Near-eye display optical system and near-eye display device

Abstract

The application provides a near-eye display optical system and a near-eye display device. The near-eye display optical system is composed of a folding optical element of an image source, a first prism, a first lens and a reflecting film, at least uses the reflection principle of light, increases the reflection times to realize multiple folding light paths, so that the near-eye display optical system has a longer light path in a smaller volume, and can balance a large field of view, a light and thin volume and good imaging quality. By limiting the absolute value of the ratio f / R1 of the focal length f and the first curvature radius R1 in the range of 0.3 to 0.4, a larger field of view can be stably realized under the premise of ensuring that the thickness of the near-eye display optical system is small, and the imaging clarity of the center and the edge is ensured, and the near-eye display device is suitable for high requirements of portability and immersion.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more particularly to a near-eye display optical system and a near-eye display device. Background Technology

[0002] In recent years, augmented reality technology has been widely used in consumer electronics fields such as movie watching and entertainment. Among them, the Birdbath optical solution, due to its relatively simple structure and good image quality, has become the near-eye display optical system used in mainstream movie-watching AR glasses on the market. However, the Birdbath optical solution is generally quite thick, and its field of view is directly related to the screen size and volume. A large field of view Birdbath optical solution requires a larger screen, and at the same time, the size of the optical solution will also increase, making it impossible to meet the requirements of lightweight design.

[0003] Therefore, there is an urgent need to provide a near-eye display optical system that can balance a large field of view, a thin and light size, and good image quality. Summary of the Invention

[0004] This application provides a near-eye display optical system and a near-eye display device that can balance a large field of view, a thin and light size, and good imaging quality.

[0005] This application provides a near-eye display optical system, including: Image source; A first prism has a first surface, a second surface, and a third surface. The first surface of the first prism is disposed close to the image source, and the second surface of the first prism is disposed close to the eye box of the near-eye display optical system. A first lens has a fourth surface and a fifth surface disposed opposite to each other along its own thickness direction. The fourth surface is disposed close to the third surface, and the fifth surface is a curved surface with a first radius of curvature R1. A reflective film is disposed on one side near the fifth surface of the first lens; The light emitted from the image source is incident on the first surface of the first prism. After at least one total internal reflection occurs in the first prism, the light exits from the third surface of the first prism to the first lens. The light reflected by the reflective film enters the first prism again from the third surface and then exits from the second surface to the eye box of the near-eye display optical system. The near-eye display optical system satisfies the following: the absolute value of the ratio f / R1 of the system focal length f of the near-eye display optical system to the first radius of curvature R1 satisfies: 0.3≤|f / R1|≤0.4.

[0006] In some embodiments, the absolute value of the ratio f / R1 of the system focal length f of the near-eye display optical system to the first radius of curvature R1 satisfies: 0.31≤|f / R1|≤0.36.

[0007] In some embodiments, the light emitted from the image source is incident on the first surface of the first prism, and after being reflected by the third surface of the first prism and the second surface of the first prism, it propagates again to the third surface of the first prism and exits from the third surface of the first prism.

[0008] In some embodiments, the first surface has a second radius of curvature R2, wherein the second radius of curvature R2≥0.

[0009] In some embodiments, the near-eye display optical system further includes a second prism having a sixth surface and a seventh surface. The sixth surface of the second prism is disposed close to the eye box of the near-eye display optical system, and the seventh surface of the second prism is disposed close to the second surface of the first prism. Light reflected by the reflective film exits the first prism from the second surface, passes through the seventh surface and the sixth surface of the second prism, and then exits the eye box of the near-eye display optical system.

[0010] In some embodiments, the near-eye display optical system further includes a polarizing reflective film and a quarter-wave plate, the polarizing reflective film being disposed between a second surface of the first prism and a seventh surface of the second prism, and the quarter-wave plate being disposed between the first lens and a third surface of the first prism.

[0011] In some embodiments, the fourth surface of the first lens is spaced apart from the third surface of the first prism, and the quarter-wave plate is disposed on the fourth surface of the first lens.

[0012] In some embodiments, the near-eye display optical system further includes a first linear polarizer disposed on the light-emitting side of the image source.

[0013] In some embodiments, the near-eye display optical system further includes a second linear polarizer disposed on the sixth surface of the second prism.

[0014] In some embodiments, the near-eye display optical system further includes a second lens located on the side of the first lens away from the first prism.

[0015] In some embodiments, the second lens has an eighth surface and a ninth surface disposed opposite to each other along its own thickness direction, the eighth surface and the fifth surface being mutually compensating, and the ninth surface being disposed parallel to the fourth surface.

[0016] In some embodiments, the near-eye display optical system further includes a third lens disposed between the image source and the first prism, wherein light emitted from the image source passes through the third lens and then enters the first surface of the first prism.

[0017] In some embodiments, the third lens has a tenth surface and an eleventh surface opposite each other along its own thickness direction. The tenth surface is disposed close to the image source, and the eleventh surface is disposed close to the first surface of the first prism. The tenth surface is a plane, and the eleventh surface is a curved surface.

[0018] In some embodiments, the first surface is a curved surface with a second radius of curvature R2; the eleventh surface has a third radius of curvature R3, and the ratio of the second radius of curvature R2 to the third radius of curvature R3 is R2 / R3 < 0.

[0019] The center thickness of the third lens ranges from 1.5 mm to 2.5 mm.

[0020] In some embodiments, the center thickness of the first lens ranges from 2.5 mm to 4.5 mm.

[0021] In some embodiments, the field of view of the near-eye display optical system is 55 to 70 degrees.

[0022] In some embodiments, the absolute value of f / R1 satisfies: 0.34≤|f / R1|≤0.4; the field of view of the near-eye display optical system is 65 degrees to 70 degrees.

[0023] In some embodiments, the thickness of the near-eye display optical system is 11 mm to 13 mm.

[0024] This application embodiment also provides a near-eye display device, including: Framework structure; As described above, the near-eye display optical system is mounted on the frame structure.

[0025] The near-eye display optical system and near-eye display device provided in this application embodiment utilize a folded optical element composed of an image source, a first prism, a first lens, and a reflective film. By leveraging the principle of light reflection, the system increases the number of reflections to achieve multiple folds in the optical path, resulting in a longer optical path within a smaller volume. This balances a large field of view, a slim profile, and good image quality. Furthermore, by limiting the absolute value of the ratio f / R1 (the system focal length f to the first radius of curvature R1) to within the range of 0.3 to 0.4, a stable large field of view of 55 to 70 degrees can be achieved while maintaining a small thickness of the near-eye display optical system. Simultaneously, image sharpness at the center and edges is guaranteed, making it suitable for near-eye display devices with high requirements for portability and immersion. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of a first structure of a near-eye display optical system provided in an embodiment of this application.

[0028] Figure 2 This is a schematic diagram of a second structure of a near-eye display optical system provided in an embodiment of this application.

[0029] Figure 3 This is a schematic diagram of a third structure of the near-eye display optical system provided in an embodiment of this application.

[0030] Figure 4 This is a first schematic diagram of the modulation transfer function curve of a near-eye display optical system provided in an embodiment of this application.

[0031] Figure 5 This is a first schematic diagram of the field curvature and astigmatism curves of a near-eye display optical system provided in an embodiment of this application.

[0032] Figure 6 This is a second schematic diagram of the modulation transfer function curve of the near-eye display optical system provided in the embodiments of this application.

[0033] Figure 7 This is a second schematic diagram of the field curvature and astigmatism curves of a near-eye display optical system provided in an embodiment of this application. Detailed Implementation

[0034] The technical solutions of the embodiments of this application 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 this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0035] Near-eye display devices, also known as head-mounted displays (HMDs) or simply head-mounted displays, can be used to achieve augmented reality (AR), virtual reality (VR), and mixed reality (MR) effects. Near-eye display devices can take the form of glasses, helmets, or other similar devices.

[0036] The near-eye display optical system is one of the core components of a near-eye display device. It is responsible for generating the light rays needed to display the image and, through the regulation of these rays, ensuring that the light is ultimately projected into the user's eyes so that the user can see the displayed content. Therefore, to ensure a good user experience, it is necessary to design the near-eye display optical system appropriately.

[0037] Please see Figure 1 , Figure 1 This is a schematic diagram of a first structure of a near-eye display optical system provided in an embodiment of this application.

[0038] This application provides a near-eye display optical system 100. It should be noted that the near-eye display optical system 100 is a system composed of a variety of optical elements arranged in a certain order. For the near-eye display optical system 100, the optical axis is the line connecting the optical centers of each optical element in the near-eye display optical system 100 in sequence, and each optical element is arranged along the optical axis.

[0039] The near-eye display optical system 100 may include an image source 101, a first prism 102, a first lens 103, and a reflective film 104. The first prism 102 has a first surface 1021, a second surface 1022, and a third surface 1023. The first surface 1021 of the first prism 102 is disposed near the image source 101, and the second surface 1022 of the first prism 102 is disposed near the eyepiece of the near-eye display optical system 100. The first lens 103 has a fourth surface 1031 and a fifth surface 1032 disposed opposite to each other along its own thickness direction. The fourth surface 1031 is disposed near the third surface 1023, and the fifth surface 1032 is curved and has a first radius of curvature R1. The reflective film 104 is disposed on the side near the fifth surface 1032 of the first lens 103.

[0040] Examples of image source 101 include, but are not limited to: organic light-emitting diode (OLED) image sources, micro organic light-emitting diode (MicroOLED) image sources, liquid crystal (LCD) image sources, liquid crystal on silicon (LCOS) image sources, microelectromechanical system (MEMS) image sources, and digital micromirror devices (DMDs). For example, image source 101 can be a Micro OLED display.

[0041] The first prism 102 can be used to extend the optical path of the near-eye display optical system 100. The first surface 1021 of the first prism 102 can be opposite to the image source 101. The first surface 1021 and the second surface 1022 of the first prism 102 are both located on the side of the third surface 1023 of the first prism 102 closer to the eye box. The first surface 1021 and the second surface 1022 can intersect, the first surface 1021 and the third surface 1023 can intersect, and the second surface 1022 and the third surface 1023 can also intersect.

[0042] The eye box refers to the area where the human eye can clearly and completely view the displayed image. The eye box of the near-eye display optical system 100 can also be called the Eye Box (EB).

[0043] The first lens 103 can be used to correct field curvature and provide optical power to achieve a larger field of view. The fourth surface 1031 of the first lens 103 can be opposite to the third surface 1023 of the first prism 102. The fourth surface 1031 can be a plane. The fifth surface 1032 can be a curved surface, such as a spherical, aspherical, or freeform surface. A reflective film 104 can be provided on the fifth surface 1032 of the first lens 103 by means of coating or bonding. In other embodiments, the reflective film 104 is spaced apart from the fifth surface 1032.

[0044] The reflective film 104 can be used for total or partial reflection of light. If the reflective film 104 is used for partial reflection of light, it can be a semi-transparent and semi-reflective film.

[0045] The light propagation path is as follows: the light emitted from the image source 101 enters from the first surface 1021 of the first prism 102, undergoes at least one total internal reflection inside the first prism 102, exits from the third surface 1023 of the first prism 102 and enters the first lens 103, then propagates to the reflective film 104, and after being reflected by the reflective film 104, the light enters the first prism 102 again from the third surface 1023, and then exits from the second surface 1022 to the eye box of the near-eye display optical system 100.

[0046] In some optional embodiments, light enters from the first surface 1021 of the first prism 102, undergoes total internal reflection, exits from the third surface 1023, reaches the first lens 103, and then reaches the reflective film 104. For example... Figure 1 The reflective film 104 changes the direction of light propagation, for example, reflecting light that is propagating horizontally to the right into light that is propagating horizontally to the left, so that the deflected light passes through the first prism 102 again and enters the eye box.

[0047] Therefore, the near-eye display optical system 100 provided in this application embodiment can effectively guide the light emitted by the image source 101 into the eye box through the coordinated work of the image source 101, the first prism 102, the first lens 103 and the reflective film 104, so that the human eye can see the display content presented by the image source 101, and meet the normal display needs of near-eye display devices, such as supporting user movie viewing and other application scenarios.

[0048] The near-eye display optical system 100 satisfies the following condition: the absolute value of the ratio f / R1 of the system focal length f of the near-eye display optical system 100 to the first radius of curvature R1 of the fifth surface 1032 of the first lens 103 satisfies: 0.3 ≤ |f / R1| ≤ 0.4. For example, |f / R1| can be 0.30, 0.31, 0.32, 0.34, 0.36, 0.37, 0.40, etc., and will not be listed here. In this case, the field of view (FOV) of the optical system 100 is 55 degrees to 70 degrees. Furthermore, the absolute value of the ratio f / R1 of the system focal length f of the near-eye display optical system 100 to the first radius of curvature R1 satisfies: 0.31 ≤ |f / R1| ≤ 0.36.

[0049] Furthermore, when the absolute value of f / R1 satisfies: 0.34≤|f / R1|≤0.4, the field of view (FOV) of the optical system 100 is 65 to 70 degrees.

[0050] It is worth noting that the radius of curvature is a geometric quantity that describes the degree of curvature of a surface. The smaller its absolute value, the more curved the surface; the larger its absolute value, the flatter the surface. f can be a positive value, and R1 can be a positive or negative value. In this formula, the absolute value of the f / R1 ratio is used to characterize the proportional relationship between the system's focal length and the bending strength.

[0051] |f / R1| is a dimensionless ratio. If this ratio is too large or too small, it will affect the imaging performance and volumetric efficiency of the near-eye display optical system 100.

[0052] The first lens 103 is an element in the near-eye display optical system 100 that corrects field curvature and provides the main optical power. R1 controls the curvature of the first lens 103, thereby affecting the light refraction capability and aberration contribution.

[0053] The system focal length f determines the imaging ratio and observation range of the near-eye display optical system 100. When the ratio of the system focal length f to the radius of curvature R1 of the fifth surface of the first lens is within the above range, it is possible to effectively balance the spherical aberration and astigmatism generated by the first lens while keeping the total system length (TTL) at around 12 mm, and at the same time provide a reasonable incident angle for other aberration correction elements (such as the third lens), thereby achieving the optimal image quality to volume ratio as a whole.

[0054] For a given value f, if f / R1 is too small (ratio < 0.3), it means that the first lens 103 tends to be flat and the optical power is insufficient. It is necessary to rely on other elements such as prisms or additional lenses to provide greater deflection. This often requires increasing the axial length or lateral dimension of the near-eye display optical system 100, thereby increasing the volume of the near-eye display optical system 100. If f / R1 is too large (ratio > 0.4), the first lens 103 is too curved relative to the system focal length. Although it can shorten the back focal distance, it will introduce severe spherical aberration, coma, and astigmatism, resulting in a sharp decline in the image quality of the edge field of view. The actual usable FOV is actually limited.

[0055] This application limits the range of the ratio between the system focal length and the radius of curvature of the first lens, so that the near-eye display optical system 100 can stably achieve a large field of view of 55 to 70 degrees with a small thickness, while ensuring the image clarity of the center and the edge. This makes the near-eye display optical system 100 suitable for near-eye display devices with high requirements for portability and immersion.

[0056] In some optional embodiments disclosed in this application, the light emitted by the image source 101 can be incident on the first surface 1021 of the first prism 102, and then, after being reflected by the third surface 1023 of the first prism 102 and the second surface 1022 of the first prism 102, propagate again to the third surface 1023 of the first prism 102, and exit from the third surface 1023 of the first prism 102.

[0057] In an optional example, such as Figure 1As shown, the light emitted by the image source 101 may include light ray b1. After entering the first prism 102 through the first surface 1021, light ray b1 propagates to the third surface 1023 and undergoes total internal reflection there, turning towards the direction of the second surface 1022; after reaching the second surface 1022, it is reflected and finally exits from the third surface 1023 to the first lens 103.

[0058] As another example, such as Figure 2 As shown, Figure 2 This is a schematic diagram of a second structure of the near-eye display optical system provided in an embodiment of this application. The light emitted by the image source 101 may include multiple light rays such as b2, b3, and b4. These light rays have a similar propagation path to light ray b1: each light ray first undergoes total internal reflection at the third surface 1023, then reflection at the second surface 1022, and then exits through the third surface 1023 to the first lens 103.

[0059] It should be noted that total internal reflection refers to the phenomenon where light rays traveling from an optically denser medium to an optically less dense medium undergo only reflection and no further refraction. The critical angle for total internal reflection depends on the refractive indices of the optically denser and optically less dense media.

[0060] Through the above optical path design, the light emitted from the image source 101 enters the first prism 102 and undergoes only one total internal reflection and one reflection. This not only extends the optical path of the near-eye display optical system 100, but also avoids the problems of increased volume of the first prism 102 and excessive light divergence caused by too many reflections and total internal reflections.

[0061] In some embodiments, after the light emitted from the image source 101 enters the first prism 102 from the first surface 1021, the number of total internal reflections it undergoes within the first prism 102 before exiting from the third surface 1023 of the first prism 102 to the first lens 103 may not be limited to one, nor may the number of reflections it undergoes within the first prism 102 be limited to one. For example, the light may undergo a first total internal reflection at the third surface 1023 of the first prism 102, followed by a first reflection at the second surface 1022 of the first prism 102; then, the light may propagate again to the third surface 1023 and undergo a second total internal reflection, then reach the second surface 1022 and undergo a second reflection, and finally exit from the third surface 1023 of the first prism 102 to the first lens 103.

[0062] In some embodiments disclosed in this application, the first surface 1021 of the first prism 102 has a second radius of curvature R2, where R2 ≥ 0. When R2 = 0, the first surface is planar; when R2 > 0, the first surface 1021 is curved. For example, when R2 > 0, the first surface 1021 can be spherical, aspherical, or freeform, and its radius of curvature can be optimized according to aberration correction requirements, so that the first prism 102 not only undertakes the function of optical path reversal but also actively participates in the deflection of the imaging beam, thereby sharing the optical power burden of the first lens 103. By setting the first surface 1021 of the first prism 102 as a curved surface and keeping the second surface 1022 and the third surface 1023 as flat surfaces, the near-eye display optical system 100 of this application embodiment can achieve a wider field of view (up to 55° to 70°) and a thinner near-eye display optical system 100 (11mm to 13mm) without significantly increasing manufacturing costs, providing users with a near-eye display experience that combines immersion and wearing comfort.

[0063] In some optional embodiments disclosed in this application, the first prism 102 may include a plano-convex lens 1024 and a triangular prism 1025. The plano-convex lens 1024 may be formed on one surface of the triangular prism 1025. The convex surface of the plano-convex lens 1024 may constitute the first surface 1021 of the first prism 102. The other two surfaces of the triangular prism 1025 may respectively constitute the second surface 1022 and the third surface 1023 of the first prism 102. Depending on whether the plano-convex lens 1024 and the triangular prism 1025 are independently molded elements, this application provides two parallel implementations: an integral molding scheme and an independent element assembly scheme.

[0064] In some embodiments, such as Figure 1 The plano-convex lens 1024 and the prism 1025 are not two independent components, but rather different functional parts of the first prism 102. That is, the first prism 102 itself is a single optical element manufactured using a one-piece molding process. For example, a first prism 102 with a curved first surface 1021 and planar second and third surfaces 1023 can be directly manufactured using injection molding or compression molding techniques. One-piece molding refers to directly manufacturing a structure that might otherwise be composed of multiple parts into a single component through a single molding process such as injection molding, compression molding, or casting. In the field of optics, it is often used to manufacture single-piece lenses or prisms with complex surface shapes.

[0065] In other embodiments, the plano-convex lens 1024 and the prism 1025 are two independently formed optical elements, which are subsequently assembled and fixed to form a first prism 102. The plano-convex lens 1024 may have an upper surface and a lower surface, wherein the upper surface is convex and the lower surface is planar. The prism 1025 may have an upper left surface, a lower left surface, and a right surface. The lower surface of the plano-convex lens 1024 is attached to the upper left surface of the prism 1025 and is bonded together by a fixing connection, such as optical adhesive. Optionally, the lower surface of the plano-convex lens 1024 and the upper left surface of the prism 1025 may be bonded together. The plano-convex lens 1024 and the prism 1025 can be combined to form the first prism 102. The upper surface of the plano-convex lens 1024 may serve as the first surface 1021 of the first prism 102. The lower left surface of the prism 1025 may serve as the second surface 1022 of the first prism 102. The right surface of the triangular prism 1025 can serve as the third surface 1023 of the first prism 102.

[0066] In this way, assembling the separately formed plano-convex lens 1024 and prism 1025 simplifies the forming process of the first prism 102. Furthermore, since the convex surface of the plano-convex lens 1024 serves as the first surface 1021 of the first prism 102, the first surface 1021 of the first prism 102 can be aspherical, which is easier to manufacture. Aspherical surfaces can correct field curvature and pupil shift distortion, ensuring the imaging quality of the near-eye display optical system 100 and thus improving the user experience.

[0067] In some alternative embodiments disclosed in this application, such as Figure 1 , Figure 2 As shown, the near-eye display optical system 100 may further include a second prism 105. The second prism 105 may have a sixth surface 1051 and a seventh surface 1052. The sixth surface 1051 of the second prism 105 may be positioned close to the eyepiece of the near-eye display optical system 100. The seventh surface 1052 of the second prism 105 may be positioned close to the second surface 1022 of the first prism 102. Light reflected by the reflective film 104 exits the first prism 102 through the second surface 1022, passes through the seventh surface 1052 and the sixth surface 1051 of the second prism 105, and then exits into the eyepiece of the near-eye display optical system 100. When the light emitted from the image source 101 passes through the first prism 102, the light rays from different positions on the light-emitting surface of the image source 101 will pass through different parts of the first prism 102, resulting in differences in optical path. The second prism 105 is used to compensate for the optical path difference generated after the light rays propagate through different areas of the first prism 102, so as to reduce distortion.

[0068] like Figure 1 , Figure 2As shown, the second prism 105 can be a triangular prism. Both the sixth surface 1051 and the seventh surface 1052 of the second prism 105 can be planes. The sixth surface 1051 and the seventh surface 1052 of the second prism 105 can intersect. The seventh surface 1052 of the second prism 105 can be bonded to the second surface 1022 of the first prism 102, for example, by optical adhesive or direct contact.

[0069] After the light emitted from the image source 101 is reflected by the reflective film 104, the reflected light can pass through the first prism 102 to reach the seventh surface 1052 of the second prism 105 and enter the second prism 105. Then, the light can exit from the sixth surface 1051 of the second prism 105 and be emitted into the eye box.

[0070] Thus, with the introduction of the second prism 105, the light emitted from the image source 101 can enter the eye chamber of the near-eye display optical system 100. In this way, the human eye can see the display image provided by the image source 101. Furthermore, the second prism 105 can compensate for the optical path difference caused by light rays emitted from different light-emitting positions on the image source 101 propagating within the first prism 102, ensuring that the optical path lengths of light rays emitted from different light-emitting positions are essentially the same, thereby reducing image distortion and improving the imaging quality of the near-eye display optical system 100.

[0071] In some alternative embodiments disclosed in this application, such as Figure 1 , Figure 2 As shown, the near-eye display optical system 100 also includes a polarizing reflective film 106 and a quarter-wave plate 107. The polarizing reflective film 106 is disposed between the second surface 1022 of the first prism 102 and the seventh surface 1052 of the second prism 105, and the quarter-wave plate 107 is disposed between the first lens 103 and the third surface 1023 of the first prism 102.

[0072] When light emitted from image source 101 is totally internally reflected by the third surface 1023 of the first prism 102 and propagates to the polarizing reflective film 106, the polarizing reflective film 106 partially reflects the light, and the reflected light is polarized. This polarized light exits from the third surface 1023 of the first prism 102, passes sequentially through the quarter-wave plate 107 and the first lens 103, reaches the reflective film 104, and is reflected. Subsequently, the polarized light passes back through the first lens 103 and the quarter-wave plate 107. Because the light passes through the quarter-wave plate 107 twice, its polarization direction changes in a predetermined way, for example, by 90 degrees. When the light with the changed polarization direction reaches the polarizing reflective film 106 again, it can directly pass through the polarizing reflective film 106 and then enter the human eye through the second prism 105. Through the above-described polarization light path control, the system can effectively distinguish between the incident and outgoing light paths, reduce stray light, and improve light energy utilization and imaging contrast.

[0073] like Figure 1 , Figure 2 As shown, optionally, the polarizing reflective film 106 can be bonded and fixed to at least one of the second surface 1022 of the first prism 102 and the seventh surface 1052 of the second prism 105. In some embodiments, the fourth surface 1031 of the first lens 103 is spaced apart from the third surface 1023 of the first prism 102, and the quarter-wave plate 107 can be disposed on the fourth surface 1031 of the first lens 103. In this way, the stable adhesion of the polarizing reflective film 106 is ensured, and the position of the quarter-wave plate 107 is matched by the air gap, which is beneficial to the accurate control of the polarization light path.

[0074] In some cases, such as Figure 1 , Figure 2 As shown, the near-eye display optical system 100 also includes a first linear polarizer 108, which is disposed on the light-emitting side of the image source 101.

[0075] With the above configuration, the light emitted from image source 101 first passes through the first linear polarizer 108, converting it into linearly polarized light of the first type (e.g., P-polarized or S-polarized light). This linearly polarized light of the first type propagates inside the first prism 102 and is reflected when it reaches the polarizing reflective film 106. Subsequently, the light is transmitted out from the third surface 1023 of the first prism 102, and after passing through the quarter-wave plate 107, the linearly polarized light of the first type is converted into circularly polarized light of the first type. This circularly polarized light passes through the first lens 103 and propagates to the reflective film 104. After being reflected by the reflective film 104, the circularly polarized light of the first type is converted into circularly polarized light of the second type (with the opposite polarization direction). When the circularly polarized light of the second type passes through the quarter-wave plate 107 again, it is converted into linearly polarized light of the second type (with a polarization direction perpendicular to the first type). This linearly polarized light of the second type enters the first prism 102 and is incident on the polarizing reflective film 106, where it can be directly transmitted through the polarizing reflective film 106. Through the coordinated operation of the first linear polarizer 108, the polarizing reflective film 106, and the quarter-wave plate 107, the energy loss of the light source 101 during propagation is effectively reduced, and the light energy utilization rate is significantly improved.

[0076] In some optional embodiments disclosed in this application, the near-eye display optical system 100 further includes a second linear polarizer 109, which is disposed on the sixth surface 1051 of the second prism 105. The function of the second linear polarizer 109 is to further polarize and filter the outgoing light before it exits the second prism 105 and reaches the eye box, eliminating any stray light or light with undesired polarization, thereby improving image contrast, reducing interference from ambient light on the displayed image, and enhancing the user's visual experience in augmented reality viewing environments.

[0077] In some alternative embodiments disclosed in this application, such as Figure 3 As shown, Figure 3 This is a third structural schematic diagram of the near-eye display optical system provided in this application embodiment. The near-eye display optical system 100 may further include a second lens 110. The second lens 110 may be located on the side of the first lens 103 away from the first prism 102. In some cases, the second lens 110 may be attached to the reflective film 104, for example, by bonding or coating the reflective film 104 onto the second lens 110; of course, the two may also be spaced apart to maintain a certain distance.

[0078] In an optional example, the second lens 110 has an eighth surface 1101 and a ninth surface 1102 disposed opposite to each other along its own thickness direction, wherein the eighth surface 1101 compensates for the fifth surface 1032 of the first lens 103, and the ninth surface 1102 is disposed parallel to the fourth surface 1031 of the first lens 103.

[0079] In other words, the second lens 110 acts as a compensating mirror for the first lens 103, used to correct the surface profile of the first lens 103. In an optional example, the curvature of the eighth surface 1101 is complementary to that of the fifth surface 1032 of the first lens 103, meaning their radii of curvature are equal in size but opposite in sign, resulting in a combined optical power of zero. The ninth surface 1102 is arranged parallel to the fourth surface 1031 of the first lens 103. Through this complementary curvature design, the second lens 110 can compensate for the optical power loss caused by the first lens 103, allowing ambient light to pass through the near-eye display optical system 100 without deflection, achieving a clear perspective effect.

[0080] like Figure 3 As shown, light from the external environment, such as light ray e1, passes sequentially through the second lens 110, the reflective film 104, the first lens 103, the first prism 102, and the second prism 105 before finally entering the eye chamber of the near-eye display optical system 100. Through this structure, ambient light can enter the human eye without deflection, allowing the user to see an undistorted environmental image and achieve a clear perspective effect when observing the real environment while wearing a near-eye display device.

[0081] In some optional embodiments disclosed in this application, the near-eye display optical system 100 further includes a third lens 111, which is disposed between the image source 101 and the first prism 102. Light rays emitted from the image source 101 pass through the third lens 111 and enter the first surface 1021 of the first prism 102. The third lens 111 has a tenth surface 1111 and an eleventh surface 1112 along its thickness direction. The tenth surface 1111 is disposed closer to the image source 101, and the eleventh surface 1112 is disposed closer to the first surface 1021 of the first prism 102. The tenth surface 1111 is planar, and the eleventh surface 1112 is curved. The first surface 1021 is curved and has a second radius of curvature R2; the eleventh surface 1112 has a third radius of curvature R3. The ratio of the second radius of curvature R2 to the third radius of curvature R3, R2 / R3 < 0, meaning their curvature signs are opposite, which is beneficial for correcting aberrations in the near-eye display optical system 100.

[0082] In some optional embodiments disclosed in this application, the center thickness of the third lens 111 ranges from 1.5 mm to 2.5 mm. For example, the center thickness of the third lens 111 can be 1.5 mm, 1.8 mm, 2 mm, 2.3 mm, 2.5 mm, etc., which will not be listed here. By controlling the thickness of the third lens 111 within the above range, it is helpful to achieve a thinner and lighter near-eye display optical system 100 while ensuring optical power and imaging quality.

[0083] In some optional embodiments disclosed in this application, the center thickness of the first lens 103 ranges from 2.5 mm to 4.5 mm. For example, the center thickness of the first lens 103 can be 2.5 mm, 2.8 mm, 3 mm, 3.3 mm, 3.5 mm, 3.8 mm, 4 mm, 4.2 mm, 4.5 mm, etc., which will not be listed here. By controlling the thickness of the first lens 103 within the above range, it is helpful to achieve a thinner and lighter near-eye display optical system 100 while ensuring optical power and imaging quality.

[0084] In some optional embodiments disclosed in this application, the field of view (FOV) of the near-eye display optical system 100 is 55 to 70 degrees. For example, the field of view of the near-eye display optical system 100 can be 55 degrees, 58 degrees, 60 degrees, 63 degrees, 65 degrees, 68 degrees, 70 degrees, etc., and will not be listed here. In this way, users can view a clear picture within a larger field of view and obtain a better immersive experience.

[0085] In some optional embodiments disclosed in this application, the thickness of the near-eye display optical system 100 is 11 mm to 13 mm. For example, the thickness of the near-eye display optical system 100 is 11 mm, 11.2 mm, 11.6 mm, 12 mm, 12.5 mm, 12.8 mm, 13 mm, etc., and will not be listed here. It can be seen that the near-eye display optical system 100 provided in the embodiments of this application is small in size and compact in structure, which is conducive to achieving miniaturization and lightweight design, and meets the wearing comfort requirements of near-eye display devices.

[0086] This application further illustrates the near-eye display optical system 100 through several specific design examples. The following three embodiments correspond to different parameter configurations, and their optical performance is verified by modulation transfer function (MTF) curves and field curvature and astigmatism curves.

[0087] The MTF curve is a curve describing the performance of the near-eye display optical system 100 and can be used to evaluate the contrast reproduction capability of the near-eye display optical system 100. The horizontal axis represents spatial frequency (unit: period / mm), and the vertical axis represents contrast transfer ratio (0–1). The field curvature and astigmatism curves are also curves describing the performance of the near-eye display optical system 100; solid lines represent the meridional direction, and dashed lines represent the sagittal direction.

[0088] Example 1 Please see Figure 4 as well as Figure 5 , Figure 4 This is a first schematic diagram of the modulation transfer function (MTF) curve of the near-eye display optical system 100 provided in the embodiments of this application. Figure 5 This is a first schematic diagram of the field curvature and astigmatism curves of a near-eye display optical system provided in an embodiment of this application.

[0089] Combination Figure 3 , Figure 4 as well as Figure 5 The corresponding near-eye display optical system 100 can meet the following conditions: (1) the system focal length f of the near-eye display optical system 100 is 14.9485 mm; (2) the field of view (FOV) of the near-eye display optical system 100 is 59 degrees; (3) the center thickness of the third lens 111 is 1.95 mm; (4) the center thickness of the first lens 103 is 3.10645 mm; (5) the radius of curvature R1 of the fifth surface 1032 of the first lens 103 is -48.15029 mm, and the absolute value of the ratio f / R1 of the system focal length f to the first radius of curvature R1 is 0.31. It is worth noting that the fifth surface 1032 of the first lens 103 reflects image light under the action of the reflective film 104, making the sign of the radius of curvature negative.

[0090] Table 1 is arranged in reverse optical path according to optical design conventions, that is, starting from the virtual image plane on the eye box side and tracing back to the image plane on the image source side. The correspondence between the surface numbers and the physical elements in the near-eye display optical system 100 is as follows.

[0091] Surface S1 is the virtual image plane, corresponding to the virtual image plane seen by the human eye from the eye box side, approximately 2500mm from the eye box. Surface S2 is the exit pupil position of the system. Surface S3 is the sixth surface 1051 of the second prism 105, on which a second linear polarizer 109 can be installed. Surface S4 is the seventh surface 1052 of the second prism 105, adjacent to the polarizing reflective film 106. Surface S5 is the fourth surface 1031 of the first lens 103, a plane, on which a quarter-wave plate 107 can be installed. Surface S6 is the fifth surface 1032 of the first lens 103, a reflective curved surface, on which a reflective film 104 is installed. Surface S7 is the fourth surface 1031 of the first lens 103. Surface S8 is the third surface 1023 of the first prism 102, on which light passes twice: first exiting from inside the first prism 102, and then re-entering the first prism 102 from the outside. Surface S9 is the second surface 1022 of the first prism 102, a reflecting plane, where the polarizing reflective film 106 is disposed to reflect light rays with a specific polarization direction. Surface S10 is the third surface 1023 of the first prism 102, where total internal reflection occurs, and is the same physical surface as surface S8. Surface S11 is the first surface 1021 of the first prism 102, an aspherical surface, and is the incident surface where light rays enter the first prism 102. Surface S12 is the eleventh surface 1112 of the third lens 111, an aspherical surface. Surface S13 is the tenth surface 1111 of the third lens 111, a plane. Surface S14 is the first linear polarizer 108, located on the light-emitting side of the image source 101. Surface S15 is the image plane, corresponding to the light-emitting surface of the image source 101.

[0092] The light transmission path of this embodiment will be described in detail below, referring to the surface numbers in Table 1 and following the reverse optical path sequence adopted in the optical design. The reverse optical path tracing starts from the human eye side and gradually traces back to the image source.

[0093] The retrograde light emitted from the virtual image surface (surface S1) passes through the system exit pupil (surface S2), and then sequentially through the second linear polarizer 109 and the sixth surface 1051 (surface S3) of the second prism 105, propagating inside the second prism 105. Subsequently, the retrograde light exits from the seventh surface 1052 (surface S4) of the second prism 105 and reaches the polarizing reflective film 106. Since the retrograde light corresponds to the outgoing light whose polarization direction has been rotated by 90° in the forward light path, and the polarization direction of this retrograde light matches the transmission axis of the polarizing reflective film 106, it directly transmits through the polarizing reflective film 106 and then enters the first prism 102.

[0094] After the retrograde light enters the first prism 102, it propagates to the third surface 1023 (surface S8) of the first prism 102, exits from this surface, passes through the fourth surface 1031 (surface S7) of the first lens 103, and then passes through the quarter-wave plate 107. The quarter-wave plate 107 converts the polarization state of the retrograde light from linearly polarized light to circularly polarized light. Subsequently, the circularly polarized retrograde light enters the first lens 103 from the fourth surface 1031 (surface S5) and propagates within it to the fifth surface 1032 (surface S6). At the fifth surface 1032, the reflective film 104 reflects the retrograde light, and the reflected retrograde light is reversed in direction. Afterward, the reversed retrograde light passes through the first lens 103 again, exits from the fourth surface 1031 (surface S5), and passes through the quarter-wave plate 107 again. After the reverse light passes through the quarter-wave plate 107 twice, its polarization direction is rotated by 90° relative to the initial incident direction, and it is converted from circularly polarized light back to linearly polarized light, with a different polarization direction than when it entered.

[0095] The reverse light, after its polarization direction has changed, passes through the fourth surface 1031 (surface S7) of the first lens 103 and re-enters the first prism 102 through the third surface 1023 (surface S8). The reverse light propagates inside the first prism 102 to the second surface 1022 (surface S9). Since the polarization direction of the reverse light matches the reflection axis of the polarizing reflective film 106 at this point, the polarizing reflective film 106 reflects the reverse light. The reflected reverse light continues to propagate within the first prism 102 and reaches the third surface 1023 (surface S10), where total internal reflection occurs. After total internal reflection, the reverse light continues to propagate within the first prism 102 and finally exits the first prism 102 through the first surface 1021 (surface S11).

[0096] The retrograde light rays exiting the first prism 102 enter the third lens 111 through the eleventh surface 1112 (surface S12), propagate within the third lens 111, and exit through the tenth surface 1111 (surface S13). Subsequently, the retrograde light rays pass through the first linear polarizer 108 (surface S14) and finally reach the image plane (surface S15) of the image source 101.

[0097] The light transmission path of this embodiment will be described below with reference to the surface numbers in Table 1, according to the forward light path sequence in actual use. The forward light path starts from the image source 101 and reaches the eye box where the human eye is located.

[0098] Light emitted from the image plane (surface S15) of image source 101 first passes through the first linear polarizer 108 (surface S14) and is converted into linearly polarized light of the first type. Subsequently, this linearly polarized light enters the third lens 111 through the tenth surface 1111 (surface S13), propagates within the third lens 111, and exits through the eleventh surface 1112 (surface S12). The exited linearly polarized light then enters the first prism 102 through the first surface 1021 (surface S11).

[0099] After linearly polarized light enters the first prism 102, it propagates inside to the third surface 1023, i.e., surface S10, where total internal reflection occurs. The reflected light then refracts to the second surface 1022, i.e., surface S9. At the second surface 1022, the polarizing reflective film 106 reflects the linearly polarized light, which then propagates again to the third surface 1023, i.e., surface S8, from which it exits the first prism 102.

[0100] The linearly polarized light exiting the first prism 102 passes through the fourth surface 1031 (surface S7) of the first lens 103 and then through the quarter-wave plate 107, where it is converted into circularly polarized light of the first type. This circularly polarized light then enters the first lens 103 again through the fourth surface 1031 (surface S5) and propagates to the fifth surface 1032 (surface S6). At the fifth surface 1032, the reflective film 104 reflects the light, reversing the rotation direction of the circularly polarized light. The rotated light then passes through the first lens 103 again, exits through the fourth surface 1031 (surface S5), and passes through the quarter-wave plate 107 again. Because the light passes through the quarter-wave plate 107 twice, its polarization direction is rotated by 90° relative to its initial polarization, converting it from circularly polarized light into linearly polarized light of the second type.

[0101] The second type of linearly polarized light, after passing through the fourth surface 1031 (surface S7) of the first lens 103, re-enters the first prism 102 through the third surface 1023 (surface S8). This linearly polarized light propagates within the first prism 102 to the polarizing reflective film 106. Since the polarization direction of the second type of linearly polarized light matches the transmission axis of the polarizing reflective film 106, the light directly passes through the polarizing reflective film 106 and enters the second prism 105 through the seventh surface 1052 (surface S4). Subsequently, the light passes through the second prism 105, exits through the sixth surface 1051 (surface S3), passes through the second linear polarizer 109, and exits through the system exit pupil (surface S2) to the eyepiece. The human eye perceives a clear virtual image at the virtual image plane (surface S1).

[0102] Table 1

[0103] Table 2

[0104] In terms of parameter characteristics, the system focal length f of this embodiment is 14.9485mm, the first radius of curvature R1 of the fifth surface 1032 of the first lens 103 is -48.15029mm, and the absolute value of f / R1 is 0.31.

[0105] It is worth noting that the fifth surface 1032 of the first lens 103 reflects image light under the action of the reflective film 104, making the sign of the first radius of curvature negative.

[0106] The value of |f / R1| is 0.31, which is relatively low in this range, indicating that the fifth surface 1032 of the first lens 103 has a moderate degree of curvature relative to the system focal length. This degree of curvature provides sufficient optical power for the optical system without excessively introducing spherical aberration and astigmatism, while keeping the total system thickness at approximately 12 mm. The center thickness of the third lens 111 is 1.95 mm, which contributes to the system's thinness while ensuring optical power. The center thickness of the first lens 103 is 3.10645 mm, providing sufficient thickness to support the curved surface while avoiding an increase in system volume due to excessive thickness. The field of view in this embodiment is 59 degrees.

[0107] from Figure 4 The MTF curves shown indicate that the spatial frequency range of the horizontal axis is 0 to 18 cycles / mm. Within this frequency range, the modulation transfer function (MTF) values ​​for each field of view are close to 1.0, even at the highest spatial frequency of 18 cycles / mm, the MTF value remains around 1.0. Furthermore, the curves along the meridional direction (solid line) and the sagittal direction (dashed line) almost completely overlap across the entire field of view. These results demonstrate that the optical system exhibits near-lossless contrast transfer capability in the low- to mid-frequency range, and astigmatism is corrected, resulting in excellent imaging consistency.

[0108] from Figure 5 As can be seen from the field curvature and astigmatism curves, both the meridional field curvature and the sagittal field curvature are controlled within a small range. The maximum difference between the two, i.e., the astigmatism, is small, indicating that the image plane is flat and users can obtain clear images at different viewing positions.

[0109] Example 2 Please see Figure 6 as well as Figure 7 , Figure 6 This is a second schematic diagram of the modulation transfer function curve of the near-eye display optical system provided in the embodiments of this application. Figure 7 This is a second schematic diagram of the field curvature and astigmatism curves of a near-eye display optical system provided in an embodiment of this application.

[0110] Combination Figure 2 , Figure 6 as well as Figure 7 The corresponding near-eye display optical system 100 can meet the following conditions: (1) The system focal length f of the near-eye display optical system 100 is 17.01 mm; (2) The field of view (FOV) of the near-eye display optical system 100 is 70 degrees; (3) The center thickness of the first lens 103 is 3 mm; (4) The absolute value of the ratio f / R1 of the system focal length f to the first radius of curvature R1 is 0.36.

[0111] Table 3 is arranged along the reverse optical path according to optical design conventions. The difference from Embodiment 1 is that this embodiment does not include a third lens 111; instead, a linear polarizer and cover glass are placed between the image source 101 and the first surface 1021 of the first prism 102. The correspondence between the surface numbers and the physical elements in the near-eye display optical system 100 is as follows.

[0112] Surface S1 is the virtual image plane, corresponding to the virtual image plane seen by the human eye from the eye box side, approximately 2500mm from the eye box. Surface S2 is the exit pupil position of the system. Surface S3 is the sixth surface 1051 of the second prism 105, on which a second linear polarizer 109 can be installed. Surface S4 is the seventh surface 1052 of the second prism 105, adjacent to the polarizing reflective film 106. Surface S5 is the fourth surface 1031 of the first lens 103, a plane, on which a quarter-wave plate 107 can be installed. Surface S6 is the fifth surface 1032 of the first lens 103, a reflective curved surface, on which a reflective film 104 is installed. Surface S7 is the fourth surface 1031 of the first lens 103. Surface S8 is the third surface 1023 of the first prism 102, on which light passes twice: first exiting from inside the first prism 102, and then re-entering the first prism 102 from the outside. Surface S9 is the second surface 1022 of the first prism 102, a reflecting plane, where the polarizing reflective film 106 is disposed to reflect light rays with a specific polarization direction. Surface S10 is the third surface 1023 of the first prism 102, where total internal reflection occurs, and is the same physical surface as surface S8. Surface S11 is the first surface 1021 of the first prism 102, an aspherical surface, and is the incident surface where light rays enter the first prism 102. Surface S12 is the image plane, corresponding to the emitting surface of the image source 101.

[0113] Compared with Embodiment 1, the reverse optical path of this embodiment directly reaches the image plane, i.e., surface S12, after exiting the first surface 1021, i.e., surface S11, of the first prism 102, without passing through the third lens 111. Therefore, the optical path of Embodiment 2 of this application is simpler, and the distance between the image source 101 and the first prism 102 is smaller.

[0114] Table 3

[0115] Table 4

[0116] In terms of parameter characteristics, the system focal length f of this embodiment is 17.01 mm, the first radius of curvature R1 of the fifth surface 1032 of the first lens 103 is -47.33409 mm, and the absolute value of f / R1 is 0.36.

[0117] It is worth noting that the fifth surface 1032 of the first lens 103 reflects image light under the action of the reflective film 104, making the sign of the first radius of curvature negative.

[0118] The value of |f / R1| is 0.36, which is in the upper-middle range. Compared to 0.31 in Embodiment 1, the fifth surface 1032 of the first lens 103 in this embodiment is more curved relative to the system focal length, providing stronger optical power for a large field of view of 70 degrees. The center thickness of the first lens 103 is 3mm, which takes into account the requirements of thinness and lightness while ensuring surface accuracy and optical power. The field of view of this embodiment is 70 degrees. In particular, this embodiment satisfies the preferred conditions mentioned above, that is, the absolute value of f / R1 satisfies: 0.34≤|f / R1|≤0.4, and the field of view of the optical system is 65 degrees to 70 degrees, that is, the value range of f / R1 is further optimized under the condition of a large field of view.

[0119] from Figure 6 The MTF curves shown indicate that the spatial frequency range of the horizontal axis is from 0 to 16.34 cycles / mm. Within this frequency range, the modulation transfer function (MTF) value of the central field of view remains consistently around 1.0; the MTF value of the peripheral field of view is close to 1.0 in the low-frequency range, decreases slightly with increasing spatial frequency, and remains above 0.80 at the highest spatial frequency of 16.34 cycles / mm. Furthermore, the curves in the meridional direction (solid line) and the sagittal direction (dashed line) show little difference across the entire field of view, indicating that the optical system maintains good resolution and imaging consistency even at a large field of view of 70°, meeting the clarity requirements of near-eye display devices.

[0120] from Figure 7 As shown in the field curvature and astigmatism curves, both the meridional field curvature and the sagittal field curvature are within a small range, and the astigmatism is controlled within an acceptable range, which meets the requirements for a flat image field under a large field of view and is conducive to improving viewing comfort.

[0121] In the parameter values ​​of the above embodiments, such as the absolute value of f / R1 satisfying: 0.3≤|f / R1|≤0.4, the field of view being 55 degrees to 70 degrees, and the thickness of the near-eye display optical system 100 being 11mm to 13mm, it has been verified that the near-eye display optical system 100 can achieve thinness, a large field of view, and high imaging quality under different configurations. Actual products can select any embodiment or make minor parameter adjustments based on it according to specific design specifications, without departing from the protection scope of this application.

[0122] In summary, the near-eye display optical system 100 provided by the embodiments disclosed in this application can achieve a larger eye box and a larger field of view in a smaller volume, thereby ensuring image quality.

[0123] This application also provides a near-eye display device. The near-eye display device may include a frame structure and the near-eye display optical system 100 from any of the above embodiments. The near-eye display optical system 100 may be mounted on the frame structure.

[0124] In some alternative embodiments disclosed in this application, the frame structure can be a structure capable of supporting and accommodating the near-eye display optical system 100. For example, the frame structure may include eyeglass frames, headbands, etc.

[0125] The frame structure allows for reliable fixation and wearing of the near-eye display optical system 100. Through the coordinated operation of the components within the near-eye display optical system 100, the display image provided by the image source 101 can be projected onto the eye box, meeting the user's viewing needs. In some embodiments, the user can also simultaneously observe the external environment through this device, achieving an augmented reality effect.

[0126] It should be noted that the various optional embodiments and implementation methods disclosed above can be flexibly selected and combined as needed to achieve the corresponding functions and effects. This application does not list them all.

[0127] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0128] The near-eye display optical system and near-eye display device provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application, and the descriptions of the embodiments above are only for the purpose of helping to understand this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A near-eye display optical system, characterized in that, include: Image source; A first prism has a first surface, a second surface, and a third surface. The first surface of the first prism is disposed close to the image source, and the second surface of the first prism is disposed close to the eye box of the near-eye display optical system. A first lens has a fourth surface and a fifth surface disposed opposite to each other along its own thickness direction. The fourth surface is disposed close to the third surface, and the fifth surface is a curved surface with a first radius of curvature R1. A reflective film is disposed on one side near the fifth surface of the first lens; The light emitted from the image source is incident on the first surface of the first prism. After at least one total internal reflection occurs in the first prism, the light exits from the third surface of the first prism to the first lens. The light reflected by the reflective film enters the first prism again from the third surface and then exits from the second surface to the eye box of the near-eye display optical system. The near-eye display optical system satisfies the following: the absolute value of the ratio f / R1 of the system focal length f of the near-eye display optical system to the first radius of curvature R1 satisfies: 0.3≤|f / R1|≤0.

4.

2. The near-eye display optical system according to claim 1, characterized in that, The absolute value of the ratio f / R1 of the system focal length f of the near-eye display optical system to the first radius of curvature R1 satisfies: 0.31≤|f / R1|≤0.

36.

3. The near-eye display optical system according to claim 1, characterized in that, The light emitted from the image source is incident on the first surface of the first prism, and after being reflected by the third surface of the first prism and the second surface of the first prism, it propagates again to the third surface of the first prism and exits from the third surface of the first prism.

4. The near-eye display optical system according to claim 1, characterized in that, The first surface has a second radius of curvature R2, where the second radius of curvature R2 ≥ 0.

5. The near-eye display optical system according to any one of claims 1 to 4, characterized in that, The near-eye display optical system further includes a second prism, which has a sixth surface and a seventh surface. The sixth surface of the second prism is disposed close to the eye box of the near-eye display optical system, and the seventh surface of the second prism is disposed close to the second surface of the first prism. After being reflected by the reflective film, the light emitted from the second surface exits the first prism, passes through the seventh surface and the sixth surface of the second prism, and then exits the eye box of the near-eye display optical system.

6. The near-eye display optical system according to claim 5, characterized in that, It also includes a polarizing reflective film and a quarter-wave plate, wherein the polarizing reflective film is disposed between the second surface of the first prism and the seventh surface of the second prism, and the quarter-wave plate is disposed between the first lens and the third surface of the first prism.

7. The near-eye display optical system according to claim 6, characterized in that, The fourth surface of the first lens is spaced apart from the third surface of the first prism, and the quarter-wave plate is disposed on the fourth surface of the first lens.

8. The near-eye display optical system according to claim 6, characterized in that, It also includes a first linear polarizer, which is disposed on the light-emitting side of the image source.

9. The near-eye display optical system according to claim 5, characterized in that, It also includes a second linear polarizer, which is disposed on the sixth surface of the second prism.

10. The near-eye display optical system according to any one of claims 1 to 4, characterized in that, The near-eye display optical system further includes a second lens located on the side of the first lens away from the first prism.

11. The near-eye display optical system according to claim 10, characterized in that, The second lens has an eighth surface and a ninth surface that are arranged opposite to each other along its own thickness direction. The eighth surface and the fifth surface compensate for each other, and the ninth surface is arranged parallel to the fourth surface.

12. The near-eye display optical system according to any one of claims 1 to 4, characterized in that, The near-eye display optical system further includes a third lens, which is disposed between the image source and the first prism. The light emitted from the image source passes through the third lens and then enters the first surface of the first prism.

13. The near-eye display optical system according to claim 12, characterized in that, The third lens has a tenth surface and an eleventh surface along its own thickness direction. The tenth surface is located close to the image source, and the eleventh surface is located close to the first surface of the first prism. The tenth surface is a plane, and the eleventh surface is a curved surface.

14. The near-eye display optical system according to claim 13, characterized in that, The first surface is a curved surface and has a second radius of curvature R2; the eleventh surface has a third radius of curvature R3, and the ratio of the second radius of curvature R2 to the third radius of curvature R3 is R2 / R3 < 0.

15. The near-eye display optical system according to claim 12, characterized in that, The center thickness of the third lens ranges from 1.5 mm to 2.5 mm.

16. The near-eye display optical system according to any one of claims 1 to 4, characterized in that, The center thickness of the first lens ranges from 2.5 mm to 4.5 mm.

17. The near-eye display optical system according to any one of claims 1 to 4, characterized in that, The field of view of the near-eye display optical system is 55 to 70 degrees.

18. The near-eye display optical system according to any one of claims 1 to 4, characterized in that, The absolute value of f / R1 satisfies: 0.34≤|f / R1|≤0.4; the field of view of the near-eye display optical system is 65 degrees to 70 degrees.

19. The near-eye display optical system according to any one of claims 1 to 4, characterized in that, The thickness of the near-eye display optical system is 11 mm to 13 mm.

20. A near-eye display device, characterized in that, include: Framework structure; The near-eye display optical system as described in any one of claims 1 to 19, wherein the near-eye display optical system is mounted on the frame structure.

Images