A head-up display system and a display method thereof

Abstract

The embodiment of the application provides a head-up display system and a display method thereof, and belongs to the technical field of display. The head-up display system comprises: an image generation unit; a reflective optical assembly comprising at least one deformable reflective element; a lateral curvature adjustment group and a longitudinal curvature adjustment group, both of which are arranged on the back reflection surface side of the deformable reflective element, the lateral curvature adjustment group is arranged along the lateral direction of the deformable reflective element, and the lateral curvature adjustment group is used for applying stress to adjust the lateral curvature radius of the deformable reflective element, so that the head-up display system realizes continuous zooming; the longitudinal curvature correction group is arranged along the longitudinal direction of the deformable reflective element, and the longitudinal curvature correction group is used for applying compensation stress to correct the longitudinal curvature radius, so as to reduce the ghosting value of the image. Through dynamic adjustment of the lateral curvature radius and the longitudinal curvature radius of the deformable reflective element, the embodiment of the application realizes wide-range continuous zooming of the virtual image distance, while suppressing ghosting distortion.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of display, and more particularly, to a head-up display system and a display method of the head-up display system. BACKGROUND

[0002] With the development of automotive intelligence, the head-up display system (HUD) has become an important configuration to improve driving safety and convenience. The HUD projects vehicle condition information (such as vehicle speed, engine speed, navigation prompts, etc.), real scene intersection information, driving assistance information, etc. onto the windshield glass, so that the driver can obtain key information without lowering his head, thereby reducing visual transfer and reducing the risk of accidents.

[0003] In the actual application of the HUD, the user's demand for dynamic adjustment of the virtual image distance (VID) is increasingly prominent. For example, in a high-speed driving scenario, the driver wants the virtual image distance to be farther (such as more than 10 m) to reduce visual fatigue and conform to the focusing habit of the human eye for long-distance targets; in a low-speed or congested scenario, the driver wants the virtual image distance to be closer (such as within 2 m) to quickly obtain information in the near distance (such as intersection turning prompts, pedestrian warnings, etc.).

[0004] The existing HUD adjusts the virtual image distance by moving the position of the reflecting mirror or the liquid lens through a mechanical structure, changing the optical path length to adjust the virtual image distance. When the virtual image distance changes in a large range, the virtual image distance between the inner surface reflection and the outer surface reflection of the windshield glass increases, resulting in ghosting exceeding the acceptable threshold of the human eye, which significantly affects the visual experience, especially in strong light environments.

[0005] Therefore, there is a need to provide a new technical solution to solve the above technical problems. SUMMARY

[0006] The purpose of the present application is to provide a new technical solution of a head-up display system and a display method of the head-up display system, aiming to solve the technical problem that the existing solution cannot continuously change the virtual image distance while ensuring ghosting suppression and imaging quality in the full distance range.

[0007] In a first aspect, embodiments of the present application provide a head-up display system. The head-up display system comprises:

[0008] an image generation unit configured to generate and emit display light rays carrying image information;

[0009] a reflective optical assembly comprising at least one deformable reflective element, a reflective surface of the deformable reflective element being configured to receive and reflect the display light rays;

[0010] a lateral curvature adjusting group arranged on the back reflecting surface side of the deformable reflecting element, the lateral curvature adjusting group arranged along the lateral direction of the deformable reflecting element, the lateral curvature adjusting group configured to apply stress to adjust the lateral curvature radius of the deformable reflecting element, so that the head-up display system realizes continuous zooming;

[0011] a longitudinal curvature correcting group arranged on the back reflecting surface side of the deformable reflecting element, the longitudinal curvature correcting group arranged along the longitudinal direction of the deformable reflecting element, the longitudinal curvature correcting group configured to apply compensating stress to correct the longitudinal curvature radius of the deformable reflecting element in case that the longitudinal curvature radius deviates from a preset threshold, so as to reduce the image ghosting value.

[0012] Optionally, the reflecting optical assembly comprises one deformable reflecting element, the lateral curvature adjusting group is arranged along the lateral direction of the deformable reflecting element, and the longitudinal curvature correcting group is arranged along the longitudinal direction of the deformable reflecting element.

[0013] Optionally, the reflecting optical assembly comprises at least two deformable reflecting elements, the lateral curvature adjusting group is arranged along the lateral direction of one of the deformable reflecting elements, and the longitudinal curvature correcting group is arranged along the longitudinal direction of another of the deformable reflecting elements.

[0014] Optionally, the lateral curvature adjusting group comprises at least two first adjusting units, and the at least two first adjusting units are arranged along the lateral center line of the deformable reflecting element.

[0015] Optionally, the longitudinal curvature correcting group comprises at least two second adjusting units, and the at least two second adjusting units are arranged along the longitudinal center line of the deformable reflecting element.

[0016] Optionally, the longitudinal curvature correcting group comprises six second adjusting units, and the six second adjusting units are divided into three groups of second adjusting units, and the arrangement of the three groups of second adjusting units satisfies the following conditions:

[0017] The first group of second adjusting units is arranged along the longitudinal center line of the deformable reflecting element;

[0018] The second group of second adjusting units is symmetrically distributed on the longitudinal two sides of one of the first adjusting units, and the third group of second adjusting units is symmetrically distributed on the longitudinal two sides of another of the first adjusting units.

[0019] Optionally, the first adjusting units and the second adjusting units are actuators.

[0020] Optionally, the head-up display system further comprises a detection unit configured to obtain a ghosting value of the image displayed by the head-up display system.

[0021] In a case where the ghosting value deviates from a preset threshold, a compensation stress is applied by the longitudinal curvature correction group to correct a longitudinal curvature radius of the deformable reflective element, so as to adjust the ghosting value of the image displayed by the head-up display system.

[0022] Optionally, the reflective optical assembly further comprises a fixed mirror arranged between the image generation unit and the deformable reflective element, configured to adjust an initial propagation direction of the display light.

[0023] In a second aspect, the embodiments of the present application further provide a display method of a head-up display system. The method is applied to the head-up display system as described in the first aspect, and the method comprises the following steps:

[0024] obtaining preset information;

[0025] generating corresponding display image information according to the preset information;

[0026] calculating a virtual display distance matched with the image information based on the image information;

[0027] controlling a transverse curvature adjustment group in the head-up display system to adjust a transverse curvature radius of the deformable reflective element to a target value according to the virtual display distance;

[0028] obtaining a longitudinal curvature radius of the deformable reflective element in real time, and determining whether the longitudinal curvature radius is within a preset threshold;

[0029] if the longitudinal curvature radius is within the preset threshold, controlling the head-up display system to project the display image information at the virtual display distance;

[0030] if the longitudinal curvature radius is not within the preset threshold, controlling a longitudinal curvature correction group to dynamically compensate the longitudinal curvature of the deformable reflective element until the longitudinal curvature radius returns to the preset threshold;

[0031] controlling the head-up display system to project the display image information at the virtual display distance in a case where the longitudinal curvature radius is within the preset threshold.

[0032] Optionally, the longitudinal curvature radius is determined according to an eyebox position.

[0033] One technical effect of the present application is that:

[0034] In the technical scheme provided by the head-up display system, the transverse curvature radius and the longitudinal curvature radius of the deformable reflective element are dynamically adjusted, so that the wide-range continuous zoom of the virtual image distance (VID) is realized, and ghosting distortion is inhibited.

[0035] Other features of the present specification, and the advantages thereof over other solutions, will become more apparent from the following detailed description of exemplary embodiments of the present specification, with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0036] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present specification and, together with the description, serve to explain the principles of the present specification.

[0037] Figure 1 A structure schematic diagram of a head-up display system provided by an embodiment of the present application is shown.

[0038] Figure 2 A structure schematic diagram of a deformable reflective element provided with a transverse curvature adjusting group and a longitudinal curvature correcting group is shown.

[0039] Figure 3 A flow chart of a display method of a head-up display system provided by an embodiment of the present application is shown.

[0040] Explanation of reference signs:

[0041] 1, image generating unit; 2, reflective optical assembly; 21, fixed mirror; 22, deformable reflective element; 3, transverse curvature adjusting group; 31, first adjusting unit; 4, longitudinal curvature correcting group; 41, second adjusting unit; 5, windshield. DETAILED DESCRIPTION

[0042] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. Note that the relative arrangement, numerical expressions, and numerical values of components and steps set forth in these embodiments are not limiting to the scope of the present application unless otherwise specifically stated.

[0043] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting to the scope of the present application or its applications or uses.

[0044] Techniques and equipment known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the specification where appropriate.

[0045] In all examples shown and discussed herein, any specific value should be interpreted as merely illustrative, and not as a limitation. Thus, other examples of the exemplary embodiments can have different values.

[0046] It should be noted that like numerals and letters refer to like items throughout the several views, as such, once an item is defined in one view, it need not be discussed further in subsequent views.

[0047] The embodiments of the present application provide a head-up display system. Referring to Figure 1 and Figure 2 The head-up display system comprises an image generation unit 1 configured to generate and emit display light rays carrying image information.

[0048] A reflective optical assembly 2 comprising at least one deformable reflective element 22 having a reflective surface configured to receive and reflect the display light rays.

[0049] A lateral curvature adjustment group 3 disposed on a back reflective surface side of the deformable reflective element 22, the lateral curvature adjustment group 3 arranged along a lateral direction of the deformable reflective element 22, the lateral curvature adjustment group 3 configured to apply stress to adjust a lateral curvature radius of the deformable reflective element 22 to enable continuous zooming of the head-up display system. A longitudinal curvature correction group 4 disposed on the back reflective surface side of the deformable reflective element 22, the longitudinal curvature correction group 4 arranged along a longitudinal direction of the deformable reflective element 22, the longitudinal curvature correction group 4 configured to apply compensating stress to correct a longitudinal curvature radius of the deformable reflective element 22 to reduce ghosting value in case the longitudinal curvature radius deviates from a preset threshold.

[0050] In the embodiments of the present application, the lateral direction of the deformable reflective element 22 is a length direction of the deformable reflective element 22. The longitudinal direction of the deformable reflective element 22 is a height direction of the deformable reflective element 22.

[0051] The embodiments of the present application provide a head-up display system (HUD) which realizes wide-range continuous zooming of a virtual image distance (VID) by dynamically adjusting the curvature of a deformable reflective element 22, while suppressing ghosting distortion.

[0052] Specifically, the image generation unit 1 (PGU) is configured to generate display light rays carrying image information (such as navigation, vehicle speed, etc.) and project them to the reflective optical assembly 2.

[0053] The image generation unit 1 is usually a micro projector (such as DLP or LCoS technology), a liquid crystal display screen, etc., and the image generation unit 1 emits display light rays carrying image information.

[0054] The reflective optical assembly 2 comprises at least one deformable reflective element 22 (such as a flexible mirror) configured to receive and reflect the display light rays.

[0055] For example, in the case that the reflective optical assembly 2 includes one deformable reflective element 22, the reflective surface of the deformable reflective element 22 receives the display light and reflects the display light to the vehicle windshield, and finally enters the human eye to form a virtual image. The left eye and the right eye of the driver are generally in a horizontal line or close to the horizontal direction. In this case, the length direction of the reflective optical assembly 2, that is, the transverse direction, is adapted thereto.

[0056] For example, in the case that the reflective optical assembly 2 includes two deformable reflective elements 22, the reflective surface of one deformable reflective element 22 receives the display light and reflects the display light to the other deformable reflective element 22, and the reflective surface of the other deformable reflective element 22 receives the display light and reflects the display light to the vehicle windshield, and finally enters the human eye to form a virtual image.

[0057] For example, the deformable reflective element 22 can include an elastic substrate and a reflective layer. The elastic substrate is made of a flexible or elastic material, and the flexible material includes polydimethylsiloxane (PDMS) or polyethylene terephthalate (PET), polycarbonate (PC), etc. The elastic material includes thermoplastic polyurethane elastomer (TPU), etc. The reflective layer is deposited on the surface of the elastic substrate, and the reflective layer includes an aluminum film or a dielectric multilayer film. The reflectivity of the reflective layer is not less than 80% in the visible light band.

[0058] In the embodiments of the present application, with reference to Figure 1 and Figure 2 The transverse radius of curvature of the deformable reflective element 22 can be dynamically adjusted to change the length of the virtual image imaging light path, so that the imaging distance of the image entering the left eye and the right eye of the human eye changes, thereby realizing continuous zoom of the virtual image distance (VID). However, in the process of adjusting the transverse radius of curvature, due to the non-ideality of the material properties or stress distribution, the longitudinal radius of curvature of the deformable reflective element 22 can change slightly.

[0059] Through the design of the longitudinal curvature correction group 4, when the transverse radius of curvature is adjusted, if the change amount of the longitudinal radius of curvature is within a preset threshold (for example, the change amount of the longitudinal radius of curvature ≤1‰), it can be considered that the longitudinal radius of curvature has hardly changed. In this case, the longitudinal imaging distance of the deformable reflective element 22 remains stable. Specifically, the adjustment of the transverse radius of curvature only causes a slight change in the lens transverse sagitta (Sagitta), and only the slight change in the lens transverse sagitta (Sagitta) can cause a slight shift of the surface position of the deformable reflective element 22, but the longitudinal radius of curvature remains unchanged, so the change of the longitudinal imaging distance can be ignored. In this embodiment, the preset threshold specifically refers to the threshold corresponding to the change amount of the longitudinal radius of curvature of the deformable reflective element 22.

[0060] In view of the fact that the longitudinal imaging distance is basically maintained constant, the virtual image distance generated by the reflection of the inner and outer surfaces of the windshield 5 can be kept relatively stable relative to the angle of view of the human eye, which is the root cause of the ghosting phenomenon. Based on this characteristic, the ghosting value can be effectively controlled within a threshold range that is imperceptible to the human eye, for example, ghosting value ≤ 3 arc minutes. This design effectively ensures the stability of the longitudinal imaging quality during the continuous zooming of the virtual image distance, successfully avoiding the problem of ghosting deterioration caused by changes in the longitudinal curvature radius. Conversely, if the virtual image distance is shortened, the angle of view of the virtual image distance relative to the human eye will increase, thereby causing the ghosting value to increase, which will adversely affect the overall display effect.

[0061] When the lateral curvature radius is adjusted, if the change in the longitudinal curvature radius is not within the preset range (for example, the change in the longitudinal curvature radius > 1 ‰ or more), it is considered that the longitudinal curvature radius has changed due to the adjustment of the lateral curvature radius. In this case, when the longitudinal curvature radius changes significantly, the distance between the virtual images formed by the reflection of the inner and outer surfaces of the windshield 5 will change. Due to the change in the virtual image distance, from the perspective of the human eye, the originally stable ghosting condition will change. Once the ghosting condition changes beyond a certain range, ghosting distortion will occur, causing the observer to see a blurred image, ghosting confusion, and other problems, which seriously affect the visual experience and the accuracy of the imaging. The embodiments of the present application ensure that the longitudinal curvature radius is always in a stable state through real-time correction of the longitudinal curvature correction group 4, control the ghosting value below the threshold value imperceptible to the human eye (for example, ≤ 3 arc minutes), thereby maintaining high-quality imaging effects.

[0062] In addition, if the ghosting exceeds the threshold value due to errors in the windshield 5 or other components, the longitudinal curvature radius can be actively controlled to ensure that the longitudinal curvature radius is always in a stable state, the ghosting value is controlled below the threshold value imperceptible to the human eye (for example, ≤ 3 arc minutes), thereby maintaining high-quality imaging effects.

[0063] For example, the longitudinal curvature correction group 4 calculates the required compensation stress according to the change in the longitudinal curvature radius of the deformable reflective element 22, and applies a reverse stress through an electromagnetic driving unit (or other driving mode) to offset the effect of lateral curvature adjustment on the longitudinal curvature radius, so that it returns to within the preset threshold value, ensuring that the longitudinal curvature radius is always in a stable state. Due to the stability of the longitudinal curvature radius, the virtual image distance formed by the reflection of the inner and outer surfaces of the windshield 5 remains unchanged relative to the angle of view of the human eye, the ghosting value is effectively suppressed, and the imaging quality of the head-up display system always meets the design requirements.

[0064] For example, the preset threshold value can be determined in the following way:

[0065] Based on the designed HUD physical object or design model, image quality simulation of a human eye vision model is performed to determine a mapping relationship between the longitudinal curvature radius and the ghosting value.

[0066] The preset threshold value can be a longitudinal curvature radius interval corresponding to a change of 0.2 angular minutes in the ghosting value.

[0067] In the embodiments of the present application, the lateral curvature adjustment group 3 and the longitudinal curvature correction group 4 work cooperatively to dynamically adjust the lateral curvature radius and the longitudinal curvature radius, so as to ensure that the imaging quality (including ghosting distortion, definition, etc.) always meets the design requirements while the virtual image distance is continuously zoomed.

[0068] In an optional embodiment of the present application, the head-up display system can further include a control unit in communication connection with the lateral curvature adjustment group 3 and the longitudinal curvature correction group 4, and the control unit is configured to control the lateral curvature adjustment group 3 and the longitudinal curvature correction group 4.

[0069] The head-up display system can further include a sensor, such as an FBG (Fiber Bragg Grating) sensor, which is configured to detect in real time whether the change amount of the longitudinal curvature radius exceeds a threshold range. The control unit dynamically adjusts the lateral curvature radius and the longitudinal curvature radius according to the real-time feedback data of the FBG sensor, so as to ensure that the imaging quality (including ghosting distortion, definition, etc.) always meets the design requirements while the virtual image distance is continuously zoomed.

[0070] In another specific embodiment, the deformable reflective element 22 further includes a bracket, and the lateral curvature adjustment group 3 and the longitudinal curvature correction group 4 are located on the back reflective surface side of the deformable reflective element 22. One side of the lateral curvature adjustment group 3 is connected to the deformable reflective element 22, and the other side of the lateral curvature adjustment group 3 is fixedly connected to the bracket.

[0071] In a specific embodiment of the present application, referring to Figure 1 , the reflective optical assembly 2 includes one deformable reflective element 22, the lateral curvature adjustment group 3 is arranged along the lateral direction of the deformable reflective element 22, and the longitudinal curvature correction group 4 is arranged along the longitudinal direction of the deformable reflective element 22.

[0072] In this embodiment, the reflective optical assembly 2 includes one deformable reflective element 22, which is configured to receive display light emitted by the image generation unit 1 and reflect the display light to the vehicle windshield to form a virtual image. For example, the reflective optical assembly 2 only includes one deformable reflective element 22, and the optical architecture of the reflective optical assembly 2 is simple.

[0073] In this embodiment, the lateral curvature radius of the deformable reflective element 22 is dynamically adjusted by the lateral curvature adjustment group 3, and the virtual image imaging light path length changes accordingly. The virtual image distance can be continuously adjusted within a wide range (e.g., 2 m to 20 m) to adapt to different driving scenarios (e.g., urban congested road sections and highways).

[0074] The lateral curvature adjustment may cause a change in the longitudinal curvature radius, which in turn causes ghosting distortion (because the distance between the virtual images reflected by the inner and outer surfaces of the windshield 5 increases relative to the angular aperture of the human eye). The longitudinal curvature correction group 4 in the embodiments of the present application limits the change in the longitudinal curvature radius to within a preset threshold (e.g., ≤1‰) through real-time monitoring and feedback control, ensures that the ghosting value is below the threshold value (e.g., ≤3 angular minutes) that can be perceived by the human eye, avoids the curvature coupling problem caused by mechanical fixation in traditional HUD systems, suppresses ghosting, and significantly improves the imaging quality.

[0075] In this embodiment, the single deformable reflective element 22 design reduces the number of optical elements, reducing the system's sensitivity to mechanical errors. The cooperative work of the lateral curvature adjustment group 3 and the longitudinal curvature correction group 4 ensures the stability and reliability of the system in long-term use. At the same time, it ensures that the virtual image distance can be continuously adjusted within a wide range.

[0076] In another specific embodiment of the present application, the reflective optical assembly 2 includes at least two deformable reflective elements 22, the lateral curvature adjustment group 3 is arranged along the lateral direction of one of the deformable reflective elements 22, and the longitudinal curvature correction group 4 is arranged along the longitudinal direction of the other deformable reflective element 22.

[0077] In this embodiment, the reflective optical assembly 2 includes at least two independently deformable reflective elements 22, each of which can be individually or cooperatively adjusted in curvature radius. For example, the reflective optical assembly 2 includes two deformable reflective elements 22, which include a first deformable reflective element and a second deformable reflective element. The first deformable reflective element assumes the main function of light path adjustment (e.g., virtual image distance (VID) zoom). The second deformable reflective element 22 assists the first deformable reflective element 22 in optimizing the imaging quality (e.g., suppressing ghosting).

[0078] In this embodiment, through the division and cooperation of the two deformable reflective elements 22, the head-up display system can simultaneously achieve the effects of continuous zooming of the virtual image distance and optimization of the imaging quality.

[0079] For example: The first deformable reflective element adjusts the VID, and the second deformable reflective element compensates for the aberration or ghosting caused by the adjustment of the first deformable reflective element, thereby improving the overall imaging quality.

[0080] Compared with the single-reflection-element design, the multi-reflection-element combination can expand the freedom of light path adjustment, realize a wider range of virtual image distance adjustment, and adapt to more complex driving scene requirements.

[0081] In addition, the longitudinal curvature correction group 4 of the second deformable reflection element can compensate for the longitudinal curvature coupling effect caused by the transverse curvature adjustment in real time independently of the adjustment process of the first deformable reflection element.

[0082] For example, when the transverse curvature radius of the first deformable reflection element is adjusted from 1000 mm to 2000 mm, the longitudinal curvature correction group 4 of the second deformable reflection element can limit the change in the longitudinal curvature radius to within 2%, ensuring that the virtual image value almost does not change, or ≤3 angular minutes.

[0083] This embodiment avoids the coupling problem of curvature adjustment and correction in the single-reflection-element design, improves the stability and imaging quality of the system, and ensures that the virtual image distance can be continuously adjusted within a wide range.

[0084] In the embodiments of the present application, with reference to Figure 1 The transverse curvature adjustment group 3 includes at least two first adjustment units 31, and the at least two first adjustment units 31 are arranged at intervals along the transverse center line of the deformable reflection element 22.

[0085] In this embodiment, the transverse curvature adjustment group 3 includes at least two first adjustment units 31 (such as piezoelectric actuators, shape memory alloy drivers, etc.). The at least two first adjustment units 31 are arranged at intervals along the transverse center line (i.e., the central axis perpendicular to the display light propagation direction) of the deformable reflection element 22.

[0086] Through the synergistic action of the plurality of first adjustment units 31, non-uniform stress is applied in the transverse direction of the deformable reflection element 22, so as to adjust the transverse curvature radius thereof. In addition, the first adjustment units 31 arranged at intervals can independently control the stress size at different positions, form a spatially non-uniform stress field, and realize more accurate curvature adjustment.

[0087] In this embodiment, the interval arrangement of the plurality of first adjustment units 31 makes the stress distribution more flexible, and the change in the transverse curvature radius of the deformable reflection element 22 can be accurately controlled.

[0088] Exemplarily, the transverse curvature adjustment group 3 includes two first adjustment units 31, and the two first adjustment units 31 are symmetrically distributed in the transverse direction of the deformable reflection element 22.

[0089] In the embodiments of the present application, with reference to Figure 2The longitudinal curvature correction group 4 comprises at least two second adjusting units 41, which are arranged along the longitudinal center line of the deformable reflecting element 22.

[0090] In this embodiment, by arranging the at least two second adjusting units 41 along the longitudinal center line, non-uniform and localized correction of the longitudinal curvature of the deformable reflecting element 22 is achieved, thereby suppressing the ghost from becoming larger. For example, when the lateral curvature adjusting group 3 changes the lateral curvature of the reflecting mirror, the stress distribution of the reflecting mirror material will cause the longitudinal curvature coupling to change (for example, lateral stretching causes longitudinal micro-concave), resulting in the ghost becoming larger. By arranging the second adjusting units 41, the deviation of the longitudinal curvature can be compensated for.

[0091] For example, a smaller stress is applied in the central region of the reflecting mirror, and a larger stress is applied in the edge region, thereby compensating for the sudden change in the edge curvature caused by lateral adjustment.

[0092] In this embodiment, the lateral curvature adjusting group 3 and the longitudinal curvature correction group 4 are arranged orthogonally in space (the lateral group is distributed along the lateral center line, and the longitudinal group is distributed along the longitudinal center line). When the lateral curvature adjusting group 3 adjusts the lateral curvature, the longitudinal curvature correction group 4 can monitor the change in the longitudinal curvature in real time (for example, by using FBG optical fiber grating sensors), dynamically adjust the driving signal of the second adjusting unit 41, suppress the ghost distortion to ≤3 angular minutes (below the threshold value of human eye perception), and reduce the image ghost value.

[0093] In a specific embodiment, with reference to Figure 2 The longitudinal curvature correction group 4 comprises six second adjusting units 41, which are divided into three groups of second adjusting units 41, and the arrangement of the three groups of second adjusting units 41 satisfies the following conditions:

[0094] The first group of second adjusting units 41 is arranged along the longitudinal center line of the deformable reflecting element 22;

[0095] The second group of second adjusting units 41 is symmetrically distributed on the longitudinal two sides of one of the first adjusting units 31, and the third group of second adjusting units 41 is symmetrically distributed on the longitudinal two sides of the other first adjusting unit 31.

[0096] In this embodiment, the first group of second adjusting units 41 is arranged along the longitudinal center line, and is responsible for the basic correction of the global longitudinal curvature of the deformable reflecting element 22, thereby compensating for the overall longitudinal deformation caused by the lateral curvature adjustment.

[0097] The second group of second adjustment units 41 and the third group of second adjustment units 41 are symmetrically distributed on the longitudinal sides of the two first adjustment units 31, finely compensating the local stress applied to the lateral adjustment unit (first adjustment unit 31) and suppressing edge curvature mutation.

[0098] In this embodiment, through the synergistic effect of the three groups of second adjustment units 41, a center-edge gradient stress field is formed: the stress density in the center area (first group) is low to avoid excessive constraint; the stress density in the edge area (second group / third group) is high to compensate for the edge warping caused by lateral adjustment.

[0099] Exemplarily, the second group of second adjustment units 41 and the third group of second adjustment units 41 are symmetrically distributed on the two sides of the lateral adjustment unit. When the lateral adjustment unit applies a tensile stress, the mirror edges on the longitudinal sides may be slightly convex due to the Poisson effect. Through the compression stress compensation of the second group / third group of second adjustment units 41, the edge curvature radius deviation can be controlled within ±1‰.

[0100] In this embodiment, through the division arrangement of the three groups of second adjustment units 41, high-precision adjustment of longitudinal curvature correction is achieved, avoiding the curvature coupling problem caused by mechanical fixation in traditional HUD systems, suppressing ghosting rate, and significantly improving imaging quality.

[0101] Preferably, the second adjustment unit 41 is a brake, and by adjusting the displacement amount of the three groups of second adjustment units 41, the longitudinal curvature radius of the deformable reflective element 22 can be changed. Further preferably, the displacement amounts adjusted by the six second adjustment units 41 included in the three groups of second adjustment units 41 are equal.

[0102] In an optional embodiment, the head-up display system further comprises a storage unit for storing a ghosting value of the image displayed by the head-up display system detected by an external device.

[0103] In the case where the stored ghosting value deviates from a set threshold value, a compensation stress is applied by the longitudinal curvature correction group 4 to correct the longitudinal curvature radius of the deformable reflective element 22, and the ghosting value of the image displayed by the head-up display system is adjusted.

[0104] Exemplarily, the external device can be an image sensor, a light intensity sensor, or a phase difference measurement sensor, etc.

[0105] In this embodiment, to accurately judge the imaging quality of the image displayed by the head-up display system, a double threshold limiting method (a preset threshold value corresponding to the longitudinal curvature radius of the deformable reflective element 22, and a set threshold value corresponding to the ghosting value) can be used. By setting two different levels of threshold values, the imaging quality related parameters are comprehensively evaluated, so that the judgment result of the imaging quality is more accurate.

[0106] In combination with the specific structure of the longitudinal curvature correction group 4, the method for determining the ghost compensation according to the ghost value includes the following steps:

[0107] 1) Ghost value detection and initial evaluation

[0108] The ghost value Gy of the HUD display image is actively collected by an external device, and the initial parameters of the deformable reflective element 22 (such as the material elastic modulus, the Poisson's ratio) and the optical parameters of the HUD imaging lens group (such as the focal length, the light path angle) are combined, based on a preset mapping relationship table or a theoretical calculation model (such as a stress-curvature coupling model based on finite element analysis), to determine the initial value of the longitudinal curvature radius of the deformable reflective element 22 ΔRz0.

[0109] 2) Dynamic adjustment of longitudinal curvature radius

[0110] According to the calculated ΔRz0, the longitudinal curvature correction group arranged on the deformable reflective element 22 is adjusted (for example, the displacement amounts of the three sets of second adjustment units 41 are simultaneously adjusted). During the adjustment process, the change amount of the longitudinal curvature radius of the deformable reflective element 22 is monitored in real time (such as by a laser interferometer or an FBG optical fiber grating sensor) to ensure the adjustment accuracy.

[0111] 3) Closed-loop verification of ghost compensation

[0112] The ghost value Gy' of the HUD display image is measured again by an external device, and if the set threshold is met, it is determined that the ghost compensation is completed; otherwise, the difference between the current ghost value Gy' and the initial value Gy is taken as a new input, the longitudinal curvature radius adjustment amount ΔRzi (i is the iteration number) is iteratively calculated, and step 2) is repeated until the convergence condition (such as the iteration number ≤ 5 times or |Gy'-Gy|≤0.1 angular minute) is met.

[0113] For example, the existing HUD adjusts the eyebox up and down by rotating the mirror to meet the needs of drivers of different heights. Because the windshield glass 5 has a certain curvature, the size of the virtual image viewed by the driver is different when the eyebox is located at different positions. A wedge-shaped film is added inside the windshield glass 5, which is thicker at the top and thinner at the bottom to weaken the ghosting. After the angle of the windshield wedge-shaped film is determined, generally, the ghosting is smallest when the eyebox is located in the middle position. The ghosting becomes larger when the eyebox is located at the highest and lowest positions.

[0114] In an optional embodiment, the present embodiment can effectively weaken the ghosting of the upper and lower eyeboxes. The ghost compensation method further includes the following steps:

[0115] 1) Center eyebox ghost value detection and compensation

[0116] The ghost value Gy1 of the HUD display image is actively collected by an external device, and the longitudinal radius of curvature of the deformable reflective element 22 is adjusted according to the detected ghost value Gy1, so that the ghost value Gy1 is minimized or less than a set threshold. At this time, the longitudinal radius of curvature of the deformable reflective element 22 corresponding to the minimum value of Gy1 is R0 (the initial value of the longitudinal radius of curvature);

[0117] 2) Upper and lower eyebox ghost value detection compensation

[0118] The ghost value Gy2 (the ghost value corresponding to the upper eyebox) of the HUD display image is actively collected by an external device, and the longitudinal radius of curvature of the deformable reflective element 22 is adjusted according to the detected ghost value Gy2, so that the ghost value Gy2 is minimized or less than a set threshold. At this time, the longitudinal radius of curvature of the deformable reflective element 22 corresponding to the minimum value of Gy2 is R1 (the initial value of the longitudinal radius of curvature);

[0119] The ghost value Gy3 (the ghost value corresponding to the upper eyebox) of the HUD display image is actively collected by an external device, and the longitudinal radius of curvature of the deformable reflective element 22 is adjusted according to the detected ghost value Gy3, so that the ghost value Gy3 is minimized or less than a set threshold. At this time, the longitudinal radius of curvature of the deformable reflective element 22 corresponding to the minimum value of Gy3 is R2 (the initial value of the longitudinal radius of curvature);

[0120] The collected ghost value Gy and the data corresponding to the longitudinal radius of curvature are stored in the HUD.

[0121] 3) Adjust the curvature radius of the mirror to compensate for ghosting

[0122] In the working of the HUD, the eyebox height parameter is read, and it is calculated that the eyebox position is between the highest position and the middle position or between the middle position and the lowest position. The longitudinal radius of curvature Rnow of the deformable mirror is calculated based on R0, R1 and R2 interpolation. The ghosting compensation is realized. That is, in the working process of the HUD, the eyebox height parameter is read, and it is determined that the eyebox position is between the highest position and the middle position, or between the middle position and the lowest position. According to the preset R0, R1 and R2 parameters, the current longitudinal radius of curvature Rnow of the deformable reflective element 22 is calculated by an interpolation algorithm to realize ghosting compensation.

[0123] Through the above steps, the optimization of ghosting can be realized regardless of the working position of the HUD.

[0124] In the embodiments of the present application, the first adjusting unit 31 and the second adjusting unit 41 are both actuators.

[0125] Exemplarily, the first adjusting unit 31 and the second adjusting unit 41 can be a piezoelectric actuator, an electromagnetic actuator, a shape memory alloy (SMA) actuator, an electrostatic actuator or a micro-electro-mechanical system (MEMS) actuator.

[0126] In the embodiment, the lateral curvature radius of the deformable reflecting element 22 ranges from 500 mm to 1200 mm.

[0127] In the embodiment, the deformable reflecting element 22 can be a mirror. If the thickness of the mirror is too thin, the mirror is easily deformed locally, which cannot guarantee the imaging quality and causes image distortion. If the thickness of the mirror is too thick, the actuator cannot drive the mirror to deform during the adjustment of the curvature. In a preferred example, the lateral curvature radius of the deformable reflecting element 22 ranges from 710 mm to 830 mm, which takes into account the imaging quality and the adjustment feasibility.

[0128] Exemplarily, the thickness of the mirror of the deformable reflecting element 22 can range from 1.5 mm to 5.0 mm.

[0129] In an optional embodiment, the dynamic adjustment range of the lateral curvature radius of the deformable mirror is set to 713.02 mm to 828.42 mm, and the adjustment step is ≤1 mm, so as to adapt to the fine control requirements of the HUD system on the virtual image distance and the imaging clarity.

[0130] Exemplarily, the dynamic adjustment range of the lateral curvature radius of the deformable mirror is set to 713.02 mm to 828.42 mm, the length of the deformable reflecting element 22 is 276 mm, and the edge position change amount of the deformable reflecting element 22 is ≤2.5 mm or ≤1% when the lateral curvature radius of the deformable reflecting element 22 is adjusted. For example, in an embodiment, the lateral curvature radius of the deformable reflecting element 22 is adjusted to 828.42 mm, and the imaging distance is 3.5 m. The lateral curvature radius of the deformable reflecting element 22 is adjusted to 713.02, and the imaging distance is 10 m.

[0131] In an optional embodiment, the length and width of the mirror are determined according to the imaging parameters, such as the virtual image size, distance, eyebox size and mirror position. After the size of the mirror is determined, the initial thickness of the deformable reflecting element 22 is calculated according to the deformation requirement and the thin plate theory. According to the specific shape and mounting mode of the deformable mirror, the parameters of the deformable mirror are adjusted in the finite element analysis software, so that the curvature of the mirror in the variable curvature process matches the theoretical design, and the imaging effect is effectively guaranteed. Finally, according to the curvature radius of the deformable mirror in the design simulation, the image distortion, imaging distance and ghosting are simulated in the imaging optical software to meet the requirements.

[0132] It should be noted that the thickness, curvature distribution and support structure of the mirror and other parameters can be dynamically optimized according to specific imaging quality requirements (such as MTF≥0.3@50lp / mm, distortion≤0.8%, stray light suppression≥90%).

[0133] In the embodiments of the present application, with reference to Figure 1 , the reflective optical assembly 2 further comprises: a fixed mirror 21 arranged between the image generation unit 1 and the deformable reflective element 22, for adjusting the initial propagation direction of the display light.

[0134] In this embodiment, the fixed mirror 21 folds the light emitted by the image generation unit 1 (such as an LCD or a DLP chip) to the deformable reflective element 22 (such as a dynamic curved mirror) through reflection, significantly shortening the longitudinal size of the HUD module (volume occupation can be reduced by 30%-50%), and adapting to the layout of compact vehicle instrument tables.

[0135] The embodiments of the present application also provide a display method of a head-up display system. The method is applied to the head-up display system as described above, as shown in Figure 3 , the method comprises the following steps:

[0136] S1: acquiring preset information;

[0137] S2: generating corresponding display image information according to the preset information;

[0138] S3: calculating a virtual display distance matched with the image information based on the image information;

[0139] S4: controlling the lateral curvature adjustment group 3 in the head-up display system to adjust the lateral curvature radius of the deformable reflective element 22 to a target value according to the virtual display distance;

[0140] S5: acquiring the longitudinal curvature radius of the deformable reflective element 22 in real time, and judging whether the longitudinal curvature radius is within a preset threshold;

[0141] If the longitudinal curvature radius is within the preset threshold, the head-up display system is controlled to project the display image information at the virtual display distance;

[0142] If the longitudinal curvature radius is not within the preset threshold, the longitudinal curvature correction group 4 is controlled to dynamically compensate the longitudinal curvature of the deformable reflective element 22 until the longitudinal curvature radius returns to the preset threshold;

[0143] S6: When the longitudinal curvature radius is at the preset threshold, control the head-up display system to project the display image information at the virtual display distance.

[0144] In step S1, the target parameters are obtained in real time by the vehicle-mounted sensor group (including but not limited to GPS positioning module, millimeter wave radar, visual camera, vehicle speed sensor).

[0145] The target parameters include:

[0146] Target intersection distance: calculated based on navigation system positioning data and preset path planning algorithm;

[0147] Vehicle dynamic information: including real-time vehicle speed, acceleration, relative distance and relative speed of the vehicle and the front vehicle;

[0148] Environmental perception information: such as road curvature, lane line identification, traffic signal light state, etc.

[0149] In one specific embodiment, the target intersection distance information is used to determine the projection parameters of the display image.

[0150] In step S2, based on the target intersection distance information, the corresponding display image content is generated.

[0151] The display image content includes:

[0152] Intersection guide icon: dynamically adjusting the arrow direction, size and color to match the spatial position of the target intersection.

[0153] Lane line rendering: generating a virtual-real combined lane line image according to the current lane of the vehicle and the navigation path, and determining its position and size in the display picture.

[0154] Depth information encoding: through image blocking or pixel-level depth mapping, the display content is labeled with virtual projection distance.

[0155] In step S3, according to the depth information encoding of the display image content, combined with the human eye visual characteristics and optical system parameters, the virtual projection distance of the display image is calculated.

[0156] In step S4, based on the calculated virtual display distance, the transverse curvature adjustment group 3 (such as piezoelectric ceramic driver) is controlled to dynamically adjust the transverse curvature radius of the deformable reflecting element 22, so that the focal plane of the display image matches the virtual projection distance.

[0157] During the adjustment process, the transverse curvature radius value is fed back in real time by the built-in curvature sensor.

[0158] In step S5, during the lateral curvature adjustment, the longitudinal curvature radius of the deformable reflective element 22 is monitored in real time by the longitudinal curvature sensor and compared with a preset threshold range.

[0159] If the longitudinal curvature radius is within the preset threshold: continue the lateral curvature adjustment until the display image is clearly projected to the virtual distance;

[0160] If the longitudinal curvature radius exceeds the preset threshold: start the longitudinal curvature correction group 4 (such as an electromagnetic actuator) to dynamically compensate the longitudinal curvature.

[0161] In step S6, when the longitudinal curvature radius returns to within the preset threshold, restart the lateral curvature adjustment group 3 to fine-tune the lateral curvature radius based on the updated reflective element state, ensuring that the projection distance and visual clarity of the display image meet the design requirements.

[0162] In an optional embodiment, the longitudinal curvature radius is determined according to the eyebox position.

[0163] The display method of the head-up display system provided by the embodiments of the present application can effectively reduce ghosting in the upper and lower eyeboxes. In the above-mentioned ghosting compensation method, corresponding ghosting values and longitudinal curvature radii of the deformable reflective element 22 are set for different eyebox positions: the ghosting value of the central eyebox is denoted as Gy1 (minimum value), and the corresponding longitudinal curvature radius of the deformable reflective element 22 is R0; the ghosting value of the upper eyebox is denoted as Gy2 (minimum value), and the corresponding longitudinal curvature radius of the deformable reflective element 22 is R1; the ghosting value of the lower eyebox is denoted as Gy3 (minimum value), and the corresponding longitudinal curvature radius of the deformable reflective element 22 is R2. When the eyebox position is between the highest position and the middle position, or between the middle position and the lowest position, the system will accurately calculate the current longitudinal curvature radius Rnow of the deformable reflective element 22 according to the preset R0, R1, and R2 parameters, and then realize precise ghosting compensation.

[0164] As can be seen, the optimal longitudinal curvature radius required by the deformable reflective element 22 differs when the eyebox position of the human eye is different. Based on this, the embodiments of the present application can determine the longitudinal curvature radius of the deformable reflective element 22 according to the eyebox position of the human eye, specifically, determine the initial value of the longitudinal curvature radius of the deformable reflective element 22 according to the eyebox position of the human eye, to ensure that optimal ghosting compensation effect can be achieved under various eyebox positions.

[0165] The focus of the above embodiments is the difference between the various embodiments. The different optimization features of the various embodiments can be combined to form a more optimal embodiment as long as they are not contradictory. Considering the brevity of the writing, further description is omitted here.

[0166] While certain embodiments of the application have been described herein in detail, those skilled in the art will appreciate that modifications can be made without departing from the scope and spirit of the application. The scope of the application is defined by the appended claims.

Claims

1. A heads-up display system, characterized by, The head-up display system comprises: an image generating unit (1) configured to generate and emit display light rays carrying image information; a reflective optical assembly (2) comprising at least one deformable reflective element (22), a reflective surface of the deformable reflective element (22) being configured to receive and reflect the display light rays; a lateral curvature adjusting group (3) disposed on a back reflective surface side of the deformable reflective element (22), the lateral curvature adjusting group (3) being arranged along a lateral direction of the deformable reflective element (22), and the lateral curvature adjusting group (3) being configured to apply stress to adjust a lateral curvature radius of the deformable reflective element (22) so that the head-up display system realizes continuous zooming; a longitudinal curvature correcting group (4) disposed on the back reflective surface side of the deformable reflective element (22), the longitudinal curvature correcting group (4) being arranged along a longitudinal direction of the deformable reflective element (22), and the longitudinal curvature correcting group (4) being configured to apply compensatory stress to correct a longitudinal curvature radius of the deformable reflective element (22) when the longitudinal curvature radius of the deformable reflective element (22) deviates from a preset threshold, so as to reduce an image ghosting value.

2. The head-up display system of claim 1, wherein, The reflective optical assembly (2) comprises one deformable reflective element (22), the lateral curvature adjusting group (3) is arranged along a lateral direction of the deformable reflective element (22), and the longitudinal curvature correcting group (4) is arranged along a longitudinal direction of the deformable reflective element (22).

3. The head-up display system of claim 1, wherein, The reflective optical assembly (2) comprises at least two deformable reflective elements (22), the lateral curvature adjusting group (3) is arranged along a lateral direction of one of the deformable reflective elements (22), and the longitudinal curvature correcting group (4) is arranged along a longitudinal direction of the other deformable reflective element (22).

4. The head-up display system of any one of claims 1-3, wherein, The lateral curvature adjusting group (3) comprises at least two first adjusting units (31), and the at least two first adjusting units (31) are arranged along a lateral center line of the deformable reflective element (22) at intervals.

5. The head-up display system of claim 4, wherein, The longitudinal curvature correcting group (4) comprises at least two second adjusting units (41), and the at least two second adjusting units (41) are arranged along a longitudinal center line of the deformable reflective element (22) at intervals.

6. The head-up display system of claim 5, wherein, The longitudinal curvature correcting group (4) comprises six second adjusting units (41), and the six second adjusting units (41) are divided into three groups of second adjusting units (41), and the arrangement of the three groups of second adjusting units (41) satisfies the following conditions: The first group of second adjusting units (41) are arranged along the longitudinal center line of the deformable reflective element (22) at intervals. The second group of second adjusting units (41) are symmetrically distributed on the longitudinal two sides of one of the first adjusting units (31). The third group of second adjusting units (41) are symmetrically distributed on the longitudinal two sides of the other first adjusting unit (31).

7. The head-up display system of claim 5, wherein, The first adjusting unit (31) and the second adjusting unit (41) are both actuators.

8. The head-up display system of claim 1, wherein, The head-up display system further comprises a storage unit configured to store a ghost value of the head-up display system displaying an image detected by an external device; In the case that the ghost value deviates from a preset threshold, a compensation stress is applied by the longitudinal curvature correction group (4) to correct the longitudinal curvature radius of the deformable reflective element (22), so as to adjust the ghost value of the head-up display system displaying an image.

9. The head-up display system of claim 1, wherein, The reflective optical assembly (2) further comprises a fixed mirror (21) arranged between the image generation unit (1) and the deformable reflective element (22) and configured to adjust the initial propagation direction of the display light.

10. A display method of a head-up display system, characterized by, The method is applied to the head-up display system according to any one of claims 1-9, and the method comprises the following steps: acquiring preset information; generating corresponding display image information according to the preset information; calculating a virtual display distance matched with the image information based on the image information; controlling a transverse curvature adjustment group (3) in the head-up display system to adjust the transverse curvature radius of the deformable reflective element (22) to a target value according to the virtual display distance; acquiring the longitudinal curvature radius of the deformable reflective element (22) in real time and determining whether the longitudinal curvature radius is within a preset threshold; if the longitudinal curvature radius is within the preset threshold, controlling the head-up display system to project the display image information at the virtual display distance; if the longitudinal curvature radius is not within the preset threshold, controlling the longitudinal curvature correction group (4) to dynamically compensate the longitudinal curvature of the deformable reflective element (22) until the longitudinal curvature radius returns to within the preset threshold; controlling the head-up display system to project the display image information at the virtual display distance when the longitudinal curvature radius is within the preset threshold.

11. The display method of the head-up display system according to claim 10, wherein The longitudinal curvature radius is determined according to the eyebox position. The longitudinal curvature radius is determined according to the eyebox position.

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