Virtual image display system, electronic device, and vehicle

Abstract

A virtual image display system (100), an electronic device, and a vehicle. The virtual image display system comprises a display (1), a transflective mirror (3), and a beam splitter (2). A light emission surface (11) of the display (1) is used for emitting first circularly polarized light, and the light emission surface (11) faces the transflective mirror (3). The transflective mirror (3) is provided with an incident surface (31) and an emergent surface (32) facing away from each other, the incident surface (31) facing the display (1). The transflective mirror (3) is used for converting the first circularly polarized light incident on the incident surface (31) into second circularly polarized light, and emitting the second circularly polarized light by means of the incident surface (31). The transflective mirror (3) is also used for converting second circularly polarized light incident on the incident surface (31) into first linearly polarized light, and emitting the first linearly polarized light by means of the emergent surface (32). The beam splitter (2) is located between the display (1) and the transflective mirror (3), and is used for transmitting a portion of the first circularly polarized light emitted by the light emission surface (11), so that the first circularly polarized light irradiates the incident surface (31). The beam splitter (2) is also used for reflecting a portion of the second circularly polarized light emitted by the incident surface (31), so that the second circularly polarized light irradiates the incident surface (31). An included angle between a central normal line (21) of the beam splitter (2) and the incident surface (31) is greater than 45° and less than 90°.

Description

Virtual image display system, electronic device and vehicle

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on February 27, 2024, with application number 202420374635.7 and application name “Virtual Image Display System, Electronic Device and Vehicle”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of display technology, and in particular to a virtual image display system, electronic equipment, and vehicle. Background Art

[0003] Virtual image display systems project virtual images of objects into the user's field of view, making them easier to see. For example, a head-up display (HUD) system projects vehicle instrumentation and navigation information into the driver's field of view, allowing the driver to see them without having to look down at the instrument panel or central control display below the steering wheel.

[0004] In related art, a virtual image display system includes a display screen, a semi-transparent mirror, and a reflective polarizer, arranged in sequence. Light emitted from the display screen is folded between the semi-transparent mirror and the reflective polarizer, thereby shortening the optical path and, consequently, reducing the size of the virtual image display system. However, the virtual image projected by this virtual image display system exhibits ghosting, resulting in poor image quality. Summary of the Invention

[0005] The embodiments of the present application provide a virtual image display system, an electronic device, and a vehicle, which can improve the problem of ghosting of the virtual image projected by the virtual image display system, thereby improving the imaging quality.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] In a first aspect of the present application, a virtual image display system is provided, which includes a display, a transflective mirror and a spectroscope. The display has a light-emitting surface, which is used to emit a first circularly polarized light. The transflective mirror is located on one side of the display, and the light-emitting surface faces the transflective mirror. The transflective mirror has an incident surface and an exit surface facing each other, and the incident surface faces the display. The transflective mirror is used to convert the first circularly polarized light incident on the incident surface into a second circularly polarized light, and emit it through the incident surface. The transflective mirror is also used to convert the second circularly polarized light incident on the incident surface into a first linearly polarized light, and emit it through the exit surface. The spectroscope is located between the display and the transflective mirror. The spectroscope is used to transmit part of the first circularly polarized light emitted from the light-emitting surface, so that the first circularly polarized light is irradiated onto the incident surface. The spectroscope is also used to reflect part of the second circularly polarized light emitted from the incident surface, so that the second circularly polarized light is irradiated onto the incident surface.

[0008] In this configuration, part of the light emitted from the light-emitting surface of the display can pass through the beam splitter and illuminate the transflective mirror, where it is reflected back to the beam splitter. Part of the light reflected from the beam splitter will also be reflected back to the transflective mirror by the beam splitter and then emitted through the transflective mirror, forming a virtual image and realizing the screen display.

[0009] However, due to the limitations of the transflector's own performance, it is difficult for all the light reflected by the beam splitter to pass through the transflector. The portion of light that does not pass through the transflector will be reflected back by the transflector back to the beam splitter, and some of the light will be reflected back by the beam splitter back to the transflector and emitted through the transflector, forming ghost image 1. During the process of forming ghost image 1, some light still cannot pass through the transflector. This portion of light will be reflected back by the transflector back to the beam splitter, and some of the light will be reflected back by the beam splitter back to the transflector and emitted through the transflector, forming ghost image 2. Ghost image 1 and ghost image 2 will adversely affect the virtual image projected by the virtual image display system, resulting in poor image quality.

[0010] In an embodiment of the present application, the beam splitter has a central normal, which is perpendicular to the surface of the beam splitter used to reflect the second circularly polarized light, and the geometric center of the surface of the beam splitter used to reflect the second circularly polarized light is located on the central normal. The angle between the incident plane and the central normal is greater than 45° and less than 90°. In this way, after the light emitted from the display is reflected by the transflective mirror, the light path forming ghost image 1 and ghost image 2 will be separated from the light path forming the virtual image, thereby separating ghost image 1 and ghost image 2 from the virtual image, thereby reducing the adverse effects of ghost image 1 and ghost image 2 on the virtual image and improving imaging quality.

[0011] In an optional implementation, the angle between the incident plane and the central normal is greater than or equal to 50°, and less than or equal to 85°. On the one hand, when the angle between the incident plane and the central normal is less than 50°, the virtual image deviates from the central normal of the spectrometer by a large distance, and the virtual image will be deformed to a large extent, resulting in poor imaging quality. On the other hand, when the angle between the incident plane and the central normal is greater than 85°, the ghost image deviates from the virtual image by a large distance, and some ghost images cannot be well separated from the virtual image, resulting in poor imaging quality. Based on this, setting the angle between the incident plane and the central normal to be greater than or equal to 50° and less than or equal to 85° can improve imaging quality.

[0012] In one optional implementation, the incident surface has a first end and a second end in the first direction, the first end being tilted relative to the second end toward the beam splitter. The first direction is perpendicular to the central normal and parallel to the reference plane; the central normal lies within the reference plane, and the incident surface is perpendicular to the reference plane.

[0013] In an optional implementation, the center of the light-emitting surface is located within the reference plane, and the light-emitting surface is perpendicular to the reference plane. The two ends of the light-emitting surface in the first direction are the third end and the fourth end, respectively, and the third end and the first end are located on the same side of the reference line. The center of the light-emitting surface is located on the reference line, and the intersection of the center normal and the incident surface is located on the reference line. On this basis, the third end is tilted relative to the fourth end in a direction away from the spectrometer, that is, the light-emitting surface and the incident surface are tilted in the same direction relative to the center normal. In this way, the virtual image formed by the virtual image display system can be closer to being perpendicular to the center normal. In this way, it is beneficial to reduce the degree of deformation of the virtual image, thereby obtaining higher imaging quality.

[0014] In an optional implementation, the angle between the light emitting surface and the first direction is less than or equal to twice the angle between the incident surface and the first direction.

[0015] In one optional implementation, the center of the light-emitting surface is located on the side of the central normal closest to the second end, and the angle between the central normal and the reference line is less than or equal to twice the angle between the incident surface and the first direction. This arrangement can reduce the distance between the center of the virtual image formed by the virtual image display system and the central normal. This helps reduce the degree of virtual image distortion, thereby achieving higher imaging quality.

[0016] In one optional implementation, a display includes a display module and a first quarter-wave plate. The display module is configured to emit first polarized light. The first quarter-wave plate is positioned between the display module and the beam splitter and is configured to convert the first polarized light emitted by the display module into first circularly polarized light. The surface of the first quarter-wave plate facing away from the display module serves as a light-emitting surface.

[0017] In an optional implementation, the transflective mirror includes a second quarter-wave plate and a polarizing reflective film. The surface of the second quarter-wave plate closest to the beam splitter serves as the incident surface. The second quarter-wave plate is used to convert the first circularly polarized light into the second linearly polarized light, and to convert the second linearly polarized light into the second circularly polarized light, and to convert the second circularly polarized light into the first linearly polarized light. The second quarter-wave plate is located between the beam splitter and the polarizing reflective film. The polarizing reflective film is used to transmit the first linearly polarized light and to reflect the second linearly polarized light. In this arrangement, a portion of the first circularly polarized light emitted by the display, after passing through the beam splitter, will enter the second quarter-wave plate and be converted into the second linearly polarized light, which will then be irradiated onto the polarizing reflective film. The second linearly polarized light irradiated onto the polarizing reflective film will be reflected back by the polarizing reflective film to the second quarter-wave plate and converted into the second circularly polarized light, which will then be transmitted to the beam splitter. A portion of the second circularly polarized light transmitted onto the beam splitter will be reflected by the beam splitter back by the second quarter-wave plate and converted into the first linearly polarized light, which will then be emitted through the polarizing reflective film.

[0018] In an optional implementation, the transflective mirror further includes a substrate layer, and the polarizing reflective film is located between the second quarter-wave plate and the substrate layer, and the polarizing reflective film is connected to the second quarter-wave plate and the substrate layer. The substrate layer can provide support and protection for the polarizing reflective film.

[0019] In an optional implementation, the beam splitter is a curved mirror that is concave toward the display. The curved mirror can increase the size of the virtual image projected by the virtual image display system, thereby obtaining an enlarged virtual image.

[0020] In an optional implementation, the beam splitter is a free-form surface mirror, which is beneficial to improving imaging quality.

[0021] In an optional implementation, the spectroscope includes a light-transmitting mirror and a spectroscope film, wherein the spectroscope film is bonded to the light-transmitting mirror, and the spectroscope film is used to transmit part of the first circularly polarized light emitted from the light-emitting surface and to reflect part of the second circularly polarized light emitted from the incident surface.

[0022] In an optional implementation, the splitting ratio of the beam splitting film is 5:5.

[0023] The second aspect of the present application provides an electronic device, which includes the virtual image display system of the first aspect. The electronic device has the same technical effects as the virtual image display system provided in any embodiment of the first aspect, and will not be described in detail here.

[0024] The third aspect of the present application provides a vehicle, which includes the virtual image display system of the first aspect. The vehicle has the same technical effects as the virtual image display system provided in any embodiment of the first aspect, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a schematic diagram showing the principle of a virtual image display system provided by the related art;

[0026] FIG2 is a schematic diagram of an optical path for forming a virtual image in a virtual image display system provided by related art;

[0027] FIG3 is a schematic diagram of an optical path for forming a ghost image in a virtual image display system provided by the related art;

[0028] FIG4 is a schematic diagram of an optical path for forming a second ghost image in a virtual image display system provided by related art;

[0029] FIG5 is a schematic structural diagram of a virtual image display system provided in an embodiment of the present application;

[0030] FIG6 is a schematic structural diagram of a display provided in an embodiment of the present application;

[0031] FIG7 is a schematic structural diagram of a display provided in an embodiment of the present application;

[0032] FIG8 is a schematic structural diagram of a virtual image display system provided in an embodiment of the present application;

[0033] FIG9 is a schematic structural diagram of a spectrometer provided in an embodiment of the present application;

[0034] FIG10 is a schematic diagram of an optical path for forming a virtual image in a virtual image display system provided by an embodiment of the present application;

[0035] FIG11 is a schematic diagram of an optical path for forming a virtual image in a virtual image display system provided by an embodiment of the present application;

[0036] FIG12 is a schematic diagram of an optical path for forming a ghost image in a virtual image display system according to an embodiment of the present application;

[0037] FIG13 is a schematic diagram of an optical path for forming a second ghost image in a virtual image display system provided by an embodiment of the present application;

[0038] FIG14 is a schematic structural diagram of a virtual image display system provided in an embodiment of the present application;

[0039] FIG15 is a schematic structural diagram of a virtual image display system provided in an embodiment of the present application;

[0040] FIG16 is a schematic structural diagram of a virtual image display system provided in an embodiment of the present application;

[0041] FIG17 is a schematic structural diagram of a virtual image display system provided in an embodiment of the present application;

[0042] FIG18 is a schematic structural diagram of a virtual image display system provided in an embodiment of the present application;

[0043] FIG19 is a schematic structural diagram of a virtual image display system provided in an embodiment of the present application;

[0044] FIG20 is a schematic structural diagram of a transflective mirror provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0046] Hereinafter, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified with "first," "second," etc., may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0047] In addition, in this application, directional terms such as "upper" and "lower" are defined relative to the orientation of the components in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they can change accordingly according to changes in the orientation of the components in the drawings.

[0048] A virtual image display system is a display technology that uses optical principles to generate virtual images in the air. It is commonly used in fields such as flight simulators, car driving simulations, virtual reality (VR) experiences, and augmented reality (AR) applications. As shown in Figure 1, Figure 1 is a schematic diagram of the principle of a virtual image display system 01 provided by the related art. This display technology does not rely on a physical screen, but uses a series of complex optical components (such as curved mirrors) to guide the light emitted by the image display unit and construct an image that seems to be suspended in space. This image is a virtual image. The virtual image display system 01 can utilize the optical virtual image display magnification characteristics to obtain a larger display frame with a smaller volume. At the same time, since the imaging distance is often farther, it can provide users with a more comfortable viewing experience.

[0049] At present, the pancake architecture is a widely used technology route in the field of virtual image magnification display technology. It mainly uses polarization optics to fold the imaging light path to achieve the purpose of reducing the volume of the virtual image display system.

[0050] In the related art, see Figure 2, which is a schematic diagram of the optical path used by a virtual image display system 01 provided in the related art to form a virtual image. Virtual image display system 01 utilizes a pancake architecture and includes a display unit 011, a first quarter-wave plate 012, a semi-transparent mirror 013, a second quarter-wave plate 014, and a polarizing reflective film 015, arranged in sequence. Display unit 011 is configured to emit linearly polarized light, which is converted into first circularly polarized light by passing through first quarter-wave plate 012. A portion of the first circularly polarized light passes through semi-transparent mirror 013 and is converted into S-polarized light by passing through second quarter-wave plate 014. After impinging on polarizing reflective film 015, the S-polarized light is reflected by polarizing reflective film 015 onto second quarter-wave plate 014, where it is then converted into second circularly polarized light by second quarter-wave plate 014. Part of the second circularly polarized light is reflected by the semi-transparent mirror 013 onto the second quarter-wave plate 014 and then converted into P-polarized light by the second quarter-wave plate 014. The P-polarized light can pass through the polarizing reflective film 015 to form a virtual image for display.

[0051] However, as shown in Figure 3, which is a schematic diagram of the optical path of a virtual image display system 01 provided in the related art, ghost images are formed. Due to the inherent performance of the polarizing reflective film 015, the aforementioned P-polarized light cannot completely pass through the polarizing reflective film 015. Some of the P-polarized light is reflected by the polarizing reflective film 015 onto the second quarter-wave plate 014, where it is then converted into first circularly polarized light and irradiated onto the semi-transparent mirror 013. Part of the first circularly polarized light is reflected by the semi-transparent mirror onto the second quarter-wave plate 014, where it is then converted into S-polarized light. Part of the S-polarized light passes through the polarizing reflective film 015, thereby forming an inverted ghost image on the side of the polarizing reflective film 015 facing away from the semi-transparent mirror 013.

[0052] As shown in Figure 4, Figure 4 is a schematic diagram of the optical path of a virtual image display system 01 provided by the related art to form a second ghost image. Another portion of the S-polarized light will be reflected by the polarizing reflective film 015 onto the second quarter-wave plate 014, and then converted into second circularly polarized light by the second quarter-wave plate 014 and irradiated onto the semi-transparent mirror 013. Among them, part of the second circularly polarized light will be reflected by the semi-transparent mirror 013 onto the second quarter-wave plate 014, and then converted into P-polarized light by the second quarter-wave plate 014. This portion of P-polarized light can pass through the polarizing reflective film 015, and then form another inverted ghost image 2 between the semi-transparent mirror 013 and the second quarter-wave plate 014. Ghost images 1 and 2 will adversely affect the virtual image projected by the virtual image display system 01, resulting in poor image quality.

[0053] Based on this, referring to Figure 5, which is a schematic diagram of the structure of a virtual image display system 100 provided in an embodiment of the present application, the present application provides a virtual image display system 100 for reducing the adverse effects of ghost images 1 and 2 on the virtual image projected by the virtual image display system, thereby improving imaging quality.

[0054] The virtual image display system 100 includes a display 1, which can be a liquid crystal display (LCD), a light emitting diode (LED), an organic light emitting diode (OLED), or a combination thereof.

[0055] The following takes the display 1 being an LCD as an example to exemplify some embodiments of the present application.

[0056] The display 1 has a light emitting surface 11 , and the light emitting surface 11 is used for emitting first circularly polarized light.

[0057] 6 , which is a schematic diagram of the structure of a display 1 provided in an embodiment of the present application. The display 1 may include a display module 12 and a first quarter-wave plate 13 . The display module 12 is configured to emit first polarized light, and the first quarter-wave plate 13 is configured to convert the first polarized light emitted by the display module 12 into first circularly polarized light.

[0058] For example, as shown in FIG6 , the display module 12 has a display surface 121 and a back surface 122 that face each other. The first quarter-wave plate 13 is disposed on the side of the display surface 121 facing away from the back surface 122, and the first quarter-wave plate 13 is bonded to the display surface 121. In this case, the surface of the first quarter-wave plate 13 facing away from the display module 12 serves as the light-emitting surface 11. As a result, the first polarized light emitted by the display module 12 can enter the first quarter-wave plate 13, be converted into first circularly polarized light by the first quarter-wave plate 13, and then be emitted through the light-emitting surface 11.

[0059] As shown in Figure 7, Figure 7 is a schematic diagram of the structure of a display 1 provided in an embodiment of the present application. The display module 12 may include a display screen 123 and a polarizer 124. The display screen 123 is configured to emit unpolarized light. The polarizer 124 is located between the display screen 123 and the first quarter-wave plate 13, and is configured to convert the unpolarized light emitted by the display screen 123 into first polarized light. In this case, the unpolarized light emitted by the display screen 123 can be converted into first polarized light by the polarizer 124, and then converted into first circularly polarized light by the first quarter-wave plate 13, and then emitted through the light-emitting surface 11.

[0060] It is understandable that the polarizer 124 can be configured to be attached to the display screen 123 and the first quarter-wave plate 13 .

[0061] In some embodiments, referring to FIG5 , the virtual image display system 100 further includes a beam splitter 2 disposed on one side of the display 1. The beam splitter 2 is configured to transmit a portion of the first circularly polarized light emitted from the light-emitting surface 11 of the display 1. In other words, after the first circularly polarized light emitted from the display 1 is irradiated by the beam splitter 2, a portion of the first circularly polarized light can pass through the beam splitter 2.

[0062] For example, as shown in FIG8 , which is a schematic structural diagram of a virtual image display system 100 provided in an embodiment of the present application, the light-emitting surface 11 of the display 1 faces the beam splitter 2. For example, if the display 1 includes a first quarter-wave plate 13 and a display module 12, the first quarter-wave plate 13 is positioned between the display module 12 and the beam splitter 2. This facilitates the first circularly polarized light emitted by the display 1 to be incident on the beam splitter 2, thereby allowing a portion of the first circularly polarized light to pass through the beam splitter 2.

[0063] In some embodiments, as shown in FIG8 , the beam splitter 2 is a curved mirror that is concave toward the display 1. The curved mirror can increase the size of the virtual image projected by the virtual image display system 100, thereby obtaining a magnified virtual image. This facilitates viewing for the user and improves the user experience.

[0064] On this basis, the beam splitter 2 can be a free-form surface mirror. It is understood that the free-form surface mirror can effectively correct phase aberration, which is beneficial to improving imaging quality.

[0065] It is understandable that the beam splitter 2 may also be a plane mirror, which can be selected according to actual conditions and is not specifically limited in this application.

[0066] In some embodiments, referring to FIG9 , FIG9 is a schematic diagram of the structure of a beam splitter 2 provided in an embodiment of the present application. The beam splitter 2 includes a light-transmitting mirror 22 and a beam-splitting film 23 , and the beam-splitting film 23 is bonded to the light-transmitting mirror 22 .

[0067] The dichroic film 23 can be arranged between the light-transmitting mirror 22 and the display 1 (as shown in FIG8 ), or on the side of the light-transmitting mirror 22 away from the display 1 . The specific selection can be made according to actual conditions, and this application does not make any specific restrictions on this.

[0068] In the following, some embodiments of the present application are exemplarily described by taking the case where the dichroic film 23 is disposed on the side of the light-transmitting mirror 22 facing away from the display 1 as an example.

[0069] The first circularly polarized light emitted by the display 1 can strike the light-transmitting mirror 22, then pass through the light-transmitting mirror 22 and strike the diaphragm 23. The diaphragm 23 can transmit a portion of the first circularly polarized light. For example, the first circularly polarized light striking the diaphragm 23 can partially pass through the diaphragm 23, while the remaining portion is reflected by the diaphragm 23.

[0070] The splitting ratio of the splitter film 23 can be any one of 2:8, 3:7, 4:6 and 5:5, or the splitting ratio of the splitter film 23 can be other ratios. The specific selection can be made according to actual conditions, and this application does not make any specific limitation on this.

[0071] For example, the splitting ratio of the prismatic film 23 is 5:5, that is, the transmittance and reflectance of the prismatic film 23 are both 50%. In this case, the prismatic film 23 can be regarded as a semi-transmissive and semi-reflective film.

[0072] 5 , the virtual image display system 100 further includes a transflective mirror 3, which is located on one side of the display 1, with the light emitting surface 11 facing the transflective mirror 3. The transflective mirror 3 has an incident surface 31 and an exit surface 32 facing each other, with the incident surface 31 facing the display 1.

[0073] The transflective mirror 3 is capable of converting first circularly polarized light incident on the incident surface 31 into second circularly polarized light, which is then emitted through the incident surface 31. The transflective mirror 3 is also capable of converting second circularly polarized light incident on the incident surface 31 into first linearly polarized light, which is then emitted through the exit surface 32. In other words, first circularly polarized light incident on the incident surface 31 is converted by the transflective mirror 3 into second circularly polarized light, which is then reflected by the transflective mirror 3. Second circularly polarized light incident on the incident surface 31 is converted by the transflective mirror 3 into first linearly polarized light, which then passes through the transflective mirror 3 and is emitted through the exit surface 32.

[0074] As shown in Figure 5, the beam splitter 2 is located between the display 1 and the transflective mirror 3. On the one hand, the beam splitter 2 is used to transmit a portion of the first circularly polarized light emitted from the light output surface 11, so that the first circularly polarized light is irradiated onto the incident surface 31. On the other hand, the beam splitter 2 is used to reflect a portion of the second circularly polarized light emitted from the incident surface 31, so that the second circularly polarized light is irradiated onto the incident surface 31.

[0075] As shown in FIG10 , FIG10 is a schematic diagram of the optical path for forming a virtual image in a virtual image display system 100 provided in an embodiment of the present application. A portion of the first circularly polarized light emitted from the light-emitting surface 11 of the display 1 can pass through the beam splitter 2 and illuminate the incident surface 31 of the transflective mirror 3, where it is then converted by the transflective mirror 3 into second circularly polarized light, which is reflected by the transflective mirror 3 and emitted from the incident surface 31. Thereafter, the second circularly polarized light emitted from the incident surface 31 will irradiate the beam splitter 2, and a portion of the second circularly polarized light will be re-reflected by the beam splitter 2 onto the incident surface 31, where it is then converted by the transflective mirror 3 into first linearly polarized light, which passes through the transflective mirror 3 and is emitted from the exit surface 32. The first linearly polarized light emitted from the exit surface 32 can form a virtual image, thereby enabling the virtual image display system 100 to display a picture.

[0076] 8 , the transflector 3 includes a second quarter wave plate 33 and a polarizing reflective film 34, wherein the second quarter wave plate 33 is located between the polarizing reflective film 34 and the beam splitter 2. In this case, the surface of the second quarter wave plate 33 close to the beam splitter 2 is the incident surface 31.

[0077] Among them, the second quarter-wave plate 33 can convert the first circularly polarized light into the second linearly polarized light. That is, the first circularly polarized light irradiated on the second quarter-wave plate 33 will be converted by the second quarter-wave plate 33 into the second linearly polarized light and pass through the second quarter-wave plate 33. The second quarter-wave plate 33 can also convert the second linearly polarized light into the second circularly polarized light. That is, the second linearly polarized light irradiated on the second quarter-wave plate 33 will be converted by the second quarter-wave plate 33 into the second circularly polarized light and pass through the second quarter-wave plate 33. The second quarter-wave plate 33 can also convert the second circularly polarized light into the first linearly polarized light. That is, the second circularly polarized light irradiated on the second quarter-wave plate 33 will be converted by the second quarter-wave plate 33 into the first linearly polarized light and pass through the second quarter-wave plate 33.

[0078] In addition, the polarizing reflective film 34 can transmit the first linear polarized light and reflect the second linear polarized light. In other words, the first linear polarized light incident on the polarizing reflective film 34 can pass through the polarizing reflective film 34, while the second linear polarized light incident on the polarizing reflective film 34 is reflected by the polarizing reflective film 34.

[0079] As shown in FIG11 , FIG11 is a schematic diagram of the optical path for forming a virtual image in a virtual image display system 100 provided by an embodiment of the present application. A portion of the first circularly polarized light emitted from the light-emitting surface 11 of the display 1 can pass through the beam splitter 2 and illuminate the incident surface 31 of the second quarter-wave plate 33. Thereafter, the second linearly polarized light irradiating the polarizing reflective film 34 is converted by the second quarter-wave plate 33 into second linearly polarized light. The second linearly polarized light irradiating the polarizing reflective film 34 is then reflected by the polarizing reflective film 34 back to the second quarter-wave plate 33. The second circularly polarized light irradiating the beam splitter 2 is then reflected by the beam splitter 2 onto the incident surface 31 of the second quarter-wave plate 33. The second linearly polarized light irradiating the polarizing reflective film 34 is then converted by the second quarter-wave plate 33 into second circularly polarized light. The second linearly polarized light irradiating the polarizing reflective film 34 is then reflected by the polarizing reflective film 34 back to the second quarter-wave plate 33. The second circularly polarized light irradiating the beam splitter 2 is then reflected by the beam splitter 2 onto the incident surface 31 of the second quarter-wave plate 33. The second linearly polarized light irradiating the polarizing reflective film 34 is then converted by the second quarter-wave plate 33 into first linearly polarized light. The second linearly polarized light irradiating the polarizing reflective film 34 is then irradiated by the second quarter-wave plate 33. The first linearly polarized light irradiated onto the polarizing reflective film 34 can pass through the polarizing reflective film 34 to form a virtual image, so that the virtual image display system 100 can realize image display.

[0080] FIG12 is a schematic diagram of the optical path for forming ghost image 1 in a virtual image display system 100 according to an embodiment of the present application. Due to the performance limitations of the transflective mirror 3, some light emitted from the display 1 may form ghost image 1 along the optical path shown in FIG12 . For details, please refer to the description of the ghost image 1 formation process above and will not be repeated here.

[0081] FIG13 is a schematic diagram of the optical path for forming a second ghost image in a virtual image display system 100 according to an embodiment of the present application. Due to the performance limitations of the transflective mirror 3, some light emitted from the display 1 may form a second ghost image along the optical path shown in FIG13 . For details, please refer to the description of the second ghost image formation process above and will not be repeated here.

[0082] In some embodiments of the present application, referring to FIG8 , the beam splitter 2 has a central normal 21, wherein the central normal 21 is perpendicular to the surface of the beam splitter 2 for reflecting the second circularly polarized light, and the geometric center of the surface of the beam splitter 2 for reflecting the second circularly polarized light is located on the central normal 21. For example, when the beam splitter 2 includes a light-transmitting mirror 22 and a beam splitter film 23, the central normal 21 is perpendicular to the beam splitter film 23, and the geometric center of the beam splitter film 23 is located on the central normal 21.

[0083] It should be noted that, when the beam splitter 2 is a curved mirror, the surface of the beam splitter 2 used to reflect the second circularly polarized light is a curved surface. At this time, the central normal 21 is perpendicular to the surface of the beam splitter 2 used to reflect the second circularly polarized light, which means that the central normal 21 is perpendicular to the tangent plane at the intersection of the curved surface and the central normal 21.

[0084] On this basis, refer to Figure 14, which is a schematic structural diagram of a virtual image display system 100 provided in an embodiment of the present application. The angle θ between the incident surface 31 of the transflector 3 and the central normal 21 of the beam splitter 2 is greater than 45° and less than 90°. With this arrangement, after light emitted from the display 1 is reflected by the transflector 3, the optical paths forming ghost images 1 and 2 are separated from the optical path forming the virtual image, thereby separating ghost images 1 and 2 from the virtual image. This reduces the adverse effects of ghost images 1 and 2 on the virtual image, improving imaging quality.

[0085] In other embodiments of the present application, the angle θ between the incident surface 31 of the reflector 3 and the center normal 21 of the beam splitter 2 is greater than or equal to 50° and less than or equal to 85°. On the one hand, when the angle θ between the incident surface 31 and the center normal 21 is less than 50°, the virtual image deviates from the center normal 21 of the beam splitter 2 by a large distance, and the virtual image will be deformed to a large extent, resulting in poor imaging quality. On the other hand, when the angle θ between the incident surface 31 and the center normal 21 is greater than 85°, the ghost image deviates from the virtual image by a large distance, and some ghost images cannot be well separated from the virtual image, resulting in poor imaging quality. Based on this, setting the angle θ between the incident surface 31 and the center normal 21 to be greater than or equal to 50° and less than or equal to 85° can improve the imaging quality.

[0086] It is understood that the smaller the divergence angle of the display 1, the larger the angle θ between the incident surface 31 and the center normal 21 needs to be set. In other words, the smaller the inclination angle of the incident surface 31 relative to the beam splitter 2 can be set. In this way, ghost images can be better separated from virtual images, thereby improving imaging quality.

[0087] In some embodiments, as shown in FIG14 , the incident surface 31 is perpendicular to the reference surface S, and the light emitting surface 11 is perpendicular to the reference surface S. The center and the center normal 21 of the light emitting surface 11 are located within the reference surface S. That is, the reference surface S is the plane where the center and the center normal 21 of the light emitting surface 11 lie.

[0088] In this way, the center of the virtual image projected by the virtual image display system 100 can be kept within the reference plane S where the center normal 21 is located. This helps to reduce the degree of deformation of the virtual image, thereby achieving higher imaging quality.

[0089] For example, as shown in FIG15 , FIG15 is a schematic structural diagram of a virtual image display system 100 provided in an embodiment of the present application. The two ends of the incident surface 31 in the first direction are respectively a first end 311 and a second end 312, and the two ends of the light emitting surface 11 in the first direction are respectively a third end 111 and a fourth end 112. The first direction is perpendicular to the center normal 21, and the first direction is parallel to the reference plane S. In addition, the third end 111 and the first end 311 are located on the same side of the reference line L, wherein the center of the light emitting surface 11 is located on the reference line L, and the intersection of the center normal 21 and the incident surface 31 is located on the reference line L.

[0090] On this basis, the first end 311 is tilted relative to the second end 312 toward the direction closer to the beam splitter 2, and the third end 111 is tilted relative to the fourth end 112 toward the direction away from the beam splitter 2. In other words, the light emitting surface 11 and the incident surface 31 are tilted in the same direction relative to the center normal 21.

[0091] The angle α between the light-emitting surface 11 and the first direction is less than or equal to twice the angle β between the incident surface 31 and the first direction. This allows the virtual image formed by the virtual image display system 100 to be closer to being perpendicular to the central normal 21. This helps reduce the degree of virtual image distortion, thereby achieving higher imaging quality.

[0092] For example, as shown in Figure 16, which is a schematic structural diagram of a virtual image display system 100 provided in an embodiment of the present application, the angle α between the light-emitting surface 11 and the first direction is equal to twice the angle β between the incident surface 31 and the first direction. In this case, the virtual image formed by the virtual image display system 100 is perpendicular to the central normal 21, thus achieving higher imaging quality.

[0093] In some embodiments, referring to FIG. 17 , FIG. 17 is a schematic diagram of the structure of a virtual image display system 100 provided in an embodiment of the present application. The center of the light-emitting surface 11 is located on the side of the center normal 21 close to the second end 312, and the angle γ between the center normal 21 and the reference line L is less than or equal to twice the angle β between the incident surface 31 and the first direction. For example, the angle γ between the center normal 21 and the reference line L is equal to the angle β between the incident surface 31 and the first direction. For another example, the angle γ between the center normal 21 and the reference line L is equal to twice the angle β between the incident surface 31 and the first direction.

[0094] This arrangement reduces the distance between the center of the virtual image formed by the virtual image display system 100 and the center normal 21, thereby moving the eyebox closer to, and nearly perpendicular to, the center normal 21. The eyebox refers to the area where the user's pupil receives a clearly focused image. This helps minimize virtual image distortion, thereby achieving higher image quality.

[0095] For example, as shown in Figure 18, which is a schematic structural diagram of a virtual image display system 100 provided in an embodiment of the present application, the angle γ between the center normal 21 and the reference line L is equal to twice the angle β between the incident surface 31 and the first direction. In this case, the center of the virtual image formed by the virtual image display system is located on the center normal 21, thereby achieving higher imaging quality.

[0096] In other embodiments, see FIG19 , which is a schematic structural diagram of a virtual image display system 100 provided in an embodiment of the present application. The center of the light-emitting surface 11 is located on the side of the center normal 21 close to the second end 312, the angle α between the light-emitting surface 11 and the first direction is equal to twice the angle β between the incident surface 31 and the first direction, and the angle γ between the center normal 21 and the reference line L is equal to twice the angle β between the incident surface 31 and the first direction. In this case, the virtual image formed by the virtual image display system 100 is perpendicular to the center normal 21, and the center of the virtual image is located on the center normal 21. In this way, higher imaging quality can be obtained.

[0097] In this case, the distance H between the center of the light-emitting surface 11 and the center normal 21 satisfies: H = X*sinγ = X*sin2β = X*sin2α; where X is the distance between the intersection of the center normal 21 and the incident surface 31 and the center of the light-emitting surface 11, γ is the angle between the center normal 21 and the reference line L, β is the angle between the incident surface 31 and the first direction, and α is the angle between the light-emitting surface 11 and the first direction.

[0098] In some embodiments, referring to FIG. 20 , FIG. 20 is a schematic diagram of the structure of a transflective mirror 3 provided in an embodiment of the present application. The transflective mirror 3 further includes a substrate layer 35. A polarizing reflective film 34 is positioned between the second quarter-wave plate 33 and the substrate layer 35. The polarizing reflective film 34 is connected to the second quarter-wave plate 33 and the substrate layer 35. The substrate layer 35 can be made of a transparent material such as glass or acrylic, and can provide support and protection for the polarizing reflective film 34.

[0099] For example, as shown in FIG20 , the polarizing reflective film 34 is bonded to the substrate layer 35. For example, the polarizing reflective film 34 is bonded to the surface of the substrate layer 35 using an optical adhesive. In this way, the substrate layer 35 can provide better support for the polarizing reflective film 34, reducing the risk of wrinkles on the polarizing reflective film 34, thereby improving the optical performance of the transflective mirror 3.

[0100] In addition, the polarizing reflective film 34 may be bonded to the second quarter wave plate 33. For example, the polarizing reflective film 34 is bonded to the surface of the second quarter wave plate 33 by optical adhesive.

[0101] Some embodiments of the present application also provide an electronic device, which may be a head mounted display (HMD), a head up display (HUD), a flight simulator (CNFS), a tablet computer, a television, a projector, or other devices.

[0102] The electronic device includes the virtual image display system 100 in any of the above embodiments. The electronic device has the same technical effects as the virtual image display system 100 provided in any of the above embodiments, and will not be described in detail here.

[0103] Some embodiments of the present application further provide a vehicle, which includes the virtual image display system 100 in any of the above embodiments. The vehicle has the same technical effects as the virtual image display system 100 provided in any of the above embodiments, and will not be described in detail here.

[0104] The above is only a specific embodiment of the present application, but the scope of protection of this application is not limited to this. Any changes or substitutions within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A virtual image display system, characterized in that: include: A display having a light emitting surface for emitting first circularly polarized light; a transflective mirror, the transflective mirror being located on one side of the display, with the light emitting surface facing the transflective mirror; the transflective mirror having an incident surface and an exit surface facing each other, the incident surface facing the display; the transflective mirror being configured to convert the first circularly polarized light incident on the incident surface into second circularly polarized light, and to emit the light through the incident surface; and the transflective mirror being configured to convert the second circularly polarized light incident on the incident surface into first linearly polarized light, and to emit the light through the exit surface; a beam splitter, the beam splitter being located between the display and the transflective mirror; the beam splitter being configured to transmit a portion of the first circularly polarized light emitted from the light emitting surface so that the first circularly polarized light is irradiated onto the incident surface; and the beam splitter being configured to reflect a portion of the second circularly polarized light emitted from the incident surface so that the second circularly polarized light is irradiated onto the incident surface; The beam splitter has a central normal, and the angle between the incident surface and the central normal is greater than 45° and less than 90°.

2. The virtual image display system according to claim 1, wherein: An included angle between the incident surface and the center normal is greater than or equal to 50° and less than or equal to 85°.

3. The virtual image display system according to claim 1, wherein: Two ends of the incident surface in the first direction are respectively a first end and a second end, and the first end is inclined relative to the second end toward a direction close to the beam splitter; The first direction is perpendicular to the center normal and parallel to the reference plane; the center normal is located in the reference plane, and the incident plane is perpendicular to the reference plane.

4. The virtual image display system according to claim 3, wherein: The center of the light emitting surface is located within the reference plane, and the light emitting surface is perpendicular to the reference plane; the two ends of the light emitting surface in the first direction are respectively a third end and a fourth end, and the third end and the first end are located on the same side of a reference line; the center of the light emitting surface is located on the reference line, and the intersection of the center normal and the incident surface is located on the reference line; The third end is inclined relative to the fourth end toward a direction away from the beam splitter.

5. The virtual image display system according to claim 4, wherein: The included angle between the light emitting surface and the first direction is less than or equal to twice the included angle between the incident surface and the first direction.

6. The virtual image display system according to claim 4 or 5, characterized in that: The center of the light emitting surface is located on a side of the center normal line close to the second end, and an angle between the center normal line and the reference line is less than or equal to twice an angle between the incident surface and the first direction.

7. The virtual image display system according to any one of claims 1 to 5, characterized in that: The display comprises: a display module, wherein the display module is configured to emit first polarized light; a first quarter-wave plate, located between the display module and the beam splitter, and configured to convert the first polarized light emitted by the display module into the first circularly polarized light; Wherein, the surface of the first quarter-wave plate facing away from the display module is the light-emitting surface.

8. The virtual image display system according to any one of claims 1 to 5, characterized in that: The transflective mirror comprises: a second quarter-wave plate, wherein the surface of the second quarter-wave plate close to the beam splitter is the incident surface; the second quarter-wave plate is used to convert the first circularly polarized light into a second linearly polarized light, and to convert the second linearly polarized light into the second circularly polarized light, and to convert the second circularly polarized light into the first linearly polarized light; A polarizing reflective film, wherein the second quarter wave plate is located between the polarizing reflective film and the beam splitter; the polarizing reflective film is used to transmit the first linearly polarized light and to reflect the second linearly polarized light.

9. The virtual image display system according to claim 8, wherein: The transflective mirror further comprises: The substrate layer, the polarizing reflective film is located between the second 1 / 4 wave plate and the substrate layer, and the polarizing reflective film is connected to the second 1 / 4 wave plate and the substrate layer.

10. The virtual image display system according to claim 1, wherein: The beam splitter is a curved mirror and is concave toward the display.

11. The virtual image display system according to claim 10, wherein: The beam splitter is a free-form surface mirror.

12. The virtual image display system according to claim 10 or 11, characterized in that: The spectroscope comprises: Translucent mirror; A diaphragm is bonded to the light-transmitting mirror; the diaphragm is used to transmit part of the first circularly polarized light emitted from the light-emitting surface, and to reflect part of the second circularly polarized light emitted from the incident surface.

13. The virtual image display system according to claim 12, wherein: The splitting ratio of the beam splitting film is 5:

5.

14. An electronic device, characterized in that: The virtual image display system comprises the virtual image display system according to any one of claims 1 to 13.

15. A vehicle, characterized in that: The virtual image display system comprises the virtual image display system according to any one of claims 1 to 13.

Images