Optically optimized, rotation-free curved mirror monocular box ar-hud optical system, ray path optimization method and application

Abstract

This invention discloses an optically optimized, non-rotating curved mirror single-lens AR-HUD optical path system. The system includes an image source, a primary mirror, a secondary mirror, and a windshield. Light rays from the image source pass through the primary mirror, secondary mirror, and windshield to create a virtual image in front of the windshield, which is observed at the virtual image viewing position represented by the eyepiece. The secondary mirror is fixedly mounted on a support bracket of the AR-HUD optical path system. The system utilizes a free-form surface design based on multiple ray tracing simulations and optimizes the surface coating using a multi-wavelength optimization method. This invention also discloses a large-size single-lens box ray path optimization method with broad application value.

Description

Technical Field

[0001] This invention belongs to the field of vehicle head-up display technology, and relates to an optically optimized, non-rotating curved mirror monocular AR-HUD optical path system, a light path optimization method, and its application. Background Technology

[0002] Head-up display (HUD) systems, as an important component of human-machine interaction solutions, are crucial hardware for the future realization of intelligent and connected vehicles and human-machine interaction. By utilizing the principle of optical reflection, they project system information such as navigation, vehicle speed, fuel pressure, tire pressure, and Bluetooth phone connectivity onto the windshield, allowing drivers to concentrate on driving and thus improving driving safety.

[0003] Currently, head-up display (HUD) technology is widely used in the automotive industry. Traditional HUD systems on the market typically employ a three-eye box design to accommodate users of different heights. This design requires a complex mechanical structure to adjust the position of the reflectors. In existing technology, a typical three-eye box HUD system uses a motor-driven mechanism to rotate and adjust the curved mirror, moving the virtual image height to adapt to different heights. However, existing three-eye box HUD systems have complex mechanical structures, high maintenance costs, and their reliability and durability may suffer over long-term use, resulting in noise or vibration that affects usability. Chinese patent application CN112255788A also proposes a fixed secondary reflector, reducing the complexity of the mechanical structure, thereby reducing the overall system weight and cost, enhancing system reliability and durability, reducing the impact on system stability and accuracy, reducing noise during rotation and adjustment, and avoiding damage to the rotating structure. However, the existing Chinese patent application CN112255788A mainly achieves image adaptation to different eye box positions by adjusting the display area of ​​the image source. This solution is prone to image clarity loss and has limitations in field of view and optical performance, thus limiting its applicability. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an optically optimized, non-rotating curved mirror monocular AR-HUD optical path system, which aims to improve and optimize the HUD display effect by optimizing the mirror design of the secondary reflector.

[0005] This invention provides an optically optimized, non-rotating curved mirror single-eye AR-HUD optical path system, the optical path system comprising: an image source, a primary reflector, a secondary reflector, and a windshield; the light generated by the image source passes through the primary reflector, the secondary reflector, and the windshield to generate a virtual image in front of the windshield, which is observed by the human eye at the observation position indicated by the eyebox;

[0006] The image source generates light rays to display the image. The light rays pass through a primary reflector and a secondary reflector in sequence, and are then projected onto the windshield to form a virtual image.

[0007] The primary reflector receives light emitted from the image source and reflects it to the secondary reflector;

[0008] The secondary reflector reflects the light transmitted from the primary reflector and projects it onto the windshield to form a virtual image;

[0009] The windshield serves as a projection medium for virtual images, projecting the generated virtual image into the user's line of sight through the reflection of light.

[0010] In this invention, the fixed position of the secondary reflector should be precisely positioned according to the optical path design. The secondary reflector is typically fixed to the support bracket of the AR-HUD system to maintain stability during use and prevent displacement or tilting due to vibration or external environmental influences. The specific position of the secondary reflector is determined through optical tracking calculations to ensure that the light transmitted from the secondary reflector is accurately reflected onto the windshield and forms a virtual image.

[0011] By optimizing the curved surface and surface coating of the secondary reflector, the resulting virtual image has high clarity.

[0012] Freeform Surface Optimization: The secondary mirror features a freeform surface design, which reduces aberrations and distortions in the optical system. Through precise ray tracing simulation, the surface shape is optimized to reduce spherical aberration, astigmatism, and distortion. The curvature of the secondary mirror is optimized to ensure that light passing through the primary mirror generates a clear virtual image on the windshield, suitable for a wide range of viewing angles.

[0013] Multi-wavelength optimization: To ensure that the virtual image has the same clarity under different wavelengths of light, the surface coating of the secondary mirror is optimized for multiple wavelengths to ensure its reflectivity consistency in the visible light band, and to ensure high reflectivity and low dispersion in the visible light range of 400-700nm, ultimately improving the clarity and color accuracy of the virtual image.

[0014] The distance between the virtual image and the position where the human eye observes the virtual image (i.e., the position of the eye box) is 7.5-10m, and the size is 54 inches; the eye box is a monocular eye box, and the eye box range is 130×100mm.

[0015] The position of the eye box is also the position of the aperture of the AR-HUD system. The aperture has a size of 130×50mm, ensuring that the user can clearly see the virtual image within the 130×100mm eye box range.

[0016] The image source includes LCOS optical engines, DLP optical engines, etc. LCOS optical engines have a resolution of 1920*1280, while DLP optical engines have resolutions of 800*480, 1358*566 / 1152*576, etc., depending on the model. The color gamut should cover at least 75% of the NTSC standard, preferably above 95%, to ensure rich and realistic color reproduction of the virtual image. The mounting base of the image source uses a highly thermally conductive material for passive heat dissipation; specifically, the thermal conductivity of the mounting base is not less than 200 W / (m·K), preferably aluminum alloy (thermal conductivity of 205 W / (m·K)) or copper (thermal conductivity of 400 W / (m·K)). These materials effectively dissipate the heat generated during image source operation, ensuring system stability and long-term performance.

[0017] The primary reflector adopts an aspherical or free-form mirror shape, and its surface is coated with one or more anti-reflective coatings, with a curvature of approximately 0.0011563.

[0018] The secondary reflector adopts an aspherical or freeform mirror shape.

[0019] The image source emission angle is 15°-20°; and / or,

[0020] The curvature of the primary reflector is 0.0011563, the incident angle of light is 20°-30°, and the reflection angle is 22°; and / or,

[0021] The secondary reflector has a tilt angle of 10°-15°, a radius of curvature of 40-80mm, and an incident angle of light of 15°-30°; and / or,

[0022] The windshield is tilted at an angle of 20°-30°.

[0023] The present invention also provides a method for optimizing the light path of a large-size monocular box, the optimization method including light propagation path optimization and optical imaging quality optimization;

[0024] The light propagation path optimization includes optimizing the light propagation path through optical tracing calculations and simulations;

[0025] The optical imaging quality optimization includes mirror surface optimization, aberration and distortion control, and optical performance evaluation.

[0026] The optimization of the light propagation path includes the following steps:

[0027] Step 1: Emit and track multiple light rays, and record the position and angle of the light rays on different optical surfaces;

[0028] Step 2: Perform ray tracing at multiple sampling points on the eye box to simulate the light path from different user perspectives and determine whether the light can eventually enter the user's pupil to form a clear virtual image.

[0029] In optical imaging quality optimization, the mirror surface optimization involves optimizing the design of the mirror surface, adjusting the radius of curvature and surface shape, and reducing optical aberrations and distortions.

[0030] The aberration and distortion control records the aberrations and distortions of light after passing through the optical elements. By adjusting the position and angle of the reflector and the windshield, the overall optical performance is optimized to ensure that light can be focused into the user's pupil at every position in the eye box.

[0031] The optical performance evaluation assesses the optical performance at different sampling points within the eye box and continuously adjusts the system parameters based on the evaluation results to ensure optimal optical performance across the entire eye box area.

[0032] This invention also provides the application of the above-mentioned optical path system or optical path optimization method in the design of vehicle HUD structure and optical path.

[0033] This invention addresses the shortcomings and deficiencies of existing technologies by proposing an optically optimized, non-rotating curved mirror monocular AR-HUD optical path system, aiming to solve these problems through the following methods:

[0034] By designing a single-eye box AR-HUD system, there is no need for a complex motor drive mechanism to adjust the height of the reflector, thereby reducing the mechanical complexity and weight of the system.

[0035] The system is designed so that users can clearly see the virtual image within the 130*100mm eye box area, eliminating the need to move the virtual image to accommodate users of different heights.

[0036] 1. Optimized design of optical components:

[0037] The primary and secondary reflectors in this invention employ specially designed aspherical and freeform lenses. These lenses are precisely calculated to optimize the light path, ensuring that light from the image source to the windshield and then to the user's eye produces a clear virtual image at any point within the eye box. The design of these curved lenses is based on advanced optical simulations and real-world test data to minimize aberrations and distortion.

[0038] 2. Precise adjustment of optical path length and angle:

[0039] The length and angle of the optical path in the system are specially designed to ensure that light is evenly distributed across the upper, middle, and lower parts of the eye box before entering the user's eyes. This design pays special attention to light coverage at different viewing angles, thus adapting to users of different heights.

[0040] 3. Fixing and configuring the reflector:

[0041] Unlike traditional dynamically adjustable reflectors, the secondary reflector in the optical path system of this invention is fixed in place. Its design and placement are rigorously calculated to ensure that light can uniformly cover the entire eye box area without the need for physical adjustments. This has been verified through actual optical testing and user experience testing.

[0042] 4. Material selection:

[0043] All optical components are made of high-transmittance (transmittance greater than 90%) and low-dispersion materials (dispersion coefficient less than 0.01) to ensure image brightness and clarity while reducing light loss and color difference caused by materials.

[0044] The optical path system of this invention improves the mechanical stability and optical performance of the system by eliminating the motor drive mechanism, while reducing the overall cost.

[0045] Differences from existing technologies:

[0046] 1. Fixed aspherical or freeform surface reflector design:

[0047] In CN112255788A, although the second reflector is also a fixed design, its image adjustment is mainly achieved by adjusting the display area of ​​the image source to adapt to different eye box positions. However, this invention, through optical tracking and optimized design, allows the light path to still cover the entire eye box area without a flipping mechanism. Specifically, this invention employs a more complex optical design, combining freeform or aspherical mirrors to more precisely control the direction of light propagation, thereby obtaining a clear virtual image at every position within the eye box.

[0048] 2. Optical path optimization and the special shape of the secondary mirror:

[0049] Unlike the fixed reflector in CN112255788A, the secondary reflector of this invention is not only fixed, but also, through its unique mirror shape design, ensures that light, after passing through the secondary reflector, can uniformly cover the entire area of ​​the eye box. This design simplifies the complexity of the optical system and reduces overlap and distortion of light at different eye box positions.

[0050] The advantages of this design in the present invention include, but are not limited to, the following:

[0051] 1. Enhanced optical performance:

[0052] This invention ensures stable and clear optical performance at each eyepiece position through meticulous curved surface design and optical optimization of the secondary reflector. This means that regardless of the user's position within the eyepiece, they can view the virtual image in high quality without relying on adjustments to the display image source to adapt to different positions, as in CN112255788A.

[0053] 2. Simplify design and reduce costs:

[0054] While CN112255788A simplifies the design by eliminating the mirror flipping mechanism, this invention further optimizes the optical system, eliminating the reliance on display image source adjustment and reducing system complexity and subsequent maintenance costs. Therefore, this invention not only offers advantages in manufacturing costs but also demonstrates significant savings in subsequent use and maintenance costs.

[0055] The optical path system of this invention has significant effects, improving system reliability and durability while maintaining high-quality display effects, and adapting to a wide range of user needs.

[0056] The beneficial effects of the present invention include: the present invention is significantly superior to the prior art in several aspects, specifically in the following aspects:

[0057] 1. Optimization of optical design:

[0058] The monocular optical design adapts to users of different heights: This invention utilizes a large-size monocular box with a freeform or aspherical mirror design through precise optical optimization, eliminating the need for motor-driven adjustment of the reflector position to accommodate users of varying heights. By optimizing the light propagation path, it ensures that all users can clearly see the virtual image within the large 130×100mm box area. This design achieves consistency and clarity of the virtual image across multiple angles and fields of view through uniform light distribution and optical tracking optimization of the freeform mirror. Compared to a three-eye box system, this invention eliminates the need for individual optical path adjustments for each user's height, significantly simplifying the operation and enhancing the user experience.

[0059] Multi-wavelength optimized design: The reflector in this invention undergoes multi-wavelength optimization to ensure that the color performance and sharpness of the virtual image are unaffected by different wavelengths of light within the 400-700nm visible light range. By applying a multi-layer coating structure to the reflector surface, dispersion and aberrations are effectively reduced, improving the overall quality of the virtual image.

[0060] Advantages of the freeform surface design: The freeform surface design of the secondary reflector allows for more precise control over the direction of light propagation, ensuring that the reflected light evenly covers the entire large-size eye box area. Compared to traditional three-eye box systems, this invention solves the optical distortion problem at multiple heights and viewing angles through its freeform surface design, eliminating the need for complex mechanical adjustments. This ensures that users in different positions within a single eye box can obtain the same virtual image clarity and visual effect.

[0061] 2. Improve the stability and accuracy of the optical system:

[0062] Reduced aberrations and distortions: This invention significantly reduces aberrations and distortions in the optical path through precise calculation and optimization of the optical surfaces of the primary and secondary mirrors. This design ensures that the virtual image remains stable and distortion-free at different field of view angles (e.g., 10° × 3°), especially ensuring that a consistent virtual image can be seen in the upper, middle, and lower parts of the user's eye box.

[0063] Eliminating accuracy loss caused by dynamic adjustment: In existing technologies, the rotation adjustment of the motor-driven reflector is prone to inaccurate positioning after prolonged use, affecting the display position and quality of the virtual image. This invention avoids this problem through a fixed, non-rotating reflector structure design, thereby improving the long-term stability of the optical system.

[0064] 3. Improved user experience:

[0065] Comfort of the large-size monocular eye box: Compared to the traditional three-eye box design, this invention, with its large-size monocular eye box, allows users to obtain a clear and stable virtual image throughout the entire eye box area, eliminating the need for frequent viewing angle adjustments. This not only simplifies the user's operation but also reduces eye fatigue during long drives.

[0066] Noise and vibration reduction: The fixed optical element design of this invention completely eliminates the noise and mechanical vibration generated when the motor drives the mirror to rotate in a traditional HUD system, further improving the user's driving comfort and the overall reliability of the system.

[0067] 4. System cost optimization:

[0068] Optical optimization reduces hardware complexity: Through precise design of the optical system, this invention reduces reliance on complex mechanical structures. This not only lowers production and maintenance costs but also improves system reliability. Compared to traditional three-eye box systems, this invention significantly reduces manufacturing costs, especially by reducing unnecessary mechanical components while maintaining or even improving optical performance.

[0069] Energy saving and environmental protection: This invention eliminates the motor drive structure, which not only reduces the system weight but also reduces power consumption, helping to improve the overall fuel efficiency and power utilization efficiency of the vehicle.

[0070] 5. Expanded scope of application:

[0071] Wide applicability to various vehicles: The optical design of this invention makes it suitable for a wide range of vehicle types, including sedans, SUVs, trucks, and public transportation vehicles. Thanks to the fixed reflector and monocular box design, this system can adapt to the internal structures of different vehicle models while ensuring consistent and reliable optical performance.

[0072] 6. Long system lifespan and high reliability:

[0073] Reduced mechanical wear and failure rate: The motors and transmission mechanisms in traditional HUD systems are prone to wear and tear during prolonged use, thus affecting the system's lifespan. This invention, by eliminating the motor structure and using a fixed reflector design, significantly improves system durability. In a simulated 50,000 km driving environment, tests showed that the system of this invention experienced no mechanical failures, far superior to traditional technologies.

[0074] 7. Virtual image quality and field of view optimization:

[0075] Precise field of view design: Through optimization of the optical system, the field of view of this invention reaches 10° × 3°, providing users with a wider field of view and ensuring that the virtual image is displayed within the user's natural line of sight, reducing the need for head movement. This field of view design is suitable for various driving environments, including city driving and highway driving.

[0076] In summary, this invention, through optical optimization design, solves several problems existing in traditional HUD systems without relying on complex mechanical structures. This not only improves system reliability and user experience but also reduces manufacturing and maintenance costs. The optically optimized monocular AR-HUD optical path system has broad application prospects in multiple technical fields. Attached Figure Description

[0077] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0078] Figure 1 This is a schematic diagram of the optical path of a traditional three-eye AR-HUD.

[0079] Figure 2This is a schematic diagram of the optical path of the AR-HUD single-lens box without rotating curved mirror of the present invention.

[0080] Figure 3 This is a schematic diagram of the angle during the propagation of light in the optical path system of the present invention. Detailed Implementation

[0081] The present invention will be further described in detail below with reference to the specific embodiments and accompanying drawings. Except for the contents specifically mentioned below, the processes, conditions, and experimental methods for implementing the present invention are all common knowledge and general knowledge in the art, and the present invention does not have any particular limitations.

[0082] In existing technologies, in-vehicle head-up display (HUD) systems often use a three-eye box design. The disadvantages of a three-eye box compared to a single-eye box include the following:

[0083] Complex mechanical structure: The three-lens HUD system requires a reflector and a motor drive system to adjust the position of the reflector to accommodate users of different heights. This complex mechanical structure increases the weight and size of the system, which is detrimental to lightweight automotive design.

[0084] High maintenance costs: Because the three-eye box system relies on multiple moving parts, such as motors and mechanical transmission mechanisms, these parts are prone to wear and tear over time, increasing the system's maintenance requirements and long-term costs.

[0085] Reliability and durability issues: Frequent movement and rotation of mechanical components can lead to malfunctions or wear, reducing system reliability. For vehicles operating under various driving conditions, system durability is crucial, and complex mechanical systems increase the potential risk of failure.

[0086] Noise and vibration: The motor and mechanical transmission structure in the three-mirror box system are prone to generating noise and vibration when adjusting the reflectors, which may affect the driving experience. This noise is especially noticeable in high-end models, where it can reduce driver comfort.

[0087] High system cost: The three-eye box system involves motors, complex mechanical structures, and high-precision mirror adjustment mechanisms, which greatly increase the overall cost of the system.

[0088] In Chinese patent application CN112255788A, although the patent application reduces the mechanical complexity of the system, lowers the overall weight and cost, and enhances the system's reliability and durability by fixing the secondary reflector, it mainly relies on adjusting the display area of ​​the image source to adapt to different users' viewing angles. This design has the following disadvantages:

[0089] Loss of image sharpness: Adjusting the display area of ​​the image source may reduce image resolution, especially at the edges of the display area. As the display area of ​​the image source changes, the sharpness and contrast of the image may be inconsistent, especially when the user's viewing angle changes significantly.

[0090] Field of view limitation: This scheme limits the field of view of the virtual image when adjusting the display area. Users may find that the image in the display area does not cover the entire field of view, especially in the edge areas, where the image is not displayed completely or is distorted.

[0091] Limitations of optical performance: Adjusting the display area rather than the position of the reflector alone cannot solve all optical distortion problems. For example, different viewing positions within the eye box may produce varying degrees of aberrations and distortions, resulting in inconsistencies in the sharpness and position of the virtual image.

[0092] Limited applicability: The applicability of this approach may be limited by the size and resolution of the displayed image source. A large, high-resolution display is required to adjust the image area, which increases the cost of the display components and is unsuitable for all types of HUD systems.

[0093] This invention proposes an optically optimized, non-rotating curved mirror-free monocular AR-HUD optical path system. The aim is to simplify the mechanical structure and solve problems in existing HUD systems by optimizing the optical path through changing the system aperture size. The specific technical solution is as follows:

[0094] System components:

[0095] Virtual image: The distance of the virtual image is set to 7.5-10 meters, and the size is 54 inches, providing a clear and easy-to-view display;

[0096] Windshield: Used as a projection medium for displaying virtual images, the imaging light path of the virtual images is reflected into the user's eyes through the windshield (for the light path system of this invention, this is the location of the eye box);

[0097] Eye box: The eye box measures 130*100mm, allowing users to clearly see the virtual image within this range without needing to adjust the position of the reflector.

[0098] A detailed explanation of the factors related to the requirements for setting the size of the eye box is as follows:

[0099] 1. Field of View (FOV):

[0100] The size of the eye-box is directly affected by the field of view (FOV) of the system design. To ensure that users can clearly see the virtual image from different angles, the size of the eye-box needs to take into account the natural field of vision of the human eye. Typically, the field of view in the design is calculated in conjunction with the driver's head movement range to ensure that the user can see the complete virtual image without changing their normal driving posture.

[0101] 2. Focal length and optical path design of the optical system:

[0102] The focal length of the optical elements and the overall optical path design in the system are also important factors in determining the size of the eye box. The length of the optical path and the curvature of the lenses directly affect the angle and range of light entering the eye box. To ensure clear imaging throughout the entire eye box area, precise calculations are required during the design process for the arrangement, curvature, and focal length of the optical elements.

[0103] In the design of an optical path system, the length and angle of the optical path are key factors in ensuring that the system can provide clear virtual images for users of different heights. In a specific implementation, the following are specific data and examples of optical path design:

[0104] Optical path length: The total optical path length from the image source to the windshield is typically designed between 500-800mm, depending on the vehicle's design and interior space. For example, in small cars, a length of 600mm is preferred, while in SUVs or trucks, it may increase to 750mm. The optical path length should be adjusted by the position and angle of the reflectors to ensure that image quality is not limited by the vehicle's interior space.

[0105] Angles of incidence and exit of light:

[0106] First-stage reflector: The first-stage reflector receives light emitted from the image source, and its incident angle is designed to be 20°-30°. The reflection angle is consistent with the light path of the second-stage reflector, usually around 22°, to ensure that the light is accurately transmitted to the second-stage reflector.

[0107] Secondary reflector: The incident angle of the secondary reflector is designed to be 15°-30° to ensure that light can be evenly distributed from the primary reflector to all positions of the windshield to form a complete virtual image.

[0108] Image source exit angle: The exit angle of the image source needs to take into account the stray light generated by sunlight backflow, and is usually 15°-20°, to ensure that the incoming light path will not be reflected back into the secondary optical path.

[0109] Windshield installation angle: The tilt angle of the windshield varies depending on the vehicle model, generally ranging from 20° to 30°. To ensure that reflected light can smoothly enter the user's field of vision, the optical system needs to be optimized in conjunction with the windshield angle to ensure that image clarity is not affected.

[0110] For secondary reflectors, their design and placement directly affect the light path distribution and the sharpness of the virtual image. The following are the design requirements and specific placement instructions:

[0111] Fixed Position: The secondary reflector is fixed at the front of the vehicle, close to the windshield. Its specific position must be precisely aligned with the primary reflector, the windshield, and the user's eye box. A common placement is 300-400mm away from the windshield to ensure that light is evenly reflected onto the windshield and forms a virtual image.

[0112] Mirror tilt angle: The tilt angle of the secondary reflector is designed to be 10°-15°, which allows light to be evenly distributed on the windshield without producing significant aberrations or distortions. This tilt angle is determined through ray tracing simulation to ensure that drivers at different heights can obtain a clear virtual image.

[0113] Regarding the optical optimization of the secondary reflector, this invention employs a freeform surface design to optimize the direction of light propagation, ensuring that the light path uniformly covers the entire eyebox area without a flipping mechanism. Specifically, the optimized mirror shape allows light to travel along the optimal path at all angles, avoiding aberrations and inconsistencies caused by adjusting the display area of ​​the image source in traditional methods.

[0114] Through its freeform surface design, the mirror can have different curvatures at different locations to precisely control the direction of light reflection. This design reduces distortions such as spherical aberration and astigmatism in the optical system, ensuring high-quality imaging of the virtual image at every position within the eyepiece.

[0115] Special design features of the secondary reflector:

[0116] The secondary reflector in this invention employs a free-form surface structure with varying curvature at different locations. This design allows for adjustment of the reflection direction based on the incident angle of light, ensuring uniform light distribution throughout the entire eyepiece. The free curvature of the mirror not only reduces distortion in the optical path but also allows the light, after secondary reflection, to cover a wider field of view (e.g., 10° × 3°), catering to the viewing needs of more users.

[0117] Mirror parameters: For example, the radius of curvature of a secondary mirror varies from 40 to 80 mm, while the curvature of the central area is relatively small, which ensures the uniformity of light under different viewing angles and reduces aberrations and light overlap problems.

[0118] 3. Physiological changes in the position of the human pupil:

[0119] Differences in the position of a user's pupils (such as different heights and seat height adjustments) need to be taken into account. The size of the eye box design needs to accommodate changes in the pupil position of different drivers to ensure that the virtual image falls within the user's pupil range under various conditions.

[0120] 4. Range of head movement:

[0121] The range of head movement a driver makes during normal driving is also an important factor affecting the size of the eye-box. The vertical and horizontal movements of the head need to be covered by the eye-box to ensure that the user can see a clear virtual image without frequently adjusting their head position while driving.

[0122] 5. Optical distortion and aberration control:

[0123] To ensure the sharpness of the virtual image across the entire eyepiece area, the design must also consider the control of optical system distortion and aberrations. An overly large eyepiece may cause significant distortion or aberrations in the optical system at the edges, thus affecting the sharpness of the virtual image. Therefore, the size of the eyepiece must be designed to balance optical performance and user experience.

[0124] 6. Size and resolution of displayed content:

[0125] The size and resolution of the displayed content also affect the settings of the eye box. To ensure that the virtual image seen by the user within the eye box has sufficient resolution and clarity, the design needs to ensure that the displayed content can adapt to the size of the eye box when the virtual image is generated, avoiding blurring or distortion of the content at the edges.

[0126] 7. Security and User Experience:

[0127] When designing the size of the driver's eye box, driving safety and user experience must also be considered. A properly sized eye box ensures that the driver can clearly see necessary driving information in various situations, thereby improving driving safety and the user's driving experience.

[0128] In conclusion, the setting of the eye box size is the result of comprehensive consideration of multiple factors. It requires balancing and optimization in multiple aspects such as optical design, user physiological characteristics, and driving habits to ensure that the final HUD system can provide the best visual effect and user experience in various driving conditions.

[0129] The size of the eye box in this invention is a size that is more suitable for this invention, calculated after fully taking into account the above factors.

[0130] The primary and secondary reflectors in this invention are used to reflect the image generated by the image source onto the windshield. The secondary reflector is fixed and does not require rotation or adjustment via a motor drive mechanism.

[0131] Optical path design in this invention:

[0132] The image generated by the image source is first reflected by a first-stage mirror.

[0133] The light is then reflected by a secondary mirror and finally projected onto the windshield to form a virtual image.

[0134] Light is reflected off the windshield and enters the user's field of vision, allowing the user to clearly see the virtual image within that field of vision.

[0135] Optical parameters:

[0136] Field of view: The system has a field of view of 10°*3°, which can provide a sufficiently wide field of view to adapt to different driving environments.

[0137] Downward viewing angle: The downward viewing angle is 2° to ensure that the virtual image is displayed within the user's natural line of sight, reducing head movement.

[0138] Design without rotating curved mirrors:

[0139] The secondary reflector in this invention is a fixed curved mirror, eliminating the need for rotation via a motor drive mechanism. This design significantly simplifies the mechanical structure, reduces system weight and complexity, and avoids potential noise issues.

[0140] Through optical tracking calculations and optimizations, it is ensured that users can see a complete virtual image within a 130*100mm eye box, regardless of height.

[0141] The optical tracing calculation and optimization refer to the optimization of light propagation paths and optical imaging quality. Optical tracing calculation is mainly used to analyze the propagation path of light, while optical imaging quality optimization is mainly to improve the imaging effect by adjusting and optimizing the hardware.

[0142] 1. Optical Ray Tracing (Optimization of Ray Propagation Path)

[0143] Optical tracing calculation is a key technology in the design of optical systems. It analyzes and optimizes the arrangement and shape of optical elements by simulating the path of light propagation within the system. Specifically, in the HUD system of this invention, the optical tracing calculation process includes the following key steps:

[0144] Ray emission and tracking:

[0145] Starting from the image source, multiple light rays are emitted, simulating their paths after passing through the primary mirror, secondary mirror, and windshield. For each light ray, the position and angle of each optical surface it passes through are recorded, with particular attention paid to the reflection path on the secondary mirror.

[0146] The path calculations for these rays will take into account parameters such as the size of the display image source, the position of the aperture, and the focal length and curvature of the optical system.

[0147] Multi-point ray tracing:

[0148] To ensure optical performance across the entire 130*100mm eye box area, ray tracing is performed at multiple sampling points within the eye box. For example, rays are emitted from three different positions—the top, middle, and bottom—to simulate the light paths when users of different heights view the virtual image.

[0149] By analyzing the behavior of light rays at different locations on the reflector and windshield, it can be determined whether the light rays can ultimately fall into the user's pupil and form a clear virtual image.

[0150] 2. Optical system optimization (optical imaging quality optimization)

[0151] After optical tracing calculations are completed, the system is optimized to ensure best optical performance across the entire eyebox. The optimization process mainly includes the following aspects:

[0152] Optimization of the reflector surface:

[0153] By optimizing the surface design of the reflectors (especially secondary reflectors), it is ensured that light is precisely guided to various positions within the eyepiece as it passes through the reflectors. Specific optimization methods include adjusting the radius of curvature and surface shape (aspherical or freeform) of the reflectors to reduce aberrations and distortion.

[0154] Aberration and distortion control:

[0155] During optical tracing, the aberrations and distortions of each ray are recorded. By adjusting the position and angle of the reflector and windshield, the overall optical performance of the system is optimized to ensure that light rays at every position in the eye box are focused within the user's pupil range, thereby forming a clear virtual image.

[0156] Optical performance evaluation:

[0157] For different sampling points, the quality of light focusing, the sharpness of the virtual image, and the brightness are evaluated. During the optimization process, system parameters, including the mirror tilt angle, eccentricity, surface coefficient, and constraints, are continuously adjusted until the expected optical performance is achieved throughout the entire eyebox.

[0158] 3. Ensure user experience

[0159] Through the aforementioned optical tracking calculation and optimization process, the HUD system of this invention can provide users with a clear and stable virtual image display within a 130*100mm eye box. This means that regardless of the user's height, they can obtain the best visual experience within the predetermined eye box without adjusting the position of the reflector.

[0160] In addition to the design optimization of the secondary reflector, this invention has also made several optimizations in other optical design aspects to further enhance the user experience. The following is a detailed description of these optimizations:

[0161] 1. Optimized design of the primary reflector

[0162] Aspherical design:

[0163] The primary reflector employs an aspherical or freeform surface design. This design effectively reduces spherical aberration, allowing light rays to be more precisely focused onto the secondary reflector after passing through the primary reflector, ultimately forming a clear virtual image.

[0164] The aspherical design also helps control the divergence and convergence of the beam, thereby improving the overall optical efficiency of the system and ensuring uniform brightness and clarity throughout the entire eye box.

[0165] Anti-reflective coating:

[0166] The primary reflector surface is coated with multiple layers of anti-reflective material to reduce energy loss during reflection and improve light transmittance. This not only increases the brightness of the virtual image but also effectively reduces glare and ghosting, enhancing the user's visual experience.

[0167] 2. Optimization of image source display

[0168] High-resolution display technology:

[0169] This invention employs high-resolution display technology (such as LCOS or DLP optical engines) to ensure the clarity and detail of the virtual image across the entire eye-viewing area. This display technology can provide higher pixel density and a wider color gamut, making the virtual image closer to the real object and enhancing the immersive driving experience.

[0170] 3. Optimized settings for the aperture.

[0171] Adjustable aperture design:

[0172] The size and position of the aperture are precisely calculated and adjusted to optimize the angle and range of light entering the reflector, ensuring that light is effectively focused at all points within the eye box. This design also helps reduce light loss in edge areas, improving optical performance throughout the entire eye box.

[0173] 4. System thermal management and heat dissipation design

[0174] Passive heat dissipation structure:

[0175] The system incorporates an optimized passive cooling design (the display image source mounting base uses a high thermal conductivity material such as aluminum alloy) to ensure that the display image source and optical components can still operate stably in high-temperature environments. This design reduces the problems of optical performance degradation and shortened component lifespan caused by overheating, ensuring long-term stable operation of the system.

[0176] Scope of application:

[0177] The system is suitable for all types of vehicles, including cars, SUVs, trucks, and public transportation vehicles.

[0178] It is also applicable to other fields that require displaying augmented reality information, such as aviation and shipping.

[0179] Through the above technical solutions, the present invention provides an efficient, reliable and economical single-eye AR-HUD optical path system, which effectively solves the shortcomings of the prior art and has significant application prospects.

[0180] The optical design requirements and factors in this invention also include the following:

[0181] The monocular optical design of this invention aims to ensure that the user can clearly see the virtual image within a 130*100mm eyebox area without adjusting the position of the reflector. To achieve this goal, the following key factors and requirements were considered in the optical design:

[0182] 1. Field of View (FOV) Optimization:

[0183] The system is designed with a field of view of 10°*3°, which is set based on the typical visual requirements of a driver. Through precise calculations, it is ensured that light can be evenly distributed throughout the entire eye box area within this field of view, thereby guaranteeing that the user can see a complete virtual image throughout the entire eye box area.

[0184] 2. Precise control of optical path design:

[0185] The length of the optical path, the reflection angle, and the convergence and divergence of the beam are all precisely calculated and optimized. This ensures that the light emitted from the display image source, after passing through the primary and secondary reflectors, forms a clear virtual image on the windshield and ultimately enters the user's eyes, regardless of changes in the user's viewing angle.

[0186] 3. Aspherical design of the reflector:

[0187] The secondary reflector employs an aspherical or freeform surface design, which effectively reduces aberrations and distortion, ensuring consistent focus and sharpness of light throughout the entire eye box. The reflector's surface shape has undergone multiple simulations and optimizations to guarantee that light can be accurately focused into the user's pupil under different viewing angles and head positions.

[0188] 4. Aperture optimization:

[0189] The position and size of the aperture directly affect the angle and amount of light entering the reflector. By optimizing the aperture design, it is ensured that the light can evenly cover the entire eyepiece area when the light path passes through the reflector, avoiding uneven imaging problems caused by excessively concentrated or dispersed light.

[0190] 5. Multi-point sampling and simulation verification:

[0191] During the optical design process, multi-point sampling and ray tracing technologies were used to simulate and verify the top, middle, and bottom positions of the eye box. By simulating the light paths at multiple sampling points, it was ensured that the brightness, sharpness, and color of the virtual image remained consistent throughout the entire eye box, achieving the best user experience.

[0192] 6. Material selection and surface treatment:

[0193] The choice of materials and surface treatment for the reflector and windshield also have a direct impact on optical performance. High transmittance and low dispersion optical materials can reduce energy loss and chromatic aberration during light propagation, while anti-reflective coatings on the surface can reduce stray light and glare interference, further improving the clarity and contrast of the virtual image.

[0194] In addition to its advantages in optical systems, this invention, like existing mirror-fixed HUD systems, includes the following innovations and advantages:

[0195] Reduced system weight: By eliminating the motor drive mechanism, the overall weight of the system is significantly reduced, which is beneficial for lightweight vehicle design.

[0196] Reduced costs: The simplified mechanical structure not only reduces manufacturing costs but also maintenance costs, improving the system's economic efficiency.

[0197] Improved reliability and stability: The fixed reflector design reduces the number of moving mechanical parts, significantly improving the stability and durability of the system, especially during vehicle operation.

[0198] Enhanced user experience: By optimizing the optical design, we not only ensure that users can clearly see the virtual image within the eye box, guaranteeing driving experience and safety, but also reduce problems such as noise and gear misalignment that may occur with traditional motor structures.

[0199] Specifically,

[0200] Simplification of mechanical structure:

[0201] Existing HUD systems typically employ a three-lens design and rely on motor-driven mechanisms to rotate and adjust the position of the reflectors to accommodate users of different heights. This complex mechanical structure not only increases the system's weight and cost but can also lead to mechanical failures and noise problems.

[0202] This invention employs a single-eye box design and addresses the adaptation issues for users of different heights through a fixed, non-rotating curved mirror and a large-size single-eye box optical design, thereby completely eliminating the need for a motor drive mechanism. This significantly simplifies the system's mechanical structure, reduces its weight, lowers manufacturing and maintenance costs, and solves the noise problem.

[0203] System weight reduction:

[0204] By eliminating the motor drive mechanism, the weight of the HUD system of this invention is significantly reduced. For example, a typical three-eye HUD system weighs approximately 4 kg, while the single-eye HUD system of this invention weighs approximately 3.5 kg, a weight reduction of over 10%. This not only contributes to lightweight vehicle design but also improves vehicle fuel efficiency and dynamic performance.

[0205] Cost reduction:

[0206] Traditional HUD systems suffer from complex mechanical structures, resulting in high manufacturing and maintenance costs. The manufacturing cost of a traditional three-eye HUD system ranges from approximately 700 to 2000 yuan per unit. In contrast, the single-eye HUD system of this invention, due to its simplified mechanical structure, reduces the manufacturing cost to 620 to 1850 yuan per unit, a cost reduction of approximately 10%. This makes the HUD system of this invention more competitive in the market.

[0207] Improve system reliability and stability:

[0208] In traditional HUD systems, the motor drive mechanism is prone to wear and failure during long-term use, affecting the system's reliability and stability.

[0209] This invention eliminates the motor drive mechanism and reduces the number of moving mechanical parts through a fixed, non-rotating curved mirror design, thereby significantly improving the system's reliability and stability. Experiments have shown that under simulated 50,000 km driving conditions, the HUD system of this invention experienced no mechanical failures, while the failure rate of traditional systems was 5%.

[0210] Improved user experience:

[0211] This invention utilizes a single-eye box optical design to ensure that users can clearly see the virtual image within a 130*100mm eyebox area without adjusting the position of the reflector. This not only improves display stability but also eliminates noise and gear misalignment issues that may occur during adjustment in traditional systems, further enhancing the user's driving experience and safety.

[0212] Wide range of applications:

[0213] The HUD system of this invention is designed for various types of vehicles, including cars, SUVs, trucks, and public transportation vehicles. It can also be applied to other fields requiring the display of augmented reality information, such as aviation and maritime transport. Compared to traditional HUD systems, the stability of this invention makes it more widely applicable and has greater market potential.

[0214] In summary, this invention demonstrates significant improvements and advantages over existing technologies in terms of mechanical structure, weight, cost, reliability, user experience, and applicability. These beneficial effects make the monocular AR-HUD optical path system of this invention more competitive and practical in real-world applications.

[0215] The HUD system of this invention is designed for various types of vehicles, including cars, SUVs, trucks, and public transportation vehicles. It can also be applied to other fields requiring the display of augmented reality information, such as aviation and maritime transport. Compared to traditional HUD systems, the stability of this invention makes it more widely applicable and has greater market potential.

[0216] In summary, this invention demonstrates significant improvements and advantages over existing technologies in terms of mechanical structure, weight, cost, reliability, user experience, and applicability. These beneficial effects make the monocular AR-HUD optical path system of this invention more competitive and practical in real-world applications.

[0217] Comparative Example: Traditional Three-Eye Box AR-HUD System

[0218] See Figure 1 This embodiment describes a traditional three-eye AR-HUD system, and its optical path diagram is shown below. Figure 1 As shown:

[0219] 1. Virtual Image: The virtual image distance is set to 7.5 meters and the size is 54 inches to ensure that the driver can clearly see the virtual image.

[0220] 2. Windshield: Used as a projection medium to display virtual images. The imaging light path of the virtual image is reflected through the windshield and enters the user's eyes.

[0221] 3. Eye box: Includes upper eye box, middle eye box and lower eye box, which are adapted to users of different heights and are achieved by adjusting the position of the secondary reflector.

[0222] 4. Primary and secondary reflectors: The image generated by the image source is first reflected by the primary reflector, and then reflected by the rotatable secondary reflector to the windshield to form a virtual image.

[0223] The secondary reflector is rotated by a motor to adjust the reflection angle to fit the eye box position of different users. However, this design is complex, heavy, expensive, and has noise issues.

[0224] Example 1: Single-lens AR-HUD system without rotating curved mirror

[0225] See Figure 2 This embodiment describes a monocular AR-HUD system without rotating curved mirrors, and its optical path diagram is shown below. Figure 2 As shown:

[0226] 1. Virtual Image: The virtual image distance is set to 7.5 meters and the size is 54 inches, providing a clear and easy-to-view display.

[0227] 2. Windshield: Used as a projection medium to display virtual images. The imaging light path of the virtual image is reflected through the windshield and enters the user's eyes.

[0228] 3. Eye Box: The eye box measures 130*100mm, allowing users to clearly see the virtual image within this range without needing to adjust the position of the reflector.

[0229] 4. Primary and secondary reflectors: The image generated by the light source is first reflected by the primary reflector, and then the light is reflected by the fixed secondary reflector onto the windshield to form a virtual image.

[0230] 5. Optical Design: Through optical tracking calculations and optimizations, it is ensured that users can see a complete virtual image within a 130*100mm eye box, regardless of height.

[0231] Optical parameters:

[0232] Field of view: The system has a field of view of 10°*3°, which can provide a sufficiently wide field of view to adapt to different driving environments.

[0233] Downward viewing angle: The downward viewing angle is 2° to ensure that the virtual image is displayed within the user's natural line of sight, reducing head movement.

[0234] Design without rotating curved mirrors:

[0235] The secondary reflector is a fixed curved mirror, eliminating the need for a motor-driven rotation mechanism. This design significantly simplifies the mechanical structure, reduces system weight and complexity, and avoids potential noise issues.

[0236] Innovation points and advantages:

[0237] Reduced system weight: By eliminating the motor drive mechanism, the overall weight of the system is significantly reduced, which is beneficial for lightweight vehicle design.

[0238] Reduced costs: The simplified mechanical structure not only reduces manufacturing costs but also maintenance costs, improving the system's economic efficiency.

[0239] Improved reliability and stability: The fixed reflector design reduces the number of moving mechanical parts, significantly improving the stability and durability of the system, especially during vehicle operation.

[0240] Enhanced user experience: By optimizing the optical design, we not only ensure that users can clearly see the virtual image within the eye box, guaranteeing driving experience and safety, but also reduce problems such as noise and gear misalignment that may occur with traditional motor structures.

[0241] Example 2: AR-HUD system without rotating curved mirror applied to other vehicle types

[0242] In addition to passenger cars, the non-rotating curved mirror monocular AR-HUD system of this invention can also be applied to other vehicle types, such as SUVs, trucks, and public transportation vehicles.

[0243] 1. The system structure is the same as in Example 1, but the position and size of the eye box are adjusted appropriately for different vehicle types to ensure that all users can clearly view the virtual image.

[0244] 2. Optical Design: By adjusting the freeform mirror shape, downward viewing angle, and optical path parameters, we ensure that the virtual image can be clearly imaged on the windshields of different vehicle types.

[0245] Beneficial effects:

[0246] Reduce the overall weight of different types of vehicles: especially in public transportation, reducing weight helps reduce energy consumption.

[0247] Reduced vehicle manufacturing and maintenance costs: Standardized designs applicable to various vehicle types simplify the production process and reduce costs.

[0248] Improved system reliability and durability: The fixed reflector design reduces moving mechanical parts and adapts to various driving environments.

[0249] Through the above embodiments, the present invention provides an efficient, reliable and economical single-lens AR-HUD optical path system without rotating curved mirrors, which effectively solves the shortcomings of the prior art and has significant application prospects.

[0250] The scope of protection of this invention is not limited to the above embodiments. Any variations and advantages that can be conceived by those skilled in the art without departing from the spirit and scope of this invention are included in this invention and are protected by the appended claims.

Claims

1. An optically optimized, non-rotating curved mirror monocular AR-HUD optical path system, characterized in that, The optical path system includes: an image source, a primary reflector, a secondary reflector, and a windshield; the light generated by the image source passes through the primary reflector, the secondary reflector, and the windshield to generate a virtual image in front of the windshield, which is then observed by the human eye at the observation position indicated by the eye box. The secondary reflector is fixedly mounted on the support bracket of the AR-HUD optical path system. The free-form surface is designed based on multiple ray tracing simulations, and the surface coating is optimized using a multi-wavelength optimization method.

2. The optical path system as described in claim 1, characterized in that, The image source generates light rays to display the image. The light rays pass through a primary reflector and a secondary reflector in sequence, and are then projected onto the windshield to form a virtual image. The primary reflector receives light emitted from the image source and reflects it to the secondary reflector; The secondary reflector reflects the light transmitted from the primary reflector and projects it onto the windshield to form a virtual image; The windshield serves as a projection medium for virtual images, projecting the generated virtual image into the user's line of sight through the reflection of light.

3. The optical path system as described in claim 1, characterized in that, The virtual image is 7.5-10m away from the position where the virtual image is observed by the human eye, and its size is 54 inches; the eye box is a monocular eye box, and its dimensions are 130×100mm; and / or, An aperture is provided at the position of the eye box, and the aperture has a size of 130×50mm.

4. The optical path system as described in claim 1, characterized in that, The image source includes an LCOS optical engine and a DLP optical engine; the mounting base of the image source uses a material with high thermal conductivity, and the thermal conductivity is not less than 200 W / (m·K); The primary reflector adopts an aspherical or free-form mirror shape and is coated with one or more anti-reflective coatings. The secondary reflector adopts an aspherical or freeform mirror shape.

5. The optical path system as described in claim 4, characterized in that, The image source emission angle is 15°-20°; and / or, The curvature of the primary reflector is 0.0011563, the incident angle of light is 20°-30°, and the reflection angle is 22°; and / or, The secondary reflector has a tilt angle of 10°-15°, a radius of curvature of 40-80mm, and an incident angle of light of 15°-30°; and / or, The windshield is tilted at an angle of 20°-30°.

6. A method for optimizing the light path of a large-size monocular camera, characterized in that, The optimization method includes light propagation path optimization and optical imaging quality optimization; The light propagation path optimization includes optimizing the light propagation path through optical tracing calculations and simulations; The optical imaging quality optimization includes mirror surface optimization, aberration and distortion control, and optical performance evaluation.

7. The optimization method as described in claim 6, characterized in that, The optimization of the light propagation path includes the following steps: Step 1: Emit and track multiple light rays, and record the position and angle of the light rays on different optical surfaces; Step 2: Perform ray tracing at multiple sampling points on the eye box to simulate the light path from different user perspectives and determine whether the light can eventually enter the user's pupil to form a clear virtual image.

8. The optimization method as described in claim 6, characterized in that, In optical imaging quality optimization, the mirror surface optimization involves optimizing the design of the mirror surface, adjusting the radius of curvature and surface shape, and reducing optical aberrations and distortions. The aberration and distortion control records the aberrations and distortions of light after passing through the optical elements. By adjusting the position and angle of the reflector and the windshield, the overall optical performance is optimized to ensure that light can be focused into the user's pupil at every position in the eye box. The optical performance evaluation assesses the optical performance at different sampling points within the eye box and continuously adjusts the system parameters based on the evaluation results to ensure optimal optical performance across the entire eye box area.

9. The optical path system as described in any one of claims 1-5, or the optimization method as described in any one of claims 6-8, is applied in the design of vehicle HUD structure and optical path.

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