Optical module and head-mounted display device

Abstract

The embodiment of the present application provides an optical module and a head-mounted display device. The optical module comprises: a lens group, the lens group comprising at least one lens; the optical module further comprises a polarization element, a light splitting element and a phase retarder, and any side of the lens in the lens group is provided with the polarization element, the light splitting element and the phase retarder; the effective aperture B2 of the light splitting element is 45mm-65mm; the distance from the polarization element to the light splitting element is A2; the curvature radius of the light splitting element is C6; wherein the optical module satisfies 0.1 A2 / (C6 / 2)

Description

TECHNICAL FIELD

[0001] The present application relates to the field of near-eye display imaging technology, and more particularly, to an optical module and a head-mounted display device. BACKGROUND

[0002] In recent years, augmented reality (AR) technology and virtual reality (VR) technology have been applied in, for example, smart wearable devices and have rapidly developed. The core components of augmented reality technology and virtual reality technology are optical modules. The quality of the image displayed by the optical module will directly determine the quality of the smart wearable device.

[0003] In the pancake optical system design scheme, the distance between the polarization element and the light splitting element determines the foldable distance of the optical path and the degree of reduction of the total length of the system, but an excessively large distance will result in an excessively large aperture of the lens provided with the light splitting element, which adversely affects the overall miniaturization and compactness design of the pancake optical system.

[0004] Therefore, how to make the distance between the polarization element and the light splitting element more matched with the overall focal length of the pancake optical system to solve the overall miniaturization and compactness design of the pancake optical system is a technical problem to be solved at present. SUMMARY

[0005] The purpose of the present application is to provide a new technical solution of an optical module and a head-mounted display device.

[0006] In a first aspect, the present application provides an optical module, comprising:

[0007] a lens group comprising at least one lens;

[0008] The optical module further comprises a polarization element, a light splitting element, and a phase retarder, and the polarization element, the light splitting element, and the phase retarder are arranged on either side of the lens in the lens group;

[0009] The effective aperture B2 of the light splitting element is 45mm-65mm;

[0010] The distance from the polarization element to the light splitting element is A2, and the radius of curvature of the light splitting element is C6;

[0011] The optical module satisfies 0.1

[0012] Optionally, the distance A2 from the polarization element to the light splitting element is 8mm-17mm.

[0013] Optionally, the effective focal length range of the optical module is 15mm-35mm.

[0014] Optionally, the lens group comprises a first lens close to the side of the human eye, the first lens has a first surface towards the side of the human eye, and the first lens has a second surface towards the side of the display screen.

[0015] The polarization element is arranged on one side of the first surface, or the polarization element is arranged on one side of the second surface.

[0016] Optionally, the lens group comprises a lens close to the side of the display screen, and the light splitting element is arranged on the side of the lens close to the side of the display screen.

[0017] Optionally, the phase retarder comprises a first phase retarder.

[0018] The lens group comprises a first lens close to the side of the human eye, the first lens has a first surface towards the side of the human eye, and the first lens has a second surface towards the side of the display screen.

[0019] The first phase retarder is arranged on one side of the first surface, or the first phase retarder is arranged on one side of the second surface, wherein the first phase retarder is arranged closer to the side of the display screen relative to the polarization element.

[0020] Optionally, the phase retarder comprises a second phase retarder.

[0021] The lens group comprises a lens close to the side of the display screen, and the second phase retarder is arranged on the side of the lens close to the side of the display screen.

[0022] Optionally, the optical module further comprises a display screen, and the size of the display screen is D1.

[0023] The distance from the polarization element to the display screen is L1.

[0024] The effective aperture of the polarization element is B1.

[0025] Wherein the optical module satisfies: 0<(B1 / 2-D1 / 2) / L1<0.8.

[0026] Optionally, the distance L1 from the polarization element to the display screen is 12mm-25mm.

[0027] In a second aspect, a head-mounted display device is provided. The head-mounted display device comprises:

[0028] A housing; and

[0029] The optical module as claimed in the first aspect.

[0030] A technical effect of the present application is that by controlling the ratio of the distance between the polarizing element and the light splitting element and the half curvature radius of the light splitting element, the optical module has better compactness and the overall volume of the optical module is reduced.

[0031] Other features of the present specification, and the advantages thereof over existing prior art of the same or similar nature, will become apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings incorporated in and forming a part of the specification illustrate embodiments of the present specification and, together with the description, serve to explain the principles of the present specification.

[0033] Figure 1 The structure of the optical module provided by the present application is shown Figure 1 .

[0034] Figure 2 The structure of the optical module provided by the present application is shown Figure 2 .

[0035] Figure 3 The structure of the optical module provided by the present application is shown Figure 3 .

[0036] BRIEF DESCRIPTION OF DRAWINGS

[0037] 1, display screen; 2, lens group; 21, first lens; 22, second lens; 23, third lens; 3, polarizing element; 4, diaphragm; 5, light splitting element; 6, first phase retarder. DETAILED DESCRIPTION

[0038] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of the components and steps set forth in the embodiments, numerical expressions, and numerical values are not limiting to the scope of the present application unless otherwise specifically stated.

[0039] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting to the scope of the application or its applications or uses.

[0040] Techniques and equipment known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the specification where appropriate.

[0041] In all examples shown and discussed herein, any specific value should be interpreted as merely illustrative and not as a limitation. Thus, other examples of the exemplary embodiments can have different values.

[0042] It should be noted that like reference numerals and letters refer to like items throughout the several views, and once an item is defined in one view, it need not be discussed further in subsequent views.

[0043] In the pancake optical system design scheme, the pancake optical system design scheme utilizes the modulation effect of the polarization element on the polarized light to realize the restrictive transmission or reflection of light with a specific polarization state, thereby realizing the folding of the optical path. In the pancake optical system design scheme, the distance between the polarization element and the light splitting element determines the foldable distance of the optical path and the degree of reduction of the total length of the system, but too large a distance will result in an excessively large aperture of the lens provided with the light splitting element, which adversely affects the overall miniaturization and compactness design of the pancake optical system. Therefore, how to make the distance between the polarization element and the light splitting element more matched with the overall focal length of the pancake optical system to solve the overall miniaturization and compactness design of the pancake optical system is a technical problem to be solved at present.

[0044] Based on the above technical problem, a first aspect of the present application provides an optical module, which is a folded optical path optical structure design, can contain at least one optical lens, and can be applied to a head-mounted display (HMD), for example, a VR head-mounted device, such as a VR glasses or a VR helmet product, etc., which is not specifically limited in the embodiments of the present application.

[0045] The optical module and the head-mounted display device provided by the embodiments of the present application will be described in detail below. Figures 1 to 3 The optical module and the head-mounted display device provided by the embodiments of the present application will be described in detail below.

[0046] The embodiments of the present application provide an optical module, as shown in the accompanying drawings. Figures 1 to 3 As shown in the accompanying drawings, the optical module comprises a lens group 2, the lens group 2 comprising at least one lens. The optical module further comprises a polarization element 3, a light splitting element 5 and a phase retarder, and any side of the lens in the lens group 2 is provided with the polarization element 3, the light splitting element 5 and the phase retarder.

[0047] The effective aperture B2 of the light splitting element 5 is 45mm-65mm.

[0048] The distance between the polarization element 3 and the light splitting element 5 is A2, and the radius of curvature of the light splitting element 5 is C6. Wherein, the optical module satisfies 0.1

[0049] In other words, the optical module mainly comprises the lens group 2, the polarization element 3, the light splitting element 5 and the phase retarder.

[0050] The lens group 2 is configured to magnify the analysis light. For example, in a display device such as a virtual reality (VR) device, in order to ensure that the user obtains a magnified display image, the light needs to be magnified, and the lens group 2 is configured to ensure that the user obtains a magnified image that can be recognized. In the folded optical path, considering that the light has been folded, the number of lenses in the optical structure of the folded optical path can be at most three, compared with the direct optical structure.

[0051] Specifically, in order to achieve the folded optical path configuration, the polarization element 3, the light splitting element 5 and the phase retarder are arranged on any one side of the lens group 2. For example, the light splitting element 5 is arranged on the side of the lens group 2 facing the display screen 1; the polarization element 3 is arranged on the side of the lens group 2 away from the display screen 1, or the polarization element 3 is arranged on the side of one lens of the lens group 2; the phase retarder is arranged on the side of the lens group 2 facing the display screen 1, or the phase retarder is arranged on the side of one lens of the lens group 2.

[0052] The polarization element 3 can be configured to transmit P-polarized light and reflect S-polarized light, or the polarization element 3 can be configured to transmit S-polarized light and reflect P-polarized light. Specifically, the polarization element 3 has a polarization transmission direction, and light that vibrates along the polarization transmission direction can pass through the polarization element 3 smoothly, and light that vibrates in other directions is reflected by the polarization element 3 when encountering the polarization element 3. For example, the polarization element 3 can be a polarization reflection film or a reflective polarizer. In this embodiment, regardless of the position of the polarization element 3, the distance between the polarization element 3 and the light splitting element 5 is limited to A2.

[0053] The phase retarder can be configured to change the polarization state of the light in the folded optical path structure. For example, the phase retarder can be configured to convert linearly polarized light into circularly polarized light, or to convert circularly polarized light into linearly polarized light. For example, the phase retarder can be a quarter-wave plate.

[0054] When the light passes through the light splitting element 5, part of the light is transmitted and the other part of the light is reflected, without considering the absorption of the light. For example, the light propagating from the display screen 1 to the eye side can pass through the light splitting element 5, and the light propagating from the eye side to the display screen 1 is reflected by the light splitting element 5. The light splitting element 5 can be a half-reflective half-transmissive film or a polarizing film. In this embodiment, regardless of the position of the polarization element 3, the distance between the polarization element 3 and the light splitting element 5 is limited to A2, and the radius of curvature of the light splitting element 5 is limited to C6.

[0055] In this embodiment, A2 / (C6 / 2) is limited to be within the range, i.e. 0.1 < 2A2 / C6 < 0.5, while the effective aperture B2 of the light splitting element 5 is limited, so that the structure of the optical module has compactness. The effective aperture B2 of the light splitting element 5 can be: the effective aperture B2 of the lens on which the light splitting element 5 is arranged; or the effective aperture of the optical component on which the light splitting element 5 is arranged (the optical component is located between adjacent lenses, or the optical component is located between the lens and the display screen 1).

[0056] Specifically, the present embodiment does not particularly limit the specific arrangement position of the polarization element 3 and the light splitting element 5, but limits the distance between the polarization element 3 and the light splitting element 5 to be A2, i.e. the distance between the polarization element 3 and the light splitting element 5 on the optical axis is limited to be A2. The distance A2 between the polarization element 3 and the light splitting element 5 is an important factor for reducing the total length of the optical module system, and can make the light straighter and reduce the length of the light path by 2*A2.

[0057] The longer the folding light path of the light between the polarization element 3 and the light splitting element 5, the longer the distance between the polarization element 3 and the light splitting element 5, and the smaller the total optical length of the optical module, but the focal length of the optical module can be maintained within a certain range. Therefore, the ratio of A2 / (C6 / 2) is limited in this embodiment, so that the distance between the polarization element 3 and the light splitting element 5 and the system focal length of the optical module are reasonably matched.

[0058] The effective focal length of the optical module reflects the optical power of the optical module (the reciprocal of the total effective focal length of the optical module is the overall optical power of the optical module). In the pancake optical system design scheme (i.e. the optical module of the present application), the optical power of the entire system mainly comes from the curvature radius of the lens on which the light splitting element 5 is arranged, i.e. the optical power of the lens on which the light splitting element 5 is arranged is larger. Therefore, the ratio of A2 / (C6 / 2) is limited in this embodiment, so that the distance between the polarization element 3 and the light splitting element 5 and the effective focal length of the optical module are reasonably matched, so that the overall compactness of the optical module is better.

[0059] The optical power of the whole system is mainly contributed by the radius of curvature of the lens provided with the light splitting element 5, mainly because the light splitting element 5 reflects the light, and has a large deflection effect on the edge field of view and a large deflection effect on the central field of view, and the surface or lens where the polarization element 3 is located has a small contribution to the optical power, and the polarization effect of the light on the lens or surface provided with the polarization element 3 is small on the edge field of view. Therefore, the optical power of the whole system is mainly contributed by the radius of curvature of the lens provided with the light splitting element 5, rather than the radius of curvature of the lens provided with the polarization element 3. Therefore, the radius of curvature of the lens provided with the light splitting element 5 affects the overall focal length of the optical module.

[0060] In addition, considering that the longer the distance A2 between the light splitting element 5 and the polarization element 3 is, the larger the aperture B2 of the lens where the light splitting element 5 is located is, and the larger the aperture B2 of the lens where the light splitting element 5 is located is, the optical module system aperture is expanded, which has a negative effect on the miniaturization of the system.

[0061] Therefore, in summary, considering the mutual relationship of the focal length of the optical module, the radius of curvature of the light splitting element 5, and the distance between the polarization element 3 and the light splitting element 5, and considering the mutual relationship of the distance between the polarization element 3 and the light splitting element 5 and the effective aperture B2 of the light splitting element 5, the ratio of A2 / (C6 / 2) is limited to 0.1

[0062] It should be noted that in the embodiments of the present application, the ratio relationship between the distance between the polarization element 3 and the light splitting element 5 and the radius of curvature of the light splitting element 5 in the optical module can be flexibly adjusted according to specific needs, as long as the ratio relationship is controlled within a predetermined range.

[0063] For example, the range of A2 / (C6 / 2) can be 0.2-0.4.

[0064] For another example, the range of A2 / (C6 / 2) can be 0.25-0.35.

[0065] For another example, the range of A2 / (C6 / 2) can be 0.15-0.45.

[0066] Within the above-mentioned various ratio ranges, a compact optical module system can be achieved.

[0067] Of course, in the embodiments of the present application, the ratio relationship between the distance between the polarization element 3 and the light splitting element 5 and the radius of curvature of the light splitting element 5 in the optical module is not limited to the above-mentioned three examples, and can be flexibly adjusted according to needs by those skilled in the art, and the embodiments of the present application do not make specific limitations.

[0068] In an optional embodiment, the lens group 2 comprises at least two lenses.

[0069] In this embodiment, the lens group 2 is particularly limited to comprise at least two lenses. In the case that the lens group 2 only comprises one lens, the optical module only magnifies the light through one lens, and thus the distance between the one lens and the display screen 1 needs to be enlarged to ensure that all the incident light emitted by the display screen 1 is received by the one lens. In addition, the parameters of the lens need to be particularly limited to ensure the magnification of the light by the one lens. Therefore, in the case that the lens group 2 only comprises one lens, the compactness of the optical module is relatively poor. Therefore, in order to achieve better compactness, the case that the optical module only comprises one lens can not be considered, and the lens group 2 is limited to comprise at least two lenses in this embodiment.

[0070] In an embodiment, the distance between the polarization element 3 and the light splitting element 5 is 8-17 mm.

[0071] In this embodiment, the distance between the polarization element 3 and the light splitting element 5 is limited, that is, the length of the folded light path in the optical module is limited. In this embodiment, the length of the folded light path is limited, and the shorter the length of the folded light path, the greater the contribution to the shortening of the total optical length of the system. Compared with the direct light path, the folded light path of the present application reduces the light path by 16-34 mm, which can reduce the overall optical length of the optical module. For example, the distance A2 between the polarization element 3 and the light splitting element 5 can be 8-15 mm, or the distance A2 between the polarization element 3 and the light splitting element 5 can be 10-16.5 mm, or the distance A2 between the polarization element 3 and the light splitting element 5 can be 13-16 mm.

[0072] In addition, in this embodiment, the distance between the polarization element 3 and the light splitting element 5 is limited, so that the ratio of the distance A2 between the polarization element 3 and the light splitting element 5 to the half radius of curvature of the light splitting element 5 is limited in this range, to achieve the purpose of reducing the volume of the optical module and improving the compactness of the optical module.

[0073] In addition, the distance A2 between the polarization element 3 and the light splitting element 5 is limited in this embodiment, in combination with the effective aperture B2 of the light splitting element 5, so that the distance A2 between the polarization element 3 and the light splitting element 5 and the effective aperture of the light splitting element 5 are reasonably matched. For example, the ratio of the effective aperture B2 of the lens where the light splitting element 5 is located to the distance A2 between the polarization element 3 and the light splitting element 5, B2 / A2, can be 4-6, so that the compactness of the optical module and the effective aperture of the optical module are matched. The optical module has compactness, and the overall effective aperture of the optical module is not too large, and the optical module meets the requirements of lightness and miniaturization.

[0074] In this embodiment, the distance between the polarizing element 3 and the light splitting element 5 is 8mm-17mm, and the radius of curvature of one half of the surface of the light splitting element 5 is greater than 16mm and less than 170mm, i.e. the radius of curvature C6 of the light splitting element 5 is greater than 32mm and less than 340mm.

[0075] In one embodiment, the effective focal length of the optical module is 15mm-35mm.

[0076] In this embodiment, the effective focal length of the optical module is limited, i.e. the overall optical power of the optical module is limited. For example, the effective focal length of the optical module is 15mm-35mm, and the overall optical power of the optical module is 1 / 35-1 / 15.

[0077] In this embodiment, the focal length of the optical module is limited. The shorter the effective focal length of the optical module, the smaller the overall optical length of the optical module, and the greater the contribution of the folded optical path to the shortening of the optical length of the optical module, so that the optical module has better system compactness.

[0078] In one optional embodiment, the radius of curvature C6 of the light splitting element 5 is 50mm-145mm.

[0079] In this embodiment, the radius of curvature of the light splitting element 5 is limited, i.e. the radius of curvature of the surface on which the light splitting element 5 is located is limited. The radius of curvature of the surface on which the light splitting element 5 is located is positive, i.e. the overall optical power of the optical module can be basically embodied by the radius of curvature of the surface on which the light splitting element 5 is located (i.e. the main contribution of the overall optical power of the optical module comes from the radius of curvature of the surface on which the light splitting element 5 is located), and the overall optical power of the optical module is positive. For example, the surface of the lens on which the light splitting element 5 is located can be convex, which can better correct the field of view light.

[0080] In addition, in this embodiment, the radius of curvature of the surface on which the light splitting element 5 is located is limited, so that the ratio of the distance A2 between the polarizing element 3 and the light splitting element 5 to one half of the radius of curvature of the surface on which the light splitting element 5 is located is limited in this range, so as to achieve the purpose of reducing the volume of the optical module and improving the compactness of the optical module.

[0081] In one embodiment, the lens group 2 includes a first lens 21 close to the side of the human eye, the first lens 21 has a first surface facing the side of the human eye, and the first lens 21 has a second surface facing the side of the display screen.

[0082] The polarizing element 3 is arranged on one side of the first surface, or the polarizing element 3 is arranged on one side of the second surface.

[0083] In this embodiment, the lens group 2 includes one lens, two lenses, or three lenses, etc., and the lens group 2 includes a first lens 21 close to the human eye, i.e., the lens group 2 includes a first lens 21 arranged adjacent to the human eye, and the first lens 21 processes the light rays so that the processed light rays are output to the human eye and form an image.

[0084] Referring to Figure 1 and Figure 2 , the first lens 21 includes a first surface facing the human eye, and a polarization element 3 is arranged on one side of the first surface, e.g., the polarization element 3 can be arranged on the first surface, or the polarization element 3 is arranged between the human eye and the first surface, e.g., the polarization element 3 can be arranged between the human eye and the first surface by means of an optical component.

[0085] Referring to Figure 3 , the first lens 21 includes a second surface arranged away from the human eye, and a polarization element 3 is arranged on one side of the second surface, e.g., the polarization element 3 can be arranged on the second surface, or the polarization element 3 is arranged between the first lens 21 and a lens arranged adjacent to the first lens 21, e.g., the polarization element 3 can be arranged between the two adjacent lenses by means of an optical component.

[0086] The specific arrangement position of the polarization element 3 is not particularly limited in this embodiment, as long as the ratio of the distance from the polarization element to the light splitting element to the one-half of the curvature radius of the light splitting element is limited in the above range.

[0087] In one embodiment, referring to Figure 1 , Figure 3 , the lens group 2 includes a lens close to the display screen, and the light splitting element 5 is arranged on the near-display-screen side of the lens.

[0088] In this embodiment, the lens group 2 includes one lens, two lenses, or three lenses, etc., and the lens group 2 includes a lens close to the display screen 1, and the light rays emitted by the display screen 1 are first transmitted through the lens, and then the light rays are folded back, and finally transmitted to the human eye.

[0089] In this embodiment, the light splitting element 5 is arranged on the near-display-screen side of the lens close to the display screen 1. For example, the lens close to the display screen includes a surface facing the display screen, and the light splitting element 5 is arranged on the surface, or the light splitting element 5 is arranged between the surface and the display screen 1, e.g., the light splitting element 5 can be arranged between the surface and the display screen 1 by means of an optical component.

[0090] The specific setting position of the light splitting element 5 is not particularly limited in this embodiment, and only needs to satisfy the relationship that the distance between the polarizing element 3 and the light splitting element 5 and the ratio of the radius of curvature of the light splitting element 5 is limited in the above range.

[0091] In one embodiment, the phase retarder includes a first phase retarder 6; the lens group 2 includes a first lens 21 close to the human eye side, the first lens 21 has a first surface towards the human eye side, and the first lens 21 has a second surface towards the display screen side; the first phase retarder 6 is arranged on one side of the first surface, or the first phase retarder 6 is arranged on one side of the second surface, wherein the first phase retarder 6 is arranged closer to the display screen side relative to the polarizing element.

[0092] In this embodiment, the lens group 2 includes a first lens 21 close to the human eye side, regardless of whether the lens group 2 includes one lens, two lenses, or three lenses, etc. The lens group 2 includes the first lens 21 arranged adjacent to the human eye, and the first lens 21 processes the light to output the processed light to the human eye for imaging.

[0093] Referring to Figure 1 and Figure 2 , the first lens 21 includes a first surface towards the human eye, wherein the first phase retarder 6 is arranged on one side of the first surface, for example, the first phase retarder 6 can be arranged on the first surface, or the first phase retarder 6 is arranged between the human eye and the first surface, wherein the first phase retarder 6 can be arranged between the human eye and the first surface by means of an optical component.

[0094] Referring to Figure 3 , the first lens 21 includes a second surface arranged away from the human eye, wherein the first phase retarder 6 is arranged on one side of the second surface, for example, the first phase retarder 6 can be arranged on the second surface, or the first phase retarder 6 is arranged between the first lens 21 and the lens arranged adjacent to the first lens 21, for example, the first phase retarder 6 can be arranged between the two lenses arranged adjacent to each other by means of an optical component.

[0095] In this embodiment, the first phase retarder 6 is arranged closer to the display screen 1 relative to the polarizing element 3, for example, the polarizing element 3 and the first phase retarder 6 are arranged on the first surface of the first lens 21, wherein the first phase retarder 6 is arranged closer to the first lens 21 relative to the polarizing element 3; or the polarizing element 3 and the first phase retarder 6 are arranged on the second surface of the first lens 21, wherein the first phase retarder 6 is arranged farther away from the first lens 21 relative to the polarizing element 3.

[0096] Specifically, the polarization state of the light rays passing through the first phase retarder 6 is changed, wherein the light rays passing through the first phase retarder 6 for the first time are reflected by the polarizing element 3, the reflected light rays are processed by the light splitting element 5, and the light rays pass through the first phase retarder 6 again, wherein the light rays passing through the first phase retarder 6 for the second time are transmitted to the human eye by being transmitted by the polarizing element 3.

[0097] In one embodiment, the phase retarder comprises a second phase retarder; the lens group 2 comprises a lens close to the display screen side, and the second phase retarder is arranged on the near-display screen side of the lens.

[0098] In this embodiment, the lens group 2 comprises one lens, two lenses, or three lenses, etc., and the lens group 2 comprises a lens close to the display screen 1, i.e., the lens group comprises a lens arranged adjacent to the display screen 1, and the light rays emitted by the display screen 1 are transmitted through the lens first, then the light rays are folded, and finally transmitted to the human eye.

[0099] In this embodiment, the light splitting element 5 is arranged on the near-display screen side of the lens close to the display screen. For example, the lens close to the display screen comprises a surface facing the display screen, and the second phase retarder is arranged on the surface or between the surface and the display screen 1, for example, the second phase retarder can be arranged between the surface and the display screen 1 by means of an optical component. The second phase retarder is arranged closer to the display screen 1 than the light splitting element 5. Specifically, the light splitting element 5 and the second phase retarder are arranged on the surface of the lens close to the display screen 1 facing the display screen 1, and the second phase retarder is arranged closer to the display screen 1 than the light splitting element 5.

[0100] In one embodiment, referring to Figures 1 to 3 As shown in the figure, the optical module further comprises a display screen 1, and the size of the display screen 1 is D1. The distance between the polarizing element 3 and the display screen 1 is L1.

[0101] The effective aperture of the polarizing element 3 is B1. The optical module satisfies 0 < (B1 / 2-D1 / 2) / L1 < 0.8.

[0102] In this embodiment, the optical module further comprises a display screen 1, wherein the display screen 1 can be an LCD (Liquid Crystal Display), or an LED (Light Emitting Diode), an OLED (Organic Light-Emitting Diode), a Micro-OLED (Micro-Organic Light-Emitting Diode), an ULED (Ultra Light Emitting Diode), or a DMD (Digital Micro mirror Device), etc.

[0103] In this embodiment, the size of the display screen 1 is D1, wherein the size of the display screen 1 is defined as the maximum size of the area used for displaying the image, for example, the display screen 1 has an area for displaying the image, and the maximum size of the area is the size of the display screen 1.

[0104] In this embodiment, by limiting (B1 / 2-D1 / 2) / L1 within this range, the brightness uniformity of the displayed image is adjusted (the smaller the difference, the higher the uniformity, and the larger the difference, the lower the uniformity), so that the user observes the image at different viewing angles, and the brightness difference of the image at different viewing angles is smaller, that is, the user observes the image in the central region and the image in the edge region, and the brightness difference perceived by the user is smaller, and the user's eyes are not easily tired when observing the screen, and the user experience is improved.

[0105] Specifically, the polarization element 3 is the most critical and effective film layer for reflecting light in the folded light path, and the light emitted by the display screen 1 is folded between the polarization element 3 and the light splitting element 5. The polarization element 3 reflects the light rays of the image edge region of the display screen 1, which can basically correspond to the light rays of the edge field of view in the light source module. Specifically, the tangent value of the angle of the edge light is approximately equal to the ratio of the difference between the effective aperture B1 of the polarization element 3 and the size aperture of the display screen 1 to the distance L1 from the polarization element 3 to the display screen 1.

[0106] Therefore, in order to better simulate the angle of the light emitted in the image of the display screen 1 (because the angle cannot be accurately controlled), the effective aperture B1 of the polarization element 3, the distance L1 from the polarization element 3 to the display screen 1, and the size D1 of the display screen 1 are limited, and the relationship between the three parameters is that (B1 / 2-D1 / 2) / L1 can basically reflect the brightness relationship between the brightness of the light of the edge field of view and the brightness of the light of the central field of view.

[0107] Specifically, (B1 / 2-D1 / 2) / L1 is in this range, so that the polarization element 3 has a good matching effect with the display screen 1, and the effective aperture provided with the polarization element 3 has a better matching effect with the display screen 1. Specifically, (B1 / 2-D1 / 2) / L1 mainly adjusts the brightness of the edge field of view, so that the brightness of the edge field of view is controlled within 30% relative to the brightness of the central field of view, which meets the sensitivity of the human eye to observe the image brightness.

[0108] Therefore, in this embodiment, the optical module satisfies 0.1

[0109] In one embodiment, the distance L1 from the polarization element 3 to the display screen 1 is 12mm-35mm.

[0110] In this embodiment, in the optical module, no matter where the polarization element 3 is arranged in the optical module, the distance from the polarization element 3 to the display screen 1 needs to be in this range. This embodiment controls the distance from the polarization element 3 to the display screen 1, on the one hand, so that (B1 / 2-D1 / 2) / L1 satisfies 0

[0111] In addition, this embodiment limits the distance L1 from the polarization element 3 to the display screen 1, in combination with the distance A2 from the polarization element 3 to the light splitting element 5, so that the ratio of the distance L1 from the polarization element 3 to the display screen 1 to the distance A2 from the polarization element 3 to the light splitting element 5 can be limited, so that the optical module has a compact structure.

[0112] In an optional embodiment, the effective aperture B1 of the polarization element 3 is 44mm-63mm.

[0113] In this embodiment, the effective aperture of the polarization element 3 is limited, on the one hand, so that (B1 / 2-D1 / 2) / L1 satisfies 0

[0114] According to a second aspect of the embodiments of the present application, a head-mounted display device is provided. The head-mounted display device comprises a housing, and the optical module as described above.

[0115] The head-mounted display device is, for example, a VR head-mounted device, including a VR glasses or a VR helmet, and the embodiments of the present application do not make specific limitations thereto.

[0116] The specific implementation of the head-mounted display device of the embodiments of the present application can refer to the above-mentioned display module embodiments, which will not be repeated here.

[0117] The optical module provided by the embodiments of the present application is specifically described below through three embodiments.

[0118] Embodiment 1

[0119] Referring to Figure 1 The optical module provided by the embodiments of the present application includes a display screen 1, a first lens 21, a second lens 22, a polarization element 3, a light splitting element 5, and a diaphragm 4. The first lens 21 has a second surface facing the display screen 1 and a first surface away from the display screen 1. The second lens 22 has a first surface arranged adjacent to the first lens 21 and a second surface facing the display screen 1. The light splitting element 5 is arranged on the second surface of the second lens 22, and the polarization element 3 and a first phase retarder 6 are arranged on the first surface of the first lens 21. The diaphragm 4 is arranged at a position where the human eye is located.

[0120] The distance A2 between the polarization element 3 and the light splitting element 5 is 9.6088 mm, the curvature radius C6 of the surface on which the light splitting element 5 is located is 53.86 mm, the effective aperture B2 of the light splitting element 5 (wherein the light splitting element 5 is arranged on the second lens 22, and the effective aperture B2 of the second lens 22 is 46.34 mm) is 46.34 mm, the distance L1 between the polarization element 3 and the display screen 1 is 12 mm, the effective aperture B1 of the polarization element 3 (wherein the polarization element 3 is arranged on the first lens 21, and the effective aperture B1 of the first lens 21 is 44.5 mm) is 44.5 mm, and the size D1 of the display screen 1 is 26 mm. The effective focal length F of the optical module is 15.73 mm.

[0121] The optical parameters of the display screen 1, the first lens 21, the second lens 22, and the diaphragm 4 can refer to Table 1:

[0122]

[0123] The embodiment is adapted to 100° FOV and 26mm (small size screen) image plane size, A2 / (C6 / 2) of the embodiment is 0.357, and the effective aperture B2 of the light splitting element 5 is 46.34mm, so that the optical module has good compactness.

[0124] The embodiment is adapted to 100° FOV and 26mm image plane size, and the light incidence angle of the edge field of view is-41°, (B1 / 2-D1 / 2) / L1 of the embodiment is 0.77, so that the display brightness of the edge field of view is reduced by 30% compared with the brightness at 0° angle (central field of view), that is, the brightness of the edge field of view is reduced, and the uniformity of the brightness of the display screen 1 is improved.

[0125] Embodiment 2

[0126] Referring to Figure 2 The optical module provided by the embodiment of the application includes a display screen 1, a first lens 21, a second lens 22, a polarization element 3, a light splitting element 5 and a diaphragm 4, wherein the first lens 21 has a second surface facing the display screen 1 and a first surface away from the display screen 1; the second lens 22 has a first surface adjacent to the first lens 21 and a second surface facing the display screen 1; the light splitting element 5 is arranged on the second surface of the second lens 22, and the polarization element 3 and a first phase retarder 6 are arranged on the first surface of the first lens 21. The diaphragm 4 is arranged at a position where the human eye is located.

[0127] The distance A2 from the polarization element 3 to the light splitting element 5 is 8.2078mm, the curvature radius C6 of the surface on which the light splitting element 5 is located is 97.369mm, the effective aperture B2 of the light splitting element 5 (wherein the light splitting element 5 is arranged on the second lens 22, and the effective aperture B2 of the second lens 22 is 47.3mm) is 47.3mm, the distance L1 from the polarization element 3 to the display screen 1 is 20.89mm, the effective aperture B1 of the polarization element 3 (wherein the polarization element 3 is arranged on the first lens 21, and the effective aperture B1 of the first lens 21 is 47.6mm) is 47.6mm, and the size D1 of the display screen 1 is 38mm. The effective focal length F of the optical module is 23.68mm.

[0128] The optical parameters of the display screen 1, the first lens 21, the second lens 22 and the diaphragm 4 can be referred to Table 2:

[0129]

[0130]

[0131] The embodiment is adapted to 100° FOV and 38mm (medium size screen) image plane size, A2 / (C6 / 2) of the embodiment is 0.169, and the effective aperture B2 of the light splitting element 5 is 47.3mm, so that the optical module has good compactness.

[0132] The embodiment is adapted to 100° FOV and 38mm image plane size, and the light incidence angle of the edge field of view is-10°, (B1 / 2-D1 / 2) / L1 of the embodiment is 0.23, so that the display brightness of the light of the edge field of view is reduced by 20% compared with the brightness at 0° angle (central field of view), that is, the brightness of the light of the edge field of view is reduced, and the uniformity of the brightness of the display screen 1 is improved.

[0133] Embodiment 3

[0134] Referring to Figure 3 The optical module provided by the embodiment of the application comprises a display screen 1, a first lens 21, a second lens 22 and a third lens 23, wherein the first lens 21 is arranged farther away from the display screen 1 relative to the third lens 23, the third lens 23 is arranged adjacent to the display screen 1, and the second lens 22 is arranged between the first lens 21 and the third lens 23.

[0135] The first lens 21 has a first surface facing away from the second lens 22, and a second surface arranged adjacent to the second lens 22, the second lens 22 has a first surface arranged adjacent to the first lens 21, and a second surface arranged adjacent to the third lens 23, and the third lens 23 has a first surface arranged adjacent to the second lens 22, and a second surface arranged towards the display screen 1.

[0136] The polarization element 3 and the first phase retarder 6 are arranged on the second surface of the first lens 21, and the light splitting element 5 is arranged on the second surface of the third lens 23.

[0137] The distance A2 between the polarization element 3 and the light splitting element 5 is 16.089mm, the curvature radius C6 of the surface on which the light splitting element 5 is arranged is 142.42mm, the effective aperture B2 of the light splitting element 5 (wherein the light splitting element 5 is arranged on the third lens 23, and the effective aperture B2 of the third lens 23 is 62.44mm) is 62.44mm, the distance L1 between the polarization element 3 and the display screen 1 is 24.089mm, the effective aperture B1 of the polarization element 3 (wherein the polarization element 3 is arranged on the first lens 21, and the effective aperture B1 of the first lens 21 is 62.55mm) is 62.55mm, and the size D1 of the display screen 1 is 56mm. The effective focal length F of the optical module is 34.7mm.

[0138] The optical parameters of the display screen 1, the first lens 21, the second lens 22, the third lens 23 and the diaphragm 4 can be referred to Table 3.

[0139]

[0140] The embodiment is adapted to 100° FOV and 56mm (large size screen) image plane size, A2 / (C6 / 2) = 0.226 of the embodiment, and the effective aperture B2 of the light splitting element 5 is 62.44mm, so that the optical module has good compactness.

[0141] The embodiment is adapted to 100° FOV and 56mm image plane size, and the light ray incidence angle of the edge field of view is -8.62°, (B1 / 2-D1 / 2) / L1 = 0.136 of the embodiment, so that the display brightness of the edge field of view light ray is reduced by 15% compared with the brightness at 0° angle (central field of view), that is, the brightness of the edge field of view light ray is reduced, and the uniformity of the display screen 1 brightness is improved.

[0142] According to another aspect of the embodiment of the present application, a head-mounted display device is also provided, which comprises a housing and the optical module as described above.

[0143] In the above embodiments, the difference between the embodiments is mainly described, and the different optimization features between the embodiments can be combined to form a better embodiment as long as they are not contradictory. In view of the brevity of the writing, it will not be repeated here.

[0144] Although some specific embodiments of the present application have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration, and are not intended to limit the scope of the present application. Those skilled in the art should understand that the above embodiments can 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. An optical module, characterized in that, include: Lens group (2), the lens group (2) comprising at least two lenses; The optical module also includes a polarizing element (3), a beam splitting element (5), and a phase retarder. The polarizing element (3), the beam splitting element (5), and the phase retarder are provided on either side of the lens in the lens group (2). The beam splitter (5) is disposed on the surface of one of the lenses, and the effective aperture B2 of the lens is 45mm-65mm; The distance from the polarizing element (3) to the beam splitting element (5) is A2; the radius of curvature of the lens on which the beam splitting element (5) is provided is C6; Wherein, the optical module satisfies: 0.1 < A2 / (C6 / 2) < 0.5; The optical module also includes a display screen (1), the size of which is D1; The distance from the polarizing element (3) to the display screen (1) is L1; The polarizing element (3) is disposed on the surface of another lens, the effective aperture of which is B1; The tangent of the angle of the edge light rays of the optical module is approximated by (B1 / 2-D1 / 2) / L1. The optical module satisfies: 0 < (B1 / 2-D1 / 2) / L1 < 0.8, so as to adjust the brightness of the edge field of view of the optical module and control the decrease range of the brightness of the edge field of view relative to the brightness of the center field of view to be within 30%.

2. The optical module according to claim 1, characterized in that, The distance A2 between the polarization element (3) and the beam splitter (5) is 8mm-17mm.

3. The optical module according to claim 1, characterized in that, The effective focal length range of the optical module is 15mm-35mm.

4. The optical module according to claim 1, characterized in that, The lens group (2) includes a first lens (21) near the human eye side, the first lens (21) having a first surface facing the human eye side, and the first lens (21) having a second surface facing the display screen side; The polarizing element (3) is disposed on one side of the first surface or on one side of the second surface.

5. The optical module according to claim 1, characterized in that, The lens group (2) includes a lens near the display screen, and the beam splitting element (5) is disposed on the side of the lens near the display screen.

6. The optical module according to claim 1 or 4, characterized in that, The phase delayer includes a first phase delayer (6); The lens group (2) includes a first lens (21) near the human eye side, the first lens (21) having a first surface facing the human eye side, and the first lens (21) having a second surface facing the display screen side; The first phase delay unit (6) is disposed on one side of the first surface or on one side of the second surface, wherein the first phase delay unit (6) is disposed closer to the display screen side relative to the polarization element (3).

7. The optical module according to claim 1, characterized in that, The phase delayer includes a second phase delayer; The lens group (2) includes a lens near the display screen side, and the second phase delayer is disposed on the near display screen side of the lens.

8. The optical module according to claim 1, characterized in that, The distance L1 between the polarizing element (3) and the display screen (1) is 12mm-25mm.

9. A head-mounted display device, characterized in that, include: case; as well as The optical module as described in any one of claims 1-8.

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