Image generation unit, head-up display device, and vehicle

Abstract

Embodiments of the present application provide 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 arranged in sequence along a 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, and a first heat dissipation optical medium layer and a second heat dissipation optical medium layer respectively bonded to the back side and the light emitting side of the liquid crystal screen, wherein: the light entering side surface of the first heat dissipation optical medium layer is provided with an optical microstructure layer for forming expanded beam light matching the magnified light path in the vehicle-mounted head-up display device; an infrared high reflection film is arranged between the liquid crystal screen and the second heat dissipation optical medium layer for reflecting infrared band light to reduce heat input; the thermal conductivity of the first heat dissipation optical medium layer and the second heat dissipation optical medium layer is not less than 2 W / mK.

Description

Technical Field

[0001] This application relates to the field of optical display technology, and more specifically, to an image generation unit, a head-up display device, and a vehicle. Background Technology

[0002] Head-up displays (HUDs) are automotive electronic components that display information on the windshield of a car, greatly facilitating drivers' observation of vehicle instrument information and effectively ensuring driving safety. Their application in the automotive field is becoming increasingly widespread.

[0003] Traditional HUD systems acquire projected images by illuminating an image generation unit, and then reflect these images onto the car's windshield via the magnified optical path inside the head-up display to form a virtual image. In the traditional HUD TFT PGU optical scheme, after the LED array is illuminated by current, the light with a large angle of diffusion is transmitted to a collimating device. This device, for example, uses a biconvex lens to converge the beam, which is then processed sequentially by a beam expander group and a diffuser before being transmitted to the TFT (liquid crystal display). Finally, the beam is imaged by the TFT and transmitted to the back-end HUD optical system. However, this scheme has the following significant drawbacks:

[0004] (1) Overheating problem caused by sunlight backflow: Due to the principle of light reversibility, the internal light path of HUD will converge strong light from outside the vehicle (such as sunlight) to the image generation unit (PGU), forming a high-energy converged light spot, which will cause local overheating of TFT. In extreme cases, it may damage the components. Conventional heat dissipation solutions are difficult to meet the requirements of rapid heat conduction and temperature rise delay.

[0005] (2) Complex optical system: The beam expander group and independent heat dissipation structure result in a large system size. The cumulative light efficiency loss between optical components reaches 8% (calculated based on 4% loss on one side of injection-molded lens). Furthermore, a separate structure needs to be designed for each lens, which increases the overall complexity and manufacturing cost.

[0006] (3) Backlight heat accumulation and thermal radiation attenuation: The heat generated by high-power LED backlight accumulates on the back side of the TFT, affecting the display stability; at the same time, long-term 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

[0007] 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.

[0008] In a first aspect, this application provides an image generation unit for a head-up display device, the image generation unit comprising the following components arranged sequentially along the light transmission direction:

[0009] Light source, used to provide illumination;

[0010] A collimating lens array for converting the illumination light into a collimated beam; and,

[0011] Display components include:

[0012] LCD screen;

[0013] The first heat dissipation optical medium layer is bonded to the back side of the liquid crystal screen, and an optical microstructure layer is provided on its light-incident surface. The optical microstructure layer is used to diffuse the collimated beam into a beam-expanding beam that matches the magnification optical path in the head-up display device.

[0014] The second heat dissipation optical medium layer is bonded to the light-emitting side of the liquid crystal screen, and an infrared high-reflection film is disposed between the liquid crystal screen and the liquid crystal screen. The infrared high-reflection film is used to reflect infrared light to reduce heat input.

[0015] The thermal conductivity of both the first and second heat dissipation optical media layers is not less than 2 W / mK.

[0016] Optionally, an anti-glare film is provided on the light-emitting side surface of the second heat-dissipating optical medium layer to suppress optical ghosting.

[0017] Optionally, the first heat dissipation optical medium layer and the second heat dissipation optical medium layer are respectively bonded to the liquid crystal screen by an optical adhesive layer, 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.

[0018] Optionally, the optical adhesive layer is an optically transparent resin (OCR) or an optically transparent adhesive (OCA).

[0019] Optionally, both the first heat dissipation optical medium layer and the second heat dissipation optical medium layer are made of thermally conductive glass or thermally conductive plastic.

[0020] Optionally, the optical microstructure layer has a single-sided structure, and its microstructure surface faces the illumination source;

[0021] The optical microstructure layer includes multiple microstructure units, wherein each microstructure unit is a freeform convex mirror, and the aperture size of each microstructure unit is 20μm~30μm.

[0022] Optionally, the multiple freeform convex mirrors in the optical microstructure layer are arranged in an array or randomly.

[0023] The optical spread of each of the freeform convex mirrors is determined by the following relationship:

[0024] The lateral expansion H is: H = 2arcsin[EB(H) × sin FOV (H) / 2] / Display (H)];

[0025] The longitudinal expansion V is: V = 2arcsin[EB(V) × sin FOV (V) / 2] / Display (V)];

[0026] Where: EB(H) and EB(V) represent the eye box dimensions in the horizontal and vertical directions, respectively;

[0027] FOV (H) and FOV (V) represents the field of view in the horizontal and vertical directions, respectively;

[0028] Display (H) and Display (V) represent the horizontal and vertical dimensions of the image displayed on the LCD screen, respectively.

[0029] Optionally, the optical microstructure layer is transferred to the light-incident surface of the first heat-dissipating optical medium layer via nanoimprinting; or,

[0030] The optical microstructure layer is formed on the light-incident surface of the first heat-dissipating optical medium layer by etching.

[0031] Optionally, the infrared high-reflectivity film and the anti-glare film are deposited on opposite sides of the second heat dissipation optical medium layer by vapor deposition or magnetron sputtering.

[0032] Optionally, the display component is tilted relative to the collimating lens array to match the imaging requirements of the back-end optical path;

[0033] The liquid crystal screen in the display component is a TFT LCD screen.

[0034] Optionally, the lighting source adopts a zoned controllable LED array structure, which is configured to independently control the brightness of each zone of LEDs, thereby providing lighting light with local dimming function.

[0035] Optionally, the image generation unit further includes a fixed bracket, on which the illumination source, the collimating lens array, and the display component are all disposed.

[0036] Secondly, this application provides a head-up display device, the head-up display device comprising: 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 onto the windshield to form a virtual image.

[0037] Thirdly, this application provides a vehicle, the vehicle comprising:

[0038] The head-up display device as described in the second aspect.

[0039] The beneficial effects of this application are as follows:

[0040] The image generation unit provided in this application embodiment, by setting a first heat-dissipating optical medium layer with an optical microstructure layer, not only forms a beam-expanding 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 sunlight backflow, effectively avoiding local overheating of the LCD screen; at the same time, an infrared high-reflection film is set between the second heat-dissipating optical medium layer and the LCD screen to reflect infrared light and reduce heat input. Combined with the double-layer high thermal conductivity medium (≥2W / mK), it further delays the temperature rise, effectively solving the problems of overheating due to sunlight backflow, insufficient heat dissipation efficiency, and component performance degradation caused by infrared thermal radiation in traditional solutions.

[0041] 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

[0042] 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.

[0043] Figure 1 This is a schematic diagram of the structure of the image generation unit in an embodiment of this application;

[0044] Figure 2 This is a schematic diagram of the structure of a traditional HUD system;

[0045] Figure 3 This is a schematic diagram of the structure of a traditional PGU system.

[0046] Explanation of reference numerals in the attached figures:

[0047] 1. Illumination source; 2. Collimating lens array; 3. First heat dissipation optical medium layer; 4. Optical microstructure layer; 5. Optical adhesive layer; 6. Liquid crystal screen; 7. Infrared high reflectivity film; 8. Anti-glare film; 9. Second heat dissipation optical medium layer; 10. Fixing bracket; 11. Diffuser; 12. First beam expander; 13. Second beam expander; 14. Windshield; 15. Curved mirror; 16. Folding mirror. Detailed Implementation

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] The following description, in conjunction with the accompanying drawings, details an image generation unit, a head-up display device, and a vehicle provided in the embodiments of this application.

[0054] According to one embodiment of this application, an image generation unit is provided for a head-up display device, see [link to relevant documentation]. Figure 1 The image generation unit includes an illumination source 1, a collimating lens array 2, and a display component arranged sequentially along the light transmission direction. The illumination source 1 provides illumination light. The collimating lens array 2 converts the illumination light into a collimated beam. The display component includes a liquid crystal screen 6, a first heat-dissipating optical medium layer 3, and a second heat-dissipating optical medium layer 9. The first heat-dissipating optical medium layer 3 is bonded to the back side of the liquid crystal screen 6, and an optical microstructure layer 4 is disposed on its light-incident surface. The optical microstructure layer 4 is used to diffuse the collimated beam into a beam-expanded beam that matches the magnification optical path within the head-up display device. The second heat-dissipating optical medium layer 9 is bonded to the light-emitting side of the liquid crystal screen 6, and an infrared high-reflectivity film 7 is disposed between it and the liquid crystal screen 6. The infrared high-reflectivity film 7 is used to reflect infrared light to reduce heat input. The thermal conductivity of both the first heat-dissipating optical medium layer 3 and the second heat-dissipating optical medium layer 9 is not less than 2 W / mK.

[0055] The image generation unit (PGU) provided in this application embodiment is specifically designed to address several core problems existing in traditional vehicle HUD devices (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 heat accumulation of backlight LEDs, and performance degradation of optical components caused by infrared thermal radiation. Through the integrated design of a new optical structure and a high-efficiency heat dissipation structure, a significant improvement in overall performance is achieved.

[0056] The image generation unit (PGU) provided in this application embodiment is specifically designed for head-up display devices (HUDs), especially automotive head-up display devices. While ensuring high-brightness virtual image display, it can be well adapted to the limited installation space in vehicles and extend the service life of head-up display devices through the simplification of optical structure and the enhancement of thermal management.

[0057] The main components of the image generation unit provided in the embodiments of this application are described below.

[0058] See Figure 1 The image generation unit provided in this application embodiment includes an illumination source 1.

[0059] In the image generation unit (PGU) provided in this application embodiment, the illumination source 1 is, for example, an array of light-emitting diodes (LEDs). As the source of illumination light, the core function of the illumination source 1 is to provide high-brightness illumination light for the head-up display (HUD) to ensure that the virtual image projected onto the vehicle's windshield has sufficient clarity and contrast to meet the information readability requirements in driving scenarios.

[0060] In terms of power design, the illumination source 1 should balance brightness output and thermal management. While high-power LEDs can improve brightness, traditional solutions suffer from significant backlight heat accumulation, which can lead to localized overheating of the LCD screen or even damage to components with continuous illumination. This application addresses this issue through a novel heat dissipation design, such as a reasonable combination of a dual-layer heat dissipation optical medium layer (a first heat dissipation optical medium layer 3 and a second heat dissipation optical medium layer 9) with an optical microstructure layer 4 and an infrared high-reflectivity film 7. This effectively reduces the risk of backlight heat accumulation to below a safe threshold while ensuring high brightness display.

[0061] See Figure 1 The image generation unit provided in this application embodiment includes a collimating lens array 2, which is located on the light output path of the illumination source 1.

[0062] In the image generation unit (PGU) provided in this application embodiment, the collimating lens array 2 is one of the core optical components. It is responsible for converting the diffused light emitted by the illumination source 1 (such as an LED array) into a parallel collimated beam, which provides basic support for the matching of the subsequent optical path with the HUD magnification optical path.

[0063] See Figure 1 The image generation unit provided in this application embodiment also includes a specially designed display component.

[0064] In the image generation unit (PGU) provided in this application embodiment, the display component serves as the core imaging module, and its design mainly focuses on the double-layer heat dissipation optical structure on both sides of the liquid crystal screen 6. The optical structure design of the display component in this application effectively solves the overheating problem caused by sunlight backflow and backlight heat accumulation in traditional solutions.

[0065] Specifically, the display component uses the liquid crystal screen 6 as its core and forms a projected image by modulating incident light. To address the high-temperature issue, in this embodiment, a first heat-dissipating optical medium layer 3 and a second heat-dissipating optical medium layer 9 are introduced on the back side and light-emitting side of the liquid crystal screen 6, respectively, to construct an active heat dissipation system.

[0066] The first heat-dissipating optical medium layer 3 is bonded to the back side of the liquid crystal screen 6, and an optical microstructure layer 4 is integrated on its light-incident surface. This optical microstructure layer 4 can achieve dual technical effects:

[0067] (1) Optical path matching optimization: The collimated beam can be converted into a beam-expanding beam that matches the magnification optical path within the entire head-up display device by using microstructured surfaces (such as freeform convex mirrors), which can replace the multi-stage beam expander group in traditional solutions. This optical design can, for example, shorten the optical path by more than 30% and significantly reduce the overall volume of the image generation unit (PGU).

[0068] (2) Improved heat dissipation efficiency: The surface area of ​​the microstructure on the optical microstructure layer 4 is 40% or even higher than that of the planar glass. Combined with high thermal conductivity materials, such as the thermal conductivity of the two heat dissipation optical media layers ≥2W / mK, the heat generated by the backlight LED and sunlight backflow can be quickly conducted to the entire surface of the first heat dissipation optical media 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 about 60%.

[0069] It should be noted that the surface of the optical microstructure layer 4 is distributed with multiple free-form convex mirror structures. These microstructures form densely distributed curved units through their convex morphology, which effectively increases the surface area of ​​the first heat dissipation optical medium layer 3, thereby significantly improving the heat dissipation efficiency.

[0070] The second heat-dissipating optical medium layer 9 is bonded to the light-emitting side of the liquid crystal screen 6, and an infrared high-reflectivity film 7 is specially provided between the second heat-dissipating optical medium layer 9 and the light-emitting side of the liquid crystal screen 6, forming a thermal protection barrier. This is because the introduction of the infrared high-reflectivity film 7 can block infrared thermal radiation.

[0071] For example, the infrared high reflectivity film 7 has a reflectivity of ≥95% in the near-infrared band (e.g., 700nm~1100nm), effectively blocking non-visible infrared light in 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.

[0072] See Figure 2 In the optical design of a traditional PGU system, a cold light source must be placed between the PGU and the curved mirror 15. The cold light film is placed on... Figure 2 The principle of the folding mirror 16 is to reduce the thermal damage of sunlight to the PGU 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 about 4%-8% light energy loss; (3) The cold light film installation structure needs to be designed separately, which increases the material and assembly costs.

[0073] This application achieves the following technical improvements by directly integrating the infrared high-reflectivity film 7 with infrared filtering function into the second heat dissipation optical medium layer 9 in front of the liquid crystal screen 6:

[0074] Completely removing the traditional cold light film and folding mirror structure reduces the optical path length; the freed-up layout space allows for more flexible HUD adaptation across the vehicle, especially suitable for compact models.

[0075] The infrared high-reflectivity film 7 is directly deposited onto the second heat-dissipating optical medium layer 9, thereby improving thermal reflection efficiency. This avoids the multi-interface light loss of traditional cold light films and can improve the system's light efficiency.

[0076] In addition, compared to Figure 2 The optical architecture shown in the figure also reduces the number of optical components, lowers production costs, and simplifies the assembly process.

[0077] In this application, the second heat-dissipating optical medium layer 9 and the first heat-dissipating optical medium layer 3 cooperate to form a double-layer high thermal conductivity channel for the liquid crystal screen 6. Through the heat conduction of these two heat-dissipating optical medium layers (thermal conductivity ≥ 2 W / mK), the surface temperature rise time of the liquid crystal screen 6 can be extended by more than 2 times, ensuring the long-term reliability of the components.

[0078] See Figure 3 Traditional PGU systems rely on multiple stages of optical components for optical path matching: the liquid crystal screen 6 (e.g., TFT) in this system requires a first beam expander 12, a second beam expander 13, and a diffuser 11 spaced apart to achieve light collimation and beam expansion. This design leads to two major drawbacks:

[0079] (1) Thermal management failure: The heat from sunlight backflow and backlight LEDs accumulates on the surface of the LCD screen. Due to the lack of an effective heat dissipation path, it is easy to cause local overheating and shorten the life of components.

[0080] (2) High system redundancy: The superposition of multiple lens levels makes the optical path long and the volume large, making it difficult to adapt to the compact installation space of the vehicle.

[0081] Traditional PGU system, see Figure 3 This optical design not only increases the complexity of the system structure and manufacturing cost, but also reduces the overall optical efficiency due to the light efficiency loss between multiple lens levels (the loss of a single lens is about 4%).

[0082] This application achieves two core improvements through the integrated design of a double-layer heat dissipation medium layer (i.e., the first heat dissipation optical medium layer 3 and the second heat dissipation optical medium layer 9) with the optical microstructure layer 4 and the infrared high reflectivity film 7:

[0083] (1) Simplified structure: The number of optical components is reduced (such as omitting the beam expander group and the diffuser), which can shorten the optical path by more than 30%, and significantly reduce the system size and weight;

[0084] (2) Heat dissipation optimization: The dual-layer heat dissipation optical medium (thermal conductivity ≥2W / mK) combined with the microstructure heat dissipation design effectively disperses the backlight heat and avoids local overheating. At the same time, the infrared high reflective film 7 blocks more than 95% of the near-infrared heat input, ensuring the long-term reliability of the equipment.

[0085] In short, this application directly eliminates the beam expander group and diffuser by coordinating the collimating lens array 2 with the subsequent optical microstructure layer 4. This design shortens the optical path by more than 30%, significantly reduces the volume of the entire image generation unit, and improves the overall light efficiency by 8% by reducing the number of optical components (calculated based on a 4% loss per side of the injection-molded lens).

[0086] The optical design scheme of the image generation unit provided in this application embodiment solves the problem of overheating due to sunlight backflow. In traditional solutions, strong light from outside the vehicle (such as sunlight) is focused onto the LCD screen 6 through the HUD optical path, forming a high-energy light spot that leads to overheating. In this application embodiment, however, infrared high-reflectivity film 7 reflects infrared light, reducing heat input; at the same time, a double-layer high heat dissipation medium material (thermal conductivity ≥2W / mK) rapidly conducts heat, avoiding localized accumulation. The optical microstructure layer 4 further increases the heat dissipation area and improves thermal radiation efficiency; the three work together to achieve efficient heat dissipation.

[0087] The optical design scheme of the image generation unit provided in this application simplifies the optical system and improves space utilization. Traditional solutions require beam expanders and diffusers to achieve optical path matching, resulting in a bulky PGU system and low optical efficiency (4% loss per side lens). This application directly generates expanded beams through optical microstructure layer 4, eliminating the need for beam expanders and diffusers, shortening the optical path by more than 30%, and making the overall structure more compact, suitable for the limited installation space in vehicles.

[0088] The optical design scheme of the image generation unit provided in this application embodiment can suppress backlight heat accumulation and thermal radiation attenuation. In traditional solutions, the heat generated by high-power LED backlight accumulates on the back side of the LCD screen, affecting display stability; at the same time, infrared thermal radiation causes performance degradation of optical components. In this application embodiment, the high thermal conductivity of the first heat dissipation optical medium layer 3 quickly conducts backlight heat, avoiding accumulation; the infrared high-reflectivity film 7 can reduce the input of infrared light, delay component performance degradation, and extend the service life of the device.

[0089] The optical design scheme of the image generation unit provided in this application embodiment improves optical efficiency and imaging quality. The optical microstructure layer 4 is rationally designed through MLA (microlens array) to customize and match the back-end optical path of the HUD, reducing light efficiency loss.

[0090] This application's embodiments address several core pain points of traditional HUD systems through a novel optical and heat dissipation structural design: overheating due to 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 imaging quality, providing crucial technical support for the miniaturization, high reliability, and long lifespan of automotive HUD devices.

[0091] See some examples in this application. Figure 1 The light-emitting side surface of the second heat dissipation optical medium layer 9 is provided with an anti-glare film 8 to suppress optical ghosting.

[0092] In the example provided in this application, an anti-glare film 8 is added to the light-emitting side surface of the second heat dissipation optical medium layer 9. This design significantly improves the imaging quality of the HUD by suppressing optical ghosting.

[0093] In traditional HUD systems, differences in glass thickness can cause light to reflect multiple times between the vehicle's windshield and the PGU (Image Generation Unit) system, creating a "ghosting" effect. This ghosting reduces the clarity of the virtual image, and may interfere with the driver's reading of instrument information, especially in bright light environments (such as direct sunlight), posing a safety hazard.

[0094] The anti-glare film 8 design proposed in this example can process incident light, and its technical effects are reflected in the following aspects:

[0095] The anti-glare film 8 can evenly disperse the light reflected from the windshield of the vehicle, avoiding the formation of a clear ghosting outline.

[0096] While scattering and reflecting light, the anti-glare film 8 has minimal impact on the transmittance of the main imaging light emitted from the liquid crystal screen 6 (visible light transmittance ≥95%), ensuring that the virtual image display is not affected.

[0097] Combined with the infrared high-reflectivity film 7's blocking of near-infrared light (reflectivity ≥95%), the anti-glare film 8 further reduces the interference of ambient light on imaging and improves readability under strong light.

[0098] In this application, the integrated design of the anti-glare film 8 and the second heat dissipation optical medium layer 9 achieves functional complementarity: the anti-glare film can be directly deposited on the surface of the second heat dissipation optical medium layer 9, without the need for additional optical components, which meets the core objective of "simplified structure" in this application; the second heat dissipation optical medium layer 9 (whose thermal conductivity is ≥2W / mK) can quickly dissipate the trace heat generated by the film layer due to light absorption, avoiding performance degradation of the film layer.

[0099] According to experimental data, the anti-glare film 8 introduced in this example reduces ghosting interference by more than 70%, while ensuring stable operation of the image generation unit in a wide temperature range of -40℃ to +85℃.

[0100] Therefore, the introduction of the anti-glare film 8 significantly improves the imaging clarity of the HUD by suppressing optical ghosting, especially ensuring driving safety in strong light environments. Its synergistic design with the heat dissipation optical medium layer and the infrared high-reflectivity film 7 simplifies the system structure while achieving dual optimization of thermal management and optical performance, providing crucial support for the high-reliability application of automotive HUDs.

[0101] In some examples of this application, 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 by 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.

[0102] In the example provided in this application, the design of the optical adhesive layer 5 has been optimized to achieve efficient heat conduction between the double-layer heat dissipation optical medium layer and the liquid crystal screen 6.

[0103] 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.

[0104] In one specific example of this application, the optical adhesive layer 5 is selected from adhesives with a thermal conductivity of 0.2 W / mK.

[0105] Traditional optical adhesive layers typically have a thermal conductivity of ≤0.05 W / mK. However, in the solution provided in this example, the thermal conductivity design of the optical adhesive layer 5 can improve heat transfer efficiency by 3 to 6 times and significantly reduce thermal conduction resistance.

[0106] Optionally, the thickness of the optical adhesive layer 5 is controlled between 100μm and 400μm.

[0107] In one specific example of this application, the thickness of the optical adhesive layer 5 is 200 μm.

[0108] Traditional optical adhesive layers typically have a thickness of ≥500μm. However, in the solution provided in this example, the thickness design of the optical adhesive layer 5, combined with the thermal conductivity design, can reduce 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.

[0109] The back-side heat dissipation of the LCD screen 6 (with a first heat dissipation optical medium layer 3 on the back side) absorbs the heat generated by the backlight LEDs and sunlight backflow, and conducts it quickly laterally through the first heat dissipation optical medium material (thermal conductivity ≥2W / mK) to avoid local overheating. It should be noted that the lateral conduction here means that the heat can diffuse on the surface of the heat dissipation medium layer.

[0110] The light-emitting side of the LCD screen 6 is heat-insulated (a second heat-dissipating optical medium layer 9 is provided on the light-emitting side): more than 95% of near-infrared heat is reflected by the infrared high-reflection film 7, reducing the input of external heat.

[0111] The heat transfer function of the optical adhesive layer 5 is as an intermediate channel, which rapidly diffuses the local hot spot heat on the surface of the liquid crystal screen 6 to the entire heat dissipation medium layer, forming a closed-loop heat dissipation path of "back side heat absorption - adhesive layer heat transfer - light-emitting side heat insulation".

[0112] In addition, the optical adhesive layer 5 in this example maintains its adhesive strength within the range of -40°C to +85°C, avoiding interface peeling due to thermal expansion and contraction, and ensuring long-term thermal conductivity reliability.

[0113] By optimizing the thermal conductivity and thickness parameters of the optical adhesive layer 5, this application has achieved the following breakthroughs:

[0114] (1) Improved heat dissipation efficiency: The heat conduction efficiency between the dual heat dissipation optical media layer (the first heat dissipation optical media layer 3 and the second heat dissipation optical media layer 9) and the liquid crystal screen 6 is significantly improved, reducing the overall thermal resistance of the image generation unit;

[0115] (2) Compact structure: The traditional beam expander group and diffuser are omitted, and the optical path is shortened by more than 30%, which greatly reduces the size of the image generation unit;

[0116] (3) Enhanced reliability: The stability of the image generation unit under high temperature environment is guaranteed, providing key support for the long-term stable operation of HUD.

[0117] In this example of the application, an efficient and reliable thermal management system is constructed through the selection of materials and thickness control of the optical adhesive layer 5 and its collaborative design with the double-layer heat dissipation optical medium. This simplifies the optical structure of the image generation unit while improving the performance and lifespan of the image generation unit under high-temperature conditions.

[0118] In some examples of this application, the optical adhesive layer 5 is an optically transparent resin OCR or an optically transparent adhesive OCA.

[0119] Both OCR and OCA have high light transmittance (≥95% transmittance in the visible light band 380-700nm), ensuring that the imaging light of the liquid crystal screen 6 passes through without loss, avoiding the attenuation of virtual image brightness due to 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-reflectivity film 7 to avoid interfering with the thermal management function.

[0120] OCR and OCA maintain their bonding strength within a wide temperature range of -40℃ to +85℃, preventing the optical adhesive layer 5 from peeling off or the liquid crystal screen 6 from delaminating with the adjacent heat dissipation medium layer due to thermal expansion and contraction, thus ensuring a smooth heat conduction path over the long term.

[0121] This application constructs an efficient heat conduction path by selecting and optimizing the materials and parameters of the OCR and OCA adhesive layers, while ensuring optical performance and bonding strength.

[0122] In some examples of this application, both the first heat dissipation optical medium layer 3 and the second heat dissipation optical medium layer 9 are made of thermally conductive glass or thermally conductive plastic.

[0123] Thermally conductive glass: Its thermal conductivity is ≥2W / mK (far higher than the 1W / mK of ordinary glass), which can quickly conduct heat laterally by utilizing the high thermal conductivity of the glass itself. The thermally conductive glass material has strong stability, high temperature resistance (can withstand short-term impact above 200℃), and optical transmittance ≥90%, which can fully meet the HUD imaging requirements.

[0124] Thermally conductive plastics: Heat conduction can be achieved by filling them with thermally conductive fillers such as boron nitride and graphite. Their advantage lies in being more than 40% lighter than glass, making them suitable for applications with high lightweight requirements.

[0125] The thickness of the first heat dissipation optical medium layer 3 is, for example, 1 mm to 3 mm.

[0126] Optionally, the thickness of the first heat dissipation optical medium layer 3 is 2 mm.

[0127] The thickness of the second heat dissipation optical medium layer 9 is, for example, 3mm to 5mm.

[0128] Optionally, the thickness of the second heat dissipation optical medium layer 9 is 4 mm.

[0129] In some examples of this application, the optical microstructure layer 4 is a single-sided structure, and its microstructure surface faces the illumination source 1; the optical microstructure layer 4 includes multiple microstructure units, wherein: each microstructure unit is a freeform convex mirror, and the aperture size of each microstructure unit is 20μm~30μm.

[0130] The microstructure surface faces the illumination source 1, which can maximize the capture and control of the collimated beam and reduce back reflection loss.

[0131] The microstructure unit is a freeform convex mirror, with each freeform convex mirror designed with an aperture of 20μm to 30μm. Precise beam expansion is achieved through the convex curvature, matching the optical path requirements of the HUD. 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 fabrication feasibility (nanoimprint processing) and optical performance, avoiding diffraction effects caused by excessively small sizes or diffusion unevenness caused by excessively large sizes.

[0132] In summary, the design in this application, by directly integrating the microstructure onto the surface of the heat-dissipating optical medium layer, eliminates the need for traditional beam expanders, reducing optical path loss by more than 8%. The increased heat radiation area on the microstructure surface reduces the temperature rise caused by LED backlighting. Furthermore, the size range of the microstructure units is compatible with nanoimprint / etching processes, achieving a yield rate of over 95%.

[0133] In some examples of this application, the multiple freeform convex mirrors in the optical microstructure layer 4 are arranged in an array or randomly.

[0134] The optical spread of each of the freeform convex mirrors is determined by the following relationship:

[0135] The lateral expansion H is: H = 2arcsin[EB(H) × sin FOV (H) / 2] / Display (H)];

[0136] The longitudinal expansion V is: V = 2arcsin[EB(V) × sin FOV(V) / 2] / Display (V)];

[0137] Where: EB(H) and EB(V) represent the eye box dimensions in the horizontal and vertical directions, respectively;

[0138] FOV (H) and FOV (V) represents the field of view in the horizontal and vertical directions, respectively;

[0139] Display (H) and Display (V) represent the horizontal and vertical dimensions of the image displayed on the LCD screen 6, respectively.

[0140] According to the example provided in this application, the horizontal / vertical spread (H / V) is calculated using the eyebox size (EB), field of view (FOV), and display size to ensure that the beam spread is precisely matched to the head-up display (HUD) requirements; the arcsin function in the formula constrains the physically achievable range of the spread angle, avoiding over-design.

[0141] By customizing the lateral expansion H and longitudinal expansion V, the uniformity of the virtual image covering the eyebox area is improved. The same PGU platform can be adapted to the EB / FOV requirements of different vehicle models by adjusting the microstructure parameters.

[0142] In some examples of this application, the optical microstructure layer 4 is transferred to the light-incident surface of the first heat-dissipating optical medium layer 3 by nanoimprinting, or the optical microstructure layer 4 is formed on the light-incident surface of the first heat-dissipating optical medium layer 3 by etching.

[0143] This application provides two methods for forming the optical microstructure layer 4 in this example.

[0144] If the microstructure is a regular array (such as MLA), nanoimprinting can be used to reduce costs.

[0145] If customized microstructures are required (such as freeform surfaces that precisely match the HUD optical path), etching processes can be used.

[0146] This application forms an optical microstructure layer 4 on one surface of the first heat dissipation optical medium layer 3 through nanoimprinting or etching processes, achieving a triple benefit of improved optical efficiency, optimized thermal management, and simplified structure, providing key technical support for the miniaturization, high reliability, and low cost of vehicle HUDs.

[0147] In some examples of this application, the infrared high reflectivity film 7 and the anti-glare film 8 are deposited on opposite sides of the second heat dissipation optical medium layer 9 by vapor deposition or magnetron sputtering.

[0148] Evaporation deposition involves heating a film material (such as silver or indium tin oxide, ITO) at high temperature to vaporize it, and then depositing it onto the surface of a substrate to form a dense thin film. This method is suitable for applications requiring high uniformity of the film layer, such as the infrared high-reflectivity film 7 in this application, which can be formed on the surface of the second heat dissipation optical medium layer 9 using evaporation deposition.

[0149] Magnetron sputtering utilizes plasma to bombard a target material (such as silicon dioxide or silicon nitride), sputtering atoms onto the substrate surface to form a highly adhesive film layer. Magnetron sputtering is suitable for complex film system designs; for example, the anti-glare film 8 in this application can be formed on the surface of the second heat dissipation optical medium layer 9 using magnetron sputtering.

[0150] In this application, the second heat dissipation optical medium layer 9 is, for example, thermally conductive glass with a thermal conductivity ≥2W / mK and a thickness of 4mm. It delays heat transfer through its own specific heat capacity and provides a flat and heat-resistant substrate for the formation of the coating.

[0151] In some examples of this application, the display component is tilted relative to the collimating lens array 2 to match the imaging requirements of the back-end optical path; the liquid crystal screen 6 in the display component is a TFT LCD liquid crystal screen.

[0152] The display component (TFT LCD screen 6) is tilted at an angle θ relative to the collimating lens array 2. Its function is to precisely match the imaging beam with the back-end HUD magnification optical path (such as the windshield reflection path). The specific value of the tilt angle θ is customized according to parameters such as the windshield curvature of the vehicle model and the driver's seating position height, and this application does not impose any restrictions on it.

[0153] In some examples of this application, the lighting source 1 adopts a zoned controllable LED array structure, which is configured to independently control the brightness of each zone of LEDs, thereby providing lighting light with local dimming function.

[0154] In the example provided in this application, the lighting source 1 can, for example, adopt a zoned controllable LED array structure. Its core is to achieve local dimming by independently controlling the brightness of each zone's LEDs. This design significantly improves the imaging contrast, backlight efficiency, and heat dissipation performance of the HUD system through dynamic light intensity adjustment and thermal management optimization.

[0155] Local dimming ensures that the virtual image maintains high contrast and clarity in complex environments such as strong light and low light, meeting the high reliability requirements for information display.

[0156] In some examples of this application, the image generation unit further includes a fixed bracket 10, on which the illumination source 1, the collimating lens array 2, and the display component are all disposed.

[0157] The fixed bracket 10, through its integrated cavity design, can integrate the illumination source 1, collimating lens array 2, and display components into the same frame, facilitating the assembly of the image generation unit in the entire head-up display device or vehicle.

[0158] According to another embodiment of this application, a head-up display device is provided, the head-up display device comprising: an 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 onto the windshield to form a virtual image.

[0159] The head-up display device provided in this application embodiment is, for example, a vehicle-mounted head-up display device.

[0160] According to yet another embodiment of this application, a vehicle is provided that includes a head-up display device as described above.

[0161] The specific implementation of the head-up display device and vehicle in this application can refer to the various embodiments of the image generation unit described above. Therefore, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0162] 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.

[0163] 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. An image generation unit for a head-up display device, characterized in that, The image generation unit comprises the following components arranged sequentially along the light transmission direction: Light source (1), used to provide lighting light; A collimating lens array (2) is used to convert the illumination light into a collimated beam; as well as, Display components include: LCD screen (6); The first heat dissipation optical medium layer (3) is bonded to the back side of the liquid crystal screen (6), and an optical microstructure layer (4) is provided on its light-incident surface. The optical microstructure layer (4) is used to diffuse the collimated beam into a beam-expanding beam that matches the magnification optical path in the head-up display device. The second heat dissipation optical medium layer (9) is bonded to the light-emitting side of the liquid crystal screen (6), and an infrared high reflectivity film (7) is disposed between it and the liquid crystal screen (6). The infrared high reflectivity film (7) is used to reflect infrared light to reduce heat input. The thermal conductivity of both the first heat dissipation optical medium layer (3) and the second heat dissipation optical medium layer (9) is not less than 2W / mK. An anti-glare film (8) is provided on the light-emitting side surface of the second heat-dissipating optical medium layer (9) to suppress optical ghosting; 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) through an optical adhesive layer (5), wherein: the thermal conductivity of the optical adhesive layer (5) is 0.1W / mK to 0.3W / mK, and the thickness of the optical adhesive layer (5) is 100μm to 400μm; The optical microstructure layer (4) is a single-sided structure, and its microstructure surface faces the illumination source (1); The optical microstructure layer (4) includes multiple microstructure units, wherein: each microstructure unit is a freeform convex mirror, and the aperture size of each microstructure unit is 20μm to 30μm; The multiple free-form convex mirrors in the optical microstructure layer (4) are arranged in an array or randomly. The optical spread of each of the freeform convex mirrors is determined by the following relationship: The lateral expansion H is: H = 2arcsin[EB(H)×sinFOV(H) / 2] / Display(H)]; The longitudinal expansion V is: V = 2arcsin[EB(V)×sinFOV(V) / 2] / Display(V)]; Where: EB(H) and EB(V) represent the eye box dimensions in the horizontal and vertical directions, respectively; FOV(H) and FOV(V) represent the field of view angles in the horizontal and vertical directions, respectively; Display(H) and Display(V) represent the horizontal and vertical dimensions of the image displayed on the LCD screen (6), respectively.

2. The image generation unit according to claim 1, characterized in that, The optical adhesive layer (5) is an optically transparent resin OCR or an optically transparent adhesive OCA.

3. The image generation unit according to claim 1, characterized in that, Both the first heat dissipation optical medium layer (3) and the second heat dissipation optical medium layer (9) are made of thermally conductive glass or thermally conductive plastic.

4. The image generation unit according to claim 1, characterized in that, The optical microstructure layer (4) is transferred to the light-incident surface of the first heat-dissipating optical medium layer (3) by nanoimprinting; or, The optical microstructure layer (4) is formed on the light-incident surface of the first heat-dissipating optical medium layer (3) by etching.

5. The image generation unit according to claim 1, characterized in that, The infrared high reflectivity film (7) and the anti-glare film (8) are deposited on opposite sides of the second heat dissipation optical medium layer (9) by vapor deposition or magnetron sputtering.

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

7. The image generation unit according to claim 1, characterized in that, The lighting source (1) adopts a zoned controllable LED array structure, which is configured to independently control the brightness of each zone of LEDs, thereby providing lighting light with local dimming function.

8. The image generation unit according to claim 1, characterized in that, The image generation unit further includes a fixed bracket (10), and the illumination source (1), the collimating lens array (2) and the display component are all disposed on the fixed bracket (10).

9. A head-up display device, characterized in that, include: The image generating unit according to any one of claims 1 to 8, the reflector group and the windshield of the vehicle, wherein the reflector group reflects the output light of the image generating unit onto the windshield to form a virtual image.

10. A vehicle, characterized in that, include: The head-up display device as described in claim 9.

Images