A binocular diffractive waveguide and near-eye display device

Abstract

This application provides a binocular diffractive waveguide, comprising: a monolithic waveguide substrate, the monolithic waveguide substrate having a left-eye optical path region and a right-eye optical path region, the left-eye optical path region including a left-eye coupling region and a left-eye coupling region, and the right-eye optical path region including a right-eye coupling region and a right-eye coupling region; both the left-eye coupling region and the right-eye coupling region are located close to the centerline of the monolithic waveguide substrate; the waveguide outer contour design of the right-eye optical path region is such that: after image light is diffracted by the grating structure in the left-eye coupling region, the non-working order of light rays heading towards the right-eye optical path region does not enter the right-eye optical path region; and the waveguide outer contour design of the left-eye optical path region is such that: after image light is diffracted by the grating structure in the right-eye coupling region, the non-working order of light rays heading towards the left-eye optical path region does not enter the left-eye optical path region. This application can achieve true 3D display, while being compact in structure and comfortable to wear, suppressing binocular crosstalk.

Description

Technical Field

[0001] This application relates to the field of augmented reality display technology, and more particularly to a binocular diffractive waveguide and near-eye display device. Background Technology

[0002] Augmented reality is a technology that blends the real world with virtual information. Augmented reality display systems typically include micro-projectors and optical displays. The micro-projectors provide virtual display content for the augmented reality display system, which is then projected onto the viewer's eyes through the optical displays. The optical displays are usually transparent optical components, so that users can also see the real world through the optical displays at the same time.

[0003] To reduce costs, existing consumer AR glasses use a single-optical-engine binocular technology solution. However, the fixed optical path provided by this technology is difficult to adapt to different interpupillary distances, which can easily lead to ghosting and eye fatigue. Moreover, it does not support true 3D display. The optical performance is limited by the shared optical path design of the single-optical-engine binocular structure, which has gradually become a technical bottleneck restricting the development of consumer AR glasses towards high performance, comfort, and true 3D. Summary of the Invention

[0004] This application provides a binocular diffractive waveguide that achieves true 3D display through a monolithic waveguide dual-coupled center-mounted design. It features a compact structure, comfortable wear, and optimized optical path and contour to avoid crosstalk between the left and right eyes, thereby improving image quality.

[0005] A binocular diffractive waveguide includes: a monolithic waveguide substrate having a left-eye optical path region and a right-eye optical path region; the left-eye optical path region includes a left-eye coupling region and a left-eye coupling region; the right-eye optical path region includes a right-eye coupling region and a right-eye coupling region; both the left-eye coupling region and the right-eye coupling region are located close to the centerline of the monolithic waveguide substrate; the waveguide outer contour design of the right-eye optical path region is such that: after image light is diffracted by the grating structure in the left-eye coupling region, the non-working order of the light rays heading towards the right-eye optical path region does not enter the right-eye optical path region; the waveguide outer contour design of the left-eye optical path region is such that: after image light is diffracted by the grating structure in the right-eye coupling region, the non-working order of the light rays heading towards the left-eye optical path region does not enter the left-eye optical path region.

[0006] In practice, the monolithic waveguide substrate is bilaterally symmetrical and has local asymmetry above the midline; the center of the left eye coupling region and the center of the right eye coupling region are mirror symmetrical about the midline, and the size of the left eye coupling region is different from that of the right eye coupling region.

[0007] Implementably, the size of the left eye coupling region satisfy:

[0008]

[0009] The size of the right eye coupling region satisfy:

[0010]

[0011] Where L is the distance from the exit pupil of the projection optical engine to the monolithic waveguide substrate. The field of view of the left eye in the binocular diffractive waveguide. The field of view of the right eye in the binocular diffractive waveguide. The exit pupil diameter of the projection optical engine. The thickness of the monolithic waveguide substrate is given. The diffraction angle of the image light rays after passing through the left eye coupling region. The diffraction angle of the image light rays after passing through the right eye coupling region. The value range is 0.3–1 mm.

[0012] In an implementable manner, a grating structure is disposed on an entire area of ​​the surface of the monolithic waveguide substrate. The center position of the left eye optical path area corresponds to the center of the left eye pupil, and the center position of the right eye optical path area corresponds to the center of the right eye pupil. The lateral dimension of the left eye optical path area and / or the right eye optical path area is 35-40 mm, and the longitudinal dimension of the left eye optical path area and / or the right eye optical path area is 35-40 mm. The lateral distance between the center position of the left eye coupling area and the center position of the left eye optical path area is 12-16 mm, and the longitudinal distance is 4-8 mm. The lateral distance between the center position of the right eye coupling area and the center position of the right eye optical path area is 12-16 mm, and the longitudinal distance is 4-8 mm.

[0013] In an implementable manner, a grating structure is disposed in a local area on the surface of the monolithic waveguide substrate, the local area including at least the left eye coupling region, the left eye coupling region, the right eye coupling region, and the right eye coupling region; wherein, the distance between the center position of the left eye coupling region and the center position of the left eye coupling region is 25-32 mm in the lateral direction and 5-15 mm in the longitudinal direction; the distance between the center position of the right eye coupling region and the center position of the right eye coupling region is 25-32 mm in the lateral direction and 5-15 mm in the longitudinal direction.

[0014] In practice, the binocular connection of the monolithic waveguide substrate is a deep concave arc-shaped structure. The bottom of the groove of the deep concave arc-shaped structure is not higher than the higher of the center position of the left eye coupling region and the center position of the right eye coupling region, and the bottom of the groove of the deep concave arc-shaped structure is not lower than the lower of the lowest position of the left eye coupling region and the lowest position of the right eye coupling region.

[0015] Implementably, a one-dimensional left-eye coupling grating is provided within the left-eye coupling region, and the unit vector of the direction of the one-dimensional left-eye coupling grating is... , The grating orientation angle of the one-dimensional left-coupled grating; after the image light rays are incident on the one-dimensional left-coupled grating and undergo diffraction, the +1 order is the working order, and the transmission direction of the -1 order should satisfy the following with respect to the waveguide outer contour of the right eye optical path region:

[0016]

[0017]

[0018]

[0019] in, The size of the left eye coupling region. The coordinates of the center position of the left eye insertion region are given. The direction of incidence of image light rays into the left eye coupling region. The grating period of the one-dimensional left-coupled grating is... The refractive index of the monolithic waveguide substrate is given. The operating wavelength of the left eye optical path region is [not specified]. Let be the equation of the straight line containing the -1st order transmission direction of the left eye optical path region. The equation of the waveguide outer contour of the right eye optical path region is given.

[0020] In practice, the wavebands of the image light transmitted in the left eye optical path area and the right eye optical path area are different.

[0021] In practice, the image light transmitted in one of the optical paths of the left eye optical path area and the right eye optical path area is in the red-green band, and the image light transmitted in the other optical path area is in the blue-green band; or, the image light transmitted in one of the optical paths of the left eye optical path area and the right eye optical path area is in the full band, and the image light transmitted in the other optical path area is in the green band.

[0022] A near-eye display device includes a left-eye optical engine, a right-eye optical engine, and the aforementioned binocular diffractive waveguide, wherein the left-eye optical engine corresponds to the left-eye optical path area and is used to independently control the opening and closing of the left-eye optical path; the right-eye optical engine corresponds to the right-eye optical path area and is used to independently control the opening and closing of the right-eye optical path.

[0023] The binocular diffractive waveguide provided in this application adopts a monolithic waveguide substrate, integrating the left and right eye optical path areas onto the same substrate. This facilitates the realization of a monolithic binocular integrated structure, simplifies the assembly process, and improves system stability. Furthermore, the coupling areas for both eyes are concentrated in the central region of the substrate, allowing the optical engine to be positioned on the bridge of the nose for direct forward coupling. This eliminates the need for lateral light transmission or complex steering structures, resulting in a more compact and integrated overall optical layout, shorter transmission path, and reduced path loss. Simultaneously, this structure frees up mounting space in the temple area, providing greater layout leeway for other functional components such as batteries, motherboards, and sensors. This optimizes the overall weight distribution, significantly improving wearing comfort and stability. Moreover, the optical engine's location on the bridge of the nose offers advantages over its location on the temple side in terms of energy propagation loss.

[0024] Furthermore, this application specifically optimizes the outer contour of the waveguide based on the structural characteristics of a single substrate coupled to the center. By adjusting the propagation path and exit boundary of the diffraction order, non-working order rays generated in the left eye optical path area cannot enter the right eye optical path area, and non-working order rays generated in the right eye optical path area cannot enter the left eye optical path area. This blocks optical crosstalk between the left and right eyes from the propagation path, further improving the contrast, clarity and visual purity of binocular imaging. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A schematic diagram of a binocular diffractive waveguide provided in an embodiment of this application;

[0027] Figure 2 A schematic diagram of another binocular diffractive waveguide provided in an embodiment of this application;

[0028] Figure 3 A schematic diagram of another binocular diffractive waveguide provided in an embodiment of this application;

[0029] Figure 4 A schematic diagram of another binocular diffractive waveguide provided in an embodiment of this application;

[0030] Figure label:

[0031] 110, Left eye optical path area; 111, Left eye coupling region; 112, Left eye coupling region;

[0032] 120, right eye optical path area; 121, right eye coupling region; 122, right eye coupling region. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0035] This application provides a binocular diffractive waveguide, which includes a monolithic waveguide substrate having a left-eye optical path region and a right-eye optical path region. The left-eye optical path region includes a left-eye coupling region and a left-eye coupling out region, and the right-eye optical path region includes a right-eye coupling in region and a right-eye coupling out region. Both the left-eye coupling in region and the right-eye coupling in region are located close to the centerline of the monolithic waveguide substrate. The waveguide outer contour design of the right-eye optical path region ensures that the non-working order of image light rays diffracted by the grating structure in the left-eye coupling region does not enter the right-eye optical path region. The waveguide outer contour design of the left-eye optical path region ensures that the non-working order of image light rays diffracted by the grating structure in the right-eye coupling region does not enter the left-eye optical path region.

[0036] The monolithic waveguide substrate is an optical waveguide substrate formed from a single continuous transparent optical material. Both the left and right eye optical pathway regions are integrated on the monolithic waveguide substrate, sharing the same optical substrate, rather than being a separate assembly structure formed by splicing, bonding, or assembling the left and right eye waveguides. For example, the transparent optical materials forming the monolithic waveguide substrate include, but are not limited to, glass, resin, and silicon carbide.

[0037] Specifically, the centerline of the monolithic waveguide substrate divides it into two parts: a left-eye optical path region and a right-eye optical path region. Typically, the waveguide shapes of the left and right eye optical path regions are symmetrically arranged about the centerline of the monolithic waveguide substrate. In some embodiments, when the left and right eye optical path regions correspond to different color channels, an asymmetrical coupling implementation can be selected. In this case, there may be local asymmetry above the centerline of the monolithic waveguide substrate; that is, the monolithic waveguide substrate is bilaterally symmetrical about the centerline, except for a local area above the centerline.

[0038] In practice, the wavelengths of the image light transmitted in the left and right eye optical paths can be the same. This design is generally suitable for conventional augmented reality display applications, such as monochrome displays and binocular synchronized image displays. It can effectively simplify the structure, reduce design and manufacturing costs, and improve the versatility and practicality of the product. For example, both the left and right eye optical paths transmit green light wavelengths for information prompts such as navigation arrows and message notifications; both the left and right eye optical paths transmit the full wavelength for full-color display scenarios such as audio-visual entertainment, virtual interaction, reality fusion, and industrial simulation.

[0039] In practice, the wavelengths of the image light transmitted in the left and right eye optical paths can also be different. This design can be adapted to special augmented reality display applications, such as binocular color separation display and stereoscopic augmented display, further expanding the functional boundaries of AR glasses. For example, the left eye optical path can be set to transmit red and green wavelengths, and the right eye optical path can transmit blue and green wavelengths, enabling binocular color separation display and achieving richer color representation through binocular color separation superposition. Alternatively, the left eye optical path can be set to transmit the full wavelength, and the right eye optical path can transmit the green wavelength, achieving a better display effect through supplementary superposition.

[0040] When the wavebands of the image light transmitted in the left and right eye optical paths are different, the left and right eyes can transmit image light in different local wavebands respectively, for example, red-green in the left eye and blue-green in the right eye. Full-color imaging is achieved by relying on human visual fusion, and the design difficulty of full-color waveguide is simplified by using a beam splitting structure. Alternatively, one eye can be monochrome and the other full-color, for example, full-color in the left eye and single green in the right eye. The full-color image in the left eye is superimposed on the pure green light substrate in the right eye by relying on the human visual binocular fusion mechanism to synthesize a final display effect with high transparency, high brightness and low dispersion.

[0041] Specifically, taking the left-eye optical path region as an example, the left-eye optical path region includes at least a left-eye coupling region and a left-eye coupling region. In some embodiments, it also includes a left-eye turning region and / or other functional regions. After light enters the left-eye coupling region, it is diffracted by the grating structure within the left-eye coupling region, resulting in multiple orders. Among these, the orders that propagate to the left-eye coupling region and couple out are the working orders, while the other orders are non-working orders. These non-working orders cannot be effectively utilized mainly because their propagation direction is away from the direction of the left-eye coupling region. Based on this, the waveguide outer contour design of the right-eye optical path region ensures that non-working orders that propagate towards the direction of the right-eye optical path region after image light diffracts through the grating structure within the left-eye coupling region do not enter the right-eye optical path region. It can be understood that there may be non-working orders that exit the waveguide substrate from the side and propagate towards the direction of the right-eye optical path region. In this case, it can be exemplarily implemented that the waveguide outer contour of the right-eye optical path region is not on the propagation path of the non-working order. Furthermore, non-working light rays propagate within the waveguide substrate towards the right eye optical path region. Based on this, this application also designs the connecting region along the centerline of the monolithic waveguide substrate to ensure that light rays propagating within the left eye optical path region almost do not enter the right eye optical path region, achieving optical isolation and physical separation from the left eye optical path region to the right eye optical path region. The same principle applies to the right eye optical path region, thereby achieving optical isolation and physical separation between the left and right eye optical path regions and suppressing optical crosstalk between the two eyes. The design of the connecting region along the centerline of the monolithic waveguide substrate includes, but is not limited to, substrate hollowing, blackening, and diffraction efficiency suppression.

[0042] It is understandable that the size of the coupling region should not be too large or too small. If the coupling region is too small, the diffraction spot will be too small, which may lead to problems such as pupil splitting. If the coupling region is too large, the incident light will diffract multiple times in the coupling region, resulting in diffraction loss and the formation of ghost images. Based on this, and since the diffraction angles of light of different wavelengths are different, the size of the coupling region can also be different to achieve better results.

[0043] In some embodiments, the image light transmitted in the left and right eye optical path regions has different wavelengths. The size of the coupling region within the left and right eye optical path regions can be designed differently for the wavelengths of light that need to be coupled in, in order to adapt to the diffraction characteristics and transmission requirements of different wavelengths of light, ensuring that each wavelength of light achieves efficient coupling and low-loss transmission within its corresponding optical path region. For example, considering the characteristics of red light having a larger diffraction angle, followed by green light, and then blue light having the smallest, the size of the coupling region for transmitting red and green wavelengths is relatively large, while the size of the coupling region for transmitting blue and green wavelengths is relatively small; the size of the coupling region for transmitting the entire wavelength band is relatively large, while the size of the coupling region for transmitting the green wavelength band is relatively small.

[0044] In practice, the monolithic waveguide substrate is bilaterally symmetrical, with a local asymmetry above the midline; the centers of the left and right eye coupling regions are mirror-symmetrical about the midline, and the sizes of the left and right eye coupling regions differ. It is understood that, typically, to match the physiological structure of the human eye and binocular vision habits, the left and right eye regions of the waveguide are symmetrically set, i.e., the centers of the left and right eye coupling regions are mirror-symmetrical about the midline. The local asymmetry above the midline here stems from the difference in size between the left and right eye coupling regions; the structural design of the waveguide outer contour is related to the propagation coverage of non-working orders within the waveguide, and the propagation coverage of non-working orders is directly affected by the coupling region size parameters. When the sizes of the left and right eye coupling regions differ, the waveguide outer contour of the right eye optical path region can be designed asymmetrically with respect to the left eye optical path region.

[0045] Implementably, the size of the left eye coupling region satisfy:

[0046]

[0047] Size of the right eye insertion region satisfy:

[0048]

[0049] Where L is the distance from the exit pupil of the projection optical engine to the monolithic waveguide substrate. This represents the field of view of the left eye in a binocular diffractive waveguide. This is the field of view for the right eye in a binocular diffractive waveguide. and They can be the same or different. The exit pupil diameter of the projection optical engine. The thickness of the monolithic waveguide substrate, The angle of diffraction of the image light rays after they enter the left eye coupling region. The angle of diffraction of the image light rays after passing through the right eye coupling region. The value range is 0.3–1 mm.

[0050] For example, see reference. Figure 1 The figure illustrates a schematic diagram of a binocular diffractive waveguide in one embodiment. As shown, a left-eye optical path region 110 and a right-eye optical path region 120 are divided on a monolithic waveguide substrate. The left-eye optical path region 110 includes a left-eye coupling region 111, and the right-eye optical path region 120 includes a right-eye coupling region 121. For example, the left-eye optical path region 110 transmits red-green bands, and the right-eye optical path region 120 transmits blue-green bands. Therefore, the size of the left-eye coupling region 111 is larger than the size of the right-eye coupling region 121, and there is a local asymmetry in the outer contours of the waveguides of the left and right eye optical paths above the midline.

[0051] Of course, in some embodiments, when the coupling region sizes in the left and right eye optical path regions are different, the waveguide outer contours of the right and left eye optical path regions can also be designed symmetrically to meet the requirement of avoiding crosstalk. For example, see reference. Figure 2 The figure illustrates a schematic diagram of a binocular diffractive waveguide in one embodiment. As shown, a left-eye optical path region 110 and a right-eye optical path region 120 are divided on a monolithic waveguide substrate. The left-eye optical path region 110 includes a left-eye coupling region 111, and the right-eye optical path region 120 includes a right-eye coupling region 121. The left-eye optical path region 110 transmits red-green wavelengths, and the right-eye optical path region 120 transmits blue-green wavelengths. The size of the left-eye coupling region 111 is larger than the size of the right-eye coupling region 121. The outer contours of the waveguides of the left and right-eye optical paths are symmetrical about the midline.

[0052] Of course, in some embodiments, when the wavelengths of the image light transmitted in the left eye optical path area and the right eye optical path area are different, the coupling region sizes in the left eye optical path area and the right eye optical path area can also be the same.

[0053] In some embodiments, when planning the coupling region on the surface of a monolithic waveguide substrate, a grating structure can be set throughout the entire region, i.e., the entire region is a coupling region. This integrates the coupling, pupil expansion, and coupling of image light, reducing manufacturing complexity and cost, while expanding the visible area and improving brightness uniformity. Alternatively, the grating structure can be set only in specific areas, such as the central areas of the left and right eye optical paths directly facing the pupil. This reduces the grating area, directly reducing the chance of light scattering on unexpected paths, thereby improving image contrast and reducing background noise. Furthermore, placing the coupling region in the center of the field of vision ensures that the user sees the virtual image when looking directly ahead, conforming to natural visual habits. The specific planning of the coupling region can be selected according to the actual needs of the scenario.

[0054] In an implementable manner, a grating structure is disposed on the entire surface of a monolithic waveguide substrate. The center of the left eye optical path area corresponds to the center of the left eye pupil, and the center of the right eye optical path area corresponds to the center of the right eye pupil. The lateral dimension of the left eye optical path area and / or the right eye optical path area ranges from 35 to 40 mm, and the longitudinal dimension of the left eye optical path area and / or the right eye optical path area ranges from 35 to 40 mm. The lateral distance between the center of the left eye coupling area and the center of the left eye optical path area ranges from 12 to 16 mm, and the longitudinal distance ranges from 4 to 8 mm. The lateral distance between the center of the right eye coupling area and the center of the right eye optical path area ranges from 12 to 16 mm, and the longitudinal distance ranges from 4 to 8 mm.

[0055] In this design, a grating structure is integrally formed over a whole area on the surface of the monolithic waveguide substrate, continuously covering the effective display surface of the waveguide substrate. The specific form of this integrated grating structure can be flexibly configured; it can be a single, monolithic two-dimensional grating, or it can be composed of multiple sets of two-dimensional gratings of different specifications spliced ​​together. It can also employ a structure of multiple sets of one-dimensional gratings of different specifications spliced ​​together, or a combination of multiple sets of two-dimensional gratings and one-dimensional gratings of different specifications spliced ​​together.

[0056] Specifically, the coupling region, as the exit point for light rays transmitted within the waveguide to reach the human eye, must be precisely positioned to match the position of the human pupil, ensuring that the coupled light rays can efficiently enter the eye to form a clear field of vision. In this embodiment, the entire surface area of ​​the monolithic waveguide substrate is integrally covered with a grating structure. Taking into account the time and cost of grating fabrication and the energy loss during light transmission within the waveguide, the dimensions of the left and right eye optical path areas are uniformly defined: the lateral and longitudinal dimensions of both the left and right eye optical path areas are 35-40 mm.

[0057] Based on this, the center of the left eye optical path area corresponds to the center of the left pupil, and the center of the right eye optical path area corresponds to the center of the right pupil. Simultaneously, the relative positions of the coupling area and the corresponding optical path area are optimized: the lateral spacing between the center of the left eye coupling area and the center of the left eye optical path area is controlled at 12-16 mm, and the vertical spacing is controlled at 4-8 mm; the same lateral and vertical distance ranges are followed between the center of the right eye coupling area and the center of the right eye optical path area. This positional architecture design effectively shortens the light transmission path from the coupling area to the eye point, thereby significantly reducing energy loss during light transmission within the waveguide and improving overall optical transmission efficiency.

[0058] For example, refer to Figure 3 The figure illustrates a schematic diagram of a binocular diffractive waveguide in one embodiment. As can be seen, a left-eye optical path region 110 and a right-eye optical path region 120 are divided on a monolithic waveguide substrate. A grating structure is integrally formed on the surface of the monolithic waveguide substrate. The entire left-eye optical path region 110 serves as the left-eye coupling-out region 112, and the position of the left-eye coupling-in region 111 is determined within this grating structure. Similarly, the entire right-eye optical path region 120 serves as the right-eye coupling-out region 122, and the position of the right-eye coupling-in region 121 is determined within this grating structure.

[0059] In some embodiments, after planning the region for manipulating image rays to image on the surface of a monolithic waveguide substrate, a grating structure can be set only within this region. This is a common practice for diffractive waveguides, balancing performance, appearance, and cost. The region for manipulating image rays to image includes the left-eye coupling region, left-eye coupling region, right-eye coupling region, and right-eye coupling region. Furthermore, after other areas of the monolithic waveguide substrate surface are freed up, other components or structures can be set to further improve the optical imaging performance of the diffractive waveguide.

[0060] In an implementable manner, a grating structure is disposed in a local area on the surface of the monolithic waveguide substrate. The local area includes at least a left eye coupling region, a left eye coupling region, a right eye coupling region, and a right eye coupling region. The center position of the left eye coupling region and the center position of the left eye coupling region are 25-32 mm apart in the lateral direction and 5-15 mm apart in the longitudinal direction. The center position of the right eye coupling region and the center position of the right eye coupling region are 25-32 mm apart in the lateral direction and 5-15 mm apart in the longitudinal direction.

[0061] For example, refer to Figure 4 The figure shows a schematic diagram of a binocular diffractive waveguide in one embodiment. As can be seen from the figure, the monolithic waveguide substrate is divided into a left eye optical path region 110 and a right eye optical path region 120. The left eye optical path region 110 includes a left eye coupling region 111 and a left eye coupling region 112, and the right eye optical path region 120 includes a right eye coupling region 121 and a right eye coupling region 122.

[0062] In order to simultaneously consider the rationality and comfort of human factors engineering, the aesthetic appearance of the glasses, and the energy loss of diffraction transmission, the binocular connection of the monolithic waveguide substrate is made into a deep concave arc structure. The bottom of the groove of the deep concave arc structure is not higher than the higher of the center position of the left eye coupling area and the center position of the right eye coupling area, and the bottom of the groove of the deep concave arc structure is not lower than the lower of the lowest position of the left eye coupling area and the lowest position of the right eye coupling area.

[0063] For example, refer to Figures 1 to 4 The center positions of the left and right eye coupling regions are at the same height, while the lowest point of the left eye coupling region is lower than that of the right eye coupling region. The figure uses dashed lines to indicate the higher of the center positions of the left and right eye coupling regions, and the lower of the lowest points of the left and right eye coupling regions, respectively. It can be seen that the bottom of the groove in the deeply concave arc-shaped structure is neither higher nor lower than the higher of the center positions of the left and right eye coupling regions.

[0064] This application also specifically provides constraints that the waveguide outer contours of the left and right eye optical pathway regions should meet, to specifically guide the shape design and cutting of monolithic waveguide substrates in actual mass production. Among these constraints, the waveguide outer contours need to be designed to avoid crosstalk between the left and right eyes, including the sides of the recessed arc-shaped structure.

[0065] Implementably, a one-dimensional left-eye coupling grating is provided within the left-eye coupling region, and the unit vector in the direction of the one-dimensional left-eye coupling grating is... , The grating orientation angle of the one-dimensional left-coupled grating; after the image light rays are incident on the one-dimensional left-coupled grating and undergo diffraction, the +1 order is the working order, and the propagation direction of the -1 order should satisfy the following with respect to the outer contour of the waveguide in the right eye optical path region:

[0066]

[0067]

[0068]

[0069] in, The size of the left eye insertion region. The coordinates of the center position of the left eye insertion region are: The direction of incidence of image light rays into the left eye coupling region. The grating period of a one-dimensional left-coupled grating The refractive index of the monolithic waveguide substrate, The working wavelength of the left eye's optical path region. Let be the equation of the straight line containing the -1st order transmission direction in the left eye's optical path region. The equation of the curve containing the outer contour of the waveguide in the optical path region of the right eye is given.

[0070] It can be understood that when image light rays are incident on a one-dimensional left-coupled grating, diffraction produces +1 and -1 orders. The +1 order propagates towards the left eye coupling region and is the working order, while the -1 order propagates away from the left eye coupling region and is the non-working order. The -1 order continues to propagate towards the right eye optical path region after exiting the waveguide substrate from the side of the monolithic waveguide substrate. The lower boundary of the propagation path of the -1 order... Waveguide outer contour in the right eye optical path region Above, even if the waveguide outer contour of the right eye optical path region is not on the -1 order propagation path. Among them, when constructing the curve equation of the waveguide outer contour, a two-dimensional coordinate system is established with the centerline of the monolithic waveguide substrate as the Y-axis and the line connecting the center positions of the left and right eye coupling regions as the X-axis.

[0071] The same principle applies to the right eye optical path region. Specifically, a one-dimensional right-coupled-in grating can be installed within the right eye coupling region, and the unit vector in the direction of the one-dimensional right-coupled-in grating is... , Let be the grating orientation angle of the one-dimensional right-coupled grating; after the image light rays are incident on the one-dimensional right-coupled grating and undergo diffraction, the +1st order is the working order, and the propagation direction of the -1st order should satisfy the following with respect to the outer contour of the waveguide in the left eye optical path region:

[0072]

[0073]

[0074]

[0075] in, The size of the right eye insertion region. The coordinates of the center position of the right eye insertion region are: The direction of incidence of image light rays into the right eye coupling region. The grating period of a one-dimensional right-coupled grating. The refractive index of the monolithic waveguide substrate, The working wavelength of the right eye's optical path region. Let be the equation of the straight line containing the -1st order transmission direction in the right eye's optical path region. The equation of the curve containing the outer contour of the waveguide in the optical path region of the left eye is given.

[0076] It can be understood that when image light rays are incident on a one-dimensional right-coupled grating, diffraction produces +1 and -1 orders. The +1 order propagates towards the right eye's output region and is the working order, while the -1 order propagates away from the right eye's output region and is the non-working order. The -1 order continues to propagate towards the left eye's optical path region after exiting the waveguide substrate from the side of the monolithic waveguide substrate. The lower boundary of the propagation path of the -1 order... Waveguide outer contour in the left eye optical path region Above, even if the waveguide outer contour of the right eye optical path region is not on the -1 order propagation path. Among them, when constructing the curve equation of the waveguide outer contour, a two-dimensional coordinate system is established with the centerline of the monolithic waveguide substrate as the Y-axis and the line connecting the center positions of the left and right eye coupling regions as the X-axis.

[0077] This application also provides a near-eye display device, which includes a left-eye optical engine, a right-eye optical engine, and a binocular diffractive waveguide of any of the foregoing embodiments. The left-eye optical engine corresponds to the left-eye optical path area and is used to independently control the opening and closing of the left-eye optical path. The right-eye optical engine corresponds to the right-eye optical path area and is used to independently control the opening and closing of the right-eye optical path.

[0078] The near-eye display device provided in this application can freely switch between monocular and binocular display. In monocular display mode, it can achieve monochrome or color display. With the same battery volume, the monocular solution typically has a 30%-50% longer battery life than the binocular solution, making it more suitable for information prompts in mobile scenarios (such as navigation arrows and message notifications). In binocular display mode, it can achieve 3D stereoscopic display, providing an immersive visual experience and scenarios for precise interaction between virtual and real spaces.

[0079] In practice, the light beam emitted by the left-eye optical engine is coupled into the left-eye optical path area via the left-eye input grating. After being transmitted through total internal reflection inside the waveguide, it is coupled out by the left-eye output grating and enters the user's left pupil. Similarly, the light beam emitted by the right-eye optical engine enters the user's right pupil via the right-eye input grating, the right-eye optical path area, and the right-eye output grating. By independently controlling the on / off states of the left and right-eye optical engines, the device can not only achieve normal binocular stereoscopic display but also flexibly switch to monocular display mode to adapt to different application scenarios, such as in safe working scenarios where one eye needs to observe the surrounding environment, or in low-power standby mode where only monocular information is displayed.

[0080] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. 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 principles of this application should be included within the scope of protection of this application.

Claims

1. A binocular diffractive optical waveguide, characterized in that, include: A monolithic waveguide substrate, wherein the monolithic waveguide substrate has a left eye optical path region and a right eye optical path region, the left eye optical path region includes a left eye coupling region and a left eye coupling out region, and the right eye optical path region includes a right eye coupling in region and a right eye coupling out region; Both the left-eye coupling region and the right-eye coupling region are located close to the centerline of the monolithic waveguide substrate. By adjusting the propagation path and exit boundary of the diffraction order after the image light is diffracted by the grating structure in the left-eye coupling region, and by optimizing the waveguide outer contour of the right-eye optical path region, the non-working order of the image light after diffracting by the grating structure in the left-eye coupling region towards the right-eye optical path region does not enter the right-eye optical path region.

2. The binocular diffractive waveguide according to claim 1, characterized in that, The monolithic waveguide substrate is bilaterally symmetrical, and there is a local asymmetry above the midline; the center of the left eye coupling region and the center of the right eye coupling region are mirror symmetrical about the midline, and the size of the left eye coupling region is different from that of the right eye coupling region.

3. The binocular diffractive waveguide according to claim 2, characterized in that, The size of the left eye coupling region satisfy: The size of the right eye coupling region satisfy: Where L is the distance from the exit pupil of the projection optical engine to the monolithic waveguide substrate. The field of view of the left eye in the binocular diffractive waveguide. The field of view of the right eye in the binocular diffractive waveguide. The exit pupil diameter of the projection optical engine. The thickness of the monolithic waveguide substrate is given. The diffraction angle of the image light rays after passing through the left eye coupling region. The diffraction angle of the image light rays after passing through the right eye coupling region. The value range is 0.3–1 mm.

4. The binocular diffractive waveguide according to claim 1, characterized in that, A grating structure is disposed on the entire surface of the monolithic waveguide substrate. The center of the left eye optical path area corresponds to the center of the left eye pupil, and the center of the right eye optical path area corresponds to the center of the right eye pupil. The lateral dimension of the left eye optical path area and / or the right eye optical path area is 35-40 mm, and the longitudinal dimension of the left eye optical path area and / or the right eye optical path area is 35-40 mm. The lateral distance between the center of the left eye coupling area and the center of the left eye optical path area is 12-16 mm, and the longitudinal distance is 4-8 mm. The lateral distance between the center of the right eye coupling area and the center of the right eye optical path area is 12-16 mm, and the longitudinal distance is 4-8 mm.

5. The binocular diffractive waveguide according to claim 1, characterized in that, A grating structure is disposed in a local area on the surface of the monolithic waveguide substrate. The local area includes at least the left eye coupling region, the left eye coupling region, the right eye coupling region, and the right eye coupling region. The center position of the left eye coupling region and the center position of the left eye coupling region are 25-32 mm apart in the horizontal direction and 5-15 mm apart in the vertical direction. The center position of the right eye coupling region and the center position of the right eye coupling region are 25-32 mm apart in the horizontal direction and 5-15 mm apart in the vertical direction.

6. The binocular diffractive waveguide according to any one of claims 1-5, characterized in that, The binocular connection of the monolithic waveguide substrate is a deep concave arc structure. The bottom of the groove of the deep concave arc structure is not higher than the higher of the center position of the left eye coupling region and the center position of the right eye coupling region, and the bottom of the groove of the deep concave arc structure is not lower than the lower of the lowest position of the left eye coupling region and the lowest position of the right eye coupling region.

7. The binocular diffractive waveguide according to claim 6, characterized in that, A one-dimensional left-eye coupling grating is disposed within the left-eye coupling region, and the unit vector of the direction of the one-dimensional left-eye coupling grating is... , The grating orientation angle of the one-dimensional left-coupled grating; after the image light rays are incident on the one-dimensional left-coupled grating and undergo diffraction, the +1 order is the working order, and the transmission direction of the -1 order should satisfy the following with respect to the waveguide outer contour of the right eye optical path region: in, The size of the left eye coupling region. The coordinates of the center position of the left eye coupling region are given. The angle of incidence of image light rays onto the left eye coupling region. The grating period of the one-dimensional left-coupled grating is... The refractive index of the monolithic waveguide substrate is given by [reference to a specific parameter]. The operating wavelength of the left eye optical path region is [not specified]. Let be the equation of the straight line containing the -1st order transmission direction of the left eye optical path region. The equation of the waveguide outer contour of the right eye optical path region is given.

8. The binocular diffractive waveguide according to any one of claims 1-5, characterized in that, The left eye optical path area and the right eye optical path area transmit image light in different wavelengths.

9. The binocular diffractive waveguide according to claim 7, characterized in that, The image light transmitted in one of the optical paths of the left eye and the right eye is in the red-green band, and the image light transmitted in the other optical path is in the blue-green band; or, the image light transmitted in one of the optical paths of the left eye and the right eye is in the full band, and the image light transmitted in the other optical path is in the green band.

10. A near-eye display device, characterized in that, The device includes a left-eye optical transducer, a right-eye optical transducer, and a binocular diffractive waveguide as described in any one of claims 1-9, wherein the left-eye optical transducer corresponds to the left-eye optical path region and is used to independently control the opening and closing of the left-eye optical path; the right-eye optical transducer corresponds to the right-eye optical path region and is used to independently control the opening and closing of the right-eye optical path.

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