Near-to-eye display system based on short-focus turn-back light path

Abstract

The invention discloses a near-to-eye display system based on a short-focus turn-back light path. The near-to-eye display system comprises a curved-surface display screen, a first lens and a second lens which are sequentially arranged from the environment side to the human eye side. Wherein the curved display screen is a transparent display screen; the first lens and the second lens do not have perspective focal power to natural light; the polarizing film systems are arranged on the surfaces of the first lens and the second lens, so that light emitted by a display screen passes through the first lens in a transmission manner, is reflected and amplified twice by the second lens and the first lens in sequence, and finally enters human eyes for imaging; ambient light transmits through the display screen, the first lens and the second lens and enters human eyes for imaging. The near-to-eye display system is realized based on a short-focus turn-back light path and a transparent curved-surface display screen, and can realize augmented reality display with a large field angle.

Description

Technical Field

[0001] This invention relates to a near-eye display system based on a short-focal-length refracting optical path, belonging to the field of near-eye display devices. Background Technology

[0002] Virtual reality (VR) and augmented reality (AR) near-eye displays have revolutionized human-computer interaction, bringing new possibilities for convenience in production, daily life, and entertainment. Because AR technology can perceive the surrounding real environment through video or light while displaying virtual images, it has a wider range of real-world applications. To achieve the integration of virtual images with the real environment, various optical solutions exist, including birdbaths, waveguides, and freeform prisms.

[0003] Slim design and wide field of view have always been the goals of near-eye display devices. Using Fresnel lenses, pancake lenses, and birdbath solutions can reduce the size of near-eye display devices to some extent, but a wide field of view remains a major challenge. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a near-eye display system based on a short-focal-length refracting optical path.

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0006] A near-eye display system based on a short-focal-length refracting optical path, the near-eye display system comprising, arranged sequentially from the environment side to the human eye side:

[0007] A curved display screen, wherein the curved display screen is a transparent display screen;

[0008] A first lens is positioned close to the curved display screen; the two surfaces of the first lens have the same shape and do not have transmittance for natural light; and a partial reflective film is provided on the surface of the first lens.

[0009] The second lens is positioned away from the curved display screen; the two surfaces of the second lens have the same shape and do not have transmittance for natural light; and a first quarter-wave plate and a reflective polarizer are disposed on the surface of the second lens, with the reflective polarizer being closer to the human eye than the first quarter-wave plate.

[0010] The curvature of the curved display screen is opposite to that of the first lens; the light emitted from the curved display screen is transmitted through the first lens, and after being amplified twice by the second lens and the first lens, it finally enters the human eye to form an image.

[0011] Ambient light is transmitted through the curved display screen, the first lens, and the second lens, and then enters the human eye to form an image.

[0012] Preferably, the curved display screen convexes towards the human eye.

[0013] Preferably, the first lens convexes toward the curved display screen, and the second lens is concave or convex toward the curved display screen.

[0014] Preferably, the two surfaces of the first lens have a first radius of curvature, and the two surfaces of the second lens have a second radius of curvature;

[0015] Both the first lens and the second lens are convex toward the curved display screen, and the first radius of curvature and the second radius of curvature have the same value; or, the first lens is convex toward the curved display screen, and the second lens is concave toward the curved display screen, and the absolute values ​​of the first radius of curvature and the second radius of curvature are different.

[0016] Preferably, the near-eye display system further includes a third lens positioned close to the human eye, the two surfaces of the third lens having the same surface shape and having no transmittance to natural light; the first lens convex to the curved display screen, the second lens and the third lens both concave to the curved display screen, and the first lens, the second lens and the third lens having the same surface shape parameters.

[0017] Preferably, the third lens, the reflective polarizer, the first quarter-wave plate, and the second lens are cemented together in sequence.

[0018] Preferably, at least one lens is constructed using a microlens array consisting of multiple microlenses, wherein the front and rear surfaces of the microlenses have the same surface shape, do not have transmittance for natural light, and the radii of curvature of the front and rear surfaces of the microlenses differ from the radii of curvature of the at least one lens within the range of 1 μm.

[0019] According to one embodiment of the present invention, the fast axis direction of the first quarter-wave plate is at 45° to the optical transmission axis of the reflective polarizer;

[0020] A second quarter-wave plate and an absorptive polarizer are disposed between the curved display screen and the first lens. The optical transmission axis of the absorptive polarizer is at an angle of 20° to 27° to the fast axis of the second quarter-wave plate, and the fast axis directions of the first quarter-wave plate and the second quarter-wave plate are the same.

[0021] According to another embodiment of the present invention, the fast axis direction of the first quarter-wave plate is at 45° to the optical transmission axis of the reflective polarizer;

[0022] A second quarter-wave plate and an absorptive polarizer are disposed between the curved display screen and the first lens. The optical transmission axis of the absorptive polarizer is at 45° to the fast axis of the second quarter-wave plate, and the fast axis directions of the first quarter-wave plate and the second quarter-wave plate are the same.

[0023] The first quarter-wave plate and the reflective polarizer partially cover the surface of the first lens, and / or the second quarter-wave plate and the absorptive polarizer partially cover the light-transmitting aperture of the display screen.

[0024] Preferably, the distance between the curved display screen and the first lens is adjustable.

[0025] The near-eye display system provided by this invention is based on a short-focal-length refracting optical path and a transparent curved display screen, which can expand the field of view while reducing the size. Based on the use of a transparent curved display screen, by adjusting the setting of the polarization film system, it can simultaneously achieve the immersive effect of magnifying the screen image and the function of sensing the external environment. Attached Figure Description

[0026] Figure 1A This is a schematic diagram of Embodiment 1 of the present invention, which uses a curved display screen and two lenses to form a short-focal-length refracting optical path;

[0027] Figure 1B This is a schematic diagram of a short-focal-length refracting optical path constructed using a flat panel display and two lenses;

[0028] Figure 2 This is a schematic diagram of Embodiment 2 of the present invention, which uses two lenses to form a short-focal-length refracting optical path;

[0029] Figure 3 This is a schematic diagram of a short-focal-length refracting optical path constructed using three lenses in Embodiment 3 of the present invention;

[0030] Figure 4 This is a schematic diagram of the polarizing film system partially covering the lens surface in Embodiment 4 of the present invention;

[0031] Figure 5 This is a schematic diagram of Embodiment 5 of the present invention, which describes an embodiment of constructing a lens using a microlens array in a short focal length refraction optical path. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0034] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0035] The near-eye display system provided by this invention constructs a short-focal-length reflective optical path based on at least two lenses without transmittance, a polarizing optical element, and a transparent curved display screen. Augmented reality display is achieved by using the transparent curved display screen and at least two lenses without transmittance. The curved display screen, the first lens, and the second lens are arranged sequentially from the environment side towards the human eye side.

[0036] Curved displays can be displays whose light-emitting surface is bent into a fixed arc, or flexible screens that are maintained at a certain arc. Based on eye habits, curved displays are cylindrical in shape and have a certain radius of curvature in the horizontal direction perpendicular to the viewing axis. Transparent curved displays refer to displays with a certain transmittance to ambient light, not specifically displays with 100% transmittance. For example, existing OLED transparent screens can achieve a transmittance of about 85% to ambient light.

[0037] A lens is a lens whose front and rear surfaces are both curved and have the same surface shape. It has no transmittance power for natural light, and the reflectance power of each surface is not zero. The surface parameters of the two lenses can be the same or different, and the thicknesses of the two lenses can be the same or different. By setting a partial reflective film on the surface of the first lens, and setting a first quarter-wave plate and a reflective polarizer (the reflective polarizer is placed closer to the human eye than the first quarter-wave plate) on the surface of the second lens, a short-focal-length refracted optical path is constructed.

[0038] The light emitted from the curved display screen passes through the aforementioned short-focal-length reflective optical path and is directed to the human eye to form a virtual image; ambient light passes through the curved display screen, the first lens, and the second lens in sequence to form a real image in the human eye. The aforementioned display screen, the first lens, and the second lens have no optical focal length for directly transmitted ambient light.

[0039] In this near-eye display system, the curvature of the curved display screen is opposite to that of the first lens closest to the screen. Using a curved display screen expands the field of view of the virtual image, providing a better visual experience for the user. The transparent curved display screen and the transparent, non-photofocal lens allow the user to simultaneously observe the external environment. The light emitted from the curved display screen is reflected between the two lenses, effectively reducing the size of the glasses and improving their wearability. This invention uses a short-focal-length pancake optical path with a curved display screen to achieve a field of view of at least 80°.

[0040] In the aforementioned near-eye display system, a transparent curved display screen (e.g., an OLED transparent screen) is used for display. To convert the emitted light into circularly polarized light, an absorptive linear polarizer and a second quarter-wave plate are placed between the first lens and the curved display screen. Since the polarization states of ambient light and image light are simultaneously affected by the absorptive linear polarizer and the second quarter-wave plate, to achieve simultaneous imaging of ambient light and image light, the angle between the optical transmission axis of the absorptive polarizer and the fast axis of the second quarter-wave plate, or the coverage area of ​​the first quarter-wave plate and the reflective polarizer, can be adjusted. Different implementation methods are described below.

[0041] Example 1:

[0042] like Figure 1AThe device shown includes a curved display screen 101 and two lenses 102 and 103 with no transmittance. An absorptive polarizer and a quarter-wave plate are disposed on the surface of the first lens 102 near the curved display screen 101 or on the surface of the curved display screen 101. The absorptive polarizer and the quarter-wave plate are arranged sequentially along the direction of light propagation. The optical axis of the absorptive polarizer and the fast axis (or slow axis) of the quarter-wave plate are at an angle of 20° to 27° to provide elliptically polarized light to the first curved optical lens 102. The first lens 102 has a uniform thickness, no transmittance, and a semi-reflective and semi-transparent film 106 is coated on one side of its surface. A reflective polarizer 108 and a quarter-wave plate 107 are coated on one side of the second lens 103. The reflective polarizer 108 is closer to the human eye, and the optical axis of the reflective polarizer 108 is at a 45° angle to the fast axis of the quarter-wave plate 105. The fast axis of the quarter-wave plate 107 is the same as that of the quarter-wave plate 105. Preferably, a semi-reflective and semi-transparent film 106 is deposited on the surface of the first lens 102 facing the second lens 103 (the surface close to the human eye), and a reflective polarizer 108 and a quarter-wave plate 107 are disposed on the surface of the second lens 103 facing the first magnifying lens 102, thereby reducing reflected stray light in the short focal length refracted optical path.

[0043] In the aforementioned optical system, the light emitted from the curved display screen 101 becomes elliptically polarized light (e.g., right-handed elliptically polarized light) after passing through an absorptive polarizer and a quarter-wave plate. After being refracted by the first lens 102, it is incident on the right side surface of the second lens 103. After passing through the quarter-wave plate 107, it is transformed into first linearly polarized light. At this time, the fast axis (or slow axis) of the quarter-wave plate forms an angle of 20 to 27° with the axis of the linearly polarized light. The linearly polarized light is transmitted and reflected at the reflective polarizer 108. The transmitted light (e.g., p-line polarized light) is directly refracted by the second lens 103 and imaged onto the human eye. The reflected light is linearly polarized (e.g., s-polarized light). After passing through the quarter-wave plate 107, it becomes first circularly polarized light (e.g., left-handed circularly polarized light). The light then re-enters the right side of the first lens 102 and is reflected by the semi-reflective film there, becoming second circularly polarized light (e.g., right-handed circularly polarized light). After passing through the quarter-wave plate 107, it becomes second linearly polarized light (e.g., p-polarized light), which is transmitted through the reflective polarizer 108 and refracted by the second lens 103 to form an image on the human eye. Similarly, the optical path of ambient light is the same as that of the curved display screen. The energy ratio of the transmitted light to the reflected light is 1:3 to 1:2.

[0044] Although the optical path of the curved display screen is exactly the same as that of the ambient light, the image on the curved display screen can be presented as an image that can be recognized by the human eye after being magnified by the short-focus reflection system based on the focal length setting of the short-focus reflection system. As for the ambient light, the brightness of the image formed by its transmitted light path is higher than that of the image formed by the reflection system, and the size and clarity of the image are more suitable for human eye to distinguish, so the human eye can clearly observe the environmental image.

[0045] In the above technical solution, the first lens 102 and the second lens 103 are combined in different ways with curved display screens 101 of different radii of curvature. The curved display screen 101 uses a flexible screen, which can change its curvature according to different structures, so that each image unit obtains a continuous, clear and complete image after passing through the short-focal-length reflex optical system.

[0046] In such Figure 1A In the embodiment shown, the display screen 101 uses a curved display screen that convexes towards the human eye. Both lenses 102 and 103 convex towards the display screen. The two lenses 102 and 103 have the same radius of curvature. The focal length of the short-focal-length refracting optical path formed by the two lenses 102 and 103 is 15mm to 20mm, and the field of view is as high as 100°.

[0047] Table 1 shows the surface parameters used in this embodiment. Surfaces 1 to 7 are, in order, the lens surface (eye-side surface of the second lens 103) near the human eye to the surface of the display screen 101. Surface 7 is the surface of the curved display screen 101. The first lens 102 and the second lens 103 use aspherical lenses with the same parameters. With such a lens combination, a single lens can achieve a thickness of 1.21 mm and bend towards the human eye to form a crescent shape. The axial thickness of the virtual image imaging device is no more than 15 mm, which reduces the volume and thickness in the user's line of sight, and is beneficial to the miniaturization and weight reduction of the device.

[0048] Table 1. Surface parameters of the optical system using a curved display screen and a combination of concave eye-side lenses.

[0049]

[0050] In contrast, the present invention also provides an optical system using a flat panel display 101' and two lenses 102' and 103', wherein, under the premise of using lenses with similar parameters, using the same polarizing film system, and keeping the system thickness and volume close, the field of view of the optical system is reduced from 100° to 50°.

[0051] Table 2 Surface parameters of the optical system using a combination of a flat panel display and a biconcave eye-side lens.

[0052]

[0053] For pancake display systems, when using a flat screen, the larger the field of view, the greater the aberrations of the edge rays, thus limiting the field of view (FOV) of the optical system. When the screen becomes curved, with the curvature of the curved screen opposite to that of the first lens, the curved screen bends towards the imaging position where aberrations are smaller, thereby expanding the field of view of the optical system. In other words, for systems aiming for a large FOV, the aberrations at the edges of the field of view are greater than those at the center. Curved screens are better suited for designs with a large FOV; as the FOV increases, the radius of curvature of the curved screen decreases.

[0054] Example 2

[0055] like Figure 2 In the illustrated embodiment, the near-eye display optical system comprises a curved display screen 201 and two lenses. The curved display screen 201 is convex to the human eye, the first lens 202 is concave to the human eye, and the second lens 203 is convex to the human eye. The radius of curvature of the second lens 203 is greater than that of the first lens 202. In this embodiment, the polarizing film system disposed on the surface of the curved display screen 201 and on the surfaces of the first lens 202 and the second lens 203 is the same as in Embodiment 1. The imaging optical path of the display screen and the imaging optical path of the ambient light are also the same as in Embodiment 1, and will not be described again here.

[0056] As shown in Table 3, the surface parameters are arranged from 1 to 7, from the lens surface closest to the human eye to the display screen surface. Surface 7 is the surface of the curved display screen 201. The first lens 202 and the second lens 203 are aspherical lenses. The parameters of the first lens 202 and the second lens 203 are different. With this lens combination, a single lens can reach a thickness of 1 mm and bend towards the human eye to form a crescent shape. The field of view of the virtual image imaging device can also reach 100°, and the axial thickness is no more than 11 mm, which further reduces the thickness and volume in the direction of the user's line of sight.

[0057] Table 3 Surface parameters of an optical system using a curved display screen and a combination of convex and concave eye-side lenses.

[0058]

[0059] Example 3:

[0060] like Figure 3 The illustrated embodiment, in Figure 2 Based on this, an auxiliary lens is added near the human eye, and the optical parameters of the three lenses in the system are made completely consistent, all of which are lenses with zero transmittance.

[0061] Specifically, such as Figure 3As shown, the near-eye display system, from the environmental side to the human eye side, consists of: a curved display screen 301, an absorptive polarizer (POL), a first quarter-wave plate, a first lens 302, a second lens 303, a second quarter-wave plate 307, a reflective polarizer (RP) 308, and a third lens 309. The outer side of the first lens 302 is coated with a beam-splitting film layer 306. The first lens 302, second lens 303, and third lens 309 use the same optical parameters. The first lens 302 convexes towards the display screen, while the second lens 303 and third lens 309 are concave towards the display screen. This design achieves a small volume and large field of view (FOV) using only one lens specification paired with a flexible curved screen, reducing lens molding costs. Its surface parameters are as follows... Figure 4 As shown, surfaces 1 to 8 represent the lens surface closest to the human eye and the display screen surface, respectively. The three lenses utilize quadratic curved surfaces, with each individual lens being only 0.8 mm thick, resulting in an overall system thickness of less than 10 mm.

[0062] Table 4. Surface parameters of an optical system using a curved display screen and three identical lenses.

[0063]

[0064] Example 4

[0065] The near-eye display system provided in this embodiment includes a curved display screen and two lenses with no optical power. The parameters of the curved screen and the lenses can use the design parameters in Embodiments 1 and 2.

[0066] In this embodiment, an absorptive polarizer and a second quarter-wave plate are disposed on the surface of the first lens (102, 202) near the curved display screen (101, 202) or on the surface of the curved display screen (101, 202). The absorptive polarizer is disposed between the curved display screen and the second quarter-wave plate. The optical axis of the absorptive polarizer and the fast axis (or slow axis) of the quarter-wave plate are at 45° to provide circularly polarized light to the first curved optical lens.

[0067] The first lens has a uniform thickness, no transmittance, and a semi-reflective, semi-transparent film coated on either side. The second lens has a uniform thickness, no transmittance, and a reflective polarizer and a first quarter-wave plate coated on either side. The reflective polarizer is closer to the human eye, and its transmission axis is at 45° to the fast axis of the first quarter-wave plate. The fast axes of the first and second quarter-wave plates are the same. In this embodiment, the partially reflective film completely covers the entire surface of the first lens, the absorptive polarizer and the second quarter-wave plate partially cover the surface of the first lens (102, 202), and / or the first quarter-wave plate and the reflective polarizer only cover a local area of ​​the second lens (103, 203), with the remaining areas uncoated. Figure 4 As shown, the black blocks represent the areas on the surface of the first or second lens that are partially covered, while the remaining open areas are used for ambient light transmission and imaging. This image is only used to illustrate partial coating and is not intended to limit the specific implementation of partial coating.

[0068] In this optical system, light emitted from the curved display screen becomes circularly polarized (e.g., right-handed circularly polarized) after passing through an absorptive polarizer and a second quarter-wave plate. After refraction by the first lens, it enters the right side surface of the second lens. Passing through the first quarter-wave plate, it transforms into first linearly polarized light. At this point, the axis of this linearly polarized light forms a 90° angle with the transmission direction of the reflective polarizer. This linearly polarized light is reflected back at the reflective polarizer and transmitted through the uncoated area, forming an image in the human eye. The reflected light is linearly polarized (e.g., s-polarized), which, after passing through the first quarter-wave plate, becomes first circularly polarized (e.g., right-handed circularly polarized). This light again enters the right side of the first lens and is reflected by a semi-reflective film, transforming into second circularly polarized light (e.g., left-handed circularly polarized). After passing through the first quarter-wave plate, it becomes second linearly polarized (e.g., p-polarized), transmitted through the reflective polarizer, and refracted by the second lens, forming an image in the human eye. Similarly, the optical path of ambient light is the same as that of the curved display screen.

[0069] In this embodiment, since the polarization states of the light from the curved display screen and the ambient light are the same, the optical paths of the curved display screen and the ambient light are completely identical. Similarly, based on the focal length setting of the short-focus refraction system, the image on the curved display screen, after being magnified by the short-focus refraction system, can be presented as an image recognizable by the human eye. The brightness of the image formed by the transmitted light path of the ambient light is higher than that formed by the refraction system, and the size and clarity of the image are more suitable for human eye resolution, so the human eye can clearly observe the ambient image. In this embodiment, in the area of ​​the second lens surface covered by the first quarter-wave plate and the polarizing reflective film, the image light undergoes refraction and a change in polarization state, ultimately entering the human eye to form an image; in the area not covered by the second lens surface, ambient light directly transmits and forms an image. The ratio of the image light to the ambient light's brightness depends on the area ratio of the coated area on the second lens surface; by adjusting the coated area of ​​the second lens, this ratio can be adjusted.

[0070] Example 5

[0071] This invention can also use microlens arrays to construct the aforementioned multiple lenses, thereby combining them with a curved display screen to achieve augmented reality display. On one hand, by setting a curved display screen to match a microlens array group (including at least two microlens arrays to achieve a short focal length refraction optical path), the exit pupil displays a continuous image. On the other hand, by selecting a transparent curved display screen, real light from the external environment directly enters the human eye, achieving an augmented reality effect.

[0072] like Figure 5 The near-eye display optical system shown includes a curved display screen 401, a first microlens array 402, and a second microlens array 403. An absorptive polarizer 404 and a quarter-wave plate 405 are attached to the surface of the first microlens array 402 near the curved display screen or to the emitting surface of the curved display screen 401. The absorptive polarizer 404 is positioned between the curved display screen 401 and the quarter-wave plate 405. The area covered by the absorptive polarizer 404 and the quarter-wave plate 405 is smaller than the area of ​​each sub-lens, preferably covering only the central area, with no coating on the edge areas. A partial reflective film 406 is coated on either side surface of the first microlens array 402. Only a partial area of ​​the right side of the second microlens array 403 is covered by a quarter-wave plate 407 and a reflective polarizer 408; the area covered by the quarter-wave plate 407 and the reflective polarizer 408 is smaller than the area of ​​each sub-lens, preferably covering only the central area, with no coating on the edge areas.

[0073] The overall structure of the above system is similar to that shown in Figure 1, where, as Figure 5As shown, the curved display screen 401 convexes towards the human eye, while the overall configurations of the two microlens arrays 402 and 403 are concave towards the human eye. The first microlens is concave towards the human eye, with the radii of curvature of its front and rear surfaces in the same direction. A microlens array consisting of multiple first microlenses arranged along a first curved surface constitutes the first lens 402. The first curved surface is concave towards the human eye, and the difference between the radii of curvature of the front and rear surfaces of the first microlens and the first curved surface is within 1 μm. The second microlens is concave towards the human eye, with the radii of curvature of its front and rear surfaces in the same direction. A microlens array consisting of multiple second microlenses arranged along a second curved surface constitutes the second lens 403. The second curved surface is concave towards the human eye, and the difference between the radii of curvature of the front and rear surfaces of the second microlens and the second curved surface is within 1 μm. The first and second microlenses can have the same radius of curvature and thickness. The radii of curvature of the first and second curved surfaces can be the same or different. The optical aperture of each microlens is in the range of 10 μm to 1 mm.

[0074] When the first quarter-wave plate and the reflective polarizer partially cover the surface of the second microlens, the second quarter-wave plate and the absorptive polarizer partially or completely cover the surface of the first microlens near the display screen. When the first quarter-wave plate and the reflective polarizer completely cover the surface of the second microlens, the second quarter-wave plate and the absorptive polarizer partially cover the surface of the second microlens.

[0075] In this embodiment, the propagation methods of image light and ambient light are similar to those in Embodiment 4, and will not be repeated here.

[0076] The aforementioned near-eye display system based on microlens arrays and the pancake principle provides a large field of view while reusing spatial depth and reducing device size. Under the premise of compressing the product thickness to less than 10.5mm, the field of view can reach 140°.

[0077] Furthermore, this embodiment employs a short-focal-length pancake optical path, using a microlens array instead of a lens. Each sub-lens array has a quarter-wave plate and an absorptive linear polarizing film attached to it. The film area is smaller than the optical aperture of each sub-lens array. The boundary area between each sub-lens array does not control the polarization state of the light, allowing ambient light to pass through this area and directly enter the human eye without being reflected.

[0078] In summary, the near-eye display system provided by this invention uses a transparent curved display screen, coupled with multiple lenses with zero optical power, allowing ambient light to enter the human eye for imaging without affecting the normal image formation on the screen. By moving the distance between the curved display screen and the two lenses, the diopter of the entire optical system corresponding to the human eye can be adjusted to meet the needs of different users.

[0079] The foregoing has provided a detailed description of the near-eye display system based on a short-focal-length refracting optical path provided by this invention. Any obvious modifications made by those skilled in the art without departing from the essence of this invention will constitute an infringement of the patent rights of this invention and will incur corresponding legal liability.

Claims

1. A near-eye display system based on a short-focal-length refracting optical path, characterized in that, The near-eye display system comprises, arranged sequentially from the environmental side to the human eye side: A curved display screen, wherein the curved display screen is a transparent display screen; A first lens is positioned close to the curved display screen; the two surfaces of the first lens have the same shape and do not have transmittance for natural light; and a partial reflective film is provided on the surface of the first lens. The second lens is positioned away from the curved display screen; the two surfaces of the second lens have the same shape and do not have transmittance for natural light; and a first quarter-wave plate and a reflective polarizer are disposed on the surface of the second lens, with the reflective polarizer being closer to the human eye than the first quarter-wave plate. The curvature of the curved display screen is opposite to that of the first lens; the light emitted from the curved display screen is transmitted through the first lens, and after being amplified twice by the second lens and the first lens, it finally enters the human eye to form an image. Ambient light is transmitted through the curved display screen, the first lens, and the second lens, and then enters the human eye to form an image.

2. The near-eye display system as described in claim 1, characterized in that: The curved display screen bulges towards the human eye.

3. The near-eye display system as described in claim 2, characterized in that: The first lens convexes toward the curved display screen, and the second lens is concave or convex toward the curved display screen.

4. The near-eye display system as described in claim 2, characterized in that: The two surfaces of the first lens have a first radius of curvature, and the two surfaces of the second lens have a second radius of curvature; Both the first lens and the second lens are convex toward the curved display screen, and the first radius of curvature and the second radius of curvature have the same value; or, the first lens is convex toward the curved display screen, and the second lens is concave toward the curved display screen, and the absolute values ​​of the first radius of curvature and the second radius of curvature are different.

5. The near-eye display system as described in claim 2, characterized in that: The near-eye display system also includes a third lens positioned close to the human eye. The two surfaces of the third lens have the same surface shape and do not have transmittance for natural light. The first lens is convex to the curved display screen, and the second and third lenses are both concave to the curved display screen. The first lens, the second lens, and the third lens have the same surface shape parameters.

6. The near-eye display system as described in claim 5, characterized in that: The third lens, the reflective polarizer, the first quarter-wave plate, and the second lens are cemented together in sequence.

7. The near-eye display system as described in any one of claims 3-6, characterized in that: At least one lens is constructed using a microlens array consisting of multiple microlenses, wherein the front and rear surfaces of the microlenses have the same surface shape, do not have transmittance for natural light, and the radii of curvature of the front and rear surfaces of the microlenses differ from the radii of curvature of the at least one lens within the range of 1 μm.

8. The near-eye display system as described in any one of claims 3-6, characterized in that: The fast axis of the first quarter-wave plate forms a 45° angle with the optical transmission axis of the reflective polarizer; A second quarter-wave plate and an absorptive polarizer are disposed between the curved display screen and the first lens. The optical axis of the absorptive polarizer is at an angle of 20° to 27° to the fast axis of the second quarter-wave plate, and the fast axis directions of the first quarter-wave plate and the second quarter-wave plate are the same.

9. The near-eye display system as described in any one of claims 3-6, characterized in that: The fast axis of the first quarter-wave plate forms a 45° angle with the optical transmission axis of the reflective polarizer; A second quarter-wave plate and an absorptive polarizer are disposed between the curved display screen and the first lens. The optical transmission axis of the absorptive polarizer is at 45° to the fast axis of the second quarter-wave plate, and the fast axis directions of the first quarter-wave plate and the second quarter-wave plate are the same. The first quarter-wave plate and the reflective polarizer partially cover the surface of the first lens, and / or the second quarter-wave plate and the absorptive polarizer partially cover the light-transmitting aperture of the display screen.

10. The near-eye display system as described in claim 1, characterized in that: The distance between the curved display screen and the first lens is adjustable.

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