A bifocal near-eye display optical system

Abstract

The application discloses a kind of bifocal near-eye display optical systems, including first display light path and second display light path;First display light path, including prism group and first lens group, prism group includes main prism, auxiliary prism and compensation prism;Second display light path, including prism group and second lens group;Wherein, first display light path and second display light path share prism group, for first display light path, only main prism and auxiliary prism of prism group are used for imaging, for second display light path, ambient light is imaged by passing through prism group;First display light path has first display focal plane;Second display light path has second display focal plane, and the position of first display focal plane and second display focal plane is different.The above-mentioned bifocal near-eye display optical system, by prism group, two display light paths are combined, and two display light paths respectively form display focal plane of different positions;Person's eye can be switched between two focal planes, so that person's eye is exercised, and vision prevention and control are carried out.

Description

Technical Field

[0001] The present invention relates to an optical system, and in particular to a near-eye display optical system with dual focal planes. Background Art

[0002] Children and adolescents are in the growth and development period and the peak period of eye use. Helping them to develop good eye habits, conduct scientific physical exercises and training for the eyes and visual system, enhance the eye's ability to adjust, help prevent and control myopia, repair amblyopia, improve the health of naked eye vision, and reduce dependence on glasses, surgery and other vision correction methods.

[0003] The dual-focal plane augmented reality near-eye display optical system can exercise the eye function by regularly changing the depth of focus, fully mobilize the potential of the eyes, relieve visual fatigue, improve the adjustment speed, increase the adjustment range, and effectively improve the adjustment lag and insufficient adjustment function. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a dual-focal-plane near-eye display optical system.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] A dual-focal-plane near-eye display optical system comprising:

[0007] A first display optical path includes a prism group and a first lens group; the prism group includes a main prism, an auxiliary prism, and a compensation prism; the main prism includes a first optical surface, a second optical surface, and a third optical surface; the first optical surface is an incident surface; the second optical surface is disposed close to the human eye; the third optical surface is disposed away from the human eye and is provided with a dichroic film; the auxiliary prism is disposed on the side of the second optical surface; and the compensation prism is disposed on the side of the third optical surface; the first light refracted by the first lens group passes through the first optical surface and enters the main prism, is totally reflected by the second optical surface, is partially reflected by the third optical surface, passes through the second optical surface, and then passes through the auxiliary prism to reach the human eye; the first display optical path has a first display focal plane;

[0008] The second display optical path shares the prism group with the first display optical path; the second display optical path includes the prism group and a second lens group; the second light refracted by the second lens group passes through the compensation prism, the main prism, and the auxiliary prism in sequence to reach the human eye; the second display optical path has a second display focal plane;

[0009] The first display focal plane and the second display focal plane are at different positions.

[0010] Preferably, the prism group is equivalent to a lens with positive focal power for the second display light path; the focal length ranges from 80mm to 300mm.

[0011] Preferably, there is a gap of less than 1mm between the main prism and the auxiliary prism, and the main prism and the compensation prism are cemented.

[0012] Preferably, the first optical surface and / or the third optical surface are free-form surfaces.

[0013] Preferably, the focal length of the first display light path is 17mm

[0014] Preferably, the exit pupil distance of the first display light path and the second display light path is between 15mm and 25mm.

[0015] Preferably, the variation range of one focal surface position is not more than -200mm, and the variation range of the other focal surface position is not less than +200mm.

[0016] Preferably, the corresponding diopter of one focal surface is -5D to -0D, and the corresponding diopter of the other focal surface is +0D to +5D.

[0017] Preferably, the bifocal near-eye display optical system further comprises:

[0018] a first micro display to provide the first light rays to the first lens group; and

[0019] a second micro display to provide the second light rays to the second lens group.

[0020] Preferably, the first micro display and / or the second micro display can be moved along the central field of view central light direction to change the focal surface position.

[0021] The bifocal near-eye display optical system provided by the present application forms focal surfaces with different positions through the first display light path and the second display light path; the human eye can switch between the two focal surfaces, so that the human eye is exercised and the vision is prevented and controlled; or one of the display light paths is defocused to display, realizing defocus stimulation and preventing and controlling the vision. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic diagram of the bifocal near-eye display optical system provided by the present application;

[0023] Figure 2 is a structural schematic diagram of the first display light path of the first embodiment of the present application;

[0024] Figure 3 is a schematic diagram of an optical path of a first display light path of the first embodiment of the present application;

[0025] Figure 4 is a schematic diagram of an optical surface of the first display light path of the first embodiment of the present application;

[0026] Figure 5 is a schematic diagram of a second display light path structure of the first embodiment of the present application;

[0027] Figure 6 is a schematic diagram of an optical path of the second display light path of the first embodiment of the present application;

[0028] Figure 7 is a schematic diagram of an optical surface of the second display light path of the first embodiment of the present application;

[0029] Figure 8 is a schematic diagram of a second display light path element of the second embodiment of the present application;

[0030] Figure 9 is a schematic diagram of an optical surface of the second display light path of the second embodiment of the present application;

[0031] Figure 10 is a schematic diagram of a second display light path element of the third embodiment of the present application;

[0032] Figure 11 is a schematic diagram of an optical surface of the second display light path of the third embodiment of the present application. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0034] As shown in Figure 1 , the present application provides a bifocal near-eye display optical system, which comprises a first display light path 1 and a second display light path 2, the first display light path 1 has a first display focal plane, the second display light path 2 has a second display focal plane, the positions of the first display focal plane and the second display focal plane can be the same or different. Preferably, the positions of the first display focal plane and the second display focal plane are different, which is used for myopia prevention and control. Wherein:

[0035] As shown in Figures 2 to 4As shown, the first display optical path 1 includes a prism group 12, a first lens group 13 and a first microdisplay 14; the prism group 12 includes a main prism 122, an auxiliary prism 121 and a compensation prism 123, and the main prism 122 includes a first optical surface 1206, a second optical surface 1203 (1205) and a third optical surface 1204; the first optical surface 1206 is an incident surface, the second optical surface 1203 is arranged close to the human eye, and the third optical surface 1204 is arranged away from the human eye and is provided with a dichroic film; the auxiliary prism 121 is arranged on the second optical surface side of the main prism 122, and there is a gap of less than 1 mm between the main prism 122 and the auxiliary prism 121 to ensure the total reflection effect in the main prism 122; the compensation prism 123 is arranged on the third optical surface side of the main prism 122, and the main prism 122 and the compensation prism 123 are glued together. The light emitted by the first microdisplay 14 is refracted by the first lens group 13, enters the main prism 122 through the first optical surface 1206, is totally reflected by the second optical surface 1205, is partially reflected by the third optical surface 1204, passes through the second optical surface 1203 (the same optical surface as 1205), and then passes through the auxiliary prism 121 to reach the human eye 11 (equivalent to the aperture 111); in the first display optical path, the light that passes through the third optical surface 1204 and enters the compensation prism 123 is not used to form an image for the human eye.

[0036] like Figures 5 to 7 As shown, the second display optical path 2 includes the prism group 12, the second lens group 23 and the second microdisplay 24; the second display optical path 2 and the first display optical path 1 share the prism group 12; for the second display optical path 2, the prism group 12 is equivalent to an equivalent lens 22; the light emitted by the second microdisplay 24 is refracted by the second lens group 23, and then refracted by the compensation prism 123, the main prism 122 and the auxiliary prism 121 in the prism group 12 in sequence before reaching the human eye 21.

[0037] like Figure 1 As shown, the prism group 12 is arranged in front of the human eye, and the micro display 14 and the first lens group 13 in the first display light path 1 are arranged on the light incident side of the main prism 122, as shown in FIG. Figure 1 The image is shown above the prism assembly 12. The microdisplay 24 and second lens assembly 23 in the second display optical path 2 are coaxially arranged with the equivalent lens 22 (i.e., the prism assembly 12), positioned in the direction of the visual axis. The prism assembly 12 (i.e., the equivalent lens 22) serves as the light combining element for the first display optical path 1 and the second display optical path 2. Light from the first microdisplay 14 and the second microdisplay 24 passes through the prism assembly 12 and enters the human eye simultaneously. The first display optical path 1 and the second display optical path 2 each form a focal plane at a different location.

[0038] As shown above, the bifocal near-eye display optical system can be applied as a VR device. By forming different focal planes through the first display light path and the second display light path, the human eye can switch between the two focal planes, thereby performing vision training and preventing vision loss.

[0039] In the bifocal near-eye display optical system, the focal plane positions of the two display light paths can also be changed. The image distance is defined as positive on the side away from the human eye in the overall optical structure, and as negative on the side close to the human eye, wherein the focal plane formed by the positive image distance is the focus plane, and the image formed is the focused image, and the focal plane formed by the negative image distance is the defocus plane, and the image formed is the defocused image.

[0040] Specifically, the first micro display 14 can be moved along the central field of view central light direction to change the focal plane position of the first display light path 1; the second micro display 24 can be moved along the central field of view central light direction to change the focal plane position of the second display light path 2.

[0041] Preferably, the focal planes of the first display light path and the second display light path belong to the implementation of positive and negative diopter, wherein the range of change of the position of one focal plane is not more than-200mm, and the range of change of the position of the other focal plane is not less than +200mm, which can be adapted to myopic population and realize positive defocus display. One focal plane corresponds to a diopter of-5D to-0D, and the other focal plane corresponds to a diopter of +0D to +5D.

[0042] It can be understood that the focal plane positions of the first display light path and the second display light path can also be changed in other ranges. For example, the focal plane positions of the first display light path and the second display light path are both changed in a range of not more than-200mm to adapt to hyperopia population, or both are changed in a range of not less than +200mm to adapt to myopia population, and the above technical solutions can be realized and have corresponding application scenarios. The above range of focal plane position change is only used as an example for description and does not constitute a limitation on the technical solution.

[0043] The following is a specific example description taking the human eye as the coordinate axis origin, the human eye visual axis as the Z axis, the vertical direction perpendicular to the visual axis as the Y axis, and the horizontal direction perpendicular to the visual axis as the X axis.

[0044] First embodiment

[0045] As shown in Figures 2 to 4 , the first display light path 1 includes a prism group 12, a first lens group 13, and a first micro display 14.

[0046] The first micro display 14 provides an image source for the first display optical path 1 , and the display may be OLED, MircoLED, LCD, Lcos, etc. Preferably, an OLED micro display may be used to reduce the system volume.

[0047] In this embodiment, the first lens group 13 includes a lens 131 and a lens 132. The focal length of the lens group is 25 mm to 40 mm. Lens 131 and lens 132 can be independent positive lenses and negative lenses, or they can form a positive-negative doublet lens, wherein the positive lens 132 is arranged close to the first microdisplay 14, and the negative lens 131 is arranged close to the prism group 12. The surface shapes of lens 131 and lens 132 can be described as spherical or aspherical. The material of lens 131 and lens 132 can be glass or resin. Preferably, resin material can be used to reduce the weight of the system. The lens surfaces in the lens group 13 all have a refracting effect on light. Preferably, each optical surface in the lens group 13 needs to be coated with an anti-reflection film to increase the utilization rate of light energy and reduce possible stray light.

[0048] The prism assembly 12 comprises an auxiliary prism 121, a main prism 122, and an auxiliary prism 123 arranged along the visual axis. The main prism 122 is the primary component for optical path deflection and provides the system's primary optical power. The auxiliary prism 121 is primarily used to adjust the optical path lengths of light rays from different fields of view in the first display optical path, ensuring that the optical path lengths of light rays from each field of view are as close as possible. The compensating prism 123 is added to reduce the design complexity of the second display optical path 2 and prevents the human eye from imaging light rays entering it from the first display optical path 1.

[0049] like Figure 4 As shown, the main prism 122 includes a first optical surface 1206, a second optical surface 1203 (1205), and a third optical surface 1204. The third optical surface 1204 is provided with a dichroic film. Preferably, the dichroic film has a light splitting efficiency of 50%, that is, 50% of the light is reflected and continues to propagate toward the human eye, and the remaining 50% of the light is transmitted and lost. Depending on the brightness of the first microdisplay 14 and the second microdisplay 24, as well as the final imaging requirements of the two focal planes, dichroic films with other transmission and reflection ratios may also be used.

[0050] The auxiliary prism 121 is disposed on the second optical surface 1203 side of the main prism 122 and includes a fourth optical surface 1202 and a fifth optical surface 1201. The compensation prism 123 is disposed on the third optical surface 1204 side of the main prism 122 and includes a sixth optical surface 1208 and a seventh optical surface 1207.

[0051] Among them, the optical surface of the prism group 12 can be designed with a spherical surface, an aspherical surface, or a free-form surface. Preferably, the first optical surface 1206 and the third optical surface 1204 of the main prism 122 are designed with a free-form surface to improve the display effect of the system. The fourth optical surface 1202 of the auxiliary prism 121 has a surface shape consistent with the second optical surface 1203. There is a gap between the two to ensure total reflection of the second optical surface 1203. The seventh optical surface 1207 of the compensation prism 123 is consistent with the surface shape of the third optical surface 1204, and the compensation prism 123 and the main prism 122 are glued together. The surface shape of the fifth optical surface 1205 is determined by the first display light path, and the difference in surface shape between the sixth optical surface 1208 and the fifth optical surface 1205 forms the optical focal length of the prism group 12 to cooperate with the second lens group 23 to realize imaging of the second display light path. Preferably, in order to simplify the design difficulty of the second display light path, the prism group 12 has a positive optical focal length; the focal length range is: 80mm <f<300mm。

[0052] The prism assembly 12 can be produced by injection molding, which can reduce the weight of the prism and the cost.

[0053] In the first display optical path, light emitted from the first microdisplay 14 is refracted by lenses 132 and 131 before passing through the first optical surface 1206 and entering the primary prism 122. After the image signal enters the primary prism 122, it undergoes total internal reflection at the second optical surface 1205, is partially reflected by the third optical surface 1204, and then passes through the second optical surface 1203 (the same optical surface as 1205) before entering the auxiliary prism 121. The light then passes through the fourth optical surface 1202 and the fifth optical surface 1201 of the auxiliary prism 121 before reaching the human eye 11. In the first display optical path 1, the light entering the compensation prism 123 is not used to form an image in the human eye.

[0054] When the image signal first reaches second optical surface 1205, the light containing the image signal undergoes total internal reflection. Surface 1203 and surface 1205 are actually the same surface. However, when the light passes through this surface a second time, the light no longer meets the total internal reflection condition and passes through surface 1203 to reach surface 1202. To ensure the total internal reflection condition on surface 1205, a small air gap must be maintained between surfaces 1202 and 1205.

[0055] like Figures 5 to 7 As shown, the second display optical path 2 includes an equivalent lens 22 , a second lens group 23 and a second micro display 24 ; the second display optical path 2 and the first display optical path 1 share the prism group 12 , and the prism group 12 is equivalent to the equivalent lens 22 .

[0056] The micro display 24, which provides an image source for the second display light path 2, has the same function as the micro display 14. The display can be an OLED, a Mirco LED, an LCD, an Lcos, etc. Preferably, in order to reduce the size of the system, an OLED micro display can be used.

[0057] In this embodiment, the second lens group 23 comprises lenses 231, 232, 233, 234, and 235 arranged in sequence, wherein the lens 231 near the human eye side is a biconvex lens or a plano-convex lens convex to the human eye; the lens 232 and the lens 233 form a positive-negative double cemented lens, the lens 232 is a positive lens, the lens 233 is a negative lens, the side of the lens 232 facing the human eye is convex, and the side of the lens 233 facing the second display is concave; the lens 234 is a biconvex lens; and the lens 235 is a biconcave lens or a plano-concave lens concave to the human eye side. The focal length of the lens group 231-235 is about 25mm-40mm. The surfaces of the lenses 231-235 can be described by spherical or aspherical surfaces. Similarly, the materials of the lenses 231-235 can be glass or resin, and preferably, resin materials can be used to reduce the weight of the system.

[0058] The equivalent lens 22 is equivalent to the prism group 12 and has the same optical properties as the prism group 12. The main prism 122 and the auxiliary prism 121 are shared by the two display light paths, and the auxiliary prism 123 is only used for the second display light path imaging.

[0059] In the second display light path 2, the light emitted by the second micro display 24 passes through the lenses 235, 234, 233, 232, and 231 in sequence and is refracted to reach the equivalent lens 22. The surfaces of the lenses in the lens group 23 all have refractive effects on the light rays, and the surfaces in the lens group 23 need to be coated with an antireflection film to increase the utilization of light energy and reduce possible stray light.

[0060] The light reaching the equivalent lens 22 passes through the sixth optical surface 1208, the seventh optical surface 1207, the third optical surface 1204, the second optical surface 1203, the fourth optical surface 1202, and the fifth optical surface 1201 in sequence and is refracted to reach the human eye 21. When the image signal reaches the surface 1204, the surface 1204 is coated with a light splitting film, and the splitting efficiency is preferably 50%, i.e. 50% of the light rays continue to propagate towards the human eye after refraction, and the other 50% of the light rays are reflected and lost.

[0061] The first micro display 14 and the second micro display 24 can move along the central light ray direction of the respective central field of view, so the focal plane positions of the first display light path 1 and the second display light path 2 can be adjusted by moving the micro displays.

[0062] Table 1 to Table 5 are respectively the parameter examples of each optical surface in this embodiment. As shown in Table 1, in the first display light path, the front surface 1303 and the rear surface 1304 of the lens 132 are aspherical surfaces, the lens 131 is a spherical lens, and the materials of the lens 131 and the lens 132 are optical resin. The lens 132 is a positive lens with a large Abbe number, and the lens 131 is a negative lens with a small Abbe number, and the two lenses are combined to correct the chromatic aberration of the system. In order to reduce the weight, each prism in the prism group 12 is designed with a resin material, and preferably, the surface type of the first optical surface 1206 and the third optical surface 1204 is a free surface, which can effectively correct the aberration of the system caused by off-axis. The compensating prism 123 is invalid for the first display light path, but effectively relieves the design difficulty of the second display light path; the prism 123 and the prism 122 are fixed together by the way of glue bonding. The curved surfaces 1203 and 1202 have similar surface types, and in order to ensure the total internal reflection condition of the light when reaching 1205 for the first time, an air layer of 0.5 mm is reserved between 1203 and 1202.

[0063] As shown in Table 4, in the second display light path in this embodiment, the front surface and the rear surface of the lens 231 are aspherical surfaces, and the material of the lens 231 is optical glass; the use of the aspherical lens effectively corrects the aberration of the system. The remaining lenses 232-235 are spherical glass lenses. Among them, the lens 232 is a positive lens with a large Abbe number, and the lens 233 is a negative lens with a small Abbe number, and the two lenses are bonded to correct the chromatic aberration of the system.

[0064] Table 1: Optical system parameters of the first display light path of the first embodiment

[0065]

[0066]

[0067] Table 2: Free surface coefficients of the first display light path of the first embodiment

[0068]

[0069]

[0070] Table 3: Aspherical surface coefficients of the first display light path of the first embodiment

[0071]

[0072]

[0073] Table 4: Parameters of the second display light path of the first embodiment

[0074] Surface marker Type Radius of curvature Thickness Refractive index Abbe number 2101 Spherical Infinite 17.7 2201 Spherical 200 16 1.53 55.60 2202 Spherical -200 1 2301 Aspherical 30.87 6.9 1.69 53.66 2302 Spherical -147.36 0.3 2303 Spherical 25.72 8.5 1.88 40.8 2304 Spherical -74.89 1 1.84 23.8 2305 Spherical 13.74 2.8 2306 Spherical 22.71 5.4 1.88 40.8 2307 Spherical -65.84 0.5 2308 Spherical -43.28 1 1.85 23.8 2309 Infinite Spherical 5.9 2401 Infinite Spherical 0.7 1.52 64.2 2402 Infinite Figure 8

[0075] Table 5 Aspheric coefficients of the second display light path in the first embodiment

[0076]

[0077] Among the above optical surfaces, the spherical surface satisfies the equation: Where c is the inverse of the radius of curvature and r is the radial distance from a point on the surface.

[0078] The surface formed as an aspheric surface satisfies the equation: c is the inverse of the radius of curvature, r is the radial distance of a point on the surface, k is the quadratic constant, and Ai is the coefficient of the higher-order term.

[0079] The surface of the free-form surface with the shape of XY polynomial satisfies the equation:

[0080]

[0081] Where c is the inverse of the radius of curvature, r is the radial distance of a point on the surface, k is the quadratic constant, and Cj are the polynomial coefficients.

[0082] In this embodiment, the focal length of the first display light path is 17 mm. <f 1<25mm,所述第二显示光路的焦距为20mm<f2<30mm。同时,所述第一显示光路和所述第二显示光路的出瞳距离在15~25mm之间。

[0083] The field of view angles of the two display light paths can be the same or different and can be designed according to the specific display scenario.

[0084] Second embodiment

[0085] like Figure 9 and Figure 10 As shown, in the dual-focal-plane near-eye display optical system provided in the second embodiment, the setting of the first display light path is basically the same as that in the first embodiment; the difference is that there is a difference in the second lens group in the second display light path.

[0086] In this embodiment, the second display light path includes a second micro display 341, a second lens group 331-336, and an equivalent lens group 321. The second micro display 341 and the equivalent lens group 321 are the same as in the first embodiment. The second lens group 331-336 includes six lenses. Compared with the second lens group 23 in the first embodiment, the second lens group 331-336 includes five lenses with similar shapes, and a meniscus negative lens 333 is added between the lens 331 close to the prism group 321 and the positive-negative doublet lens. The meniscus negative lens 333 has a convex surface facing the human eye. In the second lens group, each optical surface 3301-3311 is a spherical surface. For specific parameters, see Table 6.

[0087] Table 6: Second display light path parameters of the second embodiment

[0088]

[0089]

[0090] In the second display light path, the light emitted by the micro display 341 first passes through the second lens group 331-336, then reaches the equivalent lens group 321, and finally exits the exit pupil 3101 and enters the human eye through the surface 3201 of the equivalent lens group. The exit pupil 3101 has the same position and size as the exit pupil 1101.

[0091] Third embodiment

[0092] As shown in Figure 11 and ​ , in the bifocal near-eye display optical system provided by the third embodiment, the first display light path is basically the same as the first embodiment. The difference lies in the second lens group in the second display light path.

[0093] In this embodiment, the second display light path includes a second micro display 441, a second lens group 431-436, and an equivalent lens group 421. The second micro display 441 and the equivalent lens group 421 are the same as in the first embodiment. The second lens group 431-436 includes six lenses. Compared with the second lens group 23 in the first embodiment, the second lens group 431-436 includes five lenses with similar shapes, and a meniscus negative lens 333 is added between the lens 331 close to the prism group 321 and the positive-negative doublet lens. The meniscus negative lens 333 has a convex surface facing the human eye. In the second lens group, each optical surface 3301-3311 is a spherical surface. For specific parameters, see Table 6.

[0094] Table 7: Second display light path parameters of the third embodiment

[0095]

[0096]

[0097] In the second display light path, the light emitted by the micro display 441 first passes through the lens group, wherein the lens surfaces 4301-4311 are all spherical surfaces, and then the light reaches the equivalent lens group 421, and finally the light exits from the surface 4201 of the equivalent lens group, reaches the exit pupil 4101 and enters the human eye. The exit pupil 4101 has the same position and size as the exit pupil 1101.

[0098] In summary, the bifocal near-eye display optical system provided by the application forms display focal planes at different positions through two display light paths; the human eye can switch between the two focal planes, so that the human eye is exercised, thereby preventing and controlling vision. In addition, the focal plane positions of the two display light paths can be regularly changed to exercise the function of the eyes, fully mobilize the potential of the eyes, relieve visual fatigue, improve accommodation speed, increase accommodation amplitude, and effectively improve accommodation lag, insufficient accommodation function, etc.

[0099] By making the above-mentioned bifocal near-eye display optical system into a VR device, different display modes are realized by forming focal planes at different positions through two display light paths. Long-term wearing slowly adjusts the distance between the image and the lens, so that the wearer can slowly adapt to the zooming process, thereby correcting the vision. In addition, by watching VR videos, there will be enough fun, which is helpful for the correction of vision.

Claims

1. A dual-focal-plane near-eye display optical system, characterized in that Comprising: A prism group, a first lens group, and a second lens group. Among them, the prism group includes an auxiliary prism, a main prism, and a compensation prism arranged along the optical axis direction. The main prism includes a first optical surface, a second optical surface, and a third optical surface. The first optical surface serves as the incident surface. The second optical surface is arranged close to the human eye. The third optical surface is arranged far from the human eye and is provided with a beam-splitting film. The auxiliary prism is arranged on the side of the second optical surface, and the compensation prism is arranged on the side of the third optical surface; A first display optical path, including the main prism and the auxiliary prism in the prism group and the first lens group; The first lens group is arranged on the light incident side of the main prism. The first light ray refracted by the first lens group enters the main prism through the first optical surface, undergoes total reflection on the second optical surface, and then is partially reflected by the third optical surface, passes through the second optical surface, and then passes through the auxiliary prism to reach the human eye; The first display optical path has a first display focal plane; A second display optical path, including the prism group and the second lens group; The second lens group is arranged on the side far from the human eye of the prism group, and the optical axis of the second lens group is arranged on the optical axis; The second light ray refracted by the second lens group passes through the compensation prism, the main prism, and the auxiliary prism in sequence to reach the human eye; The second display optical path has a second display focal plane; The positions of the first display focal plane and the second display focal plane are different. The two display focal planes respectively belong to the realization of positive diopter and negative diopter. And, the diopter corresponding to one of the focal planes is -5D to -0D, and the diopter corresponding to the other focal plane is +0D to +5D.

2. The dual-focal-plane near-eye display optical system according to claim 1, wherein: The prism group is equivalent to a lens with a positive optical power for the second display optical path, and the focal length range is: 80mm < f < 300mm.

3. The dual-focal-plane near-eye display optical system according to claim 1, wherein: There is a gap less than 1mm between the main prism and the auxiliary prism, and the main prism and the compensation prism are cemented.

4. The dual-focal-plane near-eye display optical system according to claim 1, wherein: The surface shape of the first optical surface and / or the third optical surface is a free-form surface.

5. The dual-focal-plane near-eye display optical system according to claim 1, wherein: The focal length of the first display optical path is 17mm < f1 < 25mm, and the focal length of the second display optical path is 20mm < f2 < 30mm.

6. The dual-focal-plane near-eye display optical system according to claim 1, wherein: The exit pupil distances of the first display optical path and the second display optical path are between 15 and 25mm.

7. The dual-focal-plane near-eye display optical system according to claim 1, wherein: The position change range of one of the focal planes is within a range not greater than -200mm, and the position change range of the other focal plane is within a range not less than +200mm.

8. The dual-focal-plane near-eye display optical system according to any one of claims 1 to 7, wherein: Further comprising: A first microdisplay for providing the first light ray to the first lens group; And A second microdisplay for providing the second light ray to the second lens group.

9. The dual-focal-plane near-eye display optical system according to claim 8, wherein: The first microdisplay and / or the second microdisplay can move along the direction of the central light of the central field of view to achieve a change in the focal plane position.

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