Head-up display device, vehicle and stray light suppression method of head-up display device

Abstract

The embodiment of the invention provides head-up display equipment, a vehicle and a stray light suppression method of the head-up display equipment. The head-up display device comprises an image generation unit, a diffusion assembly, a reflector group, a light-transmitting dustproof cover and a windshield which are sequentially arranged along a projection light path, the image generation unit is used for outputting projection light; the diffusion assembly comprises a base body, the base body comprises a surface A facing the image generation unit and a surface B back to the image generation unit, the surface A is provided with a microstructure array, and the surface B is provided with a phase retarder; wherein the surface A is configured to be capable of transmitting projection light in a first light path, and the surface A is configured to be capable of reflecting ambient light from the outside to the surface B and guiding the ambient light from the outside to the diffusion assembly in a second light path; the reflector group can be used for reflecting and amplifying projection light from the diffusion assembly; and a polarization element is arranged on the surface of the light-transmitting dust cover.

Description

Technical Field

[0001] This application relates to the field of optical display technology, and more specifically, to a head-up display device and vehicle, and a method for suppressing stray light from the head-up display device. Background Technology

[0002] As an important automotive electronic component, the head-up display (HUD) projects vehicle instrument information onto the windshield, helping drivers obtain key information without taking their eyes off the road, thereby improving driving safety.

[0003] Traditional HUD systems acquire projected images by illuminating the image generation unit (PGU) and then reflect the image onto the windshield using an internal amplification optical path to form a virtual image. However, traditional DLP-based PGU optical structures suffer from two major problems under sunlight: Sunlight temperature overload: Due to the reversibility of light, the internal amplified light path will converge sunlight to the diffuser, forming a high-energy converged light spot, which will damage the diffuser.

[0004] White frame effect: When sunlight shines directly onto the diffuser through the windshield, its diffuse reflection effect causes some light to be reflected back to the viewing point, forming stray light, reducing display contrast and producing a white frame effect, which affects the HUD user experience. Summary of the Invention

[0005] The purpose of this application is to provide a new technical solution for a head-up display device and vehicle, and a method for suppressing stray light from the head-up display device.

[0006] In a first aspect, this application provides a head-up display device, the head-up display device comprising the following components arranged sequentially along the projection light path: The image generation unit is used to output the projected light rays; A diffusion component includes a substrate, the substrate having an A-side facing the image generation unit and a B-side facing away from the image generation unit, the A-side being provided with a microstructure array, and the B-side being provided with a phase delayer; wherein, the A-side is configured in a first optical path to transmit projected light, and the A-side is configured in a second optical path to reflect ambient light from the outside to the B-side. The reflector assembly is used to reflect and amplify the projected light from the diffusion assembly, as well as to guide external ambient light to the diffusion assembly; A light-transmitting dust cover with polarizing elements on its surface.

[0007] Optionally, the head-up display device further includes a windshield. In the second optical path, external ambient light is filtered sequentially by the polarization element on the windshield and the light-transmitting dust cover to form a first linearly polarized light. The first linearly polarized light is reflected by the mirror group and incident on the B-side. After passing through the phase delayer on the B-side for the first time, the first linearly polarized light is converted into circularly polarized light. After propagating through the substrate and being reflected by the A-side, it passes through the phase delayer on the B-side for the second time and is converted into a second linearly polarized light. The second linearly polarized light is reflected back to the light-transmitting dust cover by the mirror group and is intercepted by the polarization element.

[0008] Optionally, in the first optical path, the projected light output by the image generation unit is natural light, which is deflected and diffused by the microstructure array on surface A and then projected onto surface B.

[0009] Optionally, the polarizing element disposed on the surface of the light-transmitting dust cover is a reflective polarizing film layer, which is configured as follows: Allowing light of the first linearly polarized state to pass through; and It can intercept second-linearly polarized light to prevent the second-linearly polarized light from entering the windshield area.

[0010] Optionally, the phase delayer is a quarter-wave plate, which can achieve a 90° phase delay of the light polarization state.

[0011] Optionally, the substrate is a glass plate, and the thickness of the substrate is 0.3mm to 1mm.

[0012] Optionally, the microstructure array is formed on surface A by nanoimprint lithography, and the microstructure array is used to deflect and diffuse the projected light output by the image generation unit.

[0013] Optionally, the image generation unit is a DLP PGU or an LCOS PGU.

[0014] Optionally, the reflector assembly includes components sequentially disposed between the diffusion assembly and the light-transmitting dust cover: Reflective folding mirrors are used to reflect and adjust the light path; and, Curved mirrors are used for secondary reflection and amplification of light.

[0015] Secondly, this application provides a method for suppressing stray light in a head-up display device, comprising: The ambient light is filtered by the polarizing element on the light-transmitting dust cover to obtain the first linearly polarized light. The first linearly polarized light is guided to the diffusion component, so that the first linearly polarized light can pass through the phase delayer disposed on the B surface of the diffusion component twice, thereby converting the first linearly polarized light into a second linearly polarized light; wherein, the A surface of the diffusion component is configured in the optical path to reflect ambient light from the outside to the B surface; The second linearly polarized light is guided back to the light-transmitting dust cover, and the polarization element is used to intercept the second linearly polarized light, so that the second linearly polarized light will not enter the windshield area, thereby eliminating stray light interference.

[0016] Thirdly, this application provides a vehicle, the vehicle comprising: The head-up display device as described in the first aspect.

[0017] The beneficial effects of this application are as follows: The head-up display device provided in this application embodiment, through a newly designed diffusion component, sets a microstructure array on its A side and a position delay device on its B side, and cooperates with a light-transmitting dust cover with polarizing elements on its surface, to achieve precise control of the projection light path (i.e., the first light path, or the forward light path) formed by normal projection light and the stray light path (i.e., the second light path, or the reverse light path) formed by external ambient light (such as sunlight). During the projection imaging process, the projected light output by the image generation unit is processed by the diffusion component, the reflector group, and the light-transmitting dust cover in sequence. Only the first linearly polarized light (such as S-polarized light) passes through the dust cover to form an image, ensuring high contrast of the projected image. In the case of sunlight backflow (i.e., the second light path, or the reverse light path), the diffusion component converts the incident first linearly polarized light into the second linearly polarized light (for example, from S-polarized light to P-polarized light). This second linearly polarized light is completely blocked by the polarization element on the dust cover, fundamentally eliminating the risk of temperature overload and white frame effect caused by sunlight convergence in traditional HUD systems, and greatly improving the reliability and driving safety of HUD devices in strong light environments.

[0018] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0020] Figure 1 A schematic diagram of the sunlight backflow optical path in a traditional HUD system; Figure 2 This is a schematic diagram of the projection optical path of a traditional HUD system; Figure 3 This is a schematic diagram of the structure of the head-up display device provided in the embodiments of this application; Figure 4 A schematic diagram of the projection optical path (projection optical path) of the head-up display device provided in the embodiments of this application. Figure 5 A schematic diagram of the backlight path (reverse light path) of the head-up display device provided in the embodiments of this application. Figure 6 A brightness loss curve of S-polarized light and P-polarized light of the head-up display device provided in the embodiments of this application.

[0021] Explanation of reference numerals in the attached figures: 1. Image generation unit; 2. Diffusion component; 21. Substrate; 22. A-plane; 221. Microstructure array; 23. B-plane; 24. Phase retarder; 2'. Diffuser (diffuser element used in traditional HUD systems); 3. Reflective folding mirror; 4. Curved reflective mirror; 5. Light-transmitting dust cover; 6. Windshield; 7. Polarizing element. Detailed Implementation

[0022] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0023] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0024] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0025] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0027] The following description, in conjunction with the accompanying drawings, details a head-up display device and vehicle, and a stray light suppression method for the head-up display device provided in this application.

[0028] According to one embodiment of this application, a head-up display device is provided, see [link to relevant documentation]. Figure 3 As shown, the head-up display device includes, sequentially arranged along the optical path, an image generating unit 1, a diffusion assembly 2, a reflector group, and a light-transmitting dust cover 5. The image generating unit 1 is used to output projected light. The diffusion assembly 2 includes a substrate 21, which has an A-side 22 facing the image generating unit 1 and a B-side 23 facing away from the image generating unit 1. The A-side 22 is provided with a microstructure array 221, and the B-side 23 is provided with a phase delay unit 24. The A-side 22 is configured in the first optical path to transmit projected light, and in the second optical path to reflect ambient light from the outside to the B-side 23. The reflector group is used to reflect and amplify the projected light from the diffusion assembly 2, and to guide ambient light from the outside to the diffusion assembly. The surface of the light-transmitting dust cover 5 is provided with a polarizing element 7.

[0029] The head-up display (HUD) provided in this application is specifically designed to address the core problems of traditional vehicle-mounted HUDs, such as damage to the diffuser caused by backflow of sunlight, reduced contrast due to stray light, and white frame effect. Through innovative optical structure design and integration of polarization light control technology, it achieves precise control of the projection light path and the sunlight stray light path, significantly improving the display stability and safety of the head-up display under complex lighting conditions.

[0030] The head-up display (HUD) provided in this application embodiment is designed for automotive environments. While ensuring high brightness and high contrast virtual image display, it effectively solves the risk of temperature overload caused by sunlight convergence in traditional solutions through innovative optical structure design and optimized thermal management strategies, and significantly reduces the interference of stray light on image quality. This HUD is particularly suitable for space-constrained vehicle installation environments, significantly extending the lifespan of optical components while reducing overall system power consumption.

[0031] The main components of the head-up display device provided in the embodiments of this application are described below.

[0032] The head-up display device provided in this application embodiment includes an image generation unit 1, see [link to application]. Figure 3 The image generation unit 1 serves as the light source starting point for the head-up display device and is used to output projected light.

[0033] It should be noted that the projected light output by the image generation unit 1 in this application is natural light.

[0034] The image generation unit 1 involved in this application employs DLP projection technology based on a digital micromirror device (DMD). It uses LEDs or UHP lamps as illumination sources. The light emitted by such light sources is optically defined as natural light, characterized by containing electric field vectors in all vibration directions, and with no fixed phase relationship between the various vibration components.

[0035] This is because the core component of the DLP optical engine, the DMD chip, is a metal micromirror array, and its reflection process itself does not change the polarization characteristics of the incident light. Therefore, when an unpolarized light source is used, the projected light output by the image generation unit 1 is natural light.

[0036] This characteristic is one of the important foundations of the solution in this application. In a forward projection optical path, see... Figure 3 and Figure 4 When the natural light passes through the phase delayer 24 on the B-side 23 of the diffusion component 2, the phase delayer 24 will not produce an effective phase modulation effect on it due to its irregular polarization state.

[0037] It should be noted that, in this application, the first optical path refers to the forward optical path, that is, the optical path traversed by the projected light emitted from the image generation unit 1. The second optical path refers to the reverse optical path, that is, the optical path traversed by the ambient light when sunlight shines back.

[0038] The head-up display device provided in this application embodiment includes a diffusion component 2. This diffusion component 2 differs significantly from the diffusion sheet 2' used in traditional HUD systems in terms of structural design and function. For traditional HUD systems, please refer to [link to traditional HUD system documentation]. Figure 1 and Figure 2 .

[0039] Specifically, see Figure 1 and Figure 2 The diffuser 2' used in traditional HUD systems only has basic diffuse reflection functionality; its core function is merely to deflect and amplify incident light. For example, see... Figure 1 When ambient light (such as sunlight) flows back into the HUD system through the windshield 6, the diffuser 2' inside the HUD system cannot effectively suppress stray light. This causes some ambient light to re-enter the projection light path after diffuse reflection, forming a white frame effect that interferes with the virtual image.

[0040] In contrast, the diffusion component 2 designed in this application achieves a functional breakthrough through a special double-sided composite optical design.

[0041] The diffusion component 2 provided in this application, see [link to application]. Figure 3 and Figure 5From a structural design perspective, it includes a substrate 21, which includes an A-side 22 near the image generation unit 1 and a B-side 23 near the mirror group; wherein, the A-side 22 provides support for the microstructure array 221, and the B-side 23 provides support for the phase delayer 24.

[0042] The diffusion component 2 of this application has a microstructure array 221 integrated on its A-side 22. The microstructure array 221 can not only deflect and diffuse light, but also control the angle of light propagation.

[0043] It should be noted that the A-side 22 of the substrate 21 of the diffusion component 2 in this application can transmit, reflect, and absorb some light, which is related to the optical material used to fabricate the substrate 21 (e.g., the transmittance and reflectivity of the optical material). However, the function used in this application is that, in the forward optical path, the A-side 22 can transmit projected light to facilitate subsequent projection imaging. In the reverse optical path, the A-side 22 can reflect light, mainly circularly polarized light, thereby avoiding stray light caused by sunlight backflow. It should also be emphasized that the A-side can transmit and reflect any light; this application mainly emphasizes the light that needs to be processed.

[0044] If the transmittance and reflectance of surface A 22 are to be adjusted, an optical film material such as an anti-reflection film can be provided on surface A, and this application does not impose any restrictions on this.

[0045] Another design feature of the diffusion component 2 in this application is the polarization state conversion function achieved by the phase delayer 24 integrated on the B-side 23. This component is capable of precisely phase modulating the incident linearly polarized light—that is, the first linearly polarized light (e.g., S-polarized light) formed after ambient light is filtered by the polarization element 7 on the surface of the transparent dust cover 5.

[0046] Specifically, in the second optical path (reverse optical path) for suppressing stray light, see [link to relevant documentation]. Figure 5 The first linearly polarized light beam is first converted into circularly polarized light after passing through the phase retarder 24. This circularly polarized light is then reflected by surface A 22 and passes through the phase retarder 24 again, where it is modulated into a second linearly polarized light beam (e.g., P-polarized light) orthogonal to the first linearly polarized state. After this conversion, the light beam carrying stray energy returns to the light-transmitting dust cover 5 in the second linearly polarized state. Because its polarization state is orthogonal to the transmission axis of the polarizing element 7, this portion of the light beam is effectively intercepted and blocked, preventing it from entering the windshield 6 area and forming visible virtual image interference.

[0047] Therefore, the diffusion component 2 provided in this application transcends the limitations of traditional diffusers that only possess light diffusion functions. By integrating a phase retardation function on the B-side 23 of its glass substrate, it constitutes a double-sided composite optical device with polarization state management capabilities. This design cleverly utilizes the different effects of polarization characteristics in the forward and reverse light paths to achieve efficient suppression of stray light paths while maintaining the original compactness of the optical system. This dual-function integrated design represents a significant advancement and innovation of this application compared to existing technologies.

[0048] Optionally, the first linear polarization state is an S-polarized state and the second linear polarization state is a P-polarized state; or, the first linear polarization state is a P-polarized state and the second linear polarization state is an S-polarized state.

[0049] The head-up display device provided in this application includes a reflector assembly, see [link to application]. Figure 3 In one example, the reflector assembly includes a folding reflector 3 and a curved reflector 4, which can be used to reflect and amplify the projected light from the diffusion assembly 2. Furthermore, after receiving the projected light output from the diffusion assembly 2, the folding reflector 3 can reflect and adjust the direction of the projected light path. The curved reflector 4 is used to further reflect and amplify the projected light path, enabling the projected light to be accurately transmitted to subsequent components, ensuring the integrity and clarity of the image.

[0050] The head-up display device provided in this application embodiment includes a light-transmitting dust cover 5. See also Figures 3 to 5 The light-transmitting dust cover 5 is located above the reflector assembly, the diffuser assembly 2, and the image generation unit 1, and serves to protect these optical components. Furthermore, due to its light-transmitting properties, it does not affect the transmission of projected light. A polarizing element 7 is disposed on any surface of the light-transmitting dust cover 5. This polarizing element 7 is configured to selectively transmit first linearly polarized light while blocking second linearly polarized light; that is, it can transmit S-polarized light while blocking P-polarized light.

[0051] During the projection imaging process (i.e., the first optical path, or the forward optical path), the light-transmitting dust cover 5 allows specific linearly polarized light, such as S-polarized light, to pass through to form a virtual image. However, during sunlight backflow (i.e., the second optical path, or the reverse optical path), the light-transmitting dust cover 5 can block unwanted linearly polarized light, such as P-polarized light, to prevent stray light from entering the human eye.

[0052] The head-up display device provided in this application embodiment is a car windshield head-up display, which also includes the car's windshield 6. The windshield 6 serves as the interface on which the projected light is finally projected, receiving the projected light after it has been processed by the front components. The driver observes the illuminated area of ​​the windshield 6 and sees a virtual image surface on the outside of the windshield to obtain vehicle instrument information.

[0053] In the field of automotive electronics, head-up displays (HUDs) are components that can display key information on the windshield of a car, playing an important role in ensuring driving safety, and their applications are becoming increasingly widespread.

[0054] Traditional HUD systems mainly use DLP PGU or LCOS PGU optical structure schemes. The following uses the DLP PGU scheme as an example to explain its working principle and the problems of exposure under sunlight.

[0055] The light propagation process of a traditional DLP PGU optical structure is as follows, see below. Figure 2 : First, the image generation unit 1 (i.e., DLP PGU) is illuminated under driving action, generating and outputting projected light rays with a specific angle of diffusion. These projected light rays are then transmitted to the diffuser 2'. The diffuser 2' plays a crucial role in imaging, light deflection, and further magnification. After receiving the projected light rays from the DLP PGU, it images, deflects, and magnifies them, then transmits the magnified projected light rays to the reflective folding mirror 3. The reflective folding mirror 3 receives the projected light rays, reflects them, and adjusts the direction of the projected light path so that the projected light rays can be accurately transmitted to the curved reflector 4. The curved reflector 4 further reflects and magnifies the projected light rays, transmitting the magnified light path to the light-transmitting dust cover 5. The main function of the light-transmitting dust cover 5 is to transmit light, transmitting the light beam to the windshield 6. Finally, the driver observes the illuminated area of ​​the windshield from the observation point and can observe the virtual image surface on the outside of the windshield, thereby obtaining vehicle instrument information.

[0056] However, traditional DLP PGU optical structures have two prominent problems under sunlight, see [link to relevant documentation]. Figure 1 On the one hand, based on the principle of light reversibility, when ambient light (including sunlight) shines on the HUD system, the internal amplification optical path will converge the ambient light to the diffuser 2', forming a converged light spot carrying high energy. Because the ambient light (including sunlight) energy is concentrated, under continuous irradiation, the diffuser 2' may locally become overheated and face the risk of damage. This not only affects the normal imaging function of the HUD system but may also shorten its lifespan and increase maintenance costs. On the other hand, a "white frame effect" will occur. When ambient light (including sunlight) shines through the vehicle's windshield 6 into the HUD system, it can directly illuminate the diffuser 2'. Due to the diffuse reflection effect on the surface of the diffuser 2', some of the reflected ambient light (including sunlight) will travel along a specific path (such as... Figure 2The light (as shown by the dashed arrow) returns to the optical path and is reflected twice back to the observation point. This causes the driver to see stray light caused by ambient light (including sunlight) when actually observing the virtual image, significantly reducing the contrast of the virtual image and creating a white frame around it. This severely interferes with the driver's accurate acquisition of instrument information, greatly reducing the HUD's user experience and driving safety.

[0057] Based on the two core problems of existing traditional DLP PGU optical structure solutions being exposed to sunlight, the solution provided in this application achieves the following significant beneficial effects through innovative design: (1) Suppressing the risk of overheating due to sunlight backflow: This application introduces a light-transmitting dust cover 5 with a polarizing element 7 into the head-up display device. Through a physical interception mechanism, approximately 50% of the sunlight energy, i.e., the second linearly polarized light, such as P-polarized light, is effectively intercepted before entering the head-up display device. Combined with the phase delay function added to the diffuser component 2, the remaining first linearly polarized light, such as S-polarized light, is converted into second linearly polarized light, such as P-polarized light, and then intercepted again. Actual measurements have verified that this design can reduce the surface temperature of the diffuser component 2 by more than 40% compared to traditional solutions, completely eliminating the risk of overheating damage caused by sunlight convergence and significantly improving device reliability.

[0058] (2) Eliminating the white-frame effect and improving image quality: Addressing the contrast reduction problem caused by the secondary incident point of diffused light in traditional solutions, this application utilizes the polarization state conversion mechanism of the diffusion component 2 to convert stray light, for example, from an S-polarized state to a P-polarized state. Combined with the polarization interception function of the light-transmitting dust cover 5, this achieves a stray light suppression rate of over 95%. Actual test data shows that the virtual image contrast is significantly improved compared to traditional HUD solutions, and the white-frame effect is essentially eliminated, ensuring that the driver can clearly obtain instrument information even in bright sunlight. Here, the S-polarized state is, for example, the first linear polarization state mentioned above, and the P-polarized state is, for example, the second linear polarization state mentioned above.

[0059] The optical solution provided in this application reduces overall system power consumption while maintaining high-brightness virtual image display through polarization management technology. Simultaneously, by eliminating performance degradation of optical components caused by sunlight, the lifespan of key components such as the diffuser assembly 2 is extended. This application systematically solves the core pain point of traditional HUD systems under sunlight, providing a highly reliable and low-maintenance-cost solution for the automotive display field.

[0060] See some examples in this application. Figure 4 and Figure 5The head-up display device also includes a windshield 6. In the second optical path, external ambient light is filtered sequentially by the windshield 6 and the polarization element 7 on the light-transmitting dust cover 5 to form a first linearly polarized light. The first linearly polarized light is reflected by the mirror group and incident on the B-side 23. After passing through the phase delayer 24 on the B-side for the first time, the first linearly polarized light is converted into circularly polarized light. After propagating through the substrate 21 and being reflected by the A-side 22, it passes through the phase delayer 24 on the B-side for the second time and is converted into a second linearly polarized light. The second linearly polarized light is reflected back to the light-transmitting dust cover 5 by the mirror group and is intercepted by the polarization element 7.

[0061] The example provided in this application describes the second optical path (reverse optical path), i.e., the case of sunlight flowing backward.

[0062] First, ambient light (such as sunlight) enters from the outside and passes sequentially through the windshield 6 and the light-transmitting dust cover 5 of the HUD system. The light-transmitting dust cover 5 integrates a polarizing element 7, which filters the incident light and allows only light of a specific polarization state to pass through, forming first linearly polarized light (e.g., S-polarized light).

[0063] The first linearly polarized light then enters the array of mirrors inside the HUD, and after being reflected by these mirrors, the light is guided to the B-plane 23 with the phase delayer 24.

[0064] When the first linearly polarized ray first passes through the phase retarder 24 on surface B 23, its polarization state changes from linearly polarized to circularly polarized. This change is due to the phase retarder's specific delay treatment of the ray's phase. After being reflected by surface A 22, the circularly polarized ray passes through the phase retarder 24 again. On the second pass through the phase retarder 24, the circularly polarized ray is converted back to linearly polarized, but its polarization state is different from that at the first incident point, becoming a second linearly polarized ray (e.g., a P-polarized ray).

[0065] The second linearly polarized light is reflected again by the mirror assembly and returns to the light-transmitting dust cover 5. Since the polarization element 7 on the light-transmitting dust cover 5 only allows light of a specific polarization state (such as S-polarized light) to pass through, the second linearly polarized light (such as P-polarized light) is intercepted by the polarization element 7 and cannot continue to propagate to the windshield 6 and enter the human eye, thereby effectively reducing the impact of stray light on the HUD imaging quality.

[0066] Through this design, the head-up display (HUD) of this application can significantly reduce stray light generated under backlight conditions such as sunlight backflow, improve the contrast and clarity of the image, thereby enhancing the driver's visual experience and driving safety. This process embodies the core idea of ​​optimizing the optical path structure of the HUD in this application to address diffuse stray light.

[0067] In traditional HUD systems, the diffuse reflection properties of the diffuser 2' cause high-energy light spots to form when sunlight shines back. This application solves the problem of existing technologies by introducing a newly designed diffuser component 2, which converts stray light polarization into a second linearly polarized state (such as P-polarized light) that is intercepted by the light-transmitting dust cover 5.

[0068] This application's example achieves precise control of the polarization optical path through the design of a double-sided composite optical structure for the diffusion component 2. This maintains the high imaging quality of the head-up display device while fundamentally solving the problem of sunlight backflow, representing a significant breakthrough in the engineering of polarization optics in the field of automotive displays.

[0069] See some examples in this application. Figure 3 and Figure 4 In the first optical path, the projection light output by the image generation unit 1 is natural light, which is deflected and diffused by the microstructure array 221 on the A surface 22 before being projected onto the B surface 23.

[0070] The example provided in this application describes the first optical path (forward optical path), i.e., the projection optical path. Please refer to [link to relevant documentation]. Figure 4 : Image generation unit 1 (such as DLP PGU) generates the image required for projection and outputs natural light. Here, natural light refers to mixed light that has not undergone polarization processing and contains light rays of all polarization directions.

[0071] The A-side 22 is designed with a microstructure array 221, which can deflect and diffuse incident natural light. The deflection effect changes the direction of light propagation, while the diffusion effect makes the light more uniformly distributed in space, which helps to form a clearer projected image.

[0072] The light, after being processed by the microstructure array on surface A 22, continues to be projected onto surface B 23. A phase retarder 24 is attached to surface B 23, but it is specifically noted in this example description that the polarization state of the natural light after passing through the phase retarder 24 is not modulated. This means that although the light passes through the phase retarder 24, since the input is natural light (containing all polarization directions), the phase retarder does not significantly affect or change the polarization state of the light. In other words, for natural light, the effect of the phase retarder 24 at this stage is "hidden" or not apparent because natural light itself does not have a single polarization direction, so the phase retarding effects cancel each other out overall, without changing the polarization state distribution of the output light.

[0073] The light processed by the diffusion component 2 will continue to be reflected and magnified by the reflector group, and finally projected onto the windshield 6 to form a virtual image for the driver to observe.

[0074] Although the phase delayer 24 of surface B 23 does not modulate the polarization state of natural light at this stage, this design provides flexibility for possible polarization control later. In particular, when dealing with incident light of a specific polarization state (such as polarized light generated by sunlight backflow), the phase delayer 24 can play a key role in reducing the influence of stray light by changing the linear polarization state of the light.

[0075] It should be noted that in the first optical path, the projected light output by the image generation unit 1 is natural light, and the natural light remains natural light after passing through the phase delayer.

[0076] See some examples in this application. Figures 3 to 5 The polarization element 7 disposed on the surface of the light-transmitting dust cover 5 is a reflective polarization film layer, which is configured to: allow first linearly polarized light to pass through; and be able to block second linearly polarized light to prevent the second linearly polarized light from entering the windshield 6 area.

[0077] The reflective polarizing film layer can be bonded to any surface of the light-transmitting dust cover 5, for example, using optical adhesive (OCA). When bonding the reflective polarizing film layer, it is necessary to ensure that it is completely conformal to the surface of the light-transmitting dust cover 5 and free of air bubbles.

[0078] In some examples of this application, the phase delayer 24 is a quarter-wave plate, which can achieve a 90° phase delay of the polarization state of light.

[0079] The phase delayer 24 (e.g., a quarter-wave plate, QWP) is attached, for example, to the B-side 23 of the diffuser assembly 2.

[0080] In some examples of this application, the substrate 21 is a glass plate, and the thickness of the substrate 21 is 0.3 mm to 1 mm.

[0081] A glass substrate with a thickness of 0.3 mm to 1 mm can provide stable support for the microstructure array 221 and the phase delayer 24. The microstructure array 221 is also easily fabricated on a glass substrate of this thickness.

[0082] In addition, this thickness design of the substrate 21 of the diffusion component 2 will not increase the overall weight and manufacturing cost of the device.

[0083] In some examples of this application, the microstructure array 221 is formed on the A-side 22 by a nanoimprint process, and the microstructure array 221 is used to deflect and diffuse the projected light output by the image generation unit 1.

[0084] The microstructure array 221 is located on surface 22 of the diffusion component 2 and is mainly used to deflect and diffuse the projection light output by the image generation unit 1.

[0085] The microstructure array 221 can be a periodically arranged microstructure or a randomly arranged microstructure. This application does not impose any specific restrictions on this.

[0086] In some examples of this application, the image generation unit 1 is a DLP PGU or an LCOS PGU.

[0087] See some examples in this application. Figures 3 to 5 The reflector assembly includes a reflective folding mirror 3 and a curved reflector 4 sequentially disposed between the diffusion component 2 and the light-transmitting dust cover 5; wherein, the reflective folding mirror 3 is used to reflect and adjust the light path; and the curved reflector 4 is used to reflect and amplify the light path.

[0088] In this application, the reflective folding mirror 3 and the curved reflective mirror 4 can compress the size of the device through optical path folding, thereby achieving a balance between miniaturization and high imaging quality in the head-up display device, which is especially suitable for vehicle-mounted HUD scenarios with strict requirements for space and safety.

[0089] According to another embodiment of this application, a method for suppressing stray light in a head-up display device is provided, comprising the following steps, see below. Figure 5 : The external ambient light is filtered by the polarization element 7 on the light-transmitting dust cover 5 to obtain the first linearly polarized light. The first linearly polarized light is guided to the diffusion component 2, so that the first linearly polarized light can pass through the phase delayer 24 disposed on the B surface 23 of the diffusion component 2 twice, so as to convert the first linearly polarized light into the second linearly polarized light; wherein, the A surface of the diffusion component 2 is configured in the optical path to reflect ambient light from the outside to the B surface 23; The second linearly polarized light is guided back to the light-transmitting dust cover 5, and the polarization element 7 is used to intercept the second linearly polarized light, so that the second linearly polarized light does not enter the windshield 6 area, thereby eliminating stray light interference.

[0090] In the above steps, the first linearly polarized ray is, for example, S-polarized light, and the second linearly polarized ray is, for example, P-polarized light.

[0091] It should be noted that the stray light suppression method for the head-up display device provided in this application embodiment illustrates the second optical path in this application.

[0092] This application provides a method for suppressing stray light in head-up display devices. Its core mechanism lies in the synergistic effect of polarization state conversion, secondary reflection, and polarization beam splitting to effectively eliminate stray light interference.

[0093] The specific steps are as follows: First, the incident ambient light is filtered using the polarization element 7 integrated on the light-transmitting dust cover 5, allowing only the first linearly polarized light (such as S-polarized light) to pass through, forming an initial polarized beam. Subsequently, this S-polarized light is guided to the diffusion assembly 2, where it undergoes two penetrations through the phase retarder 24 disposed on the B-side 23, and is reflected by the A-side 22 in between. During this process, the phase retarder 24 modulates the phase of the S-polarized light, converting it into a second linearly polarized light, such as P-polarized light, after the two penetrations.

[0094] The resulting P-polarized beam is redirected back to the light-transmitting dust cover 5. At this point, the polarization element 7 performs its beam-splitting and interception function, effectively blocking the P-polarized light from entering the imaging area of ​​the windshield 6, thereby completely eliminating stray light interference. It is worth noting that this scheme, while blocking P-polarized stray light, ensures that the original S-polarized projection light can pass through the light-transmitting dust cover 5 normally, maintaining the integrity of the virtual image projection.

[0095] Through this dual polarization state management strategy, this application achieves three major technical advantages: first, it completely eliminates stray light in the windshield imaging area, significantly improving the contrast of the virtual image; second, it reduces the risk of glare caused by sunlight backflow through the polarization selection mechanism; and third, it maintains the transmission efficiency of the projection light path, ensuring the display stability of the head-up display device in strong light environments.

[0096] This solution is particularly suitable for automotive windshield HUD systems, and can effectively solve traditional technical problems such as diffuser damage caused by sunlight backflow and white frame effect.

[0097] The imaging method for the head-up display device provided in this application embodiment is as follows: See Figure 4 : The image generation unit 1 outputs projected light rays; wherein, the projected light rays are natural light. The projected light is first deflected and diffused by the A surface 22 of the diffusion component 2, and then remains polarized when it passes through the phase delayer 24 of its B surface 23 before being projected onto the reflector group. The projected light is reflected by the reflector group to the light-transmitting dust cover 5; The first linearly polarized light, such as S-polarized light, in the projected light is transmitted through the light-transmitting dust cover 5 and then transmitted to the windshield 6, ultimately forming a virtual image.

[0098] It should be noted that the second linearly polarized light, i.e., P-polarized light, in the projected light beam will be intercepted by the polarization element 7 installed on the light-transmitting dust cover 5 when it passes through the cover.

[0099] exist Figure 4 The observation point shown (the position of the human eye) observes the illuminated area of ​​the windshield 6, and a virtual image surface can be observed on the outside of the windshield.

[0100] When the Brewster angle (the angle between the windshield 6 and the transmitted light emitted from the image generation unit 1) of the head-up display device and windshield 6 provided in this application is 55°, the brightness loss of the P-polarized light (second polarized light) is very small, close to 0. See [reference needed]. Figure 6 .exist Figure 6 In the diagram, the two green dashed curves represent the reflectivity ratio of s-polarized light to p-polarized light, the blue solid curve represents p-polarized light, and the blue virtual curve represents s-polarized light.

[0101] According to yet another embodiment of this application, a vehicle is provided that includes a head-up display device as described above.

[0102] The specific implementation of the vehicle in this application embodiment can refer to the various embodiments of the head-up display device described above, and therefore has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0103] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0104] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A head-up display device, characterized in that, Including those arranged sequentially along the projection light path: Image generation unit (1) is used to output projected light rays; The diffusion component (2) includes a substrate (21), the substrate (21) including an A-side (22) facing the image generation unit (1) and a B-side (23) facing away from the image generation unit (1), the A-side being provided with a microstructure array (221), and the B-side (23) being provided with a phase delayer (24); wherein, the A-side (22) is configured in a first optical path to transmit projected light, and the A-side (22) is configured in a second optical path to reflect ambient light from the outside to the B-side (23). The reflector group is capable of reflecting and amplifying the projected light from the diffusion component (2), and guiding external ambient light to the diffusion component (2). A light-transmitting dust cover (5) has polarizing elements (7) on its surface.

2. The head-up display device according to claim 1, wherein the head-up display device further includes a windshield (6), characterized in that, In the second optical path, the ambient light from the outside is filtered sequentially by the polarization element (7) on the windshield (6) and the light-transmitting dust cover (5) to form a first linearly polarized light. The first linearly polarized light is reflected by the mirror group and then incident on the B surface (23). After the first linearly polarized light passes through the phase delayer (24) on the B surface for the first time, it is converted into circularly polarized light. After propagating through the substrate (21) and being reflected by the A surface (22), it passes through the phase delayer (24) on the B surface for the second time and is converted into a second linearly polarized light. The second linearly polarized light is reflected back to the light-transmitting dust cover (5) by the mirror group and is intercepted by the polarization element (7).

3. The head-up display device according to claim 1 or 2, characterized in that, In the first optical path, the projection light output by the image generation unit (1) is natural light, which is deflected and diffused by the microstructure array (221) on the A surface (22) and then projected onto the B surface (23).

4. The head-up display device according to claim 2, characterized in that, The polarizing element (7) disposed on the surface of the light-transmitting dust cover (5) is a reflective polarizing film layer, which is configured as follows: Allowing light of the first linearly polarized state to pass through; and It can intercept the second linearly polarized light to prevent the second linearly polarized light from entering the windshield (6) area.

5. The head-up display device according to claim 1, characterized in that, The phase delayer (24) is a quarter-wave plate, which can achieve a 90° phase delay of the polarization state of light.

6. The head-up display device according to claim 1, characterized in that, The substrate (21) is a glass plate, and the thickness of the substrate (21) is 0.3mm~1mm.

7. The head-up display device according to claim 1, characterized in that, The microstructure array (221) is formed on the A-side (22) by nanoimprinting process. The microstructure array (221) is used to deflect and diffuse the projected light output by the image generation unit (1).

8. The head-up display device according to claim 1, characterized in that, The image generation unit (1) is a DLP PGU or an LCOS PGU.

9. The head-up display device according to claim 1, characterized in that, The reflector assembly includes components sequentially disposed between the diffusion assembly (2) and the light-transmitting dust cover (5): The reflecting folding mirror (3) is used to reflect and adjust the light path; and, Curved mirror (4) is used for secondary reflection and amplification of the light path.

10. A method for suppressing stray light in a head-up display device, characterized in that, include: The first linearly polarized light is obtained by filtering the ambient light from the outside through the polarization element (7) on the light-transmitting dust cover (5); The first linearly polarized light is guided to the diffusion component (2), so that the first linearly polarized light can pass through the phase delayer (24) provided on the B surface (23) of the diffusion component (2) twice, so as to convert the first linearly polarized light into the second linearly polarized light; wherein, the A surface of the diffusion component (2) is configured in the optical path to reflect ambient light from the outside to the B surface (23). The second linearly polarized light is guided back to the light-transmitting dust cover (5), and the polarization element (7) is used to intercept the second linearly polarized light so that the second linearly polarized light will not enter the windshield (6) area, thereby eliminating stray light interference.

11. A vehicle, characterized in that, include: The head-up display device as described in any one of claims 1-9.

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