Image generation unit and head-up display

Abstract

The invention relates to an image generation unit and a head-up display. The image generation unit comprises a first projection module used for emitting first image light, a second projection module used for emitting second image light and a diffusion screen. Wherein the first image light enters the first area of the diffusion screen, the second image light enters the second area of the diffusion screen, and the first area and the second area partially or completely coincide to form a display image source; the display image source is used for projecting to the projection medium after passing through the optical adjusting lens group so as to form virtual images in a horizontal view field and a vertical view field; for any point on the diffusion screen, the incident angles of the first image light and the second image light entering the diffusion screen do not coincide. According to the image generation unit and the head-up display, the stereoscopic virtual image can be displayed, and the virtual-real fusion effect of the virtual image and the road real scene is optimized.

Description

Technical Field

[0001] The present disclosure relates to the technical field of head-up display, and in particular to an image generation unit and a head-up display. Background Art

[0002] Head Up Display (HUD), also known as Head-Up Display, is now widely used in automobiles. The basic principle of the vehicle head-up display is to project important driving information such as vehicle condition and navigation onto a projection medium such as a windshield or a special screen inside the car through a designed optical path to assist driving.

[0003] The head-up display of the prior art has the problems that the virtual image has a weak three-dimensional sense and the virtual image and the real road scene have a poor fusion effect.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] The purpose of the present disclosure is to provide an image generation unit and a head-up display, which can display a virtual image with a three-dimensional sense and optimize the virtual-reality fusion effect of the virtual image and the real road scene.

[0006] According to one aspect of the present disclosure, there is provided an image generating unit, comprising a first projection module for emitting a first image light, a second projection module for emitting a second image light, and a diffusion screen;

[0007] Among them, the first image light is incident on the first area of ​​the diffusion screen, and the second image light is incident on the second area of ​​the diffusion screen, and the first area and the second area are partially or completely overlapped to form a display image source; the display image source is used to be projected onto the projection medium after passing through the optical adjustment lens group to form a virtual image in the horizontal field of view and the vertical field of view; for any point on the diffusion screen, the incident angles of the first image light and the second image light entering the diffusion screen do not overlap.

[0008] In an exemplary embodiment of the present disclosure, the angle between the principal ray of the first image light and the principal ray of the second image light in the horizontal field of view is A, wherein A=2*atan(d / 2 / L0), d is the designed binocular distance, and L0 is the distance between the display image source and the optical principal surface of the optical adjustment lens group.

[0009] In an exemplary embodiment of the present disclosure, a scattering angle of the first image light by the diffuser screen within the horizontal field of view is no greater than A; and a scattering angle of the second image light by the diffuser screen within the horizontal field of view is no greater than A.

[0010] In an exemplary embodiment of the present disclosure, the included angle A between the chief ray of the first image light ray and the chief ray of the second image light ray in the horizontal field of view is not greater than 18.5° and not less than 6°.

[0011] In an exemplary embodiment of the present disclosure, the scattering angle B of the diffuser screen for the first image light ray in the vertical field of view is not less than 2*atan(t / 2 / L0), where t is the designed width of the eye box in the vertical direction and L0 is the distance from the display image source to the optical principal plane of the optical adjustment lens group.

[0012] In an exemplary embodiment of the present disclosure, the scattering angle of the diffuser screen for the first image light ray in the vertical field of view is not less than 4°, and the scattering angle of the diffuser screen for the second image light ray in the vertical field of view is not less than 4°.

[0013] In an exemplary embodiment of the present disclosure, the diffuser screen is a transmissive diffuser screen, and the diffuser screen is used to scatter the first image light ray transmitted through the diffuser screen from the first region; the diffuser screen is used to scatter the second image light ray transmitted through the diffuser screen from the second region;

[0014] Wherein, for any point on the diffuser screen, the angles at which the first image light ray and the second image light ray are transmitted through the diffuser screen are not coincident.

[0015] In an exemplary embodiment of the present disclosure, the image generation unit further includes a synthesis unit, and the synthesis unit is used to transmit the first image light ray so that the first image light ray is incident on the first region of the diffuser screen through the synthesis unit; the synthesis unit is further used to reflect the second image light ray so that the second image light ray is incident on the second region of the diffuser screen.

[0016] In an exemplary embodiment of the present disclosure, the synthesis unit includes a partially reflective device, a part of the first image light ray is transmitted through the partially reflective device and incident on the diffuser screen, and a part of the first image light ray is reflected by the partially reflective device and cannot be incident on the diffuser screen;

[0017] A part of the second image light ray is reflected by the partially reflective device and incident on the diffuser screen, and a part of the second image light ray is transmitted through the partially reflective device and cannot be incident on the diffuser screen.

[0018] In an exemplary embodiment of the present disclosure, the first image light ray includes a light ray with a first polarization state, and the second image light ray includes a light ray with a second polarization state; the synthesis unit includes a polarization reflection device, and the polarization reflection device is used to transmit the light ray with the first polarization state, and the polarization reflection device is used to reflect the light ray with the second polarization state.

[0019] In an exemplary embodiment of the present disclosure, the second image light ray emitted by the second projection module is formed after pre-distortion processing by a distortion correction matrix C1 with reference to the first image light ray emitted by the first projection module;

[0020] Alternatively, the first image light rays emitted by the first projection module are formed after pre-distortion processing by the distortion correction matrix C2 with reference to the second image light rays emitted by the second projection module.

[0021] According to another aspect of the present disclosure, a head-up display is provided, including the image generation unit and the optical adjustment lens group according to any one of the above, the image generation unit is used to generate a display image source; the optical adjustment lens group is used to project the display image source onto a projection medium to form virtual images within a horizontal field of view and a vertical field of view;

[0022] Wherein, for any point on the image plane of the virtual image, the exit angles of the first virtual image light ray corresponding to the first image light ray and the second virtual image light ray corresponding to the second image light ray do not coincide.

[0023] For the image generation unit and the head-up display of the present disclosure, since the monocular images are independently projected by the first projection module or the second projection module, there will be no loss of resolution. The incident angles of the first image light ray and the second image light ray on the diffuser screen do not coincide, so the first image light ray and the second image light ray can enter the driver's left eye and right eye (or right eye and left eye) respectively, enabling the driver's left eye and right eye to see different images. According to the binocular vision fusion effect, three-dimensional stereoscopic display is achieved. In addition, for the first virtual image and the second virtual image at different positions on the image plane, their positions in the line-of-sight directions of the left eye and the right eye are different, so the virtual image distances observed by the human eye are also different. Therefore, the image generation unit of the present disclosure can also form stereoscopic images at different distances, which is beneficial to improving the fusion degree of the virtual image projected by the head-up display and the real scene, performing augmented reality, and enhancing the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0025] To better understand the present disclosure, reference may be made to the embodiments shown in the following drawings. The components in the drawings are not necessarily to scale, and related elements may be omitted to emphasize and clearly illustrate the technical features of the present disclosure. Additionally, related elements or components may have different arrangements as known in the art. Furthermore, in the drawings, the same reference numerals denote the same or similar components in each drawing. Among them:

[0026] Figure 1 It is a schematic diagram of the imaging principle of the image generation unit of the present disclosure;

[0027] Figure 2 Schematic diagram of the principle for the image generation unit of the present disclosure to form stereoscopic vision;

[0028] Figure 3 Schematic diagram of the image generation unit of the present disclosure to form stereoscopic images at different distances;

[0029] Figure 4 Schematic diagram of the optical paths of the first image light ray and the second image light ray after exiting from the diffusing screen in an exemplary embodiment of the image generation unit of the present disclosure;

[0030] Figure 5 Schematic diagram of the scattering angles and scattering regions of the diffusing screen for the first image light ray and the second image light ray in the horizontal field of view direction of the image generation unit of the present disclosure;

[0031] Figure 6 Schematic diagram of an exemplary embodiment of the image generation unit of the present disclosure;

[0032] Figure 7 Schematic diagram of the synthesis unit in an exemplary embodiment of the image generation unit of the present disclosure;

[0033] Figure 8 Schematic diagram of the synthesis unit in an exemplary embodiment of the image generation unit of the present disclosure;

[0034] Figure 9 Schematic diagram of the optical path of the second image light ray in an exemplary embodiment of the image generation unit of the present disclosure;

[0035] Figure 10 Schematic diagram of the overall optical paths of the first image light ray and the second image light ray in an exemplary embodiment of the image generation unit of the present disclosure;

[0036] Figure 11 Schematic diagram of an exemplary embodiment of the head-up display of the present disclosure.

[0037] Explanation of the reference numerals is as follows:

[0038] 1. First projection module; 2. Second projection module; 3. Synthesis unit; 31. Partial reflection device; 32. Polarization reflection device; 4. Diffusing screen; 5. Windshield; 6. Image plane; 61. First virtual image; 62. Second virtual image; 611. First icon; 612. Second icon; 621. Third icon; 622. Fourth icon; 71. Left eye; 72. Right eye; 81. Stereoscopic image; 811. First stereoscopic image; 812. Second stereoscopic image; 91. First reflector; 92. Second reflector. Detailed implementation manners

[0039] The technical solutions in the exemplary embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the exemplary embodiments of the present disclosure. The exemplary embodiments described herein are for illustrative purposes only and are not intended to limit the protection scope of the present disclosure. Therefore, it should be understood that various modifications and changes can be made to the exemplary embodiments without departing from the protection scope of the present disclosure.

[0040] Unless otherwise specified or stated, the technical terms or scientific terms used in the present disclosure should have the ordinary meanings understood by those of ordinary skill in the art to which the present disclosure pertains. The present disclosure uses "first", "second", etc. only as labels and does not limit the quantity, importance, or order of their objects. Words such as "including" or "comprising" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0041] Further, it should be understood that when it is described in the exemplary embodiments of the present disclosure that an optical surface is "concave" or "convex", it is relative to the direction of the light incident on the surface. For example, if an optical surface is "concave", the distance from a point on the incident light ray to the center of the surface on the optical axis is greater than the distance from the point to the periphery of the surface.

[0042] The field of view is the range of the outline of the object observed by the human eye. In the description of the present disclosure, for a head-up display, the horizontal field of view can also be understood as the lateral field of view, that is, the maximum visible range of the virtual image observed by the observer in the lateral direction; the vertical field of view can also be understood as the longitudinal or vertical field of view, that is, the maximum visible range of the virtual image observed by the observer in the longitudinal or vertical direction. For example, for a vehicle-mounted head-up display, based on the vehicle coordinate system, the horizontal field of view direction is the horizontal direction of the vehicle coordinate system, and the vertical field of view direction is the vertical direction of the vehicle coordinate system.

[0043] The eye box is the area where the binoculars of the driver or observer are located. In the design of a head-up display, the eye box range can be determined according to the height, posture, etc. of the driver. The eye box defines an effective area for an eye point. When the eye point position of the observer moves within this effective area, the observer can see a virtual image that meets the requirements. Areas outside the eye box may present problems such as image distortion, incomplete color display, or even non-display.

[0044] To facilitate the description of the solutions of the present disclosure, a possible application scenario provided by the present disclosure takes a head-up display applied to an automobile as an example. The driver is the observer, and the windshield of the automobile is the projection medium that reflects image light to the human eye. Those skilled in the art should understand that the head-up display can also be applied to other fields such as ships and the aviation field, or other display device fields such as head-mounted display devices. The projection medium can also be other lenses or screens that can achieve reflection, and the observer can be someone else. The image generation unit and the head-up display of the exemplary embodiments of the present disclosure are not limited by the actual application scenario of the head-up display.

[0045] In the field of head-up displays, there is a need to project virtual images with a three-dimensional effect. One three-dimensional display solution in the related art is to project two virtual images with unequal imaging distances. By magnifying and reducing the virtual image UI, a "quasi-three-dimensional" effect in a two-dimensional plane is achieved. However, this solution has poor authenticity and a bad experience. Another three-dimensional display solution is to attach a lenticular grating to the light-emitting side of the display screen that generates and emits imaging light in the head-up display. The lenticular lens is used to refract the imaging light emitted by the display screen, so that the imaging light enters different regions of the eye box from different directions on the light-emitting surface of the lenticular grating, and enters the left and right eyes of the driver respectively, forming a binocular aberration, and thus generating a stereoscopic vision. In this solution, the left and right eyes each use different pixels of the display screen, and the pixels cannot overlap. The number of display pixels observed by the driver is half of the actual display screen pixels, resulting in a loss of resolution.

[0046] To address the above problems, the present disclosure provides an image generation unit and a head-up display that can display virtual images with a three-dimensional sense and optimize the virtual-real fusion effect between the virtual images and the road scene.

[0047] The image generation unit of the present disclosure can be used in a head-up display. To facilitate the description of the solutions of the present disclosure, a possible head-up display in an exemplary embodiment of the present disclosure is briefly described first. It should be noted that these explanations are for the convenience of those skilled in the art to understand and do not constitute a limitation on the protection scope required by this application.

[0048] A head-up display generally includes an image generation unit and an optical adjustment lens group. The image generation unit is used to generate image light corresponding to virtual images. The optical adjustment lens group can include one or more reflecting mirrors, or can also include optical devices such as optical waveguides. The optical adjustment lens group is used to turn the image light to a projection medium outside the head-up display. For example, the image light can be reflected onto a special screen in front of the driver, or directly reflected to an appropriate position on the windshield of the automobile. The light after the reflection of the image light by the windshield enters the eye box range and the virtual image corresponding to the image light is observed by the driver's binocular vision.

[0049] According to a first aspect of the present disclosure, an image generation unit is provided, including a first projection module 1 for emitting first image light rays, a second projection module 2 for emitting second image light rays, and a diffuser screen 4. Among them, the first image light rays are incident on a first area of the diffuser screen 4, and the second image light rays are incident on a second area of the diffuser screen 4. The first area and the second area partially or completely overlap to form a display image source; the display image source is used to be projected onto a projection medium after passing through an optical adjustment lens group to form a virtual image within a horizontal field of view and a vertical field of view; for any point on the diffuser screen 4, the incident angles of the first image light rays and the second image light rays incident on the diffuser screen 4 do not coincide.

[0050] In the image generation unit of the present disclosure, the first projection module 1 and the second projection module 2 respectively project first image light rays and second image light rays on the diffuser screen 4 to form a display image source. The display image source can be magnified by the optical adjustment lens group of the rear head-up display and then incident on the automotive windshield 5, and after being reflected by the windshield 5, a virtual image that can be observed within the eye box range is formed in front of the human eyes.

[0051] Reference Figure 1 As shown, after being reflected by the windshield 5, the display image source forms a virtual image in front of the human eyes, and the position of the virtual image is the image plane 6. Since the first projection module 1 and the second projection module 2 can independently project different images, after being reflected by the windshield 5, the first image light rays form a first virtual image 61 on the image plane 6, and the second image light rays form a second virtual image 62 on the image plane 6. Since the monocular images are independently projected by the first projection module 1 or the second projection module 2, there will be no loss of resolution. Since the incident angles of the first image light rays and the second image light rays incident on the diffuser screen 4 do not coincide, the first image light rays and the second image light rays can respectively enter the left eye 71 and the right eye 72 (or the right eye 72 and the left eye 71) of the driver, so that the left eye 71 and the right eye 72 of the driver see different images, and three-dimensional stereoscopic display is achieved according to the binocular vision fusion effect.

[0052] For convenience, in the following exemplary description of the present disclosure, unless otherwise specified, it is assumed that the first image light rays are used to enter the left eye 71 of the driver, and the second image light rays are used to enter the right eye 72 of the driver, that is, the first virtual image 61 is a left-eye virtual image and the second virtual image 62 is a right-eye virtual image for illustration. Those skilled in the art can understand that in some other exemplary embodiments of the present disclosure, it may also be that the first image light rays are used to enter the right eye 72 of the driver, and the second image light rays are used to enter the left eye 71 of the driver, that is, the first virtual image 61 is a right-eye virtual image and the second virtual image 62 is a left-eye virtual image. Such a deformation follows the general principle of the present disclosure and does not affect the realization of the technical effects of the present disclosure.

[0053] Principle reference for stereoscopic display Figure 2 As shown, the driver's left eye 71 observes the first virtual image 61, and the right eye 72 observes the second virtual image 62. The positions of the first virtual image 61 and the second virtual image 62 are different. After the binocular images are fused, a stereoscopic image 81 is formed.

[0054] In addition, as shown in Figure 1 For the first virtual image 61 and the second virtual image 62 at different positions on the image plane 6, their positions in the line-of-sight directions of the left eye 71 and the right eye 72 are different. Therefore, the virtual image distances observed by the human eye are also different. Therefore, the image generation unit of the present disclosure can also form stereoscopic images 81 at different distances, which is beneficial to improving the fusion degree of the projected virtual image and the real scene of the head-up display, performing augmented reality, and enhancing the user experience.

[0055] For example, as shown in Figure 3 The virtual image is formed at the image plane 6 in front of the driver. The first virtual image 61 observed by the driver's left eye 71 is represented by a solid line and includes a first icon 611 in the shape of a rectangle and a second icon 612 in the shape of an arrow; the second virtual image 62 observed by the driver's right eye 72 is represented by a dotted line and includes a third icon 621 in the shape of a rectangle and a fourth icon 622 in the shape of an arrow. The first icon 611 observed by the left eye 71 and the third icon 621 observed by the right eye 72 are fused to form a first stereoscopic image 811; the second icon 612 observed by the left eye 71 and the fourth icon 622 observed by the right eye 72 are fused to form a second stereoscopic image 812. Since the positions of the first icon 611 and the second icon 612, and the third icon 621 and the fourth icon 622 in the line-of-sight directions are different, different contents of the stereoscopic image 81 are realized, and the first stereoscopic image 811 and the second stereoscopic image 812 are displayed at different virtual image distances.

[0056] Exemplarily, as shown in Figure 3As shown, for example, a virtual image is formed 5 m in front of the viewer, that is, the distance between the image plane 6 and the driver is 5 m. The first icon 611 in the shape of a rectangle observed by the driver's left eye 71 has an angle AL1 with the line of sight in the horizontal direction, and the second icon 612 in the shape of an arrow has an angle AL2 with the line of sight. Among them, AL1 = 0.1862°, AL2 = 0.5586°. The third icon 621 in the shape of a rectangle observed by the driver's right eye 72 has an angle AR1 with the line of sight in the horizontal direction, and the fourth icon 622 in the shape of an arrow has an angle AR2 with the line of sight. Among them, AR1 = -0.1862°, AR2 = 0.0266°. When the distance between the left eye 71 and the right eye 72 is 65 mm, the first stereoscopic image 811 in the shape of a rectangle formed by the fusion of the first icon 611 and the third icon 621 is located 10 m in front (65 mm / (tan AL1 - AR1) = 10 m), and the second stereoscopic image 812 in the shape of an arrow formed by the fusion of the second icon 612 and the fourth icon 622 is located 7 m in front (65 mm / (tan AL2 - AR2) = 7 m). Reference Figure 3 As shown, although the second icon 612 and the third icon 621 coincide in the spatial position of the image plane 6, however, the divergence angles of the image light rays corresponding to the second icon 612 and the third icon 621 are different and are received by the corresponding left eye 71 and right eye 72 respectively, so crosstalk will not occur.

[0057] The above only illustrates the formation principle of the first stereoscopic image 811 and the second stereoscopic image 812, that is, the formation principle of two stereoscopic images 81 with different virtual image distances. Those skilled in the art can understand that based on the above embodiments, the first virtual image 61 may further include more than two different icons, and the second virtual image 62 also includes more than two different icons corresponding to the first virtual image 61, so that the image generation unit of the present disclosure can realize the display of multiple stereoscopic images 81 at different virtual image distances. In some exemplary embodiments of the present disclosure, it is also possible to realize the display of each part of the continuous stereoscopic image 81 at different virtual image distances, that is, to realize the oblique projection display of the stereoscopic image 81. In addition, it should be noted that the image plane 6 is only the theoretical position where the virtual image is located and does not depend on the actual physical display screen.

[0058] Specifically, the first projection module 1 and the second projection module 2 are used to emit image light rays. Among them, the first projection module 1 can include various display imaging devices. For example, the display imaging device can include a liquid crystal screen, and the backlight light source of the liquid crystal screen can include one or more of a laser, a light-emitting diode, an organic light-emitting diode, a stimulated fluorescence luminescent material, and a quantum dot excitation light source; the display imaging device can also include an active light-emitting dot matrix screen composed of light-emitting dot light sources such as LEDs, MicroLEDs, OLEDs, and plasma light-emitting points; alternatively, the display imaging device can also include a projection imaging system based on projection technologies such as Digital Light Processing (DLP), Liquid Crystal on Silicon (LCoS), and Liquid Crystal Display (LCD), driven by light sources such as LEDs, MicroLEDs, OLEDs, lasers, and fluorescents or combinations thereof, reflected or transmitted by display panels such as Digital Micromirror Displays (DMDs), LCoSs, and LCDs, and then projected onto a projection screen through a projection lens for imaging; the display imaging device can also include a laser beam scanning (LBS) projection imaging system in which a laser beam scans and forms an image on a screen. The second projection module 2 can also include the above-mentioned various display imaging devices, and the structure of the second projection module 2 can be the same as or different from that of the first projection module 1.

[0059] The diffuser screen 4 can be a transmissive diffuser screen 4 or a reflective diffuser screen 4, and is used to scatter the fine light rays emitted by the first projection module 1 and the second projection module 2 at precise angles. In an exemplary embodiment of the present disclosure, the diffuser screen 4 is a transmissive diffuser screen 4, and the diffuser screen 4 is used to scatter the first image light rays transmitted through the diffuser screen 4 from the first region; the diffuser screen 4 is also used to scatter the second image light rays transmitted through the diffuser screen 4 from the second region; wherein, for any point on the diffuser screen 4, the angles at which the first image light rays and the second image light rays are transmitted through the diffuser screen 4 and exit do not coincide. On the one hand, the transmissive diffuser screen 4 plays a role in beam expansion and light homogenization for the first image light rays and the second image light rays; on the other hand, due to the reversibility of the optical path in the head-up display, sunlight may enter the head-up display in the reverse direction along the light output optical path of the head-up display and be converged by one or more reflecting mirrors of the optical adjustment lens group to the image generation unit that is the emission source of the image light rays. The diffuser screen 4 has good high-temperature resistance. The diffuser screen 4 replaces the projection modules (such as the first projection module 1 and the second projection module 2) actually used to emit image light rays as the object surface of the optical adjustment lens group, and can protect the first projection module 1 and the second projection module 2 with poor high-temperature resistance and easy to be burned by sunlight. Moreover, the transmissive diffuser screen 4 is less likely to generate stray light.

[0060] Reference Figure 4 As shown, the first region and the second region partially or completely overlap on the transmissive diffuser screen 4 to form a display image source, and the angles of the first image light and the second image light on the transmissive diffuser screen 4 do not overlap. For the subsequent optical path of the head-up display, such as the optical adjustment lens group, the display image source can be equivalent to the object image of the optical imaging system, and the diffuser screen 4 can be equivalent to the object plane of the optical imaging system.

[0061] In an exemplary embodiment of the present disclosure, the angle between the principal rays of the first image light and the principal rays of the second image light in the horizontal field of view is A, where A = 2 * atan(d / 2 / L0), d is the designed binocular distance, that is, the distance between the left eye 71 and the right eye 72 of the driver, for example, it can be 65 mm, and L0 is the object distance of the subsequent optical path of the head-up display, such as the object distance of the optical adjustment lens group, that is, the distance between the display image source and the optical principal plane of the optical adjustment lens group.

[0062] In an exemplary embodiment of the present disclosure, the scattering angle of the diffuser screen 4 for the first image light in the horizontal field of view is not greater than A; and the scattering angle of the diffuser screen 4 for the second image light in the horizontal field of view is not greater than A. Specifically, the diffuser screen 4 has a scattering effect on the first image light and the second image light, so that the divergence angles of the first image light and the second image light in the horizontal field of view are enlarged, which can ensure that when the left eye 71 and the right eye 72 of the driver move horizontally within a certain range, the corresponding first virtual image 61 and the second virtual image 62 can be seen. The scattering angles of the diffuser screen 4 for the first image light and the second image light are both less than or equal to A, which can ensure that the angles of the first image light and the second image light do not overlap when they exit from the diffuser screen 4, and prevent the first virtual image 61 from entering the right eye 72 or the second virtual image 62 from entering the left eye 71, resulting in mutual interference of the binocular images and affecting the visual effect.

[0063] Reference Figure 5 Schematic diagram showing the scattering angles and scattering regions of the diffuser screen 4 for the first image light and the second image light in the horizontal field of view direction Figure 5 In it, the solid curve represents the scattering of the diffuser screen 4 for the first image light, and the dashed curve represents the scattering of the diffuser screen 4 for the second image light; the abscissa represents the scattering angle, and the ordinate represents the scattering light intensity. From Figure 5 it can be seen that for the first image light, the light intensity outside the scattering angle A drops sharply, and the same is true for the second image light.

[0064] In an exemplary embodiment of the present disclosure, the included angle A between the chief ray of the first image light ray and the chief ray of the second image light ray in the horizontal field of view is not greater than 18.5° and not less than 6°. According to A = 2*atan(65 / 2 / L0), L0 can take values from 200 mm to 600 mm, so as to ensure that on the one hand, the internal optical path of the head-up display is not too long, so that there is enough space to arrange each optical element and it will not cause the packaging volume of the head-up display to be too large; on the other hand, it avoids the interference of each optical element due to the too short internal optical path of the head-up display. Exemplarily, the included angle A between the chief ray of the first image light ray and the chief ray of the second image light ray in the horizontal field of view can be 10.6°, and the corresponding object distance L0 can be 350 mm, which can avoid the interference of each optical element while ensuring the compact structure of the head-up display.

[0065] The divergence angle of the first image light ray and the second image light ray in the vertical field of view corresponds to the vertical direction of the driver's viewing position. Due to the different heights and postures of the driver, the position of the driver's eyes will move up and down. The width of the eye box in the vertical direction allows the position of the driver's eyes to move up and down within the eye box without affecting the driver's viewing of the virtual image projected by the head-up display. Exemplarily, the scattering angle B of the diffuser screen 4 for the first image light ray in the vertical field of view is not less than 2*atan(t / 2 / L0), where t is the designed width of the eye box in the vertical direction and L0 is the distance from the display image source to the optical principal plane of the optical adjustment lens group.

[0066] For example, when the width t of the eye box in the vertical direction is greater than or equal to 40 mm, the scattering angle B of the diffuser screen 4 for the second image light ray in the vertical field of view is greater than or equal to 2*atan(40 / 2 / L0), that is, B is greater than or equal to 3.8°. In an exemplary embodiment of the present disclosure, the scattering angle of the diffuser screen 4 for the first image light ray in the vertical field of view is not less than 4°, and the scattering angle of the diffuser screen 4 for the second image light ray in the vertical field of view is also not less than 4°, so that the driver's eyes can move within a large range in the vertical direction.

[0067] It should be noted that in fact, the scattering angles of the diffuser screen 4 for the first image light ray and the second image light ray are a spatial angle. The scattering angle in the horizontal field of view described in the present disclosure refers to the component of this spatial angle in the horizontal field of view direction for forming the virtual image, and the scattering angle in the vertical field of view refers to the component of this spatial angle in the vertical field of view direction for forming the virtual image.

[0068] In an exemplary embodiment of the present disclosure, the image generation unit further includes a synthesis unit 3. The synthesis unit 3 is configured to transmit the first image light so that the first image light passes through the synthesis unit 3 and enters the first region of the diffuser screen 4; the synthesis unit 3 is further configured to reflect the second image light so that the second image light enters the second region of the diffuser screen 4. Refer to Figure 6 As shown, the synthesis unit 3 can combine the first image light emitted by the first projection module 1 and the second image light emitted by the second projection module 2. By turning the optical path of the second image light, the synthesis unit 3 can make the spatial arrangement of the second projection module 2 more flexible and avoid interference between the spatial arrangements of the first projection module 1 and the second projection module 2.

[0069] Exemplarily, the synthesis unit 3 may include a partially reflective device 31, such as a partially transmissive and partially reflective mirror. A part of the first image light passes through the partially reflective device 31 and enters the diffuser screen 4, and a part of the first image light is reflected by the partially reflective device 31 and cannot enter the diffuser screen 4; a part of the second image light is reflected by the partially reflective device 31 and enters the diffuser screen 4, and a part of the second image light passes through the partially reflective device 31 and cannot enter the diffuser screen 4. In an exemplary embodiment of the present disclosure, the first projection module 1 and the diffuser screen 4 are disposed on opposite sides of the partially reflective device 31, and the second projection module 2 and the diffuser screen 4 are disposed on the same side of the partially reflective device 31.

[0070] In an exemplary embodiment of the present disclosure, the first image light includes light with a first polarization state, and the second image light includes light with a second polarization state; the synthesis unit 3 includes a polarization reflection device 32, such as a polarization beam splitter. The polarization reflection device 32 is configured to transmit the light with the first polarization state, and the polarization reflection device 32 is configured to reflect the light with the second polarization state.

[0071] Refer to Figure 7 As shown, for example, taking the light with the first polarization state as the linearly polarized light in the P direction and the light with the second polarization state as the linearly polarized light in the S direction as an example; the same applies when the light with the first polarization state is the linearly polarized light in the S direction and the light with the second polarization state is the linearly polarized light in the P direction. The first projection module 1 is configured to emit linearly polarized light, such as linearly polarized light in the P direction; the second projection module 2 is configured to emit linearly polarized light perpendicular to the polarization direction of the first projection module 1, such as linearly polarized light in the S direction. The polarization reflection device 32 is configured to transmit the linearly polarized light in the P direction and reflect the linearly polarized light in the S direction, so that the first image light in the P direction and the second image light in the S direction are combined and projected onto the diffuser screen 4 to form a display image source.

[0072] Exemplarily, the first image light rays may only include light rays of the first polarization state, and the second image light rays may also only include light rays of the second polarization state. That is, the first projection module 1 and the second projection module 2 may partially or entirely emit linearly polarized light. After being combined by the polarization reflection device 32, the utilization rate of light can be effectively improved without brightness loss caused by the selection effect of the synthesis unit 3 on the light rays. Exemplarily, the first image light rays and the second image light rays may not emit linearly polarized light, but instead emit circularly polarized light, elliptically polarized light, natural light, etc., as long as the first image light rays contain components of the first polarization state and the second image light rays contain components of the second polarization state. The above P direction and S direction are only reference directions for explaining the polarization directions of the first polarization state light rays and the second polarization state light rays.

[0073] As shown in the reference Figure 8 After the light rays emitted by the first projection module 1 and the second projection module 2 respectively pass through the synthesis unit 3, such as the partial reflection device 31 or the polarization reflection device 32, they are incident on the diffusion screen 4. The included angle between the principal rays of the first image light rays and the principal rays of the second image light rays in the horizontal field of view is A. After being scattered by the diffusion screen 4, the divergence angles of the first image light rays and the second image light rays increase, and then after passing through the optical adjustment lens group and the windshield 5, they can enter the left eye 71 and the right eye 72 of the driver respectively. Figure 8 In

[0074] As shown in the reference Figure 9 , Figure 9 it shows the optical path of the second image light rays from the second projection module 2 to finally entering the right eye 72 of the driver. Figure 10 It shows the schematic optical path diagram of the first image light rays and the second image light rays as a whole.

[0075] In the exemplary embodiment of the present disclosure, due to the mirrors in the optical adjustment lens group, especially the curved mirrors, the aberration in the design process of the windshield 5, and the errors formed during the processing, there may be slight differences in the image sizes and positions viewed by the left eye 71 and the right eye 72, resulting in virtual image distance errors and affecting the three-dimensional display effect. The accuracy of the three-dimensional display can be improved by separate aberration correction, virtual image distance calibration and other methods.

[0076] Exemplarily, a method for correcting aberration includes correcting the image corresponding to the left eye 71 with the image corresponding to the right eye 72 as a reference benchmark. Or correcting the image corresponding to the right eye 72 with the image corresponding to the left eye 71 as a reference benchmark.

[0077] Taking the correction of the left-eye image by the right-eye image as an example, that is, taking the displayed image of the second image light on the second projection module 2 as a reference benchmark, pre-distortion processing is performed on the displayed image of the first image light on the first projection module 1. Assuming that the displayed image of the projection module has m rows and n columns of pixels, the pixel matrix of the displayed image of the first image light on the first projection module 1 can be expressed as the matrix IL in the expression:

[0078]

[0079] Taking the pixel matrix IR of the displayed image of the second image light on the second projection module 2 as a benchmark, a distortion correction matrix C2 is introduced to correct the matrix IL. According to IR = C2 × IL, the pre-distortion data of the displayed image of the first image light on the first projection module 1 can be obtained. Similarly, taking the displayed image of the first image light on the first projection module 1 as a reference benchmark, pre-distortion processing is performed on the displayed image of the second image light on the second projection module 2, and a distortion correction matrix C1 is introduced to correct the matrix IR. According to IL = C1 × IR, the pre-distortion data of the displayed image of the second image light on the second projection module 2 can be obtained.

[0080] Exemplarily, taking the image of one eye position as the reference image, the images of the remaining eye positions are corrected. For example, first, the reference image is subjected to distortion correction according to the processing method of the above exemplary embodiment, and then the images of the remaining eye positions are subjected to distortion correction according to the processing method of the above exemplary embodiment.

[0081] According to the second aspect of the present disclosure, a head-up display is provided, including the image generation unit and the optical adjustment mirror group of any one of the above. The image generation unit is used to generate a display image source; the optical adjustment mirror group is used to project the display image source onto a projection medium to form a virtual image in the horizontal and vertical fields of view; wherein, for any point on the image plane 6 of the virtual image, the exit angles of the second virtual image light rays corresponding to the first image light ray and the second image light ray do not coincide.

[0082] The working principle of the head-up display of the present disclosure can be referred to the description of the exemplary embodiments of the aforementioned image generation unit, and will not be repeated here. The head-up display of the present disclosure will not cause loss of resolution, and since the incident angles of the first image light and the second image light on the diffusing screen 4 do not coincide, the first image light and the second image light can enter the left eye 71 and the right eye 72 (or the right eye 72 and the left eye 71) of the driver respectively, so that the left eye 71 and the right eye 72 of the driver see different images, and three-dimensional stereoscopic display is achieved according to the binocular vision fusion effect. In addition, for the first virtual image 61 and the second virtual image 62 at different positions on the image plane 6, since the positions of the first virtual image 61 and the second virtual image 62 in the line-of-sight directions of the left eye 71 and the right eye 72 are different, stereoscopic images 81 at different distances can be formed, which is beneficial to improving the fusion degree of the projected virtual image and the real scene of the head-up display, performing augmented reality, and enhancing the user experience.

[0083] Referring to Figure 11 the optical path schematic diagram of the head-up display shown, the optical adjustment mirror group may include a first reflector 91 and a second reflector 92. After the first image light and the second image light exit from the diffusing screen 4, they sequentially pass through the first reflector 91, the second reflector 92 and the windshield 5 and enter the eye box area. In an exemplary embodiment of the present disclosure, the reflecting surface of the first reflector 91 is a plane, the reflecting surface of the second reflector 92 is a concave curved surface, and the orientation of the synthesis unit 3 can be flexibly adjusted according to the spatial layout characteristics of the head-up display. Exemplarily, the synthesis unit 3 includes a polarization reflection device 32. In the vehicle coordinate system, in the vertical direction, the diffusing screen 4 is disposed above the polarization reflection device 32, and the first projection module 1 is disposed below the polarization reflection device 32; the second projection module 2 is located above the polarization reflection device 32, and the second projection module 2 is located below the second reflector 92, that is, on the side of the second reflector 92 away from the windshield 5. Exemplarily, the first reflector may also be a curved mirror.

[0084] Those skilled in the art will readily conceive of other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include known common general knowledge or conventional technical means in the technical field not disclosed by the present disclosure. The specification and examples are only to be considered as exemplary, and the true scope and spirit of the present disclosure are pointed out by the appended claims.

[0085] It should be understood that the present disclosure is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The protection scope of the present disclosure is only limited by the appended claims.

Claims

1. An image generation unit, characterized in that, It includes a first projection module (1) for emitting first image light rays, a second projection module (2) for emitting second image light rays, and a diffuser screen (4). Among them, the first image light rays are incident on a first area of the diffuser screen (4), and the second image light rays are incident on a second area of the diffuser screen (4). The first area and the second area partially or completely overlap to form a display image source. The display image source is used to be projected onto a projection medium after passing through an optical adjustment lens group to form a virtual image within a horizontal field of view and a vertical field of view. For any point on the diffuser screen (4), the incident angles of the first image light rays and the second image light rays on the diffuser screen (4) do not coincide.

2. The image generation unit according to claim 1, wherein The included angle between the principal ray of the first image light rays and the principal ray of the second image light rays within the horizontal field of view is A, where A = 2 * atan(d / 2 / L0), d is the designed binocular distance, and L0 is the distance from the display image source to the optical principal plane of the optical adjustment lens group.

3. The image generation unit according to claim 2, characterized in that The scattering angle of the diffuser screen (4) for the first image light rays within the horizontal field of view is not greater than A; and the scattering angle of the diffuser screen (4) for the second image light rays within the horizontal field of view is not greater than A.

4. The image generation unit according to claim 3, characterized in that The included angle A between the principal ray of the first image light rays and the principal ray of the second image light rays within the horizontal field of view is not greater than 18.5° and not less than 6°.

5. The image generation unit according to claim 1, wherein The scattering angle B of the diffuser screen (4) for the first image light rays within the vertical field of view is not less than 2 * atan(t / 2 / L0), where t is the designed width of the eye box in the vertical direction, and L0 is the distance from the display image source to the optical principal plane of the optical adjustment lens group.

6. The image generation unit according to claim 5, characterized in that, The scattering angle of the diffuser screen (4) for the first image light rays within the vertical field of view is not less than 4°, and the scattering angle of the diffuser screen (4) for the second image light rays within the vertical field of view is not less than 4°.

7. The image generation unit according to any one of claims 1 to 6, characterized in that, The diffuser screen (4) is a transmissive diffuser screen (4). The diffuser screen (4) is used to scatter the first image light rays transmitted through the diffuser screen (4) from the first area; the diffuser screen (4) is used to scatter the second image light rays transmitted through the diffuser screen (4) from the second area. Among them, for any point on the diffuser screen (4), the angles at which the first image light rays and the second image light rays are transmitted through the diffuser screen (4) and exit do not coincide.

8. The image generation unit according to claim 1, wherein The image generation unit further includes a synthesis unit (3). The synthesis unit (3) is used to transmit the first image light rays so that the first image light rays are incident on the first area through the synthesis unit (3); the synthesis unit (3) is further used to reflect the second image light rays so that the second image light rays are incident on the second area.

9. The image generation unit according to claim 8, wherein The synthesis unit (3) includes a partial reflection device (31). A part of the first image light rays passes through the partial reflection device (31) and is incident on the diffuser screen (4), and a part of the first image light rays is reflected by the partial reflection device (31) and cannot be incident on the diffuser screen (4). A part of the second image light is reflected by the partial reflection device (31) and enters the diffusion screen (4), and a part of the second image light passes through the partial reflection device (31) and cannot enter the diffusion screen (4).

10. The image generation unit according to claim 8, characterized in that, The first image light includes light rays in a first polarization state, and the second image light includes light rays in a second polarization state; the combining unit (3) includes a polarization reflection device (32), and the polarization reflection device (32) is configured to transmit light rays in the first polarization state, and the polarization reflection device (32) is configured to reflect light rays in the second polarization state.

11. The image generation unit according to claim 1, characterized in that, The second image light emitted by the second projection module (2) is formed after pre-distortion processing by a distortion correction matrix C1 with reference to the first image light emitted by the first projection module (1). Alternatively, the first image light emitted by the first projection module (1) is formed after pre-distortion processing by a distortion correction matrix C2 with reference to the second image light emitted by the second projection module (2).

12. A head-up display, characterized in that, It includes the image generation unit and the optical adjustment lens group according to any one of claims 1 to 11, the image generation unit is configured to generate the display image source; the optical adjustment lens group is configured to project the display image source onto the projection medium to form a virtual image within a horizontal field of view and a vertical field of view. Wherein, for any point on the image plane of the virtual image, the exit angles of the first virtual image light corresponding to the first image light and the second virtual image light corresponding to the second image light do not coincide.

Images