Near-eye optical system and head-mounted display device

Abstract

The embodiment of the invention provides a near-eye optical system and head-mounted display equipment. The near-eye optical system comprises a first optical element, a polarization reflection element, a phase retarder, a second optical element and a light splitting element which are arranged along the same optical axis; the first optical element comprises at least one lens; the second optical element comprises a first lens and a second lens, and at least one lens in the second optical element can move along the optical axis; the second optical element satisfies 0 < abs (phi1 * n1 * v2 / phi2 * n2 * v1) < = 10, phi1, n1 and v1 are respectively the focal power, the refractive index and the Abbe number of the first lens, and phi2, n2 and v2 are respectively the focal power, the refractive index and the Abbe number of the second lens.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical imaging technology, and more specifically, to a near-eye optical system and a head-mounted display device. Background Art

[0002] VR optical solutions have high requirements for chromatic aberration and distortion, and currently mainly use software pre-correction. However, software pre-correction will increase the power consumption of the optical system. In particular, when the field of view of the optical system is relatively large, without software pre-correction, the requirements for the optical solution will be stricter, which will greatly increase the difficulty and cost of production. Summary of the invention

[0003] The purpose of this application is to provide a new technical solution for a near-eye optical system and a head-mounted display device.

[0004] In a first aspect, the present application provides a near-eye optical system. The near-eye optical system comprises a first optical element, a polarization reflection element, a phase retarder, a second optical element and a beam splitter arranged along the same optical axis;

[0005] The first optical element comprises at least one lens;

[0006] The second optical element comprises a first lens and a second lens, and at least one lens of the second optical element is movable along the optical axis;

[0007] The second optical element satisfies: 0<abs(φ1*n1*v2 / φ2*n2*v1)≤10, wherein φ1, n1, v1 are respectively the optical focal length, refractive index and Abbe number of the first lens, and φ2, n2, v2 are respectively the optical focal length and refractive index Abbe number of the second lens.

[0008] Optionally, the optical power φ1 of the first lens is positive, and the optical power φ2 of the second lens is negative.

[0009] Optionally, the total optical power of the second optical element is positive.

[0010] Optionally, the optical power φ of the first optical element is positive.

[0011] Optionally, the first optical element is a single third lens, the optical power of the third lens is φ, and φ is positive.

[0012] Optionally, the first optical element and the second optical element satisfy the following relationship:

[0013] 0<φ / (φ+φ1+φ2)<1.

[0014] Optionally, the near-eye optical system further comprises a display, wherein the display is located on a side of the second optical element facing away from the first optical element, and the display can emit light for imaging display.

[0015] Optionally, the near-eye optical system further includes a fourth lens, and the fourth lens is located between the first lens and the display;

[0016] The first optical element is a third lens;

[0017] The first lens and the second lens are located between the fourth lens and the third lens in sequence, and the first lens and the second lens are configured to be movable along the optical axis.

[0018] Optionally, the display is configured to emit circularly polarized light or natural light;

[0019] In the case that the light emitted by the display is natural light, a superimposed element is disposed on the light emitting surface of the display to convert the natural light into circularly polarized light, and the superimposed element at least includes a phase delay plate and a linear polarizer.

[0020] Optionally, the light splitting element is disposed on a surface of the first lens close to the display;

[0021] The phase retarder and the polarized reflective element are stacked and arranged on a surface of the second lens away from the display.

[0022] Optionally, the near-eye optical system further includes a polarizer, which is disposed on a side of the polarizing reflective element away from the phase retarder, and the polarizer, the polarizing reflective element and the phase retarder are stacked to form a composite film material.

[0023] Optionally, the absolute value of distortion of the near-eye optical system is less than 4%, and the maximum chromatic aberration value is less than 20 μm.

[0024] In a second aspect, the present application provides a head mounted display device. The head mounted display device comprises:

[0025] a housing; and

[0026] A near-eye optical system as described in the first aspect.

[0027] The beneficial effects of this application are:

[0028] According to the near-eye optical system provided in the embodiment of the present application, through the reasonable layout of the optical structure and the reasonable constraints on the optical parameters of the movable second optical element therein, the optical effects of low distortion, low chromatic aberration and variable focus can be achieved.

[0029] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0031] Figure 1 One of the structural schematic diagrams of the near-eye optical system provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of the arrangement of the composite membrane material provided in the embodiment of the present application;

[0033] Figure 3 One of the dot array diagrams of the near-eye optical system provided in Example 1 of the present application;

[0034] Figure 4 One of the modulation transfer function MTF curves of the near-eye optical system provided in Example 1 of the present application;

[0035] Figure 5 One of the field curvature and distortion diagrams of the near-eye optical system provided in Example 1 of the present application;

[0036] Figure 6 One of the vertical axis chromatic aberration diagrams of the near-eye optical system provided in Example 1 of the present application;

[0037] Figure 7 The second dot array diagram of the near-eye optical system provided in Example 1 of the present application;

[0038] Figure 8 A second modulation transfer function MTF curve diagram of the near-eye optical system provided in Example 1 of the present application;

[0039] Fig. 9 The second diagram of field curvature and distortion of the near-eye optical system provided in Example 1 of the present application;

[0040] Fig.10 The second vertical axis chromatic aberration diagram of the near-eye optical system provided in Example 1 of the present application;

[0041] Fig.11 One of the dot array diagrams of the near-eye optical system provided in Example 2 of the present application;

[0042] Fig.12 One of the modulation transfer function MTF curves of the near-eye optical system provided in Example 2 of the present application;

[0043] Fig.13One of the field curvature and distortion diagrams of the near-eye optical system provided in Example 2 of the present application;

[0044] Fig.14 One of the vertical axis chromatic aberration diagrams of the near-eye optical system provided in Example 2 of the present application;

[0045] Fig.15 The second dot array diagram of the near-eye optical system provided in Example 2 of the present application;

[0046] Fig.16 A second modulation transfer function MTF curve diagram of the near-eye optical system provided in Example 2 of the present application;

[0047] Fig.17 The second diagram of field curvature and distortion of the near-eye optical system provided in Example 2 of the present application;

[0048] Fig.18 The second vertical axis chromatic aberration diagram of the near-eye optical system provided in Example 2 of the present application;

[0049] Fig.19 The second structural schematic diagram of the near-eye optical system provided in the embodiment of the present application;

[0050] Fig. 20 One of the dot array diagrams of the near-eye optical system provided in Example 3 of the present application;

[0051] Fig.21 One of the modulation transfer function MTF curves of the near-eye optical system provided in Example 3 of the present application;

[0052] Fig. 22 One of the field curvature and distortion diagrams of the near-eye optical system provided in Example 3 of the present application;

[0053] Fig.23 One of the vertical axis chromatic aberration diagrams of the near-eye optical system provided in Example 3 of the present application;

[0054] Fig.24 The second dot array diagram of the near-eye optical system provided in Example 3 of the present application;

[0055] Fig.25 A second modulation transfer function MTF curve diagram of the near-eye optical system provided in Example 3 of the present application;

[0056] Fig.26 The second diagram of field curvature and distortion of the near-eye optical system provided in Example 3 of the present application;

[0057] Fig. 27 This is the second vertical axis chromatic aberration diagram of the near-eye optical system provided in Example 3 of the present application.

[0058] Description of reference numerals:

[0059] 100, a first optical element; 200, a second optical element;

[0060] 1. Display; 2. Screen protection element; 3. First lens; 4. Second lens; 5. Third lens; 6. Human eye; 7. Polarized reflection element; 8. Phase retarder; 9. Spectral element; 10. Fourth lens; 11. Polarizer; 12. Anti-reflection film. DETAILED DESCRIPTION

[0061] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0062] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0063] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0064] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0065] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0066] The near-eye optical system and the head-mounted display device provided in the embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0067] According to one aspect of an embodiment of the present application, a near-eye optical system is provided, and the near-eye optical system is applicable to a wearable device. The wearable device may be a head mounted display (HMD), such as a VR head mounted display. The VR head mounted display device includes, for example, VR smart glasses or a VR smart helmet, and the form of the head mounted display device is not specifically limited in the embodiment of the present application.

[0068] The near-eye optical system proposed in the embodiment of the present application, see Figure 1, the near-eye optical system includes a first optical element 100, a polarizing reflection element 7, a phase retarder 8, a second optical element 200 and a beam splitter 9 arranged along the same optical axis. The first optical element 100 includes at least one lens. The second optical element 200 includes a first lens 3 and a second lens 4, and at least one of the second optical elements can move along the optical axis; the second optical element 200 also satisfies: 0<abs(φ1*n1*v2 / φ2*n2*v1)≤10, wherein φ1, n1, v1 are respectively the optical power, refractive index and Abbe number of the first lens 3, and φ2, n2, v2 are respectively the optical power and refractive index Abbe number of the second lens 4.

[0069] According to the near-eye optical system provided by the above embodiment of the present application, from the perspective of optical architecture, it includes a first optical element 100 and a second optical element 200 arranged in sequence along the same optical axis, wherein the second optical element 200 is, for example, located on a side close to the screen, and the first optical element 100 is, for example, located on a side close to the human eye 6, see Figure 1 ; Moreover, the spectroscopic element 9, the phase retarder 8 and the polarized reflection element 7 are also introduced into the near-eye optical system, so that a folded light path can be formed on the side close to the screen, and the light incident into the second optical element 200 can be folded back and emitted to the human eye 6 through the first optical element 100 for imaging. The introduction of the folded light path can ensure good imaging quality while reducing the size of the entire near-eye optical system along the optical axis.

[0070] In the near-eye optical system provided in the above embodiment, the second optical element 200 is located on the side away from the human eye 6, and the second optical element 200 may include a first lens 3 and a second lens 4, and the two optical lenses should satisfy the constraint condition of: 0<abs(φ1*n1*v2 / φ2*n2*v1)≤10, wherein φ1, n1, v1 are respectively the focal length, refractive index and Abbe number of the first lens 3, and φ2, n2, v2 are respectively the focal length and refractive index Abbe number of the second lens 4. The optical parameter constraint conditions of the second optical element 200 provided above can well correct the chromatic aberration and distortion of the imaging, so that the formed near-eye optical system has the optical performance of low chromatic aberration and low distortion.

[0071] That is to say, the near-eye optical system provided in the embodiment of the present application has optical performance of low chromatic aberration and low distortion, which eliminates the need to use software to perform imaging correction.

[0072] According to the near-eye optical system provided by the above embodiment of the present application, at least part of the lenses in the second optical element 200 can move away from or closer to the first optical element 100 along the optical axis, thereby achieving a variable focus effect of the near-eye optical system. In this way, users with different vision can use the near-eye optical system and can all obtain a good visual experience.

[0073] The near-eye optical system provided in the embodiment of the present application is shown in FIG. Figure 1 As the second optical element 200 moves along the optical axis, no matter where the second optical element 200 moves to, even if it moves to two extreme positions of diopter, an image with low chromatic aberration and low distortion can be obtained.

[0074] See also Figure 5 and Fig. 9 As shown in FIG. 1 , the absolute value of the distortion of the near-eye optical system provided by the embodiment of the present application is less than 4%. Figure 6 and Fig.10 As shown, the maximum chromatic aberration value of the near-eye optical system provided by the embodiment of the present application is less than 20 μm.

[0075] It should be noted that the second optical element 200 includes but is not limited to two optical lenses, and a larger number of optical lenses, such as three optical lenses, can be provided as needed.

[0076] Specifically, the second optical element 200 may be composed of three optical lenses. Fig.19 , wherein the fourth lens 10 is a newly added lens.

[0077] The driving force for driving the lens in the second optical element 200 to move may be realized by an external driving mechanism or by manual driving, which is not limited in the present application.

[0078] The number of optical lenses included in the first optical element 100 can be adjusted according to the needs of specific optical imaging, but at least one lens should be used in the first optical element 100.

[0079] The near-eye optical system provided in the embodiment of the present application can achieve a larger field of view angle under the premise of miniaturized design, and at the same time can have an optical effect of low chromatic aberration and low distortion, and can also achieve a zoom effect.

[0080] According to the near-eye optical system provided in the embodiment of the present application, through the reasonable layout of the optical structure and the reasonable constraints on the optical parameters of the movable second optical element 200 therein, the optical effects of low distortion, low chromatic aberration and variable focus can be achieved.

[0081] The near-eye optical system provided in the above-mentioned embodiments of the present application is a folded optical path.

[0082] The light splitting element 9 can allow a portion of light to be transmitted and another portion of light to be reflected.

[0083] The light splitting element 9 is, for example, a semi-transmissive and semi-reflective film.

[0084] It should be noted that the reflectivity and transmittance of the light splitting element 9 can be flexibly adjusted according to specific needs, and this is not limited in the embodiments of the present application.

[0085] The phase retarder 8 is, for example, a quarter wave plate.

[0086] Of course, the phase retarder 8 can be set to other phase retarder plates, such as a half-wave plate, etc. as needed.

[0087] The phase retarder 8 can be used to change the polarization state of light, for example, to convert linearly polarized light into circularly polarized light, or to convert circularly polarized light into linearly polarized light.

[0088] The polarized reflective element 7 is a polarized reflector that reflects horizontal linear polarized light and transmits vertical linear polarized light, or a polarized reflector that reflects linear polarized light at any other specific angle and transmits linear polarized light perpendicular to the angle.

[0089] In the embodiment of the present application, the phase retarder 8 and the polarized reflective element 7 cooperate with each other to analyze and transmit the light.

[0090] It should be emphasized that the optical elements such as the beam splitter 9, the phase retarder 8 and the polarization reflection element 7 form a folded light path on the side away from the human eye 6. The layout positions of the above-mentioned optical elements in the lens group are relatively flexible, but it should be ensured that the phase retarder 8 is between the beam splitter 9 and the polarization reflection element 7.

[0091] In some examples of the present application, the optical power φ1 of the first lens 3 is positive, and the optical power φ2 of the second lens 4 is negative.

[0092] According to the near-eye optical system provided in the embodiment of the present application, the second optical element 200 on the side away from the human eye 6 is designed to include a first lens 3 and a second lens 4. Figure 1, the focal power φ1 of the first lens 3 is greater than 0, and the φ2 of the second lens 4 is less than 0. This combination of positive and negative focal powers is conducive to correcting the aberration of the near-eye optical system. In conjunction with the optical parameter constraints of the above two lenses, that is, 0<abs(φ1*n1*v2 / φ2*n2*v1)≤10, where φ1, n1, and v1 are the focal power, refractive index, and Abbe number of the first lens 3, and φ2, n2, and v2 are the focal power and refractive index Abbe number of the second lens 4, respectively. This can further reduce the chromatic aberration and distortion of the near-eye optical system, thereby improving the imaging quality in many aspects. This makes the formed near-eye optical system have good optical performance.

[0093] In some examples of the present application, the total optical power of the second optical element 200 is positive.

[0094] According to the above example, at least some of the lenses in the second optical element 200 are designed to be linearly movable along the optical axis relative to the first optical element 100, so that the diopter can be adjusted. The number of movable lenses is ≥1.

[0095] According to the above example, the total optical power of the second optical element 200 is greater than 0, which can provide a larger optical power, thereby facilitating a good zoom imaging effect, while taking into account the imaging quality of the edge field of view.

[0096] In some examples of the present application, the optical power φ of the first optical element 100 is positive.

[0097] According to the above example, the first optical element 100 has a positive focal length and is located on a side close to the human eye 6. This design is beneficial for reducing the radial size of the near-eye optical system while ensuring the optical imaging quality. The radial direction is a direction perpendicular to the optical axis.

[0098] In some examples of the present application, the first optical element 100 is a single third lens 5, and the optical power of the third lens 5 is φ, and φ is positive.

[0099] That is to say, when the first optical element 100 includes only one lens, namely the third lens 5 mentioned above, the optical focal length of the third lens 5 is the optical focal length of the first optical element 100, and therefore, the optical focal length of the third lens 5 is φ, and φ is positive.

[0100] When the first optical element 100 includes two or more optical lenses, the optical power of the first optical element 100 is the combined optical power of all the optical lenses included therein.

[0101] In some examples of the present application, the first optical element 100 and the second optical element 200 satisfy the following relationship: 0<φ / (φ+φ1+φ2)<1.

[0102] According to the above example, when the two optical elements in the near-eye optical system meet the above-mentioned constraints on optical power, a reasonable distribution of optical power can be achieved, thereby improving process feasibility.

[0103] In some examples of this application, see Figure 1 The near-eye optical system further includes a display 1, which is located on a side of the second optical element 200 away from the first optical element 100, and can emit light for imaging display.

[0104] The display 1 may be a self-luminous screen such as LCD, LED, OLED, Micro-OLED, ULED, or a reflective screen such as DMD.

[0105] In this case, for example, a screen protection element 2 may be arranged on the luminous surface of the display 1 .

[0106] The display 1 can emit RGB light, for example, to form a color image.

[0107] In some examples of this application, see Fig.19 The near-eye optical system further includes a fourth lens 10, and the fourth lens 10 is located between the first lens 3 and the display 1. The first optical element 100 is a third lens 5. The first lens 3 and the second lens 4 are located between the fourth lens 10 and the third lens 5 in sequence, and the first lens 3 and the second lens 4 are configured to be movable along the optical axis.

[0108] Based on the above example, see Fig.19 An optical lens may be added to the side of the near-eye optical system close to the display 1, and the optical lens may be fixed and immovable, for example, a fourth lens 10 is introduced. The introduction of the fourth lens 10 can improve the image quality, appropriately expand the field of view angle range and enhance the imaging resolution, and can also reduce the total length of the near-eye optical system to a certain extent.

[0109] It should be noted that, between the first optical element 100 and the display 1, including but not limited to introducing a lens, the number of optical lenses introduced can also be adjusted according to specific needs, and this is not limited in the present application.

[0110] In some examples of the present application, the display 1 is configured to emit circularly polarized light or natural light. In the case where the light emitted by the display 1 is natural light, a superimposed element is provided on the light-emitting surface of the display 1 to convert the natural light into circularly polarized light, and the superimposed element includes at least a phase retarder and a linear polarizer.

[0111] See also Figure 1 The near-eye optical system further includes a display 1. When the display 1 emits natural light, the natural light needs to be firstly polarized, so that the natural light is firstly converted into circularly polarized light and then incident on the optical elements on the left, and finally the light emitted by the first optical element 100 enters the human eye 6 for imaging.

[0112] According to the above example, the phase retarder and the linear polarizer are combined into a stacked element and mounted on the light-emitting surface of the display 1. This can reduce the difficulty of assembly and enable two optical elements to be placed simultaneously in one assembly.

[0113] The transmission axis of the linear polarizer may be in the horizontal direction, the vertical direction or any other direction.

[0114] The phase retarder is, for example, a quarter wave plate, which can realize the conversion of linear polarized light into circular polarized light and the conversion of circular polarized light into linear polarized light.

[0115] Specifically, the fast axis or slow axis direction of the phase retarder disposed on the light-emitting surface of the display 1 and the transmission axis direction of the linear polarizer form an angle of 45°.

[0116] In some examples of the present application, the beam splitter 9 is disposed on the surface of the first lens 3 close to the display 1. The phase retarder 8 and the polarized reflective element 7 are stacked and disposed on the surface of the second lens 4 away from the display 1, see Figure 2 .

[0117] According to the above example, there is no need to introduce a flat support member in the entire optical structure to support the beam splitter element 9, the phase retarder 8 and the polarization reflection element 7, so the optical architecture can be simplified.

[0118] The light splitting element 9 can be disposed on the surface of the first lens 3 close to the display 1 by, for example, attaching or plating. The light splitting element 9 can move synchronously with the movement of the first lens 3.

[0119] The polarized reflective element 7 and the phase retarder 8 are laminated and glued and then glued and arranged on the same surface of the second lens 4 (that is, the surface of the second lens 4 away from the display 1), which is conducive to the alignment adjustment between the two. Figure 2When the second mirror 4 is movable, the polarization reflection element 7 and the phase retarder 8 can move synchronously with the movement of the second mirror 4 .

[0120] The phase retarder 8 is, for example, a quarter wave plate. The polarization reflection element 7 is, for example, a polarization reflection film.

[0121] It should be noted that in the embodiments of the present application, see Figure 1 The beam splitter 9 can also be arranged on the side of the first lens 3 close to the display 1 through a support, and the phase retarder 8 and the polarized reflection element 7 can be arranged on the side of the second lens 4 close to and away from the display 1 through a support.

[0122] In some examples of this application, see Figure 2 The near-eye optical system also includes a polarizer 11, which is arranged on the side of the polarizing reflective element 7 away from the phase retarder 8, and the polarizer 11, the polarizing reflective element 7 and the phase retarder 8 are stacked to form a composite film material.

[0123] See also Figure 2 The near-eye optical system may further include a polarizer 11. The introduction of the polarizer 11 may reduce stray light, which is beneficial for improving the final imaging quality.

[0124] The polarizer 11 is, for example, a linear polarizer, and the transmission axis direction thereof can be along the horizontal direction, the vertical direction or any other direction.

[0125] The polarizer 11 may be located on a side of the polarizing reflective element 7 away from the phase retarder 8 , and the polarizer 11 , the polarizing reflective element 7 and the phase retarder 8 are stacked to form a composite film.

[0126] Of course, please continue to see Figure 2 , an anti-reflection film 12 may also be introduced into the above-mentioned composite film material.

[0127] The anti-reflection film 12 can be glued and arranged on the side of the polarization reflection element 7 away from the phase retarder 8, for example.

[0128] In some examples of the present application, the absolute value of distortion of the near-eye optical system is less than 4%, and the maximum chromatic aberration value is less than 20 μm.

[0129] According to the near-eye optical system provided in the embodiment of the present application, at least three optical lenses are used, namely Figure 1The first lens 3, the second lens 4, and the third lens 5 are shown in FIG. Of course, a fourth lens 10 may be additionally introduced into the near-screen side of the near-eye optical system, as shown in FIG. Fig.19 .

[0130] It should be noted that the near-eye optical system of the embodiment of the present application uses at least three lenses, namely, a first lens 3, a second lens 4 and a third lens 5. The three lenses are described below.

[0131] The near-eye optical system uses three lenses, and the refractive index and dispersion coefficient of the materials used in the three lenses are in the range of: 1.4 <n<2.0,20<v<75。

[0132] The refractive index and dispersion coefficient of the first lens 3 are: n1=1.54, v1=56.3. The refractive index and dispersion coefficient of the second lens 4 are: n2=1.76, v2=27.6. The refractive index and dispersion coefficient of the third lens 5 are: n3=1.54, v3=55.7.

[0133] The center thickness T1 of the first lens 3 is in the range of 1mm≤T1≤8mm, and it includes two optical surfaces, namely a first surface and a second surface. The two surfaces may be aspherical surfaces. The first surface is close to the display 1 , and the second surface is far from the display 1 .

[0134] The light splitting element 9 may be arranged on the first surface of the first lens 3 .

[0135] An anti-reflection film material may be selectively disposed on the second surface of the first lens 3 .

[0136] The central thickness T2 of the second lens 4 is in the range of 1 mm ≤ T2 ≤ 10 mm, and the second lens 4 includes two optical surfaces, namely a third surface and a fourth surface, which can be aspherical surfaces or plane surfaces. The third surface is close to the display 1 , and the fourth surface is far from the display 1 .

[0137] Among them, see Figure 2 A composite film material may be disposed on the fourth surface of the second lens 4, and the composite film material may include an anti-reflection film 12, a phase retarder 8, a polarized reflection element 7 (transmitting P light and reflecting S light) and a polarizer 11 (transmitting P light).

[0138] An anti-reflection film material may also be selectively disposed on the third surface.

[0139] The central thickness T3 of the third lens 5 is in the range of 1 mm ≤ T3 ≤ 8 mm, and the third lens 5 includes two optical surfaces, namely a fifth surface and a sixth surface, which may be aspherical surfaces. The fifth surface is close to the display 1 , and the sixth surface is far from the display 1 .

[0140] The fifth surface and the sixth surface may be selectively provided with anti-reflection film material.

[0141] See also Figure 1 , the light propagation process of the near-eye optical system is as follows:

[0142] The display 1 emits circularly polarized light, which is transmitted through the first lens 3, converted into linearly polarized light (S light) through the phase retarder 8 (quarter wave plate) on the fourth surface of the second lens 4, reflected through the polarization reflection element 7, converted into circularly polarized light through the phase retarder 8, reflected through the beam splitting element 9 on the first surface of the first lens 3, converted into linearly polarized light (P light) through the phase retarder 8 again, transmitted through the third lens 5, and hits the human eye 6.

[0143] The optical performance of the near-eye optical system provided by the embodiments of the present application is described below through Examples 1 to 3.

[0144] The optical performance of the near-eye optical system provided by the embodiments of the present application is described below through Examples 1 to 3.

[0145] Example 1

[0146] The optical structure of the near-eye optical system provided in this embodiment 1 can be seen in Figure 1 , which comprises a first optical element 100, a second optical element 200 and a display 1 which are sequentially arranged along the same optical axis;

[0147] The first optical element 100 comprises only one third lens 5;

[0148] The second optical element 200 is composed of a first lens 3 and a second lens 4, and the first lens 3 is capable of moving along the optical axis;

[0149] The beam splitter 9 is disposed on the surface of the first lens 3 close to the display 1 (first surface); the phase retarder 8, the polarizing reflective element 7 and the polarizer 11 are stacked and disposed on the surface of the second lens 4 away from the display 1 (fourth surface).

[0150] Table 1 shows the specific optical parameters of the near-eye optical system of this embodiment 1.

[0151]

[0152] The optical performance of the near-eye optical system provided in this embodiment 1 is demonstrated below through a dot array diagram, an MTF curve diagram, field curvature and distortion, and vertical axis chromatic aberration.

[0153] A point diagram refers to a diffuse pattern formed in a certain range when many light rays emitted from one point pass through the optical system and their intersection with the image plane is no longer concentrated at the same point due to aberration. It is mainly used to evaluate the imaging quality of the projection optical system.

[0154] The MTF curve is a modulation transfer function graph that characterizes the imaging clarity of an optical system through the contrast of black and white line pairs.

[0155] Vertical axis chromatic aberration is also called magnification chromatic aberration, which mainly refers to a complex main light ray on the object side, which becomes multiple light rays when it emerges on the image side due to the dispersion of the refraction system, and the difference in the focal position of blue light and red light on the image plane.

[0156] Figures 3 to 6 The diagram shows an extreme case in which the first lens 3 moves to change the diopter in the near-eye display system provided in the first embodiment.

[0157] See also Figure 3 , the maximum value of the image point in the point diagram is less than 7μm.

[0158] See also Figure 4 , MTF>0.7 at 24lp / mm.

[0159] See also Figure 5 , the maximum distortion occurs in 1 field of view, and the absolute value is less than 4%.

[0160] See also Figure 6 , the maximum color difference value is less than 20μm.

[0161] Figures 8 to 11 Another limit of the change in the diopter of the first lens 3 in the near-eye display system provided by the present embodiment 1 is shown.

[0162] See also Figure 8 , the maximum value of the image point in the point diagram is less than 22μm.

[0163] See also Fig. 9 , MTF>0.3 at 24lp / mm.

[0164] See also Fig.10 , the maximum distortion occurs in 1 field of view, and the absolute value is less than 4%.

[0165] See also Fig.11 , the maximum color difference value is less than 20μm.

[0166] Example 2

[0167] The near-eye optical system shown in this embodiment 2 has an optical architecture that is the same as that of the above-mentioned embodiment 1, except that the optical parameters are different, as shown in Table 2 below, and the first lens 3 and the second lens 4 in the first optical element 100 are designed to move simultaneously.

[0168] Table 2 shows the specific optical parameters of the near-eye optical system, which are as follows.

[0169] Table 2

[0170]

[0171] The optical performance of the near-eye optical system provided by this embodiment 2 is demonstrated below through a dot array diagram, an MTF curve diagram, field curvature and distortion, and vertical axis chromatic aberration.

[0172] Figures 11 to 14 It shows an extreme case in which the first lens 3 and the second lens 4 move simultaneously to change the diopter in the near-eye display system provided by the present embodiment 2.

[0173] See also Fig.11 , the maximum value of the image point in the point diagram is less than 35μm.

[0174] See also Fig.12 , MTF>0.4 at 24lp / mm.

[0175] See also Fig.13 , the maximum distortion occurs in 1 field of view, and the absolute value is less than 4%.

[0176] See also Fig.14 , the maximum color difference value is less than 20μm.

[0177] Figures 15 to 18 Another extreme case in which the first lens 3 and the second lens 4 move simultaneously to change the diopter in the near-eye display system provided by Embodiment 2 is shown.

[0178] See also Fig.15 , the maximum value of the image point in the point diagram is less than 10μm.

[0179] See also Fig.16 , MTF>0.6 at 24lp / mm.

[0180] See also Fig.17 , the maximum distortion occurs in 1 field of view, and the absolute value is less than 4%.

[0181] See also Fig.18 , the maximum color difference value is less than 20μm.

[0182] Example 3

[0183] The near-eye optical system shown in the present embodiment 3 is different from the near-eye optical system shown in the aforementioned embodiment 1 in that: a fixed fourth lens 10 is added between the first lens 3 and the display 1, and the first lens 3 and the second lens 4 are controlled to move synchronously along the optical axis. The optical architecture shown in the present embodiment 3 is shown in FIG. Fig.19 .

[0184] Table 3 shows the specific optical parameters of the near-eye optical system, which are as follows.

[0185] Table 3

[0186]

[0187]

[0188] The optical performance of the near-eye optical system provided by this embodiment 3 is demonstrated below through a dot array diagram, an MTF curve diagram, field curvature and distortion, and vertical axis chromatic aberration.

[0189] Figure 20 to Figure 23 It shows an extreme case in which the first lens 3 and the second lens 4 move simultaneously to change the diopter in the near-eye display system provided by the present embodiment 3.

[0190] See also Fig. 20 The maximum value of the image point in the point diagram is less than 13μm.

[0191] See also Fig.21 , MTF>0.6 at 24lp / mm.

[0192] See also Fig. 22 , the maximum distortion occurs in 1 field of view, and the absolute value is less than 4%.

[0193] See also Fig.23 , the maximum color difference value is less than 20μm.

[0194] Figure 24 to Figure 27 Another extreme case in which the first lens 3 and the second lens 4 move simultaneously to change the diopter in the near-eye display system provided by the present embodiment 3 is shown.

[0195] See also Fig.24 The maximum value of the pixel in the point diagram is less than 29μm.

[0196] See also Fig.25 , MTF>0.4 at 24lp / mm.

[0197] See also Fig.26 , the maximum distortion occurs in 1 field of view, and the absolute value is less than 3%.

[0198] See also Fig. 27 , the maximum color difference value is less than 24μm.

[0199] According to the above-mentioned embodiments 1 to 3, the near-eye optical system provided by the present application has optical properties of low chromatic aberration and low distortion, and can ensure good optical properties by achieving zooming as the second optical element 200 moves.

[0200] According to another embodiment of the present application, a head-mounted display device is provided.

[0201] The head mounted display device comprises a housing and the near-eye optical system as described above.

[0202] The head mounted display device includes VR smart glasses or VR smart helmets, etc., which is not limited in the embodiments of the present application.

[0203] The specific implementation of the head-mounted display device of the embodiment of the present application can refer to the above-mentioned embodiments of the near-eye optical system, so it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0204] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0205] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A near-eye optical system, characterized in that: It comprises a first optical element (100), a polarization reflection element (7), a phase retarder (8), a second optical element (200) and a beam splitting element (9) arranged along the same optical axis; The first optical element (100) comprises at least one lens; The second optical element (200) comprises a first lens (3) and a second lens (4), and at least one lens in the second optical element (200) is movable along the optical axis; The second optical element (200) satisfies the following: 0<abs(φ1*n1*v2 / φ2*n2*v1)≤10, wherein φ1, n1, v1 are respectively the optical focal length, refractive index and Abbe number of the first lens (3), and φ2, n2, v2 are respectively the optical focal length and refractive index Abbe number of the second lens (4).

2. The near-eye optical system according to claim 1, characterized in that: The optical power φ1 of the first lens (3) is positive, and the optical power φ2 of the second lens (4) is negative.

3. The near-eye optical system according to claim 1, characterized in that: The total optical power of the second optical element (200) is positive.

4. The near-eye optical system according to claim 1, characterized in that: The optical power φ of the first optical element (100) is positive.

5. The near-eye optical system according to claim 1, characterized in that: The first optical element is a single third lens (5), the optical power of the third lens (5) is φ, and φ is positive.

6. The near-eye optical system according to claim 4 or 5, characterized in that: The first optical element (100) and the second optical element (200) satisfy the following relationship: 0<φ / (φ+φ1+φ2)<1.

7. The near-eye optical system according to claim 6, characterized in that: The near-eye optical system further comprises a display (1), wherein the display (1) is located on a side of the second optical element (200) facing away from the first optical element (100), and the display (1) is capable of emitting light for imaging display.

8. The near-eye optical system according to claim 7, characterized in that: The near-eye optical system further comprises a fourth lens (10), and the fourth lens (10) is located between the first lens (3) and the display (1); The first optical element (100) is a third lens (5); The first lens (3) and the second lens (4) are located between the fourth lens (10) and the third lens (5) in sequence, and the first lens (3) and the second lens (4) are configured to be movable along the optical axis.

9. The near-eye optical system according to claim 7, characterized in that: The display (1) is configured to emit circularly polarized light or natural light; When the light emitted by the display (1) is natural light, the light-emitting surface of the display (1) is provided with a superimposed element for converting the natural light into circularly polarized light, and the superimposed element comprises at least a phase delay plate and a linear polarizer.

10. The near-eye optical system according to any one of claims 7 to 9, characterized in that: The light splitting element (9) is arranged on a surface of the first lens (3) close to the display (1); The phase retarder (8) and the polarized reflective element (7) are stacked and arranged on a surface of the second lens (4) away from the display (1).

11. The near-eye optical system according to claim 10, characterized in that: The near-eye optical system further comprises a polarizer (11), wherein the polarizer (11) is arranged on a side of the polarizing reflective element (7) away from the phase retarder (8), and the polarizer (11), the polarizing reflective element (7) and the phase retarder (8) are stacked to form a composite film material.

12. The near-eye optical system according to claim 1, wherein: The absolute value of distortion of the near-eye optical system is less than 4%, and the maximum chromatic aberration value is less than 20 μm.

13. A head mounted display device, characterized in that: include: shell; as well as, A near-eye optical system as claimed in any one of claims 1 to 12.

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