Head-up display module and vehicle

Abstract

The embodiment of the invention discloses a head-up display module and a vehicle, and relates to the field of display. The objective of the invention is to improve the problem of HOE-HUD ghosting. According to the specific scheme, when image light is transmitted to a holographic optical element, the intensity ratio of light beams in a P polarization state in the image light is larger than 70%. Furthermore, the incident angle and the diffraction angle of the image light incident to the holographic optical element are close, and the incident angle is 45-65 degrees. The incident angle of the image light is close to the polarization angle, the reflection efficiency of the holographic optical element to the P light is low, and the diffraction efficiency of the holographic optical element to the P light is not changed. The holographic optical element is almost not reflected into human eyes, and diffracted light rays enter the human eyes, so that the problem of ghosting is effectively improved. When the incident angle is close to the diffraction angle, the problem of dispersion does not exist. The head-up display module is suitable for a light source with a wide line width, for example, the line width is smaller than 10 nm.

Description

Technical Field

[0001] This application relates to the field of displays, and more particularly to a head-up display module and a vehicle. Background Technology

[0002] Head-up display (HUD) technology, also known as head-up display, has been increasingly widely used in the automotive, aerospace, and marine industries in recent years. For example, in the automotive field, the image projection device in a HUD projects important information about the vehicle's movement onto the windshield. Reflected by the windshield, a virtual image is formed directly in front of the driver's line of sight, allowing the driver to see this information without looking down. Compared to instrument panels and center console screens, which require the driver to look down, HUDs avoid the driving risks that might arise from the driver's inability to see road conditions while looking down, making them a safer in-vehicle display method.

[0003] Augmented reality (AR) head-up displays (AR-HUDs), which have emerged in recent years, overlay digital images onto the real-world environment outside the vehicle, providing drivers with an augmented reality visual experience. This can be used for AR navigation, adaptive cruise control, lane departure warning, and more. To better integrate AR images with road information...

[0004] Holographic optical element (HOE) HUD (HOE-HUD) technology integrates a transparent HOE film onto the windshield. Based on the principle of diffraction, it can realize the function of a lens, providing optical power at the windshield position, which greatly reduces the overall system size. It is one of the technological directions of the next generation of AR-HUD.

[0005] Currently, HOE-HUD suffers from severe ghosting issues. Summary of the Invention

[0006] This application provides a head-up display module and a vehicle. The aim is to improve the ghosting problem in the head-up display module.

[0007] To achieve the above objectives, this application adopts the following technical solution.

[0008] In a first aspect, embodiments of this application provide a head-up display (HUD) module. The HUD module includes an image projection device and a holographic optical element. The image projection device emits image light. The holographic optical element receives the image light and diffracts it before emitting it. When the image light is transmitted to the holographic optical element, the intensity of the P-polarized state light beam in the image light accounts for >70% relative to the surface of the holographic optical element. Thus, when the image light is transmitted to the surface of the holographic optical element, the intensity of the P-polarized state light in the image light is greater than 70%, resulting in lower reflection efficiency of the holographic optical element and weaker reflected light. This reduces the intensity of light entering the human eye (e.g., the driver's eye) after being reflected by the holographic optical element. Furthermore, the light diffracted by the holographic optical element enters the human eye only, preventing both reflected and diffracted light from entering the eye simultaneously, effectively improving the problem of ghosting.

[0009] In conjunction with the first aspect, in some feasible methods, the incident angle of the image light onto the holographic optical element is θ1, and the diffraction angle of the holographic optical element is θ2, where the relationship -20°≤θ1-θ2≤20° is satisfied. Thus, the incident angle of the image light onto the holographic optical element is close to the diffraction angle of the holographic optical element. This effectively avoids the dispersion problem of the holographic optical element. Even if the spectral width of the image light source is wide, the holographic optical element is less prone to dispersion problems.

[0010] In conjunction with the first aspect, in some feasible methods, the relationship 45°≤θ1≤65° is satisfied. Because the intensity of the P-polarized state light accounts for a large proportion of the image light, the reflection efficiency of the holographic optical element is low when the image light is transmitted to its surface. This effectively solves the ghosting problem. Even with a large incident angle, the ghosting problem is mild or nonexistent. Furthermore, the incident angle of the image light onto the holographic optical element is also a factor affecting the dispersion problem of the holographic optical element. A larger incident angle can effectively reduce the dispersion problem of the holographic optical element. Therefore, the ghosting and dispersion problems of the head-up display module 100 provided in this application embodiment are effectively improved.

[0011] Combining the first aspect, in some feasible methods, the relationship 51°≤θ1≤61° is satisfied. When the angle of image light incident on the holographic optical element is 51°~61°, the Fresnel reflection efficiency of the P-polarized beam is less than 0.3%. It can be considered that there is almost no reflection, and almost no reflected light enters the human eye. The ghosting problem can be further optimized.

[0012] In conjunction with the first aspect, in some feasible embodiments, the image projection device includes a first light source, a first polarization structure, and a first image generator. The first light source emits unpolarized light. The first polarization structure receives the unpolarized light from the first light source and emits P-polarized light. The first image generator receives the P-polarized light and generates the image light. Thus, by changing the polarization state of the light emitted from the first light source through the first polarization structure, P-polarized light can be obtained. The first image generator receives the P-polarized light and generates the image light, in which the intensity of the P-polarized beam constitutes a large proportion.

[0013] In conjunction with the first aspect, in some feasible embodiments, the first polarization structure includes a P-polarized polarizer. Thus, the P-polarized polarizer allows a P-polarized light beam to pass through. Unpolarized light passing through the P-polarized polarizer yields P-polarized light.

[0014] In conjunction with the first aspect, in some implementable embodiments, the first polarization structure includes an S-polarization polarizer and a polarization converter. The first polarization structure for receiving unpolarized light from the first light source and emitting P-polarized light comprises: the S-polarization polarizer receiving the unpolarized light from the first light source and emitting S-polarized light, and the polarization converter converting the S-polarized light into P-polarized light. Thus, the first polarization structure can also convert unpolarized light into P-polarized light.

[0015] In conjunction with the first aspect, in some feasible implementations, the image projection device includes a second light source, a second image generator, and a second polarization structure. The second light source is used to emit unpolarized light. The second image generator is used to receive the unpolarized light from the second light source and generate unpolarized light carrying image information. The second polarization structure is used to receive the unpolarized light carrying image information from the second image generator and emit the image light in a P-polarized state. Thus, the image projection device can emit image light carrying image information with a high P-polarization state intensity (e.g., greater than 70%).

[0016] In conjunction with the first aspect, in some feasible embodiments, the image projection device includes a third light source and a third image generator. The third light source emits P-polarized light. The third image generator receives the P-polarized light from the third light source and generates the image light. Thus, by emitting P-polarized light from the third light source, the light emitted by the third light source can be fully utilized during the image light formation process, reducing the intensity loss of the emitted light, improving the energy utilization rate of the third light source, and increasing its efficiency.

[0017] In conjunction with the first aspect, in some feasible implementations, the head-up display module further includes a light shaping element. This light shaping element receives image light from the image projection device and shapes the image light before projecting it onto the holographic optical element. Thus, the light shaping element can shape the image light before projecting it onto the holographic optical element.

[0018] Secondly, embodiments of this application provide a means of transportation. The means of transportation includes a carrier element and any of the head-up display modules provided in the first aspect, the head-up display module being connected to the carrier element.

[0019] In conjunction with the second aspect, in some feasible implementations, the carrier element includes a windshield connected to the holographic optical element. Typically, the windshield 22 forms an angle of 25° to 35° with the horizontal plane. The windshield is connected to the holographic optical element, and the holographic optical element forms an angle of 25° to 35° with the horizontal plane. When the angle of incident light on the holographic optical element is 51° to 61°, the Fresnel reflection efficiency of the P-polarized beam is less than 0.3%. It can be considered that there is almost no reflection, and almost no reflected light enters the human eye. Furthermore, since the diffraction efficiency of the holographic optical element is independent of the polarization state of the incident light, the diffraction efficiency is almost unaffected after the image light with higher intensity in the P-polarized state is transmitted to the holographic optical element. This effectively improves the ghosting problem without affecting the normal operation of the holographic optical element.

[0020] In conjunction with the second aspect, in some feasible ways, the holographic optical element is connected to the inner or outer surface of the windshield. This facilitates the installation and removal of the holographic optical element and the windshield. For example, the holographic optical element can be connected to an already assembled vehicle.

[0021] In conjunction with the second aspect, in some feasible ways, the holographic optical element is housed within the windshield. Thus, the holographic optical element is integrated within the windshield, which can isolate it from moisture, dust, and other impurities, reducing the impact of these impurities on the holographic optical element and extending its lifespan. Attached Figure Description

[0022] Figure 1a This is a structural diagram of a vehicle.

[0023] Figure 1b This is a schematic diagram of the optical path structure of a head-up display module.

[0024] Figure 2a This is a schematic diagram of the structure of the head-up display module provided in an embodiment of this application.

[0025] Figure 2b This is a graph showing the polarization characteristics of Fresnel reflection.

[0026] Figure 3aThis is a schematic diagram of the structure of an image projection device provided in an embodiment of this application.

[0027] Figure 3b These are schematic diagrams of two structures of the first polarization structure provided in the embodiments of this application.

[0028] Figure 3c This is a schematic diagram of another image projection device provided in an embodiment of this application.

[0029] Figure 3d This is a schematic diagram of the structure of another image projection device provided in the embodiments of this application.

[0030] Figure 4 This is a schematic diagram of the structure of the windshield and holographic optical element provided in the embodiments of this application.

[0031] In the diagram: 20-Vehicle; 21-Bearing element; 22-Windshield; 10-Head-up display module; 100-Image projection device; 200-Holographic optical element; 110-First light source; 120-First polarization structure; 121-Polarizer in P-polarization state; 122-Polarizer in S-polarization state; 123-Polarization converter; 130-First image generator; 210-Second light source; 220-Second polarization structure; 230-Second image generator; 310-Third light source; 320-Third image generator; 102-Dustproof box; 103-Light-transmitting part; 101-Light shaping element. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0033] In the following description, 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 technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0034] Furthermore, in this application, directional terms such as "upper" and "lower" are defined relative to the orientation of the components shown in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the orientation of the components in the accompanying drawings.

[0035] This application provides a means of transportation. This means of transportation can include road vehicles, water vehicles, air vehicles, industrial equipment, agricultural equipment, or recreational equipment, etc. For example, a road vehicle can be a vehicle, which is a vehicle in a broad sense, including passenger vehicles (such as commercial vehicles, high-speed trains, passenger cars, motorcycles, flying cars, trains, etc.), industrial vehicles (such as forklifts, trailers, tractors, etc.), engineering vehicles (such as excavators, bulldozers, cranes, etc.), agricultural equipment (such as lawnmowers, harvesters, etc.), amusement equipment, toy vehicles, etc. This application does not specifically limit the type of vehicle. As another example, a means of transport can be an airplane or a ship. This application uses a passenger car as an example for description.

[0036] Figure 1a This is a structural schematic diagram of a vehicle 20. (Example) Figure 1a As shown, vehicle 20 includes a support element 21 and a head-up display module 10, which are connected to the support element 21. The support element 21 may include, for example, a windshield 22. The head-up display module 10 projects navigation information, instrument information, etc., into the driver's forward field of vision, preventing the driver from looking down to view this information and thus ensuring driving safety. The image projected by the head-up display module 10 is reflected by the windshield, forming a virtual image outside the vehicle.

[0037] Figure 1b This is a schematic diagram of the optical path structure of a head-up display module 10. Please refer to [link / reference]. Figure 1b The windshield 22 is translucent, allowing the driver to receive light passing through it, as well as light emitted from the head-up display module 10. For example, the driver can see the situation in front of the vehicle while also viewing the image light emitted from the head-up display module 10.

[0038] Figure 2a This is a schematic diagram of the structure of the head-up display module 10 provided in an embodiment of this application. Please refer to... Figure 2a The head-up display module 10 includes an image projection device 100 and a holographic optical element (HOE) 200. The image projection device 100 emits image light. The holographic optical element 200 receives the image light from the image projection device 100, diffracts the image light, and then emits it.

[0039] Specifically, when image light is transmitted to the holographic optical element 200, the intensity of the P (parallel) polarized beam in the image light accounts for >70% relative to the surface of the holographic optical element 200. In other words, the ratio of the intensity of light with P polarization to the intensity of image light is greater than 70%. A P polarized beam refers to a beam whose polarization direction is parallel to the incident plane, which is the surface of the holographic optical element 200.

[0040] When image light is transmitted to the surface of the holographic optical element 200, the intensity of the P-polarized state light accounts for more than 70% of the image light. The holographic optical element 200 has low reflection efficiency for the image light, resulting in weaker reflected light. This reduces the intensity of light entering the human eye (e.g., a driver's eye) after being reflected by the holographic optical element 200. Furthermore, by preventing both reflected and diffracted light from entering the eye, the problem of ghosting is effectively improved.

[0041] For example, the intensity percentage of the beam in the P (German: Parallel) polarization state in the image light can be 70%, 80%, 85%, 90%, 95%, 98%, or 100%, etc.

[0042] It is understood that, in addition to P-polarized beams, image light may also include S-polarized beams. The intensity of S-polarized beams is ≤30%. For example, the intensity of S-polarized beams can be 30%, 20%, 15%, 8%, 5%, 3%, or 0. S-polarized beams refer to beams whose polarization direction is perpendicular to the plane of incidence.

[0043] Furthermore, in some embodiments of this application, the incident angle of the image light onto the holographic optical element 200 is θ1, and the diffraction angle of the holographic optical element 200 is θ2, wherein the relationship -20°≤θ1-θ2≤20° is satisfied. Thus, the incident angle of the image light onto the holographic optical element 200 is close to the diffraction angle of the holographic optical element 200. This effectively avoids the dispersion problem of the holographic optical element 200. Even if the spectral width of the image light source is wide, the holographic optical element 200 is less prone to dispersion problems. For example, the spectral width of the image light source can be less than 10 nm (nanometers).

[0044] For example, θ1 is the angle between the principal ray of the image light and the normal to the surface of the holographic optical element 200. The diffraction angle is also called the angle of deviation, and θ2 is the angle between the image light and the normal when the image light diffracts.

[0045] For example, the values ​​of θ1-θ2 can be ±20°, ±18°, ±17°, ±15°, ±13°, ±10°, ±9°, ±8°, ±7°, ±6°, 5±°, ±4°, ±3°, ±2°, ±1°, or 0°, etc.

[0046] In some embodiments of this application, the incident angle θ1 of the image light onto the holographic optical element 200 is relatively large. For example, 45°≤θ1≤65°. Exemplarily, the incident angle θ1 of the image light onto the holographic optical element 200 can be 45°, 46°, 48°, 50°, 52°, 54°, 55°, 60°, 62°, 64°, or 65°, etc.

[0047] Figure 2b This is a graph showing the polarization characteristics of Fresnel reflection. Figure 2b In the figure, curve n1 is the relationship between the incident angle and the reflection efficiency of the beam in the S polarization state, and curve n2 is the relationship between the incident angle and the diffraction efficiency of the beam in the P polarization state. Figure 2b As can be seen, within the incident angle θ1 range of 45° to 65°, the beam of polarization P has a higher diffraction efficiency and a lower reflection efficiency.

[0048] Because the intensity of the P-polarized state light accounts for a large proportion of the image light, the reflection efficiency of the holographic optical element 200 is low when the image light is transmitted to the surface of the holographic optical element 200. This effectively solves the ghosting problem. Even with a large incident angle θ1, the ghosting problem is mild or non-existent. Furthermore, the incident angle of the image light onto the holographic optical element 200 is also a factor affecting the dispersion problem of the holographic optical element 200. A larger incident angle θ1 can effectively reduce the dispersion problem of the holographic optical element 200. Therefore, the ghosting and dispersion problems of the head-up display module 10 provided in this embodiment are effectively improved. No other means are needed to solve the ghosting or dispersion problems. For example, it is not necessary to use a narrow linewidth light source to improve the dispersion problem. It is also not necessary to use two holographic optical elements to improve the dispersion problem. The head-up display module 10 provided in this embodiment is suitable for light sources with a relatively wide linewidth, such as a linewidth less than 10 nm. The head-up display module 100 provided in this application embodiment can use only one holographic optical element 200, making the head-up display module 10 smaller in size.

[0049] Thus, the incident angle of the image light onto the holographic optical element 200 is 60°, which is close to the Brewster angle, also known as the polarization angle. When the refractive index of the medium of the holographic optical element 200 is 1.5, the Brewster angle is approximately 56°.

[0050] P-polarized beams are characterized by low reflection efficiency at Brewster angles. For example, when the angle of incident light is 51° to 61°, the Fresnel reflection efficiency of a P-polarized beam is less than 0.3%.

[0051] Please return Figure 2a In an embodiment where the holographic optical element 200 and the windshield 22 are connected, the angle between the windshield 22 and the horizontal plane is, for example, 25° to 35°. For instance, the angle between the windshield 22 and the horizontal plane is 25°, 28°, 30°, 32°, 33°, 35°, etc. Thus, the optical axis of the beam diffracted by the holographic optical element 200 has a small angle with or is parallel to the horizontal plane, allowing the driver to receive the image light by looking straight ahead, at a small angle upwards, or downwards.

[0052] After the holographic optical element 200 and the windshield 22 are connected, the P-polarized light beam transmitted to the holographic optical element 200 has a low reflection efficiency. Since the diffraction efficiency of the holographic optical element 200 is independent of the polarization state of the incident light, the image light with higher intensity in the P-polarized state, after being transmitted to the holographic optical element 200, has low reflection efficiency, and the diffraction efficiency is almost unaffected. Therefore, the light reflected by the holographic optical element 200 hardly enters the human eye, while the light diffracted by the holographic optical element 200 enters the human eye and is received, effectively improving the ghosting problem without affecting the normal operation of the holographic optical element 200.

[0053] The image projection device 100 provided in this application embodiment has reduced requirements for the spectral width of the image light source. For example, if the incident angle θ1 and diffraction angle θ2 of the image light incident on the holographic optical element 200 are equal, the spectral width of the image light source only needs to be less than or equal to 10 nm. If the difference between the incident angle θ1 and diffraction angle θ2 of the image light incident on the holographic optical element 200 is less than or equal to 10°, the spectral width of the image light source only needs to be less than or equal to 2 nm. This requirement is far lower than the prior art spectral width of less than 0.4 nm. The image projection device 100 provided in this application embodiment has a wider selection of image light sources, reducing the need for narrow-spectrum light sources in the image projection device 100.

[0054] This application does not limit the resolution of the image light in its embodiments. For example, the angular resolution of the image light can be 60 PPD (Pixels Per Degree).

[0055] In the embodiments of this application, the image projection device 100 has various structures, which are described below. Figure 3a , Figure 3b , Figure 3c as well as Figure 3d An example is provided.

[0056] Figure 3a This is a schematic diagram of the structure of an image projection device 100 provided in an embodiment of this application. Please refer to... Figure 3a The image projection device 100 includes a first light source 110, a first polarization structure 120, and a first image generator 130.

[0057] The first light source 110 emits unpolarized light, and the first polarization structure 120 receives the unpolarized light from the first light source 110 and emits P-polarized light. The first image generator 130 receives the P-polarized light and generates the image light.

[0058] Thus, by changing the polarization state of the light emitted from the first light source 110 through the first polarization structure 120, P-polarized light can be obtained. The first image generator 130 receives the P-polarized light and generates the image light, in which the intensity of the P-polarized beam accounts for a large proportion.

[0059] For example, the first image generator 130 may include a liquid crystal on silicon (LCOS) display, an organic light-emitting diode (OLED) display, a liquid crystal display (LCD), a digital light processing (DLP) display, or a micro-electro-mechanical system (MEMS) display, etc.

[0060] For example, the first light source 110 may include a laser light source, an organic light-emitting diode, and an incandescent lamp, etc.

[0061] This application does not limit the connection method between the first light source 110 and the first polarization structure 120. For example, the first light source 110 and the first polarization structure 120 can be bonded together with optical adhesive. In some embodiments, the first light source 110 and the first polarization structure 120 can be set independently.

[0062] This application does not limit the connection method between the first image generator 130 and the first polarization structure 120. For example, the first image generator 130 and the first polarization structure 120 can be set independently, or the first image generator 130 and the first polarization structure 120 can be connected by transparent adhesive or the like.

[0063] One of the functions of the first polarization structure 120 is to convert unpolarized light into P-polarized light. Various structures can achieve this function.

[0064] Figure 3b Two schematic diagrams of the first polarization structure 120 provided in the embodiments of this application. Figure 3b In Figure (1), the first polarization structure 120 includes a P-polarized polarizer 121. The P-polarized polarizer allows P-polarized light beams to pass through. Unpolarized light passing through the P-polarized polarizer 121 can be converted into P-polarized light.

[0065] Figure 3b In Figure (2), the first polarization structure 120 includes a polarizer 122 in an S-polarization state and a polarization converter 123. The aforementioned first polarization structure 120 is used to receive signals from the first light source 110 (e.g., ...). Figure 3a The method for transmitting unpolarized light (as shown) and emitting P-polarized light includes: an S-polarized polarizer 122 for receiving unpolarized light from the first light source 110 and emitting S-polarized light; and a polarization converter 123 for converting the S-polarized light into P-polarized light. Thus, the first polarization structure 120 can also convert unpolarized light into P-polarized light.

[0066] The aforementioned polarization converter 123 can deflect the polarization direction of polarized light. For example, it can deflect the polarization direction of polarized light by 90°. This application embodiment does not limit the structure of the polarization converter 123. In some embodiments, the polarization converter 123 includes a half-wave plate. The half-wave plate deflects the polarization direction of S-polarized light by 90°, outputting P-polarized light. In some embodiments, the polarization converter 123 includes two quarter-wave plates, which deflect the polarization direction of S-polarized light by 90°, outputting P-polarized light. In some embodiments, the polarization converter 123 is a twisted nematic (TN) liquid crystal layer. The twisted nematic liquid crystal layer can deflect the polarization direction of polarized light, converting S-polarized light into P-polarized light.

[0067] This application does not limit the connection method of the S-polarization polarizer 122 and the polarization converter 123. Exemplarily, the S-polarization polarizer 122 and the polarization converter 123 are connected by optical adhesive, making their relative positions relatively fixed and facilitating assembly. In some embodiments, the S-polarization polarizer 122 and the polarization converter 123 can be independently disposed in the optical path.

[0068] In some embodiments of this application, the image projection device 100 may further include other optical elements for adjusting the shape or propagation direction of light. For example, an optical element may be present between the first light source 110 and the first polarization structure 120 for changing the shape or propagation direction of unpolarized light. An optical element may be present between the first polarization structure 120 and the first image generator 130 for changing the shape or propagation direction of P-polarized light. Exemplarily, the aforementioned optical elements may be optical devices such as mirrors or focusing lenses.

[0069] Please return Figure 1b In some embodiments of this application, the head-up display module 10 may further include a dustproof box 102, within which the first light source 110, the first polarization structure 120, and the first image generator 130 are all located. The dustproof box 102 has a light-transmitting portion 103 through which image light can pass. The dustproof box 102 can block dust or moisture, preventing dust or moisture from contaminating the image projection device 100. For example, the aforementioned light-transmitting portion 103 can be made of transparent resin or glass.

[0070] Figure 3c A schematic diagram of another image projection device 100 provided in an embodiment of this application. Please refer to... Figure 3c The image projection device 100 includes a second light source 210, a second polarization structure 220, and a second image generator 230. The second light source 210 emits unpolarized light, and the second image generator 230 receives the unpolarized light from the second light source 210 and generates unpolarized light carrying image information. The second polarization structure 220 receives the unpolarized light carrying image information from the second image generator 230 and emits P-polarized image light.

[0071] Thus, the image projection device 100 can emit image light carrying image information and having a high P-polarization state intensity (e.g., greater than 70%).

[0072] Figure 3c and Figure 3a The differences include variations in polarization structure and the position of the image generator. For the second light source 210, please refer to the description of the first light source 110 above. For the second polarization structure 220, please refer to the description of the first polarization structure 120 above. For the second image generator 230, please refer to the description of the first image generator 130 above. Further details will not be provided here.

[0073] Figure 3d This is a schematic diagram of the structure of another image projection device 100 provided in an embodiment of this application. Please refer to... Figure 3dThe image projection device 100 includes a third light source 310 and a third image generator 320. The third light source 310 emits P-polarized light, and the third image generator 320 receives the P-polarized light from the third light source 310 and generates image light. Thus, by emitting P-polarized light from the third light source 310, the light emitted by the third light source 310 can be fully utilized during the image light formation process, reducing light intensity loss, improving energy utilization, and increasing the efficiency of the third light source 310.

[0074] The third light source 310 is used to emit P-polarized light. For example, the third light source 310 is a laser light source that emits P-polarized light.

[0075] Understandably, in some embodiments, the third light source 310 is used to emit S-polarized light, and the image projection device 100 may further include a transducer that converts the S-polarized light from the third light source 310 into P-polarized light. Similarly, image light with higher P-polarized beam intensity can also be obtained.

[0076] Please return Figure 1b In some embodiments of this application, the head-up display module 10 may further include a light shaping element 101, depending on the optical path requirements. The light shaping element 101 is used to receive image light from the image projection device 100, shape the image light, and project it onto the holographic optical element 200. The light shaping element 101 can be configured according to the requirements of the image light. In addition, the light shaping element 101 can also be configured according to the optical path design.

[0077] For example, the light shaping element 101 may include a reflective element for changing the propagation direction of the image light, thereby changing the transmission path of the image light. Thus, the image projection device 100 and the holographic optical element 200 can have various positional relationships. For example, the aforementioned reflective element may be a mirror or a reflective film.

[0078] In some embodiments, the light shaping element 101 may include collimating elements, focusing elements, etc., and may be configured according to the optical path requirements of the image light.

[0079] For example, the image projection device 100 can be installed inside the dashboard of a car. Alternatively, the image projection device 100 can be installed in other locations such as the roof of the car.

[0080] In the embodiments of this application, the windshield 22 and the holographic optical element 200 have multiple connection methods. The following describes... Figure 4 An exemplary description is provided.

[0081] Figure 4 This is a schematic diagram of the structure of the windshield 22 and the holographic optical element 200 provided in the embodiments of this application. Figure 4 In Figure (1), the holographic optical element 200 and the inner surface A of the windshield 22 are connected. The aforementioned "inner surface A of the windshield 22" refers to the surface of the windshield 22 facing the interior of the vehicle (e.g., a vehicle). This reduces the contact between dust, moisture, and other impurities and the holographic optical element 200, thus minimizing contamination of the holographic optical element 200. Furthermore, the connection between the inner surface A of the holographic optical element 200 and the windshield 22 facilitates the installation and removal of both. For example, the holographic optical element 200 can be connected to an already assembled vehicle.

[0082] This application embodiment does not limit the connection method of the inner surface A of the holographic optical element 200 and the windshield 22. For example, the inner surface A of the holographic optical element 200 and the windshield 22 can be connected by an adhesive layer, a solder layer or a snap fastener.

[0083] Figure 4 In Figure (2), the holographic optical element 200 and the outer surface B of the windshield 22 are connected. The aforementioned "outer surface B of the windshield 22" refers to the surface of the windshield 22 that faces away from the interior of the vehicle. This facilitates the disassembly and connection of the holographic optical element 200 and the windshield 22.

[0084] Figure 4 In Figure (3), the holographic optical element 200 is disposed inside the windshield 22. In other words, the holographic optical element 200 is disposed between the inner surface A and the outer surface B of the windshield 22. The probability of dust, water vapor and other impurities outside the windshield 22 coming into contact with the holographic optical element 200 is small, which can protect the holographic optical element 200 and improve its service life.

[0085] The head-up display module 10 provided in this embodiment includes a holographic optical element 200. In other embodiments, the head-up display module 10 may include two, three or more holographic optical elements 200, and this embodiment does not limit this.

[0086] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A head-up display module, characterized in that, The head-up display module includes: Image projection device, used to emit image light; Holographic optical element; used to receive the image light and diffract the image light before emitting it; Specifically, when the image light is transmitted to the holographic optical element, the intensity of the P-polarized beam in the image light accounts for >70% relative to the surface of the holographic optical element.

2. The head-up display module according to claim 1, characterized in that, The incident angle of the image light onto the holographic optical element is θ1, and the diffraction angle of the holographic optical element is θ2, wherein the following relationship is satisfied: -20°≤θ1-θ2≤20°.

3. The head-up display module according to claim 2, characterized in that, The following relationship is satisfied: 45°≤θ1≤65°.

4. The head-up display module according to any one of claims 1-3, characterized in that, The image projection device includes a first light source, a first polarization structure, and a first image generator; The first light source is used to emit unpolarized light; The first polarization structure is used to receive unpolarized light from the first light source and emit polarized light in the P-polarization state; The first image generator is used to receive the polarized light of the P polarization state and generate the image light.

5. The head-up display module according to claim 4, characterized in that, The first polarization structure includes a polarizer in the P-polarization state.

6. The head-up display module according to claim 4, characterized in that, The first polarization structure includes an S-polarization polarizer and a polarization converter; The first polarization structure for receiving unpolarized light from the first light source and emitting P-polarized light includes: The S-polarization polarizer is used to receive unpolarized light from the first light source and emit S-polarization polarized light, and the polarization converter is used to convert the S-polarization polarized light into P-polarization polarized light.

7. The head-up display module according to any one of claims 1-3, characterized in that, The image projection device includes a second light source, a second image generator, and a second polarization structure; The second light source is used to emit unpolarized light; The second image generator is used to receive unpolarized light from the second light source and generate unpolarized light carrying image information; The second polarization structure is used to receive unpolarized light carrying image information from the second image generator and emit the image light in the P-polarization state.

8. The head-up display module according to any one of claims 1-3, characterized in that, The image projection device includes a third light source and a third image generator; The third light source is used to emit P-polarized light; the third image generator is used to receive the P-polarized light from the third light source and generate the image light.

9. The head-up display module according to any one of claims 1-8, characterized in that, The head-up display module further includes a light shaping element, which is used to receive image light from the image projection device, shape the image light, and project it onto the holographic optical element.

10. A means of transportation, characterized in that, The vehicle includes: a load-bearing element and a head-up display module as described in any one of claims 1-9, wherein the head-up display module is connected to the load-bearing element.

11. The means of transport according to claim 10, characterized in that, The supporting element includes a windshield, which is connected to the holographic optical element.

12. The means of transport according to claim 11, characterized in that, The holographic optical element is connected to the inner or outer surface of the windshield.

13. The means of transport according to claim 11, characterized in that, The holographic optical element is disposed inside the windshield.

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