Edge display diffraction optical waveguide and design method and application thereof

Abstract

The invention relates to an edge display diffraction optical waveguide and a design method and application thereof. The diffraction optical waveguide comprises a coupling-in area, a transition area and a coupling-out area which are sequentially arranged along a light beam transmission path. Wherein a light beam transmission path needs to meet a grating vector closing relation, so that after being totally reflected in the diffraction optical waveguide, a light beam incident from the coupling-in region is emitted through the coupling-out region and is imaged in an edge view field region of the diffraction optical waveguide; the width and height of the out-of-coupling area in the eye head-up field are determined according to the eye movement range, the exit pupil distance and the field area; the range of the coupling-in area is determined according to a preset distance between the coupling-in area and the coupling-out area; the range of the turning region is determined according to a k-vector range from the coupling-in region to the coupling-out region and a k-vector range from the coupling-in region to the turning region. According to the invention, the virtual image is presented in the edge view field area without shielding the central view field area, so that not only can good combination of virtual and real scenes be realized, but also the problems of rainbow lines, light leakage and the like can be well avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of diffraction optical waveguides, and in particular to a diffraction optical waveguide for edge display and a design method and application thereof. Background Art

[0002] Augmented Reality (AR) technology is a technology that cleverly integrates virtual information with the real world. It widely uses multimedia, three-dimensional modeling, real-time tracking and registration, intelligent interaction, sensing and other technical means to simulate computer-generated text, images, three-dimensional models, music, video and other virtual information, and apply them to the real world. The two types of information complement each other, thereby achieving "enhancement" of the real world. AR glasses use AR technology. AR glasses are a sci-fi product pioneered by Google. It is also a product with avant-garde technology. Wearing it can experience the future functions used by handsome male and female protagonists in sci-fi movies. At the same time, AR glasses can realize many functions. It can be regarded as a miniature mobile phone. It can determine the user's state by tracking the eye's line of sight, and can turn on the corresponding function. For example, when you need to make a call or send a text message, you only need to turn on the voice input information.

[0003] Due to the difficult-to-solve production yield problem of array optical waveguides and the stripe problem of multiple semi-transparent and semi-reflective mirrors that affect the appearance, diffraction optical waveguides have become the mainstream of practical applications of consumer-grade AR glasses. However, diffraction optical waveguides also have a series of problems such as inconsistent diffraction angles of visible light of different wavelengths, rainbow stripes, difficulty in reducing weight and thinness, low light transmission efficiency, and forward light leakage of glasses. In September 2024, Qiu Min, Guoqiang Chair Professor and Vice President of West Lake University and Chief Scientist of the Applicant, demonstrated a pair of ultra-light and thin silicon carbide AR glasses in the Zhejiang Association for Science and Technology Building, achieving a single-chip full-color display, no rainbow stripes, extremely light lenses (2.7g), extremely thin lenses (0.55mm), and a binocular weight of only 5.4g. This is not only the debut of the glasses, but also the world's first launch of the scientific and technological achievement of "extremely light and thin silicon carbide AR diffraction optical waveguide without rainbow stripes", which can "project" optical images on transparent lenses, and while seeing electronic images, it will not block the real world.

[0004] Existing consumer-grade AR glasses are divided into two types: single green display and full color display. Single green waveguide can meet the demand for a larger FOV; while color waveguide is limited by the image source device and the refractive index of the lens material, and usually has a smaller FOV. The two have their own imaging characteristics, but are difficult to merge. In addition to the various technical difficulties of the light engine and light transmission components, it is difficult to have a perfect solution. A larger FOV (virtual image display field of view), a larger EyeBox (to adapt to the interpupillary distance between the eyes of most people), and a higher eye brightness are also crucial for the actual experience of AR glasses. For example, a Chinese patent with authorization announcement number CN113777785B discloses a diffraction optical waveguide AR system, including: a display unit, a collimating lens group, a reflector, a coupling-in grating, an optical waveguide plate, and a coupling-out grating; the width W of the coupling-out grating under the human eye's head-on field of view is out and height H out Satisfies the following formula: W out =Eyebox W +2ERF×tan(FOV W / 2); H out =Eyebox H +2ERF×tan(FOV H / 2); among them, Eyebox W is the width of the eye movement range, Eyebox H is the eye movement range height, ERF is the pupil distance, FOV W is the width of the field of view, FOV H The diffraction waveguide deflects the parallel light path emitted by the collimating lens group, and finally makes the light vertically incident on the coupling grating area of ​​the waveguide, which can reduce the distance between the coupling grating and the coupling grating, so as to increase the size of FOV and Eyebox and enhance the visual effect.

[0005] At present, the virtual images of AR glasses are usually presented in front of the human eye. With the improvement of the brightness of the diffraction optical waveguide and the increase in the user's field of view (FOV), the virtual image will block the line of sight of the real environment to a certain extent, especially when used in outdoor environments, which will cause inconvenience and even danger. Therefore, the industry has been continuously improving and striving for breakthroughs around the design of different micro-display light engines, optical waveguide substrate materials, and diffraction optical waveguides. At the same time, the applicant found that when using AR glasses in outdoor scenes, users need information prompts more, such as brief information such as text messages, weather, heart rate, etc., and these information themselves do not need to occupy the complete field of vision in front of the human eye, but only need to be imaged at the edge of the line of sight, and the central field of view area in front of the human eye can be vacated, which is convenient for the wearer of the glasses to observe the real environment and interact with people. On this basis, in order to meet the needs of large FOV, full color, and edge information prompts, the purpose of large FOV is to display useful information on the edge as much as possible while ensuring that the human eye can easily receive information, so that more central field of view can be used for observing real scenes, and full color is to ensure the richness of information prompts, which is more in line with current consumer needs. Based on this, a diffraction optical waveguide for edge information prompts is developed, and it is matched with an image source device with specific angle output, which can realize the display function of full-color information prompts within a large FOV range, which is a problem that needs to be solved urgently. Summary of the invention

[0006] In view of the shortcomings of the prior art, the first purpose of the present invention is to provide a diffractive optical waveguide for edge display. This large FOV full-color diffractive optical waveguide can present virtual images in the edge field of view without blocking the central field of view. It can not only achieve a good combination of virtual and real scenes, but also avoid rainbow patterns, light leakage and other problems.

[0007] The second object of the present invention is to provide a design method of a diffractive optical waveguide for edge display, which has the advantages of flexible design and easy to obtain a diffractive optical waveguide for edge display.

[0008] The second object of the present invention is to provide an application of a diffractive optical waveguide for edge display, which achieves the goals of large FOV, full color, and edge information prompting.

[0009] To achieve the above first object, the present invention provides the following technical solutions: A diffractive optical waveguide with edge display includes an incoupling region (IC), an energizing region (EPE) and an outcoupling region (OC) arranged in sequence along a light beam transmission path; wherein: The light beam transmission path must satisfy the grating vector closure relationship, so that the light beam incident in the coupling-in region is totally reflected in the diffraction light waveguide, then emitted through the coupling-out region and imaged in the edge field of view of the diffraction light waveguide; The width and height of the outcoupling area under the human eye's horizontal field of view are determined according to the eye movement range (EyeBox), the exit pupil distance (ERF) and the field of view (FOV); The range of the coupling-in region is determined according to a predetermined distance between the coupling-in region and the coupling-out region; The range of the turning zone is determined according to the k-vector range from the coupling-in zone to the coupling-out zone, and the k-vector range from the coupling-in zone to the turning zone; The k-vector range is determined according to the beam transmission path and the outcoupling field of view area within the k-domain boundary.

[0010] Specifically, in the "diffractive optical waveguide" of the present invention, The specific meaning of the “light beam transmission path” is the path of the light beam starting from the light source, passing through the following optical waveguide, coupling-in area, turning area and out-coupling area in sequence, diffracted and totally reflected, and forming a virtual screen image (i.e., imaging of the edge field of view area to form information prompt content) in front of the human eye; wherein the light source is located directly above the coupling-in area, and the coupling-in area, turning area and out-coupling area are on the substrate surface, and can be located on the same side or distributed on both sides of the substrate; The "incoupling area" is usually set as a circular or rectangular area, and its size is determined by the light output aperture of the image source device (optical machine) (used to collect all the light from the optical machine). Therefore, after determining the center position of the incoupling area, that is, the relative position of the incoupling area and the outcoupling area, the range of the incoupling area on the optical waveguide sheet described below can be determined; The same is true for the "turning zone". After determining the range of the coupling-in zone and the coupling-out zone, based on the maximum and minimum values ​​of the two k-vector ranges, refer to Figure 2 , determine the boundaries of the turning zone, and then determine the scope of the turning zone on the optical waveguide sheet described below.

[0011] Furthermore, the edge viewing area is one or a combination of viewing areas having a vertical viewing angle range outside ±5° and / or a horizontal viewing angle range outside ±5°.

[0012] For example, the edge viewing area may be a viewing area with a vertical viewing angle ranging from -35 to 35° and a horizontal viewing angle ranging from -35 to -5°; And / or, the edge viewing area is a viewing area with a vertical viewing angle range of 5 to 35° and a horizontal viewing angle range of 5 to 35°; And / or, the edge viewing area is a viewing area with a vertical viewing angle range of 5 to 35° and a horizontal viewing angle range of -35 to 35°; And / or, the edge viewing area is a viewing area with a vertical viewing angle range of -35 to -5° and a horizontal viewing angle range of -35 to -5°.

[0013] Furthermore, the diffraction optical waveguide also includes an optical waveguide plate, the coupling-in region, the turning region and the coupling-out region are arranged on the optical waveguide plate, and the optical waveguide plate is set to be a combined substrate of at least two of high-refractive glass (n≥2.0@632nm), lithium niobate (n=2.2@632nm), silicon carbide (n=2.6@632nm), or a low-refractive optical substrate (n=1.7~1.9@632nm).

[0014] From the perspective of the lens, a transparent material with a higher refractive index can be selected as the lens base, or the refractive index of the lens base can be lowered accordingly. By stacking two or three lenses, the full-color requirements of a large FOV can also be achieved.

[0015] Furthermore, the diffraction optical waveguide also includes a coupling-in grating, a turning grating and a coupling-out grating, and the coupling-in grating, the turning grating and the coupling-out grating are respectively arranged on the coupling-in region, the turning region and the coupling-out region, and the coupling-in grating, the turning grating and the coupling-out grating are respectively set to high-refractive glass (n≥2.0@632nm), lithium niobate (n=2.2@632nm), silicon carbide (n=2.6@632nm), optical resin (n=1.7~3.0@632nm), ceramic coating material (TiO2, Si3N4, etc.), or liquid crystal material.

[0016] From the perspective of grating, the grating type can be surface relief grating, volume holographic grating, etc. The optional material refractive index can be arbitrarily set from the range of n=1.7~3.0 to meet the increased coupling efficiency. The material can be an organic material such as embossed glue, or a resin material, or the material of the optical waveguide itself, or a ceramic coating material such as TiO2, Si3N4, etc., or a liquid crystal material, etc.

[0017] Furthermore, 1 to 2 turning zones are provided, 1 to 2 outcoupling zones are provided correspondingly, and the coupling-in grating, the turning grating and the outcoupling grating are arranged one-to-one correspondingly to the coupling-in zone, the turning zone and the outcoupling zone respectively.

[0018] From the perspective of optical waveguide design, diffraction optical waveguides no longer need to ensure the outcoupling of light in the entire FOV range, but only need to ensure the outcoupling of light in some edge areas. In this way, the k-space and layout can be re-optimized and designed to ensure that the field of view in the imaging area meets the total reflection conditions in the waveguide and is coupled out to the human eye. The corresponding layout can be further compressed, especially for the turning grating, so that the lens area can be further compressed to improve the aesthetics.

[0019] To achieve the above second purpose, the present invention provides the following technical solutions: A method for designing a diffractive optical waveguide for edge display comprises the following steps: S1 determines the width and height of the out-coupling zone under the human eye's horizontal field of view according to the target parameters, and determines the predetermined distance between the in-coupling zone and the out-coupling zone and the position of the turning zone relative to the in-coupling zone and the out-coupling zone in turn in combination with the light source position, thereby determining the light beam transmission path; S2: according to the beam transmission path, a k-domain diagram of the light beam imaged in the edge field of view area propagating in the diffraction optical waveguide is established, and the out-coupling field of view area is within the k-domain boundary, and the coupling-in area, the turning area and the out-coupling area satisfy the grating vector closure relationship, and then the k-vector range from the coupling-in area to the out-coupling area and the k-vector range from the coupling-in area to the turning area are determined, and finally the range of the coupling-in area and the turning area are determined; S3 determines the grating parameters of the coupling-in grating, the turning grating and the coupling-out grating based on the coupling-in region, the turning region and the coupling-out region determined by S1 and S2 and according to the preset material parameters of the diffraction optical waveguide to obtain the diffraction optical waveguide.

[0020] Furthermore, in S1, the target parameters are the eye box (EyeBox), the exit pupil distance (ERF) and the field of view (FOV), and the specific calculation method is as follows: OC x =EB x +2*ER*tan(FOV H / 2), OC y =EB y +2*ER*tan(FOV V / 2); Among them, OC x , OC y are the width and height of the outcoupling region, EB x , EB y are the width and height of the eye movement range, ER is the exit pupil distance, FOV H FOV V They are the vertical field of view angle range and the horizontal field of view angle range of the field of view area respectively.

[0021] Furthermore, in said S1, EB x , EB y They are 12~15mm and 10mm respectively, ER is 16~18mm, field of view is 70~75°, FOV H FOV V They are 58.4~63.0° and 45.6~49.4° respectively. Further, in S1, the predetermined distance between the coupling-in area and the coupling-out area is -40 to 50 mm in the horizontal direction and -10 to 30 mm in the vertical direction.

[0022] Further, in S2, a k-vector range k1 from the coupling-in region to the decoupling region is -2.00 to 2.00, and a k-vector range k2 from the coupling-in region to the turning region is -4.00 to 4.00.

[0023] Furthermore, in S3, the period P1 of the coupling-in grating is 270~320nm, the grating vector direction X1 is -40~60°, the turning grating P2 is 175~220nm, the grating vector direction X2 is -45~85°, and the coupling-out grating P2 is 79~257nm, the grating vector direction X2 is -24~90°.

[0024] To achieve the third objective, the present invention provides the following technical solutions: The invention discloses an application of a diffractive optical waveguide for edge display in a display device.

[0025] Furthermore, the display device includes a mobile phone, a tablet computer, a laptop computer, a desktop computer display, a smart watch, a naked-eye 3D display screen, VR glasses, AR glasses, a smart bracelet, a smart ring, a camera, smart glasses, a smart checkout counter display, a shelf electronic tag, a smart shopping cart display, an access control display, a vehicle-mounted central console, a makeup mirror, a projector, a refrigerator display, a head-up display, a vehicle-mounted display, a projection screen, or a TV display.

[0026] Furthermore, the AR glasses include an image source device and the above-mentioned diffraction optical waveguide, and the image source device is arranged on the light incident side of the coupling zone along the light beam transmission path and incidents the light beam into the coupling zone.

[0027] From the perspective of matching image source devices (optical machines), we can consider presenting partial information prompts to the left and right eyes respectively, and then making the picture complete by combining the images; we can also present the same information to the left and right eyes; even in order to meet the needs of edge imaging, we can also match multiple sets of optical machines to present different pictures at different edge positions of the field of view. The position of the optical machine can be near the temple of the glasses, that is, away from the nose wing, or near the nose wing.

[0028] In summary, the beneficial technical effects of the present invention are as follows: the diffraction optical waveguide in the AR glasses can project the virtual picture from the image source device in front of the human eyes, so as to realize the superposition of the virtual picture and the real scene. For AR glasses worn outdoors, information prompt is one of the most important functions. Different from the requirement of conventional AR glasses to display virtual pictures in full FOV, information prompt often does not need to occupy too much display space, and only needs to provide information content at the edge of the human eye's field of view. In this way, the central field of view can better observe the display scene to achieve better virtual-real fusion; however, the diffraction optical waveguides in the current AR glasses are all full-frame displays, which results in a virtual picture always being superimposed in front of the human eye, thereby blocking the user from observing the external environment; based on such actual needs and existing problems, the present invention proposes a full-color optical waveguide with a large FOV that can realize edge display, and the virtual color picture is only presented at the edge of the field of view, and will not block the central field of view. Such a diffraction optical waveguide can not only realize a good combination of virtual and real scenes, but also can well avoid the problems that often occur in waveguides such as rainbow patterns and light leakage, and has practical use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of the diffraction optical waveguide with edge display according to Example 1 of the present invention.

[0030] Figure 2 It is the k-domain diagram of embodiment 3 of the present invention.

[0031] Figure 3 It is the k-space diagram of Example 3 of the present invention.

[0032] Figure 4 This is the layout diagram of embodiment 3 of the present invention.

[0033] Figure 5 It is the k-space diagram of embodiment 4 of the present invention.

[0034] Figure 6 This is the layout diagram of embodiment 4 of the present invention.

[0035] Figure 7 It is the k-space diagram of Example 5 of the present invention.

[0036] Figure 8 This is the layout diagram of Example 5 of the present invention. DETAILED DESCRIPTION

[0037] In order to make the technical means, creative features, objectives and functions achieved by the present invention clearer and easier to understand, the present invention is further explained below in conjunction with the accompanying drawings and specific implementation methods.

[0038] Embodiment 1: A diffractive optical waveguide with edge display disclosed in the present invention comprises an optical waveguide plate, an incoupling grating, a turning grating and an outcoupling grating, wherein the optical waveguide plate is provided with an incoupling region (IC), an turning region (EPE) and an outcoupling region (OC) arranged in sequence along the light beam transmission path, and the incoupling grating, the turning grating and the outcoupling grating are respectively arranged on the incoupling region, the turning region and the outcoupling region; wherein, The optical waveguide is configured as a composite substrate of at least two of high-refractive glass (n≥2.0@632nm), lithium niobate (n=2.2@632nm), silicon carbide (n=2.6@632nm), or a low-refractive optical substrate (n=1.7~1.9@632nm); The coupling-in grating, turning grating and coupling-out grating are respectively set to high-refractive glass (n≥2.0@632nm), lithium niobate (n=2.2@632nm), silicon carbide (n=2.6@632nm), optical resin (n=1.7~3.0@632nm), ceramic coating material (TiO2, Si3N4, etc.), or liquid crystal material.

[0039] The beam transmission path must satisfy the grating vector closure relationship, so that the incident beam in the coupling-in area is totally reflected in the diffraction waveguide, then emitted through the coupling-out area and imaged in the edge field of view of the diffraction waveguide; The width and height of the outcoupling area under the human eye's horizontal field of view are determined according to the eye movement range (EyeBox), exit pupil distance (ERF) and field of view (FOV); The range of the incoupling region is determined according to a predetermined distance between the incoupling region and the outcoupling region; The range of the turning zone is determined according to the k-vector range from the incoupling zone to the outcoupling zone and the k-vector range from the incoupling zone to the turning zone; The k-vector range is determined by the beam propagation path and the outcoupling field of view within the k-domain boundary.

[0040] Reference Figure 1 The present invention also discloses an application of the above-mentioned diffractive optical waveguide of edge display in a display device, and the display device is AR glasses, which includes an image source device and the above-mentioned diffractive optical waveguide. The image source device is arranged on the light incident side of the coupling zone along the light beam transmission path and incidents the light beam into the coupling zone.

[0041] Embodiment 2 is a diffractive optical waveguide with edge display disclosed in the present invention, which is different from Embodiment 1 in that it includes the following steps: S1 determines the width and height of the out-coupling zone under the human eye's horizontal field of view according to the target parameters, and determines the predetermined distance between the in-coupling zone and the out-coupling zone, and the position of the turning zone relative to the in-coupling zone and the out-coupling zone in turn in combination with the light source position, thereby determining the light beam transmission path; S2 establishes a k-domain diagram of the light beam imaged in the edge field of view area propagating in the diffraction optical waveguide according to the light beam transmission path, and makes the out-coupling field of view area within the k-domain boundary, and the coupling-in area, the turning area and the out-coupling area satisfy the grating vector closure relationship, and then determines the k-vector range from the coupling-in area to the out-coupling area, and the k-vector range from the coupling-in area to the turning area, and finally determines the range of the coupling-in area and the turning area; S3 determines the grating parameters of the coupling-in grating, the turning grating and the coupling-out grating based on the coupling-in region, the turning region and the coupling-out region determined by S1 and S2 and according to the preset material parameters of the diffraction optical waveguide to obtain the diffraction optical waveguide.

[0042] Embodiment 3 is a diffractive optical waveguide with edge display disclosed in the present invention, which is different from Embodiment 2 in that it includes the following steps: S1 When the edge field of view is located on the lower side of the lens and the image source device is located near the temple of the AR glasses, the width of the eye movement range EB x 12mm, height EB y The exit pupil distance ER is 10mm, the field of view is 70°, and the horizontal field of view angle range FOV H FOV is 58.4° vertical field of view V is 45.6°, according to the formula OC x =EB x +2*ER*tan(FOV H / 2), OC y =EB y +2*ER*tan(FOV V / 2), the width OC of the outcoupling area under the human eye's horizontal field of view can be calculated x 32.12mm, height OC y 25.13mm; According to the above-mentioned image source device, taking the left eye display as an example, the coupling-in area is approximately located at the left edge of the left lens, so the coupling-out area should be located in the blank area on the right side of the coupling-in area; assuming that the predetermined distance between the center of the coupling-out area and the center of the coupling-in area is 30 mm in the horizontal direction and 30 mm in the vertical direction, that is, the coupling-out area is located at the upper right position of the coupling-in area; considering that the actual grating area is arranged as compactly as possible to reduce the actual area of ​​the AR lens, the turning area can be set to the right side of the coupling-in area and below the coupling-out area, thereby determining the beam transmission path; S2 When the edge field of view area is located at the lower side of the lens, that is, the edge field of view area is the field of view area with a horizontal field of view angle range of -29.2~29.2° and a vertical field of view angle range of -22.8~-7.6°, and the optical waveguide, coupling grating, turning grating and coupling grating are all set to silicon carbide (n=SiC@632nm), refer to Figure 2, a k-domain diagram of the light beam imaged in the edge field of view area propagating in the diffractive optical waveguide is established. The diagram represents the propagation process of blue light, green light and red light from left to right, and the arrow represents the grating vector direction X. Since the image to be displayed is only the edge position of the full frame, the unnecessary part of the field of view can be allowed to move out of the k-domain boundary, which can further expand the design flexibility; Combined with the beam transmission path determined by S1, refer to Figure 3 , the corresponding k-space diagram can be drawn. The outcoupling field of view is within the k-domain boundary, and the coupling-in region, turning region and outcoupling region satisfy the grating vector closure relationship. According to the calculation, the k-vector range from the coupling-in region to the outcoupling region is: k 1max =-0.67, k 1min =-1.68, k vector range from coupling region to transition region 2max =1.28, k 2min =0.49, finally determine the range of coupling zone and turning zone; S3 is based on the coupling-in region, turning region and coupling-out region determined by S1 and S2, and according to the preset material parameters of the diffractive optical waveguide, referring to Figure 4 , further calculated to obtain the corresponding diffraction waveguide layout distribution diagram, and determined that the period P1 of the coupling grating is 295nm, the grating vector direction X1 is 10°, the turning grating P2 is 212nm, the grating vector direction X2 is -45°, the coupling-out grating P2 is 254.8nm, and the grating vector direction X2 is 90°; wherein, the gray rectangle represents the partial cross-section of the grating lines of the coupling-in grating, the turning grating and the coupling-out grating in the XZ plane, and the above grating lines extend along the Y direction and fill the coupling-in area, the turning area and the coupling-out area respectively, the same below; AR glasses are equipped with two image source devices on both sides. The images displayed by the left and right eyes are consistent. Through binocular imaging, a complete information prompt screen can be presented at the edge of the human eye's line of sight. The grating vector direction is defined according to the direction of the left waveguide. The right waveguide can be mirrored to obtain a diffraction light waveguide.

[0043] Embodiment 4 is a diffractive optical waveguide with edge display disclosed in the present invention, which is different from Embodiment 2 in that it includes the following steps: S1 When the edge field of view is located on the lower side of the lens and the image source device is located near the temple of the AR glasses, the width of the eye movement range EB x 15mm, height EB y The exit pupil distance ER is 16mm, the field of view is 75°, and the horizontal field of view angle range FOV H FOV is 63° vertical field of view V is 49.4°, according to the formula OC x =EB x+2*ER*tan(FOV H / 2), OC y =EB y +2*ER*tan(FOV V / 2), the width OC of the outcoupling area under the human eye's horizontal field of view can be calculated x 34.61mm, height OC y 24.71mm; According to the above-mentioned image source device, taking the left eye display as an example, the coupling-in area is approximately located at the left edge of the left lens, so the coupling-out area should be located in the blank area on the right side of the coupling-in area; assuming that the predetermined distance between the center of the coupling-out area and the center of the coupling-in area is 50 mm in the horizontal direction and -10 mm in the vertical direction, that is, the coupling-out area is located at the lower right position of the coupling-in area; considering that the actual grating area is arranged as compactly as possible to reduce the actual area of ​​the AR lens, the turning area can be set in the middle of the coupling-in area and the coupling-out area, thereby determining the beam transmission path; S2 When the edge field of view area is located on the left side of the lens, that is, the edge field of view area is the field of view area with a horizontal field of view angle range of -31.5~-10.5° and a vertical field of view angle range of -24.7~24.7°, and the optical waveguide, coupling-in grating, turning grating and coupling-out grating are all set to silicon carbide (n=2.6@632nm), a k-domain diagram of the light beam imaged in the edge field of view area propagating in the diffraction optical waveguide is established. The diagram represents the propagation process of blue light, green light and red light from left to right, and the arrow represents the grating vector direction X. Since the image to be displayed is only the edge position of the full frame, the unnecessary part of the field of view can be allowed to move out of the k-domain boundary, which can further expand the design flexibility; Combined with the beam transmission path determined by S1, refer to Figure 5 , the corresponding k-space diagram can be drawn. The outcoupling field of view is within the k-domain boundary, and the coupling-in region, turning region and outcoupling region satisfy the grating vector closure relationship. According to the calculation, the k-vector range from the coupling-in region to the outcoupling region is: k 1max =0.25, k 1min =-0.06, k vector range from coupling region to transition region 2max =3.73, k 2min =-3.73, finally determine the range of coupling zone and turning zone; S3 is based on the coupling-in region, turning region and coupling-out region determined by S1 and S2, and according to the preset material parameters of the diffractive optical waveguide, referring to Figure 6 , and further calculated the corresponding diffraction waveguide layout distribution diagram, determining that the period P1 of the coupling grating is 270nm, the grating vector direction X1 is -40°, the turning grating P2 is 220nm, the grating vector direction X2 is 85°, and the coupling grating P2 is 257nm, the grating vector direction X2 is 34°; AR glasses are equipped with two image source devices on both sides. The images displayed by the left and right eyes are consistent. Through binocular imaging, a complete information prompt screen can be presented at the edge of the human eye's line of sight. The grating vector direction is defined according to the direction of the left waveguide. The right waveguide can be mirrored to obtain a diffraction light waveguide.

[0044] Embodiment 5 is a diffractive optical waveguide with edge display disclosed in the present invention, which is different from Embodiment 2 in that it includes the following steps: S1 When the edge field of view is located on the lower side of the lens and the image source device is located near the nose of the AR glasses, the width of the eye movement range EB x 12mm, height EB y The exit pupil distance ER is 16mm, the field of view is 70°, and the horizontal field of view angle range FOV H FOV is 58.4° vertical field of view V is 45.6°, according to the formula OC x =EB x +2*ER*tan(FOV H / 2), OC y =EB y +2*ER*tan(FOV V / 2), the width OC of the outcoupling area under the human eye's horizontal field of view can be calculated x 29.88mm, height OC y 23.45mm; According to the above-mentioned image source device, taking the left eye display as an example, the coupling-in area is approximately located at the right edge of the left lens, so the coupling-out area should be located in the blank area on the right side of the coupling-in area; assuming that the predetermined distance between the center of the coupling-out area and the center of the coupling-in area is -40 mm in the horizontal direction and 0 mm in the vertical direction, that is, the coupling-out area is located on the left side of the coupling-in area; considering that the actual grating area is arranged as compactly as possible to reduce the actual area of ​​the AR lens, the turning area can be set in the middle of the coupling-in area and the coupling-out area, thereby determining the beam transmission path; S2 When the edge field of view area is located on the left and right sides of the lens, that is, the edge field of view area is the horizontal field of view angle range of -29.2~-15.0° and The k-domain diagram of the light beam imaged in the edge field of view area propagating in the diffraction waveguide is established. From left to right in the figure, the propagation process of blue light, green light and red light is represented respectively. The arrow represents the grating vector direction X. Since the image to be displayed is only the edge position of the full frame, the unnecessary part of the field of view can be allowed to move out of the k-domain boundary, which can further expand the design flexibility. Combined with the beam transmission path determined by S1, refer to Figure 7 , the corresponding k-space diagram can be drawn. The outcoupling field of view is within the k-domain boundary, and the coupling-in region, turning region and outcoupling region satisfy the grating vector closure relationship. According to the calculation, the k-vector range from the coupling-in region to the outcoupling region is: k 1max =1.70, k 1min = 0.77, k vector range from coupling region to transition region 2max =-1.41, k 2min =-3.48, finally determine the range of coupling zone and turning zone; S3 is based on the coupling-in region, turning region and coupling-out region determined by S1 and S2, and according to the preset material parameters of the diffractive optical waveguide, referring to Figure 8 , and further calculated the corresponding diffraction waveguide layout distribution diagram, determining that the period P1 of the coupling grating is 320nm, the grating vector direction X1 is 60°, the turning grating P2 is 175nm, the grating vector direction X2 is 80°, the coupling grating P2 is 79nm, and the grating vector direction X2 is -24°; AR glasses are equipped with two image source devices on both sides. The images displayed by the left and right eyes are consistent. Through binocular imaging, a complete information prompt screen can be presented at the edge of the human eye's line of sight. The grating vector direction is defined according to the direction of the left waveguide. The right waveguide can be mirrored to obtain a diffraction light waveguide.

[0045] The heating method of the above-mentioned embodiment provides a design method for an optical waveguide layout for edge display, and a method for determining a grating period and a grating vector in a corresponding grating region. The structure used in a specific grating region can be adjusted on the basis of satisfying period conditions, such as a straight grating, a blazed grating, a tilted grating, a trapezoidal grating, etc. In addition, in order to further improve the efficiency, the surface of the grating structure can also be subjected to coating, filling and other treatments.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A diffractive optical waveguide for edge display, characterized in that: It includes a coupling-in region, a turning region and a coupling-out region which are sequentially arranged along the light beam transmission path; wherein, The light beam transmission path must satisfy the grating vector closure relationship, so that the light beam incident in the coupling-in region is totally reflected in the diffraction light waveguide, then emitted through the coupling-out region and imaged in the edge field of view of the diffraction light waveguide; The width and height of the outcoupling area under the horizontal field of view of the human eye are determined according to the eye movement range, the exit pupil distance and the field of view area; The range of the coupling-in region is determined according to a predetermined distance between the coupling-in region and the coupling-out region; The range of the turning zone is determined according to the k-vector range from the coupling-in zone to the coupling-out zone, and the k-vector range from the coupling-in zone to the turning zone; The k-vector range is determined according to the beam transmission path and the outcoupling field of view area within the k-domain boundary.

2. The diffractive optical waveguide for edge display according to claim 1, characterized in that: The edge viewing area is one or a combination of viewing areas where the vertical viewing angle range is outside ±5° and / or the horizontal viewing angle range is outside ±5°.

3. The diffractive optical waveguide for edge display according to claim 1, characterized in that: The diffraction optical waveguide also includes an optical waveguide plate, the coupling-in region, the turning region and the coupling-out region are arranged on the optical waveguide plate, and the optical waveguide plate is configured as a composite substrate of at least two of high-refractive glass, lithium niobate, silicon carbide, or low-refractive optical substrates.

4. The diffractive optical waveguide for edge display according to claim 1, characterized in that: The diffraction optical waveguide also includes a coupling-in grating, a turning grating and a coupling-out grating, and the coupling-in grating, the turning grating and the coupling-out grating are respectively arranged on the coupling-in region, the turning region and the coupling-out region, and the coupling-in grating, the turning grating and the coupling-out grating are respectively set to high-refractive glass, lithium niobate, silicon carbide, optical resin, ceramic coating material, or liquid crystal material.

5. The design method of a diffractive optical waveguide for edge display according to any one of claims 1 to 4, characterized in that: The following steps are included: S1 determines the width and height of the out-coupling zone under the human eye's horizontal field of view according to the target parameters, and determines the predetermined distance between the in-coupling zone and the out-coupling zone and the position of the turning zone relative to the in-coupling zone and the out-coupling zone in turn in combination with the light source position, thereby determining the light beam transmission path; S2: according to the beam transmission path, a k-domain diagram of the light beam imaged in the edge field of view area propagating in the diffraction optical waveguide is established, and the out-coupling field of view area is within the k-domain boundary, and the coupling-in area, the turning area and the out-coupling area satisfy the grating vector closure relationship, and then the k-vector range from the coupling-in area to the out-coupling area and the k-vector range from the coupling-in area to the turning area are determined, and finally the range of the coupling-in area and the turning area are determined; S3 determines the grating parameters of the coupling-in grating, the turning grating and the coupling-out grating based on the coupling-in region, the turning region and the coupling-out region determined by S1 and S2 and according to the preset material parameters of the diffraction optical waveguide to obtain the diffraction optical waveguide.

6. The design method of a diffractive optical waveguide for edge display according to claim 5, characterized in that: In S1, the target parameters are the eye box, exit pupil distance (ERF), and field of view (FOV). The specific calculation method is: OC x =EB x +2*ER*tan(FOV H / 2),OC y =EB y +2*ER*tan(FOV V / 2); Among them, OC x , OC y are the width and height of the outcoupling region, EB x , EB y are the width and height of the eye movement range, ER is the exit pupil distance, FOV H FOV V They are the vertical field of view angle range and the horizontal field of view angle range of the field of view area respectively.

7. The design method of a diffractive optical waveguide for edge display according to claim 5, characterized in that: In S1, the predetermined distance between the coupling-in area and the coupling-out area is -40 to 50 mm in the horizontal direction and -10 to 30 mm in the vertical direction.

8. The design method of a diffractive optical waveguide for edge display according to claim 5, characterized in that: In S2, the k-vector range k1 from the coupling-in region to the decoupling region is -2.00 to 2.00, and the k-vector range k2 from the coupling-in region to the turning region is -4.00 to 4.

00.

9. The design method of a diffractive optical waveguide for edge display according to claim 5, characterized in that: In S3, the period P1 of the coupling-in grating is 270~320nm, the grating vector direction X1 is -40~60°, the turning grating P2 is 175~220nm, the grating vector direction X2 is -45~85°, and the coupling-out grating P2 is 79~257nm, the grating vector direction X2 is -24~90°.

10. Application of a diffractive optical waveguide for edge display according to any one of claims 1 to 4 in a display device.

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