Optical waveguide display system and near-eye display device

Abstract

The present invention provides an optical waveguide display system and a near-eye display device. The optical waveguide display system includes a waveguide substrate, a one-dimensional coupling grating, a recycling optical component, and an exit pupil expansion optical component. The one-dimensional coupling grating is arranged on one side of the waveguide substrate. The one-dimensional coupling grating is used to couple a target image source into the waveguide substrate, and generate a first target light beam that can be totally reflected and propagated in a first direction in the waveguide substrate, and generate 0th order diffraction light transmitted from the waveguide substrate; the recycling optical component is used to couple the 0th order diffraction light back into the waveguide substrate, and generate a second target light beam that can be totally reflected and propagated in a second direction in the waveguide substrate; the exit pupil expansion optical component is arranged on the waveguide substrate, and is used to expand the first target light beam and the second target light beam and couple them out of the waveguide substrate in a superimposed manner; wherein the first direction is different from the second direction. The present invention can improve the system field of view while multiplexing the 0th order diffraction light, and the difficulty of processing the optical waveguide is low.

Description

Technical Field

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

[0002] The optical waveguide display system mainly uses diffractive optical elements to couple the target image source into the waveguide matrix at a certain angle, and transmits it within the waveguide matrix based on the principle of total internal reflection. After one-dimensional or two-dimensional exit pupil expansion, it is coupled out from the waveguide matrix and transmitted to the human eye.

[0003] On the one hand, the coupling optical element in an optical waveguide display system typically uses a diffraction grating with a period on the wavelength or subwavelength scale (200nm to 500nm). In this case, the primary diffraction orders are typically 0th, +1st, and -1st. The +1st and -1st orders typically serve as the working orders of the waveguide matrix, while the 0th-order diffracted light typically transmits directly out of the waveguide matrix. Because most of the energy of the diffracted light is concentrated in the 0th order, it needs to be reused to improve the coupling efficiency of the optical waveguide display system. In the prior art, diffraction gratings are usually set on the upper and lower surfaces of the waveguide substrate to simultaneously diffract the coupled light and multiplex the 0th-order diffracted light. However, in order to ensure that the propagation directions of the +1st-order and / or -1st-order light diffracted by the diffraction gratings on both sides are completely consistent, the two sets of diffraction gratings need to be strictly aligned, and the grating directions cannot rotate relative to each other, otherwise it will affect the imaging effect. This places extremely high demands on the precision of the manufacturing equipment. At the same time, the grating structure is made on the upper and lower surfaces of the waveguide substrate, which usually requires the production of two nanoimprint templates, which will increase production costs and reduce product yield.

[0004] On the other hand, to improve the field of view (FOV) of optical waveguide display systems, existing technologies typically employ a dual-channel optical path design, specifically an input grating, two pupil expansion units, and an exit pupil unit. The input grating is used to decompose the target image source into two beams, which then travel through two main paths, expand through the pupil expansion units, and propagate to the exit pupil unit. Finally, they are superimposed and coupled out of the waveguide substrate. However, to achieve the purpose of decomposing the input light, the input grating must be a two-dimensional grating. Due to the limited number of adjustable parameters in the grating design, the diffraction efficiency of a two-dimensional grating is low. Furthermore, fabricating a two-dimensional grating structure on a waveguide substrate requires ensuring machining accuracy in both directions during processing, which is a significant process challenge. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide an optical waveguide display system and a near-eye display device, which can improve the field of view of the system while multiplexing the 0th-order diffraction light, and the difficulty of processing the optical waveguide is relatively low.

[0006] In one aspect, the present invention provides an optical waveguide display system, comprising a waveguide substrate, a one-dimensional coupling grating, a recycling optical component, and an exit pupil expansion optical component. The one-dimensional coupling grating is disposed on a side surface of the waveguide substrate and is used to couple a target image source into the waveguide substrate, generate a first target light beam that can be totally reflected and propagated in a first direction within the waveguide substrate, and generate zero-order diffracted light that is transmitted from the waveguide substrate; the recycling optical component is used to couple the zero-order diffracted light back into the waveguide substrate and generate a second target light beam that can be totally reflected and propagated in a second direction within the waveguide substrate; the exit pupil expansion optical component is disposed on the waveguide substrate and is used to expand the first target light beam and the second target light beam and couple them out of the waveguide substrate in a superimposed manner; wherein the first direction is different from the second direction.

[0007] In addition, the optical waveguide display system according to the present invention may also have the following additional technical features:

[0008] Furthermore, the recycling optical component includes a reflective optical element and a coupling optical element. The reflective optical element is arranged on the other side of the waveguide matrix opposite to the one-dimensional coupling grating, and the coupling optical element is arranged on the waveguide matrix. The reflective optical element is used to multiple reflect the 0th order diffraction light to the coupling optical element, and the coupling optical element is used to modulate the 0th order diffraction light into a second target light beam.

[0009] Furthermore, the coupling optical element is a reflective diffraction grating, the coupling optical element and the one-dimensional coupling grating are both located on the same side of the waveguide substrate, and the area of ​​the coupling optical element does not overlap with the area of ​​the one-dimensional coupling grating.

[0010] Furthermore, the coupling optical element is a transmission diffraction grating, and the coupling optical element and the one-dimensional coupling grating are respectively located on opposite sides of the waveguide substrate, and the area of ​​the coupling optical element does not overlap with the area of ​​the one-dimensional coupling grating.

[0011] Furthermore, the reflective optical element includes a bottom edge and side edges forming an angle β with both ends of the bottom edge, the bottom edge is close to and parallel to the waveguide substrate, the area of ​​the bottom edge covers the area of ​​the one-dimensional coupling grating and the coupling optical element, and the angle β satisfies:

[0012]

[0013] Wherein, n is the refractive index of the reflective optical element.

[0014] Furthermore, the bottom edge is coated with an AR film, and both side edges are coated with an HR film or a metal film.

[0015] Furthermore, the exit pupil expansion optical component includes a first turning optical element, a second turning optical element, and a coupling optical element. The first turning optical element is used to expand the first target light beam and turn it to the first dimension direction of the coupling optical element. The second turning optical element is used to expand the second target light beam and turn it to the second dimension direction of the coupling optical element. The coupling optical element is used to superimpose the light in the first dimension direction and the light in the second dimension direction and couple them out of the waveguide matrix.

[0016] Furthermore, the first turning optical element and the second turning optical element are both one-dimensional diffraction gratings, and the outcoupling optical element is a two-dimensional diffraction grating.

[0017] Furthermore, the angle α1 between the grating line direction of the one-dimensional coupling grating and the straight line where the second direction is located satisfies -45°≤α1≤45°, and the angle α2 between the grating line direction of the coupling optical element and the straight line where the first direction is located satisfies -45°≤α2≤45°.

[0018] On the other hand, the present invention further provides a near-eye display device, comprising a micro-light engine and the aforementioned optical waveguide display system, wherein the micro-light engine is used to generate a target image source.

[0019] The present invention has the following beneficial effects: only one-dimensional diffraction gratings need to be processed and manufactured on the waveguide substrate, and the zero-order diffraction light transmitted through the waveguide substrate is used by a recycling optical component to transmit the target image source information, which can improve the utilization rate of the incident target image source energy. At the same time, because the first target light beam and the second target light beam have independent main propagation paths, when the light beams of the two main paths carry image information with different field of view angles or carry different missing field of view angles of the image, after being expanded and superimposed and coupled by the exit pupil expansion optical component and transmitted to the human eye, the overall field of view angle can be increased and the uniformity of the light intensity distribution can be increased. Compared with the existing technology, there is no need to set strictly aligned one-dimensional diffraction gratings on the upper and lower surfaces of the waveguide substrate, so that the processing complexity of the waveguide substrate is reduced. At the same time, there is no need to set a two-dimensional grating to decompose the target image source into two independently propagating light rays, so that the processing complexity of the waveguide substrate is reduced while the parameters of the one-dimensional grating can be freely adjusted, so that the optical waveguide system has a higher diffraction efficiency, thereby improving the imaging effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of a first side structure of an embodiment of the present invention;

[0021] Figure 2 is a schematic diagram of a second side structure of an embodiment of the present invention;

[0022] Figure 3 A top view of an embodiment of the present invention;

[0023] Figure 4A schematic diagram of the grating line direction of a one-dimensional in-coupling grating in an embodiment of the present invention;

[0024] Figure 5 Schematic diagram of the direction of grating lines of the coupling optical element in an embodiment of the present invention;

[0025] Figure 6 is a schematic structural diagram of a reflective optical element according to an embodiment of the present invention;

[0026] Description of main component symbols:

[0027] Target image source 0, first direction 1, second direction 2, first dimension direction 3, second dimension direction 4, 0th order diffraction light 11, -1st order diffraction light 12, +1st order diffraction light 13, one-dimensional coupling-in grating 21, coupling-in optical element 22, first turning optical element 31, second turning optical element 32, reflecting optical element 40, waveguide matrix 50, outcoupling optical element 60.

[0028] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0029] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate several embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0030] It should be noted that when an element is referred to as being "attached to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only.

[0031] Please refer to Figure 1 and Figure 3, an optical waveguide display system provided by the present invention, the optical waveguide system includes a waveguide substrate 50, a one-dimensional coupling grating 21, a recycling optical component, and an exit pupil expansion optical component. The waveguide substrate 50 serves as a carrier for the one-dimensional coupling grating 21 and is also a medium for light transmission. Therefore, the selection of the material of the waveguide substrate 50 must ensure good diffraction performance while also allowing light with smaller incident angles to be totally reflected. Therefore, a material with a large refractive index is required. In addition, when the thickness of the waveguide substrate 50 is too thick, the optical path of the light undergoing a total reflection within the waveguide substrate 50 is long, resulting in a low light density at the exit pupil and the problem of the images in each field of view not being able to overlap. For this reason, a high-refractive-index wafer with a refractive index of 1.6 to 2.5 is preferably selected as the waveguide substrate 50, and its thickness is controlled to be 0.3 mm to 1.5 mm.

[0032] Exemplarily, a one-dimensional coupling-in grating 21 is disposed on the upper side of the waveguide matrix 50. The one-dimensional coupling-in grating 21 is used to diffract and modulate the target image source 0 on the upper side of the waveguide matrix 50 into 0th-order diffracted light 11 and -1st-order diffracted light 12. That is, the energy of the diffracted light is concentrated in the 0th-order diffracted light 11 and -1st-order diffracted light 12. The 0th-order diffracted light 11 passes through the waveguide matrix 50 and is transmitted out of the lower side thereof. Because the incident angle of the -1st-order diffracted light 12 is greater than or equal to the critical angle for total internal reflection of the waveguide matrix 50, the -1st-order diffracted light 12 undergoes multiple total internal reflections along the first direction 1 within the waveguide matrix 50 at a certain step size. It is understood that a one-dimensional coupling-in grating 21 capable of diffracting and modulating the target image source 0 into 0th-order diffracted light 11 and +1st-order diffracted light 13 (not shown in the drawings) may also be selected.

[0033] The recycling optical component is used to couple the 0th-order diffraction light 11 transmitted from the waveguide matrix 50 back into the waveguide matrix 50, and modulate it into a second target light beam that can be totally reflected and propagated along the second direction 2 in the waveguide matrix 50. The second direction 2 is different from the first direction 1 to form two independent main propagation paths.

[0034] The pupil expansion optical component is provided on the waveguide substrate 50, and is used to expand the -1 order diffracted light 12 and the second target light beam and couple them out of the waveguide substrate 50. For example, the first direction 1 and the second direction 2 are perpendicular to each other, that is, they correspond to Figure 3 The negative direction of the Y axis and the positive direction of the X axis.

[0035] In this embodiment, the 0th-order diffraction light 11 transmitted through the waveguide matrix 50 is used by recycling the optical component to propagate the target image source information, thereby improving the utilization rate of the incident target image source energy. At the same time, since the -1st-order diffraction light 12 and the second target light beam have independent main propagation paths, when the light beams of these two main paths carry image information with different field of view angles or carry different missing field of view angles of the images, after being expanded and superimposed and coupled by the exit pupil expansion optical component and transmitted to the human eye, the overall field of view angle can be increased and the uniformity of the light intensity distribution can be increased.

[0036] In some optional embodiments, the one-dimensional coupling-in grating 21 can be a surface relief grating or a volume holographic grating. To concentrate the energy of the diffracted light in the 0th-order diffracted light 11 and the -1st-order diffracted light 12, thereby reducing the generation of diffracted light of other diffraction orders and avoiding the generation of stray light, a tilted grating or a blazed grating in the surface relief grating is preferably used. Furthermore, according to the grating diffraction formula, in order to ensure that the -1st-order diffracted light can satisfy the total internal reflection condition of the waveguide substrate 50, the grating period of the tilted grating or the blazed grating is smaller than the wavelength of the target image source, that is, the tilted grating or the blazed grating is a sub-wavelength grating.

[0037] For sub-wavelength surface relief gratings, the groove type of the grating has a significant impact on the diffraction efficiency. The groove types commonly used in the surface relief grating process are rectangular gratings, sawtooth gratings and tilted gratings. The symmetrical rectangular grating will have half of the diffracted light not propagating towards the exit pupil, wasting half of the energy. The sawtooth grating, also called the blazed grating, due to its asymmetric design, can be optimized to eliminate the diffracted light that is not towards the exit pupil, thereby maximizing the efficiency of the diffracted light towards the exit pupil. Furthermore, compared to the sawtooth grating, the tilted grating has more design freedom and can obtain greater diffraction efficiency, but it has higher requirements on the surface relief grating processing technology. Therefore, the functions in this example can be achieved by using either the tilted grating or the blazed grating in the surface relief grating.

[0038] In some optional embodiments, such as Figure 1 、 3 As shown, the recycling optical component includes a reflective optical element 40 and a coupling optical element 22. The reflective optical element 40 is arranged on the other side of the waveguide matrix 50 opposite to the one-dimensional coupling grating 21, that is, on the side of the lower side of the waveguide matrix 50. The coupling optical element 22 is arranged on the waveguide matrix 50. When the 0th order diffraction light 11 is transmitted from the lower side of the waveguide matrix 50, it re-enters the waveguide matrix 50 after multiple reflections by the reflective optical element 40. Thereafter, the coupling optical element 22 modulates the 0th order diffraction light 11 into a second target light beam, which can be totally reflected and propagated along the second direction 2 in the waveguide matrix 50.

[0039] In some optional embodiments, such as Figure 6 As shown, the reflective optical element 40 is an isosceles prism, which includes a base S1, side S2 and side S3, both of which form an angle β with both ends of the base S1. The base S1 is close to the waveguide matrix 50 and is parallel to the waveguide matrix 50. To ensure that the isosceles prism can fully receive the 0th-order diffracted light 11 transmitted from the lower side of the waveguide matrix 50, and that the 0th-order diffracted light 11 that is multiply reflected by the isosceles prism can be fully received by the coupling-in optical element 22, the area of ​​the base S1 covers the area of ​​the one-dimensional coupling-in grating 21 and the coupling-in optical element 22. In addition, in order for the isosceles prism to effectively reflect the 0th-order diffracted light 11, the angle β needs to satisfy the following formula:

[0040]

[0041] Wherein, n is the refractive index of the reflective optical element 40 , and preferably, the value range of n is 1.5 to 2.5.

[0042] In this embodiment, the 0th-order diffraction light 11 coupled out from the lower side of the waveguide matrix 50 is vertically incident from the bottom edge S1 (Z-axis direction in the figure) into the isosceles prism, reflected by the side edge S3 and propagated to the bottom edge S1, then reflected by the bottom edge S1 and propagated to the side edge S2, and finally vertically emitted from the bottom edge S1 and enters the waveguide matrix 50 to be received by the coupled-in optical element 22.

[0043] In some optional embodiments, an anti-reflection film (AR film) is coated on the bottom edge S1, and the side edges S2 and S3 are coated with a high-reflection film (HR film) or a metal film. Optionally, the metal film may be made of gold, silver, aluminum, or the like. In this embodiment, by coating the bottom edge S1 with an anti-reflection film, the reflection can be reduced, allowing the 0th-order diffracted light 11 to be more completely transmitted into the isosceles prism, and allowing the 0th-order diffracted light 11 emitted vertically from the bottom edge S1 to be more completely transmitted out of the isosceles prism, thereby reducing the energy loss of the light beam. In addition, by coating the side edges S2 and S3 with a high-reflection film (HR film) or a metal film, the 0th-order diffracted light 11 can be effectively reflected, thereby improving the reflection efficiency of the isosceles prism. At the same time, when some light does not meet the reflection condition of the β angle, it can still be reflected by the high-reflection film (HR film) or the metal film.

[0044] In some optional embodiments, such as Figure 1 、 3As shown, the coupling-in optical element 22 is a reflective diffraction grating. Both the coupling-in optical element 22 and the one-dimensional coupling-in grating 21 are located on the upper side of the waveguide substrate 50. To prevent interference between the one-dimensional coupling-in grating 21 and the coupling-in optical element 22, the area of ​​the coupling-in optical element 22 does not overlap with the area of ​​the one-dimensional coupling-in grating 21. For example, the center-to-center distance D1 between the one-dimensional coupling grating 21 and the coupling-in optical element 22 satisfies 12 mm ≥ D1 ≥ 4 mm.

[0045] In this embodiment, when the 0th-order diffracted light 11 is transmitted from the lower side of the waveguide matrix 50, it is re-transmitted into the waveguide matrix 50 after multiple reflections by the reflective optical element 40. It is then received by the reflective diffraction grating, which diffracts the 0th-order diffracted light 11 into a second target light beam. Exemplarily, the second target light beam is the +1st-order diffracted light 13 diffracted by the reflective diffraction grating. The +1st-order diffracted light 13 propagates in the waveguide matrix 50 by total reflection along the second direction 2. Alternatively, the reflective diffraction grating can be a surface relief grating or a volume holographic grating. To concentrate the energy of the diffracted light in the +1st-order diffracted light 13, reduce the generation of diffracted light of other diffraction orders, and avoid stray light, a tilted grating or a blazed grating in the surface relief grating is preferably used. In addition, according to the grating diffraction formula, in order to satisfy the total reflection condition of the waveguide matrix 50 for the +1-order diffracted light 13, the grating period of the tilted grating or the blazed grating is smaller than the wavelength of the target image source 0, that is, the tilted grating or the blazed grating is a sub-wavelength grating.

[0046] In some optional embodiments, such as Figure 2 、 3 As shown, the coupling-in optical element 22 is a transmissive diffraction grating located on the bottom side of the waveguide substrate 50. To prevent interference between the one-dimensional coupling-in grating 21 and the coupling-in optical element 22, the area of ​​the coupling-in optical element 22 does not overlap with the area of ​​the one-dimensional coupling-in grating 21. For example, the center-to-center distance D1 between the one-dimensional coupling grating 21 and the coupling-in optical element 22 satisfies 12 mm ≥ D1 ≥ 4 mm.

[0047] In this embodiment, when the 0th-order diffracted light 11 is transmitted from the lower side of the waveguide matrix 50, it is re-transmitted into the waveguide matrix 50 after multiple reflections by the reflective optical element 40. It is then received by the transmissive diffraction grating, which diffracts the 0th-order diffracted light 11 into a second target light beam. Exemplarily, the second target light beam is the +1st-order diffracted light 13 diffracted by the reflective diffraction grating. The +1st-order diffracted light 13 propagates in the waveguide matrix 50 by total internal reflection along the second direction 2. Alternatively, the reflective diffraction grating may be a surface relief grating or a volume holographic grating. To concentrate the energy of the diffracted light in the +1st-order diffracted light 13, reduce the generation of diffracted light of other diffraction orders, and avoid stray light, a tilted grating or a blazed grating in the surface relief grating is preferably used. In addition, according to the grating diffraction formula, in order to satisfy the total reflection condition of the waveguide matrix 50 for the +1-order diffracted light 13, the grating period of the tilted grating or the blazed grating is smaller than the wavelength of the target image source 0, that is, the tilted grating or the blazed grating is a sub-wavelength grating.

[0048] In some optional embodiments, such as Figure 3 As shown, the exit pupil expansion optical assembly includes a first turning optical element 31, a second turning optical element 32, and an outcoupling optical element 60. The first turning optical element 31 is used to expand the -1 order diffracted light 12 and turn it to the first dimension 3 of the outcoupling optical element 60. The second turning optical element 32 is used to expand the second target light beam and turn it to the second dimension 4 of the outcoupling optical element 60. The outcoupling optical element 60 is used to superimpose the light in the first dimension 3 and the light in the second dimension 4 and couple them out of the waveguide matrix 50, thereby achieving two-dimensional exit pupil expansion. Preferably, the first turning optical element 31 and the second turning optical element 32 are both one-dimensional diffraction gratings, and the outcoupling optical element 60 is a two-dimensional diffraction grating. In this embodiment, since the -1 order diffraction light 12 and the second target light beam have independent main propagation paths respectively, when the light beams of these two main paths carry image information with different field of view angles or carry different missing field of view angles of the image, the -1 order diffraction light 12 enters the outcoupling optical element 60 after being turned and expanded by the first turning optical element 31, and expands in the first dimension direction 3. The second target light beam enters the outcoupling optical element 60 after being turned and expanded by the second turning optical element 32, and expands in the second dimension direction 4. When the -1 order diffraction light 12 and the second target light beam at the corresponding position of the outcoupling optical element 60 are superimposed and coupled to the human eye, the field of view of the image observed by the human eye is increased, and the image light intensity distribution is uniform.

[0049] In some optional embodiments, such as Figure 3As shown, it is assumed that the periods of the one-dimensional coupling-in grating 21, coupling-in optical element 22, first turning unit 31, and second turning unit 32, which are one-dimensional diffraction gratings, are P21, P22, P31, and P32, respectively, and the corresponding grating vectors are K11, K21, K12, and K22, respectively. The periods of the two-dimensional directions of the coupling-out optical element 60, which are two-dimensional diffraction gratings, are P61 and P62, respectively, and the corresponding grating vectors are K13 and K23, respectively. To ensure that the phase changes of the one-dimensional coupling-in grating 21, first turning unit 31, and coupling-out optical element 60 in the first main propagation path are matched, so that the target image source 0 is effectively coupled into the waveguide substrate 50 and then coupled out without dispersion, thereby improving the visual imaging effect, the vector sum of K11, K12, and K13 is set to zero. Similarly, for the first main propagation path, the vector sum of K21, K22, and K23 is set to zero. In addition, when the diffraction gratings are all processed on the same side of the waveguide matrix 50, the processing difficulty can be reduced and the matching accuracy can be improved compared to the layout distributed on both sides of the waveguide matrix 50. Therefore, it is preferred that the one-dimensional coupling grating 21, the coupling optical element 22, the first turning unit 31, the second turning unit 32, and the coupling-out optical element 60 are all arranged on the same surface side of the waveguide matrix 50.

[0050] In some optional embodiments, such as Figure 3 、 4 As shown, in order to improve the diffraction efficiency of the one-dimensional coupling grating 21 and modulate the diffraction of the target image source 0 on the upper side of the waveguide substrate 50 into only the 0th order diffraction light 11 and the -1st order diffraction light 12, and to increase the energy proportion of the -1st order diffraction light 12, the angle α1 between the grating line direction of the one-dimensional coupling grating 21 and the X-axis is set to satisfy -45°≤α1≤45°. Similarly, as Figure 3 、 5 As shown, in order to make the coupling optical element 22 diffract and modulate the 0th order diffraction light 11 into only +1st order diffraction light 13 and improve the diffraction efficiency of this order diffraction light, the angle α2 between the grating line direction of the coupling optical element 22 and the Y axis is set to satisfy -45°≤α2≤45°.

[0051] On the other hand, the present invention also provides a near-eye display device, such as Figure 1 and Figure 3 As shown, the near-eye display device includes a micro light engine 10 and the aforementioned optical waveguide display system. The micro light engine 10 is used to generate a target image source 0. The target image source 0 is vertically incident (Z-axis direction in the figure) to a one-dimensional coupling grating 21. Optionally, the micro light engine can be a Micro-LED optical engine, a DLP optical engine, an LCOS optical engine or an LBS optical engine.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0053] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0054] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An optical waveguide display system, characterized in that: The optical waveguide display system comprises: Waveguide substrate; A one-dimensional coupling grating is disposed on one side of the waveguide matrix, and is used to couple a target image source into the waveguide matrix, generate a first target light beam that can be totally reflected and propagated in a first direction in the waveguide matrix, and generate a 0th-order diffracted light transmitted from the waveguide matrix; A recycling optical component, used for coupling the 0th order diffracted light back into the waveguide matrix and generating a second target light beam capable of being totally reflected and propagated in the waveguide matrix along a second direction, the recycling optical component comprising a reflecting optical element and a coupling optical element, the reflecting optical element being arranged on the other side of the waveguide matrix opposite to the one-dimensional coupling grating, the coupling optical element being arranged on the waveguide matrix, the reflecting optical element being used for multiple reflections of the 0th order diffracted light onto the coupling optical element, and the coupling optical element being used for modulating the 0th order diffracted light into the second target light beam; An exit pupil expansion optical component is provided on the waveguide substrate, and is used to expand the first target light beam and the second target light beam and couple them out of the waveguide substrate in a superimposed manner; The first direction is different from the second direction.

2. The optical waveguide display system according to claim 1, characterized in that: The coupling optical element is a reflective diffraction grating. The coupling optical element and the one-dimensional coupling grating are both located on the same side of the waveguide substrate, and the area of ​​the coupling optical element does not overlap with the area of ​​the one-dimensional coupling grating.

3. The optical waveguide display system according to claim 1, characterized in that: The coupling optical element is a transmission diffraction grating. The coupling optical element and the one-dimensional coupling grating are respectively located on opposite sides of the waveguide substrate, and the area of ​​the coupling optical element does not overlap with the area of ​​the one-dimensional coupling grating.

4. The optical waveguide display system according to any one of claims 1 to 3, characterized in that: The reflective optical element comprises a bottom edge and side edges which form an angle β with both ends of the bottom edge, the bottom edge is close to and parallel to the waveguide substrate, the area of ​​the bottom edge covers the area of ​​the one-dimensional coupling grating and the coupling optical element, and the angle β satisfies: Wherein, n is the refractive index of the reflective optical element.

5. The optical waveguide display system according to claim 4, characterized in that: The bottom edge is coated with an AR film, and the two side edges are coated with an HR film or a metal film.

6. The optical waveguide display system according to claim 1, characterized in that: The exit pupil expansion optical component includes a first turning optical element, a second turning optical element, and a coupling optical element. The first turning optical element is used to expand the first target light beam and turn it to the first dimension direction of the coupling optical element. The second turning optical element is used to expand the second target light beam and turn it to the second dimension direction of the coupling optical element. The coupling optical element is used to superimpose the light in the first dimension direction and the light in the second dimension direction and couple them out of the waveguide matrix.

7. The optical waveguide display system according to claim 6, characterized in that: The first turning optical element and the second turning optical element are both one-dimensional diffraction gratings, and the outcoupling optical element is a two-dimensional diffraction grating.

8. The optical waveguide display system according to claim 2 or 3, characterized in that: The angle α1 between the grating line direction of the one-dimensional coupling grating and the straight line where the second direction is located satisfies -45°≤α1≤45°, and the angle α2 between the grating line direction of the coupling optical element and the straight line where the first direction is located satisfies -45°≤α2≤45°.

9. A near-eye display device, characterized in that: The optical waveguide display system comprises a micro light engine and the optical waveguide display system according to any one of claims 1 to 8, wherein the micro light engine is used to generate the target image source.

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