Optical modules and head-mounted display devices

Abstract

The embodiments of the present application provide an optical module and a head-mounted display device. The optical module includes: a display screen having a size of D1; a lens group including at least one lens; the optical module also includes a polarizer, a beam splitter, and a phase retarder, wherein the effective aperture of the polarizer is B1; the polarizer, the beam splitter, and the phase retarder are disposed on either side of a lens in the lens group; the distance from the polarizer to the display screen is L1; wherein the optical module satisfies the following conditions: -0.2<(B1 / 2-D1 / 2) / L1<0.8.

Description

Technical Field

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

[0002] In recent years, augmented reality (AR) and virtual reality (VR) technologies, such as those used in smart wearable devices, have been rapidly applied and developed. The core components of both AR and VR technologies are optical modules. The quality of the images displayed by these modules directly determines the quality of smart wearable devices.

[0003] In current VR design schemes, the screens used mainly include LCD and OLED. These screens generally have the problem that the image brightness changes with the change of viewing angle. Specifically, as the viewing angle increases, the image brightness decreases.

[0004] When this type of screen is used in a VR optical module, when the user observes images from different viewing angles, the brightness of the screen itself changes with the viewing angle due to the different angles of incident light at different viewing angles. The brightness of the image will also change with the brightness of the screen itself, resulting in a strong contrast in the relative brightness of the image. Summary of the Invention

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

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

[0007] A display screen, wherein the size of the display screen is D1;

[0008] a lens group, wherein the lens group includes at least one lens;

[0009] The optical module further includes a polarizing element, a beam splitter and a phase retarder, wherein the effective aperture of the polarizing element is B1; the polarizing element, the beam splitter and the phase retarder are arranged on either side of the lens in the lens group;

[0010] The distance between the polarizing element and the display screen is L1;

[0011] The optical module satisfies: -0.2<(B1 / 2-D1 / 2) / L1<0.8.

[0012] Optionally, the optical module satisfies: -0.05<(B1 / 2-D1 / 2) / L1<0.8.

[0013] Optionally, the optical module satisfies: 7.5<β<19, where β is the field magnification.

[0014] Optionally, the lens group includes a lens arranged adjacent to the display screen, the lens has a surface facing the display screen, and the light splitting element is located on one side of the surface.

[0015] Optionally, the polarizing element is provided on a side of the lens group facing away from the display screen; or

[0016] The lens group includes at least two lenses, and the at least two lenses include a first lens closest to the human eye, wherein the first lens has a surface arranged away from the human eye, and the polarizing element is located on one side of the surface.

[0017] Optionally, the phase retarder includes a first phase retarder, which is arranged on a side of the lens group facing away from the display screen, and is arranged closer to the display screen than the polarization element;

[0018] The lens group includes at least two lenses, and the at least two lenses include a first lens closest to the human eye, wherein the first lens has a surface arranged away from the human eye, the first phase retarder is located on one side of the surface, and the first phase retarder is arranged farther away from the first lens relative to the polarization element.

[0019] Optionally, the phase delay device further includes a second phase delay device, the lens group includes a lens arranged adjacent to the display screen, the lens has a surface facing the display screen, the second phase delay device is located on one side of the surface, and the second phase delay device is arranged closer to the display screen relative to the spectroscopic element.

[0020] Optionally, the lens group includes a lens arranged adjacent to the display screen, and the optical power of the lens is positive.

[0021] Optionally, the distance from the polarizing element to the display screen satisfies: 10 mm < L1 < 35 mm.

[0022] Optionally, the effective aperture of the polarization element satisfies: 30 mm < B1 < 55 mm.

[0023] Optionally, the field of view angle range of the optical module is 80°≤FOV≤120°.

[0024] Optionally, the effective focal length range of the optical module is: 14mm<F<38.5mm.

[0025] In a second aspect, a head-mounted display device is provided. The head-mounted display device includes:

[0026] a housing; and

[0027] The optical module as described in the first aspect.

[0028] According to the embodiments of the present application, by limiting the difference between the effective aperture of the polarizing element provided in the optical module and the size of the display screen, and the ratio of the distance from the polarizing element to the display screen, it is possible to achieve a small difference in the relative brightness of the image when the user observes images at different viewing angles, thereby improving the user's visual viewing experience.

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

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

[0031] Figure 1 The figure shows the structure of the optical module provided in the embodiment of the present application. Figure 1 .

[0032] Figure 2 The figure shows the structure of the optical module provided in the embodiment of the present application. Figure 2 .

[0033] Figure 3 The figure shows the structure of the optical module provided in the embodiment of the present application. Figure 3 .

[0034] Description of reference numerals:

[0035] 1. Display screen; 2. Lens group; 21. First lens; 22. Second lens; 23. Third lens; 3. Polarization element; 4. Aperture; 5. Beam splitter; 6. First phase retarder. DETAILED DESCRIPTION

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] Existing technologies address the issue of display screen brightness varying with user viewing angles. Currently, the primary approach is to adjust the brightness of localized areas of the display screen through software, or to improve the internal structure of the display screen to meet appropriate relative brightness requirements. However, these existing approaches increase system energy consumption and design costs.

[0042] Based on the above technical problems, the first aspect of an embodiment of the present application provides an optical module, which is a folded light path optical structure design, which may include at least one optical lens and may be suitable for use in a head mounted display (HMD), for example, a VR head mounted device, such as VR glasses or VR helmets, etc., and no specific restrictions are imposed on this in the embodiment of the present application.

[0043] The following is combined with Figures 1 to 3 The optical module and head-mounted display device provided in the embodiments of the present application are described in detail.

[0044] The present application embodiment provides an optical module, such as Figures 1 to 3 As shown, the optical module includes: a display screen 1, a lens group 2, a polarization element 3, a beam splitter 5 and a phase retarder.

[0045] The display screen 1 has a size of D1. The lens assembly 2 includes at least one lens. The optical module further includes a polarizer 3, a beam splitter 5, and a phase retarder. The effective aperture of the polarizer 3 is B1. The distance between the polarizer 3 and the display screen 1 is L1. The optical module satisfies the following condition: -0.2 < (B1 / 2 - D1 / 2) / L1 < 0.8.

[0046] In other words, the optical module mainly includes a display screen 1, a lens group 2, a polarizing element 3, a beam splitter 5 and a phase retarder.

[0047] The display screen 1 can be an LCD display screen or an OLED display screen. Even though the image brightness of the display screen 1 changes with the user's viewing angle, the present application controls and limits the relationship between the effective aperture B1 of the polarizing element 3, the size D1 of the display screen 1, and the distance L1 between the polarizing element 3 and the display screen 1. Therefore, after the display screen 1 displays an image, the difference between the display brightness in the center area of the display screen 1 and the display brightness in the edge area of the display screen 1 is small, thereby improving the display effect.

[0048] The lens group 2 includes at least one lens, for example, Figure 1-Figure 3 As shown, the lens group 2 may include one lens, two lenses, or three lenses, etc. The optical design of the folded light path is realized by the optical architecture of one lens, two lenses or three lenses. In this embodiment, no matter how the optical architecture of the lens group 2 is designed, that is, no matter how the light in the folded light path is folded and transmitted, the lens closest to the human eye transmits the light to the human eye, and the light can enter the human eye to display the image. In this way, the human eye can see the complete picture. In this embodiment, as long as the limitation of the parameter relationship of the embodiment of the present application is met, the difference in the display brightness in the central area of the display screen 1 and the display brightness in the edge area of the display screen 1 can be reduced, and the human eye visually observes that the brightness difference of the image is small, thereby obtaining a better experience effect.

[0049] In order to realize the folded optical path design, a polarizing element 3, a beam splitter 5 and a phase retarder are provided in the optical module. For example, a polarizing element 3, a beam splitter 5 and a phase retarder are provided on either side of the lens in the lens group 2.

[0050] Specifically, to achieve a folded optical path, a polarizing element 3, a beam splitter 5, and a phase retarder are disposed on either side of a lens in lens group 2. For example, the beam splitter 5 is disposed on the side of lens group 2 facing the display screen 1; the polarizing element 3 is disposed on the side of lens group 2 facing away from the display screen 1, or on one side of a lens in lens group 2; and the phase retarder is disposed on the side of lens group 2 facing the display screen 1, or on one side of a lens in lens group 2.

[0051] The polarizing element 3 can be used to transmit P-polarized light and reflect S-polarized light; alternatively, the polarizing reflective element can be used to transmit S-polarized light and reflect P-polarized light. Specifically, the polarizing element 3 has a polarization transmission direction. Light can only pass smoothly through the polarizing element 3 when vibrating along the polarization transmission direction. Light vibrating in other directions is reflected when encountering the polarizing element 3. For example, the polarizing element 3 can be a polarizing reflective film or a reflective polarizer. In this embodiment, regardless of the location of the polarizing element 3, the distance from the polarizing element 3 to the display screen 1 is defined as L1, and the effective aperture of the polarizing element 3 is defined as B1.

[0052] The phase retarder can be used to change the polarization state of light in a folded optical path structure. For example, it can convert linearly polarized light into circularly polarized light, or vice versa. For example, the phase retarder can be a quarter-wave plate.

[0053] When light passes through the beam splitter 5, some light is transmitted and some is reflected. This does not take into account any absorption of light. For example, light traveling from the display screen 1 to the eye can pass through the beam splitter 5, while light traveling from the eye to the display screen 1 is reflected by the beam splitter 5. The beam splitter 5 can be a semi-reflective or translucent film or a polarizing film.

[0054] In this embodiment, the size of the display screen 1 is D1, where the size of the display screen 1 is: the maximum size of the screen for displaying an image, for example, the display screen 1 has an area for displaying an image, and the maximum size of the area.

[0055] In this embodiment, (B1 / 2-D1 / 2) / L1 is limited to this range, and 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 when the user observes images with different viewing angles, the brightness difference of the images at different viewing angles is smaller, that is, when the user observes the image in the central area and the image in the edge area, the visually perceived brightness difference is smaller, the user's eyes are not easily tired when observing the screen, and the user experience is improved.

[0056] Specifically, the polarizing element 3 serves as the most critical and effective film layer for reflecting light in the folded optical path. The direction of light in the edge area of the image of the display screen 1 reflected by the polarizing element 3 can basically correspond to the direction of light in the edge field of view in the light source module. Specifically, the tangent value of the angle of the edge light is approximately the ratio of the difference between the effective aperture B1 where the polarizing reflective film 3 is provided and the size D1 of the display screen 1, and the distance L1 from the polarizing reflective film 3 to the display screen 1.

[0057] Therefore, in order to better simulate the incident angle of light emitted by the image on the display screen 1 (because the incident angle cannot be accurately controlled), this embodiment limits the effective aperture B1 of the polarization element 3, the distance L1 between the polarization element 3 and the display screen 1, and the size D1 of the display screen 1. The relationship between these three parameters enables (B1 / 2-D1 / 2) / L1 to basically reflect the brightness relationship between the light brightness of the edge field of view and the light brightness of the center field of view.

[0058] Specifically, (B1 / 2 - D1 / 2) / L1 is within this range, ensuring a good match between the polarizing element 3 and the display screen 1, and also ensuring a good match between the effective aperture of the polarizing element 3 and the display screen 1. Specifically, (B1 / 2 - D1 / 2) / L1 primarily adjusts the brightness of the peripheral viewing field, keeping the brightness drop in the peripheral viewing field relative to the central viewing field within 30%, meeting the sensitivity of the human eye in observing image brightness.

[0059] Compared with the method of improving the internal structure of the display screen 1 in the prior art, and compared with the method of adjusting the brightness of the displayed image by software in the prior art, this embodiment controls the difference between the effective aperture of the polarization element 3 in the optical module and the size D1 of the display screen 1, and the ratio of the distance between the polarization element 3 and the display screen 1, so that when the user observes images at different viewing angles, the relative brightness difference of the image is small, thereby improving the user's visual viewing experience.

[0060] In one embodiment, the optical module satisfies: -0.05<(B1 / 2-D1 / 2) / L1<0.8.

[0061] In this embodiment, the range of (B1 / 2-D1 / 2) / L1 in the optical module is further narrowed and limited, wherein the smaller the value of (B1 / 2-D1 / 2) / L1, the smaller the difference between the image brightness in the central area and the image brightness in the edge area, that is, the uniformity of the image brightness in the central area and the image brightness in the edge area is good.

[0062] It should be noted that in the embodiments of the present application, those skilled in the art can flexibly adjust the difference between the effective aperture of the polarization element 3 provided in the optical module and the size of the display screen 1, and the ratio of the distance from the polarization element 3 to the display screen 1 according to specific needs, as long as the ratio is controlled within a preset range.

[0063] For example, (B1 / 2-D1 / 2) / L1 may be in the range of 0 to 0.8.

[0064] For another example, (B1 / 2-D1 / 2) / L1 may be in the range of 0.1 to 0.5.

[0065] For another example, (B1 / 2-D1 / 2) / L1 may be in the range of -0.1 to 0.1.

[0066] Within the above-mentioned ratio ranges, when a user observes an image at different viewing angles, the brightness difference of the image is small, and the brightness of the image further meets the uniformity requirement.

[0067] Of course, in the embodiments of the present application, the ratio of the difference between the effective aperture of the polarization element 3 provided in the optical module and the size of the display screen 1 and the distance from the polarization element 3 to the display screen 1 is not limited to the above three examples. Those skilled in the art can flexibly adjust them as needed, and the embodiments of the present application do not impose specific restrictions on this.

[0068] In one embodiment, the optical module satisfies: 7.5<β<19, where β is the field magnification.

[0069] Specifically, in VR design solutions, optical modules are used in VR designs to magnify the image displayed on display screen 1. Since different people experience different virtual image distances when using VR products, it is inaccurate to use the ratio of virtual image size to screen display size as a measure of the magnification capability of the VR optical module. In addition, we also know that optical modules are used in VR designs to not only magnify the displayed image but also magnify the viewing angle (for example, a magnifying glass magnifies an object). The magnification of the viewing angle does not change with different user conditions, so the viewing angle magnification ratio can be used as a parameter to measure the magnification capability of the VR system.

[0070] In this embodiment, the range of the viewing angle magnification (vertical axis magnification β) of the optical module is limited, so that the optical module meets the viewing angle magnification requirements from the size of a small display screen 1 to the size of a large display screen 1.

[0071] Specifically, the viewing angle magnification (the viewing angle magnification of the optical module is related to the magnification of each lens in lens assembly 2) is related to parameters such as the effective aperture of the lens, the focal length of the optical module, and the total optical length of the optical module, and theoretically determines the performance of the optical module. For example, a larger effective aperture of a lens results in higher resolution, a greater available magnification, and a smaller focal length, which can increase the field of view.

[0072] This embodiment limits (B1 / 2-D1 / 2) / L1 to this range, and further limits the effective aperture of the polarization element 3, the size of the display screen 1, and the distance from the polarization element 3 to the display screen 1, thereby limiting the viewing angle magnification of the optical module to this range. While controlling the brightness of the edge field of view image, it provides better resolution and improves the fineness of the displayed image, giving users a better immersive experience.

[0073] For example, the optical module satisfies: 5<β<15, another example, the optical module satisfies: 1<β<8, and another example, the optical module satisfies: 3<β<12.

[0074] Within the above-mentioned ratio ranges, on the one hand, when a user observes an image at different viewing angles, the brightness difference of the image is small, and on the other hand, better resolution is provided.

[0075] In one embodiment, referring to Figure 1-Figure 3 As shown, the light splitting element 5 is provided between the display screen 1 and the lens group 2 .

[0076] In this embodiment, the arrangement position of the light splitting element 5 is limited, wherein the light splitting element 5 is arranged on the side of the lens group 2 facing the display screen 1 .

[0077] In a specific embodiment, the lens group 2 includes a lens closest to the display screen, which has a surface facing the display screen, and a beam splitter element 5 is disposed on the surface. For example, the beam splitter element 5 is attached to the surface.

[0078] In another specific embodiment, a beam splitter element 5 is provided between the lens group 2 and the display screen 1. For example, a polarization element carrying the beam splitter element 5 is provided between the lens group 2 and the display screen 1, and the beam splitter element 5 is provided on the polarization element.

[0079] It should be noted that those skilled in the art can reasonably adjust the location of the light-splitting element 5 as needed.

[0080] In one embodiment, referring to Figure 1-Figure 3 As shown, the polarizing element 3 is provided on the side of the lens group 2 facing away from the display screen 1; or

[0081] The lens group 2 includes at least two lenses, and the polarization element 3 is arranged between two adjacent lenses.

[0082] In this embodiment, reference Figure 1As shown, the lens group 2 includes one lens, one of which is a first lens 21. The polarizing element 3 can be disposed on a surface of the first lens 21 facing away from the display screen 1, or the polarizing element 3 can be disposed on a side of the first lens 21 facing away from the display screen 1 but not on the surface of the first lens 21. For example, the polarizing element can be disposed between the first lens 21 and the human eye, and the polarizing element can be disposed on the polarizing element.

[0083] Reference Figure 2 and Figure 3 As shown, the lens group 2 includes two lenses, including a first lens 21 and a second lens 22, wherein the first lens 21 is arranged farther away from the display screen 1 than the second lens 22. A polarizing element 3 is arranged on the surface of the first lens 21 facing away from the second lens 22.

[0084] It should be noted that those skilled in the art can reasonably adjust the location of the polarization element 3 as needed.

[0085] In one embodiment, the phase retarder comprises a first phase retarder 6, which is arranged between the polarization element and the lens in the lens group, or

[0086] The lens group includes at least two lenses, and the first phase retarder 6 is arranged between two adjacent lenses.

[0087] In this embodiment, reference Figure 1 As shown, a first phase retarder 6 is disposed on the side of the lens assembly facing away from the display screen 1, and a polarizing element 3 is disposed on the side of the lens assembly 2 facing away from the display screen 1, with the first phase retarder 6 located between the polarizing element and the lens assembly. That is, the first phase retarder 6 is located between the first lens 21 and the polarizing element 3. In other words, the first phase retarder 6 is disposed closer to the display screen 1 than the polarizing element 3.

[0088] Reference Figure 2 and Figure 3 As shown, lens assembly 2 includes two lenses, namely a first lens 21 and a second lens 22, wherein first lens 21 is positioned farther away from display screen 1 than second lens 22. A first phase retarder 6 is positioned between first lens 21 and second lens 22. For example, first phase retarder 6 may be positioned on a surface of second lens 22 adjacent to first lens 21, or on a surface of first lens 21 adjacent to second lens 22, or at a suitable location between first lens 21 and second lens 22.

[0089] It should be noted that those skilled in the art can reasonably adjust the location of the first phase retarder 6 as needed.

[0090] In one embodiment, the phase retarder further includes a second phase retarder, and the second phase retarder is located between the lens group and the display screen.

[0091] In this embodiment, the arrangement position of the second phase retarder is defined, wherein the second phase retarder is located on the light emitting surface side of the display screen, for example, between the lens group and the display screen.

[0092] In this embodiment, the lens group includes a lens arranged adjacent to the display screen, and the optical power of the lens is positive.

[0093] In this embodiment, the lens group includes a lens disposed adjacent to the display screen. The optical power of the lens is positive and the lens is a magnifying lens that magnifies the light emitted from the display screen.

[0094] For example, refer to Figure 1-Figure 3 As shown, the lens arranged adjacent to the display screen includes a first surface and a second surface, wherein the first surface is arranged away from the display screen and the second surface is arranged toward the display screen, the first surface is a plane or a concave surface, and the second surface is a convex surface.

[0095] In one embodiment, the distance between the polarizing element 3 and the display screen 1 satisfies: 10 mm < L1 < 35 mm.

[0096] In this embodiment, regardless of the position of the polarizing element 3 in the optical module, the distance between the polarizing element 3 and the display screen 1 must be within this range. This embodiment controls the distance between the polarizing element 3 and the display screen 1. On the one hand, (B1 / 2 - D1 / 2) / L1 is within the range of -0.2-0.8, thereby reducing the difference in brightness between the peripheral and central viewing fields. On the other hand, by controlling the distance between the polarizing element 3 and the display screen 1, the overall optical length of the optical module is limited to a certain range, thereby meeting the requirements of miniaturization and lightweighting.

[0097] In an optional embodiment, the distance L between the polarizing element 3 and the display screen 1 is: 12 mm ≤ L1 ≤ 20 mm; or the distance L between the polarizing element 3 and the display screen 1 is: 20 ≤ L1 ≤ 30.

[0098] In one embodiment, the effective aperture of the polarization element 3 satisfies: 30 mm < B1 < 55 mm.

[0099] In this embodiment, the effective aperture of the polarization element 3 is limited. On the one hand, the range of (B1 / 2-D1 / 2) / L1 is within the range of -0.2-0.8, thereby reducing the difference in brightness between the edge field of view light and the center field of view light. On the other hand, after the polarization element 3 processes the light, the processed light can better simulate the light in the edge field of view of the optical module, so that (B1 / 2-D1 / 2) / L1 can better reflect the transmission characteristics of the edge field of view light.

[0100] In one embodiment, the field of view angle range of the optical module is 80°≤FOV≤120°.

[0101] In this embodiment, the field of view angle range of the optical module is 80°≤FOV≤120°. The optical module is applied to a VR device having a large field of view angle. For example, the field of view angle FOV of the optical module is 100°.

[0102] In one embodiment, the optical module satisfies the following relationship: 14 mm < F < 38.5 mm, where F is the effective focal length of the optical module.

[0103] Specifically, optical modules are used in VR design, which actually magnifies the image. To clearly see small objects or details, objects need to be brought closer to the eye. This increases the viewing angle and creates a larger real image on the retina. However, objects too close to the eye become difficult to see clearly. Therefore, the image should not only have a sufficiently wide angle for the eye, but also be positioned at an appropriate distance.

[0104] Specifically, the viewing angle magnification ratio β=1+250 / F is used as a parameter to measure the magnification capability of the VR system. This embodiment limits the effective focal length range of the optical module, thereby improving the picture clarity while controlling the brightness of the edge field of view image.

[0105] For example, the optical module satisfies the following conditions: 15mm<F<30mm.

[0106] In an optional embodiment, the size range of the display screen 1 is: 20 mm ≤ D1 ≤ 60 mm.

[0107] In this embodiment, the size range of the display screen 1 is limited. On the one hand, the range of (B1 / 2-D1 / 2) / L1 is within the range of -0.2-0.8, reducing the difference in brightness between the edge field of view and the center field of view; on the other hand, the VR device is suitable for small display screens 1 as well as large display screens 1.

[0108] In an optional embodiment, the field of view angle of the optical module is 80°≤FOV≤120°, the optical module satisfies the following conditions: 14mm<F<38.5mm, and the size range of the display screen 1 is 20mm≤D1≤60mm. In this embodiment, the field of view angle of the optical module and the size range of the display screen 1 are limited, so that the VR device can be adapted to a small-sized display screen 1, a medium-sized display screen 1, and a large-sized display screen 1 while increasing the field of view angle.

[0109] In this embodiment, in actual use, the field of view (FOV) of the optical module can be limited to a preset angle, for example, the field of view (FOV) of the optical module can be 100°. By balancing the effective aperture of the polarizing element and the size D1 of the display screen 1, for example, a larger effective aperture of the polarizing element corresponds to a larger size D1 of the display screen 1, and a smaller effective aperture of the polarizing element corresponds to a smaller size D1 of the display screen 1, (B1 / 2-D1 / 2) / L1 is satisfied within the range of -0.2-0.8, thereby reducing the difference in brightness between the edge field of view and the center field of view.

[0110] In this embodiment, the effective focal length of the optical module is limited so that different sizes D1 of display screens 1 are matched with different field of view angles FOV. For example, if the size of the display screen 1 is smaller, it can be matched with a smaller field of view angle, or if the size of the display screen 1 is larger, it can be matched with a larger field of view angle, or a large field of view angle can be matched with a small screen, a medium screen or a large screen to enhance the user experience.

[0111] According to a second aspect of the embodiments of the present application, a head-mounted display device is provided, comprising: a housing; and the optical module described above.

[0112] The head-mounted display device is, for example, a VR head-mounted device, including VR glasses or a VR helmet, etc., and the embodiments of the present application do not impose specific restrictions on this.

[0113] The specific implementation of the head-mounted display device in the embodiment of the present application can refer to the above-mentioned embodiments of the display module and will not be repeated here.

[0114] The optical module provided in the embodiments of the present application is described in detail below through three embodiments.

[0115] Example 1

[0116] Reference Figure 1As shown, an optical module provided by an embodiment of the present application includes a display screen 1, a first lens 21, and an aperture 4. The first lens 21 has a second surface facing the display screen 1 and a first surface facing away from the display screen 1. A beam splitter 5 is provided on the second surface, and a polarizing element 3 and a first phase retarder 6 are provided on the first surface. The first phase retarder 6 is provided closer to the first lens 21 than to the polarizing element 3.

[0117] The effective aperture B1 of the polarizing element 3 is 48.57 mm (because the polarizing element 3 is disposed on the surface of the first lens 21, the effective aperture of the first lens 21 is also referred to as 48.57 mm). The size D1 of the display screen 1 is 60 mm. The distance L1 from the polarizing element 3 to the display screen 1 is 34.784 mm. The effective focal length F of the optical module is 37 mm, and the field magnification β of the optical module is 7.76.

[0118] The optical parameters of the display screen 1, the first lens 21, and the aperture 4 can be referred to as shown in Table 1:

[0119]

[0120] This embodiment is adapted to a 100° FOV and a 60mm (large screen) image plane size, with the incident angle of light at the edge of the field of view being 13°. In this embodiment, (B1 / 2 - D1 / 2) / L1 = -0.164. This reduces the brightness of light at the edge of the field of view by less than 20% compared to the brightness at a 0° angle (center field of view). This reduces the brightness of light at the edge of the field of view and improves the brightness uniformity of display screen 1.

[0121] It should also be noted that the optical module can be adapted to small-size screens, medium-size screens, and large-size screens by adjusting the relationship between the B1, D1, and L1 parameters.

[0122] Example 2

[0123] Reference Figure 2 As shown, the optical module provided by the embodiment of the present application includes a display screen 1, a first lens 21, a second lens 22 and an aperture 4, wherein the first lens 21 is arranged farther away from the display screen 1 than the second lens 22, and the first lens 21 has a first surface facing away from the display screen 1, and a second surface arranged adjacent to the second lens 22, and the second lens 22 has a first surface arranged adjacent to the first lens 21, and a second surface arranged toward the display screen 1. For example, a polarizing element 3 and a first phase retarder 6 are arranged on the second surface of the first lens 21. The first phase retarder 6 is arranged farther away from the first lens 21 than the polarizing element 3. A spectroscopic element 5 is arranged on the second surface of the second lens 22.

[0124] The effective aperture B1 of the polarizing element 3 is 54.4 mm (because the polarizing element 3 is disposed on the surface of the first lens 21, the effective aperture of the first lens 21 is also referred to as 54.4 mm). The size D1 of the display screen 1 is 56 mm (a large screen). The distance L1 from the polarizing element 3 to the display screen 1 is 32.83 mm. The effective focal length F of the optical module is 35.79 mm, and the field magnification β of the optical module is 7.98.

[0125] The optical parameters of the display screen 1, the first lens 21, the second lens 22 and the aperture 4 can be referred to as shown in Table 2:

[0126]

[0127] This embodiment is adapted to a 100° FOV and a 56mm (large screen) image plane size, with the incident angle of light at the edge of the field of view being 3.6°. In this embodiment, (B1 / 2 - D1 / 2) / L1 = -0.02. At this point, the display brightness of light at the edge of the field of view is controlled to be within 15% lower than the brightness at a 0° angle (center field of view). This reduces the brightness of light at the edge of the field of view and improves the brightness uniformity of the display screen 1.

[0128] Example 3

[0129] Reference Figure 3 As shown, the optical module provided by the embodiment of the present application includes a display screen 1, a first lens 21, a second lens 22 and an aperture 4, wherein the first lens 21 is arranged farther away from the display screen 1 than the second lens 22, and the first lens 21 has a first surface facing away from the display screen 1, and a second surface arranged adjacent to the second lens 22, and the second lens 22 has a first surface arranged adjacent to the first lens 21, and a second surface arranged toward the display screen 1. For example, a polarizing element 3 and a first phase retarder 6 are arranged on the second surface of the first lens 21. The first phase retarder 6 is arranged farther away from the first lens 21 than the polarizing element 3. A spectroscopic element 5 is arranged on the second surface of the second lens 22.

[0130] The effective aperture B1 of the polarizing element 3 is 31 mm (because the polarizing element 3 is disposed on the surface of the first lens 21, the effective aperture of the first lens 21 is also referred to as 31 mm). The size D1 of the display screen 1 is 20.7 mm (a small screen). The distance L1 from the polarizing element 3 to the display screen 1 is 10.2 mm. The effective focal length F of the optical module is 14.4 mm, and the field magnification β of the optical module is 18.36.

[0131] The optical parameters of the display screen 1, the first lens 21, the second lens 22 and the aperture 4 can be referred to as shown in Table 3:

[0132]

[0133] This embodiment is adapted to a 90° FOV and a 20.7mm (small screen) image plane size, with the incident angle of light at the edge of the field of view being -21.7°. In this embodiment, (B1 / 2 - D1 / 2) / L1 = 0.5. At this point, the display brightness of light at the edge of the field of view is controlled to be within 30% lower than the brightness at a 0° angle (center field of view). This reduces the brightness of light at the edge of the field of view and improves the brightness uniformity of the display screen 1.

[0134] According to another aspect of an embodiment of the present application, a head-mounted display device is further provided, comprising a housing and the optical module as described above.

[0135] 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.

[0136] Although some specific embodiments of the present invention 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 invention. It should be understood by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. An optical module, characterized in that: include: A display screen (1), wherein the size of the display screen (1) is D1; A lens group (2), the lens group (2) being located on a light-emitting surface side of the display screen (1), the lens group (2) comprising at least one lens; The optical module further comprises a polarizing element (3), a beam splitting element (5) and a phase retarder, wherein the effective aperture of the polarizing element (3) is B1; the polarizing element (3), the beam splitting element (5) and the phase retarder are arranged on either side of the lens in the lens group (2); The distance between the polarizing element (3) and the display screen (1) is L1; The optical module satisfies: -0.2<(B1 / 2-D1 / 2) / L1<0.8, so as to balance the brightness of the central field of view and the edge field of view of the display screen.

2. The optical module according to claim 1, wherein: The optical module satisfies: -0.05<(B1 / 2-D1 / 2) / L1<0.

8.

3. The optical module according to claim 1, wherein: The optical module satisfies the following condition: 7.5<β<19, where β is the field magnification.

4. The optical module according to claim 1, wherein: The lens group (2) comprises a lens arranged adjacent to the display screen (1), the lens having a surface facing the display screen (1), and the light splitting element (5) is located on one side of the surface.

5. The optical module according to claim 1, wherein: The polarizing element (3) is provided on a side of the lens group (2) facing away from the display screen (1); or The lens group (2) includes at least two lenses, and the at least two lenses include a first lens (21) closest to the human eye, wherein the first lens (21) has a surface arranged away from the human eye, and the polarizing element (3) is located on one side of the surface.

6. The optical module according to claim 1 or 5, wherein: The phase retarder comprises a first phase retarder (6), the first phase retarder (6) being arranged on a side of the lens group (2) facing away from the display screen (1), and the first phase retarder (6) being arranged closer to the display screen (1) relative to the polarization element (3); or The lens group (2) includes at least two lenses, and the at least two lenses include a first lens (21) closest to the human eye, wherein the first lens (21) has a surface arranged away from the human eye, the first phase retarder (6) is located on one side of the surface, and the first phase retarder (6) is arranged farther away from the first lens (21) relative to the polarization element (3).

7. The optical module according to claim 1 or 4, characterized in that: The phase retarder further includes a second phase retarder, the lens group (2) includes a lens arranged adjacent to the display screen (1), the lens having a surface facing the display screen (1), the second phase retarder is located on one side of the surface, and the second phase retarder is arranged closer to the display screen (1) relative to the light splitting element (5).

8. The optical module according to claim 1, wherein: The lens group (2) comprises a lens arranged adjacent to the display screen (1), and the optical focal length of the lens is positive.

9. The optical module according to claim 1, wherein: The distance between the polarizing element (3) and the display screen (1) satisfies the following condition: 10 mm < L1 < 35 mm.

10. The optical module according to claim 1, wherein: The effective aperture of the polarization element (3) satisfies the following conditions: 30 mm < B1 < 55 mm.

11. The optical module according to claim 1, wherein: The field of view angle range of the optical module is 80°≤FOV≤120°.

12. The optical module according to claim 1 or 11, wherein: The effective focal length range of the optical module is: 14mm<F<38.5mm.

13. A head-mounted display device, characterized in that: include: case; as well as The optical module according to any one of claims 1 to 12.

Images