Virtual image display device and vehicle

Abstract

The present application discloses a virtual image display device and a vehicle, belonging to the field of display technology. The virtual image display device includes an image generation unit, an occlusion unit, an optical path folding unit, and an imaging unit. The image generation unit is configured to emit image light. The occlusion unit is located on the optical path between the image generation unit and the optical path folding unit, and the occlusion unit is configured to transmit at least part of the image light from the image generation unit to the optical path folding unit, and block at least part of the stray light from the optical path folding unit from being emitted to the optical path folding unit. The optical path folding unit is configured to direct the image light from the occlusion unit to the imaging unit. The imaging unit is configured to form a virtual image based on the image light from the optical path folding unit. This virtual image display device is beneficial to eliminating ghost images.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and particularly to a virtual image display device and a vehicle. Background Art

[0002] In people's daily lives, virtual image display devices are increasingly used.

[0003] In related technologies, a virtual image display device includes an image generation unit, an optical path folding unit, and an imaging unit. The image generation unit provides image light carrying image information. The optical path folding unit is configured to direct the image light to the imaging unit, and the imaging unit forms a virtual image based on the image light. A user can see the virtual image at an appropriate position.

[0004] When the virtual image display device displays a virtual image, stray light emitted from the image generation unit is directly incident on the human eye after multiple reflections between the above-mentioned units, forming a ghost image. When the user views the virtual image, the ghost image will be seen simultaneously, affecting the viewing effect of the user. Summary of the Invention

[0005] The present application provides a virtual image display device and a vehicle, which can eliminate or reduce the ghost image in the virtual image display device and improve the display effect.

[0006] On the one hand, the present application provides a virtual image display device, which includes an image generation unit, an occlusion unit, an optical path folding unit, and an imaging unit. The image generation unit is configured to emit image light. The occlusion unit is located on the optical path between the image generation unit and the optical path folding unit. The occlusion unit is configured to transmit at least part of the image light from the image generation unit to the optical path folding unit, and block at least part of the stray light from the optical path folding unit from being emitted to the optical path folding unit. The optical path folding unit is configured to direct the image light from the occlusion unit to the imaging unit. The imaging unit is configured to form a virtual image based on the image light from the optical path folding unit.

[0007] When the virtual image display device is imaging, in addition to the light rays that form a normal image on the image plane, there will also be a small amount of light rays that do not participate in normal imaging. This phenomenon is called stray light phenomenon. These harmful light rays that are superimposed on the image plane and do not participate in direct imaging can be called stray light. That is, in this application, the light rays emitted by the image generation unit that do not participate in normal imaging are called stray light. When the virtual image display device does not include an occlusion unit, the stray light from the image generation unit is directed (reflected to) the imaging unit by the optical path folding unit, and the stray light reflected by the imaging unit is then directed by the optical path folding unit to the imaging plane of the image generation unit. Then, the imaging plane of the image generation unit reflects the stray light to the optical path folding unit, and then successively passes through the optical path folding unit and the imaging unit and is reflected to the human eye. If the intensity of the stray light incident on the human eye is relatively high, the user will see obvious ghost images.

[0008] In this application, however, the stray light from the image generation unit passes through the occlusion unit and reaches the optical path folding unit. The optical path folding unit directs (reflects) the received stray light to the imaging unit. The imaging unit then reflects the stray light to the optical path folding unit, and via the optical path folding unit, it is directed to the occlusion unit again. A part of the stray light passes through the occlusion unit and reaches the image generation unit. The image generation unit then reflects the received stray light, passes through the occlusion unit and reaches the optical path folding unit, and is then directed by the optical path folding unit to the imaging unit, and finally is reflected by the imaging unit to the human eye again.

[0009] Compared with the case where the virtual image display device does not include an occlusion unit, since the occlusion unit can prevent at least a part of the stray light from the optical path folding unit from being emitted to the optical path folding unit, in the embodiments of this application, the intensity of the stray light reflected by the occlusion unit and reaching the optical path folding unit is relatively low, so that the intensity of the stray light incident on the human eye is significantly reduced, and the user will not see obvious ghost images, or even will not see ghost images, thereby improving the display effect of the virtual image display device.

[0010] In this application, the occlusion unit prevents at least a part of the stray light from the optical path folding unit from being emitted to the optical path folding unit, including: the occlusion unit absorbs and / or changes the propagation direction of a part of the stray light in the stray light from the optical path folding unit, so that it cannot reach the image generation unit, and / or, the occlusion unit absorbs and / or changes the propagation direction of a part of the stray light in the stray light reflected from the image generation unit to the optical path folding unit, so that it cannot reach the optical path folding unit.

[0011] In the present application, the reflection ability of the surface of the shielding unit close to the optical path folding unit is lower than that of the imaging surface of the image generation unit. Exemplarily, the reflection abilities of the surface of the shielding unit close to the optical path folding unit and the imaging surface are both represented by the specular component include (SCI) reflectance. Among them, the SCI reflectance of the surface of the shielding unit close to the optical path folding unit is measured under the condition of the combination of the shielding unit and the image generation unit.

[0012] Exemplarily, the SCI reflectance of the surface of the shielding unit close to the optical path folding unit does not exceed 2%. In this way, ghost images can be basically eliminated.

[0013] Optionally, the shielding unit includes any one of the following film layers: an antireflection and antiscratch layer, an antiglare layer, and a stacked antireflection and antiscratch layer and antiglare layer. Using these three film layers to reduce the reflection ability of the imaging surface of the image shielding unit is easy to implement and has low cost.

[0014] In some examples, when the shielding unit includes an antiglare layer, the internal haze of the antiglare layer is greater than the external haze of the antiglare layer. In this way, it is beneficial to improve the display clarity of the virtual image. In some examples, the antiglare layer has the function of anti-glare points. In this way, obvious bright points can be avoided in the virtual image display device, which is beneficial to improving the user viewing experience.

[0015] In some examples, the image generation unit includes a direct imaging image source or a projection imaging image source. Exemplarily, the direct imaging image source includes a liquid crystal display (LCD), an organic light-emitting diode (OLED) display, a light-emitting diode (LED) display, etc. The projection imaging image source includes a light source and a reflective spatial light modulator. The light source is used to generate a light beam, and the reflective spatial light modulator is used to modulate and reflect the light beam generated by the light source to obtain the image light. When the image generation unit includes a projection imaging image source, the image generation unit further includes a diffuser screen for transmitting the image light and forming a real image. Exemplarily, the reflective spatial light modulator includes a liquid crystal on silicon (LCoS) modulator or a micro-electro-mechanical system (MEMS) modulator, etc.

[0016] Optionally, the image generation unit may further include a polarization state conversion element, which is configured to convert the image light generated by the image source into a target polarization state. In this way, the type of the image source can be arbitrarily selected as needed, which is more convenient.

[0017] In some examples, the occlusion unit is attached to the imaging surface of the image generation unit. In this way, the space occupied by the occlusion unit is small, which is beneficial to the thinning of the virtual image display device. For a direct imaging image source, the imaging surface is the surface of the direct imaging image source facing the optical path folding unit. For a projection imaging image source, the imaging surface is the surface of the diffuser screen facing the optical path folding unit.

[0018] In other examples, the occlusion unit is arranged at a relative interval with respect to the imaging surface of the image generation unit, and can also play a role in reducing the reflectivity of stray light.

[0019] Optionally, the image light emitted by the image generation unit is linearly polarized light, circularly polarized light or elliptically polarized light.

[0020] Optionally, the optical path folding unit may adopt any one of the following structures:

[0021] The first type is a semi-transmissive semi-reflective film, which can transmit a part of the received light and reflect the other part of the light. This first structure has no requirement for the polarization state of the image light emitted by the image generation unit, and the image light emitted by the image generation unit can be linearly polarized light, circularly polarized light or elliptically polarized light.

[0022] The second type is a quarter-wave plate and a reflective polarizing film, which are sequentially located on the optical path of the image light emitted by the image generation unit and on the optical path of the image light emitted by the imaging unit.

[0023] The circularly polarized light or elliptically polarized light emitted by the image generation unit is converted into linearly polarized light in a first polarization direction by the quarter-wave plate, and the reflective polarizing film reflects the linearly polarized light in the first polarization direction from the quarter-wave plate back to the quarter-wave plate. The quarter-wave plate changes the linearly polarized light in the first polarization direction from the reflective polarizing film back into circularly polarized light or elliptically polarized light and then emits it to the imaging unit. The imaging unit reflects the received circularly polarized light or elliptically polarized light, changes it into linearly polarized light in a second polarization direction after passing through the quarter-wave plate, and then transmits it through the reflective polarizing film and emits it to the human eye to form a virtual image.

[0024] The third type is a quarter-wave plate, a reflective polarizing film and an absorptive polarizing film, which are sequentially located on the optical path of the image light emitted by the image generation unit and on the optical path of the image light emitted by the imaging unit.

[0025] The circularly polarized light or elliptically polarized light emitted by the image generation unit is converted into linearly polarized light in the first polarization direction through a quarter-wave plate. The reflective polarizing film reflects most of the linearly polarized light in the first polarization direction from the quarter-wave plate back to the quarter-wave plate. The quarter-wave plate converts the linearly polarized light in the first polarization direction from the reflective polarizing film back into circularly polarized light or elliptically polarized light and then emits it to the imaging unit. The absorptive polarizing film is used to absorb the linearly polarized light in the first polarization direction that passes through the reflective polarizing film. The imaging unit reflects the received circularly polarized light or elliptically polarized light, converts it into linearly polarized light in the second polarization direction after passing through the quarter-wave plate, and then sequentially passes through the reflective polarizing film and the absorptive polarizing film and emits it to the human eye to form a virtual image.

[0026] By providing the absorptive polarizing film, when the reflective polarizing film cannot completely reflect the linearly polarized light in the first polarization direction from the quarter-wave plate, the linearly polarized light passing through the reflective polarizing film can be absorbed, thereby preventing the image light emitted by the image generation unit from directly entering the human eye to form a real image, further avoiding interference with the virtual image, and improving the viewing effect of the user.

[0027] Fourth, an antireflection and antireflection film, a quarter-wave plate, and a reflective polarizing film. The antireflection and antireflection film, the quarter-wave plate, and the reflective polarizing film are sequentially located on the optical path of the image light emitted by the image generation unit and are sequentially located on the optical path of the image light emitted by the imaging unit. The propagation path of the image light in the fourth structure is substantially the same as the propagation path of the image light in the second structure.

[0028] Fifth, an antireflection and antireflection film, a quarter-wave plate, a reflective polarizing film, and an absorptive polarizing film. The antireflection and antireflection film, the quarter-wave plate, the reflective polarizing film, and the absorptive polarizing film are sequentially located on the optical path of the image light emitted by the image generation unit and are sequentially located on the optical path of the image light emitted by the imaging unit. The propagation path of the image light in the fifth structure is substantially the same as the propagation path of the image light in the third structure.

[0029] In some examples, the optical path folding unit has a reflective surface for reflecting at least a part of the image light from the shielding unit to the imaging unit. The angle between the reflective surface and the optical axis of the imaging unit ranges from 55 to 75 degrees. The angle between the optical axis of the image generation unit and the optical axis of the imaging unit ranges from 55 to 75 degrees.

[0030] When the reflecting surface and the imaging surface of the image generation unit satisfy the above angular relationship, the virtual image display device has good display performance. Here, the display performance includes distortion, binocular parallax, modulation transfer function (MTF), etc.

[0031] In some examples, the angle between the optical axis of the imaging unit and the horizontal plane is 0 - 5 degrees. Generally, the line of sight of the user when viewing the virtual image is approximately parallel to the horizontal plane. Therefore, setting the angle between the optical axis of the imaging unit and the horizontal plane to 0 - 5 degrees facilitates the user to view.

[0032] Optionally, the imaging unit includes a curved mirror or a lens.

[0033] Optionally, the virtual image display device further includes a housing. The housing has an observation window. The image generation unit, the optical path folding unit, and the imaging unit are all located inside the housing. The housing can protect each unit and integrate each unit through the housing, so as to facilitate the overall movement of the virtual image display device.

[0034] Optionally, the virtual image display device further includes a main processor. The main processor is used to send image data to the image generation unit, and the image generation unit is used to provide image light based on the received image data.

[0035] In some examples, the virtual image display device further includes a power supply for powering the main processor and the image generation unit.

[0036] In some examples, the virtual image display device is a desktop display device, such as a monitor and a television, etc.

[0037] On the other hand, the present application provides a vehicle, and the vehicle includes any one of the foregoing virtual image display devices. The virtual image display device is installed on the vehicle. Exemplarily, the vehicle includes but is not limited to an automobile, an airplane, a train, or a ship, etc. Description of the Drawings

[0038] Figure 1 is a schematic diagram of the usage state of a virtual image display device provided by an embodiment of the present application;

[0039] Figure 2 is a schematic diagram of the usage state of another virtual image display device provided by an embodiment of the present application;

[0040] Figure 3 is a schematic diagram of the usage state of yet another virtual image display device provided by an embodiment of the present application;

[0041] Figure 4 is a schematic diagram of the structure of a virtual image display device provided by an embodiment of the present application;

[0042] Figure 5 It is a schematic diagram of the structure of another virtual image display device provided by an embodiment of the present application and the formation process of the virtual image;

[0043] Figure 6 is Figure 5 a schematic diagram of the formation process of the ghost image of the virtual image display device in

[0044] Figure 7 It is a schematic diagram of the structure of another virtual image display device provided by an embodiment of the present application and the imaging optical path;

[0045] Figure 8 It is a schematic diagram of the structure of another virtual image display device provided by an embodiment of the present application;

[0046] Figure 9 It is a schematic diagram of the functions of a means of transportation provided by an embodiment of the present application. Detailed implementation manners

[0047] The virtual image display device provided by the embodiments of the present application will be introduced in detail below with reference to the accompanying drawings. This virtual image display device can be used for office work as an ordinary display (such as shown by 100a in Figure 1 ), and can also be used for home entertainment (as a TV) as a TV (such as shown by 100b in Figure 2 ), or can be used for in-vehicle display (such as shown by 100c in Figure 3 ), where the virtual image display device is installed on the seat of the vehicle or on the instrument panel of the vehicle). The physical size, display size, and resolution of the virtual image display device can be adjusted according to the usage scenario. In the present application, this virtual image display device can also be referred to as a virtual image display system, a display system, or a display device.

[0048] Figure 4 It is a schematic diagram of the structure of a virtual image display device provided by an embodiment of the present application. As shown in Figure 4 , this virtual image display device includes: an image generation unit 110, an occlusion unit 120, an optical path folding unit 130, and an imaging unit 140. The image generation unit 110 is used to emit image light. The occlusion unit 120 is located on the optical path between the image generation unit 110 and the optical path folding unit 130. The occlusion unit 120 is used to transmit at least part of the image light from the image generation unit 110 to the optical path folding unit 130, and to block at least part of the stray light from the optical path folding unit 130 from being emitted to the optical path folding unit 130. The optical path folding unit 130 is used to direct the image light from the occlusion unit 120 to the imaging unit 140. The imaging unit 140 is used to form a virtual image based on the image light from the optical path folding unit 130.

[0049] In the embodiments of the present application, image light refers to a light beam carrying image information. The image generation unit 110 may also be referred to as an image source. The imaging unit 140 performs imaging based on the received image light to generate an enlarged virtual image. The optical path folding unit 130 is used to change the propagation direction of the image light emitted by the image generation unit 110, so that the propagation path of the image light is folded and reaches the imaging unit 140, thereby reducing the volume of the virtual image display device.

[0050] In the embodiments of the present application, after the image light emitted by the image generation unit passes through the shielding unit, it reaches the optical path folding unit, and the optical path folding unit guides the received image light to the imaging unit. The imaging unit reflects the image light to the human eye, so that the user can view the virtual image.

[0051] Among the image light emitted by the image generation unit, most of it participates in normal imaging to form a target virtual image, while a small part does not participate in normal imaging, and this part of the light will form a ghost image. The ghost image is usually darker in brightness and is offset from the target virtual image. In the embodiments of the present application, this part of the image light that does not participate in normal imaging is called stray light. When the virtual image display device does not include a shielding unit, the stray light from the image generation unit is guided by the optical path folding unit to the imaging unit, and the stray light reflected by the imaging unit is then guided by the optical path folding unit to the imaging surface of the image generation unit. Then, the imaging surface of the image generation unit reflects the stray light to the optical path folding unit, and then passes through the optical path folding unit and the imaging unit in sequence and is reflected to the human eye. If the intensity of the stray light incident on the human eye is relatively large, the user will see an obvious ghost image.

[0052] However, in the embodiments of the present application, the stray light from the image generation unit passes through the shielding unit and reaches the optical path folding unit, and the optical path folding unit guides the received stray light to the imaging unit. The imaging unit then reflects the stray light to the optical path folding unit and guides it to the shielding unit again via the optical path folding unit. A part of the stray light passes through the shielding unit and reaches the image generation unit, and the image generation unit reflects the received stray light again, passes through the shielding unit and reaches the optical path folding unit, and is then guided by the optical path folding unit to the imaging unit, and finally is reflected to the human eye again by the imaging unit.

[0053] Compared with the case where the virtual image display device does not include a shielding unit, since the shielding unit can prevent at least a part of the stray light from the optical path folding unit from being emitted to the optical path folding unit, in the embodiments of the present application, the intensity of the stray light reflected by the shielding unit and reaching the optical path folding unit is relatively low, so that the intensity of the stray light incident on the human eye is significantly reduced, and the user will not see an obvious ghost image, or even will not see a ghost image, thereby improving the display effect of the virtual image display device.

[0054] The light shielding unit 120 prevents at least a part of the stray light from the optical path folding unit 130 from being emitted towards the optical path folding unit 130, including: the light shielding unit 120 absorbs and / or changes the propagation direction of a part of the stray light in the stray light from the optical path folding unit 130 so that it cannot reach the image generation unit 110, and / or, the light shielding unit absorbs and / or changes the propagation direction of a part of the stray light in the stray light reflected from the image generation unit 110 towards the optical path folding unit 130 so that it cannot reach the optical path folding unit 130.

[0055] In some examples, the reflection ability of the surface of the light shielding unit 120 close to the optical path folding unit 130 is lower than the reflection ability of the imaging surface of the image generation unit 110. Since the light shielding unit 120 can absorb and / or change the propagation direction of a part of the stray light, for the combination of the light shielding unit 120 and the image generation unit 110, the overall reflection ability (i.e., the reflection ability of the surface of the light shielding unit 120 close to the optical path folding unit 130) is reduced. In this way, less stray light is reflected from the light shielding unit 120 to the optical path folding unit, so that the intensity of the stray light incident on the human eye is lower.

[0056] In the embodiments of the present application, the reflection ability of the surface of the light shielding unit 120 close to the optical path folding unit 130 and the reflection ability of the imaging surface of the image generation unit 110 may refer to the SCI reflectivity. The fact that the reflection ability of the surface of the light shielding unit 120 close to the optical path folding unit 130 is lower than the reflection ability of the imaging surface of the image generation unit 110 means that the SCI reflectivity of the surface of the light shielding unit 120 close to the optical path folding unit 130 is lower than the SCI reflectivity of the imaging surface of the image generation unit 110.

[0057] Here, the SCI reflectivity refers to the reflectivity measured by the SCI measurement method. The reflectivity measured under the SCI measurement method is based on all the light rays reflected (including specular reflection and diffuse reflection) from the target object.

[0058] Figure 5 and Figure 6 is a schematic structural diagram of another virtual image display device provided by the embodiments of the present application. As Figure 5 and Figure 6As shown, the virtual image display device includes an image generation unit 110, an occlusion unit 120, an optical path folding unit 130, and an imaging unit 140. The image generation unit 110 is configured to emit image light. The occlusion unit 120 is located on the optical path between the image generation unit 110 and the optical path folding unit 130. The occlusion unit 120 is configured to transmit at least part of the image light from the image generation unit 110 to the optical path folding unit 130, and block at least part of the stray light from the optical path folding unit 130 from exiting towards the optical path folding unit 130. The optical path folding unit 130 is configured to direct the image light from the occlusion unit 120 to the imaging unit 140. The imaging unit 140 is configured to form a virtual image based on the image light from the optical path folding unit 130.

[0059] In some examples, the image generation unit 110 may be a direct imaging light source, for example, an LCD, an organic light-emitting diode, an OLED display, or an LED display. Here, the LED display may be a micro (micro) LED display, or a mini (mini) LED display, etc.

[0060] In other examples, the image generation unit 110 includes a projection imaging light source, and the projection imaging light source may be an optical engine (also known as a picture generation unit, PGU). The optical engine includes a light source and a reflective spatial light modulator. The light source is configured to generate a light beam, and the reflective spatial light modulator is configured to modulate and reflect the light beam to form image light. Exemplarily, the reflective spatial light modulator includes an LCoS modulator or a MEMS modulator. Optionally, in addition to the optical engine, the image generation unit 110 further includes a diffuser screen (not shown in the figure). The diffuser screen is configured to receive the light beam output by the optical engine and diffuse the received light beam (for example, perform diffuse reflection on the received light beam) to improve the imaging quality.

[0061] This application does not limit the structure of the image generation unit 110, as long as it can provide the aforementioned image light.

[0062] Optionally, when the light beam provided by the image generation unit 110 is two-dimensional image light, the virtual image seen by the user is a two-dimensional image. Or, when the light beam provided by the image generation unit 110 is three-dimensional image light, the virtual image seen by the user is a three-dimensional image.

[0063] In some examples, the image light emitted by the image generation unit 110 may be linearly polarized light, circularly polarized light, or elliptically polarized light.

[0064] When the polarization state of the image light emitted by the image source in the image generation unit 110 is different from the target polarization state required by the image generation unit 110, the image generation unit 110 may further include a polarization state conversion element for converting the image light generated by the image source into the target polarization state. The polarization state conversion element includes, but is not limited to, a quarter-wave plate, a P-polarizing plate, an S-polarizing plate, or a combination thereof (such as a 1 / 4 wave plate and a P-polarizing plate, a 1 / 4 wave plate and an S-polarizing plate). For example, by setting a quarter-wave plate on the surface of the LCD, the image light emitted by the LCD can be changed into circularly polarized light or elliptically polarized light.

[0065] In the embodiments of the present application, the shielding unit 120 may adopt any one of the following three film layer structures.

[0066] First, the shielding unit 120 includes an anti-reflection (AR) layer (also known as an anti-reflection layer or an anti-reflection layer). The AR layer can simultaneously reduce the specular reflection and diffuse reflection of the imaging surface of the image generation unit, thereby reducing the brightness of ghost images.

[0067] Second, the shielding unit 120 includes an anti-glare (AG) layer.

[0068] Third, the shielding unit 120 includes a stacked AR layer and AG layer. Among them, the AR layer and the AG layer may be arranged in sequence along the light-emitting direction of the image generation unit 110, or the AG layer and the AR layer may be arranged in sequence along the light-emitting direction of the image generation unit 110. The stacked AR layer and AG layer can simultaneously reduce the specular reflection and diffuse reflection of the imaging surface of the image generation unit, thereby reducing the brightness of ghost images. Exemplarily, for the shielding unit 120 using a stacked AR layer and AG layer, the SCI reflectivity of the surface close to the optical path folding unit is not greater than 2%, and the effect of eliminating ghost images can be achieved.

[0069] Here, the AR layer refers to a film layer that can increase the transmittance of light in the target wavelength range and reduce the reflectivity of light in the target wavelength range. The target wavelength range covers all wavelengths of light used by the image generation unit to carry image information.

[0070] In some examples, the AR layer may include a plurality of stacked sub-layers, and at least some of the sub-layers have different refractive indexes. Through the cooperation of the refractive indexes and thicknesses of the respective sub-layers, the reflectivity of light is reduced by using the interference effect. Exemplarily, the AR layer includes alternately stacked first sub-layer and second sub-layer, and the refractive indexes of the first sub-layer and the second sub-layer are different. For example, the first sub-layer may be a silicon dioxide (SiO 2 ) layer, and the second sub-layer may be a niobium pentoxide (Nb 2 O 5) layer. In the embodiments of the present application, the number and thickness of the sub-layers are not limited and can be set according to actual needs.

[0071] In some other examples, the AR layer can be a moth-eye film.

[0072] The AG layer refers to a film layer that reduces specular reflection of strong light sources. In some examples, the AG layer has an anti-sparkling function, and the internal haze of the AG layer is greater than or equal to the exterior haze of the AG layer. Here, the internal haze is caused by the refraction, reflection, scattering, etc. of light when passing through media with different refractive indices (scattering particles and coatings), which changes the traveling direction and causes a fogging effect; while the exterior haze is the fogging effect caused by the uneven surface of the film layer. When the internal haze of the AG layer is greater than or equal to the exterior haze of the AG layer, it is beneficial to improve the display clarity of the virtual image. When the AG layer has an anti-sparkling function, it can avoid obvious bright spots in the virtual image display device, which is beneficial to enhancing the user viewing experience.

[0073] Exemplarily, the AG layer can be obtained by surface treatment, and the surface treatment methods include but are not limited to doping particles and surface roughening, etc.

[0074] Using the shielding unit with the above structure to reduce the reflection ability of the imaging surface of the image shielding unit is easy to implement and has low cost.

[0075] In some other examples, the AG layer may also not have an anti-sparkling function or the internal haze of the AG layer is less than the exterior haze of the AG layer, as long as the virtual image can be displayed.

[0076] Optionally, the shielding unit 120 can be directly attached to the imaging surface of the image generation unit 110. For a direct imaging image source, the imaging surface is the surface of the direct imaging image source facing the optical path folding unit. For a projection imaging image source, the imaging surface is the surface of the diffuser screen facing the optical path folding unit. For example, depositing the AR layer or the AG layer directly on the surface of the direct imaging image source, or pasting the AR layer or the AG layer on the surface of the direct imaging image source through an optical adhesive. In this way, the space occupied by the shielding unit is small, which is beneficial to the thinning and lightening of the virtual image display device.

[0077] Alternatively, in other embodiments, the shielding unit 120 can be arranged at a relative interval with respect to the imaging surface of the image generation unit, and can also play a role in reducing the reflectivity of stray light.

[0078] When the first and third structures are adopted for the light shielding unit, if the AR layer or the AG layer is directly attached to the imaging surface of the image generation unit 110, the refractive index of the AR layer or the AG layer can be matched with the refractive index of the film layer structure near the imaging surface in the image generation unit 110, so as to further reduce the reflectivity of the imaging surface of the image generation unit 110.

[0079] In the embodiment of the present application, when the light shielding unit 120 is directly attached to the imaging surface of the image generation unit 110, the SCI reflectivity of the surface of the light shielding unit 120 close to the optical path folding unit does not exceed 2%. In this way, ghost images can be basically eliminated.

[0080] For example, for the light shielding unit 120 including only the AR layer, when the light shielding unit 120 is directly attached to the imaging surface of the image generation unit 110, the measured SCI reflectivity of its surface close to the optical path folding unit is not greater than 1%. The effect of eliminating ghost images can be achieved.

[0081] For another example, for the light shielding unit 120 including a stack of the AR layer and the AG layer, when the light shielding unit 120 is directly attached to the imaging surface of the image generation unit 110, the measured SCI reflectivity of its surface close to the optical path folding unit is not greater than 2%. The effect of eliminating ghost images can be achieved.

[0082] In the embodiment of the present application, the optical path folding unit 130 may include any one of the following structures:

[0083] The first type, as Figure 5 and Figure 6 shown, the optical path folding unit 130 includes a semi-transmissive and semi-reflective film, and the semi-transmissive and semi-reflective film is located on the optical path of the image light emitted by the image generation unit 110 and on the optical path of the image light emitted by the imaging unit 140.

[0084] The semi-transmissive and semi-reflective film can transmit a part of the image light and reflect a part of the image light. In the embodiment of the present application, the transmission and reflection ratios of the semi-transmissive and semi-reflective film are not limited. For example, a semi-transmissive and semi-reflective film with a transmittance of 90% and a reflectivity of 10% can be adopted; or, a semi-transmissive and semi-reflective film with a transmittance of 80% and a reflectivity of 20% can be adopted; or, a semi-transmissive and semi-reflective film with a transmittance of 70% and a reflectivity of 30% can be adopted; or, a semi-transmissive and semi-reflective film with a transmittance of 60% and a reflectivity of 40% can be adopted; or, a semi-transmissive and semi-reflective film with a transmittance of 50% and a reflectivity of 50% can be adopted, and so on.

[0085] A part of the image light emitted by the image generation unit 110 is reflected by the semi-transmissive and semi-reflective film to the imaging unit 140. The imaging unit 140 reflects the image light from the semi-transmissive and semi-reflective film back to the semi-transmissive and semi-reflective film again. The semi-transmissive and semi-reflective film transmits the image light from the imaging unit 140 and projects it onto the human eye, thereby forming a virtual image S1. Here, the image light emitted by the image generation unit 110 can be linearly polarized light, circularly polarized light, or elliptically polarized light.

[0086] Second, the optical path folding unit 130 includes a quarter-wave plate 131 and a reflective polarizing film 132. The quarter-wave plate 131 and the reflective polarizing film 132 are successively located on the optical path of the image light emitted by the image generation unit 110 and are successively located on the optical path of the image light emitted by the imaging unit 140.

[0087] Figure 7 FIG. is a schematic structural diagram and imaging optical path diagram of a virtual image display device using the optical path folding unit of the second structure. As Figure 7 shown, the circularly polarized light or elliptically polarized light emitted by the image generation unit 110 passes through the shielding unit 120 and reaches the quarter-wave plate 131. The quarter-wave plate 131 converts the circularly polarized light or elliptically polarized light into linearly polarized light (S light) in the first polarization direction. The reflective polarizing film 132 reflects the linearly polarized light (S light) in the first polarization direction from the quarter-wave plate back to the quarter-wave plate 131. The quarter-wave plate 131 converts the linearly polarized light (S light) in the first polarization direction from the reflective polarizing film 132 back into circularly polarized light or elliptically polarized light and then emits it to the imaging unit 140. The imaging unit 140 reflects the received circularly polarized light or elliptically polarized light, which becomes linearly polarized light (P light) in the second polarization direction after passing through the quarter-wave plate 131, and then passes through the reflective polarizing film 132 and is emitted to the human eye to form a virtual image.

[0088] It should be noted that in Figure 7 , for the convenience of showing the conversion of the polarization state of light, the quarter-wave plate 131 and the reflective polarizing film 132 are arranged at intervals, while in actual applications, the two are closely attached together.

[0089] Third, the optical path folding unit 130 includes a quarter-wave plate, a reflective polarizing film, and an absorptive polarizing film. The quarter-wave plate, the reflective polarizing film, and the absorptive polarizing film are successively located on the optical path of the image light emitted by the image generation unit 110 and are successively located on the optical path of the image light emitted by the imaging unit 140.

[0090] The circularly polarized light or elliptically polarized light emitted by the image generation unit is converted into linearly polarized light in the first polarization direction through a quarter-wave plate. The reflective polarizing film reflects most of the linearly polarized light in the first polarization direction from the quarter-wave plate back to the quarter-wave plate. The quarter-wave plate converts the linearly polarized light in the first polarization direction from the reflective polarizing film back into circularly polarized light or elliptically polarized light and then emits it to the imaging unit. The absorptive polarizing film is used to absorb the linearly polarized light in the first polarization direction that passes through the reflective polarizing film. The imaging unit reflects the received circularly polarized light or elliptically polarized light, converts it into linearly polarized light in the second polarization direction after passing through the quarter-wave plate, and then sequentially passes through the reflective polarizing film and the absorptive polarizing film and emits it to the human eye to form a virtual image.

[0091] By setting the absorptive polarizing film, it is possible to prevent the image light emitted by the image generation unit from directly entering the human eye to form a real image, further avoiding interference with the virtual image and improving the viewing effect of the user.

[0092] Fourth, the optical path folding unit 130 includes an AR film, a quarter-wave plate, and a reflective polarizing film. The anti-reflection and anti-reflection enhancement film, the quarter-wave plate, and the reflective polarizing film are sequentially located on the optical path of the image light emitted by the image generation unit and are sequentially located on the optical path of the image light emitted by the imaging unit.

[0093] Compared with the second structure, the addition of the AR film is beneficial to reducing the stray light caused by interface reflection, further improving the display effect and enhancing the light efficiency.

[0094] Fifth, the optical path folding unit 130 includes an AR film, a quarter-wave plate, a reflective polarizing film, and an absorptive polarizing film. The anti-reflection and anti-reflection enhancement film, the quarter-wave plate, the reflective polarizing film, and the absorptive polarizing film are sequentially located on the optical path of the image light emitted by the image generation unit 110 and are sequentially located on the optical path of the image light emitted by the imaging unit 140.

[0095] Compared with the third structure, the addition of the AR film is beneficial to reducing the stray light caused by interface reflection, further improving the display effect and enhancing the light efficiency.

[0096] It should be noted that in the embodiments of the present application, the polarizing film may also be referred to as a polarizer or a polarizing sheet. The polarization directions of the reflective polarizing film and the absorptive polarizing film are the same, and both are the second polarization direction. In this way, the reflective polarizing film is used to reflect linearly polarized light in the first polarization direction and transmit linearly polarized light in the second polarization direction, and the absorptive polarizing film is used to absorb linearly polarized light in the first polarization direction and transmit linearly polarized light in the second polarization direction. Among them, the first polarization direction and the second polarization direction are perpendicular. Exemplarily, the linearly polarized light in the first polarization direction is S light, and the linearly polarized light in the second polarization direction is P light. Or, the linearly polarized light in the first polarization direction is P light, and the linearly polarized light in the second polarization direction is S light.

[0097] In addition, the imaging optical paths of the foregoing third to fifth structures are basically the same as the imaging optical path of the second structure (i.e., Figure 7 ), so the detailed description is omitted.

[0098] Optionally, the virtual image display device further includes a housing (not shown in the figure). The housing has an observation window opposite to the user's eyes for the user to view the virtual image. The image generation unit 110, the occlusion unit 120, the optical path folding unit 130, and the imaging unit 140 are all located inside the housing. In this way, the housing 140 can protect each unit and integrate each unit through the housing 140 to facilitate the overall movement of the virtual image display device.

[0099] The embodiments of the present disclosure do not limit the shape of the housing, which may be a cuboid or a cylinder, etc. In addition, when the virtual image display device is integrated into a certain large product, such as integrated into the seat of a vehicle, a receiving cavity can be provided by the seat, and the image generation unit 110, the occlusion unit 120, the optical path folding unit 130, and the imaging unit 140 can be directly arranged in the receiving cavity, so that the housing can be omitted.

[0100] In some examples, the imaging unit 120 includes an opaque reflective imaging element, such as a curved mirror (such as a curved mirror made of metal), etc. In other examples, the imaging unit 120 includes a light-transmitting reflective imaging element, such as a lens, a lens group composed of multiple lenses, or a light-transmitting curved mirror, etc. When the imaging unit 120 adopts an opaque reflective imaging element, the virtual image display device is a virtual reality (VR) display device, and when the imaging unit 120 adopts a light-transmitting reflective imaging element, the virtual image display device is an augmented reality (AR) display device.

[0101] The structures of each unit have been described above. Next, the Figure 5 arrangement of each unit will be described.

[0102] As shown Figure 5 in FIG. Figure 5 , the optical path folding unit 130 has a reflective surface for reflecting at least a part of the image light from the shielding unit 120 to the imaging unit 140. The included angle α between the reflective surface and the optical axis O 1 of the imaging unit 140 ranges from 55 to 75 degrees. The optical axis O 2 of the image generation unit 110 and the optical axis O 1 of the imaging unit 140 have an included angle β ranging from 55 to 75 degrees.

[0103] Through simulation experiments, it is found that when the reflective surface of the optical path folding unit 130, the optical axis O 1 of the imaging unit 140, and the optical axis O 2 of the image generation unit 110 satisfy the above angle relationship, the display performance of the virtual image display device is better. Here, the display performance includes distortion, binocular parallax, modulation transfer function (MTF), etc. However, when the reflective surface of the optical path folding unit 130, the optical axis O 1 of the imaging unit 140, and the optical axis O 2 of the image generation unit 110 satisfy the above angle relationship, the ghost image is relatively obvious. Therefore, it is particularly necessary to set a shielding unit in the virtual image display device.

[0104] Exemplarily, the included angle between the optical axis O 1 of the imaging unit 140 and the horizontal plane is 0 to 5 degrees. Figure 5 FIG. Figure 5 shows an example with the optical axis O1 parallel to the horizontal plane. Generally, the user's line of sight when viewing the virtual image is approximately parallel to the horizontal plane. Therefore, setting the included angle between the optical axis of the imaging unit and the horizontal plane to 0 to 5 degrees is convenient for the user to view.

[0105] When the included angle between the optical axis O 1 of the imaging unit 140 and the horizontal plane is 0 to 5 degrees, the included angle between the optical axis O 1 of the imaging unit 140 and the horizontal plane is 60 to 70 degrees (such as 65 degrees), and the included angle between the reflective surface of the optical path folding unit 130 and the vertical plane is 20 to 30 degrees (such as 25 degrees).

[0106] It should be noted that Figure 5 , Figure 6 and Figure 7 in FIG. Figure 7 , an example is shown with the image generation unit 110 located above the imaging unit 140, and both the image generation unit 110 and the imaging unit 140 are located on the right side (the side far from the user) of the optical path folding unit 130. In actual applications, the image generation unit 110 can also be arranged below the imaging unit 140, as shown Figure 8 in FIG. Figure 8 .

[0107] Optionally, the virtual image display device may further include a main processor. The main processor is configured to send image data to the image generation unit.

[0108] Optionally, the virtual image display device further includes a power supply for powering the main processor and the image generation unit.

[0109] In the embodiment of the present application, as Figure 5 shown, after the image light emitted by the image generation unit 110 passes through the occlusion unit 120, it reaches the optical path folding unit 130, and the optical path folding unit 130 guides the received image light to the imaging unit 140. The imaging unit 140 reflects the image light to the human eye, so that the user can view the virtual image S1.

[0110] When the virtual image display device does not include an occlusion unit, the stray light that is emitted by the image generation unit and does not participate in forming the virtual image is guided by the optical path folding unit to the imaging unit, and the stray light reflected by the imaging unit is then guided by the optical path folding unit to the imaging surface of the image generation unit. Then, the imaging surface of the image generation unit reflects the stray light to the optical path folding unit, and then successively passes through the optical path folding unit and the imaging unit and is reflected to the human eye.

[0111] In the embodiment of the present application, as Figure 6 shown, the stray light from the image generation unit 110 passes through the occlusion unit 120 and reaches the optical path folding unit 130. The optical path folding unit 130 guides the received stray light to the imaging unit 140. The imaging unit 140 reflects the stray light back to the optical path folding unit 130, and is then guided by the optical path folding unit 130 to the occlusion unit 120 and the image generation unit 110 again. The stray light reflected by the occlusion unit 120 and the image generation unit 110 reaches the optical path folding unit 130 again, and is then guided by the optical path folding unit 130 to the imaging unit 140, and is reflected by the imaging unit 140 to the human eye. If the stray light incident on the human eye is strong, the human eye will see a ghost image S2.

[0112] Assume that the transmittance of the optical path folding unit is T1, the reflectivity is R1; the reflectivity of the imaging unit is R2, and the reflectivity of the imaging surface of the image generation unit is R3, and the outgoing light brightness is Lv. Then, the brightness L1 of the virtual image formed by the virtual image display device and the brightness L2 of the ghost image can be calculated by formulas (1) and (2) respectively.

[0113] L1 = Lv * R1 * R2 * T1 (1)

[0114] L2 = Lv * R1 * R2 * R1 * R3 * R1 * R2 * T1 (2)

[0115] As can be seen from Formula (1) and Formula (2), the brightness of the virtual image is strongly correlated with R1, R2, and T1. Without affecting the light efficiency of the system, the brightness of the ghost image can be effectively reduced by reducing R3.

[0116] Therefore, in the embodiments of the present application, since the shielding unit prevents the stray light from the optical path folding unit from being emitted again towards the optical path shielding unit, the reflection ability of the surface of the shielding unit close to the optical path folding unit is lower than that of the imaging surface of the image generation unit, which is equivalent to reducing R3. Therefore, the intensity of the stray light incident on the human eye is significantly reduced, and the user will not see obvious ghost images, or even will not see ghost images, thereby improving the display effect of the virtual image display device.

[0117] Taking the image source as an LCD as an example, the SCI reflectivity of its imaging surface is generally about 6%. By reducing the SCI reflectivity to 1%, the brightness of the ghost image can be reduced to 16.7% of the original ghost image brightness (i.e., the ghost image brightness when the shielding unit is not set).

[0118] The embodiments of the present application further provide a vehicle, which includes any one of the foregoing virtual image display devices.

[0119] Please refer to Figure 9 , Figure 9 which is a functional schematic diagram of a vehicle provided by the embodiments of the present application.

[0120] The vehicle may include various subsystems, such as the sensor system 21, the control system 22, one or more peripheral devices 23 (illustrated by one in the figure), the power supply 24, the computer system 25, and the display system 26 shown in the figure. The above-mentioned subsystems can communicate with each other. The display system 22 may include the virtual image display device provided by the embodiments of the present application. The vehicle may also include other functional systems, such as an engine system, a cockpit, etc. that provide power for the vehicle, which are not limited herein.

[0121] Among them, the sensor system 21 may include several detection devices, which can sense the measured information and convert the sensed information into electrical signals or other required forms of information according to certain rules and output them. As Figure 9 shown, these detection devices may include a Global Positioning System (GPS), a vehicle speed sensor, an Inertial Measurement Unit (IMU), a radar unit, a laser rangefinder, a camera device, a wheel speed sensor, a steering sensor, a gear sensor, or other elements for automatic detection, etc., which are not limited in the present application.

[0122] The control system 22 may include several components, such as the illustrated steering unit, braking unit, lighting system, autonomous driving system, map navigation system, network time synchronization system, and obstacle avoidance system. The control system 22 can receive the information (such as vehicle speed, vehicle distance, etc.) sent by the sensor system 21 to implement functions such as autonomous driving and map navigation.

[0123] Optionally, the control system 14 may also include components such as a throttle controller and an engine controller for controlling the driving speed of the vehicle, which are not limited in this application.

[0124] The peripheral device 23 may include several components, such as a communication system, a touch screen, a user interface, a microphone, and a speaker, etc. Among them, the communication system is used to implement network communication between the vehicle and other devices except the vehicle. In practical applications, the communication system can use wireless communication technology or wired communication technology to implement network communication between the vehicle and other devices. The wired communication technology may refer to communication between the vehicle and other devices through a network cable or optical fiber, etc.

[0125] The power supply 24 represents a system that provides power or energy for the vehicle, which may include but is not limited to rechargeable lithium batteries or lead-acid batteries, etc. In practical applications, one or more battery components in the power supply are used to provide electrical energy or energy for vehicle startup, and the type and material of the power supply are not limited in this application.

[0126] Several functions of the vehicle can be controlled and implemented by the computer system 25. The computer system 25 may include one or more processors 2501 (illustrated with one processor as an example) and a memory 2502 (also referred to as a storage device). In practical applications, the memory 2502 may also be inside the computer system 25 or outside the computer system 25, such as a cache in the vehicle, which is not limited in this application.

[0127] Among them, the processor 2501 may include one or more general-purpose processors, such as a graphics processing unit (GPU). The processor 2501 can be used to run the relevant programs or the instructions corresponding to the programs stored in the memory 2502 to implement the corresponding functions of the vehicle.

[0128] The memory 2502 may include volatile memory, such as RAM; the memory may also include non-volatile memory, such as ROM, flash memory, HDD or solid state drive SSD; the memory 2502 may further include a combination of the above types of memory. The memory 2502 can be used to store a set of program codes or instructions corresponding to the program codes, so that the processor 2501 can call the program codes or instructions stored in the memory 2502 to implement the corresponding functions of the vehicle. In this application, a set of program codes for vehicle control can be stored in the memory 2502, and the processor 2501 can call the program codes to control the vehicle to drive safely. How to achieve safe driving of the vehicle will be described in detail below in this application.

[0129] Optionally, in addition to storing program codes or instructions, the memory 2502 can also store information such as road maps, driving routes, sensor data, etc. The computer system 25 can combine with other elements in the vehicle function framework schematic diagram, such as sensors in the sensor system, GPS, etc., to implement the relevant functions of the vehicle. For example, the computer system 25 can control the driving direction or driving speed of the vehicle based on the data input of the sensor system 21, which is not limited in this application.

[0130] The display system 26 can interact with other systems in the vehicle. For example, it can display the navigation information sent by the control system 22, or play the video sent by the computer system 25 and the peripheral device 23, etc. For the specific structure of the display system 26, refer to the embodiments of the virtual image display device above, which will not be elaborated here.

[0131] Among them, the four subsystems illustrated in this embodiment, the sensor system 21, the control system 22, the computer system 25 and the display system 26 are only examples and do not constitute limitations. In practical applications, the vehicle can combine several components in the vehicle according to different functions to obtain corresponding different functional subsystems. In practical applications, the vehicle may include more or fewer subsystems or components, which is not limited in this application.

[0132] The vehicle in the embodiments of this application can be known vehicles such as cars, airplanes, ships, rockets, etc., or new vehicles that will emerge in the future. The car can be an electric vehicle, a fuel vehicle or a hybrid vehicle. For example, a pure electric vehicle, an extended-range electric vehicle, a hybrid electric vehicle, a fuel cell vehicle, a new energy vehicle, etc., which is not specifically limited in this application.

[0133] Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meanings as understood by those of ordinary skill in the art to which this disclosure pertains. The terms "first", "second", "third" and similar terms used in the description and claims of this patent application of the disclosure do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, terms such as "a" or "an" do not denote a limitation of quantity, but mean that there is at least one. Terms such as "comprising" or "including" mean that the elements or items appearing before "comprising" or "including" cover the elements or items listed after "comprising" or "including" and their equivalents, and do not exclude other elements or items. "A and / or B" means any of the following three cases: A, B, and A and B.

[0134] The foregoing is only one embodiment of this application and is not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made on the basis of this application shall be included within the protection scope of this application.

Claims

1. A virtual image display device, characterized in that, the virtual image display device is a desktop display device or a vehicle-mounted display device, and the virtual image display device includes: an image generation unit, an occlusion unit, an optical path folding unit, and an imaging unit; the image generation unit is configured to emit image light; the occlusion unit is located on the optical path between the image generation unit and the optical path folding unit, and the occlusion unit is attached to the imaging surface of the image generation unit; the occlusion unit is configured to transmit at least part of the image light from the image generation unit to the optical path folding unit, and block at least part of the stray light from the optical path folding unit from being emitted to the optical path folding unit; the occlusion unit includes a stacked anti-reflection and anti-glare layer; the anti-reflection and anti-glare layer includes alternately stacked first sub-layers and second sub-layers, and the refractive indices of the first sub-layers and the second sub-layers are different; the internal haze of the anti-glare layer is greater than the external haze of the anti-glare layer, and the anti-glare layer has the function of anti-flash point; the SCI reflectance of the surface of the occlusion unit close to the optical path folding unit is less than or equal to 2%, and is less than the SCI reflectance of the imaging surface of the image generation unit; the optical path folding unit includes: a quarter-wave plate and a reflective polarizing film sequentially located on the optical path of the image light emitted by the image generation unit; the optical path folding unit is configured to direct the image light from the occlusion unit to the imaging unit; the imaging unit is configured to form a virtual image based on the image light from the optical path folding unit, and the quarter-wave plate and the reflective polarizing film are sequentially located on the optical path of the image light emitted by the imaging unit.

2. The virtual image display device according to claim 1, characterized in that, the optical path folding unit has a reflective surface, and the reflective surface is configured to reflect at least part of the image light from the occlusion unit to the imaging unit, and the included angle between the reflective surface and the optical axis of the imaging unit ranges from 55 to 75 degrees; the included angle between the optical axis of the image generation unit and the optical axis of the imaging unit ranges from 55 to 75 degrees.

3. The virtual image display device according to any one of claims 1 to 2, characterized in that, the included angle between the optical axis of the imaging unit and the horizontal plane is 0 to 5 degrees.

4. The virtual image display device according to any one of claims 1 to 3, characterized in that, the imaging unit includes a curved mirror or a lens.

5. The virtual image display device according to any one of claims 1 to 4, characterized in that, the image light emitted by the image generation unit is linearly polarized light, circularly polarized light or elliptically polarized light.

6. The virtual image display device according to any one of claims 1 to 5, characterized in that, the image generation unit includes a liquid crystal display, an organic light-emitting diode (OLED) display or a light-emitting diode (LED) display; alternatively, the image generation unit includes a light source and a reflective spatial light modulator, and the reflective spatial light modulator is configured to modulate and reflect the light beam generated by the light source to obtain the image light.

7. A vehicle, characterized in that, it includes the virtual image display device according to any one of claims 1-6, and the virtual image display device is installed on the vehicle.

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