Image generation unit, head-up display device and vehicle

Abstract

The embodiment of the invention provides an image generation unit, a head-up display device and a vehicle. Wherein the image generation unit comprises an illumination light source, a collimating lens array and a display assembly which are sequentially arranged along the light transmission direction; the illumination light source provides illumination light; the collimating lens array is used for converting the illumination light into a collimated light beam; the display assembly comprises a liquid crystal screen, a first heat dissipation optical medium layer and a second heat dissipation optical medium layer, and the first heat dissipation optical medium layer and the second heat dissipation optical medium layer are glued to the back side and the light emitting side of the liquid crystal screen respectively. The beam expanding module is used for forming beam expanding light matched with an amplification light path in the vehicle-mounted head-up display equipment; an infrared high-reflection film is arranged between the liquid crystal screen and the second heat dissipation optical medium layer and used for reflecting infrared band light so as to reduce heat input. The thermal conductivity of the first heat dissipation optical dielectric layer and the thermal conductivity of the second heat dissipation optical dielectric layer are both not lower than 2 W / mK.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical display technology. More specifically, the embodiments of the present application relate to an image generation unit, a head-up display device, and a vehicle. Background Art

[0002] As an automotive electronic component that can display information on the front windshield of a car, the car's head-up display (HUD) greatly facilitates the driver's observation of vehicle instrument information, effectively ensures driving safety, and is increasingly widely used in the automotive field.

[0003] Traditional HUD systems illuminate the image generation unit to obtain a projected image, which is then reflected through the head-up display's internal amplified optical path and output to the car's windshield to form a virtual image. In the traditional HUD TFT PGU optical solution, after the LED array is driven and illuminated by current, it transmits light with a large angle of diffusion to a collimator. This device, for example, uses a biconvex lens to converge the light beam. The beam is then processed through a beam expander and diffuser before being transmitted to the TFT (liquid crystal display). Finally, the light beam is imaged by the TFT and transmitted to the back-end HUD optical system. However, this solution has the following significant drawbacks: (1) Overheating caused by backflow of sunlight: Due to the reversible principle of light, the internal optical path of the HUD will converge strong light outside the vehicle (such as sunlight) to the picture generation unit (PGU), forming a high-energy convergent light spot, causing local overheating of the TFT. In extreme cases, it may damage the components. Conventional heat dissipation solutions are difficult to take into account both the requirements of rapid heat conduction and temperature rise delay.

[0004] (2) Complex optical system: The beam expander group and independent heat dissipation structure make the system bulky. The cumulative optical efficiency loss between optical components reaches 8% (calculated based on the 4% loss on one side of the injection-molded lens), and the structure needs to be designed separately for each lens, which increases the overall complexity and manufacturing cost.

[0005] (3) Backlight heat accumulation and thermal radiation attenuation: The heat generated by the high-power LED backlight accumulates on the back side of the TFT, affecting the display stability; at the same time, the long-term effect of infrared thermal radiation will cause the performance of optical components such as beam expanders and diffusers to degrade, shortening the service life of the equipment. Summary of the Invention

[0006] The purpose of this application is to provide a new technical solution for an image generation unit, a head-up display device and a vehicle.

[0007] In a first aspect, the present application provides an image generation unit for a head-up display device, wherein the image generation unit includes: A lighting source, used to provide lighting light; a collimating lens array, configured to convert the illumination light into a collimated light beam; and Display components, including: LCD screen; a first heat-dissipating optical medium layer, bonded to the back side of the liquid crystal screen, with an optical microstructure layer provided on its light-incident side surface, the optical microstructure layer being configured to diffuse the collimated light beam into an expanded light beam that matches the amplified optical path within the head-up display device; A second heat dissipation optical medium layer is glued to the light-emitting side of the liquid crystal screen, and an infrared high-reflection film is provided between the second heat dissipation optical medium layer and the liquid crystal screen. The infrared high-reflection film is used to reflect infrared light to reduce heat input; Wherein, the thermal conductivity of the first heat dissipation optical medium layer and the second heat dissipation optical medium layer are both not less than 2 W / mK.

[0008] Optionally, the light-emitting side surface of the second heat-dissipating optical medium layer is provided with an anti-glare film for suppressing optical ghosting.

[0009] Optionally, the first heat dissipation optical medium layer and the second heat dissipation optical medium layer are respectively bonded to the liquid crystal screen via optical adhesive layers, wherein: the thermal conductivity of the optical adhesive layer is 0.1W / mK~0.3W / mK, and the thickness of the optical adhesive layer is 100μm~400μm.

[0010] Optionally, the optical adhesive layer is optically transparent resin OCR or optically transparent adhesive OCA.

[0011] Optionally, the first heat dissipation optical medium layer and the second heat dissipation optical medium layer are both made of thermally conductive glass or thermally conductive plastic.

[0012] Optionally, the optical microstructure layer is a single-sided structure, and its microstructure surface faces the illumination light source; The optical microstructure layer includes a plurality of microstructure units, wherein each of the microstructure units is a free-form convex mirror, and the aperture size of each microstructure unit is 20 μm to 30 μm.

[0013] Optionally, the plurality of free-form convex mirrors in the optical microstructure layer are arranged in an array or randomly; The optical etendue of each free-form convex mirror is determined by the following relationship: The horizontal expansion H is: H = 2arcsin [EB (H) × sin FOV (H) / 2] / Display (H)]; The longitudinal expansion V is: V = 2arcsin [EB (V) × sin FOV (V) / 2] / Display (V)]; Where: EB(H) and EB(V) represent the eye box sizes in the horizontal and vertical directions, respectively; FOV (H) and FOV (V) represents the field of view in the horizontal and vertical directions, respectively; Display (H) and Display (V) represents the horizontal size and vertical size of the LCD display screen respectively.

[0014] Optionally, the optical microstructure layer is transferred to the light incident side surface of the first heat dissipation optical medium layer by nanoimprinting; or The optical microstructure layer is formed on the light incident side surface of the first heat dissipation optical medium layer by etching.

[0015] Optionally, the infrared high-reflection film and the anti-glare film are deposited on the opposite side surfaces of the second heat dissipation optical medium layer by evaporation or magnetron sputtering.

[0016] Optionally, the display assembly is tilted relative to the collimating lens array to match the rear-end optical path imaging requirements; The liquid crystal screen in the display component is a TFT LCD liquid crystal screen.

[0017] Optionally, the lighting light source adopts a partitioned controllable LED array structure, which is configured to independently control the brightness of each partitioned LED, thereby providing lighting light with a local dimming function.

[0018] Optionally, the image generating unit further includes a fixing bracket, and the illumination light source, the collimating lens array and the display assembly are all arranged on the fixing bracket.

[0019] In a second aspect, the present application provides a head-up display device, which includes: the image generation unit described in the first aspect, a reflector group and a windshield of a vehicle, wherein the reflector group reflects the output light of the image generation unit to the windshield to form a virtual image.

[0020] In a third aspect, the present application provides a vehicle, comprising: A head-up display device as described in the second aspect.

[0021] The beneficial effects of this application are as follows: The image generation unit provided in the embodiment of the present application, by providing a first heat-dissipating optical medium layer with an optical microstructure layer, not only forms a beam expansion light that matches the optical path and increases the heat dissipation area, but also utilizes its high thermal conductivity (≥2W / mK) to quickly conduct the heat generated by the backflow of sunlight, thereby effectively avoiding local overheating of the liquid crystal screen; at the same time, an infrared high-reflective film is provided between the second heat-dissipating optical medium layer and the liquid crystal screen to reflect infrared band light to reduce heat input, and combined with the double-layer high thermal conductivity medium (≥2W / mK) to further delay the temperature rise, effectively solving the problems of overheating caused by backflow of sunlight, insufficient heat dissipation efficiency, and component performance degradation caused by infrared thermal radiation in traditional solutions.

[0022] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0024] Figure 1 This is a structural diagram of an image generation unit according to an embodiment of the present application; Figure 2 This is a schematic diagram of the structure of a traditional HUD system; Figure 3 This is a structural diagram of a traditional PGU system.

[0025] Description of reference numerals: 1. Illumination light source; 2. Collimating lens array; 3. First heat dissipation optical medium layer; 4. Optical microstructure layer; 5. Optical adhesive layer; 6. LCD screen; 7. Infrared high-reflection film; 8. Anti-glare film; 9. Second heat dissipation optical medium layer; 10. Fixed bracket; 11. Diffuser; 12. First beam expander; 13. Second beam expander; 14. Windshield; 15. Curved mirror; 16. Folding mirror. DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0027] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0028] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0029] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0030] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0031] The following describes in detail an image generation unit, a head-up display device, and a vehicle provided in an embodiment of the present application in conjunction with the accompanying drawings.

[0032] According to one embodiment of the present application, an image generation unit is provided for a head-up display device, see Figure 1 The image generation unit includes an illumination light source 1, a collimating lens array 2, and a display assembly arranged in sequence along the light transmission direction. The illumination light source 1 is used to provide illumination light. The collimating lens array 2 is used to convert the illumination light into a collimated light beam. The display assembly includes a liquid crystal screen 6, a first heat dissipation optical medium layer 3, and a second heat dissipation optical medium layer 9; the first heat dissipation optical medium layer 3 is glued to the back side of the liquid crystal screen 6, and an optical microstructure layer 4 is provided on its light-incident side surface. The optical microstructure layer 4 is used to diffuse the collimated light beam into an expanded light beam that matches the amplified light path in the head-up display device; the second heat dissipation optical medium layer 9 is glued to the light-outlet side of the liquid crystal screen 6, and an infrared high-reflection film 7 is provided between the liquid crystal screen 6 and the liquid crystal screen 6. The infrared high-reflection film 7 is used to reflect infrared band light to reduce heat input. The thermal conductivity of the first heat dissipation optical medium layer 3 and the second heat dissipation optical medium layer 9 is not less than 2W / mK.

[0033] The image generation unit (PGU) provided in the embodiments of the present application is specifically designed to address multiple core problems existing in traditional in-vehicle HUD devices (in-vehicle head-up display devices) - local overheating of the LCD screen caused by sunlight backflow, spatial redundancy caused by complex optical structures, display instability caused by backlight LED heat accumulation, and optical component performance degradation caused by infrared thermal radiation. Through the integrated design of a new optical structure and an efficient heat dissipation structure, a significant improvement in overall performance is achieved.

[0034] The picture generation unit (PGU) provided in this application embodiment is specifically designed and optimized for head-up displays (HUDs), particularly in-vehicle HUDs. While ensuring high-brightness virtual image display, it also streamlines the optical structure and enhances thermal management, effectively adapting to the limited installation space in vehicles and extending the life of the HUD.

[0035] The main components of the image generation unit provided in the embodiment of the present application are described below.

[0036] See also Figure 1 , the image generation unit provided in the embodiment of the present application includes an illumination light source 1.

[0037] In the picture generation unit (PGU) provided in the embodiments of the present application, the illumination light source 1 is, for example, a light-emitting diode (LED) array. As the source of illumination light, the core function of the illumination light source 1 is to provide high-brightness illumination light for the head-up display (HUD), ensuring that the virtual image projected onto the vehicle windshield has sufficient clarity and contrast to meet the information readability requirements in driving scenarios.

[0038] In terms of power design, the illumination light source 1 should strike a balance between brightness output and thermal management. While high-power LEDs can improve brightness, traditional solutions suffer from significant backlight heat accumulation. Continuous exposure can easily lead to localized overheating of the LCD screen and even component damage. This application effectively addresses this issue through a novel heat dissipation design, such as the rational combination of a double-layer heat-dissipating optical medium layer (a first heat-dissipating optical medium layer 3 and a second heat-dissipating optical medium layer 9) with an optical microstructure layer 4 and an infrared high-reflective film 7. This effectively reduces the risk of backlight heat accumulation to below a safe threshold while ensuring high-brightness display.

[0039] See also Figure 1 The image generation unit provided in the embodiment of the present application includes a collimating lens array 2, which is located on the light output path of the illumination light source 1.

[0040] In the image generation unit (PGU) provided in the embodiment of the present application, the collimating lens array 2 is one of the core optical components. It is responsible for converting the diffuse light emitted by the illumination light source 1 (such as an LED array) into a parallel collimated light beam, providing basic support for the matching of the subsequent optical path with the HUD amplification optical path.

[0041] See also Figure 1 , the image generation unit provided in the embodiment of the present application also includes a specially designed display component.

[0042] In the picture generation unit (PGU) provided in the present embodiment, the display assembly serves as the core imaging module, and its design primarily focuses on the dual-layer heat dissipation optical structure on opposite sides of the liquid crystal panel 6. This optical structure effectively addresses the overheating issues caused by sunlight backflow and backlight heat accumulation in traditional solutions.

[0043] Specifically, the display assembly is centered around the LCD screen 6 and forms a projected image by modulating incident light. To address the high temperature issue, in this embodiment, a first heat dissipation optical medium layer 3 and a second heat dissipation optical medium layer 9 are introduced on the back side and light-emitting side of the LCD screen 6, respectively, to construct an active heat dissipation system: The first heat dissipation optical medium layer 3 is glued to the back side of the liquid crystal screen 6, and the light incident side surface thereof is integrated with an optical microstructure layer 4. The optical microstructure layer 4 can achieve dual technical effects: (1) Optimization of optical path matching: Through microstructured surfaces (such as free-form convex mirrors), collimated light beams can be converted into expanded light that matches the amplified optical path within the entire head-up display device. This can be used to replace the multi-stage beam expansion lens group in traditional solutions. This optical design can, for example, shorten the optical path by more than 30%, significantly reducing the overall volume of the picture generation unit (PGU).

[0044] (2) Improved heat dissipation efficiency: The surface area of ​​the microstructures on the optical microstructure layer 4 is increased by 40% or even more than that of flat glass. Combined with high thermal conductivity materials, such as two heat dissipation optical medium layers with a thermal conductivity of ≥2W / mK, heat generated by the backlight LED and sunlight backflow can be quickly transferred to the entire surface of the first heat dissipation optical medium layer 3, avoiding local overheating. For example, according to experimental data, this design significantly reduces the temperature rise rate on the back side of the LCD screen 6, such as by approximately 60%.

[0045] It should be noted that a plurality of free-form convex mirror structures are distributed on the surface of the optical microstructure layer 4. These microstructures form densely distributed curved surface units through their convex morphology, which effectively increases the surface area of ​​the first heat dissipating optical medium layer 3, thereby significantly improving the heat dissipation efficiency.

[0046] The second heat dissipation optical medium layer 9 is bonded to the light-emitting side of the liquid crystal panel 6, and an infrared high-reflection film 7 is specifically disposed between the second heat dissipation optical medium layer 9 and the light-emitting side of the liquid crystal panel 6, forming a heat protection barrier. This is because the introduction of the infrared high-reflection film 7 can block infrared heat radiation.

[0047] For example, the infrared high-reflection film 7 has a reflectivity of ≥95% in the near-infrared band (such as 700nm~1100nm), effectively blocking the invisible infrared light in the sunlight and reducing heat input; at the same time, the transmittance in the visible light band (380nm~700nm) is ≥95%, ensuring that the virtual image display is not affected.

[0048] See also Figure 2 In the optical design of the traditional PGU system, a cold light film must be set between the PGU and the curved mirror 15. Figure 2The principle of the central folding mirror 16 is to reduce the thermal damage to the PGU caused by sunlight by cutting off the infrared spectrum. However, this solution has the following drawbacks: (1) the introduction of the cold light film increases the complexity of the optical system and occupies the internal space of the HUD; (2) the additional optical interface causes an approximately 4%-8% loss of light energy; (3) the cold light film installation structure needs to be designed separately, increasing the material and assembly costs.

[0049] The present application achieves the following technical improvements by directly integrating the infrared high-reflection film 7 with infrared filtering function into the second heat dissipation optical medium layer 9 in front of the liquid crystal screen 6: Completely removing the traditional cold light film and folding mirror structure shortens the optical path length. The freed-up layout space allows for more flexible HUD vehicle adaptation, especially for compact vehicles. The infrared high-reflective film 7 is directly plated on the second heat-dissipating optical medium layer 9 to improve the heat reflection efficiency. This avoids the multi-interface light loss of traditional cold light films and can improve the system light efficiency.

[0050] In addition, compared to Figure 2 The optical architecture shown in FIG2 further reduces the number of optical components, lowers production costs, and simplifies the assembly process.

[0051] In this application, the second heat-dissipating optical medium layer 9 and the first heat-dissipating optical medium layer 3 form a dual-layer, highly thermally conductive channel for the LCD panel 6. Heat conduction through these two heat-dissipating optical medium layers (with a thermal conductivity of ≥ 2 W / mK) can extend the surface temperature rise time of the LCD panel 6 by more than two times, ensuring the long-term reliability of the components.

[0052] See also Figure 3 Traditional PGU systems rely on multi-stage optical devices to achieve optical path matching: the LCD screen 6 (e.g., a TFT) in this system must be collimated and expanded by a first beam expander 12, a second beam expander 13, and a diffuser 11 (diffuser) arranged at intervals. This design leads to two major drawbacks: (1) Failure of thermal management: The heat from sunlight backflow and backlight LEDs accumulates on the surface of the LCD screen 6. Due to the lack of an effective heat dissipation path, it is easy to cause local overheating and shorten the life of components; (2) High system redundancy: The superposition of multiple lenses makes the optical path long and bulky, making it difficult to fit into the compact installation space of a vehicle.

[0053] Traditional PGU system, see Figure 3 This optical design not only increases the system structure complexity and manufacturing cost, but also reduces the overall optical efficiency due to the light loss between the multi-stage lenses (the loss of a single-side lens is about 4%).

[0054] This application achieves two core improvements through the integrated design of a double-layer heat dissipation medium layer (i.e., a first heat dissipation optical medium layer 3 and a second heat dissipation optical medium layer 9), the optical microstructure layer 4, and the infrared high-reflection film 7: (1) Simplified structure: The number of optical components is reduced (such as omitting the beam expander and diffuser), which can shorten the optical path by more than 30% and significantly reduce the system volume and weight; (2) Heat dissipation optimization: Double-layer heat dissipation optical medium (thermal conductivity ≥ 2W / mK) combined with micro-structure heat dissipation design effectively disperses sunlight backflow and backlight heat to avoid local overheating. At the same time, the infrared high-reflection film 7 blocks more than 95% of near-infrared heat input, ensuring long-term reliability of the equipment.

[0055] In short, this application eliminates the need for a beam expander and diffuser through the coordinated design of a collimating lens array 2 and a subsequent optical microstructure layer 4. This design shortens the optical path by over 30%, significantly reducing the volume of the entire image generation unit. Furthermore, by reducing the number of optical components, the overall light efficiency is increased by 8% (calculated based on a 4% loss on one side of the injection-molded lens).

[0056] The optical design of the image generation unit provided in this embodiment solves the problem of overheating caused by sunlight backflow. In conventional solutions, strong light from outside the vehicle (such as sunlight) converges through the HUD optical path onto the LCD screen 6, creating a high-energy spot and causing overheating. However, this embodiment utilizes a highly reflective infrared film 7 to reflect infrared light, reducing heat input. Simultaneously, a double layer of high-heat dissipation dielectric material (thermal conductivity ≥ 2 W / mK) rapidly conducts heat, preventing localized heat accumulation. The optical microstructure layer 4 further increases the heat dissipation area and improves thermal radiation efficiency. These three factors work together to achieve efficient heat dissipation.

[0057] The optical design of the image generation unit provided in the embodiments of this application simplifies the optical system and improves space utilization. Conventional solutions require optical path matching through a beam expander and diffuser, resulting in a bulky PGU system and low optical efficiency (4% loss per lens on a single side). This embodiment of the application directly generates the expanded light through the optical microstructure layer 4, omitting the beam expander and diffuser. This shortens the optical path by over 30%, resulting in a more compact overall structure that fits within the limited installation space of a vehicle.

[0058] The optical design of the image generation unit provided in the embodiments of the present application can suppress backlight heat accumulation and thermal radiation attenuation. In traditional solutions, heat generated by high-power LED backlights accumulates on the backside of the LCD screen, affecting display stability; at the same time, infrared thermal radiation causes optical component performance degradation. The embodiments of the present application utilize the high thermal conductivity of the first heat-dissipating optical medium layer 3 to quickly conduct backlight heat, preventing accumulation. The infrared high-reflective film 7 reduces infrared light input, slowing component performance degradation and extending the device's service life.

[0059] The optical design of the image generation unit provided in this embodiment improves optical efficiency and imaging quality. The optical microstructure layer 4 is rationally designed through the MLA (microlens array) and can be customized to match the HUD rear-end optical path, reducing light efficiency loss.

[0060] This embodiment of the application addresses several key pain points of traditional HUD systems through novel optical and heat dissipation structural designs: overheating from sunlight backflow, optical system redundancy, backlight heat accumulation, and infrared thermal radiation attenuation. The technical benefits are reflected in efficient heat dissipation, compact structure, stable display, and improved image quality, providing key technical support for the miniaturization, high reliability, and long life of automotive HUD equipment.

[0061] In some examples of this application, see Figure 1 The light-emitting surface of the second heat-dissipating optical medium layer 9 is provided with an anti-glare film 8 for suppressing optical ghosting.

[0062] In the example provided in this application, an anti-glare film 8 is added to the light-emitting side surface of the second heat-dissipating optical medium layer 9. This design significantly improves the imaging quality of the HUD by suppressing optical ghosting.

[0063] In traditional HUD systems, variations in glass thickness cause light to reflect multiple times between the vehicle's windshield and the PGU (Picture Generating Unit) system, creating a "ghosting" phenomenon. This ghosting reduces the clarity of the virtual image and, especially in bright light conditions (such as direct sunlight), can interfere with the driver's ability to read instrument information, posing a safety hazard.

[0064] The anti-glare film 8 design proposed in this example of the present application can process incident light, and its technical effects are reflected in the following aspects: The anti-glare film 8 can evenly disperse the light reflected twice by the vehicle's windshield to avoid forming a clear ghosting outline; While scattering the reflected light, the anti-glare film 8 has minimal effect on the transmittance of the main imaging light emitted by the liquid crystal screen 6 (visible light transmittance ≥ 95%), ensuring that the virtual image display is not affected; Combined with the infrared high-reflective film 7's ability to block near-infrared light (reflectivity ≥ 95%), the anti-glare film 8 further reduces the interference of ambient light on imaging, thereby improving readability under strong light.

[0065] In the present application, the integrated design of the anti-glare film 8 and the second heat-dissipating optical medium layer 9 achieves functional complementarity: the anti-glare film can, for example, be directly coated on the surface of the second heat-dissipating optical medium layer 9 without the need for additional optical elements, which meets the core goal of "simplifying the structure" of the present application; the second heat-dissipating optical medium layer 9 (whose thermal conductivity is ≥2W / mK) can quickly conduct away the trace heat generated by the film layer due to light absorption, thereby avoiding degradation of the film layer performance.

[0066] According to experimental data, the design of the anti-glare film 8 introduced in this example of the present application reduces ghosting interference by more than 70%, while ensuring the stable operation of the image generation unit in a wide temperature range of -40°C to +85°C.

[0067] As can be seen, the introduction of the anti-glare film 8 significantly improves HUD image clarity by suppressing optical ghosting, ensuring driving safety, especially in bright light environments. Its coordinated design with the heat-dissipating optical dielectric layer and infrared high-reflective film 7 simplifies the system architecture while optimizing both thermal management and optical performance, providing key support for high-reliability automotive HUD applications.

[0068] In some examples of the present application, the first heat dissipation optical medium layer 3 and the second heat dissipation optical medium layer 9 are respectively glued to the liquid crystal screen 6 through an optical adhesive layer 5, wherein: the thermal conductivity of the optical adhesive layer 5 is 0.1W / mK~0.3W / mK, and the thickness of the optical adhesive layer 5 is 100μm~400μm.

[0069] In the example provided in this application, the design of the optical adhesive layer 5 is optimized to achieve efficient heat conduction between the double-layer heat dissipating optical medium layer and the liquid crystal screen 6 .

[0070] Optionally, the optical adhesive layer 5 is made of an adhesive material with a thermal conductivity of 0.1 W / mK to 0.3 W / mK.

[0071] In a specific example of the present application, the optical adhesive layer 5 is made of an adhesive material with a thermal conductivity of 0.2 W / mK.

[0072] The thermal conductivity of traditional optical adhesive layers is mostly ≤0.05W / mK. However, in the solution provided in this example of the present application, the design of the thermal conductivity of the optical adhesive layer 5 can increase the heat transfer efficiency by 3 to 6 times, significantly reducing the heat conduction resistance.

[0073] Optionally, the thickness of the optical adhesive layer 5 is controlled to be between 100 μm and 400 μm.

[0074] In a specific example of the present application, the thickness of the optical adhesive layer 5 is 200 μm.

[0075] The thickness of the conventional optical adhesive layer is usually ≥500μm. In the solution provided in this example of the present application, the thickness design of the optical adhesive layer 5 combined with the thermal conductivity design can reduce the thermal resistance by more than 60%, ensuring efficient heat conduction between the liquid crystal screen 6 and the double-layer heat dissipation optical medium layer.

[0076] The backside heat dissipation of the LCD panel 6 (with a first heat-dissipating optical medium layer 3 disposed on the backside) absorbs heat generated by the backlight LEDs and sunlight intrusion, and rapidly conducts the heat laterally through the first heat-dissipating optical medium material (thermal conductivity ≥ 2 W / mK), thereby preventing localized overheating. It should be noted that the term "lateral conduction" here refers to the ability of the heat to diffuse across the surface of the heat-dissipating medium layer.

[0077] The light-emitting side of the liquid crystal screen 6 is heat-insulated (a second heat-dissipating optical medium layer 9 is provided on the light-emitting side): the infrared high-reflection film 7 reflects more than 95% of near-infrared heat, thereby reducing external heat input.

[0078] The heat transfer function of the optical adhesive layer 5 is to quickly diffuse the heat of the local hot spot on the surface of the liquid crystal screen 6 to the entire heat dissipation medium layer as an intermediate channel, forming a closed-loop heat dissipation path of "back side heat absorption - adhesive layer heat transfer - light output side heat insulation".

[0079] In addition, the optical adhesive layer 5 in this example of the present application maintains adhesive strength within the temperature range of -40°C to +85°C, avoiding interface peeling due to thermal expansion and contraction, and ensuring long-term thermal conduction reliability.

[0080] By optimizing the thermal conductivity and thickness parameters of the optical adhesive layer 5, this application achieves the following breakthroughs: (1) Improved heat dissipation efficiency: The heat conduction efficiency between the double-layer heat dissipation optical medium layer (the first heat dissipation optical medium layer 3 and the second heat dissipation optical medium layer 9) and the liquid crystal screen 6 is significantly improved, thereby reducing the overall thermal resistance of the image generation unit; (2) Compact structure: The traditional beam expander and diffuser are omitted, shortening the optical path by more than 30%, which greatly reduces the volume of the image generation unit; (3) Enhanced reliability: The stability of the image generation unit in high temperature environments is guaranteed, providing key support for the long-term stable operation of the HUD.

[0081] In this example of the present application, an efficient and reliable thermal management system is constructed through the material selection and thickness control of the optical adhesive layer 5 and the coordinated design with the double-layer heat dissipation optical medium. While simplifying the optical structure of the image generation unit, the performance and life of the image generation unit under high temperature conditions are improved.

[0082] In some examples of the present application, the optical adhesive layer 5 is an optically transparent resin OCR or an optically transparent adhesive OCA.

[0083] Both OCR and OCA have high light transmittance (≥95% in the visible light band 380-700nm), ensuring unimpeded penetration of imaging light from the LCD screen 6 and preventing virtual image brightness degradation caused by light absorption or scattering by the optical adhesive layer 5. The material of the optical adhesive layer 5 has no significant absorption in the near-infrared band (700-1100nm), and works in conjunction with the infrared high-reflection film 7 to avoid interference with thermal management functions.

[0084] The OCR and OCA maintain bonding strength within a wide temperature range of -40°C to +85°C, preventing the optical adhesive layer 5 from peeling off or the LCD screen 6 from debonding from the adjacent heat dissipation medium layer due to thermal expansion and contraction, thereby ensuring a smooth long-term heat conduction path.

[0085] This application constructs an efficient heat conduction path while ensuring optical performance and bonding strength through material selection and parameter optimization of OCR and OCA adhesive layers.

[0086] In some examples of the present application, the first heat dissipation optical medium layer 3 and the second heat dissipation optical medium layer 9 are both made of thermally conductive glass or thermally conductive plastic.

[0087] Thermally conductive glass: With a thermal conductivity of ≥2W / mK (much higher than the 1W / mK of ordinary glass), it leverages the glass's inherent high thermal conductivity to rapidly conduct heat laterally. Thermally conductive glass offers high material stability and high-temperature resistance (it can withstand short-term impacts exceeding 200°C), and boasts an optical transmittance of ≥90%, fully meeting HUD imaging requirements.

[0088] Thermally conductive plastics: These can be filled with thermally conductive fillers such as boron nitride and graphite to achieve heat conduction. Their advantage is that they are over 40% lighter than glass, making them suitable for applications requiring minimal weight.

[0089] The thickness of the first heat dissipation optical medium layer 3 is, for example, 1 mm to 3 mm.

[0090] Optionally, the thickness of the first heat dissipating optical medium layer 3 is 2 mm.

[0091] The thickness of the second heat dissipating optical medium layer 9 is, for example, 3 mm to 5 mm.

[0092] Optionally, the thickness of the second heat dissipating optical medium layer 9 is 4 mm.

[0093] In some examples of the present application, the optical microstructure layer 4 is a single-sided structure, and its microstructure surface faces the illumination light source 1; the optical microstructure layer 4 includes a plurality of microstructure units, wherein: each of the microstructure units is a free-form convex mirror, and the aperture size of each microstructure unit is 20μm~30μm.

[0094] The microstructure surface faces the illumination light source 1 , which can maximize the capture and regulation of the collimated light beam and reduce back reflection loss.

[0095] The microstructure units are free-form convex mirrors, each with an aperture of 20μm to 30μm. This convex curvature enables precise beam expansion, matching the HUD optical path requirements. The microstructure array increases the surface area of ​​the first heat-dissipating optical medium layer 3 by 30% to 50%, significantly improving thermal radiation efficiency. The 20μm to 30μm aperture strikes a balance between process feasibility (nanoimprinting) and optical performance, avoiding diffraction effects caused by undersized components or uneven diffusion caused by oversized components.

[0096] In summary, the design in this application eliminates the need for traditional beam expanders by integrating microstructures directly onto the surface of the heat-dissipating optical medium layer, reducing optical path loss by over 8%. The increased heat radiation area of ​​the microstructured surface reduces the temperature rise caused by the LED backlight. Furthermore, the size range of the microstructure units is well-suited for nanoimprinting / etching processes, achieving a yield of over 95%.

[0097] In some examples of the present application, the plurality of free-form convex mirrors in the optical microstructure layer 4 are arranged in an array or randomly; The optical etendue of each free-form convex mirror is determined by the following relationship: The horizontal expansion H is: H = 2arcsin [EB (H) × sin FOV (H) / 2] / Display (H)]; The longitudinal expansion V is: V = 2arcsin [EB (V) × sin FOV (V) / 2] / Display (V)]; Where: EB(H) and EB(V) represent the eye box sizes in the horizontal and vertical directions, respectively; FOV (H) and FOV (V) represents the field of view in the horizontal and vertical directions, respectively; Display (H) and Display (V) represents the horizontal size and vertical size of the display screen of the liquid crystal screen 6 respectively.

[0098] According to the example provided in this application, the horizontal / vertical expansion (H / V) is calculated through the eye box size (EB), field of view (FOV) and display size (Display) to ensure that the beam diffusion accurately matches the requirements of the head-up display device (HUD); the arcsin function in the formula constrains the physically achievable range of the diffusion angle to avoid over-design.

[0099] By customizing the horizontal expansion H and vertical expansion V, the uniformity of the virtual image's coverage of the eyebox is improved. The same PGU platform can adapt to the EB / FOV requirements of different vehicle models by adjusting microstructure parameters.

[0100] In some examples of the present application, the optical microstructure layer 4 is transferred to the light-incident side surface of the first heat dissipation optical medium layer 3 by nanoimprinting, or the optical microstructure layer 4 is formed on the light-incident side surface of the first heat dissipation optical medium layer 3 by etching.

[0101] In this example of the present application, two methods for forming the optical microstructure layer 4 are provided.

[0102] If the microstructure is a regular array (such as MLA), nanoimprinting can be used to reduce costs.

[0103] If customized microstructures are required (such as free-form surfaces that precisely match the HUD optical path), an etching process can be used.

[0104] The present application forms an optical microstructure layer 4 on one surface of the first heat-dissipating optical medium layer 3 through a nanoimprint or etching process, achieving the triple benefits of improved optical efficiency, optimized thermal management, and simplified structure, providing key technical support for the miniaturization, high reliability, and low cost of vehicle-mounted HUD.

[0105] In some examples of the present application, the infrared high-reflection film 7 and the anti-glare film 8 are deposited on the opposite side surfaces of the second heat dissipation optical medium layer 9 by evaporation or magnetron sputtering.

[0106] Evaporation involves heating a film material (such as silver or indium tin oxide (ITO)) at high temperatures to vaporize it, then depositing it onto the substrate surface to form a dense film. This method is suitable for applications requiring high film uniformity. For example, the infrared high-reflective film 7 in this application can be formed on the surface of the second heat-dissipating optical medium layer 9 using evaporation.

[0107] Magnetron sputtering uses plasma to bombard a target material (such as silicon dioxide or silicon nitride), sputtering atoms onto the substrate surface to form a highly adherent film. Magnetron sputtering is suitable for complex film designs. For example, the anti-glare film 8 in this application can be formed on the surface of the second heat-dissipating optical medium layer 9 using magnetron sputtering.

[0108] In the present application, the second heat dissipating optical medium layer 9 is, for example, thermally conductive glass, whose thermal conductivity is ≥2W / mK and whose thickness can be designed to be 4mm. It delays heat transfer through its own specific heat capacity and provides a flat, heat-resistant base for forming a coating.

[0109] In some examples of the present application, the display component is tilted relative to the collimating lens array 2 to match the rear-end optical path imaging requirements; the liquid crystal screen 6 in the display component is a TFT LCD screen.

[0110] The display assembly (TFT LCD screen 6) forms a tilt angle θ relative to the collimating lens array 2. This angle precisely aligns the imaging beam with the rear-end HUD amplified optical path (e.g., the windshield reflection path). The specific value of the tilt angle θ is customized based on parameters such as the vehicle's windshield curvature and the driver's seat height, and is not limited in this application.

[0111] In some examples of the present application, the lighting source 1 adopts a partitioned controllable LED array structure, which is configured to independently control the brightness of each partitioned LED, thereby providing lighting light with a local dimming function.

[0112] In the example provided herein, the illumination source 1 can employ a zoned, controllable LED array structure. The core of this structure is to independently control the brightness of each zoned LED to achieve local dimming. This design significantly improves the HUD system's imaging contrast, backlight efficiency, and heat dissipation performance through dynamic light intensity regulation and thermal management optimization.

[0113] Zone dimming enables virtual images to maintain high contrast and clarity in complex environments such as strong light and low light, meeting the high reliability requirements for information display.

[0114] In some examples of the present application, the image generating unit further includes a fixing bracket 10 , and the illumination light source 1 , the collimating lens array 2 , and the display assembly are all disposed on the fixing bracket 10 .

[0115] The fixing bracket 10 can integrate the illumination light source 1, the collimating lens array 2 and the display assembly into the same frame through an integrated cavity design, thereby facilitating the assembly of the image generation unit in the entire head-up display device or vehicle.

[0116] According to another embodiment of the present application, a head-up display device is provided, which includes: the image generation unit PGU as described above, a reflector group and a windshield of a vehicle; wherein the reflector group reflects the output light of the image generation unit to the windshield to form a virtual image.

[0117] The head-up display device provided in the embodiment of the present application is, for example, a vehicle-mounted head-up display device.

[0118] According to yet another embodiment of the present application, a vehicle is provided, comprising the head-up display device as described above.

[0119] The specific implementation of the head-up display device and vehicle in the embodiments of the present application can refer to the various embodiments of the above-mentioned image generation unit, and therefore at least have all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0120] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0121] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above examples may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. An image generation unit for a head-up display device, characterized in that: The image generating unit includes: An illumination light source (1), for providing illumination light; A collimating lens array (2) for converting the illumination light into a collimated light beam; as well as, Display components, including: LCD screen (6); A first heat dissipation optical medium layer (3) is glued to the back side of the liquid crystal screen (6), and an optical microstructure layer (4) is provided on the light incident side surface thereof, wherein the optical microstructure layer (4) is used to diffuse the collimated light beam into an expanded light beam that matches the amplified light path in the head-up display device; A second heat dissipating optical medium layer (9) is glued to the light-emitting side of the liquid crystal screen (6), and an infrared high-reflection film (7) is provided between the second heat dissipating optical medium layer (9) and the liquid crystal screen (6), wherein the infrared high-reflection film (7) is used to reflect infrared band light to reduce heat input; Wherein, the thermal conductivity of the first heat dissipation optical medium layer (3) and the second heat dissipation optical medium layer (9) are both not less than 2 W / mK.

2. The image generation unit according to claim 1, wherein The light-emitting side surface of the second heat-dissipating optical medium layer (9) is provided with an anti-glare film (8) for suppressing optical ghosting.

3. The image generation unit according to claim 1, wherein The first heat dissipation optical medium layer (3) and the second heat dissipation optical medium layer (9) are respectively bonded to the liquid crystal screen (6) via an optical adhesive layer (5), wherein: the thermal conductivity of the optical adhesive layer (5) is 0.1W / mK~0.3W / mK, and the thickness of the optical adhesive layer (5) is 100μm~400μm.

4. The image generation unit according to claim 3, characterized in that The optical adhesive layer (5) is an optically transparent resin OCR or an optically transparent adhesive OCA.

5. The image generation unit according to claim 1, wherein The first heat dissipation optical medium layer (3) and the second heat dissipation optical medium layer (9) are both made of heat-conducting glass or heat-conducting plastic.

6. The image generation unit according to claim 1, characterized in that The optical microstructure layer (4) is a single-sided structure, and its microstructure surface faces the illumination light source (1); The optical microstructure layer (4) comprises a plurality of microstructure units, wherein each of the microstructure units is a free-form convex mirror, and the aperture size of each microstructure unit is 20 μm to 30 μm.

7. The image generation unit according to claim 6, characterized in that The plurality of free-form convex mirrors in the optical microstructure layer (4) are arranged in an array or randomly; The optical etendue of each free-form convex mirror is determined by the following relationship: The horizontal expansion H is: H = 2arcsin [EB (H) × sin FOV (H) / 2] / Display (H)]; The longitudinal expansion V is: V = 2arcsin [EB (V) × sin FOV (V) / 2] / Display (V)]; Where: EB(H) and EB(V) represent the eye box sizes in the horizontal and vertical directions, respectively; FOV (H) and FOV (V) represents the field of view in the horizontal and vertical directions, respectively; Display (H) and Display (V) respectively represent the horizontal size and vertical size of the display screen of the liquid crystal screen (6).

8. The image generation unit according to claim 1, wherein: The optical microstructure layer (4) is transferred to the light incident side surface of the first heat dissipating optical medium layer (3) by nanoimprinting; or, The optical microstructure layer (4) is formed on the light incident side surface of the first heat dissipation optical medium layer (3) by etching.

9. The image generation unit according to claim 2, wherein: The infrared high-reflection film (7) and the anti-glare film (8) are deposited on the surfaces of the second heat-dissipating optical medium layer (9) on both sides thereof by evaporation or magnetron sputtering.

10. The image generation unit according to claim 1, wherein: The display component is arranged tilted relative to the collimating lens array (2) to match the imaging requirements of the rear-end optical path; The liquid crystal screen (6) in the display component is a TFT LCD liquid crystal screen.

11. The image generation unit according to claim 1, wherein: The lighting light source (1) adopts a partitioned controllable LED array structure, which is configured to be able to independently control the brightness of each partitioned LED, thereby providing lighting light with a local dimming function.

12. The image generation unit according to claim 1, wherein: The image generation unit further comprises a fixed bracket (10), and the illumination light source (1), the collimating lens array (2) and the display assembly are all arranged on the fixed bracket (10).

13. A head-up display device, characterized in that: include: The image generating unit according to any one of claims 1 to 12, and a reflector assembly and a windshield of a vehicle, wherein the reflector assembly reflects the output light of the image generating unit onto the windshield to form a virtual image.

14. A vehicle, characterized in that: include: The head-up display device according to claim 13.

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