and the coupling-out center can be further reduced, and the design freedom is higher.

[0042] The embodiment of the present invention also provides a near-eye display device, including the optical waveguide device of any of the above embodiments.

[0043] Since the near-eye display device provided by the embodiment of the present invention includes the optical waveguide device of any of the above embodiments, it has the same beneficial effects. For the content not described in detail in the embodiment of the present invention, reference can be made to the optical waveguide device provided in the above embodiments.

[0044] The above specific implementation manners do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An optical waveguide device, characterized in that: Including coupling-in structure, total reflection structure, turning structure and coupling-out structure; The total reflection structure includes a total reflection surface. At least part of the light entering the optical waveguide device through the coupling-in structure is totally reflected by the total reflection surface and turned to the turning structure, and then turned to the coupling-out structure again through the turning structure, and then coupled out to the human eye through the coupling-out structure.

2. The optical waveguide device according to claim 1, characterized in that The total reflection structure includes a total reflection compensation plate, the refractive index of which is smaller than the refractive index of the waveguide substrate, so that the surface of the total reflection structure close to the coupling structure forms the total reflection surface.

3. The optical waveguide device according to claim 1, characterized in that The total reflection structure includes a total reflection compensation plate, and a filling material or a total reflection film layer located on a side of the total reflection compensation plate close to the coupling structure; The refractive indexes of the filling material and the total reflection film layer are both smaller than the refractive index of the waveguide substrate, so that the total reflection surface is formed on a side of the total reflection structure close to the coupling-in structure.

4. The optical waveguide device according to claim 1, characterized in that The optical waveguide device is an array optical waveguide, and the optical waveguide device further comprises a first surface and a second surface arranged in parallel, and the coupling-in structure, the total reflection structure, the turning structure and the coupling-out structure are all located between the first surface and the second surface; The turning structure comprises a plurality of mutually parallel first light splitting surfaces, and the outcoupling structure comprises a plurality of mutually parallel second light splitting surfaces; The total reflection surface and the first light-splitting surface are perpendicular to the first surface, and the second light-splitting surface and the first surface have a first preset angle that is not perpendicular.

5. The optical waveguide device according to claim 4, characterized in that: The total reflection surface and the second light splitting surface both extend along the first direction, and the first light splitting surface extends along the second direction; At least part of the light entering the optical waveguide device through the coupling structure is redirected after total reflection by the total reflection surface, and then expanded and redirected again by the first beam splitting surface before being coupled out to the human eye through the second beam splitting surface; wherein the first direction and the second direction are both parallel to the first surface, and the first direction and the second direction intersect.

6. The optical waveguide device according to claim 4, characterized in that The total reflection surface and the first light splitting surface both extend along the third direction, and the second light splitting surface extends along the fourth direction; a portion of the first light splitting surface with the turning structure exists on the light transmission path between the coupling structure and the total reflection surface; The light entering the optical waveguide device through the coupling structure first passes through part of the first beam splitting surface, then is totally reflected by the total reflection surface and then turned, then is expanded by multiple first beam splitting surfaces and turned again, and then is coupled out through the second beam splitting surface and enters the human eye; wherein the third direction and the fourth direction are both parallel to the first surface, and the third direction and the fourth direction intersect.

7. The optical waveguide device according to claim 4, characterized in that The total reflection surface extends along a fifth direction, the first light splitting surface extends along a sixth direction, and the second light splitting surface extends along a seventh direction; At least part of the light entering the optical waveguide device through the coupling structure is totally reflected by the total reflection surface and then turned, and then expanded by the first beam splitting surface and turned again, and then coupled out to the human eye through the second beam splitting surface; wherein the fifth direction, the sixth direction and the seventh direction are all parallel to the first surface, and the fifth direction, the sixth direction and the seventh direction intersect each other.

8. The optical waveguide device according to claim 1, characterized in that The coupling-in structure includes a reflector or a prism.

9. The optical waveguide device according to claim 1, characterized in that The optical waveguide device is a diffraction optical waveguide, and the coupling-in structure, the turning structure and the coupling-out structure all include diffraction gratings.

10. A near-eye display device, characterized in that: The optical waveguide device comprises the optical waveguide device according to any one of claims 1 to 9.

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