Near-eye display device

Abstract

A kind of near-eye display device.The near-eye display device includes projection light machine, each projection light machine includes display screen, prism group and lens structure, prism group is located at the light exit side of display screen, prism group includes light entrance surface and light exit surface, different light entrance surfaces are configured to be incident different color image light, display screen is set up one by one with light entrance surface;Lens structure is located at the side where the light exit surface of prism group is located, prism group includes prism, and lens structure includes lens.The light entrance surface corresponding to one of the plurality of display screens is crossed by the assembly center axis of projection light machine, the screen center of the above one display screen is offset from the assembly center axis by a certain distance to make the chief ray of central field of view emitted from projection light machine and the assembly center axis of projection light machine have first angle, first angle is 4-8 degrees, which is conducive to realizing the miniaturization design requirement of temple in near-eye display device.

Description

Technical Field

[0001] This disclosure relates to a near-eye display device. Background Technology

[0002] In augmented reality (AR) display devices, diffractive waveguides and projection optical engines are two key optical components that play a crucial role in creating immersive AR experiences. Projection optical engines are used to project virtual images into the user's field of view, using lenses, mirrors, and other means to adjust and control the focus, brightness, and sharpness of the projected image.

[0003] Micro-LED projection optical engines are a new type of projection optical system based on self-emissive display technology. Compared with traditional projection optical engines, such as Digital Light Processing (DLP) optical engines, Liquid Crystal Display (LCD) or Liquid Crystal on Silicon (LCOS) optical engines, Micro-LED optical engines have advantages such as high brightness, high efficiency, and miniaturization. Summary of the Invention

[0004] This disclosure provides a near-eye display device. The near-eye display device includes: at least one projection optical engine, each projection optical engine including multiple displays, a prism group, and a lens structure. The prism group is located on the light-emitting side of the multiple displays, and the prism group includes multiple incident light surfaces and one exit light surface. Different incident light surfaces are configured to incident different colors of image light. The multiple displays are arranged in a one-to-one correspondence with the multiple incident light surfaces. The lens structure is located on the side where the exit light surface of the prism group is located. The prism group includes multiple prisms, and the lens structure includes at least one lens. The incident light surface corresponding to one of the multiple displays is passed through the assembly central axis of the projection optical engine. The center of the screen of the one display is offset by a specific distance relative to the assembly central axis so that the principal ray of the central field of view emitted from the projection optical engine has a first angle with the assembly central axis of the projection optical engine, the first angle being 4 to 8 degrees.

[0005] For example, according to an embodiment of this disclosure, the near-eye display device further includes: two waveguide lenses arranged along a first direction, the first direction being perpendicular to the assembly central axis. The at least one projection optical engine includes a plurality of projection optical engines, each waveguide lens corresponding to at least one of the plurality of projection optical engines; each waveguide lens includes a light-increasing region and a light-outcreasing region, the main ray of the central field of view enters the waveguide lens from the light-increasing region and is transmitted in the waveguide lens to the light-outcreasing region, the light emitted from the light-outcreasing region propagates to the human eye along a second direction, the normal of the waveguide lens has a second angle with the second direction, the first angle being twice the second angle; when the projection optical engine is configured to be in operation, the assembly central axis is parallel to the second direction.

[0006] For example, according to an embodiment of this disclosure, the human eye includes a left eye and a right eye. The light-in coupling region is closer to the two central planes of the left eye and the right eye than the light-out coupling region. The planes are perpendicular to the assembly central axis. Each waveguide lens corresponds to one of the eyeballs in the left eye and the right eye. The principal ray of the central field of view emitted by the projection optical engine corresponding to the same waveguide lens has a positional relationship with the eyeball: the principal ray of the central field of view is offset away from the eyeball relative to the assembly central axis.

[0007] For example, according to an embodiment of this disclosure, the waveguide lens is tilted toward the nasal wing below the human eye, and the main ray of the central field of view emitted by the projection optical engine is offset axially upward relative to the assembly center.

[0008] For example, according to an embodiment of this disclosure, the prism assembly includes multiple central symmetry axes perpendicular to the plurality of light-incident surfaces, and each display screen is traversed by a central symmetry axis perpendicular to its corresponding light-incident surface; the plurality of light-incident surfaces include a first light-incident surface disposed opposite to the light-outceasing surface, the first light-incident surface being traversed by the assembly central axis of the projection optical engine, the plurality of central symmetry axes including a first central symmetry axis perpendicular to the first light-incident surface and the light-outceasing surface, the first central symmetry axis being parallel to the assembly central axis; the plurality of display screens include a first display screen disposed corresponding to the first light-incident surface, the center of the first display screen being located on the side of the first central symmetry axis closer to the light coupling area.

[0009] For example, according to an embodiment of this disclosure, the plurality of light-incident surfaces further include a second light-incident surface and a third light-incident surface disposed opposite to each other, and the plurality of central symmetry axes further include a second central symmetry axis perpendicular to the second light-incident surface and the third light-incident surface, the second central symmetry axis being parallel to the first direction, and the plurality of display screens further include a second display screen and a third display screen, the second display screen being disposed corresponding to the second light-incident surface, the third display screen being disposed corresponding to the third light-incident surface, the second display screen being closer to the light coupling area than the third display screen; the center of the screen of the second display screen being farther away from the waveguide lens than the second central symmetry axis, and the center of the screen of the third display screen being closer to the waveguide lens than the second central symmetry axis.

[0010] For example, according to an embodiment of this disclosure, the prism assembly includes multiple central symmetry axes perpendicular to the plurality of light-incident surfaces, and each display screen is traversed by a central symmetry axis perpendicular to its corresponding light-incident surface; the plurality of light-incident surfaces include a first light-incident surface disposed opposite to the light-outceasing surface, the first light-incident surface being traversed by the assembly central axis of the projection optical engine, and the plurality of central symmetry axes including a first central symmetry axis perpendicular to the first light-incident surface and the light-outceasing surface; the plurality of display screens includes a first display screen disposed corresponding to the first light-incident surface, and the center of the screen of the first display screen is located below the first central symmetry axis.

[0011] For example, according to an embodiment of this disclosure, the plurality of light-incident surfaces further include a second light-incident surface and a third light-incident surface disposed opposite to each other, and the plurality of central symmetry axes further include a second central symmetry axis perpendicular to the second light-incident surface and the third light-incident surface, the second central symmetry axis being parallel to the first direction, the plurality of display screens further including a second display screen and a third display screen, the second display screen being disposed corresponding to the second light-incident surface, the third display screen being disposed corresponding to the third light-incident surface, the second display screen being closer to the light coupling area than the third display screen; the screen center of the second display screen and the screen center of the third display screen are both located below the second central symmetry axis.

[0012] For example, according to an embodiment of this disclosure, the near-eye display device further includes: two temples, respectively located on both sides of the two waveguide lenses, wherein the light-increasing region is closer to the corresponding temple than the light-outcreasing region. The plurality of projection optical engines are all located within the two temples, and the extending direction of each temple is parallel to the assembly central axis.

[0013] For example, according to embodiments of this disclosure, the first display screen, the second display screen, and the third display screen include a red display screen that emits red light, a green display screen that emits green light, and a blue display screen that emits blue light.

[0014] For example, according to an embodiment of this disclosure, the specific distance is 0.4 to 1 mm.

[0015] For example, according to an embodiment of this disclosure, the distance between the first central symmetry axis and the assembly central axis is less than the specific distance.

[0016] For example, according to an embodiment of this disclosure, the field of view of the projection optical engine is 25 degrees.

[0017] For example, according to an embodiment of this disclosure, each lens in the lens structure includes an aspherical surface.

[0018] For example, according to an embodiment of this disclosure, the near-eye display device is an augmented reality display device. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this disclosure and are not intended to limit this disclosure.

[0020] Figure 1A This is a schematic diagram of a near-eye display device for human viewing.

[0021] Figure 1B To be Figure 1A The diagram shows the assembly center axis of the projection optical engine in the near-eye display device being placed parallel to the Z-direction.

[0022] Figure 1C To be Figure 1B The diagram shows a projector tilted.

[0023] Figure 2 This is a partial structural schematic diagram of the projection optical engine in a near-eye display device provided according to an embodiment of the present disclosure.

[0024] Figure 3 Human vision includes Figure 2 A top view of the near-eye display device of the projection optical engine shown.

[0025] Figure 4 for Figure 3 The diagram shown illustrates the temples of the near-eye display device.

[0026] Figure 5 Human vision includes Figure 2 A side view of the near-eye display device of the projection optical engine shown.

[0027] Figure 6 for Figure 2 The modulation transfer function curve of the projector is shown.

[0028] Figure 7 for Figure 2 The diagram shows the longitudinal spherical aberration curve of the projector.

[0029] Figure 8 for Figure 2 The image astigmatism curve of the projector is shown.

[0030] Figure 9 for Figure 2 The diagram shows the distortion.

[0031] Figure 10 for Figure 2 A schematic diagram showing the deflection angle of the principal ray under different field of view angles of the projector. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Based on the described embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0033] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that an element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects.

[0034] Unless otherwise specified in the following embodiments of this disclosure, the quantity of a component is implied to mean that the component may be one or more, or can be understood as at least one. "At least one" means one or more, and "more" means at least two.

[0035] Currently, Micro-LED projection optical engines include monochromatic optical engines and full-color optical engines. Full-color optical engines can include red, green, and blue (RGB) three-color X-cube combined light (X-cube) full-color optical engines. Compared to monochromatic optical engines, X-cube full-color optical engines include an optical prism assembly, which is typically used to rotate and split the incident beam, dividing it into multiple output beams. This allows for beam splitting and orientation within a compact space, resulting in better optical performance and stability.

[0036] The X-cube full-color optical engine comprises a 0.4 cubic centimeter (CC) optical engine, primarily based on a 1GM3P optical structure. The full-color optical engine includes a display screen with a diagonal length of 0.13 inches, a resolution of 640*480, and each pixel size of approximately 4 micrometers, with a diagonal field of view of 30 degrees. In the aforementioned "1GM3P," GM refers to a glass lens, and P refers to a plastic lens; 1GM3P can refer to a four-element structure combining glass and plastic.

[0037] Figure 1A This is a schematic diagram of a near-eye display device for human viewing. Figure 1B To be Figure 1A The diagram shows the assembly center axis of the projection optical engine in the near-eye display device being placed parallel to the Z-direction. Figure 1C To be Figure 1B The diagram shows a projector tilted.

[0038] like Figure 1A As shown, the near-eye display device includes a projection optical engine 01 and a waveguide lens 02. The waveguide lens 02 includes a diffractive light waveguide. The projection optical engine 01 projects image light 04 onto the waveguide lens 02. After being guided in the waveguide lens 02, the image light 04 exits from the waveguide lens 02 and is emitted as image light 05. The image light 05 is vertically incident on the human eye 03 to form a virtual projected image. The human eye 03 can also observe the real scene through the waveguide lens 02. Therefore, this display device can be an augmented reality display device. Figure 1A The diagram schematically illustrates a waveguide lens in a near-eye display device viewed by a user's left eye. For example, the near-eye display device can be eyeglasses, including temples (not shown), and a projection optical engine 01 can be located within the temples.

[0039] like Figure 1B and Figure 1C As shown, the projection optical engine 01 includes a lens group 011 and a prism group 012. The lens group 011 is located on the light-emitting side of the prism group 012. The projection optical engine also includes multiple displays 013 located on the light-incident side of the prism group 012. For example, the optical axis of the lens group 011 is the assembly center axis 014 of the lens group 011 and the prism group 012. For example, the prism group 012 includes a central symmetry axis parallel to the Z direction, which passes through the center of the display screen. The aforementioned central symmetry axis passes through the geometric center of the prism group, and the aforementioned screen center can refer to the geometric center of the screen. The aforementioned central symmetry axis, optical axis, and assembly center axis can be a straight line.

[0040] like Figure 1BAs shown, when the central axis of the projection optical engine is placed parallel to the Z direction, taking the size of the cuboid enclosing the lens group 011 and the prism group 012 as an example without considering the display screen, lens part and packaging part, the dimension D1 of the cuboid in the Z direction is 11.536 mm, the dimension D2 of the cuboid in other directions perpendicular to the Z direction is 5.24 mm, and the volume of the cuboid is 0.317 cubic centimeters.

[0041] like Figure 1C As shown, when the projection optical engine is as Figure 1A When placed in the indicated orientation, taking the dimensions of a cuboid enclosing lens group 011 and prism group 012 as an example (excluding the display screen, lens assembly, and packaging), the dimension D10 of this cuboid in the Z direction is 12.153 mm, and the dimension D20 in other directions perpendicular to the Z direction, such as the X direction, is 6.794 mm. The volume of this cuboid is 0.561 cubic centimeters. Compared to... Figure 1B The projection optical engine shown Figure 1C The rotating projection optical engine shown significantly increases the volume.

[0042] like Figure 1A As shown, in order to fit the size of the user's brow bone and bridge of the nose, the glasses need to be tilted at a certain angle relative to the X direction and the Y direction perpendicular to the XZ plane when the user wears them.

[0043] For example, such as Figures 1A to 1C As shown, to adapt to the user's face shape, such as preventing the waveguide lens 02 from pressing on the user's nasal bridge, the two waveguide lenses 02 can be tilted to the sides of the eyes so that the angle between the two waveguide lenses 02 is less than 180 degrees. For example, if the angle of tilt of the waveguide lens 02 relative to the horizontal direction X is θ1, then in order for the image light ray 05 emitted from the waveguide lens 02 to propagate to the human eye 03 in a direction parallel to the vertical direction Z, the angle of the projection optical engine 01 relative to the Z direction needs to be adjusted to adjust the incident angle of the image light ray 04 incident on the waveguide lens 02. For example, if the incident angle of the light ray 04 is θ2, the angle of deflection of the light ray 04 relative to the Z direction is θ2 + θ3, where θ1, θ2, and θ3 satisfy the relationship: θ1 = θ2 = θ3. Therefore, the angle between the light ray 04 and the Z direction is twice the angle between the waveguide lens 02 and the X direction. For example, θ1 can be equal to 4 degrees.

[0044] For example, to adapt to the user's face shape, such as preventing the waveguide lens 02 from pressing against the user's brow bone, the two waveguide lenses 02 can be tilted towards the side closer to the bridge of the nose. For instance, the angle of tilt of the waveguide lens 02 relative to the Y direction perpendicular to the XZ plane is θ4 (not shown in the figure). In this case, to ensure that the light ray 05 emitted from the waveguide lens 02 propagates to the human eye 03 in a direction parallel to the vertical Z direction, the angle of the projection optical engine 01 relative to the Y direction needs to be adjusted to adjust the incident angle of the light ray 04 incident on the waveguide lens 02. For instance, the angle of deflection of the light ray 04 relative to the Y direction is θ5, where θ5 is twice θ4. For example, θ4 can be equal to 4 degrees.

[0045] In their research, the inventors of this application discovered that in order to accommodate the size of the brow bone and bridge of the nose when the user wears glasses, the waveguide lens needs to be deflected at a certain angle relative to the X and Y directions. At this time, in order to meet the viewing needs of the human eye, the projection optical engine also needs to be rotated. The space occupied by the rotated projection optical engine in the temple increases, making it difficult for the temple to meet the requirements of miniaturization.

[0046] This disclosure provides a near-eye display device. The near-eye display device includes at least one projection optical engine. Each projection optical engine includes multiple displays, a prism group, and a lens structure. The prism group is located on the light-emitting side of the multiple displays and includes multiple incident light surfaces and one exit light surface. Different incident light surfaces are configured to incident different colors of image light. The multiple displays are arranged in a one-to-one correspondence with the multiple incident light surfaces. The lens structure is located on the side where the exit light surface of the prism group is located. The prism group includes multiple prisms, and the lens structure includes at least one lens. The incident light surface corresponding to one of the multiple displays is passed through the assembly central axis of the projection optical engine. The center of the screen of the one display is offset by a specific distance relative to the assembly central axis so that the principal ray of the central field of view emitted from the projection optical engine has a first angle with the assembly central axis of the projection optical engine, the first angle being 4 to 8 degrees.

[0047] The near-eye display device disclosed herein achieves a first angle between the main ray emitted from the central field of view of the projector and the central axis of the projector by offsetting the center of the display screen relative to the assembly central axis of the projector by a specific distance. This allows the light to propagate to the human eye in a specific direction without rotating the projector, avoiding the problem of occupying a large space in the temple caused by rotating the projector. This is beneficial for achieving the miniaturization design requirements of the temple in the near-eye display device.

[0048] The near-eye display device provided in this disclosure is described below with reference to the accompanying drawings.

[0049] Figure 2 This is a partial structural schematic diagram of the projection optical engine in a near-eye display device provided according to an embodiment of the present disclosure.

[0050] like Figure 2 As shown, the near-eye display device includes at least one projection optical engine 10. Each projection optical engine 10 includes multiple displays 100, a prism group 200, and a lens structure 300. The prism group 200 is located on the light-emitting side of the multiple displays 100. The prism group 200 includes multiple light-incident surfaces and one light-emitting surface 240. Different light-incident surfaces are configured to incident different colors of image light. The multiple displays 100 are arranged in a one-to-one correspondence with the multiple light-incident surfaces. The lens structure 300 is located on the side where the light-emitting surface 240 of the prism group 200 is located. The prism group 200 includes multiple prisms, and the lens structure 300 includes at least one lens. For example, the lens structure 300 is located on the light-emitting side of the prism group 200.

[0051] For example, such as Figure 2 As shown, the light-incident surface and light-exit surface 240 included in the prism assembly 200 are both surfaces of the prisms in the prism assembly 200. Depending on whether light enters the surface from the display screen 100 or exits the surface after passing through the prism assembly 200, the corresponding surfaces are referred to as the light-incident surface and light-exit surface 240. For example, the prism assembly 200 may also include other surfaces that do not experience light entry or exit.

[0052] For example, such as Figure 2 As shown, each incident surface is configured to receive one color of image light, and different incident surfaces are configured to receive different colors of image light. The different colors of image light converge in the prism group 200 and exit from the same emitting surface 240. For example, each display screen 100 emits one color of image light, and different display screens 100 emit different colors of image light. The image light rays emitted from multiple display screens 100 are incident on their respective incident surfaces into the prism group 200, converge in the prism group 200, and exit from the same emitting surface 240 to the lens structure 300. The prism group 200 achieves the light combining effect of different colors of image light. The aforementioned principal rays include the principal rays among the different colors of image light.

[0053] For example, the prism group 200 can be a cubic light-combining prism group 200, which includes at least two prisms, or it can include four prisms, each of which is a right triangular prism. For example, a film layer group can be set between different prisms, such as a film layer group that can reflect the light from one of the multiple displays to the light-emitting surface 240, and transmit the light from at least one of the multiple displays.

[0054] For example, Figure 2 The lens structure 300 is schematically shown as a lens group, which includes four lenses, but is not limited to this. The lens group may include two lenses, three lenses or more lenses, or the lens structure 300 may include only one lens, which can be set according to product requirements.

[0055] like Figure 2As shown, the light-incident surface corresponding to one of the multiple displays 100 (such as the first display 110) is passed through the assembly center axis 301 of the projection optical engine 10. The screen center 1001 of the aforementioned display is offset by a specific distance D00 relative to the assembly center axis 301 so that the main ray of the central field of view emitted from the projection optical engine 10 has a first angle α1 with the assembly center axis 301, the first angle α1 being 4 to 8 degrees.

[0056] For example, such as Figure 2 As shown, the prism assembly 200 includes multiple central symmetry axes perpendicular to multiple light-incident surfaces. Each display screen 100 is passed through by a central symmetry axis perpendicular to its corresponding light-incident surface. The center of the screen of each display screen 100 is offset by a certain distance relative to the central symmetry axis passing through it, and the offset distance of the center of the screen of each display screen 100 relative to the central symmetry axis passing through it is less than the aforementioned specific distance.

[0057] The aforementioned central axis of symmetry can be an axis passing through the center of the prism assembly 200 and perpendicular to its surface. For example, the central axis of symmetry of the prism assembly 200 passing through the display screen 100 does not pass through the center of the display screen 100, that is, there is a certain distance between the central axis of symmetry and the center of the display screen 100, so that the principal ray of the image light emitted from the center of the display screen 100 does not coincide with the aforementioned central axis of symmetry. After passing through the lens structure 300, the principal ray has an angle greater than 0 degrees with both the aforementioned central axis of symmetry and the assembly central axis, so that the aperture surface of the aperture 1011 on the light-emitting side of the lens structure 300 is not perpendicular to the assembly central axis 301 of the projection optical engine 10, such as the aperture surface being tilted at a first angle relative to the assembly central axis 301. The aforementioned aperture surface can be a plane in the projection optical engine 10 that restricts the size, shape, and position of the light beam. This aperture surface is a virtual surface that allows light to pass through and is not an actual structural surface.

[0058] Figure 1A The center of the display screen in the projector 10 is traversed by the central axis of symmetry of the prism assembly 200 and the assembly center axis. The light rays emitted from the projector 10 coincide with the assembly center axis of the lens assembly within the projector 10. Therefore... Figure 1A The display screen in the projection optical engine 10 can be described as a non-off-axis design. Figure 1A The assembly center axis 301 of the projection optical engine 10 shown coincides with the optical axis of the lens in the optical engine. In the projection optical engine 10 provided in this application, the design of the screen center being offset relative to the assembly center axis can be referred to as the off-axis design of the screen. In the projection optical engine 10 provided in this application, the assembly center axis 301 does not coincide with the optical axis of the lens or the central axis of symmetry of the prism assembly.

[0059] The near-eye display device provided in this disclosure achieves a first angle between the main ray of the central field of view emitted from the projector 10 and the assembly center axis 301 of the projector 10 by offsetting the center of the display screen relative to the assembly center axis of the projector 10 by a specific distance. This allows the light to propagate to the human eye in a specific direction without rotating the projector 10, avoiding the problem of occupying a large space in the temple 40 caused by rotating the projector 10. This is beneficial to achieving the miniaturization design requirements of the temple 40 in the near-eye display device.

[0060] In the near-eye display device provided in this disclosure, by offsetting the center of the display screen relative to the assembly center axis by a certain distance, it is beneficial to reduce the size of the projection optical engine 10 and further realize the miniaturization design of the near-eye display device.

[0061] For example, such as Figure 2 As shown, each central axis of symmetry passes through the geometric center of the prism group 200, and different central axes of symmetry intersect at the geometric center of the prism group 200.

[0062] For example, such as Figure 2 As shown, the aforementioned "offset distance" can refer to the distance between a point on the screen through which the assembly center axis passes and the center of the screen.

[0063] For example, such as Figure 2 As shown, the first included angle α1 can be 4 degrees or 8 degrees. For example, the first included angle α1 can be 5 to 7 degrees, or 6 degrees, etc. The specific angles of the first included angle are not listed one by one in this embodiment of the disclosure, and the first included angle can be any angle between 4 and 8 degrees.

[0064] In some examples, such as Figure 2 As shown, the specific distance D00 mentioned above is 0.4 to 1 mm. For example, the offset distance of the screen center of different displays relative to the central axis of symmetry passing through them is different, and the difference in the offset distance of the screen center of different displays relative to the central axis of symmetry passing through them is small, such as not greater than 2 micrometers or not greater than half the size of a sub-pixel in the display. For example, the offset distance of other displays relative to the central axis of symmetry passing through them can be obtained based on the specific offset distance of the screen center of the first display relative to the assembly center axis and the offset distance relative to the central axis of symmetry passing through it. For example, the specific offset distance D00 mentioned above can be 0.4880 to 0.9841 mm. For example, the specific offset distance D00 mentioned above can be 0.5 mm, or 0.6 mm, or 0.7 mm, or 0.8 mm, or 0.9 mm, or 0.9241 mm. The specific values ​​of the specific offset distances mentioned above are not listed one by one in the embodiments of this disclosure, and can be any value between 0.4 and 1 mm.

[0065] By offsetting the center of the display screen by a certain distance relative to the corresponding central axis of symmetry, the main ray of the central field of view emitted from the projector 10 can have a first angle with the assembly central axis 301 of the projector 10, and the aperture surface of the aperture is tilted at the first angle, which is beneficial to meet the miniaturization design of near-eye display devices.

[0066] In some examples, such as Figure 2 As shown, each lens in lens structure 300 includes an aspherical surface.

[0067] By designing the lens in the lens structure 300 to use an aspherical surface without increasing the difficulty of optical design, and offsetting the center of the display screen relative to the assembly center axis by a specific distance, the off-axis design of the lens structure 300 in the projection optical engine 10 can be matched with the off-axis design of the display screen. Without increasing the design complexity of the lens structure 300, the principal ray of the central field of view emitted by the projection optical engine 10 is offset by a first angle relative to the assembly center axis 301, and the aperture surface of the aperture is tilted by a first angle. This simplifies the design of the projection optical engine 10 and facilitates its manufacture.

[0068] In some examples, such as Figure 2 As shown, the field of view of the projection engine 10 is 25 degrees. This field of view can be the angle along the diagonal of the display screen.

[0069] For example, such as Figure 2 As shown, the total optical path length (TTL) of the projection engine 10 can be 12.5 mm. The TTL is the distance between the aperture 1011 and the screen of the display. For example, the aperture diameter (or entrance pupil diameter) can be 3.7 mm. For example, the aperture of the projection engine 10 can be 1.7762.

[0070] For example, such as Figure 2 As shown, Figure 2 As shown, taking the overall component consisting of lens structure 300 and prism group 200 without considering the display screen, lens part, and packaging part as an example, the dimension D11 of this overall component in the Z direction is 12.1 mm, that is, the TTL is 12.1 mm. The overall component can be further reduced in size by edge cutting in the X direction and in the direction perpendicular to the XZ plane, such as dimension D21 being 4.9 mm. The volume of this overall component is 0.291 cubic centimeters, which is significantly smaller than that of the display screen, lens part, and packaging part. Figure 1C The volume of the projection optical engine is shown. The aforementioned edge-cutting process refers to removing the portions of the prism assembly 200 and lens assembly located outside the edge rays of the image light. Relative to... Figure 1CThe rotated projection optical engine shown in this embodiment of the present disclosure achieves a 4-8 degree angle between the principal ray emitted from the central field of view of the projection optical engine and the assembly central axis of the projection optical engine by moving the display screen relative to the prism assembly. This allows for better image viewing by the human eye while avoiding the increased size caused by rotating the optical engine. The aforementioned size corresponds to the size of the projection optical engine in which the principal ray emitted from the central field of view of the projection optical engine... Figure 3 The X direction shown and Figure 5 The projection engine shown is 8 degrees off-axis in the Y direction. For example, the principal ray emitted from the projection engine in the central field of view is only... Figure 3 When the X-direction is 8 degrees off the axis, the volume of the above-mentioned integral component is 0.362 cubic centimeters.

[0071] Figure 3 Human vision includes Figure 2 A top view of the near-eye display device of the projection optical engine shown.

[0072] In some examples, such as Figure 3 As shown, the near-eye display device further includes two waveguide lenses 20 arranged along a first direction perpendicular to the assembly central axis 301. At least one projection optical engine 10 includes a plurality of projection optical engines 10, with each waveguide lens 20 corresponding to at least one of the plurality of projection optical engines 10. Each waveguide lens 20 includes a light-introducing region 21 and a light-outtroducing region 22. The main ray of the central field of view emitted from the projection optical engine 10 enters the waveguide lens 20 from the light-introducing region 21 and is transmitted within the waveguide lens 20 to the light-outtroducing region 22. The light emitted from the light-outtroducing region 22 propagates to the human eye along a second direction. The normal of the waveguide lens 20 has a second angle α2 with the second direction, and the first angle α1 is twice the second angle α2. For example, the angle between the waveguide lens 20 and the first direction is the second angle, and / or, the angle between the waveguide lens 20 and a third direction perpendicular to the first and second directions is the second angle.

[0073] For example, the second included angle can be 2 to 4 degrees, such as 2 degrees, 3 degrees, or 4 degrees. This embodiment of the disclosure will not list specific values ​​for the second included angle; it can be any value between 2 and 4 degrees.

[0074] In some examples, such as Figure 3 As shown, when the projection optical engine 10 is configured to be in operation, the assembly center axis 301 of the projection optical engine 10 is parallel to the second direction. The aforementioned operating state of the projection optical engine 10 refers to the state in which the projection optical engine 10 projects an image onto the waveguide lens 20. At this time, the user is using the near-eye display device, such as eyeglasses, and the user is wearing the eyeglasses.

[0075] In the near-eye display device provided in this disclosure, by tilting the waveguide lens 20 at a second angle relative to the human eye to fit the brow bone and / or bridge of the nose, and adjusting the screen center of the display screen to be offset by a certain distance relative to the central axis of symmetry of the prism assembly 200, the light emitted from the projection optical engine 10 can be tilted at a first angle relative to the assembly central axis 301, so that the main light emitted from the waveguide lens 20 can enter the human eye vertically, while avoiding the rotation of the projection optical engine 10 relative to the vertical direction (i.e., the second direction) and the increase in the space occupied, thus realizing the miniaturization design of the near-eye display device.

[0076] For example, such as Figure 3 As shown, the first direction can be the X direction, and the second direction can be the Z direction, with the first direction perpendicular to the second direction. For example, the assembly center axis 301 extends along the Z direction.

[0077] In some examples, such as Figure 3 As shown, the near-eye display device is an augmented reality (AR) display device. For example, the near-eye display device is AR glasses.

[0078] For example, such as Figure 3 As shown, in each waveguide lens 20, a waveguide medium can be disposed between the light coupling region 21 and the light coupling region 22. At least one of the light coupling region 21 and the light coupling region 22 in the waveguide lens 20 includes a grating, so that the light emitted from the projection optical engine 10 is coupled into the waveguide medium through the grating, and / or, the light propagating by total internal reflection in the waveguide medium is coupled out to the human eye through the grating. For example, the grating may include a diffraction grating, a reflection grating, etc. For example, in addition to viewing the projected image through the waveguide lens 20, the human eye can also view the surrounding real environment through the waveguide lens 20, realizing the fusion effect of the virtual environment and the real environment.

[0079] For example, such as Figure 3 As shown, the human eye includes a left eye 31 and a right eye 32. One of the two waveguide lenses 20 corresponds to the left eye 31 and the other corresponds to the right eye 32, so that both eyes 32 can see the image.

[0080] For example, such as Figure 3 As shown, the two waveguide lenses 20 include two light-in coupling regions 21 and two light-out coupling regions 22, and the two light-out coupling regions 22 can be located between the two light-in coupling regions 21.

[0081] Figure 4 for Figure 3 The diagram shown illustrates the temples of the near-eye display device.

[0082] like Figure 4As shown, the near-eye display device also includes two temples 40, located on either side of the two waveguide lenses 20, with the light-increasing region 21 closer to the corresponding temple 40 than the light-outcreasing region 22. Multiple projection optical engines 10 are located within the two temples 40, and the extension direction of each temple 40 is parallel to the assembly central axis 301.

[0083] When the waveguide lens 20 is tilted relative to the human eye, adjusting the center of the display screen to be offset by a certain distance relative to the central axis of symmetry of the prism assembly 200 so that the assembly center axis 301 of the projection optical engine 10 is parallel to the extension direction of the temple 40 can avoid... Figure 1A The rotating projection optical engine 10, which occupies a large space in the temple 40, caused the temple 40 to have a large size. This paper proposes to achieve a miniaturized design for the temple 40.

[0084] For example, Figure 4 The diagram schematically illustrates the state of the temples 40 when the human eye is viewing the near-eye display device, with the temples positioned to the sides of the eye. For example, in other examples, when the near-eye display device is not being worn, the extension direction of the temples 40 may be along the second direction shown in the figure, or it may be along other directions. Regardless of which direction the temples 40 extend, the extension direction of the temples 40 is parallel to the assembly center axis 301 of the projection optical engine 10.

[0085] In some examples, such as Figure 3 As shown, the human eye includes a left eye 31 and a right eye 32. The light-increasing region 21 is closer to the two centers of the left eye 31 and right eye 32 on the plane 312, which is perpendicular to the assembly central axis 301, than the light-outcreasing region 22. Each waveguide lens 20 corresponds to one of the eyeballs in the left eye 31 and right eye 32. The principal ray of the central field of view emitted from the projection optical engine 10 corresponding to the same waveguide lens 20 has a positional relationship with the eyeball: the principal ray of the central field of view is offset away from the eyeball relative to the assembly central axis 301. For example, the light-outcreasing region 22 is tilted away from the human eye.

[0086] By adjusting the relative position of the center of the display screen and the central axis of symmetry of the prism assembly 200, the main ray of the central field of view can be shifted away from the eyeball by a first angle relative to the assembly central axis 301 and then incident into the waveguide lens 20. The light rays emitted through the waveguide lens 20 can be transmitted to the human eye in a specific direction, such as a direction perpendicular to the plane where the two centers of the left and right eyes are located.

[0087] For example, the two centers of the left eye 31 and the right eye 32 mentioned above can refer to the center of the sphere when the eyeball is approximated as a sphere, or they can be the optical center of the eyeball, such as the nodes of the eye's refractive system. The aforementioned plane is a virtual plane used to define the relative positional relationship between the light-incidence zone 21, the light-outcidence zone 22, and the human eye.

[0088] For example, with Figure 3 The arrow in the X direction points to the right. The image light emitted by the projection optical engine 10 located to the left of the left eye 31 is shifted to the left, and the image light emitted by the projection optical engine 10 located to the right of the right eye 32 is shifted to the right.

[0089] In some examples, such as Figure 3 As shown, the plurality of light-incident surfaces include a first light-incident surface 210 disposed opposite to the light-outcident surface 240, the first light-incident surface 210 being traversed by the assembly central axis 301 of the projection optical engine. The plurality of central symmetry axes include a first central symmetry axis 201 perpendicular to the first light-incident surface 210 and the light-outcident surface 240, the first central symmetry axis 201 being parallel to the assembly central axis 301 of the projection optical engine 10; the plurality of display screens include a first display screen 110 disposed corresponding to the first light-incident surface 210, the center of the screen of the first display screen 110 being located on the side of the first central symmetry axis 201 near the light coupling area 22.

[0090] In some examples, such as Figure 2 As shown, the distance between the first central symmetry axis 201 and the assembly central axis 301 is less than the aforementioned specific distance D00. For example, the screen center of the first display screen 110 is located on the side of the assembly central axis 301 closer to the light coupling area 22. For example, the first central symmetry axis 201 is located between the assembly central axis 301 and the screen center 1001 of the first display screen 110.

[0091] When the first central axis of symmetry of the prism assembly passes through the center of the screen of the first display screen, the first display screen is designed as a non-off-axis display screen. If the assembly central axis of the projection optical engine is parallel to the second direction, the light emitted from the projection optical engine will propagate along the second direction to the light coupling area, and after being guided in the waveguide lens to the light coupling area, it will be emitted. The emitted light will deflect away from the light coupling area, that is, it will not propagate along the second direction to the location of the human eye, resulting in the human eye being unable to see the projected image, or seeing an incomplete projected image, thus affecting the user experience.

[0092] In the near-eye display device provided in this disclosure, the assembly center axis 301 of the projection optical engine 10 is parallel to the second direction. By setting the screen center 1001 of the first display screen 110 to be located on the side of the first central axis of symmetry 201 close to the light coupling area 22, that is, setting the screen center 1001 of the first display screen 110 to be located on the side of the first central axis of symmetry 201 close to the human eye, the light emitted from the projection optical engine 10 can be deflected away from the human eye relative to the assembly center axis 301, thereby causing the light emitted from the waveguide lens 20 to propagate to the human eye along the second direction, improving the user's viewing experience.

[0093] For example, such as Figure 3As shown, the first light-incident surface 210 and the light-exit surface 240 are arranged parallel to each other. For example, the screen of the first display screen 110 is arranged parallel to the first light-incident surface 210, but it is not limited to this. A certain angle can also be set between the screen of the first display screen 110 and the first light-incident surface 210 as needed. For example, the first central axis of symmetry 201 passes through the center of the first light-incident surface 210 and the center of the light-exit surface 240, but does not pass through the center of the screen of the first display screen 110. For example, the lens structure 300 and the prism group 200 are assembled on the same assembly axis, which can be the assembly center axis 301 of the projection optical engine 10, and the first display screen 110 is off-axis relative to this assembly axis.

[0094] In some examples, such as Figure 3 As shown, the multiple light-incident surfaces also include a second light-incident surface 220 and a third light-incident surface 230 arranged opposite to each other. The multiple central symmetry axes also include a second central symmetry axis 202 perpendicular to the second light-incident surface 220 and the third light-incident surface 230, and the second central symmetry axis 202 is parallel to a first direction, such as the X direction. The multiple displays also include a second display screen 120 and a third display screen 130. The second display screen 120 is correspondingly arranged with the second light-incident surface 220, and the third display screen 130 is correspondingly arranged with the third light-incident surface 230. The second display screen 120 is closer to the light-exiting area 22 than the third display screen 130. The center of the screen of the second display screen 120 is further away from the waveguide lens 20 than the second central symmetry axis 202, and the center of the screen of the third display screen 130 is closer to the waveguide lens 20 than the second central symmetry axis 202.

[0095] For example, such as Figure 3 As shown, the second display screen 120 is located on the light-incident side of the second light-incident surface 220, and the third display screen 130 is located on the light-incident side of the third light-incident surface 230. For example, the second display screen 120 is closer to the human eye than the third display screen 130.

[0096] By shifting the center of the first display screen 110 towards the side closer to the human eye relative to the first central axis of symmetry 201, shifting the center of the second display screen 120 (which is closer to the human eye) away from the waveguide lens 20 relative to the second central axis of symmetry 202, and shifting the center of the third display screen 130 (which is farther from the human eye) towards the side closer to the waveguide lens 20 relative to the second central axis of symmetry 202, the main ray of the central field of view emitted from the projection optical engine 10 is shifted away from the human eye.

[0097] For example, such as Figure 3 As shown, the second display screen 120 and the third display screen 130 are translated in opposite directions relative to the second central axis of symmetry 202 to achieve that the main rays of the central field of view emitted from the projection optical engine 10 include converged rays of various colors.

[0098] For example, such as Figure 3 As shown, the second light-receiving surface 220 and the third light-receiving surface 230 are arranged parallel to each other. For example, the screen of the second display screen 120 is arranged parallel to the second light-receiving surface 220, and the screen of the third display screen 130 is arranged parallel to the third light-receiving surface 230. For example, the second central axis of symmetry 202 passes through the center of the second light-receiving surface 220 and the third light-receiving surface 230, but does not pass through the center of the screen of the second display screen 120 and the third display screen 130. For example, the first light-receiving surface 210 is perpendicular to the second light-receiving surface 220.

[0099] In some examples, such as Figure 3 As shown, the first display screen 110, the second display screen 120 and the third display screen 130 include a red display screen that emits red light, a green display screen that emits green light and a blue display screen that emits blue light.

[0100] For example, such as Figure 3 As shown, the first display screen 110 is a green display screen emitting green light, the second display screen 120 is a red display screen emitting red light, and the third display screen 130 is a blue display screen emitting blue light. However, this is not a limitation; for example, the colors of the second display screen 120 and the third display screen 130 can be interchanged. For example, the wavelength of red light can be any value between 571 and 750 nanometers, the wavelength of blue light can be any value between 350 and 495 nanometers, and the wavelength of green light can be any value between 496 and 570 nanometers.

[0101] Figure 5 Human vision includes Figure 2 A side view of the near-eye display device of the projection optical engine shown.

[0102] In some examples, such as Figure 5 As shown, the waveguide lens 20 is tilted toward the nose wing 33 below the human eye, and the main ray of the central field of view emitted by the projection optical engine 10 is offset upward relative to the assembly central axis 301.

[0103] By tilting the waveguide lens 20 towards the nose wing 33 below the user's eye, it can adapt to the user's brow bone and eliminate stray light. At the same time, it shifts the main ray of the central field of view emitted from the projection optical engine 10 upward relative to the assembly central axis 301, allowing the light emitted from the waveguide lens 20 to propagate towards the user's eye in a vertical direction (i.e., the second direction). This further avoids the increased space occupied by rotating the projection optical engine 10 relative to the vertical direction, achieving a miniaturized design for the near-eye display device. In addition, tilting the waveguide lens 20 towards the nose wing 33 below the user's eye can prevent the light emitted from the projection optical engine 10 from being reflected back into the projection optical engine 10, thereby eliminating stray light.

[0104] For example, such as Figure 5 As shown, with the arrow pointing in the Y direction pointing upwards, the nasal wing 33 is located below the human eye, and the lower part of the waveguide lens 20 is tilted towards the side closer to the nasal wing 33, that is, the upper part of the waveguide lens 20 is tilted away from the brow bone.

[0105] In some examples, such as Figure 3 and Figure 5 As shown, the plurality of light-incident surfaces include a first light-incident surface 210 disposed opposite to the light-outceasing surface 240, and the plurality of central symmetry axes include a first central symmetry axis 201 perpendicular to the first light-incident surface 210 and the light-outceasing surface 240; the plurality of displays include a first display screen 110 disposed corresponding to the first light-incident surface 210, and the center of the screen of the first display screen 110 is located below the first central symmetry axis 201. For example, the center of the screen of the first display screen 110 is located below the assembly central axis 301.

[0106] By shifting the center of the first display screen 110 downwards relative to the first central axis of symmetry 201, light rays emitted from the projection engine 10 are deflected upwards and then incident on the waveguide lens 20. Light rays emitted from the waveguide lens 20 then propagate vertically towards the human eye. Shifting the center of the first display screen 110 downwards avoids the problem of the projection engine 10 occupying a large space due to rotation, which is beneficial for further miniaturizing the temple 40.

[0107] For example, such as Figure 5 As shown, the center of the first display screen 110 is farther from the human eye than the first central axis of symmetry 201.

[0108] In some examples, such as Figure 3 and Figure 5 As shown, the multiple light-incident surfaces also include a second light-incident surface 220 and a third light-incident surface 230 arranged opposite to each other. The multiple central symmetry axes also include a second central symmetry axis 202 perpendicular to the second light-incident surface 220 and the third light-incident surface 230. The second central symmetry axis 202 is parallel to the first direction. The multiple display screens 100 also include a second display screen 120 and a third display screen 130. The second display screen 120 is arranged corresponding to the second light-incident surface 220, and the third display screen 130 is arranged corresponding to the third light-incident surface 230. The second display screen 120 is closer to the light-exiting area 22 than the third display screen 130. The center of the screen of the second display screen 120 and the center of the screen of the third display screen 130 are both located below the second central symmetry axis 202.

[0109] By shifting the center of the first display screen 110 downward relative to the first central axis of symmetry 201, and simultaneously shifting the center of the second display screen 120 and the center of the third display screen 130 downward relative to the second central axis of symmetry 202, the main ray of the central field of view emitted from the projection optical engine 10 is shifted upward relative to the second central axis of symmetry 202.

[0110] For example, such as Figure 5 As shown, the center of the screen of the second display 120 and the center of the screen of the third display 130 are both farther away from the human eye than the second central axis of symmetry 202.

[0111] For example, such as Figure 3 and Figure 5 As shown, the waveguide lens 20 rotates at a second angle α20 in the Y direction. The angle α20 of rotation in the X direction and the angle α20 of rotation in the Y direction can be the same or different. For example, Figure 5 The angle at which the light rays emitted from the projection optical engine 10 are deflected relative to the Z direction is the first angle α10. Figure 5 The angle α10 of the light rays emitted from the projection optical engine 10 relative to the Z direction is shown to be... Figure 3 The angle α1 of the light rays emitted from the projection optical engine 10 relative to the Z direction can be the same or different.

[0112] Figure 6 for Figure 2 The diagram shows the modulation transfer function (MTF) curve of the projection optical engine. Figure 7 for Figure 2 The diagram shows the longitudinal spherical aberration curve of the projector. Figure 8 for Figure 2 The image astigmatism curve of the projector is shown. Figure 9 for Figure 2 The diagram shows the distortion. Figure 10 for Figure 2 A schematic diagram showing the deflection angle of the principal ray under different field of view angles of the projector.

[0113] Figures 6 to 10 The curve shown is Figure 2 The curve obtained by optical simulation when the first angle of the projection optical engine 10 is 8 degrees.

[0114] For example, Figure 6The diagram shows meridian 502 and sagitta 501 in the diffraction limit, meridian 503 and sagitta 504 of the projection engine 10 in an 8-degree field of view, meridian 505 and sagitta 506 in a -4.5-degree field of view, meridian 507 and sagitta 508 in a 20.5-degree field of view, meridian 509 and sagitta 510 in a 14-degree field of view, and meridian 511 and sagitta 512 in a 2-degree field of view. Solid lines represent meridians, and dashed lines represent sagittas.

[0115] For example, the modulation transfer function value mentioned above can also be called resolution, which is the ability to distinguish details of the original object being photographed. It is a physical quantity that can be used to describe the ability of a microphotography system to reproduce the fine details of the original object being photographed.

[0116] The modulation transfer function (MTF) curve can comprehensively reflect the imaging quality of an optical system. The smoother the curve shape and the higher the MTF value, the better the imaging quality of the optical system. Figure 6 The modulation transfer function (MTF) curves at a cutoff frequency of 125 line pairs / mm (lp / mm) are shown, with the figure illustrating the MTF curves for multiple field-of-view rays. For example... Figure 6 As shown, the overall modulation transfer function curve is smooth, and the modulation transfer function value under a 20.5-degree field of view can reach above 0.3.

[0117] For example, the meridians and sagittas mentioned above can all be green light (e.g., with a center wavelength of 550 nanometers).

[0118] For example, such as Figure 7 As shown, the vertical axis represents the normalized field of view, and 0 on the horizontal axis represents the ideal focal point along the assembly center axis. The absolute values ​​of the offsets of curves 601, 602, and 603 relative to the ideal focal point are all less than 0.02 mm, indicating relatively small spherical aberration. Curve 601 represents the longitudinal spherical aberration curve for red light with a center wavelength of 630 nm, curve 602 represents the longitudinal spherical aberration curve for green light with a center wavelength of 530 nm, and curve 603 represents the longitudinal spherical aberration curve for blue light with a center wavelength of 460 nm.

[0119] Figure 8 and Figure 9 The astigmatism curve and distortion curve of green light (e.g., center wavelength of 530 nm) are shown respectively.

[0120] For example, such as Figure 8 As shown, 0 in the horizontal and vertical axes represents the ideal focal point along the assembly center axis. The absolute values ​​of the offsets of the astigmatism curves 701 in the meridional direction and 702 in the sagittal direction relative to the ideal focal point are both no greater than 0.02. Therefore, the astigmatism is relatively small.

[0121] For example, such as Figure 9 As shown, distortion is a parameter in an optical system and one of the important factors limiting the accuracy of optical measurements. It is the degree of distortion of the image formed by an optical system relative to the object itself. Figure 9 The distortion level of the projection optical engine is shown. At a field of view of 20.5 degrees, the relative distortion of the projection optical engine is no less than -1%.

[0122] For example, such as Figure 10 As shown, in multiple fields of view with angles ranging from -4 degrees to 20.5 degrees, the absolute value of the angle between the principal ray and the screen normal of each field of view does not exceed 5 degrees, resulting in good light collection. A smaller angle between the principal ray and the screen normal helps reduce the difficulty of designing the reflective surface coating in the prism assembly.

[0123] Therefore, it can be seen that the projection optical engine provided in this disclosure adopts an off-axis design and has good optical performance, such as high resolution, low distortion and low astigmatism.

[0124] The following points need to be explained:

[0125] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure, and other structures can be referred to the general design.

[0126] (2) Where there is no conflict, features of the same embodiment and different embodiments of this disclosure may be combined with each other.

[0127] The above description is merely an exemplary embodiment of this disclosure and is not intended to limit the scope of protection of this disclosure, which is determined by the appended claims.

Claims

1. A near-eye display device, comprising: At least one projection engine is provided, each projection engine comprising multiple displays, a prism assembly, and a lens structure. The prism assembly is located on the light-emitting side of the multiple displays, and includes multiple incident surfaces and one exit surface. Different incident surfaces are configured to receive different colors of image light. The multiple displays are arranged in a one-to-one correspondence with the multiple incident surfaces. The lens structure is located on the side where the exit surface of the prism assembly is located. The prism assembly includes multiple prisms, and the lens structure includes at least one lens. In this configuration, the light-incident surface corresponding to one of the plurality of display screens is passed through the assembly center axis of the projection optical engine. The center of the screen of the one display screen is offset by a specific distance relative to the assembly center axis so that the main ray of the central field of view emitted from the projection optical engine has a first angle with the assembly center axis of the projection optical engine, the first angle being 4 to 8 degrees.

2. The near-eye display device according to claim 1, further comprising: Two waveguide lenses are arranged along a first direction, which is perpendicular to the assembly center axis. Wherein, the at least one projection optical engine includes a plurality of projection optical engines, and each waveguide lens corresponds to at least one of the plurality of projection optical engines; Each waveguide lens includes a light inlet area and a light outlet area. The main ray of the central field of view enters the waveguide lens from the light inlet area and is transmitted to the light outlet area in the waveguide lens. The light rays emitted from the light outlet area propagate to the human eye along a second direction. The normal of the waveguide lens has a second angle with the second direction, and the first angle is twice the second angle. When the projection optical engine is configured to be in operation, the assembly center axis is parallel to the second direction.

3. The near-eye display device according to claim 2, wherein, The human eye includes a left eye and a right eye. The light inlet area is closer to the two central planes of the left and right eyes than the light outlet area. The planes are perpendicular to the assembly central axis. Each waveguide lens corresponds to one of the eyeballs in the left and right eyes. The principal ray of the central field of view emitted by the projection optical engine corresponding to the same waveguide lens has a positional relationship with the eyeball: the principal ray of the central field of view is offset away from the eyeball relative to the assembly central axis.

4. The near-eye display device according to claim 2, wherein, The waveguide lens is tilted toward the nose below the human eye, and the main ray of the central field of view emitted by the projection optical engine is offset upward relative to the assembly center axis.

5. The near-eye display device according to claim 3, wherein, The prism assembly includes multiple central symmetry axes perpendicular to the plurality of light-incident surfaces, and each display screen is passed through by a central symmetry axis perpendicular to its corresponding light-incident surface; The plurality of light-incident surfaces include a first light-incident surface disposed opposite to the light-outcident surface, the first light-incident surface being passed through the assembly center axis of the projection optical engine, and the plurality of central symmetry axes including a first central symmetry axis perpendicular to the first light-incident surface and the light-outcident surface, the first central symmetry axis being parallel to the assembly center axis; The plurality of displays include a first display screen disposed corresponding to the first light-incident surface, wherein the center of the screen of the first display screen is located on the side of the first central axis of symmetry near the light-out region.

6. The near-eye display device according to claim 5, wherein, The plurality of light-incident surfaces further include a second light-incident surface and a third light-incident surface disposed opposite to each other, and the plurality of central symmetry axes further include a second central symmetry axis perpendicular to the second light-incident surface and the third light-incident surface, the second central symmetry axis being parallel to the first direction. The plurality of displays also includes a second display and a third display, wherein the second display is disposed corresponding to the second light-incident surface, the third display is disposed corresponding to the third light-incident surface, and the second display is closer to the light-outceasing area than the third display. The center of the second display screen is farther away from the waveguide lens than the second central axis of symmetry, and the center of the third display screen is closer to the waveguide lens than the second central axis of symmetry.

7. The near-eye display device according to claim 4, wherein, The prism assembly includes multiple central symmetry axes perpendicular to the plurality of light-incident surfaces, and each display screen is passed through by a central symmetry axis perpendicular to its corresponding light-incident surface; The plurality of light-incident surfaces include a first light-incident surface disposed opposite to the light-outcident surface, the first light-incident surface being passed through the assembly center axis of the projection optical engine, and the plurality of central symmetry axes including a first central symmetry axis perpendicular to the first light-incident surface and the light-outcident surface; The plurality of displays include a first display screen disposed corresponding to the first light-receiving surface, wherein the center of the screen of the first display screen is located below the first central axis of symmetry.

8. The near-eye display device according to claim 7, wherein, The plurality of light-incident surfaces further include a second light-incident surface and a third light-incident surface disposed opposite to each other, and the plurality of central symmetry axes further include a second central symmetry axis perpendicular to the second light-incident surface and the third light-incident surface, the second central symmetry axis being parallel to the first direction. The plurality of displays also includes a second display and a third display, wherein the second display is disposed corresponding to the second light-incident surface, the third display is disposed corresponding to the third light-incident surface, and the second display is closer to the light-outceasing area than the third display. The center of the second display screen and the center of the third display screen are both located below the second central axis of symmetry.

9. The near-eye display device according to any one of claims 2-8, further comprising: The two temples are located on either side of the two waveguide lenses, with the light-in coupling area closer to the corresponding temple than the light-out coupling area. The plurality of projection optical engines are all located in the two temples, and the extension direction of each temple is parallel to the assembly center axis.

10. The near-eye display device according to claim 6 or 8, wherein, The first display screen, the second display screen, and the third display screen include a red display screen that emits red light, a green display screen that emits green light, and a blue display screen that emits blue light.

11. The near-eye display device according to any one of claims 1-8, wherein, The specific distance is 0.4 to 1 mm.

12. The near-eye display device according to claim 5, wherein, The distance between the first central symmetry axis and the assembly center axis is less than the specific distance.

13. The near-eye display device according to any one of claims 1-8, wherein, The field of view of the projection optical engine is 25 degrees.

14. The near-eye display device according to any one of claims 1-8, wherein, Each lens in the lens structure includes an aspherical surface.

15. The near-eye display device according to any one of claims 1-8, wherein, The near-eye display device is an augmented reality display device.

Images