A single display binocular diopter adjustable near eye display system

Abstract

The application discloses a single-display binocular diopter adjustable near-eye display system, which comprises a display, a light splitting prism, a first imaging display unit and a second imaging display unit, wherein the display is used for emitting imaging light and moving relative to the light splitting prism to realize diopter adjustment; the light splitting prism is used for splitting the imaging light emitted by the display into two paths and corresponding to the imaging display units; each imaging display unit is corresponding to a human eye and comprises a first imaging lens unit, a plane mirror and a curved mirror; the plane mirror is arranged to be inclined to the optical axis of the first imaging lens unit; the mirror surface of the curved mirror far from the human eye is coated with a light splitting film, and the mirror surface close to the human eye is coated with an anti-reflection film. The system realizes binocular viewing by using a single display, which helps to reduce the cost, realize small size and light weight, and has a larger eye movement range and a larger field of view, and the imaging quality is excellent, and the system can adapt to the needs of different vision groups.

Description

Technical Field

[0001] This invention belongs to the field of near-eye display technology, specifically relating to a single-display binocular near-eye display system with adjustable diopter. Background Technology

[0002] With the emergence of virtual reality (VR) and augmented reality (AR), the market for near-eye display devices based on VR or AR modes has also developed rapidly. Near-eye display devices are optical systems that project images directly into the viewer's eyes. They are currently widely used in fields such as movie watching, gaming, education, industry, and medicine, and the corresponding technologies and product performance have been further improved. However, existing near-eye display optical systems still suffer from problems such as heavy weight, large size, small field of view, and low resolution. Furthermore, the cost of a single module is high during mass production, and it is difficult to achieve a larger field of view (FOV) and eye movement range (EYEBOX) with current display specifications. Therefore, to overcome these problems, a single-display binocular diopter-adjustable near-eye display system with a large field of view, high resolution, ultra-thin design, and low cost is proposed. Summary of the Invention

[0003] The purpose of this invention is to address the above-mentioned problems by proposing a single-display binocular diopter adjustable near-eye display system. This system enables binocular viewing using a single display, which helps reduce costs, achieves miniaturization and lightweight design, and provides a larger eye movement range and field of view. It also offers excellent image quality and can meet the needs of people with different vision.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] This invention proposes a single-display binocular diopter-adjustable near-eye display system, comprising a display, a beam splitter, a first imaging display unit, and a second imaging display unit, wherein:

[0006] A display that emits imaging light and moves relative to a beam splitter to adjust diopter;

[0007] A beam splitter is used to split the imaging light emitted by the display into two paths, and the two imaging light paths are incident on the imaging display unit in a one-to-one correspondence.

[0008] Each imaging display unit corresponds to a human eye and includes a first imaging lens unit, a plane mirror, and a curved mirror. The first imaging lens unit includes at least one lens. The plane mirror is tilted relative to the optical axis of the first imaging lens unit. The curved mirror has a beam-splitting coating on the side away from the human eye and an anti-reflective coating on the side closer to the human eye. The curved mirror also satisfies the following conditions:

[0009] 10mm < |f1| < 30mm, 1.2mm <CT1<2mm,42mm<L<50mm,1.8<L / D<2.1;

[0010] Where f1 is the focal length of the curved mirror, CT1 is the thickness of the curved mirror, L is the length of the curved mirror, which is the left-right distance of the curved mirror when worn by the human body, and D is the width of the curved mirror, which is the up-down distance of the curved mirror when worn by the human body.

[0011] The imaging light received by the imaging display unit passes through the first imaging lens unit, is reflected by the plane mirror to the curved mirror, and then reflected by the curved mirror to the human eye. At the same time, external light enters the human eye through the curved mirror.

[0012] Preferably, the imaging display unit further includes a plane mirror imaging unit. The plane mirror imaging unit is tilted relative to the first optical axis with an tilt angle of 30° to 60°. The first optical axis is the line connecting the center of the human eye and the center of the curved mirror. The plane mirror imaging unit includes a plane mirror and has a semi-transparent and semi-reflective coating or a first polarizing unit on the side closer to the curved mirror, and an anti-reflective coating on the side farther from the curved mirror. The first polarizing unit is at least one of a polarizing film, a polarizing reflection film, a phase retardation film, and an anti-reflective film.

[0013] Preferably, the first polarization unit includes a polarizing reflective film, a phase retardation film, and a polarizing film that are sequentially attached.

[0014] Preferably, the first imaging lens unit satisfies -15mm≤f0≤-6mm, where f0 is the focal length of the first imaging lens unit.

[0015] Preferably, the first imaging lens unit includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the light propagation direction. The first lens is a glass spherical lens with negative optical power, the second lens is a glass spherical lens with positive optical power, the third lens is a plastic aspherical lens with negative optical power, and the fourth lens is a glass spherical lens with negative optical power, and satisfies the following conditions:

[0016] 10mm < |f2| < 25mm, 1mm <CT2<3mm,1<CT2 / ET2<1.5;

[0017] 7mm < |f3| < 15mm, 0.5mm <CT3<3mm,0.6<CT3 / ET3<1;

[0018] 10mm < |f4| < 20mm, 0.5mm <CT4<3mm,H / h<3;

[0019] 10mm < |f5| < 20mm, 1mm <CT5<3mm,0.7<CT5 / ET5<1.5;

[0020] Where f2 is the focal length of the first lens, CT2 is the center thickness of the first lens, ET2 is the edge thickness of the first lens, f3 is the focal length of the second lens, CT3 is the center thickness of the second lens, ET3 is the edge thickness of the second lens, f4 is the focal length of the third lens, CT4 is the center thickness of the third lens, H is the maximum thickness of the third lens, H = CT4, h is the minimum thickness of the third lens, f5 is the focal length of the fourth lens, CT5 is the center thickness of the fourth lens, and ET5 is the edge thickness of the fourth lens.

[0021] Preferably, the first imaging lens unit satisfies 10mm≤f0≤20mm, where f0 is the focal length of the first imaging lens unit.

[0022] Preferably, the first imaging lens unit includes a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the direction of light propagation. The fifth lens is a plastic aspherical lens with positive optical power, the sixth lens is a plastic aspherical lens with negative optical power, and the seventh lens is a plastic aspherical lens with positive optical power, and satisfies the following conditions:

[0023] 12mm < |f6| < 15mm, 4mm <CT6<5.5mm,1.8<CT6 / ET6<4;

[0024] 12mm < |f7| < 15mm, 0.7mm <CT7<1.5mm,2<ET7 / CT7<5;

[0025] 12mm < |f8| < 15mm, 4.5mm <CT8<6.2mm,1<CT8 / ET8<3;

[0026] Where f6 is the focal length of the fifth lens, CT6 is the center thickness of the fifth lens, ET6 is the edge thickness of the fifth lens, f7 is the focal length of the sixth lens, CT7 is the center thickness of the sixth lens, ET7 is the edge thickness of the sixth lens, f8 is the focal length of the seventh lens, CT8 is the center thickness of the seventh lens, and ET8 is the edge thickness of the seventh lens.

[0027] Preferably, the single-display binocular diopter adjustable near-eye display system further includes a second imaging lens unit, which includes at least one lens and has a focal length of -130mm≤f≤-100mm. The imaging light emitted by the display passes through the second imaging lens unit and enters the beam splitter.

[0028] Preferably, the mirror surfaces of each lens on the first imaging lens unit are coated with an anti-reflection film and the optical axis is set horizontally.

[0029] Preferably, the surface of the curved mirror is spherical, aspherical, or freeform, and the transmittance-to-reflection ratio of the beam-splitting film on the curved mirror is 1:4 to 1:1, and the reflectivity of the antireflection film on the curved mirror is <1%.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] This near-eye display system achieves binocular viewing with a single display, reducing costs and making it smaller and lighter. With the combined action of the first imaging lens unit and the curved mirror, the virtual display optical path achieves a wider range of eye movement and field of view, resulting in excellent image quality and low distortion. In addition, the refractive power can be varied from 0D to -6D by adjusting the distance between the display and the beam splitter to meet the needs of people with different vision, making it widely applicable. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the single-display binocular diopter adjustable near-eye display system according to Embodiment 1 of the present invention;

[0033] Figure 2 This is a top view of the single-display binocular diopter adjustable near-eye display system of Embodiment 1 of the present invention;

[0034] Figure 3 This is a left view of the single-display binocular diopter adjustable near-eye display system of Embodiment 1 of the present invention;

[0035] Figure 4 This is a cross-sectional view AA of the single-display binocular diopter adjustable near-eye display system of Embodiment 1 of the present invention;

[0036] Figure 5 This is the MTF diagram of Embodiment 1 of the present invention;

[0037] Figure 6 This is a distortion image of Embodiment 1 of the present invention;

[0038] Figure 7 This is a front view of the single-display binocular diopter adjustable near-eye display system of Embodiment 2 of the present invention;

[0039] Figure 8 This is a schematic diagram of the optical path structure of the first imaging display unit or the second imaging display unit in Embodiment 2 of the present invention;

[0040] Figure 9 This is the MTF diagram of Embodiment 2 of the present invention.

[0041] Explanation of reference numerals in the attached figures: 1. Display; 2. Beam splitter prism; 3. First imaging lens unit; 4. Plane mirror; 5. Plane mirror imaging unit; 6. Curved mirror; 7. Human eye; 8. Second imaging lens unit; 31. First lens; 32. Second lens; 33. Third lens; 34. Fourth lens; 35. Fifth lens; 36. Sixth lens; 37. Seventh lens. Detailed Implementation

[0042] 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 some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] It should be noted that when a component is referred to as being "connected" to another component, it can be directly connected to the other component or there may be an intervening component. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application.

[0044] Example 1:

[0045] like Figure 1-6 As shown, a single-display binocular diopter-adjustable near-eye display system includes a display 1, a beam splitter 2, a first imaging display unit, and a second imaging display unit, wherein:

[0046] Display 1 is used to emit imaging light and move relative to beam splitter 2 to adjust diopter.

[0047] The beam splitter 2 is used to split the imaging light emitted by the display 1 into two paths, and the two imaging light paths are incident on the imaging display unit in a one-to-one correspondence.

[0048] Each imaging display unit corresponds to a human eye and includes a first imaging lens unit 3, a plane mirror 4, and a curved mirror 6. The first imaging lens unit 3 includes at least one lens. The plane mirror 4 is tilted relative to the optical axis of the first imaging lens unit 3. The curved mirror 6 has a beam-splitting film on the surface away from the human eye and an anti-reflective film on the surface closer to the human eye. The curved mirror 6 also satisfies the following conditions:

[0049] 10mm < |f1| < 30mm, 1.2mm <CT1<2mm,42mm<L<50mm,1.8<L / D<2.1;

[0050] Among them, f1 is the focal length of the curved mirror 6, CT1 is the thickness of the curved mirror 6, L is the length of the curved mirror 6, that is, the left-right direction distance of the curved mirror 6 when worn by the human body, and D is the width of the curved mirror 6, that is, the up-down direction distance of the curved mirror 6 when worn by the human body;

[0051] After the imaging light rays received by the imaging display unit pass through the first imaging lens unit 3, they are reflected by the plane mirror 4 to the curved mirror 6, and then reflected by the curved mirror 6 to the human eye. At the same time, external light rays enter the human eye through the curved mirror 6.

[0052] Among them, the display 1 (micro display) includes, but is not limited to, one of an LCoS display, a silicon-based OLED display, a micro-LED display, and a DLP display. Each surface of the beam splitter prism 2 is a plane and does not provide optical power for the optical system. The beam splitter prism 2 includes a rectangular block composed of four multi-prisms (such as two triangular prisms and two quadrangular prisms), and is designed with a symmetric structure. Each inclined surface is coated with a beam splitting film, which plays the role of transmitting and reflecting light rays. It is made of high refractive index glass, and satisfies 1.75 < nd < 1.9, where nd is the refractive index. The curved mirror 6 plays the role of reflecting and transmitting light rays, and each mirror surface can be a spherical surface, an aspherical surface, or a free-form surface. The focal length value of the curved mirror 6 within the above range can meet the required virtual image distance, and by reasonably setting the thickness and aspect ratio of the curved mirror 6, thinning and better wearing immersion can be achieved. The surfaces of the plane mirror 4 are all planes and do not provide optical power for the optical system, and play the role of reflecting light rays. For example, a metal reflection film or a dielectric reflection film is coated on one side close to the first imaging lens unit 3.

[0053] The entire system is a symmetric distribution structure, including exactly the same first virtual display optical path and second virtual display optical path, as well as exactly the same third perspective display optical path and fourth perspective display optical path. The two virtual display optical paths share a set of the display 1 and the beam splitter prism 2. Using one display 1 can achieve binocular viewing, reduce the number of displays 1 to achieve cost reduction and miniaturization and light weight, and under the combined action of the first imaging lens unit 3 and the curved mirror 6, the virtual display optical path can achieve a larger eye movement range and field of view.

[0054] In an embodiment, the imaging display unit further includes a plane mirror imaging unit 5. The plane mirror imaging unit 5 is inclined relative to the first optical axis, and the inclination angle is 30° - 60°. The first optical axis is the connection line between the center corresponding to the human eye and the center of the curved mirror 6. The plane mirror imaging unit 5 includes a plane mirror, and a half-transmissive and half-reflective film or a first polarization unit is provided on one side close to the curved mirror 6, and an anti-reflection film is provided on the side far from the curved mirror 6. The first polarization unit is at least one of a polarization film, a polarization reflection film, a phase retardation film, and an anti-reflection film.

[0055] The surfaces of the plane mirrors are all flat and do not provide optical power to the optical system, but play the role of beam splitting. The side of the plane mirror closest to the curved mirror 6 is coated with a semi-transparent and semi-reflective film or a polarizing property film (first polarizing unit).

[0056] In this embodiment, the imaging display unit of the virtual display optical path receives the imaging light, which is then reflected by the plane mirror 4 through the first imaging lens unit 3 to the plane mirror imaging unit 5. The plane mirror imaging unit 5 then reflects the light to the curved mirror 6. The curved mirror 6 then reflects the light, which passes through the plane mirror imaging unit 5 and enters the human eye. Simultaneously, external light passes through the curved mirror 6 and the plane mirror imaging unit 5 sequentially to enter the human eye. In the perspective display optical path, external light also passes through the corresponding curved mirror 6 and the plane mirror imaging unit 5 sequentially to enter the human eye.

[0057] In one embodiment, the first polarization unit includes a polarizing reflective film, a phase retardation film, and a polarizing film that are sequentially attached. The specific combination can be adjusted according to actual needs.

[0058] In one embodiment, the first imaging lens unit 3 satisfies -15mm ≤ f0 ≤ -6mm, where f0 is the focal length of the first imaging lens unit 3. This can improve the system's field of view (FOV) and reduce optical aberrations, especially distortion, at large FOVs.

[0059] In one embodiment, the first imaging lens unit 3 includes a first lens 31, a second lens 32, a third lens 33, and a fourth lens 34 arranged sequentially along the light propagation direction. The first lens 31 is a glass spherical lens with negative optical power, the second lens 32 is a glass spherical lens with positive optical power, the third lens 33 is a plastic aspherical lens with negative optical power, and the fourth lens 34 is a glass spherical lens with negative optical power, and satisfies the following conditions:

[0060] 10mm < |f2| < 25mm, 1mm <CT2<3mm,1<CT2 / ET2<1.5;

[0061] 7mm < |f3| < 15mm, 0.5mm <CT3<3mm,0.6<CT3 / ET3<1;

[0062] 10mm < |f4| < 20mm, 0.5mm <CT4<3mm,H / h<3;

[0063] 10mm < |f5| < 20mm, 1mm <CT5<3mm,0.7<CT5 / ET5<1.5;

[0064] Wherein, f2 is the focal length of the first lens 31, CT2 is the center thickness of the first lens 31, ET2 is the edge thickness of the first lens 31, f3 is the focal length of the second lens 32, CT3 is the center thickness of the second lens 32, ET3 is the edge thickness of the second lens 32, f4 is the focal length of the third lens 33, CT4 is the center thickness of the third lens 33, H is the maximum thickness of the third lens 33, H=CT4, h is the minimum thickness of the third lens 33, f5 is the focal length of the fourth lens 34, CT5 is the center thickness of the fourth lens 34, ET5 is the edge thickness of the fourth lens 34.

[0065] By properly setting the focal length and thickness of each lens, the system's field of view (FOV) can be increased, and optical aberrations, especially distortion, can be reduced under a large FOV, thus greatly improving the imaging quality.

[0066] In one embodiment, the single-display binocular diopter-adjustable near-eye display system further includes a second imaging lens unit 8. The second imaging lens unit 8 includes at least one lens, and the focal length of the second imaging lens unit 8 is -130mm ≤ f ≤ -100mm. The imaging light emitted from the display 1 passes through the second imaging lens unit 8 and enters the beam splitter 2. The CRA angle of the emitted light can be adjusted by the second imaging lens unit 8.

[0067] In one embodiment, each lens on the first imaging lens unit 3 has an anti-reflective coating on its surface and its optical axis is horizontally oriented. The anti-reflective coating increases light energy utilization and reduces stray light. The horizontal direction refers to the left-right direction when the lens is worn by the human body.

[0068] In one embodiment, the surface of the curved mirror 6 is spherical, aspherical, or freeform, and the transmittance-to-reflection ratio of the beam-splitting film on the curved mirror 6 is 1:4 to 1:1, and the reflectivity of the antireflection film on the curved mirror 6 is <1%. Each surface of the curved mirror 6 can be spherical, aspherical, or freeform. For example, to improve the display performance of the optical system and reduce the processing difficulty of the system, both surfaces are designed to be aspherical.

[0069] The working principle of the single-display binocular diopter adjustable near-eye display system in this embodiment:

[0070] The first and second virtual display optical paths are identical, corresponding to the left and right eyes of the human, respectively. The imaging process of the virtual display optical path is as follows: Display 1 emits imaging light, which is split into two paths by beam splitter prism 2. These paths are incident on the imaging display unit one-to-one. The imaging light received by the imaging display unit passes through the first imaging lens unit 3, is reflected by plane mirror 4 to plane mirror imaging unit 5, and then reflected by plane mirror imaging unit 5 to curved mirror 6. Curved mirror 6 reflects the light through plane mirror imaging unit 5 to the human eye. That is, a portion of the imaging light is split and deflected by beam splitter prism 2 before entering the first imaging lens unit 3. Each mirror in the first imaging lens unit 3 can be coated with an anti-reflection film to increase light energy utilization and reduce possible stray light. After reaching plane mirror 4, the light is deflected downwards, passes through plane mirror imaging unit 5, and a portion of the light is reflected to curved mirror 6, then reflected back to plane mirror imaging unit 5 and passes through, finally entering the human eye.

[0071] The third perspective display light path and the fourth perspective display light path are the same, and they also correspond to the left and right eyes of a person, respectively. The imaging process of the perspective display light path is as follows: external light first passes through the outer surface of the corresponding curved mirror 6 (i.e. the mirror surface away from the plane mirror imaging unit 5), and the light is lost due to reflection at the inner surface (i.e. the mirror surface close to the plane mirror imaging unit 5). The transmitted light continues to propagate into the plane mirror imaging unit 5 and passes through it, and finally enters the human eye.

[0072] The following detailed description, through specific embodiments, is provided to aid understanding.

[0073] In this embodiment, the first virtual display optical path is formed by display 1, beam splitter 2, and first imaging display unit; the second virtual display optical path is formed by display 1, beam splitter 2, and second imaging display unit. The two virtual display optical paths share a single set of display 1 and beam splitter 2. The third perspective display optical path is formed by the plane mirror imaging unit 5 of the first imaging display unit and curved mirror 6; the fourth perspective display optical path is formed by the plane mirror imaging unit 5 of the second imaging display unit and curved mirror 6. A semi-transparent, semi-reflective coating is provided on the plane mirror of the plane mirror imaging unit 5 near the curved mirror 6. The surface of the curved mirror 6 near the human eye is convex, and the surface away from the human eye is concave. The aperture is the position of the human eye. By adjusting the distance between display 1 and beam splitter 2, the refractive power can be varied from 0D to -6D to meet the needs of people with different visual acuity.

[0074] The parameters of each optical element are shown in Table 1 below:

[0075] Table 1

[0076] aperture spherical unlimited \ \ \ refraction Plane Mirror-01 spherical unlimited 1 1.55 55.90 refraction Plane Mirror-02 spherical unlimited 16.5 \ \ refraction Curved mirror 6-02 aspherical -38.1 -16.5 \ \ reflection Plane Mirror-02 spherical unlimited 17 \ \ reflection Plane mirror 4-02 spherical unlimited -8 \ \ reflection Fourth Lens 34-01 spherical -13.4 -3.03 1.9 31.32 refraction Fourth Lens 34-02 spherical 697.9 -1.41 refraction Third Lens 33-01 aspherical -14.55 -2.6 1.55 55.90 refraction Third Lens 33-02 aspherical 22.4 -0.2 \ \ refraction Second lens 32-01 spherical 26.8 -1 1.95 17.9 refraction Second lens 32-02 spherical -12.6 -1.5 refraction First lens 31-01 spherical -34.8 -3.3 1.9 31.32 refraction First lens 31-02 spherical 14.4 -4.5 refraction Beam Spectrometer-01 spherical unlimited -6.5 1.84 23.78 refraction Spectrometer Prism-02 spherical unlimited 6.5 1.84 23.78 reflection Spectrometer Prism-03 spherical unlimited 2 refraction monitor spherical unlimited \ \ \ refraction

[0077] In Table 1, beam splitter-01 represents the exit surface of the beam splitter, beam splitter-02 represents the inclined plane where the beam splitter's beam splitting film is located, beam splitter-03 represents the incident surface of the beam splitter, plane mirror-01 represents the surface of the plane mirror closest to the human eye, plane mirror-02 represents the surface of the plane mirror furthest from the human eye, fourth lens 34-01 represents the exit surface of the fourth lens 34, fourth lens 34-02 represents the incident surface of the fourth lens 34, and third lens 33-01 represents the exit surface of the third lens 33. The third lens 33-02 represents the incident surface of the third lens 33, the second lens 32-01 represents the exit surface of the second lens 32, the second lens 32-02 represents the incident surface of the second lens 32, the first lens 31-01 represents the exit surface of the first lens 31, the first lens 31-02 represents the incident surface of the first lens 31, the plane mirror 4-02 represents the mirror surface of the plane mirror near the first imaging lens unit 3, and the curved mirror 6-02 represents the mirror surface of the curved mirror 6 near the human eye.

[0078] Aspherical surfaces satisfy the following equations:

[0079]

[0080] Where z is the sag, c is the reciprocal of the radius of curvature, r is the radial distance from a point on the mirror surface, k is the quadratic surface constant, and A, B, C, D, E, F, G, H, and I are coefficients of higher-order terms.

[0081] Aspherical coefficients are shown in Table 2:

[0082] Table 2

[0083] Conic Constant(k) 0.2195 3.014 -60.0942 4th Order Coefficient (A) 1.5828e-06 0.0003326 0.00013495 6th Order Coefficient (B) -7.7566e-09 -2.0619e-05 2.07e-05 8th Order Coefficient (C) 5.5688e-11 4.0317e-06 -4.1115e-06 10th Order Coefficient (D) -1.6578e-13 -3.6408e-07 3.4808e-07 12th Order Coefficient (E) 1.8095e-16 2.0069e-08 -1.7210e-08 14th Order Coefficient (F) 0 -6.8986e-10 5.3212e-10 16th Order Coefficient (G) 0 1.4663e-11 -9.9728e-12 18th Order Coefficient (H) 0 -1.7631e-13 1.0287e-13 20th Order Coefficient (I) 0 9.2036e-16 -4.4346e-16

[0084] Based on the above data, such as Figure 5 , 6 As shown, the single-display binocular diopter adjustable near-eye display system of this embodiment has an MTF>0.4 and distortion<1% at 30lp / mm, with excellent imaging quality, a field of view (FOV) of 45°~50°, and an eye movement range (EYEBOX) of 10*6~12*8.

[0085] Example 2:

[0086] like Figure 7-9 As shown, a single-display binocular diopter-adjustable near-eye display system includes a display 1, a beam splitter 2, a first imaging display unit, and a second imaging display unit, wherein:

[0087] Display 1 is used to emit imaging light and move relative to beam splitter 2 to adjust diopter.

[0088] A beam-splitting prism 2 is used to split the imaging light emitted by the display 1 into two paths, and the two paths of imaging light are incident on the imaging display units one by one;

[0089] Each imaging display unit corresponds to the human eye 7 one by one, and includes a first imaging lens unit 3, a plane mirror 4 and a curved mirror 6. The first imaging lens unit 3 includes at least one lens. The plane mirror 4 is inclined with respect to the optical axis of the first imaging lens unit 3. A beam-splitting film is coated on the mirror surface of the curved mirror 6 far from the human eye 7, and an anti-reflection film is coated on the mirror surface close to the human eye 7. And the curved mirror 6 satisfies the following conditions:

[0090] 10mm < |f1| < 30mm, 1.2mm < CT1 < 2mm, 42mm < L < 50mm, 1.8 < L / D < 2.1;

[0091] Where, f1 is the focal length of the curved mirror 6, CT1 is the thickness of the curved mirror 6, L is the length of the curved mirror 6, that is, the left-right direction distance when worn by the human body, and D is the width of the curved mirror 6, that is, the up-down direction distance when worn by the human body;

[0092] After the imaging light received correspondingly by the imaging display unit passes through the first imaging lens unit 3, it is reflected by the plane mirror 4 to the curved mirror 6, and then reflected by the curved mirror 6 to the human eye 7. At the same time, the external light passes through the curved mirror 6 and enters the human eye 7.

[0093] Among them, the display 1 (micro display) includes but is not limited to one of an LCoS display, a silicon-based OLED display, a micro-LED display and a DLP display. Each surface of the beam-splitting prism 2 is a plane and does not provide optical power for the optical system. The beam-splitting prism 2 includes a rectangular block composed of four multi-prisms (such as two triangular prisms and two quadrangular prisms), and is designed with a symmetric structure. Each inclined surface is coated with a beam-splitting film, which plays the role of transmitting and reflecting light. The material is high-refractive-index glass, satisfying 1.75 < nd < 1.9, and nd is the refractive index. The curved mirror 6 plays the role of reflecting and transmitting light, and each mirror surface can be a spherical surface, an aspherical surface or a free-form surface. The focal length value of the curved mirror 6 within the above range can meet the required virtual image distance, and by reasonably setting the thickness and aspect ratio of the curved mirror 6, lightweight and better wearing immersion can be achieved. The surfaces of the plane mirror 4 are all planes and do not provide optical power for the optical system, and play the role of reflecting light. For example, a metal reflection film or a dielectric reflection film is coated on the side close to the first imaging lens unit 3.

[0094] The entire system has a symmetrical distribution structure, including identical first and second virtual display optical paths, as well as identical third and fourth perspective display optical paths. The two virtual display optical paths share a set of displays 1 and beam splitters 2. Binocular viewing can be achieved using only one display 1, reducing the number of displays 1 to lower costs and achieve miniaturization and weight reduction. Furthermore, the combined effect of the first imaging lens unit 3 and the curved mirror 6 enables the virtual display optical path to achieve a wider eye movement range and field of view.

[0095] In one embodiment, the first imaging lens unit 3 satisfies 10mm ≤ f0 ≤ 20mm, where f0 is the focal length of the first imaging lens unit 3. This can improve the system's field of view (FOV) and reduce optical aberrations, especially distortion, at large FOVs.

[0096] In one embodiment, the first imaging lens unit 3 includes a fifth lens 35, a sixth lens 36, and a seventh lens 37 arranged sequentially along the light propagation direction. The fifth lens 35 is a plastic aspherical lens with positive optical power, the sixth lens 36 is a plastic aspherical lens with negative optical power, and the seventh lens 37 is a plastic aspherical lens with positive optical power, and satisfies the following conditions:

[0097] 12mm < |f6| < 15mm, 4mm <CT6<5.5mm,1.8<CT6 / ET6<4;

[0098] 12mm < |f7| < 15mm, 0.7mm <CT7<1.5mm,2<ET7 / CT7<5;

[0099] 12mm < |f8| < 15mm, 4.5mm <CT8<6.2mm,1<CT8 / ET8<3;

[0100] Where f6 is the focal length of the fifth lens 35, CT6 is the center thickness of the fifth lens 35, ET6 is the edge thickness of the fifth lens 35, f7 is the focal length of the sixth lens 36, CT7 is the center thickness of the sixth lens 36, ET7 is the edge thickness of the sixth lens 36, f8 is the focal length of the seventh lens 37, CT8 is the center thickness of the seventh lens 37, ET8 is the edge thickness of the seventh lens 37.

[0101] By properly setting the focal length and thickness of each lens, the system's field of view (FOV) can be increased, and optical aberrations, especially distortion, can be reduced under a large FOV, thus greatly improving the imaging quality.

[0102] In one embodiment, the single-display binocular diopter-adjustable near-eye display system further includes a second imaging lens unit 8. The second imaging lens unit 8 includes at least one lens, and the focal length of the second imaging lens unit 8 is -130mm ≤ f ≤ -100mm. The imaging light emitted from the display 1 passes through the second imaging lens unit 8 and enters the beam splitter 2. The CRA angle of the emitted light can be adjusted by the second imaging lens unit 8.

[0103] In one embodiment, each lens on the first imaging lens unit 3 has an anti-reflective coating on its surface and its optical axis is horizontally oriented. The anti-reflective coating increases light energy utilization and reduces stray light. The horizontal direction refers to the left-right direction when the lens is worn by the human body.

[0104] In one embodiment, the surface of the curved mirror 6 is spherical, aspherical, or freeform, and the transmittance-to-reflection ratio of the beam-splitting film on the curved mirror 6 is 1:4 to 1:1, and the reflectivity of the antireflection film on the curved mirror 6 is <1%. Each surface of the curved mirror 6 can be spherical, aspherical, or freeform. For example, to improve the display performance of the optical system and reduce the processing difficulty of the system, both surfaces are designed to be aspherical.

[0105] The working principle of the single-display binocular diopter adjustable near-eye display system in this embodiment:

[0106] The first and second virtual display optical paths are identical, corresponding to the left and right eyes of the human, respectively. The imaging process of the virtual display optical paths is as follows: Display 1 emits imaging light, which is split into two paths by beam splitter prism 2, and incident on the imaging display unit one-to-one. The imaging light received by the imaging display unit passes through the first imaging lens unit 3, and is reflected by plane mirror 4 to curved mirror 6. Curved mirror 6 then reflects the light to the human eye 7. That is, a portion of the imaging light is split and deflected by beam splitter prism 2 before entering the first imaging lens unit 3. Each mirror surface in each lens of the first imaging lens unit 3 can be coated with an anti-reflection film to increase light energy utilization and reduce possible stray light. After the light reaches plane mirror 4, it is deflected downwards and reflected to curved mirror 6, and then reflected back to the human eye 7 by curved mirror 6.

[0107] The third perspective display light path and the fourth perspective display light path are the same, and they also correspond to the left and right eyes of a person, respectively. The imaging process of the perspective display light path is as follows: external light first passes through the outer surface of the corresponding curved mirror 6 (i.e. the mirror surface away from the human eye 7), and the light is lost due to reflection at the inner surface (i.e. the mirror surface close to the human eye 7), while the transmitted light continues to propagate into the human eye 7.

[0108] The following detailed description, through specific embodiments, is provided to aid understanding.

[0109] The first virtual display optical path in this embodiment is formed by the display 1, the beam splitter prism 2, and the first imaging display unit. The second virtual display optical path is formed by the display 1, the beam splitter prism 2, and the second imaging display unit. The two virtual display optical paths share a set of the display 1 and the beam splitter prism 2. The third perspective display optical path is formed by the curved mirror 6 of the first imaging display unit, and the fourth perspective display optical path is formed by the curved mirror 6 of the second imaging display unit. The second imaging lens unit 8 is located between the display 1 and the beam splitter prism 2 and is a shared structure for the two virtual display optical paths. It includes an eighth lens. The incident surface of the eighth lens is concave, and the exit surface is convex, and it satisfies 1.5 < CT9 < 3, 1.5 < CT9 / ET9 < 3, where CT9 is the central thickness of the eighth lens and ET9 is the edge thickness of the eighth lens. The mirror surface of the curved mirror 6 close to the human eye 7 is convex, and the mirror surface far from the human eye 7 is concave. The aperture stop is at the position of the human eye 7. By adjusting the distance between the display 1 and the beam splitter prism 2, the diopter change from 0D to -6D can be achieved to meet the needs of different vision populations.

[0110] In this embodiment, the plane mirror imaging unit 5 is cancelled relative to Embodiment 1. On the one hand, it can completely eliminate the stray light problem caused by the lower part of the human eye (in Embodiment 1, the external light enters the human eye under the reflection of the plane mirror imaging unit 5 to generate stray light). On the other hand, it can improve the exit pupil light efficiency and is beneficial to further reduce costs while achieving thinness and lightness. The mirror surfaces of the curved mirror 6 adopt free-form surfaces and have a larger FOV.

[0111] The parameters of each optical element are shown in Table 3 below:

[0112] Table 3

[0113]

[0114]

[0115] The aspherical surface type satisfies the following equation:

[0116]

[0117] Among them, z is the sagittal height, c is the reciprocal of the radius of curvature, r is the radial distance of a point on the mirror surface, k is the conic constant, and A, B, C, D, E, F, G, H, I are the high-order term coefficients.

[0118] The aspherical coefficients are shown in Table 4 (the equation coefficient terms not shown in the table are defaulted to 0):

[0119] Table 4

[0120] The XY polynomial surface type satisfies the following equation:

[0121]

[0122] Where Z is the sagittal height, K is the quadratic surface constant, K = 1.2, X is the sagittal plane direction coordinate, Y is the meridional plane direction coordinate, m and n represent the order and take values ​​from 0 to 10, C j For monomial X m Y n The coefficients are shown in Table 5, where C2 is X. 1 and Y 0 The coefficient for the corresponding column is 0, and the same applies to the others.

[0123] The coefficients of the XY polynomial are shown in Table 5:

[0124] Table 5

[0125]

[0126]

[0127] Based on the above data, such as Figure 9 As shown, the single-display binocular diopter adjustable near-eye display system of this embodiment has an MTF>0.2 at 30lp / mm, excellent imaging quality, a field of view (FOV) of 50°~55°, and an eye movement range (EYEBOX) of 10*6~12*8.

[0128] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0129] The embodiments described above are merely specific and detailed examples of the embodiments described in this application, and should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the appended claims.

Claims

1. A single-display binocular diopter-adjustable near-eye display system, characterized in that: The single-display binocular diopter adjustable near-eye display system consists of a display (1), a beam splitter (2), a first imaging display unit, and a second imaging display unit, wherein: The display (1) is used to emit imaging light and move relative to the beam splitter (2) to achieve diopter adjustment; The beam splitter (2) is used to split the imaging light emitted by the display (1) into two paths, and the two imaging light paths are incident on the imaging display unit in a one-to-one correspondence. Each of the imaging display units corresponds to a human eye and includes a first imaging lens unit (3), a plane mirror (4), and a curved mirror (6). The plane mirror (4) is tilted relative to the optical axis of the first imaging lens unit (3). The curved mirror (6) has a beam-splitting film on the surface away from the human eye and an anti-reflective film on the surface close to the human eye. The curved mirror (6) satisfies the following conditions: 10mm < |f1| < 30mm, 42mm <L<50mm,1.8<L / D<2.1; Wherein, f1 is the focal length of the curved mirror (6), L is the length of the curved mirror (6), that is, the left-right distance of the curved mirror (6) when worn by the human body, and D is the width of the curved mirror (6), that is, the up-down distance of the curved mirror (6) when worn by the human body. The first imaging lens unit (3) is composed of a first lens (31), a second lens (32), a third lens (33), and a fourth lens (34) arranged sequentially along the direction of light propagation. The first lens (31) is a biconvex glass spherical lens with positive optical power, the second lens (32) is a biconcave glass spherical lens with negative optical power, the third lens (33) is a biconvex plastic aspherical lens with positive optical power, and the fourth lens (34) is a biconvex glass spherical lens with positive optical power, and satisfies the following conditions: 10mm < |f2| < 25mm, 1 <CT2 / ET2<1.5; 7mm < |f3| < 15mm, 0.5mm <CT3<3mm,0.6<CT3 / ET3<1; 10mm < |f4| < 20mm, 0.5mm <CT4<3mm,H / h<3; 10mm < |f5| < 20mm, 0.7 <CT5 / ET5<1.5; Wherein, f2 is the focal length of the first lens (31), CT2 is the center thickness of the first lens (31), ET2 is the edge thickness of the first lens (31), f3 is the focal length of the second lens (32), CT3 is the center thickness of the second lens (32), ET3 is the edge thickness of the second lens (32), f4 is the focal length of the third lens (33), CT4 is the center thickness of the third lens (33), H is the maximum thickness of the third lens (33), H=CT4, h is the minimum thickness of the third lens (33), f5 is the focal length of the fourth lens (34), CT5 is the center thickness of the fourth lens (34), ET5 is the edge thickness of the fourth lens (34); The imaging light received by the imaging display unit passes through the first imaging lens unit (3), is reflected by the plane mirror (4) to the curved mirror (6), and then reflected by the curved mirror (6) to the human eye. At the same time, external light passes through the curved mirror (6) and enters the human eye.

2. The single-display binocular diopter-adjustable near-eye display system as described in claim 1, characterized in that: The imaging display unit further includes a plane mirror imaging unit (5), which is tilted relative to the first optical axis at an angle of 30° to 60°. The first optical axis is the line connecting the center of the human eye and the center of the curved mirror (6). The plane mirror imaging unit (5) includes a plane mirror and has a semi-transparent and semi-reflective film or a first polarizing unit on the side closer to the curved mirror (6) and an anti-reflective film on the side away from the curved mirror (6). The first polarizing unit is at least one of a polarizing film, a polarizing reflection film, a phase retardation film, and an anti-reflective film.

3. The single-display binocular diopter-adjustable near-eye display system as described in claim 2, characterized in that: The first polarization unit includes a polarizing reflective film, a phase retardation film, and a polarizing film that are sequentially attached.

4. The single-display binocular diopter-adjustable near-eye display system as described in claim 1, characterized in that: The first imaging lens unit (3) satisfies 6mm≤f0≤15mm, where f0 is the focal length of the first imaging lens unit (3).

5. The single-display binocular diopter-adjustable near-eye display system as described in claim 1, characterized in that: Each lens on the first imaging lens unit (3) has an anti-reflection coating on its surface and its optical axis is set horizontally.

6. The single-display binocular diopter-adjustable near-eye display system as described in claim 1, characterized in that: The surface of the curved mirror (6) is spherical, aspherical or free-form, and the transmittance-to-reflection ratio of the beam splitter on the curved mirror (6) is 1:4 to 1:1, and the reflectivity of the antireflection coating on the curved mirror (6) is <1%.

Images