Near-eye optical systems and head-mounted display devices

Abstract

Embodiments of the present application provide a near-eye optical system and a head-mounted display device. The near-eye optical system includes a polarizing reflective element, a phase retarder, and a beam splitter arranged along the same optical axis, with the phase retarder located between the beam splitter and the polarizing reflective element. The near-eye optical system also includes a first optical element located between the beam splitter and the phase retarder, the first optical element being a lens assembly, and the optical power of the first optical element being φ1. The near-eye optical system satisfies the following conditions: 0.5 ≤ sin(arctan(D / (2*T1)))*φ1*D ≤ 1.5. The center spacing between the beam splitter and the polarizing reflective element is T1, and the maximum optical aperture of the near-eye optical system is D. The near-eye optical system provided by embodiments of the present application can reduce the size of the near-eye optical system while ensuring a large field of view.

Description

Technical Field

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

[0002] The core component of virtual reality (VR) technology is the optical system used within it. The quality of its displayed images directly determines the quality of the VR device. To enhance the user's immersive experience, higher requirements are placed on the field of view (FOV) of the optical system in VR devices, requiring it to be as large as possible. However, given a certain eye distance, a larger FOV requires a larger optical system, creating a difficult trade-off between a large FOV and a large optical system. 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 includes a polarizing reflective element, a phase retarder, and a beam splitter arranged along the same optical axis, wherein the phase retarder is located between the beam splitter and the polarizing reflective element;

[0005] The near-eye optical system further includes a first optical element, the first optical element is located between the beam splitter and the phase retarder, the first optical element is a lens group, and the optical power of the first optical element is φ1;

[0006] The near-eye optical system satisfies the following: 0.5≤sin(arctan(D / (2*T1)))*φ1*D≤1.5; wherein, the center interval between the beam splitting element and the polarized reflection element is T1, and the maximum optical aperture of the near-eye optical system is D.

[0007] Optionally, the near-eye optical system satisfies: 0.98≤sin(arctan(D / (2*T1)))*φ1*D≤1.4.

[0008] Optionally, the first optical element includes N lenses, and N≥2.

[0009] Optionally, the first optical element includes a first lens and a second lens;

[0010] The beam splitter is disposed on a surface of the second lens away from the first lens. The phase retarder and the polarization reflective element are stacked and disposed on a surface of the first lens away from the second lens.

[0011] Optionally, a curvature radius of a surface of the first lens away from the second lens is R, and R<0.

[0012] Optionally, the total optical power of the near-eye optical system is φ, and the near-eye optical system further satisfies: abs(1 / (R*φ))≤2.

[0013] Optionally, the edge interval between the light splitting element and the polarized reflective element is T2, and T2 and T1 satisfy: 0<(T2-T1) / (T2+T1)≤1.

[0014] Optionally, the near-eye optical system further includes a display screen, which emits light for imaging display, and the display screen is located on a side of the beam splitting element away from the first optical element.

[0015] Optionally, the near-eye optical system further includes a second optical element, the second optical element is located between the display screen and the beam splitting element, the second optical element includes at least one lens, and the optical power of the second optical element is positive.

[0016] Optionally, the second optical element is a third lens, and the optical power of the third lens is positive.

[0017] Optionally, the optical power of the first optical element is positive, and 0.005≤φ1≤0.1.

[0018] Optionally, a polarizer is provided on a side of the polarized reflective element away from the phase retarder; the phase retarder, the polarized reflective element and the polarizer are stacked to form a composite film.

[0019] Optionally, the display screen is configured to emit circularly polarized light or natural light;

[0020] In the case that the light emitted by the display screen is natural light, the light-emitting surface of the display screen is further 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.

[0021] In a second aspect, the present application provides a head-mounted display device. The head-mounted display device includes:

[0022] a housing; and

[0023] The near-eye optical system as described in the first aspect.

[0024] The beneficial effects of this application are:

[0025] According to the near-eye optical system provided in the embodiment of the present application, in the optical architecture of the folded light path, by reasonably constraining the relationship between the center interval T1 between the splitting element and the polarization reflection element, the optical focal length φ1 of the lens group between the two optical elements, and the maximum optical aperture D of the near-eye optical system, the size of the near-eye optical system can be reduced while ensuring a large field of view, especially the radial size of the near-eye optical system can be reduced, while the near-eye optical system can also take into account high-definition imaging.

[0026] 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

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0028] Figure 1 This is one of the structural schematic diagrams of the near-eye optical system provided in an embodiment of the present application;

[0029] Figure 2 This is a second structural diagram of the near-eye optical system provided in an embodiment of the present application;

[0030] Figure 3 A schematic diagram of the arrangement of the composite membrane material provided in an embodiment of the present application;

[0031] Figure 4 A dot array diagram of the near-eye optical system provided in Example 1 of the present application;

[0032] Figure 5 A modulation transfer function (MTF) curve diagram of the near-eye optical system provided in Example 1 of the present application;

[0033] Figure 6 Field curvature and distortion diagram of the near-eye optical system provided in Example 1 of the present application;

[0034] Figure 7 A vertical axis chromatic aberration diagram of the near-eye optical system provided in Example 1 of the present application;

[0035] Figure 8 The third structural diagram of the near-eye optical system provided in an embodiment of the present application;

[0036] Figure 9 A dot array diagram of the near-eye optical system provided in Example 2 of the present application;

[0037] Figure 10 A modulation transfer function (MTF) curve diagram of the near-eye optical system provided in Example 2 of the present application;

[0038] Figure 11 Field curvature and distortion diagram of the near-eye optical system provided in Example 2 of the present application;

[0039] Figure 12 A vertical axis chromatic aberration diagram of the near-eye optical system provided in Example 2 of the present application;

[0040] Figure 13 This is a fourth structural diagram of the near-eye optical system provided in an embodiment of the present application;

[0041] Figure 14 A dot array diagram of the near-eye optical system provided in Example 3 of the present application;

[0042] Figure 15 A modulation transfer function (MTF) curve diagram of the near-eye optical system provided in Example 3 of the present application;

[0043] Figure 16 Field curvature and distortion diagram of the near-eye optical system provided in Example 3 of the present application;

[0044] Figure 17 This is a diagram of vertical axis chromatic aberration of the near-eye optical system provided in Example 3 of the present application.

[0045] Description of reference numerals:

[0046] 1. Display screen; 2. Screen protection glass; 3. Third lens; 31. Fifth surface; 32. Sixth surface; 4. Second lens; 41. Third surface; 42. Fourth surface; 5. First lens; 51. First surface; 52. Second surface; 6. Beam splitter; 7. Phase retarder; 8. Polarized reflective element; 9. Polarizer; 01. Human eye. DETAILED DESCRIPTION

[0047] 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 arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0048] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0049] 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.

[0050] 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.

[0051] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0052] The near-eye optical system and head-mounted display device provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0053] According to one aspect of an embodiment of the present application, a near-eye optical system is provided, which is suitable for use in 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 may include, for example, VR smart glasses or a VR smart helmet. In the embodiments of the present application, there is no specific limitation on the form of the head-mounted display device.

[0054] The near-eye optical system proposed in the embodiment of this application is shown in FIG. Figure 1 and Figure 2 The near-eye optical system includes a polarizing reflective element 8, a phase retarder 7, and a beam splitter 6 arranged along the same optical axis, and the phase retarder 7 is located between the beam splitter 6 and the polarizing reflective element 8. The near-eye optical system also includes a first optical element, which is located between the beam splitter 6 and the phase retarder 7. The first optical element is a lens group, and the optical power of the first optical element is φ1. The near-eye optical system satisfies the following conditions: 0.5≤sin(arctan(D / (2*T1)))*φ1*D≤1.5; wherein the center distance between the beam splitter 6 and the polarizing reflective element 8 is T1, and the maximum optical aperture of the near-eye optical system is D.

[0055] According to the above-described embodiment of the present application, the near-eye optical system includes a beam splitter 6, a first optical element, a phase retarder 7, and a polarizing reflector 8, which are sequentially arranged along the same optical axis. These elements, in conjunction with the first optical element, can form a folded optical path. The first optical element is a lens assembly located between the beam splitter 6 and the phase retarder 7, which can cause incident light to be folded back between the beam splitter 6 and the polarizing reflector 8, ultimately exiting to form an image in the human eye 01. The use of a folded optical path can make the entire near-eye optical system more compact while ensuring image quality.

[0056] Furthermore, the optical parameter design of the near-eye optical system provided in the embodiment of the present application satisfies the optical parameter constraint condition of 0.5≤sin(arctan(D / (2*T1)))*φ1*D≤1.5, wherein D is the maximum optical aperture of the near-eye optical system, T1 is the center distance between the beam splitting element 6 and the polarized reflective element 8, see Figure 2 , φ1 is the optical power of the first optical element, which is designed to be greater than 0. By rationally constraining the aforementioned optical parameters of the near-eye optical system, the radial dimensions of the near-eye optical system can be effectively reduced while maintaining a large field of view (FOV), enabling high-definition imaging. In other words, the resulting near-eye optical system meets the development trend of large FOV, high-definition, and compact VR devices.

[0057] The D value above is the maximum optical diameter of all lenses in a near-eye optical system, which can be expressed as the optical half-diameter * 2. The optical half-diameter of a lens refers to the radial dimension from the center of the lens to the edge of the optically effective area on the lens.

[0058] The near-eye optical system provided in the embodiment of the present application has a field of view (FOV) of up to 100° or even higher, which can provide users with a better immersive experience.

[0059] Compared to traditional folded optical path solutions, the near-eye optical system provided by the embodiments of the present application can be reduced in radial size by approximately 20%. This means that the radial volume of the near-eye optical system can be compressed, unlike traditional methods that only reduce the volume along the optical axis. By compressing the radial size, the near-eye optical system provided by the embodiments of the present application has a small radial size when assembled on a VR device, freeing up space for the interpupillary distance adjustment device for the left and right eyes.

[0060] It should be noted that the optical power is the reciprocal of the focal length of the lens. For example, the optical power φ1 of the first optical element is the reciprocal of the focal length of the first optical element.

[0061] See also Figure 1 and Figure 2 In the near-eye optical system, the first optical element is, for example, close to the human eye 01. At this time, the first optical element includes an optical lens with a maximum radial size, which can converge light into the human eye 01 to the greatest extent.

[0062] The near-eye optical system provided by the embodiment of the present application can not only reduce the size of the system under a large field of view, but also achieve high-definition imaging. Figure 5 、 Figure 10 and Figure 15 The MTF of the near-eye optical system is greater than 0.2 at 19lp / mm, indicating that the imaging clarity of the near-eye optical system is better.

[0063] According to the near-eye optical system provided by the embodiment of the present application, in the optical architecture of the folded optical path, see Figure 2By reasonably constraining the relationship among the center interval T1 between the beam splitter element 6 and the polarizing reflective element 8, the optical power φ1 of the lens group between the two optical elements, and the maximum aperture D of the near-eye optical system, it is possible to reduce the size of the near-eye optical system while ensuring a large field of view (e.g., FOV ≥ 100°), especially the radial size of the near-eye optical system (the radial size can be reduced by 20%), while also enabling the near-eye optical system to achieve high-definition imaging.

[0064] In the near-eye optical system provided in the embodiment of the present application, the beam splitter element 6 is configured to allow a portion of light to be transmitted and another portion of light to be reflected.

[0065] For example, the light splitting element 6 is a semi-transmissive and semi-reflective film.

[0066] It should be noted that the reflectivity and transmittance of the light-splitting element 6 can be flexibly adjusted according to specific needs, and this is not limited in the embodiments of the present application.

[0067] In the near-eye optical system provided in the embodiment of the present application, the phase retarder 7 can be used to change the polarization state of light. Specifically, it can be used to convert linearly polarized light into circularly polarized light, or convert circularly polarized light into linearly polarized light.

[0068] For example, the phase retarder 7 is a quarter-wave plate.

[0069] Of course, the phase retarder 7 can be set as other phase retarder plates as needed, such as a half-wave plate.

[0070] In the near-eye optical system provided in the embodiment of the present application, the polarized reflective element 8 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.

[0071] In the embodiment of the present application, the phase retarder 7 and the polarized reflective element 8 cooperate with each other to analyze and transmit light.

[0072] In some examples of the present application, the near-eye optical system satisfies: 0.98≤sin(arctan(D / (2*T1)))*φ1*D≤1.4.

[0073] The maximum optical aperture D of the near-eye optical system is, for example, 28 mm ≤ D ≤ 34 mm.

[0074] The optical power φ1 of the first optical element is, for example, 0.005≤φ1≤0.1.

[0075] In some examples of the present application, the first optical element includes N lenses, and N≥2.

[0076] Based on the above example, see Figure 1 and Figure 2 At least two lenses are arranged between the beam splitter 6 and the phase retarder 7. This design can reduce the axial size of the near-eye optical system to achieve a lightweight design of the near-eye optical system while ensuring image quality.

[0077] That is to say, the near-eye optical system provided in the embodiment of the present application has compressed dimensions in both the optical axis direction and the radial direction, which can further reduce the volume and weight of the near-eye optical system while ensuring a large field of view and high-definition imaging.

[0078] It should be noted that more than two lenses may be introduced between the beam splitter 6 and the phase retarder 7. While appropriately increasing the number of lenses can further reduce the overall length (dimension along the optical axis) of the near-eye optical system, this may increase the system's weight and production cost. In practical applications, the number of lenses between the beam splitter 6 and the polarizing reflector 8 can be adjusted based on specific needs, but at least two lenses are required between the two elements.

[0079] In some examples of this application, see Figure 1 and Figure 2 The first optical element includes a first lens 5 and a second lens 4. The beam splitter 6 is arranged on the surface of the second lens 4 away from the first lens 5, and the phase retarder 7 and the polarization reflection element 8 are stacked and arranged on the surface of the first lens 5 away from the second lens 4. Figure 3 .

[0080] According to the above example, the first optical element includes two lenses, for example, Figure 1 and Figure 2 The two lenses are a first lens 5 and a second lens 4. The first lens 5 is closer to the human eye 01 than the second lens 4. The phase retarder 7 and the polarizing reflective element 8 can be bonded to the surface of the first lens 5 closer to the human eye 01, while the beam splitter 6 can be separately provided on the surface of the second lens 4 farther from the human eye 01. The beam splitter 6 can be provided on the surface of the second lens 4 farther from the human eye 01, for example, by attachment or plating.

[0081] For example, see Figure 1The first lens 5 includes a first surface 51 and a second surface 52, the first surface 51 is away from the human eye 01, and the second surface 52 is close to the human eye 01, and the phase retarder 7 and the polarization reflection element 8 are stacked in sequence on the second surface 52.

[0082] For example, see Figure 1 The second lens 4 includes a third surface 41 and a fourth surface 42 , the third surface 41 is away from the human eye 01 , the fourth surface 42 is close to the human eye 01 , and a spectroscopic element 6 is provided on the third surface 41 .

[0083] According to the above example, the second lens 4 is used to support the spectrometer element 6, and the first lens 5 is used to support the phase delay device 7 and the polarization reflection element 8, so that there is no need to introduce additional support members in the optical path to support these elements that form the folded optical path.

[0084] According to the above example, the sum of the thickness of the first lens 5 , the thickness of the second lens 4 and the air space between them is the interval T1 between the light splitting element 6 and the polarized reflection element 8 .

[0085] Based on the above example, see Figure 1 The first optical element can, for example, be composed of a first lens 5 and a second lens 4. Since the first optical element is located close to the human eye 01, the optical apertures of the first lens 5 and the second lens 4 can be designed to be relatively large. For example, the optical apertures of the first lens 5 and the second lens 4 can be the same, with both being the lenses with the largest optical aperture in the near-eye optical system. Of course, one of the first lens 5 and the second lens 4 can also be the lens with the largest optical aperture in the near-eye optical system, and this is not a limitation in this application.

[0086] In some examples of the present application, the curvature radius of the surface of the first lens 5 away from the second lens 4 is R, and R<0.

[0087] See also Figure 1 The curvature radius R of the second surface 52 of the first lens 5 close to the human eye 01 is negative. This design can reduce the aperture of the lens.

[0088] It should be noted that the first lens 5 is, for example, the first lens close to the human eye 01, and its aperture is usually relatively large. By reducing its aperture, the aperture sizes of other lenses in the optical path can be reduced accordingly, thereby helping to reduce the radial size and weight of the entire near-eye optical system.

[0089] In some examples of the present application, the total optical power of the near-eye optical system is φ, and the near-eye optical system also satisfies: abs(1 / (R*φ))≤2.

[0090] According to the range of the constraint relationship between the total optical power φ of the near-eye optical system and the curvature radius R of the second surface 52 of the first lens 5 close to the human eye 01 in the above example, the radial size of the near-eye optical system can be further reduced.

[0091] Wherein, the range of the total optical power φ of the near-eye optical system is: 0.1≤φ≤1.

[0092] In some examples of this application, see Figure 2 The edge interval between the light splitting element 6 and the polarized reflective element 8 is T2, and the relationship between T2 and T1 satisfies: 0<(T2-T1) / (T2+T1)≤1.

[0093] Wherein, T1 is the center distance between the light splitting element 6 and the polarized reflection element 8 .

[0094] By constraining the size of the center interval and the edge interval between the light splitting element 6 and the polarized reflective element 8, the field curvature and distortion of the imaging can be improved under a large field of view (such as FOV≥100°), especially the imaging quality of the edge field of view can be taken into account.

[0095] In some examples of this application, see Figure 1 The near-eye optical system further includes a display screen 1 , which emits light for imaging display. The display screen 1 is located on a side of the beam splitting element 6 away from the first optical element.

[0096] See also Figure 1 A protective glass 2 may be provided on the light emitting surface of the display screen 1 to protect the display screen 1 .

[0097] The display screen 1 can be, for example, a self-luminous screen such as LCD, LED, OLED, Micro-OLED, ULED, or a reflective screen such as DMD.

[0098] The display screen 1 can emit RGB light, for example, to form a color image.

[0099] In some examples of this application, see Figure 1 The near-eye optical system further includes a second optical element, which is located between the display screen 1 and the beam splitter 6. The second optical element includes at least one lens, and the optical power of the second optical element is positive.

[0100] According to the above example, in the near-eye optical system, at least one lens (the number of lenses ≥ 1) can be set between the display screen 1 and the beam splitter 6. Adding a certain number of lenses to this position can improve image quality.

[0101] The optical power of the second optical element is φ2, -0.05≤φ2≤0.05.

[0102] Preferably, the second optical element is designed to have a positive optical power, i.e., 0 ≤ φ2 ≤ 0.05. This design effectively reduces the incident angle of light on the beam splitter 6, easing the coating process and, consequently, the manufacturing process. Furthermore, the positive optical power provided by the second optical element also ensures image quality in the peripheral field of view.

[0103] Optionally, see Figure 1 The second optical element is the third lens 3, and the optical power of the third lens 3 is positive.

[0104] That is, when the second optical element is a single lens, the optical power of the second optical element is the optical power of the single lens. For example, the second optical element is the third lens 3, and the optical power range of the third lens 3 is the range of φ2.

[0105] The preferred range of the third lens 3 is 0 to 0.05 (including both endpoints).

[0106] When the second optical element is composed of two or more lenses, the optical power of the second optical element is the combined optical power of all the lenses, and the specific range of φ2 can be referred to above.

[0107] In some examples of the present application, the optical power φ1 of the first optical element is positive, and 0.005≤φ1≤0.1.

[0108] See also Figure 1 The first optical element includes at least two lenses, for example, a first lens 5 and a second lens 4, and the combined optical power of the first lens 5 and the second lens 4 is positive.

[0109] It should be noted that in the near-eye optical system, the optical focal length of the first optical element located on the side of the human eye 01 is positive, and the optical focal length of the second optical element located on the side of the display screen 1 is also positive. This design can achieve a large field of view angle (for example, 100°) with a small screen size, for example, the screen size is 0.9-1.4 inches, which is conducive to reducing the volume and weight of the entire near-eye optical system.

[0110] In some examples of this application, see Figure 3 A polarizer 9 is provided on the side of the polarized reflective element 8 away from the phase retarder 7; the phase retarder 7, the polarized reflective element 8 and the polarizer 9 are stacked to form a composite film material.

[0111] See also Figure 3 The near-eye optical system may further include a polarizer 9. The introduction of the polarizer 9 can reduce stray light, which is beneficial for improving the final imaging quality.

[0112] The polarizer 9 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.

[0113] Of course, an anti-reflection film may also be introduced into the above-mentioned composite film material.

[0114] In some examples of the present application, the display screen 1 is configured to emit circularly polarized light or natural light; when the light emitted by the display screen 1 is natural light, the light-emitting surface of the display screen 1 is also provided with a superimposed element for converting the natural light into circularly polarized light, and the superimposed element includes at least a phase delay plate and a linear polarizer.

[0115] When the display screen 1 emits natural light, the polarization state of the natural light needs to be converted first, so that the natural light is first converted into circularly polarized light and then enters the optical elements on the left. Finally, the light emitted by the first optical element enters the human eye 01 for imaging.

[0116] 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 screen 1 . This can reduce the difficulty of assembly and enable two optical elements to be placed simultaneously in one assembly.

[0117] The transmission axis of the linear polarizer may be in the horizontal direction, the vertical direction or any other direction.

[0118] The phase retarder is, for example, a quarter-wave plate, which can convert linearly polarized light into circularly polarized light, or vice versa.

[0119] According to the near-eye optical system provided in the embodiments of the present application, the first optical element includes, but is not limited to, two lenses, and a larger number of lenses, such as three lenses, can be used as needed. The second optical element includes, but is not limited to, a single lens, and a larger number of lenses, such as two lenses, can be used as needed. Furthermore, it should be noted that the introduction of the second optical element is a preferred solution and can improve imaging quality.

[0120] According to the near-eye optical system provided in the embodiment of the present application, see Figure 1 , the light propagation is as follows:

[0121] Display screen 1 emits circularly polarized light, which is transmitted through third lens 3 and second lens 4. It then passes through phase retarder 7 on second surface 52 of first lens 5 and becomes linearly polarized light (S light). The light is then reflected by polarizing reflective element 8 and again passes through phase retarder 7 to become circularly polarized light. The light is then reflected by beam splitter 6 on third surface 41 of second lens 4 and again passes through phase retarder 7 to become linearly polarized light (P light). The light is then transmitted through first lens 5 and enters human eye 01.

[0122] The near-eye optical system of the embodiment of the present application, see Figure 1 , which includes a first lens 5, a second lens 4 and a third lens 3. The refractive index and dispersion coefficient of the materials used in the first lens 5, the second lens 4 and the third lens 3 are in the range of: 1.4 <n<2.0,20<v<75。

[0123] For example, the first lens 5 , the second lens 4 and the third lens 3 have the same refractive index and dispersion coefficient, which are all designed to be: n=1.54, v=56.3.

[0124] The center thickness T1 of the first lens 5 is in the range of 1mm≤T1≤10mm, and it includes two optical surfaces, namely a first surface 51 and a second surface 52. The two surfaces can be aspherical or flat. The first surface 51 is close to the display screen 1, and the second surface 52 is far away from the display screen 1.

[0125] Wherein, an anti-reflection film may be selectively provided on the first surface 51 of the first lens 5 .

[0126] The composite film material described above can be mounted on the second surface 52 of the first lens 5, including the stacked phase retarder 7, the polarized reflective element 8 (transmitting P light and reflecting S light), and the polarizer 9. Of course, an anti-reflective film can also be introduced into the composite film material.

[0127] The second lens 4 has a center thickness T2 in the range of 1 mm ≤ T2 ≤ 8 mm and includes two optical surfaces, namely a third surface 41 and a fourth surface 42 , which can be aspherical or flat. The third surface 41 is close to the display screen 1 , while the fourth surface 42 is far away from the display screen 1 .

[0128] The light splitting element 6 may be provided on the third surface 41 of the second lens 4 by coating or laminating.

[0129] Wherein, an anti-reflection film may be selectively provided on the fourth surface 42 of the second lens 4 .

[0130] The third lens 3 has a center thickness T3 in the range of 1 mm ≤ T3 ≤ 8 mm and includes two optical surfaces, namely a fifth surface 31 and a sixth surface 32 . These two surfaces can be aspherical or planar. The fifth surface 31 is close to the display screen 1 , while the sixth surface 32 is far from the display screen 1 .

[0131] The fifth surface 31 and the sixth surface 32 may be selectively provided with an anti-reflection film.

[0132] 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.

[0133] Example 1

[0134] The near-eye optical system provided in this embodiment 1 is shown in FIG. Figure 1 and Figure 2 , which includes a polarizer 9, a polarization reflection element 8, a phase retarder 7, a first lens 5, a second lens 4, a beam splitter 6, a third lens 3 and a display screen 1, which are sequentially arranged along the same optical axis;

[0135] The polarizer 9, the polarizing reflective element 8, and the phase retarder 7 are laminated and glued to form a composite film, and the composite film is disposed on the second surface 52 of the first lens 5;

[0136] The light splitting element 6 is disposed on the third surface 41 of the second lens 4;

[0137] The optical power φ1 of the first optical element is 0.012;

[0138] The optical power φ2 of the second optical element is: -0.05≤φ2≤0.05;

[0139] The maximum optical aperture D of the near-eye optical system is 34 mm;

[0140] The near-eye optical system satisfies: sin(arctan(D / (2*T1)))*φ1*D=1.4.

[0141] Table 1 shows the specific optical parameters of the near-eye optical system of this embodiment 1.

[0142] Table 1

[0143]

[0144] The optical performance of the near-eye optical system provided in Example 1 is demonstrated below through a dot array diagram, an MTF curve diagram, field curvature and distortion, and vertical axis chromatic aberration.

[0145] A point diagram refers to a diffuse pattern formed when many light rays emitted from one point pass through an optical system and their intersection with the image plane is no longer concentrated at the same point due to aberration. Instead, a diffuse pattern is formed over a certain range. The point diagram is mainly used to evaluate the imaging quality of the projection optical system.

[0146] 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.

[0147] Vertical axis chromatic aberration is also called magnification chromatic aberration. It mainly refers to the difference between the focal positions of blue light and red light on the image plane.

[0148] See also Figure 4 , the maximum value of the image point in the point diagram is less than 45μm.

[0149] See also Figure 5 , MTF is >0.4 at 19lp / mm.

[0150] See also Figure 6 ,The maximum distortion occurs in 1 field of view, and the absolute value is less than 45%.

[0151] See also Figure 7 , the maximum color difference value is less than 160μm.

[0152] Example 2

[0153] The near-eye optical system shown in this embodiment 2 is shown in FIG. Figure 8 , the basic optical architecture is the same, the differences are:

[0154] (1) The optical power φ1 of the first optical element is 0.03;

[0155] (2) The maximum optical aperture D of the near-eye optical system is 28 mm;

[0156] (3) The near-eye optical system satisfies the following conditions: sin(arctan(D / (2*T1)))*φ1*D=0.98;

[0157] The optical parameters of each optical element in the near-eye optical system of this embodiment 2 can be found in Table 2.

[0158] Table 2

[0159]

[0160] The optical performance of the near-eye optical system provided in Example 2 is demonstrated below through a dot array diagram, an MTF curve diagram, field curvature and distortion, and vertical axis chromatic aberration.

[0161] See also Figure 9, the maximum value of the image point in the point array diagram is less than 32μm.

[0162] See also Figure 10 , MTF is >0.2 at 19lp / mm.

[0163] See also Figure 11 ,The maximum distortion occurs in 1 field of view, and the absolute value is less than 40%.

[0164] See also Figure 12 , the maximum color difference value is less than 160μm.

[0165] Example 3

[0166] The near-eye optical system shown in this embodiment 3 is shown in FIG. Figure 13 , which differs from the near-eye optical system shown in the aforementioned embodiment 1 in that:

[0167] (1) The optical power φ1 of the first optical element is 0.01;

[0168] (2) The maximum optical aperture D of the near-eye optical system is 32.5 mm;

[0169] (3) The near-eye optical system satisfies the following conditions: sin(arctan(D / (2*T1)))*φ1*D=1.14;

[0170] The optical parameters of each optical element in the near-eye optical system of this embodiment 3 can be found in Table 3.

[0171] Table 3

[0172]

[0173] The optical performance of the near-eye optical system provided in Example 3 is demonstrated below through a dot array diagram, an MTF curve diagram, field curvature and distortion, and vertical axis chromatic aberration.

[0174] See also Figure 14 , the maximum value of the image point in the point diagram is less than 37μm.

[0175] See also Figure 15 , MTF is >0.2 at 19lp / mm.

[0176] See also Figure 16 ,The maximum distortion occurs in 1 field of view, and the absolute value is less than 40%.

[0177] See also Figure 17 , the maximum color difference value is less than 160μm.

[0178] According to another embodiment of the present application, a head-mounted display device is provided.

[0179] The head-mounted display device includes a housing and the near-eye optical system as described above.

[0180] 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.

[0181] 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, and therefore 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.

[0182] 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.

[0183] 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 for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above examples 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 polarizing reflection element (8), a phase retarder (7) and a beam splitter (6) arranged along the same optical axis, wherein the phase retarder (7) is located between the beam splitter (6) and the polarizing reflection element (8); The near-eye optical system further comprises a first optical element, the first optical element being located between the beam splitter (6) and the phase retarder (7), the first optical element being a lens group, and the optical power of the first optical element being φ1; The near-eye optical system satisfies: 0.98≤sin(arctan(D / (2*T1)))*φ1*D≤1.5; wherein the center interval between the light splitting element (6) and the polarized reflection element (8) is T1, and the maximum optical aperture of the near-eye optical system is D; The near-eye optical system further comprises a display screen (1); The near-eye optical system further comprises a second optical element, the second optical element being located between the display screen (1) and the beam splitting element (6), the second optical element comprising at least one lens, and the optical power of the second optical element being positive; The optical power φ1 of the first optical element is positive, and 0.005≤φ1≤0.

1.

2. The near-eye optical system according to claim 1, wherein: The near-eye optical system satisfies the following: 0.98≤sin(arctan(D / (2*T1)))*φ1*D≤1.

4.

3. The near-eye optical system according to claim 1, wherein: The first optical element comprises a first lens (5) and a second lens (4); The light splitting element (6) is arranged on the surface of the second lens (4) away from the first lens (5), and the phase delay device (7) and the polarization reflection element (8) are stacked and arranged on the surface of the first lens (5) away from the second lens (4).

4. The near-eye optical system according to claim 3, wherein: The curvature radius of the surface of the first lens (5) away from the second lens (4) is R, and R<0.

5. The near-eye optical system according to claim 4, wherein: The total optical power of the near-eye optical system is φ, and the near-eye optical system also satisfies: abs(1 / (R*φ))≤2.

6. The near-eye optical system according to claim 1, wherein: The edge spacing between the light splitting element (6) and the polarized reflection element (8) is T2, and the relationship between T2 and T1 satisfies: 0<(T2-T1) / (T2+T1)≤1.

7. The near-eye optical system according to any one of claims 1 to 6, characterized in that: The display screen (1) emits light for imaging display, and the display screen (1) is located on a side of the light splitting element (6) facing away from the first optical element.

8. The near-eye optical system according to claim 1, wherein: The second optical element is a third lens (3), and the optical power of the third lens (3) is positive.

9. The near-eye optical system according to claim 6, wherein: A polarizer (9) is provided on the side of the polarized reflective element (8) facing away from the phase retarder (7); The phase retarder (7), the polarization reflection element (8) and the polarizer (9) are stacked to form a composite film material.

10. The near-eye optical system according to claim 6, wherein: The display screen (1) is configured to emit circularly polarized light or natural light; In the case where the light emitted by the display screen (1) is natural light, the light-emitting surface of the display screen (1) is further 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.

11. A head-mounted display device, characterized in that: include: shell; as well as, The near-eye optical system according to any one of claims 1 to 10.

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