HUD Optical Aberration Correction Method and Related Equipment

Abstract

The present invention relates to the technical field of head-up display, and specifically to a HUD optical aberration correction method, system, device and vehicle. The steps of the correction method include: generating a light beam through an LED light source or a laser light source, and adjusting the brightness and color parameters of the LED light source or the laser light source through a control circuit to adapt to different display requirements and environmental conditions; the light beam is preliminarily shaped and collimated through a beam shaping element until a suitable divergence angle and spot size are met to adapt to the requirements of a coupling element. The present invention effectively solves the problems of large volume, limited field of view angle, small eye box range and insufficient imaging clarity in the prior art by performing one-dimensional or two-dimensional pupil expansion on the light beam emitted by the optical engine through an optical waveguide, and then performing field of view expansion and aberration correction through a free-form mirror.

Description

Technical Field

[0001] The present invention relates to the technical field of head-up display, and particularly to an HUD optical aberration correction method, system, device and vehicle. Background Art

[0002] Head-Up Display (HUD) projects vehicle-related information directly into the driver's field of view, reducing the frequency of looking down at the instrument panel or the central control screen during driving, thereby improving driving comfort and safety. Existing HUD technologies have many limitations. For example, C-HUD uses an external transparent glass for multiple folding reflections. Although it can form a virtual image at a relatively far distance, the device is large in size and difficult to miniaturize. Although W-HUD uses the windshield as the working surface of the optical system and can provide a farther virtual image distance, it still needs to be improved in terms of the Field of View (FOV), Eyebox range, imaging distance, and display clarity. Although AR-HUD can provide a long-distance virtual image and combine it with the real scene, it performs poorly in terms of image quality optimization and the adjustable range of the Eyebox. In addition, most traditional HUD optical systems use complex discrete optical elements, resulting in a large volume, heavy weight, and difficulty in large-scale market promotion and application. Although the HUD systems in the prior art have solved the volume problem to a certain extent, they still have obvious deficiencies in optical aberration correction, color uniformity, and the adjustable range of the Eyebox, and need to be further optimized to meet the requirements of modern applications for miniaturization, high image quality, and high performance. Summary of the Invention

[0003] The present invention provides an HUD optical aberration correction method, system and device to solve the technical problems of the large volume and limited field of view of the HUD optical system.

[0004] The technical solutions of the present invention to solve the above technical problems are as follows:

[0005] On the one hand, an HUD optical aberration correction method is provided, and the steps of the correction method include:

[0006] Generating a light beam through an LED light source or a laser light source, and adjusting the brightness and color parameters of the LED light source or the laser light source through a control circuit to adapt to different display requirements and environmental conditions;

[0007] The light beam is initially shaped and collimated by a beam shaping element until it meets appropriate divergence angles and spot sizes to meet the requirements of the coupling element;

[0008] The light beam enters the optical waveguide through an input region with a grating structure, and the grating structure deflects the light beam so that it undergoes total internal reflection transmission within the optical waveguide until it reaches the output region;

[0009] The coupled light beam coupled out from the optical waveguide passes through a freeform mirror to form a corrected light beam for field of view expansion and aberration correction. The freeform mirror flips according to the eye box adjustment range to ensure clear imaging at the eye positions of different drivers;

[0010] The corrected light beam is reflected by the windshield into the driver's field of view to form a navigation virtual image for presenting navigation information on the road ahead to the driver;

[0011] The control circuit detects the environmental information, the user's input commands, and the internal state of the system in real time, and dynamically adjusts the aberration correction parameters, the light source parameters, and the image display parameters to optimize the display effect.

[0012] Furthermore, the design of the grating structure in the input region of the optical waveguide satisfies the following relational expressions:

[0013] ;

[0014] where θ0 is the deflection angle of the grating incident light, θ1 is the deflection angle of the grating outgoing light, is the tilt angle of the grating incident light, is the tilt angle of the grating outgoing light, m is the diffraction order, λ is the wavelength of light, d is the grating constant, and n is the refractive index of the incident medium.

[0015] Furthermore, the grating structure is a surface relief grating or a volume holographic grating, and the grating structure includes a one-dimensional grating, a two-dimensional grating, or a super grating.

[0016] Furthermore, the light beam after passing through the diffractive optical waveguide satisfies that the propagation angle of the light in the waveguide is greater than the Brewster angle:

[0017] ;

[0018] where α is the propagation angle of the light in the waveguide, n b is the refractive index of the optical waveguide substrate, 1.4 ≤ n b ≤ 2.8;

[0019] The optical waveguide substrate material is glass, resin, or organic polymer crystal, and the thickness of the optical waveguide substrate is d b , 0.5 mm ≤ d b ≤ 5 mm.

[0020] Furthermore, the flipping angle of the freeform mirror is calculated by the following calculation formula:

[0021] ;

[0022] Among them, θ flip is the flipping angle of the free-form mirror, h eye is the height of the driver's eyes, h pivot is the height of the rotation axis of the free-form mirror, d mirror is the distance between the free-form mirror and the windshield.

[0023] Furthermore, the flipping angle of the free-form mirror is adjusted in real time according to the driver's body posture and eye position to ensure that drivers of different heights and body shapes can clearly see the HUD information.

[0024] Furthermore, during the formation of the navigation virtual image, the brightness and color balance of the light beam are adjusted in real time through the control circuit to adapt to different ambient light conditions and ensure the visual effect of the image.

[0025] On the other hand, a HUD optical aberration correction system is provided for implementing the above-mentioned HUD optical aberration correction method. The correction system includes:

[0026] An optical engine, which includes a high-brightness LED or laser light source, is used to generate a light beam and adjust the brightness and color parameters of the light beam to provide a clear, bright, and colorful image;

[0027] An optical waveguide, including an input coupling region and an output coupling region. The input coupling region has a grating structure that can deflect the light beam for total internal reflection transmission within the optical waveguide;

[0028] An aberration correction element, including a free-form mirror, is used to perform field of view expansion and aberration correction on the light beam coupled out from the optical waveguide. The free-form mirror flips the lens angle around the rotation axis according to the eye box adjustment range to achieve clear imaging within a large eye box range;

[0029] A windshield, which is used to reflect the corrected light beam to form a navigation virtual image;

[0030] A control circuit, which is connected to and controls the optical waveguide element, aberration correction element, light source system, and image generation unit, is used to control and operate the correction system;

[0031] The aberration correction element further includes:

[0032] A binocular disparity correction module, which is used to optimize binocular disparity;

[0033] A distortion correction module, which is used to correct the distortion in the optical system;

[0034] MTF optimization module, which is used to optimize the modulation transfer function of the correction system and improve the resolution and clarity of the image.

[0035] In another aspect, a HUD optical aberration correction device is provided. The correction device includes the HUD optical aberration correction system as described above. The correction device further includes a naked-eye 3D implementation system, which is used for naked-eye 3D display by integrating a multi-layer optical waveguide structure and optical components in the optical waveguide element.

[0036] In yet another aspect, a vehicle is provided. The vehicle includes the HUD optical aberration correction device as described above. The vehicle further includes:

[0037] A front windshield, which serves as the display surface of the correction device and is used to reflect the light beam to form a navigation virtual image;

[0038] A control circuit, which is used to detect the environmental information, the user's input command and the internal state of the system in real time, and dynamically adjust the aberration correction parameters, light source parameters and image display parameters to optimize the display effect.

[0039] The beneficial effects of the present invention are as follows:

[0040] In the present invention, the light beam emitted by the optical engine is subjected to one-dimensional or two-dimensional pupil expansion through the optical waveguide, and then the field of view is expanded and the aberration is corrected through the free-form mirror, effectively solving the problems of large volume, limited field of view angle, small eye box range and insufficient imaging clarity in the prior art.

[0041] Specifically, the present invention utilizes a multi-layer optical waveguide structure and a mature free-form mirror processing technology to achieve the miniaturization and compact design of the system. The volume is reduced by more than 50%, and the weight is reduced by more than 50%, improving the flexibility of the device. The free-form mirror can not only effectively expand and collimate the light beam, but also flip according to the adjustment range of the eye box to ensure that drivers in different driving positions can clearly see the HUD information. By controlling the circuit to adjust the environmental information, user input and system state in real time, the present invention can dynamically optimize the aberration correction parameters, light source parameters and image display parameters, further improving the clarity, contrast and color accuracy of the image.

[0042] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it according to the content of the specification, the following describes the preferred embodiments of the present invention in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a flowchart of the HUD optical aberration correction method in an embodiment of the present invention;

[0044] Figure 2 It is a schematic diagram of the principle of the present invention;

[0045] In the attached drawings, the list of components represented by each reference numeral is as follows:

[0046] 1. Optical engine; 2. Optical waveguide; 3. Free-form mirror; 4. Automobile windshield; 5. Human head model. Specific embodiments

[0047] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] The term "including" and any variation thereof in the specification and claims of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices. In addition, the use of "and / or" in the specification and claims means at least one of the connected objects. For example, A and / or B means including three cases: A alone, B alone, and both A and B exist.

[0049] In the embodiments of the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present invention should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present relevant concepts in a specific manner.

[0050] The present invention provides the following preferred embodiments:

[0051] Embodiment 1

[0052] To solve the problems of large volume, limited field of view angle, small eye box range, and insufficient display clarity existing in the existing HUD system, this embodiment proposes a method for correcting optical aberration of a HUD based on an optical waveguide. Specifically, in this embodiment, by optimizing the design of the light source, beam shaping, grating structure, and free-form mirror, the efficient operation and high-image-quality display of the optical waveguide HUD system are realized.

[0053] As Figure 1 shown, the steps of the correction method include:

[0054] S100. Generate a light beam through an LED light source or a laser light source, and adjust the brightness and color parameters of the LED light source or the laser light source through a control circuit to adapt to different display requirements and environmental conditions.

[0055] S200. The light beam undergoes preliminary shaping and collimation through a beam shaping element until it meets the appropriate divergence angle and spot size to meet the requirements of the coupling element.

[0056] S300. The light beam enters the optical waveguide through the coupling region with a grating structure. The grating structure deflects the light beam so that it undergoes total internal reflection transmission within the optical waveguide until it reaches the coupling-out region.

[0057] S400. The coupled light beam coupled out from the optical waveguide passes through a freeform mirror to form a corrected light beam for the expansion of the field of view and the correction of aberration. The freeform mirror flips according to the eye box adjustment range to ensure clear imaging of the eye positions of different drivers.

[0058] S500. The corrected light beam is reflected by the windshield into the driver's field of view to form a navigation virtual image to present the navigation information on the road ahead to the driver.

[0059] S600. The control circuit detects the environmental information, the user's input commands, and the internal state of the system in real time, and dynamically adjusts the aberration correction parameters, the light source parameters, and the image display parameters to optimize the display effect.

[0060] In this embodiment, the optical engine uses a high-brightness LED light source or a laser light source. These light sources have high luminous efficiency and color rendering properties, and can provide clear and bright images under different environmental conditions. By dynamically adjusting the brightness and color parameters of the light source through the control circuit, different display requirements can be adapted. For example, in the daytime or strong light environment, the control circuit can adjust the brightness of the light source to avoid dazzling the driver while maintaining clarity; in the nighttime or low light environment, the control circuit can appropriately reduce the brightness to reduce light pollution and energy consumption.

[0061] Furthermore, the light beam generated by the LED light source or the laser light source undergoes preliminary shaping and collimation through a beam shaping element. The beam shaping element can be a lens group or a mirror group, and its purpose is to make the light beam have an appropriate divergence angle and spot size to meet the requirements of the coupling element. It should be understood that the design of the beam shaping element takes into account the characteristics of the optical engine light source and the entrance size of the optical waveguide to ensure high-efficiency coupling of the light beam when entering the optical waveguide.

[0062] Even further, the light beam enters the optical waveguide through the coupling region with a grating structure. The grating structure can be a surface relief grating or a volume holographic grating, and its function is to deflect the light beam so that it undergoes total internal reflection transmission within the optical waveguide.

[0063] Furthermore, in traditional field of view expansion, Fresnel lenses are mostly used. In this embodiment, however, the light beam coupled out from the optical waveguide is expanded in the field of view and corrected for aberration through a freeform mirror. Using a Fresnel lens will cause Fresnel fringes in imaging, affecting the imaging effect and causing visual discomfort; a freeform surface is a smooth surface, and the imaging effect is better. Specifically, when imaging with a Fresnel lens, Fresnel fringes are likely to occur. First, due to the special concentric ring structure of the lens, light rays are refracted and diffracted differently, resulting in optical path differences, and optical wave interference forms bright and dark fringes. Second, the processing accuracy of the lens is limited, and the size, shape error, and surface roughness of the ring will change the propagation of light rays, triggering additional interference. Third, the good coherence of the light source or the refractive differences of light with different wavelengths will enhance the interference effect. Fourth, temperature changes and mechanical stresses in the environment cause the lens to deform, changing the light path and optical path difference, which also promotes the generation of Fresnel fringes. The Fresnel fringes generated during imaging with a Fresnel lens will cause the image seen by the observer to have bright and dark stripes, reducing the image clarity and contrast, interfering with the observation of the imaging subject, making it difficult to distinguish details, affecting the visual effect, making the information transmission inaccurate, and causing visual discomfort and cognitive deviation. A freeform mirror is a smooth surface. Because it has no special structures such as the concentric rings of a Fresnel lens, light rays are reflected or refracted more regularly on its continuous smooth surface. Moreover, it mainly changes the propagation of light rays based on the continuous surface, following the conventional optical laws. Coupled with the avoidance of irregular light interference during design and manufacturing, it will not generate Fresnel fringes, and the imaging effect is better. The freeform mirror does not generate Fresnel fringes, and can bring a clear and pure imaging experience to the observer. The image is free from interference of miscellaneous patterns, with every detail clearly shown and accurate color reproduction. Whether viewing a scene or an image, it is more vivid and natural, the visual experience is comfortable, and it can greatly improve the concentration and immersion of observation.

[0064] Furthermore, the design of the freeform mirror allows it to be flipped according to the eye box adjustment range, so as to adapt to the eye positions of different drivers. It can be understood that the flipping angle of the freeform mirror can be adjusted according to specific application requirements and the user's sitting posture to ensure that each driver can see clear HUD information within a comfortable field of view. This design not only improves the user experience, but also reduces visual fatigue caused by frequently adjusting the head or body posture.

[0065] Furthermore, the corrected light beam is reflected by the windshield into the driver's field of view, forming a navigation virtual image. As the final reflecting surface, the windshield can accurately reflect the light beam to the position of the driver's eyes, ensuring the clear display of navigation information. It should be understood that the reflection angle and reflection efficiency of the windshield are carefully optimized to reduce light loss and improve image quality.

[0066] Further, the control circuit continuously detects the environmental information, the user's input commands, and the internal state of the system, and dynamically adjusts the aberration correction parameters, light source parameters, and image display parameters based on this information to optimize the display effect. For example, the control circuit can continuously monitor the environmental light intensity and adjust the brightness of the light source accordingly; monitor the user's sitting posture and head position, and adjust the flipping angle of the free-form mirror; monitor the internal temperature of the system and adjust the operating state of the light source to ensure the best display effect under various conditions.

[0067] The benefits of this embodiment are that by optimizing the designs of the optical engine light source, beam shaping, grating structure, and free-form mirror, the efficient operation and high-image-quality display of the waveguide HUD system are achieved. Through the flipping design of the free-form mirror, the viewing range of the eyebox is increased, ensuring that different drivers can see clear HUD information within a comfortable field of view. In addition, the real-time parameter adjustment and optimization mechanism further enhance the adaptability of the system, providing a more comfortable and safe driving environment for the driver.

[0068] Principle of the embodiment: As Figure 2 shown, the optical engine 1, as an image generator, can transmit the image carrying navigation information to the optical waveguide 2 through total reflection. The coupling region of the optical waveguide 2 has a grating structure that can deflect the light, enabling the light to be totally reflected and transmitted within the optical waveguide 2, and the image is coupled out at a certain spatial angle through the grating structure in the coupling-out region, reaching the free-form mirror 3, then to the automotive windshield 4, and then reflected by the automotive windshield 4 to the eye position of the human head model 5, enabling the driver to see the navigation virtual image presented by the light on the road ahead, thus realizing the navigation function. Among them, the free-form lens 3 can be flipped according to the adjustment range of the eyebox.

[0069] Embodiment 2

[0070] To solve the problem of the complex design and high processing difficulty of the grating structure in the existing HUD system, this embodiment further optimizes the grating structure design of the coupling region of the optical waveguide. Specifically, in this embodiment, through calculation, the efficient transmission of the light beam within the optical waveguide and the deflection accuracy of the grating are ensured.

[0071] In this embodiment, the light beam generated by the optical engine is preliminarily shaped by the beam shaping element and then enters the coupling region with the grating structure. The design of the grating structure follows the following relationship:

[0072] ;

[0073] where θ0 is the deflection angle of the incident light of the grating, θ1 is the deflection angle of the outgoing light of the grating, is the tilt angle of the incident light of the grating, θ is the tilt angle of the grating output light, m is the diffraction order, λ is the wavelength of light, d is the grating constant, and n is the refractive index of the incident medium. Through this equation, the parameters of the grating can be accurately calculated to ensure that the deflection angle and tilt angle of the light beam when entering the optical waveguide meet the design requirements.

[0074] Furthermore, the parameter selection of the grating structure needs to consider the refractive index of the optical waveguide, the wavelength of the light beam, and the required deflection angle. For example, for a laser light source designed for a wavelength of 532 nm, a grating constant d of 1.5 μm, a refractive index n of 1.5, and a diffraction order m of 1 can be selected. This parameter combination can ensure total internal reflection transmission of the light beam in the optical waveguide while reducing light loss and aberration generation.

[0075] Furthermore, the coupling region of the optical waveguide can use surface relief gratings or volume holographic gratings. The specific selection of the grating type can be optimized according to different application scenarios and optical performance requirements. The manufacturing process of surface relief gratings is relatively mature and suitable for mass production; volume holographic gratings have higher diffraction efficiency and better optical performance and are suitable for high-end models or special application occasions.

[0076] Furthermore, the optimized design of the grating structure also includes fine adjustment of the grating period and grating depth. Through numerical simulation and experimental verification, the most suitable grating parameters can be determined to achieve the best light beam deflection effect and image quality. The optimization of the grating structure not only improves the coupling efficiency of the light beam but also reduces the size of the optical waveguide, making it more compact and miniaturized. It can be understood that the optimization of this embodiment is not only applicable to the HUD system of the present invention but can also be extended to other optical applications based on optical waveguides.

[0077] Through the optimization of the grating structure in this embodiment, the efficiency and accuracy of the optical waveguide HUD system in the light beam coupling and transmission process are improved, and the problem of difficult processing of the grating structure in the prior art is solved. Through accurate grating equation calculation and parameter optimization, not only the optical performance of the system is improved, but also the manufacturing cost is reduced, which is conducive to large-scale market promotion and application.

[0078] Embodiment 3

[0079] To solve the problem of single grating structure type and poor aberration correction effect in the existing HUD system, this embodiment optimizes the grating structure type in the coupling region of the optical waveguide. This embodiment uses surface relief gratings or volume holographic gratings and selects appropriate one-dimensional, two-dimensional, or super grating structures according to actual application requirements.

[0080] In this embodiment, after the light beam generated by the optical engine is preliminarily shaped by the beam shaping element, it enters the grating structure in the coupling region. The grating structure can be a surface relief grating or a volume holographic grating. Further, the grating structure can be a one-dimensional grating, a two-dimensional grating, or a metagrating to meet different requirements for beam expansion and deflection.

[0081] Further, the one-dimensional grating structure mainly expands the beam laterally, while the two-dimensional grating structure can achieve both lateral and longitudinal beam expansion. This design can ensure that the beam has an appropriate divergence angle when entering the optical waveguide, so as to achieve efficient total internal reflection transmission in the optical waveguide. The metagrating structure combines the advantages of one-dimensional and two-dimensional gratings and can achieve precise beam control and aberration correction in a more complex optical system. It should be understood that different types of grating structures are selected to meet the specific requirements for beam expansion and deflection in different application scenarios, thereby improving the applicability of the system.

[0082] Further, the coupling region and the decoupling region of the optical waveguide can both adopt the same or different grating structures. By using different types of gratings in the coupling region and the decoupling region, the coupling efficiency and transmission performance of the beam can be further optimized. For example, using a one-dimensional grating for lateral beam expansion in the coupling region and a two-dimensional grating for longitudinal beam expansion in the decoupling region, this combination can effectively improve the beam uniformity and image quality. It can be understood that the design of this multi-stage grating structure not only improves the optical performance of the system but also increases the complexity of the system. However, through reasonable process and material selection, the cost can be effectively controlled.

[0083] This embodiment improves the efficiency and accuracy of the optical waveguide HUD system in the process of beam expansion and deflection by optimizing the type and design of the grating structure, and solves the problems of single type of grating structure and poor aberration correction effect in the prior art. Through this embodiment, higher optical image quality and smaller device volume can be achieved, providing users with a clearer and more comfortable visual experience.

[0084] Embodiment Four

[0085] To solve the problems of single selection of the optical waveguide substrate material and low optical efficiency in the existing HUD system, this embodiment further optimizes the substrate material and thickness parameters of the optical waveguide. Specifically, in this embodiment, by adjusting the refractive index and thickness of the optical waveguide substrate, efficient light transmission in the waveguide and the realization of a large field of view are ensured.

[0086] In this embodiment, the light beam generated by the optical engine is preliminarily shaped by a beam shaping element and then enters the optical waveguide. The substrate material of the optical waveguide can be glass, resin or organic polymer crystal, and the specific selection depends on the required optical performance and manufacturing cost. Glass materials have a high refractive index and good optical transparency, and are suitable for high-precision optical systems; resin materials have a low manufacturing cost and high flexibility, and are suitable for mass production; organic polymer crystals have the optical performance of glass materials while having the advantage of higher light weight. Further, the refractive index range of the optical waveguide substrate is 1.4 to 2.8, and the specific value selection depends on the design parameters of the optical waveguide and the transmission requirements of the light beam.

[0087] Further, the thickness range of the optical waveguide substrate is 0.5 mm to 5 mm, and the specific value selection needs to consider the transmission efficiency of the optical waveguide and the miniaturization requirements of the device. For example, for an optical waveguide substrate with a thickness of 1 mm, the transmission angle of the light beam can be optimized by adjusting the refractive index of the substrate so that it undergoes total internal reflection transmission in the waveguide. It should be understood that the selection of the thickness and refractive index of the optical waveguide substrate has an important impact on the optical performance of the system, so detailed numerical simulations and experimental verifications are required during design.

[0088] Further, both the light coupling region and the light output region of the optical waveguide adopt a diffraction grating structure to ensure the deflection angle and efficiency of the light beam when entering and leaving the optical waveguide. By optimizing the substrate material and thickness, the transmission efficiency and image quality of the light beam can be significantly improved, and the generation of light loss and aberration can be reduced.

[0089] This embodiment improves the efficiency and image quality of the optical waveguide HUD system during the light beam transmission process by optimizing the material and thickness parameters of the optical waveguide substrate, and solves the problems of single selection of substrate materials and low optical efficiency in the prior art. It can achieve a smaller device volume and higher optical performance, providing a clearer and more reliable HUD display effect for users.

[0090] Embodiment Five

[0091] To solve the problem that the calculation of the flipping angle of the freeform mirror in the existing HUD system is complex and the accuracy is insufficient, this embodiment further optimizes the calculation method of the flipping angle of the freeform mirror. Specifically, in this embodiment, by introducing an accurate calculation formula, it is ensured that the freeform mirror can accurately flip according to the eye position of the driver, thereby expanding the viewing range of the eye box.

[0092] In this embodiment, the light beam generated by the optical engine is preliminarily shaped by a beam shaping element and then enters the optical waveguide. The light beam coupled out from the optical waveguide is subjected to field of view expansion and aberration correction through a freeform mirror. The flipping angle of the freeform mirror is calculated by the following formula:

[0093] ;

[0094] Among them, θ flip is the flipping angle of the free-form mirror, h eye is the height of the driver's eyes, h pivot is the height of the rotation axis of the free-form mirror, d mirror is the distance between the free-form mirror and the windshield. Through this formula, the flipping angle of the free-form mirror can be accurately calculated to ensure that clear HUD information can be provided at different eye positions of drivers.

[0095] Furthermore, the height h pivot of the rotation axis of the free-form mirror can be adjusted according to the design parameters of the optical waveguide to ensure the best deflection effect of the light beam when passing through the free-form mirror. The distance d mirror between the free-form mirror and the windshield also needs to be optimized according to the position of the windshield of the specific vehicle model to ensure that the light beam can be accurately reflected to the driver's eye position. It should be understood that the selection of these parameters directly affects the flipping accuracy of the free-form mirror and the display effect of the HUD.

[0096] Furthermore, the free-form mirror is designed using advanced free-form mirror processing technologies, such as numerical control grinding or high-precision injection molding, to ensure the surface accuracy and optical performance of the lens. By adjusting the flipping angle of the free-form mirror in real time, it can adapt to different eye positions and sitting postures of drivers, improving the user experience. It can be understood that this design not only increases the eye box range but also reduces the visual fatigue of drivers caused by frequent adjustment of head or body postures, enhancing driving comfort and safety.

[0097] This embodiment significantly improves the display effect of the optical waveguide HUD system at different eye positions of drivers by optimizing the flipping angle calculation method of the free-form mirror, solving the problems of complex flipping angle calculation and insufficient accuracy of the free-form mirror in the prior art. A larger eye box range can be achieved while ensuring the stability of the system.

[0098] Embodiment Six

[0099] To solve the problem that the flipping angle adjustment of the free-form mirror in the existing HUD system depends on manual operation and is not flexible, this embodiment further optimizes the flipping angle adjustment mechanism of the free-form mirror. Specifically, this embodiment automatically adjusts the flipping angle of the free-form mirror by detecting the driver's body posture and eye position in real time to ensure that drivers of different heights and body shapes can clearly see the HUD information.

[0100] In this embodiment, after the light beam generated by the optical engine is preliminarily shaped by the beam shaping element, it enters the optical waveguide. The light beam coupled out from the optical waveguide is subjected to field of view expansion and aberration correction through a freeform mirror. The flipping angle of the freeform mirror is adjusted in real time according to the driver's body posture and eye position. Specifically, a driver position sensor is included in the system, which can detect the driver's eye height and sitting posture in real time and transmit this information to the control circuit. The control circuit calculates the flipping angle of the freeform mirror using the formula of the foregoing embodiment based on the data input by the sensor.

[0101] Furthermore, the driver position sensor can be an optical-based sensor or an infrared-based sensor, and the specific choice depends on the required detection accuracy and cost. The installation position of the sensor is usually in front of the driver in the vehicle, such as above the steering wheel or in the dashboard area, and can accurately detect the changes in the driver's eye position and sitting posture. It should be understood that the choice of the sensor has an important impact on the real-time detection accuracy and response speed of the system, so detailed testing and verification are required during the design.

[0102] Furthermore, the control circuit can not only adjust the flipping angle of the freeform mirror according to the data input by the sensor, but also dynamically adjust the light source parameters according to the ambient light intensity and the complexity of the display content. For example, in the daytime or strong light environment, the control circuit can appropriately increase the brightness of the light source to ensure the clarity of the display information; in the nighttime or low light environment, the control circuit can moderately reduce the brightness of the light source to reduce light pollution and energy consumption. It can be understood that this multi-parameter dynamic adjustment mechanism further improves the adaptability of the system.

[0103] This embodiment improves the display effect of the optical waveguide HUD system at different driver eye positions by detecting and adjusting the flipping angle of the freeform mirror in real time, and solves the problems of manual adjustment and inflexibility in the prior art. Through the design of this embodiment, a larger eye box range can be achieved, improving the user experience, while ensuring the automatic adjustment function of the system.

[0104] Embodiment Seven

[0105] To solve the problems that the adjustment of beam brightness and color balance in the existing HUD system depends on manual operation and has poor adaptability, this embodiment further optimizes the adjustment mechanism of the control circuit for beam brightness and color balance. Specifically, this embodiment automatically adjusts the brightness and color balance of the beam by detecting the ambient light conditions in real time to ensure that the visual effect of the image can reach the best in different environments.

[0106] In this embodiment, after the light beam generated by the optical engine is preliminarily shaped by the beam shaping element, it enters the optical waveguide. The light beam coupled out from the optical waveguide is subjected to field of view expansion and aberration correction through a freeform mirror. The control circuit can detect the ambient light conditions in real time and dynamically adjust the brightness and color balance of the light beam according to these conditions. Specifically, an ambient light sensor is included in the system, which can detect the light intensity inside and outside the vehicle in real time and transmit this information to the control circuit. The control circuit adjusts the brightness and color balance of the light source using the following mechanism based on the data input by the sensor:

[0107] Specifically, the ambient light sensor can be a sensor based on a photodiode or a sensor based on a CMOS image sensor, and the specific choice depends on the required detection accuracy and cost. The installation position of the sensor is usually in front of the driver inside the vehicle, such as the edge of the windshield or the dashboard area, and can accurately detect changes in ambient light. It should be understood that the choice of the sensor affects the real-time detection accuracy and response speed of the system, so detailed testing and verification are required during design.

[0108] Furthermore, the control circuit includes a brightness adjustment module and a color balance adjustment module. The brightness adjustment module can adjust the brightness of the light source in real time according to the input data of the ambient light sensor. For example, in daytime or strong light environments, the brightness adjustment module can appropriately increase the brightness of the light source to ensure the clarity of the displayed information; in nighttime or low light environments, the brightness adjustment module can moderately reduce the brightness of the light source to reduce light pollution and energy consumption. The color balance adjustment module can adjust the color temperature, chromaticity, and color saturation of the light source in real time according to the complexity of the displayed content and the user's needs to ensure the visual effect of the image in different environments.

[0109] Furthermore, the control circuit can also be adjusted according to the user's input instructions. For example, the user can adjust the display mode of the HUD, such as switching to the daytime mode or the nighttime mode, through a touch screen or voice commands. The control circuit quickly adjusts the brightness and color balance of the light source according to the user's input instructions to provide a personalized display effect for the user.

[0110] Through the optimized design of the control circuit in this embodiment, the display effect of the optical waveguide HUD system under different environmental conditions can be significantly improved, and the problems of manual adjustment and poor adaptability in the prior art are solved. Through this embodiment, a more intelligent and automated brightness and color balance adjustment function can be achieved.

[0111] Embodiment Eight

[0112] To improve the volume and cost problems faced by the existing HUD optical aberration correction system when achieving a large field of view angle and a large eye box range, this embodiment proposes a HUD optical aberration correction system for implementing the HUD optical aberration correction method.

[0113] Specifically, the optical engine system uses a high-brightness LED light source, which has the characteristics of high photoelectric conversion efficiency and good color rendering, and can provide clear, bright and colorful images. To meet the requirements of the HUD system for high-resolution images, the optical engine system also integrates advanced microdisplay technologies, such as TFT-LCD displays with high refresh rates and high contrast ratios. The light beam generated by the light source is initially shaped and collimated by a beam shaping element, so that it has an appropriate divergence angle and spot size, which is convenient for subsequent optical waveguide coupling.

[0114] Furthermore, the optical waveguide element adopts a multi-layer diffractive-refractive hybrid two-dimensional optical waveguide design, including an input coupling region and an output coupling region. The input coupling region has a grating structure, which can efficiently deflect the light beam so that it undergoes total internal reflection transmission in the optical waveguide. The design of the grating structure follows the grating equation to ensure that the propagation angle of the light in the waveguide satisfies the total internal reflection condition. The waveguide substrate material is a high-refractive-index organic polymer crystal, with a thickness between 0.5 mm and 5 mm and a refractive index between 1.4 and 2.8. The waveguide bending and branching structures can achieve effective steering and distribution of the light beam, thereby reducing the volume of the system and improving the optical efficiency.

[0115] Furthermore, the aberration correction element includes a freeform mirror, which has a moderate area and a mature processing technology, reducing the production cost. The freeform mirror is located in the output coupling region of the optical waveguide and is used to expand the field of view and correct aberrations of the light beam coupled out from the optical waveguide. It should be understood that the freeform mirror can not only correct common aberration types, such as binocular parallax, distortion and MTF, but also flip the lens angle around the rotation axis according to the eye box adjustment range to ensure that the driver can obtain a clear image at different head positions. The aberration correction element also includes a binocular parallax correction module, a distortion correction module and an MTF optimization module, and these modules work together to ensure the quality of the finally displayed image.

[0116] Furthermore, the windshield serves as a reflecting surface to reflect the corrected light beam to form a navigation virtual image. The control circuit is connected to and controls the optical waveguide element, the aberration correction element, the light source system and the image generation unit to ensure the normal operation of the system and the coordinated work among various parts. The control circuit can adjust the aberration correction parameters, light source parameters and image display parameters in real time according to the environmental information detected by the sensor, the user's input instructions and the internal state of the system to adapt to different lighting conditions, display contents and user perspectives. It should be understood that the design of the control circuit takes into account the stability and reliability of the system under different conditions, ensuring that the HUD system can provide consistent high-quality images.

[0117] The benefits of this embodiment are that by optimizing the designs of the optical engine system, optical waveguide components, and aberration correction components, while achieving volume reduction and cost reduction, the image quality and driving safety are improved. In addition, the adjustable characteristics of the freeform mirror enable the system to adapt to the head positions of different drivers, enhancing the user experience.

[0118] Embodiment Nine

[0119] To improve the display effect of the HUD optical aberration correction device, especially to achieve naked-eye 3D display, this embodiment proposes a HUD optical aberration correction device. The correction device integrates a multi-layer optical waveguide structure and optical components on the basis of traditional optical waveguide components to support naked-eye 3D display. The multi-layer optical waveguide structure can accommodate more optical functional units, such as polarization volume holographic gratings for beam stratification and geometric array waveguides for beam steering. The integration of these structures not only improves the optical efficiency but also enables the system to generate 3D images with a sense of depth.

[0120] Furthermore, each layer structure in the optical waveguide has a specific function. For example, the first layer is used for the preliminary shaping and collimation of the beam, the second layer is used for the stratification and spatial distribution of the beam, and the third layer is used for the final beam expansion and field-of-view enhancement. It should be understood that the collaborative work of these layer structures can achieve efficient 3D image generation and transmission, ensuring that the finally displayed image has a high resolution and clarity. In addition, the multi-layer optical waveguide structure can also reduce the loss of the beam during transmission, improving the overall optical efficiency of the system.

[0121] Furthermore, the aberration correction component is further optimized in this embodiment, including a freeform mirror and other additional optical components. The freeform mirror is used for field-of-view expansion and aberration correction of the beam coupled out from the optical waveguide to ensure the image quality at different viewing angles. It can be understood that the design of the freeform mirror takes into account the special requirements of 3D images, such as different field-of-view angles and focal depths. In addition, a special 3D image optimization module is added to adjust the depth sense, contrast, and color balance of the image to ensure that the driver can obtain a realistic 3D visual experience.

[0122] Furthermore, the control circuit integrates more sensors and algorithms in this embodiment, which can detect the changes in the driving environment and the user's viewing angle in real time and dynamically adjust the aberration correction parameters, light source parameters, and image display parameters. For example, the control circuit can adjust the angle of the freeform mirror in real time according to the slight movement of the driver's head to ensure that the 3D image is always within the optimal viewing angle range of the driver. In addition, the control circuit can also automatically adjust the brightness and color of the light source according to the vehicle speed and ambient light conditions, so that the 3D image can remain clear and comfortable under different conditions.

[0123] The benefits of this embodiment are that through the multi-layer optical waveguide structure and optimized aberration correction elements, naked-eye 3D display is achieved, improving the display effect of the HUD system. The intelligent design of the control circuit enables the system to adjust parameters in real time according to different driving environments and user needs, ensuring that high-quality 3D images are always provided.

[0124] Embodiment Ten

[0125] To integrate the HUD optical aberration correction device into a vehicle, this embodiment further refines the design of the front windshield and the control circuit. The front windshield of the vehicle serves as the display surface of the HUD system and needs to have high optical reflectivity and low scattering characteristics to ensure the clarity and brightness of the navigation virtual image. The material of the front windshield is usually a multi-layer composite glass that blocks ultraviolet and infrared rays, and its surface is treated to reduce the interference of ambient light. The size and shape of the front windshield are designed considering the interior space of the vehicle and the driver's field of view, ensuring that the navigation virtual image can be presented at an appropriate distance and angle.

[0126] Furthermore, the control circuit in this embodiment integrates more environmental perception modules for real-time detection of environmental conditions inside and outside the vehicle, such as light intensity, temperature, humidity, and driving speed. The data from these sensors are used to dynamically adjust aberration correction parameters, light source parameters, and image display parameters. For example, the control circuit can adjust the light source brightness according to the external light intensity to ensure that the navigation virtual image maintains appropriate contrast and clarity both in bright daylight and at night. In addition, the control circuit can also adjust the display position and content of the navigation information in real time according to the driving speed and direction, ensuring that the driver can quickly and accurately obtain important information in different driving scenarios.

[0127] Furthermore, the control circuit also integrates a user input module for receiving driver instructions, such as operating through buttons on the steering wheel or a touch screen. The user input module can be used to adjust the display mode of the image, such as switching between normal mode and 3D mode. The control circuit will adjust the aberration correction element and light source parameters in real time according to the user's instructions to provide the best display effect. In addition, a user-defined setting function is added, such as adjusting the font size, color, and position of the navigation information to meet the personalized needs of different drivers.

[0128] Furthermore, the algorithm design of the control circuit is also optimized, especially for the generation and transmission of 3D images, to reduce calculation latency and improve the response speed of the images. The algorithm design takes into account the characteristics of the optical waveguide elements to ensure efficient beam transmission between different layers. In addition, the control circuit also integrates a fault detection and automatic recovery function, which can alarm in time and restore to the normal state when the system malfunctions, improving the reliability of the system.

[0129] The benefits of this embodiment are that through the optimization of the design of the front windshield and the control circuit, seamless integration of the HUD optical aberration correction device in the vehicle is achieved. The intelligence of the control circuit and the user-defined setting function enable the system to provide the best display effect according to different driving environments and user needs, improving driving safety and comfort.

[0130] In the above embodiments, the purpose, technical solutions, and beneficial effects of the present invention are further described in detail. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solutions of the present invention shall be included in the protection scope of the present invention.

Claims

1. A HUD optical aberration correction method, characterized in that: The steps of the correction method include: Generate a light beam through an LED light source or a laser light source, and adjust the brightness and color parameters of the LED light source or the laser light source through a control circuit to adapt to different display requirements and environmental conditions; The light beam is initially shaped and collimated by a beam shaping element until a suitable divergence angle and spot size are met to meet the requirements of the coupling element; The light beam enters the optical waveguide through an incoupling region having a grating structure, and the grating structure deflects the light beam so that the light beam is transmitted by total reflection in the optical waveguide until it reaches an outcoupling region; The coupled light beam coupled out from the optical waveguide passes through a free-form mirror to form a correction light beam for expanding the field of view and correcting aberrations. The free-form mirror flips according to the eye box adjustment range to ensure clear imaging at different eye positions of different drivers. The corrected light beam is reflected through the windshield into the driver's field of vision to form a navigation virtual image, so as to present navigation information on the road ahead to the driver; The control circuit detects environmental information, user input instructions and the internal state of the system in real time, and dynamically adjusts aberration correction parameters, light source parameters and image display parameters to optimize the display effect; The design of the grating structure in the coupling region of the optical waveguide is as follows: ； Among them, θ0 is the deflection angle of the incident light of the grating, θ1 is the deflection angle of the outgoing light of the grating, is the incident light tilt angle of the grating, is the tilt angle of the grating output light, m ​​is the diffraction order, λ is the wavelength of light, d is the grating constant, and n is the refractive index of the incident medium; The grating structure is a surface relief grating or a volume holographic grating, and the grating structure includes a one-dimensional grating, a two-dimensional grating or a super grating; The light beam after passing through the diffraction waveguide satisfies that the propagation angle of the light in the waveguide is greater than the Brewster angle: ； Where α is the propagation angle of the light in the waveguide, n b is the refractive index of the optical waveguide substrate, 1.4≤n b ≤2.8; The optical waveguide substrate is made of glass, resin or organic polymer crystal, and the thickness of the optical waveguide substrate is d b , 0.5mm≤d b ≤5mm; The flip angle of the free-form surface mirror is calculated by the following formula: ； Among them, θ flip is the flip angle of the free-form mirror, h eye is the height of the driver's eyes, h pivot is the rotation axis height of the free-form mirror, d mirror is the distance between the free-form mirror and the windshield.

2. The HUD optical aberration correction method according to claim 1, characterized in that: The flip angle of the free-form mirror is adjusted in real time according to the driver's body posture and eye position to ensure that drivers of different heights and body shapes can clearly see the HUD information.

3. The HUD optical aberration correction method according to claim 1, characterized in that: During the formation of the navigation virtual image, the brightness and color balance of the light beam are adjusted in real time by the control circuit to adapt to different ambient lighting conditions and ensure the visual effect of the image.

4. A HUD optical aberration correction system, used to implement the HUD optical aberration correction method according to any one of claims 1 to 3, characterized in that: The correction system comprises: An optical machine, which includes a high-brightness LED or laser light source, for generating a light beam and adjusting the brightness and color parameters of the light beam, for providing a clear, bright and colorful image; An optical waveguide, comprising an incoupling region and an outcoupling region, wherein the incoupling region has a grating structure and can deflect a light beam to perform total reflection transmission in the optical waveguide; An aberration correction element, comprising a free-form surface mirror, for expanding the field of view and correcting the aberration of the light beam coupled out from the optical waveguide, wherein the free-form surface mirror flips the lens angle around the rotation axis according to the eye box adjustment range to achieve clear imaging within a large eye box range; A windshield, used to reflect the corrected light beam to form a navigation virtual image; A control circuit, connected to and controlling the optical waveguide element, the aberration correction element, the light source system and the image generation unit, for controlling and operating the correction system; The aberration correction element further comprises: Binocular parallax correction module, used to optimize binocular parallax; A distortion correction module, used to correct the distortion in the optical system; The MTF optimization module is used to optimize the modulation transfer function of the correction system to improve the resolution and clarity of the image.

5. A HUD optical aberration correction device, characterized in that: The correction device includes the HUD optical aberration correction system as described in claim 4, and the correction device also includes a naked-eye 3D implementation system, which is used for naked-eye 3D display by integrating a multi-layer optical waveguide structure and optical components in the optical waveguide element.

6. A vehicle, characterized in that: The vehicle comprises the HUD optical aberration correction device according to claim 5, and the vehicle further comprises: The front windshield serves as a display surface of the correction device and is used to reflect the light beam to form a navigation virtual image; The control circuit is used to detect environmental information, user input instructions and the internal state of the system in real time, and dynamically adjust aberration correction parameters, light source parameters and image display parameters to optimize the display effect.

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