Optical waveguide hud angle adjustment system with dispersion compensation

Abstract

This invention discloses a waveguide HUD angle adjustment system with dispersion compensation, relating to the field of automotive head-up display technology. It includes an image generation unit, a wedge prism, a deflection prism, an arrayed waveguide, a compensation mirror, and a windshield. The image generation unit outputs an image beam carrying image information. The arrayed waveguide includes a waveguide substrate, an input reflection slope disposed within the waveguide substrate, and multiple output reflection slopes spaced apart along the light propagation direction. This invention fixes the exit angle adjustment function on the non-parallel input and output reflection slopes, and fixes the dispersion compensation function on a single wedge prism located in the front-stage optical path. This achieves a coordinated structure of front-stage dispersion compensation, waveguide-based exit angle adjustment, output pupil expansion protection, and rear-stage aberration compensation, realizing optical path regularization and low dispersion display without increasing the overall installation tilt angle.

Description

Technical Field

[0001] This invention relates to the field of automotive head-up display technology, specifically to an optical waveguide HUD angle adjustment system with dispersion compensation. Background Technology

[0002] The optical waveguide HUD angle adjustment system utilizes an image generation unit to generate image light carrying display information. This light is transmitted through a wedge prism, a deflection prism, and an array of optical waveguides, and then reflected by a compensation mirror and windshield to the driver's field of vision, forming an augmented reality virtual image in front of the driver. The arrayed optical waveguide structure is advantageous for miniaturization, achieving a larger virtual image distance, and expanding the pupil, making it suitable for automotive AR-HUD systems.

[0003] When existing automotive AR-HUDs are actually installed in vehicles, they usually need to deal with three mutually restrictive problems simultaneously: First, traditional reflective HUDs often require a long optical path and many optical components to obtain a large virtual image distance, resulting in a larger overall thickness and space occupation; Second, although arrayed waveguides can reduce the size, the output light angle of the conventional parallel input / output inclined structure is fixed. In order to match the curvature of the windshield and the requirements of the downward viewing angle, the whole unit still needs to be set with installation tilt angles in the X and Y directions, causing interference between the module and the dashboard space; Third, if the output angle is actively changed by designing the input and output reflective inclined surfaces to be non-parallel, it will introduce the separation of the output directions of different wavelengths of light, which manifests as color fringing and dispersion artifacts at the edge of the virtual image. Therefore, the technical problem actually faced by those skilled in the art is: how to eliminate the additional dual-axis tilt angle required for the system to adapt to the windshield while maintaining the advantages of miniaturization and pupil expansion capability of arrayed waveguide HUD, and at the same time suppress the chromatic dispersion caused by non-parallel inclined plane adjustment, so that the system has both regular structure, large virtual image distance and high display quality. Summary of the Invention

[0004] The purpose of this invention is to provide an optical waveguide HUD angle adjustment system with dispersion compensation to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an optical waveguide HUD angle adjustment system with dispersion compensation, comprising an image generation unit, a wedge prism, a deflection prism, an arrayed optical waveguide, a compensation mirror, and a windshield; The image generation unit is used to output an image beam carrying image information, and the principal ray corresponding to the center of the field of view in the image beam is defined as the central ray; the arrayed optical waveguide includes a waveguide substrate, a coupling reflection slope disposed inside the waveguide substrate, and multiple coupling reflection slopes spaced apart along the light propagation direction; a plane parallel to the lower surface of the waveguide substrate is defined as the reference propagation plane; The wedge prism is disposed between the image generation unit and the deflection prism, and is used to cause the central light ray to be deflected in a predetermined manner before entering the deflection prism, and to generate dispersion in the opposite direction to the dispersion direction introduced by the array optical waveguide; the deflection prism is used to deflect the central light ray emitted by the wedge prism by 90° and then guide it into the array optical waveguide, and to make the central light ray perpendicularly incident on the lower surface of the waveguide substrate. The arrayed waveguide is used to allow the central light beam to propagate inside the waveguide substrate after being reflected by the coupling reflection slope, and then be coupled out step by step by the multiple coupling reflection slopes at a preset exit angle to form an output beam after pupil dilation; the compensation mirror is disposed between the coupling area of ​​the arrayed waveguide and the windshield to compensate for the aberrations introduced by the windshield; the windshield is used to reflect the light emitted by the compensation mirror to the eye box area; the eye box area is the spatial area in which the image light reflected by the windshield can be received by the driver's eyes.

[0006] According to the above technical solution, the angle between the coupling-in reflection slope and the lower surface of the waveguide substrate is θ; the angle between each coupling-out reflection slope and the lower surface of the waveguide substrate is θ+α; where θ is the setting angle of the coupling-in reflection slope, and α is a non-zero adjustment amount; after the central ray is coupled out through each coupling-out reflection slope, the exit angle relative to the normal of the upper surface of the waveguide substrate is α.

[0007] According to the above technical solution, the multiple outgoing reflective slopes are an array of 3 to 15 parallel slopes; a high-reflectivity film is provided on the incoming reflective slopes to reflect the light entering the arrayed optical waveguide into the waveguide substrate; an angle-selective reflective film is provided on each outgoing reflective slope to reflect and couple out part of the light reaching the corresponding outgoing reflective slope, while the remaining light continues to propagate inside the waveguide substrate to form the pupil-enlarged eye box area.

[0008] According to the above technical solution, the plane parallel to the lower surface of the waveguide substrate is the reference propagation plane; the wedge prism includes a first working surface and a second working surface, the first working surface is parallel to the incident surface of the deflection prism, and the angle between the second working surface and the first working surface is β; the incident angle γ is the angle between the central ray and the normal of the first working surface; the exit angle φ is the angle between the central ray and the normal of the second working surface; the central ray is emitted from the second working surface and propagates parallel to the reference propagation plane, and enters the deflection prism.

[0009] According to the above technical solution, the refractive index of the material of the arrayed optical waveguide is n1; the refractive index of the material of the wedge prism is n2; n1 and n2 are equal; wherein, the dispersion introduced by the arrayed optical waveguide is the difference in the exit angle formed when different wavelengths of light in the visible light band are coupled out of the arrayed optical waveguide, and the dispersion introduced by the wedge prism is the difference in the exit angle formed when different wavelengths of light in the visible light band are emitted out of the wedge prism; by matching the magnitude and opposite direction of the exit angle difference introduced by the wedge prism and the exit angle difference introduced by the arrayed optical waveguide, the dispersion introduced by the non-parallelism of the coupling reflection slope and the coupling reflection slope is compensated.

[0010] According to the above technical solution, under the conditions that the first working surface is parallel to the incident surface of the turning prism, and the central ray is parallel to the reference propagation plane after exiting the second working surface, the exit angle φ satisfies φ=β; the incident angle γ satisfies: γ=arcsin{n2·sin[β-arcsinsinβ / n2]}; The above relationship is used to define the correspondence between the wedge angle β of the wedge prism, the refractive index n2 of the wedge prism material, and the incident angle γ of the central ray, so that the central ray propagates parallel to the reference propagation plane before entering the turning prism.

[0011] According to the above technical solution, the thickness of the waveguide substrate is no more than 2mm; the central ray propagates inside the waveguide substrate according to the laws of refraction and reflection, and is coupled out step by step by the multiple coupling reflection slopes under the condition of total internal reflection; the critical angle of total internal reflection is arcsin1 / n1.

[0012] According to the above technical solution, the image generation unit outputs collimated image light; the horizontal field of view of the collimated image light is denoted as FOVx, and the vertical field of view is denoted as FOVy; the distance of the virtual image formed by the system is denoted as VID, and the VID is not less than 10m; the working surface of the compensation mirror is a freeform surface.

[0013] The system's workflow is as follows: S1. Image generation stage: The image generation unit is powered on and starts up, outputting a collimated image beam carrying AR information such as navigation and ADAS warnings. The principal ray at the center of the field of view is the central ray, which serves as the reference for optical path calibration. S2, Dispersion pre-compensation stage: The image beam first enters the wedge prism 103. After the light of different wavelengths is refracted by the wedge prism, it produces a pre-deflection opposite to the dispersion direction of the array optical waveguide 101, thus completing the pre-compensation of dispersion. S3, Optical path reversal stage: The pre-compensated light beam enters the reversal prism 102. After the central light beam is reversed by 90°, it is perpendicularly incident on the lower surface of the waveguide substrate of the array optical waveguide 101, ensuring that the light beam enters the waveguide at a preset angle and satisfies the total internal reflection condition. S4. Coupled-in and total internal reflection propagation stage: After being reflected by the coupled-in reflection slope 1011, the perpendicularly incident light enters the waveguide substrate and propagates continuously in the waveguide at an angle greater than the critical angle of total internal reflection, without light leakage or loss of optical efficiency. S5, Angle Adjustment and Pupil Expansion Coupling Stage: The propagating light rays sequentially reach multiple coupling reflection slopes 1013. Each slope reflects part of the light rays out of the waveguide at a preset emission angle α, while the remaining light rays continue to propagate forward. Through the step-by-step coupling of multiple slopes, the active adjustment of the emission angle is achieved, which can match the windshield without tilting the entire machine. At the same time, one-dimensional pupil expansion is realized to form a large eye box area that adapts to the driver's eye movement range. S6, Aberration Correction Stage: The beam coupled out of the arrayed waveguide 101 enters the compensation mirror 104, and the freeform surface compensation mirror corrects optical aberrations such as distortion and astigmatism caused by the curved surface of the windshield glass to ensure image clarity. S7. Final Imaging Stage: The corrected beam of light is incident on the windshield 105, and after being reflected by the windshield, it enters the driver's eye box area. At a distance of more than 10m in front of the driver, an AR virtual image superimposed on the real road conditions is formed, completing the entire display process.

[0014] Compared with existing technologies, the beneficial effects achieved by this invention are as follows: Compared with conventional parallel inclined array waveguide solutions, this solution does not adapt to the windshield by adding housing attitude adjustment components, additional folding structures, or extra tilting installations. Instead, it directly utilizes the non-parallel relationship between the coupling-in reflection inclined surface and the coupling-out reflection inclined surface to generate the target emission angle, allowing the optical engine to be arranged in a more regular space and significantly reducing structural interference in the direction of the instrument panel. At the same time, this solution does not sacrifice the original pupil expansion capability of the array waveguide due to angle adjustment; the coupling-out reflection inclined surface still uses a multi-array structure to sequentially couple light rays.

[0015] Furthermore, this solution places a wedge prism between the image generation unit and the deflection prism, causing it to pre-disperde light of different wavelengths at an angle opposite to that of the arrayed waveguide. The angle is then adjusted by a subsequent non-parallel inclined waveguide, ultimately significantly reducing the overall chromatic aberration in front of the windshield. Combined with a compensating mirror to correct the windshield's own aberrations, the system can simultaneously achieve small size, regular layout, large virtual image distance, pupil-expanding output, and low color fringing, making it more suitable for automotive mass production scenarios. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the angle setting and basic optical path of the non-parallel inclined plane of the arrayed optical waveguide of the present invention; Figure 3 This is a schematic diagram of the dispersion-compensating wedge prism of the present invention; Figure 4 This is a schematic diagram of the core optical path principle of the optical waveguide HUD angle adjustment system of this invention; Figure 5 This is a schematic diagram illustrating the principle of total internal reflection propagation and progressive pupil expansion within an arrayed optical waveguide; Figure 6 This is a schematic diagram illustrating the principle of dispersion in existing non-parallel inclined array optical waveguides. Figure 7 This is a schematic diagram illustrating the dispersion compensation principle of the wedge prism of the present invention; Figure 8 This is a schematic diagram of the final imaging light propagation and virtual image formation of the system of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figures 1-8 The present invention provides a technical solution: a waveguide HUD angle adjustment system with dispersion compensation, comprising an image generation unit, a wedge prism 103, a turning prism 102, an arrayed waveguide 101, a compensation mirror 104, and a windshield 105; The image generation unit is used to output an image beam carrying image information. The principal ray in the image beam corresponding to the center of the field of view is defined as the central ray. The arrayed optical waveguide 101 includes a waveguide substrate, a coupling reflection slope 1011 disposed inside the waveguide substrate, and multiple coupling reflection slopes 1013 spaced apart along the light propagation direction. The plane parallel to the lower surface of the waveguide substrate is defined as the reference propagation plane. The wedge prism 103 is disposed between the image generation unit and the deflection prism 102 to cause the central light ray to be deflected in a predetermined manner before entering the deflection prism 102, and to generate dispersion in the opposite direction to the dispersion direction introduced by the array optical waveguide 101; the deflection prism 102 is used to deflect the central light ray emitted through the wedge prism 103 by 90° and then guide it into the array optical waveguide 101, and to make the central light ray perpendicularly incident on the lower surface of the waveguide substrate. The arrayed waveguide 101 is used to allow the central light beam to propagate inside the waveguide substrate after being reflected by the coupling reflection slope 1011, and then be coupled out step by step by multiple coupling reflection slopes 1013 at a preset exit angle to form an output beam after pupil dilation; the compensation mirror 104 is disposed between the coupling area of ​​the arrayed waveguide 101 and the windshield 105 to compensate for the aberrations introduced by the windshield 105; the windshield 105 is used to reflect the light emitted by the compensation mirror 104 to the eye box area; the eye box area is the spatial area in which the image light reflected by the windshield 105 can be received by the driver's eyes; The angle between the input reflection slope 1011 and the lower surface of the waveguide substrate is θ; the angle between each output reflection slope 1013 and the lower surface of the waveguide substrate is θ+α; where θ is the setting angle of the input reflection slope 1011, and α is a non-zero adjustment amount; after the central ray is coupled out through each output reflection slope 1013, the exit angle relative to the normal of the upper surface of the waveguide substrate is α. The multiple output reflection slopes 1013 consist of an array of 3 to 15 parallel slopes; a high-reflectivity film is provided on the input reflection slopes 1011 to reflect the light entering the array optical waveguide 101 into the waveguide substrate; an angle-selective reflection film is provided on each output reflection slope 1013 to reflect and couple out part of the light reaching the corresponding output reflection slope 1013, while the remaining light continues to propagate inside the waveguide substrate to form the pupil-enlarged eye box region; A plane parallel to the lower surface of the waveguide substrate is the reference propagation plane; the wedge prism 103 includes a first working surface 1031 and a second working surface 1032. The first working surface 1031 is parallel to the incident surface of the deflection prism 102, and the angle between the second working surface 1032 and the first working surface 1031 is β; the incident angle γ is the angle between the central ray and the normal of the first working surface 1031; the exit angle φ is the angle between the central ray and the normal of the second working surface 1032; the central ray propagates parallel to the reference propagation plane after exiting the second working surface 1032 and enters the deflection prism 102; The refractive index of the material of the arrayed waveguide 101 is n1; the refractive index of the material of the wedge prism 103 is n2; n1 and n2 are equal; wherein, the dispersion introduced by the arrayed waveguide 101 is the difference in the exit angle formed when different wavelengths of light in the visible light band are coupled out of the arrayed waveguide 101, and the dispersion introduced by the wedge prism 103 is the difference in the exit angle formed when different wavelengths of light in the visible light band are emitted out of the wedge prism 103; by matching the magnitude and opposite direction of the exit angle difference introduced by the wedge prism 103 and the exit angle difference introduced by the arrayed waveguide 101, the dispersion introduced by the non-parallelism of the coupling reflection slope 1011 and the coupling reflection slope 1013 is compensated; Under the condition that the first working surface 1031 is parallel to the incident surface of the deflection prism 102, and the central ray is parallel to the reference propagation plane after exiting the second working surface 1032, the exit angle φ satisfies φ=β; the incident angle γ satisfies: γ=arcsin{n2·sin[β-arcsinsinβ / n2]}; The above relationship is used to define the correspondence between the wedge angle β of the wedge prism 103, the refractive index n2 of the material of the wedge prism 103, and the incident angle γ of the central ray, so that the central ray propagates parallel to the reference propagation plane before entering the turning prism 102. The thickness of the waveguide substrate is no more than 2 mm; the central ray propagates inside the waveguide substrate according to the laws of refraction and reflection, and under total internal reflection conditions, it is coupled out step by step by multiple coupling reflective inclined planes 1013; the critical angle of total internal reflection is arcsin1 / n1; The image generation unit outputs collimated image light; the horizontal field of view of the collimated image light is denoted as FOVx, and the vertical field of view is denoted as FOVy; the distance of the virtual image formed by the system is denoted as VID, and VID is not less than 10m; the working surface of the compensation mirror 104 is a freeform surface.

[0019] Working principle: Figure 1 The system's entire component layout and complete optical path are fully demonstrated, showing the spatial relationships between the image generation unit, wedge prism 103, deflection prism 102, arrayed waveguide 101, compensation mirror 104, windshield 105, and eye box region in the order of light propagation. The collaborative architecture of pre-stage dispersion compensation, waveguide-based output angle adjustment, coupling-side pupil dilation protection, and post-stage aberration compensation presents the entire process from image light generation to the final AR virtual image entering the driver's eyes.

[0020] Figure 2The focus is on showcasing the core angle adjustment structure of the arrayed waveguide 101, presenting the angle θ between the coupling-in reflection ramp 1011 and the lower surface of the waveguide substrate, and the angle θ+α between the coupling-out reflection ramp 1013 and the lower surface of the waveguide substrate. This clarifies the non-parallel angular relationship between the two and the design logic of the α angle adjustment. By setting the coupling-in and coupling-out reflection ramps as non-parallel structures, the exit direction of light after reflection by the coupling-out reflection ramp 1013 can be directly changed, allowing the central light to exit at a preset α angle. This matches the curvature and downward viewing angle requirements of the windshield without adjusting the overall installation posture. Eliminating the installation tilt angle in the X and Y directions of the entire device from the source of the optical structure restores the structural regularity and miniaturization advantages of the arrayed waveguide.

[0021] Figure 3 The core structure of the wedge prism 103 is displayed, clearly showing its first working surface 1031, second working surface 1032, and the wedge angle β between the two working surfaces, clarifying the spatial relationship of the working surfaces and the definition of core parameters. Its principle utilizes the refractive properties of the wedge prism. When light is incident on two non-parallel working surfaces at a specific incident angle, visible light of different wavelengths will be deflected differently due to the difference in refractive index, thus forming controllable angular dispersion.

[0022] Figure 4 The propagation process of the system's core optical path is presented, sequentially showing the entire process of the central ray emitted from the image generation unit, through pre-compensation by the wedge prism 103, deflection by the turning prism 102, total internal reflection within the array waveguide 101, and angle-adjusted coupling. The θ angle of the coupling-in reflection slope 1011, the θ+α angle of the coupling-out reflection slope 1013, and the relationship between the incident and exit angles of the wedge prism 103 are also marked. The ray first undergoes dispersion pre-compensation in the opposite direction to that of the array waveguide 101 via the pre-wedge prism 103, then is perpendicularly guided into the array waveguide 101 via the turning prism 102. While the exit angle is adjusted through the non-parallel slope, the dispersion introduced by the waveguide cancels out the dispersion from the pre-compensation.

[0023] Figure 5 The demonstration showcases the logic behind light propagation and pupil expansion within the arrayed waveguide 101, presenting an arrayed arrangement of multiple coupling-out reflective ramps 1013, and the complete process of total internal reflection propagation and step-by-step coupling of light within the waveguide substrate. Light rays reflected into the waveguide substrate by the coupling-in reflective ramps 1011 satisfy the critical angle condition for total internal reflection and propagate along the waveguide. Upon reaching each coupling-out reflective ramp 1013, a portion of the light is reflected and coupled out of the waveguide, while the remaining light continues to propagate forward. Through the step-by-step coupling of 3-15 parallel array ramps, one-dimensional pupil expansion is achieved, forming an eye box region adapted to the driver's eye movement range.

[0024] Figure 6This study demonstrates that when only non-parallel inclined planes are used for angle adjustment and no dispersion compensation structure is implemented, light rays of different wavelengths exhibit angular dispersion after being coupled out of the arrayed waveguide, resulting in separation of their exit directions. The principle is as follows: Different wavelengths of light within the visible light band have different refractive indices in the optical medium. When the input and output reflective inclined planes of the arrayed waveguide are non-parallel, the difference in deflection between different wavelengths is amplified, ultimately manifesting as inconsistent exit angles of the coupled light rays and color artifacts appearing at the edges of the virtual image.

[0025] Figure 7 The paper presents the deflection effect of the wedge prism 103 on light of different wavelengths, and the matching and cancellation logic of its dispersion with the arrayed waveguide 101. The principle is as follows: by matching the refractive indices of the materials of the arrayed waveguide 101 and the wedge prism 103 (preferably n1=n2), and precisely designing the wedge angle β of the wedge prism and the incident angle γ of the light, the dispersion generated by the wedge prism 103 is matched in magnitude and opposite in direction to the dispersion introduced by the non-parallel inclined surface of the arrayed waveguide 101, ultimately achieving dispersion cancellation throughout the optical path and eliminating virtual image fringe artifacts.

[0026] Figure 8 The imaging optical path at the back end of the system is demonstrated, showing the complete process of light rays coupled out of the arrayed waveguide 101, corrected by the compensating mirror 104, reflected by the windshield 105, entering the eyebox area, and forming a long-distance AR virtual image. The light rays carrying image information coupled out of the arrayed waveguide are first corrected by the freeform surface compensating mirror 104 to correct the optical aberrations caused by the curvature of the windshield, and then reflected by the windshield to the eyebox area within the driver's eye movement range, forming a long-distance AR virtual image with a VID ≥ 10m in front of the driver, realizing the superposition and display of virtual information and real road conditions.

[0027] Example 1: The specific implementation parameters of this example are as follows: the array waveguide 101 and the wedge prism 103 are made of the same optical material with a refractive index n1=n2=1.5168. The thickness of the waveguide substrate of the array waveguide is 1.8mm. The angle θ between the coupling reflection slope 1011 and the lower surface of the waveguide substrate is 25°, and the adjustment angle α=10°. The corresponding angle between the coupling reflection slope 1013 and the lower surface of the waveguide substrate is 35°. The wedge angle β of the wedge prism 103 is 10°, and the incident angle γ of the central ray incident on the first working surface 1031 of the wedge prism is 5.2°. The image generation unit adopts a MicroOLED microdisplay chip, and the field of view of the collimated image light output is 10°×4°. The final virtual image distance VID formed by the system is 15m. Simulation results show that the proposed solution can completely eliminate the dispersion introduced by the non-parallel inclined plane, while eliminating the need for an installation tilt angle, thus achieving a standardized layout and excellent AR display effect.

[0028] The workflow of this invention is as follows: S1. Image generation stage: The image generation unit is powered on and starts up, outputting a collimated image beam carrying AR information such as navigation and ADAS warnings. The principal ray at the center of the field of view is the central ray, which serves as the reference for optical path calibration. S2, Dispersion pre-compensation stage: The image beam first enters the wedge prism 103. After the light of different wavelengths is refracted by the wedge prism, it produces a pre-deflection opposite to the dispersion direction of the array optical waveguide 101, thus completing the pre-compensation of dispersion. S3, Optical path reversal stage: The pre-compensated light beam enters the reversal prism 102. After the central light beam is reversed by 90°, it is perpendicularly incident on the lower surface of the waveguide substrate of the array optical waveguide 101, ensuring that the light beam enters the waveguide at a preset angle and satisfies the total internal reflection condition. S4. Coupled-in and total internal reflection propagation stage: After being reflected by the coupled-in reflection slope 1011, the perpendicularly incident light enters the waveguide substrate and propagates continuously in the waveguide at an angle greater than the critical angle of total internal reflection, without light leakage or loss of optical efficiency. S5, Angle Adjustment and Pupil Expansion Coupling Stage: The propagating light rays sequentially reach multiple coupling reflection slopes 1013. Each slope reflects part of the light rays out of the waveguide at a preset emission angle α, while the remaining light rays continue to propagate forward. Through the step-by-step coupling of multiple slopes, the active adjustment of the emission angle is achieved, which can match the windshield without tilting the entire machine. At the same time, one-dimensional pupil expansion is realized to form a large eye box area that adapts to the driver's eye movement range. S6, Aberration Correction Stage: The beam coupled out of the arrayed waveguide 101 enters the compensation mirror 104, and the freeform surface compensation mirror corrects optical aberrations such as distortion and astigmatism caused by the curved surface of the windshield glass to ensure image clarity. S7. Final Imaging Stage: The corrected beam of light is incident on the windshield 105, and after being reflected by the windshield, it enters the driver's eye box area. At a distance of more than 10m in front of the driver, an AR virtual image superimposed on the real road conditions is formed, completing the entire display process.

[0029] This solution achieves long-distance virtual image imaging of over 10 meters. When drivers observe AR navigation information, their eyes do not need to frequently refocus between the nearby dashboard and distant road conditions, effectively reducing driving fatigue. At the same time, the virtual information is completely superimposed on the real road conditions without visual gaps, which can significantly reduce the risk of information misjudgment in autonomous driving scenarios. The extremely miniaturized overall structure breaks the industry status quo that AR-HUDs can only be adapted to mid-to-high-end vehicles, and can be applied to compact vehicles and entry-level new energy vehicles, promoting the popularization of AR-HUDs across all vehicle types. This solution adopts a geometric optical architecture, eliminating the need for high-end processes such as holographic grating exposure and nanoimprinting of diffractive waveguides. All optical components use mature mass production processes for automobiles. Compared with AR-HUDs with the same performance of diffractive waveguides, the mass production cost can be reduced by more than 30%, giving it a strong advantage in industrial application.

[0030] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0031] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A waveguide HUD angle adjustment system with dispersion compensation, characterized in that: Includes an image generation unit, a wedge prism, a deflection prism, an array of optical waveguides, a compensation mirror, and a windshield; The image generation unit is used to output an image beam carrying image information, and the principal ray corresponding to the center of the field of view in the image beam is defined as the central ray; the arrayed optical waveguide includes a waveguide substrate, a coupling reflection slope disposed inside the waveguide substrate, and multiple coupling reflection slopes spaced apart along the light propagation direction; a plane parallel to the lower surface of the waveguide substrate is defined as the reference propagation plane; The wedge prism is disposed between the image generation unit and the deflection prism, and is used to cause the central light ray to be deflected in a predetermined manner before entering the deflection prism, and to generate dispersion in the opposite direction to the dispersion direction introduced by the array optical waveguide; the deflection prism is used to deflect the central light ray emitted by the wedge prism by 90° and then guide it into the array optical waveguide, and to make the central light ray perpendicularly incident on the lower surface of the waveguide substrate. The arrayed waveguide is used to allow the central light beam to propagate inside the waveguide substrate after being reflected by the coupling reflection slope, and to be coupled out step by step by the multiple coupling reflection slopes at a preset exit angle to form an output beam after pupil expansion; the compensation mirror is disposed between the coupling area of ​​the arrayed waveguide and the windshield glass to compensate for the aberrations introduced by the windshield glass. The windshield is used to reflect light emitted through the compensating lens to the eye box area; The eye box area is the spatial area in which the image light reflected by the windshield can be received by the driver's eyes.

2. The optical waveguide HUD angle adjustment system with dispersion compensation according to claim 1, characterized in that: The angle between the input reflection slope and the lower surface of the waveguide substrate is θ; the angle between each output reflection slope and the lower surface of the waveguide substrate is θ+α; where θ is the setting angle of the input reflection slope and α is a non-zero adjustment amount; the exit angle of the central ray relative to the normal of the upper surface of the waveguide substrate after being coupled out by each output reflection slope is α.

3. The optical waveguide HUD angle adjustment system with dispersion compensation according to claim 2, characterized in that: The multiple outgoing reflective slopes are arrayed in groups of 3 to 15, which are parallel to each other. A high-reflectivity film is provided on the incoming reflective slopes to reflect the light entering the arrayed waveguide into the waveguide substrate. An angle-selective reflective film is provided on each outgoing reflective slope to reflect and couple out a portion of the light reaching the corresponding outgoing reflective slope, while the remaining light continues to propagate inside the waveguide substrate to form the pupil-enlarged eye box region.

4. The optical waveguide HUD angle adjustment system with dispersion compensation according to claim 3, characterized in that: A plane parallel to the lower surface of the waveguide substrate is the reference propagation plane; the wedge prism includes a first working surface and a second working surface, the first working surface is parallel to the incident surface of the deflection prism, and the angle between the second working surface and the first working surface is β; the incident angle γ is the angle between the central ray and the normal of the first working surface; the exit angle φ is the angle between the central ray and the normal of the second working surface; the central ray propagates parallel to the reference propagation plane after exiting the second working surface and enters the deflection prism.

5. The optical waveguide HUD angle adjustment system with dispersion compensation according to claim 4, characterized in that: The refractive index of the material of the arrayed optical waveguide is n1; the refractive index of the material of the wedge prism is n2; n1 and n2 are equal; wherein, the dispersion introduced by the arrayed optical waveguide is the difference in the exit angle formed when different wavelengths of light in the visible light band are coupled out of the arrayed optical waveguide, and the dispersion introduced by the wedge prism is the difference in the exit angle formed when different wavelengths of light in the visible light band are emitted out of the wedge prism; by matching the magnitude and opposite direction of the exit angle difference introduced by the wedge prism and the exit angle difference introduced by the arrayed optical waveguide, the dispersion introduced by the non-parallelism of the coupling reflection slope and the coupling reflection slope is compensated.

6. The optical waveguide HUD angle adjustment system with dispersion compensation according to claim 5, characterized in that: Under the condition that the first working surface is parallel to the incident surface of the turning prism, and the central ray is parallel to the reference propagation plane after exiting the second working surface, the exit angle φ satisfies φ=β; the incident angle γ satisfies: γ=arcsin{n2·sin[β-arcsinsinβ / n2]}; The above relationship is used to define the correspondence between the wedge angle β of the wedge prism, the refractive index n2 of the wedge prism material, and the incident angle γ of the central ray, so that the central ray propagates parallel to the reference propagation plane before entering the turning prism.

7. The optical waveguide HUD angle adjustment system with dispersion compensation according to claim 6, characterized in that: The thickness of the waveguide substrate is no greater than 2 mm; the central ray propagates inside the waveguide substrate according to the laws of refraction and reflection, and is coupled out step by step by the multiple coupling reflective slopes under total internal reflection conditions; the critical angle of total internal reflection is arcsin1 / n1.

8. The optical waveguide HUD angle adjustment system with dispersion compensation according to claim 7, characterized in that: The image generation unit outputs collimated image light; the horizontal field of view of the collimated image light is denoted as FOVx, and the vertical field of view is denoted as FOVy; the distance of the virtual image formed by the system is denoted as VID, and the VID is not less than 10m; the working surface of the compensation mirror is a freeform surface.

9. The optical waveguide HUD angle adjustment system with dispersion compensation according to claim 6, characterized in that: The workflow of this system is as follows: S1. Image generation stage: The image generation unit is powered on and starts up, outputting a collimated image beam carrying AR information such as navigation and ADAS warnings. The principal ray at the center of the field of view is the central ray, which serves as the reference for optical path calibration. S2, Dispersion pre-compensation stage: The image beam first enters the wedge prism 103. After the light of different wavelengths is refracted by the wedge prism, it produces a pre-deflection opposite to the dispersion direction of the array optical waveguide 101, thus completing the pre-compensation of dispersion. S3, Optical path reversal stage: The pre-compensated light beam enters the reversal prism 102. After the central light beam is reversed by 90°, it is perpendicularly incident on the lower surface of the waveguide substrate of the array optical waveguide 101, ensuring that the light beam enters the waveguide at a preset angle and satisfies the total internal reflection condition. S4. Coupled-in and total internal reflection propagation stage: After being reflected by the coupled-in reflection slope 1011, the perpendicularly incident light enters the waveguide substrate and propagates continuously in the waveguide at an angle greater than the critical angle of total internal reflection, without light leakage or loss of optical efficiency. S5, Angle Adjustment and Pupil Expansion Coupling Stage: The propagating light rays sequentially reach multiple coupling reflection slopes 1013. Each slope reflects part of the light rays out of the waveguide at a preset emission angle α, while the remaining light rays continue to propagate forward. Through the step-by-step coupling of multiple slopes, the active adjustment of the emission angle is achieved, which can match the windshield without tilting the entire machine. At the same time, one-dimensional pupil expansion is realized to form a large eye box area that adapts to the driver's eye movement range. S6, Aberration Correction Stage: The beam coupled out of the arrayed waveguide 101 enters the compensation mirror 104, and the freeform surface compensation mirror corrects optical aberrations such as distortion and astigmatism caused by the curved surface of the windshield glass to ensure image clarity. S7. Final Imaging Stage: The corrected beam of light is incident on the windshield 105, and after being reflected by the windshield, it enters the driver's eye box area. At a distance of more than 10m in front of the driver, an AR virtual image superimposed on the real road conditions is formed, completing the entire display process.

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