Head-up display

Abstract

The invention relates to a head-up display which is used for enabling image light rays reflected by a projection medium to enter an eye box. The head-up display comprises: an image source for emitting image light; the galvanometer comprises a first reflecting surface and a second reflecting surface, the distances between the first reflecting surface and the light emitting surface of the image source are different from those between the second reflecting surface and the light emitting surface of the image source, and the first reflecting surface and the second reflecting surface are used for reflecting image light respectively; wherein the galvanometer has a first pose and a second pose, and under the first pose, the image light reflected by the first reflecting surface enters the eye box to form a display image of a first imaging distance; and in the second pose, the image light reflected by the second reflecting surface enters the eye box to form a display image of a second imaging distance. According to the head-up display, the field angle of the vertical direction of the display picture of the head-up display can be increased, and display images with different imaging distances can be displayed.

Description

Technical Field

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

[0002] A head-up display (HUD), also known as a head-up display system, is abbreviated as HUD. Its principle is to project important driving information such as speed and navigation onto a projection medium, such as the front windshield or a synthetic mirror of a vehicle, through a designed optical path, so that the light rays reflected by the image light on the projection medium enter a preset eyebox, thereby forming a virtual image that can be viewed by a driver observing the projection medium within the eyebox range.

[0003] In the prior art, the projection distance of a head-up display, especially an augmented reality head-up display, is generally long. Although this can make the images such as navigation guidance projected have a good fusion effect with the display image, it is difficult to intuitively meet the driver's reading needs for text-based driving information, and when the vehicle distance is relatively close, the virtual image is likely to overlap with the vehicle in front, affecting the viewing effect. And shortening the projection distance will lead to a worse fusion effect. Therefore, the display screen of the head-up display can be divided into two focal planes to display images at different distances. Among them, one focal plane displays near-view images, such as information replacing the instrument like speed and mileage, and the other focal plane displays far-view images such as navigation guidance. However, the near-view image and the far-view image in the prior art have the problem of a small vertical dimension.

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

[0005] The purpose of the present disclosure is to provide a head-up display device that can increase the vertical field of view of the display screen of the head-up display.

[0006] The head-up display of the present disclosure is used to make the light rays reflected by the image light on the projection medium enter the eyebox; the head-up display includes:

[0007] An image source for emitting image light; a galvanometer, including a first reflecting surface and a second reflecting surface, the distances from the first reflecting surface and the second reflecting surface to the light-emitting surface of the image source are different, and the first reflecting surface and the second reflecting surface are used to reflect the image light respectively;

[0008] Wherein, the galvanometer has a first pose and a second pose. In the first pose, the image light reflected by the first reflecting surface enters the eyebox to form a display image with a first imaging distance; in the second pose, the image light reflected by the second reflecting surface enters the eyebox to form a display image with a second imaging distance.

[0009] In an exemplary embodiment of the present disclosure, in the first pose, the image light rays reflected by the second reflecting surface cannot enter the eye box; in the second pose, the image light rays reflected by the first reflecting surface cannot enter the eye box.

[0010] In an exemplary embodiment of the present disclosure, the direction in which the image light rays emitted from any point on the image source enter the eye box after being reflected by the first reflecting surface in the first pose is the same as the direction in which the image light rays emitted from this point enter the eye box after being reflected by the second reflecting surface in the second pose.

[0011] In an exemplary embodiment of the present disclosure, the optical path L1 of the image light rays from the image source to the first reflecting surface is less than the optical path L2 of the image light rays from the image source to the second reflecting surface, and the first reflecting surface is provided in a light-transmissive manner.

[0012] In an exemplary embodiment of the present disclosure, when the incident angle of the first reflecting surface is greater than the preset angle α, the transmittance of the first reflecting surface is higher than the transmittance of the first reflecting surface when the incident angle is less than or equal to the preset angle α.

[0013] In an exemplary embodiment of the present disclosure, the first reflecting surface reflects light rays in the first polarization direction and transmits light rays in the second polarization direction; the second reflecting surface reflects light rays in the second polarization direction; the first polarization direction is perpendicular to the second polarization direction.

[0014] In an exemplary embodiment of the present disclosure, when the incident angle of the first reflecting surface is greater than the preset angle α, the transmittance of the first reflecting surface is higher than the reflectivity of the first reflecting surface;

[0015] When the incident angle of the first reflecting surface is less than or equal to the preset angle α, the reflectivity of the first reflecting surface is higher than the transmittance of the first reflecting surface.

[0016] In an exemplary embodiment of the present disclosure, the head-up display includes a rotating mechanism for driving the galvanometer to rotate and switch between the first pose and the second pose, and the included angle between the first reflecting surface and the second reflecting surface in the first pose is equal to the included angle between the first reflecting surface and the second reflecting surface in the second pose.

[0017] In an exemplary embodiment of the present disclosure, the included angle β between the first reflecting surface in the first pose and the first reflecting surface in the second pose is not less than 2°.

[0018] In an exemplary embodiment of the present disclosure, the galvanometer includes a prism, the first reflecting surface is provided on one surface of the prism, the second reflecting surface is provided on a surface of the prism opposite to the first reflecting surface, and both the first reflecting surface and the second reflecting surface face the light-emitting surface of the image source.

[0019] In an exemplary embodiment of the present disclosure, the galvanometer mirror includes a first reflecting element and a second reflecting element. A partially reflecting and partially transmitting film is provided on the surface of the first reflecting element opposite to the light-emitting surface of the image source to form a first reflecting surface; an antireflection film is provided on the surface of the first reflecting element opposite to the light-emitting surface of the image source; a reflecting film is provided on the surface of the second reflecting element opposite to the first reflecting element to form a second reflecting surface.

[0020] In an exemplary embodiment of the present disclosure, the first reflecting surface and the second reflecting surface are not parallel, and the included angle Q is not 0.

[0021] In an exemplary embodiment of the present disclosure, the included angle between the first reflecting surface in the first pose and the second reflecting surface in the second pose is P, and the included angle between the first reflecting surface in the first pose and the first reflecting surface in the second pose is β, β = Q + P; wherein, β is not less than 8°.

[0022] The head-up display of the present disclosure can switch between a relatively near virtual image distance and a relatively far virtual image distance according to the display requirements, and can achieve a dual-screen display effect by only using the same light-emitting area of one image source, having the advantage of a compact structure. At the same time, during the switching process between near-distance imaging and far-distance imaging, the pose of the galvanometer mirror changes, which can make the vertical fields of view corresponding to the near scene and the far scene overlap when the galvanometer mirror is in the first pose and the second pose, that is, when the aperture of the head-up display remains unchanged, a larger imaging area can be obtained when displaying the near scene or the far scene, thereby improving the vertical field angle of the display screen of the head-up display. Referring to the schematic diagram of the display effect that the head-up display of the present disclosure can present, the distances of the far-scene virtual image and the near-scene virtual image are different, and the virtual image distance can be adjusted according to the requirements of the use scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings herein are incorporated into the specification and constitute a part of this 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 without creative efforts based on these drawings.

[0024] 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:

[0025] Figure 1Schematic diagram of the vertical field of view of a near virtual image and a far virtual image in the prior art;

[0026] Figure 2 Top view schematic diagram of the imaging of an exemplary embodiment of the head-up display of the present disclosure;

[0027] Figure 3 Schematic diagram of the imaging of the near virtual image of an exemplary embodiment of the head-up display of the present disclosure;

[0028] Figure 4 Schematic diagram of the imaging of the far virtual image of an exemplary embodiment of the head-up display of the present disclosure;

[0029] Figure 5 Schematic diagram of the optical path of an exemplary embodiment of the head-up display of the present disclosure;

[0030] Figure 6 Schematic diagram of the optical path of an exemplary embodiment of the head-up display of the present disclosure;

[0031] Figure 7 Schematic diagram of the galvanometer in the first pose and the second pose in an exemplary embodiment of the head-up display of the present disclosure;

[0032] Figure 8 Schematic diagram of the galvanometer in the first pose and the second pose in an exemplary embodiment of the head-up display of the present disclosure;

[0033] Figure 9 Schematic diagram of the first reflecting surface in the first pose and the second reflecting surface in the second pose in an exemplary embodiment of the head-up display of the present disclosure;

[0034] Figure 10 Schematic diagram of the image source in an exemplary embodiment of the head-up display of the present disclosure;

[0035] Figure 11 Schematic diagram of the image source in an exemplary embodiment of the head-up display of the present disclosure;

[0036] Figure 12 Schematic diagram of the interference of the near virtual image on the far virtual image;

[0037] Figure 13 Schematic diagram of the image source in an exemplary embodiment of the head-up display of the present disclosure.

[0038] Explanation of the reference numerals is as follows:

[0039] 100. Eyebox; 1. Image source; 11. Center of the near-view image source image; 12. Center of the far-view image source image; 2. Galvanometer; 21. First reflecting surface; 22. Second reflecting surface; 3. Adjusting mirror; 41. Near-view virtual image; 42. Far-view virtual image; 5. Windshield; 6. Rotating mechanism. Detailed implementation manners

[0040] Next, the technical solutions in the exemplary embodiments of the present disclosure will be clearly and completely described with reference to the accompanying drawings in the exemplary embodiments of the present disclosure. The exemplary embodiments described herein are only for illustrative purposes 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.

[0041] 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 in the field to which the present disclosure belongs. The present disclosure uses "first" and "second" 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.

[0042] Furthermore, in the description of the present disclosure, it should be understood that the orientation terms such as "upper", "lower", "front", and "rear" described in the exemplary embodiments of the present disclosure are only used to represent relative positional relationships. For convenience, the description is made based on the position and state of the head-up display during actual operation, for example, with reference to the vehicle coordinate system as a reference, or according to the angles shown in the accompanying drawings. It should not be construed as a limitation on the exemplary embodiments of the present disclosure. Those skilled in the art can know that when the absolute position of the object being described changes, the relative positional relationship may also change accordingly. For example, after rotating or replacing the viewing direction and perspective of the structure in the exemplary embodiments of the present disclosure, "upper" may also become "lower" or "left", "right", and such changes will not cause obstacles to the understanding of those skilled in the art.

[0043] To facilitate the description of the solution of the present disclosure, a possible application scenario provided by the present disclosure takes the head-up display applied to an automobile as an example. Those skilled in the art should understand that the head-up display in the exemplary embodiments of the present disclosure can also be applied to, for example, sanitation vehicles, fire trucks, and military vehicles. Of course, it can also be applied to fields such as ships and aviation. For example, it can be applied to aircraft such as fighter jets, enabling the pilot to track and aim at objects based on the assistance of the head-up display. In the exemplary embodiments of the present disclosure, the windshield 5 of the automobile is taken as an example for description as the projection medium that finally reflects the image light to the human eye.

[0044] The near view and the far view described in the present disclosure are relative to the viewing distance of the user at the eye box position. The "near-view virtual image" and the "far-view virtual image" indicate that they do not depend on an actual physical display screen. The light is divergent light or convergent light at the position of the projected image for display, and both can be understood as "virtual images".

[0045] In the prior art, in order to reduce the visual fatigue caused by the driver's eyes focusing on the virtual image of a nearby target for a long time, and to make the virtual image of the target have a higher degree of adaptation and fitting with the real world, and to superimpose the virtual image of the target and real things more perfectly, a head-up display usually has a relatively large virtual image distance (VID). For example, for an augmented reality head-up display, the virtual image distance can reach between 7.5 and 25 meters. However, if only one focal plane is used for display, it is difficult to intuitively meet the driver's reading needs for text-based driving information. Therefore, it has become an important trend to divide the display screen into two focal planes to display images at different distances. Among them, one focal plane displays near-view information, such as information replacing the instrument panel like speed and mileage, and the other focal plane is usually used to display richer and larger-area far-view information.

[0046] Meanwhile, in the application scenario of a head-up display, when the vehicle is driving at a high speed, it is usually desired that the projected virtual image distance is relatively large, that is, the virtual image screen is farther from the human eye; while when the vehicle is driving slowly or in a state of close vehicle distance such as traffic jams, it is desired that the projected virtual image distance is relatively small, that is, the virtual image screen is closer to the human eye, so as to avoid the projected image being superimposed on the vehicle in front and affecting the display effect. Therefore, there is also a need to switch the projection distance of the head-up display.

[0047] In some head-up displays in the prior art that can achieve dual-focal-plane display, the light of the image of the head-up display reflected by the projection medium enters a preset eye box 100, and two virtual images, one far and one near, are displayed in front of the driver. In the user's field of view, the far-view virtual image 42 is farther and higher in position relative to the near-view virtual image 41, and the near-view virtual image 41 is relatively closer and lower in position. Refer to Figure 1 as shown. In the field of view, for the far-view virtual image 42 and the near-view virtual image 41, since the total vertical field of view angle of the head-up display is limited, the vertical dimension of each of the far-view virtual image 42 and the near-view virtual image 41 is limited. For example, in some solutions of the prior art, the vertical field of view angle of the near-view virtual image 41 is only about 1°, and it is impossible to fully display more near-view information; and the coverage area of the far-view virtual image 42 is also limited.

[0048] Meanwhile, in the head-up displays capable of realizing dual focal plane display in the prior art, either two Picture Generation Units (PGUs) are used to respectively emit image light rays corresponding to the near-view virtual image 41 and the far-view virtual image 42; or a large-sized image generation unit is used, and its surface is divided into two regions in the direction of forming the vertical field of view angle of the head-up display to respectively emit image light rays corresponding to the near-view virtual image 41 and the far-view virtual image 42. For the solution using two image generation units, it has the disadvantages of high cost, large packaging volume, and difficult space layout; for the solution using a large-sized image generation unit and dividing different regions, it requires the image generated by the image generation unit to have a high number of pixels, and also has the disadvantage of high cost, and the large-sized image generation unit will also cause the packaging volume of the head-up display to be too large.

[0049] In view of the above problems, the present disclosure provides a head-up display that can increase the vertical field of view angle of the display screen of the head-up display. The head-up display of the present disclosure is used to make the light rays reflected by the projection medium enter the eyebox 100. The head-up display includes: an image source 1 for emitting image light rays; a galvanometer 2 including a first reflecting surface 21 and a second reflecting surface 22, the distances from the first reflecting surface 21 and the second reflecting surface 22 to the light-emitting surface of the image source 1 are different, and the first reflecting surface 21 and the second reflecting surface 22 are used to respectively reflect the image light rays; wherein, the galvanometer 2 has a first pose and a second pose, in the first pose, the image light rays reflected by the first reflecting surface 21 enter the eyebox 100; in the second pose, the image light rays reflected by the second reflecting surface 22 enter the eyebox 100.

[0050] When the head-up display of the present disclosure is working, the image light rays emitted by the image source 1 can be reflected by the first reflecting surface 21, projected onto the windshield 5, and then reflected by the windshield 5 to enter the eyebox 100, as shown in Figure 3 shown; the image light rays emitted by the image source 1 can also enter the eyebox 100 after being reflected by the second reflecting surface 22 and the windshield 5 in sequence, as shown in Figure 4 shown. Since the distances from the first reflecting surface 21 and the second reflecting surface 22 to the light-emitting surface of the image source 1 are different, the optical paths of the image light rays reflected by the first reflecting surface 21 and the image light rays reflected by the second reflecting surface 22 are different, thereby forming two images with different virtual image distances. Specifically, the image light rays reflected by the first reflecting surface form a display image with a first imaging distance, and the image light rays reflected by the second reflecting surface form a display image with a second imaging distance, that is, the near-view virtual image 41 and the far-view virtual image 42. The galvanometer 2 can be switched between the first pose and the second pose, so as to control the image light rays reflected by the first reflecting surface 21 or the second reflecting surface 22 to enter the eyebox 100, and display two virtual images with different distances in front of the driver.

[0051] The head-up display of the present disclosure can switch between a relatively short virtual image distance and a relatively long virtual image distance according to the display requirements, and can achieve a dual-screen display effect by using only the same light-emitting area of one image source 1, having the advantage of a compact structure. At the same time, during the switching process between near-distance imaging and far-distance imaging, the pose of the galvanometer 2 changes, which can cause the vertical fields of view corresponding to the near scene and the far scene to overlap when the galvanometer 2 is in the first pose and the second pose, that is, when the size of the head-up display aperture remains unchanged, a larger imaging area can be obtained when displaying the near scene or the far scene, thereby increasing the vertical field of view angle of the display screen of the head-up display. Refer to Figure 2 The top view schematic diagram of the display effect that the head-up display of the present disclosure can present shows that the distances of the far-scene virtual image 42 and the near-scene virtual image 41 are different, and the virtual image distance can be adjusted according to the requirements of the usage scenario.

[0052] Specifically, the image source 1 can be either a display imaging device or a virtual image or a real image formed by the display imaging device. For example, the display imaging device can include a liquid crystal screen, and the backlight 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-emitting dot matrix screen composed of light-emitting point light sources such as LEDs, MicroLEDs, OLEDs, and plasma light-emitting points; or, 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 fluorescence or combinations thereof, reflected or transmitted by display panels such as Digital Micromirror Display (DMD), LCoS, and LCD, and then projected onto a projection screen through a projection lens; 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.

[0053] All the above-mentioned display imaging devices, the real images or virtual images formed by one or more refractions or reflections can also be used as the image source 1.

[0054] The head-up display can also include an image adjustment unit. In order to make the image light emitted by the image source 1 be refracted several times and projected outside the head-up display, incident on the windshield 5, and magnify the size of the virtual image to a size convenient for the driver to observe, the image adjustment unit can include optical elements such as a mirror, a lens, or an optical waveguide. For example, refer toFigure 3 As shown in Figure 4 Figure 1, the image adjustment unit includes an adjustment mirror 3. Image light sequentially passes through an image source 1, a galvanometer mirror 2, and the adjustment mirror 3, and is projected onto the inner surface of a windshield 5 outside the head-up display. The adjustment mirror 3 is used to change the propagation path of the image light and the virtual image size in directions corresponding to the horizontal field of view and the vertical field of view of the head-up display, respectively. Exemplarily, the adjustment mirror 3 can be a free-form mirror. As another example, the image adjustment unit can include a first adjustment mirror and a second adjustment mirror. The image light sequentially passes through the image source 1, the galvanometer mirror 2, the first adjustment mirror, and the second adjustment mirror, and is projected onto the outside of the head-up display. The first adjustment mirror is a spherical mirror or a free-form mirror, and the second adjustment mirror is a plane mirror. The image adjustment unit can also include more adjustment mirrors 3 and lenses or optical waveguide devices for turning the optical path, adjusting the image size, or correcting aberration to improve the display quality, etc., which are not elaborated herein in the present disclosure.

[0055] Exemplarily, the optical path L1 of the image light from the image source 1 to the first reflection surface 21 is less than the optical path L2 of the image light from the image source 1 to the second reflection surface 22. Refer to Figure 3 As shown in Figure 4 Figure 1, that is, the first reflection surface 21 is located between the second reflection surface 22 and the light-emitting surface of the image source 1. After the image light exits from the image source 1, it first passes through the first reflection surface 21 and then passes through the second reflection surface 22. In an exemplary embodiment of the present disclosure, the first reflection surface 21 is provided in a light-transmissive manner, so that a part of the image light is reflected by the first reflection surface 21 and then enters the adjustment mirror 3; a part of the image light passes through the first reflection surface 21, is reflected by the second reflection surface 22, and the image light reflected by the second reflection surface 22 passes through the first reflection surface 21 again and enters the adjustment mirror 3. Since the optical path of the image light reflected by the first reflection surface 21 is shorter, it is used to form a near-view virtual image 41, and the optical path of the image light reflected by the second reflection surface 22 is longer, which is used to form a far-view virtual image 42.

[0056] In an exemplary embodiment of the present disclosure, both the first reflection surface 21 and the second reflection surface 22 face the light-emitting surface of the image source 1, and an anti-reflection film is further provided on the back side of the first reflection surface 21 to reduce the loss of image light.

[0057] In an exemplary embodiment of the present disclosure, in a first pose, the image light reflected by the second reflection surface 22 cannot enter the eye box 100; in a second pose, the image light reflected by the first reflection surface 21 cannot enter the eye box 100.

[0058] Refer to Figure 5As shown, the solid line represents the schematic diagram of the light ray reflected by the first reflecting surface 21 of the galvanometer 2 in the first pose, and the dashed line represents the schematic diagram of the light ray reflected by the second reflecting surface 22 of the galvanometer 2 in the first pose. When the galvanometer 2 is in the first pose, the image light rays emitted by the image source 1 are reflected by both the first reflecting surface 21 and the second reflecting surface 22. The image light rays reflected by the first reflecting surface 21 correspond to the eye box 100 and can form a near-view virtual image 41 in the field of view. The image light rays reflected by the second reflecting surface 22, which should form a far-view virtual image 42, are located below the image light rays reflected by the first reflecting surface 21 and cannot enter the eye box 100, so the far-view virtual image 42 cannot be observed in the field of view.

[0059] Similarly, referring to Figure 6 As shown, the dashed line represents the schematic diagram of the light ray reflected by the first reflecting surface 21 of the galvanometer 2 in the second pose, and the solid line represents the schematic diagram of the light ray reflected by the second reflecting surface 22 of the galvanometer 2 in the second pose. When in the second pose, the image light rays emitted by the image source 1 are reflected by both the first reflecting surface 21 and the second reflecting surface 22. The image light rays reflected by the second reflecting surface 22 correspond to the eye box 100 and can form a far-view virtual image 42 in the field of view. The image light rays reflected by the first reflecting surface 21, which should form a near-view virtual image 41, are located above the image light rays reflected by the second reflecting surface 22 and cannot enter the eye box 100, so the near-view virtual image 41 cannot be observed in the field of view. Thus, the change in the display distance of the virtual image can be achieved, and by changing the magnification of the image adjustment unit and the angular state of the galvanometer 2, the virtual image distance that the driver finally sees can be controlled.

[0060] In an exemplary embodiment of the present disclosure, the direction in which the image light rays emitted from any point on the image source 1 enter the eye box 100 after being reflected by the first reflecting surface 21 in the first pose is the same as the direction in which the image light rays emitted from this point enter the eye box 100 after being reflected by the second reflecting surface 22 in the second pose, where the same direction means the light rays are coaxial. Referring to Figure 7 As shown, when the galvanometer 2 is in the first pose, the image light rays emitted from any point on the image source 1 are reflected by the first reflecting surface 21 and enter the adjustment mirror 3, as shown by the solid line; when the galvanometer 2 is in the second pose, as shown by the dashed line, the image light rays emitted from the same point on the image source 1 enter the adjustment mirror 3 in the same direction after being reflected by the second reflecting surface 22. Therefore, the near-view virtual image 41 and the far-view virtual image 42 are displayed at the same position in the human eye's field of view during display, only the imaging distances are not equal. Therefore, both the near-view virtual image 41 and the far-view virtual image 42 can have a relatively large display area and field of view. In an exemplary embodiment of the present disclosure, referring to Figure 13As shown, the centers of the images displayed on the image source 1 corresponding to the near-field virtual image 41 and the far-field virtual image 42 are the near-field image source image center 11 and the far-field image source image center 12 respectively. There may also be a small range of offsets between the near-field image source image center 11 and the far-field image source image center 12, which does not affect the implementation of this solution.

[0061] In an exemplary embodiment of the present disclosure, the head-up display includes a rotation mechanism 6 for driving the galvanometer mirror 2 to rotate and switch between a first pose and a second pose. The included angle between the first reflecting surface 21 and the second reflecting surface 22 in the first pose is equal to the included angle between the first reflecting surface 21 and the second reflecting surface 22 in the second pose. Specifically, compared with the first pose, when the galvanometer mirror 2 is in the second pose, the tilt angles of both the first reflecting surface 21 and the second reflecting surface 22 change. In an exemplary embodiment of the present disclosure, through the rotation mechanism 6, the galvanometer mirror 2 rotates from the first pose to the second pose, and the rotation angle β is not less than 2°, that is, the included angle β between the first reflecting surface 21 in the first pose and the first reflecting surface 21 in the second pose is not less than 2°.

[0062] Exemplarily, the galvanometer mirror 2 includes a prism, and the first reflecting surface 21 and the second reflecting surface 22 are respectively two surfaces of the prism. That is, the first reflecting surface 21 is provided on one surface of the prism, and the second reflecting surface 22 is provided on a surface of the prism opposite to the first reflecting surface 21. The first reflecting surface 21 is the surface of the prism close to the image source 1, and both the first reflecting surface 21 and the second reflecting surface 22 can be plane, spherical, aspherical, free-form surface or other surface types. The material of the prism can be glass, optical resin, etc., and its refractive index n≠1.

[0063] Exemplarily, the galvanometer mirror 2 can also be in other structural forms. For example, the galvanometer mirror 2 can be assembled by two elements with reflecting surfaces, and the present disclosure does not make special limitations on this. Exemplarily, the galvanometer mirror 2 includes a first reflecting element and a second reflecting element. The first reflecting element and the second reflecting element can be optical substrates such as optical flat glass. A partially reflecting and partially transmitting film is provided on the surface of the first reflecting element opposite to the light-emitting surface of the image source 1 to form the first reflecting surface 21; an antireflection film is provided on the surface of the first reflecting element opposite to the light-emitting surface of the image source 1; a high-reflection film is provided on the surface of the second reflecting element opposite to the first reflecting element to form the second reflecting surface 22. Exemplarily, a partially reflecting film is deposited on the surface of the first reflecting element close to the image source 1, and both the reflectivity and the transmittance are 50%.

[0064] In an exemplary embodiment of the present disclosure, the first reflecting surface 21 reflects light rays with a first polarization direction and transmits light rays with a second polarization direction; the second reflecting surface 22 reflects light rays with a second polarization direction; the first polarization direction is perpendicular to the second polarization direction. For example, the image light rays emitted by the image source 1 are natural light, or circularly polarized light, or elliptically polarized light, or the image light rays emitted by the image source 1 are not perpendicular to both the first polarization direction and the second polarization direction; the first reflecting surface 21 may include a polarization film with a second polarization direction, and the second reflecting surface 22 may include a polarization film with a first polarization direction, so that the first reflecting surface 21 reflects the image light rays with a first polarization direction and transmits the image light rays with a second polarization direction, and the second reflecting surface 22 reflects the image light rays with a second polarization direction.

[0065] In an exemplary embodiment of the present disclosure, when the incident angle of the first reflecting surface 21 is greater than a preset angle α, the transmittance of the first reflecting surface 21 is higher than that when the incident angle is less than or equal to the preset angle α. When the galvanometer 2 is in the first pose and the second pose, the incident angles of the image light rays on the first reflecting surface 21 are different. Therefore, by coating a film layer on the first reflecting surface 21 whose transmittance is related to the incident angle, the first reflecting surface 21 can have different transmittances in the first pose and the second pose. Exemplarily, when the incident angle is greater than the preset angle α, the transmittance of the first reflecting surface 21 is higher than its reflectivity; when the incident angle is less than or equal to the preset angle α, the reflectivity of the first reflecting surface 21 is higher than its transmittance. That is, when the incident angle is greater than the preset angle α, the first reflecting surface 21 has a higher transmittance. When displaying the distant virtual image 42, the incident angle can be made greater than the preset angle α, thereby increasing the brightness of the distant virtual image 42; when the incident angle is less than or equal to the preset angle α, the first reflecting surface 21 has a higher reflectivity. When displaying the near virtual image 41, the incident angle can be made less than or equal to the preset angle α, thereby increasing the brightness of the near virtual image 41.

[0066] In another exemplary embodiment, it may also be that when the incident angle is greater than the preset angle α, the first reflecting surface 21 has a higher reflectivity, and when the incident angle is less than or equal to the preset angle α, the first reflecting surface 21 has a higher transmittance. Correspondingly, matching the requirements of displaying the near virtual image 41 or the distant virtual image 42 with the incident angle can also increase the brightness of the near virtual image 41 and the distant virtual image 42.

[0067] In an exemplary embodiment of the present disclosure, the included angle Q between the first reflecting surface 21 and the second reflecting surface 22 is not 0. Refer to Figure 8As shown. That is, the first reflecting surface 21 and the second reflecting surface 22 are not parallel. Exemplarily, taking the acute angle between the first reflecting surface 21 and the second reflecting surface 22 as the included angle Q between the first reflecting surface 21 and the second reflecting surface 22, the included angle between the first reflecting surface 21 in the first pose and the second reflecting surface 22 in the second pose is P, and the included angle between the first reflecting surface 21 in the first pose and the first reflecting surface 21 in the second pose is β, then β = Q + P.

[0068] Reference Figure 9 As shown, the distance between the first reflecting surface 21 in the first pose and the second reflecting surface 22 in the second pose is d. The included angle P and the spacing d can be pre-designed according to the distance between the near virtual image 41 and the far virtual image 42 of the head-up display and the specific focal length of the overall imaging optical path of the head-up display. Thus, by selecting the included angle P and the included angle Q, the rotation angle of the galvanometer 2 can be determined. It can be seen that through the design of the included angle Q, the rotation angle β of the galvanometer 2 can be set more flexibly. In an exemplary embodiment of the present disclosure, β is not less than 8°.

[0069] Reference Figure 9 As shown, L1 is the distance from the light-emitting surface of the image source 1 to the first reflecting surface 21, A is the reflection angle of the center point on the light-emitting surface of the image source 1 on the first reflecting surface 21 along the main light ray direction, B is the reflection angle of the center point on the light-emitting surface of the image source 1 on the second reflecting surface 22 along the main light ray direction, and d is the distance between the first reflecting surface and the second reflecting surface. Then P = A - B. Thus, the angle P determined by the angle A and the distance d can be obtained, that is, when the placement position of the galvanometer 2 is determined, the angle P can be determined.

[0070] Exemplarily, reference Figure 8 As shown, the spacing between the first reflecting surface 21 and the second reflecting surface 22 on the side close to the image source 1 is greater than the spacing on the side far from the image source 1 to form the included angle Q.

[0071] In an exemplary embodiment of the present disclosure, the half-width of the light-emitting surface of the image source 1 is b, the optical path from the light-emitting surface of the image source 1 to the first reflecting surface 21 is L1, and L1 * tan(2β) ≥ b. Reference Figure 10 And Figure 11As shown in the figure, when the head-up display needs to display a distant virtual image 42, in the second pose, the image light is reflected by the second reflecting surface 22 and finally enters the human eye to form the distant virtual image 42. According to the same light path, according to the state of the first reflecting surface 21 in the second pose, the light ray N1 emitted from the light-emitting surface of the image source 1 will also enter the eye box 100 to form a near virtual image 41, which may interfere with the distant virtual image 42. By controlling the size of the light-emitting surface of the image source 1, the actual light-emitting surface of the image source 1 is deviated from the imaginary light ray N1, so that the image light corresponding to the near virtual image 41 has a certain distance from the image boundary corresponding to the distant view image on the light-emitting surface of the image source 1, avoiding the interference of the near virtual image 41 on the distant virtual image 42. The schematic diagram of the interference of the near virtual image 41 on the distant virtual image 42 is as shown in Figure 12 the figure.

[0072] Similarly, by controlling the size of the light-emitting surface of the image source 1, it is also possible to avoid the interference of the distant virtual image 42 on the near virtual image 41 when the near virtual image 41 is formed.

[0073] In an exemplary embodiment of the present disclosure, a process of the head-up display for displaying an image may be as follows: the controller of the head-up display receives a control instruction and adjusts the pose of the galvanometer 2 and the specific content of the image at the image source 1 according to the distant view display or near view display instruction in the control instruction. Among them, the controller of the head-up display may be communicatively connected to the vehicle electronic control unit ECU to receive the control instruction from the electronic control unit. Since the specific content of the image at the image source 1 corresponding to the near virtual image 41 and the distant virtual image 42 is different, the image light generated by the image source 1 of the head-up display needs to be adjusted to match the pose of the galvanometer 2.

[0074] In an exemplary embodiment of the present disclosure, the head-up display may also simultaneously display a near view and a distant view. By quickly switching the galvanometer 2 between the first pose and the second pose and alternately imaging the near virtual image 41 and the distant virtual image 42 based on the image frame timing, the driver observing in the eye box 100 area can simultaneously observe the near virtual image 41 and the distant virtual image 42. Exemplarily, when the total number of frames displayed is 50f per second and displayed at intervals, the frame rates corresponding to the near view display and the distant view display are 25Hz respectively. When the human eye views an image with a frame rate not less than 25Hz, it can be equivalent to a continuously displayed image, that is, the simultaneous display of the distant view and the near view is achieved.

[0075] 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, which follow the general principles of the present disclosure and include known common knowledge or conventional technical means in the technical field not disclosed in the present disclosure. The specification and embodiments are only regarded as exemplary, and the true scope and spirit of the present disclosure are pointed out by the appended claims.

[0076] 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 scope of protection of the present disclosure is only limited by the appended claims.

Claims

1. A head-up display, characterized in that, the head-up display is configured to allow light rays of an image to enter an eyebox through light rays reflected by a projection medium; the head-up display includes: an image source for emitting the light rays of the image; a galvanometer mirror including a first reflection surface and a second reflection surface, wherein distances from the first reflection surface and the second reflection surface to a light-emitting surface of the image source are different, and the first reflection surface and the second reflection surface are configured to reflect the light rays of the image respectively; wherein, the galvanometer mirror has a first pose and a second pose. In the first pose, the light rays of the image reflected by the first reflection surface enter the eyebox to form a display image with a first imaging distance; in the second pose, the light rays of the image reflected by the second reflection surface enter the eyebox to form a display image with a second imaging distance.

2. The head-up display according to claim 1, characterized in that, in the first pose, the light rays of the image reflected by the second reflection surface cannot enter the eyebox; in the second pose, the light rays of the image reflected by the first reflection surface cannot enter the eyebox.

3. The head-up display according to claim 1, characterized in that, a direction in which light rays of the image emitted from any point on the image source enter the eyebox after being reflected by the first reflection surface in the first pose is the same as a direction in which the light rays of the image emitted from the same point enter the eyebox after being reflected by the second reflection surface in the second pose.

4. The head-up display according to any one of claims 1 to 3, characterized in that, an optical path L1 of the light rays of the image from the image source to the first reflection surface is less than an optical path L2 of the light rays of the image from the image source to the second reflection surface, and the first reflection surface is provided in a light-transmissive manner.

5. The head-up display according to claim 4, characterized in that, when an incident angle is greater than a preset angle α, a transmittance of the first reflection surface is higher than a transmittance of the first reflection surface when the incident angle is less than or equal to the preset angle α.

6. The head-up display according to claim 5, characterized in that, when the incident angle is greater than the preset angle α, the transmittance of the first reflection surface is higher than a reflectance of the first reflection surface; when the incident angle is less than or equal to the preset angle α, the reflectance of the first reflection surface is higher than the transmittance of the first reflection surface.

7. The head-up display according to claim 4, characterized in that, the first reflection surface reflects light rays in a first polarization direction and transmits light rays in a second polarization direction, and the second reflection surface reflects light rays in the second polarization direction; the first polarization direction is perpendicular to the second polarization direction.

8. The head-up display according to claim 1, characterized in that, the head-up display includes a rotation mechanism for driving the galvanometer mirror to rotate and switch between the first pose and the second pose, and an included angle between the first reflection surface and the second reflection surface in the first pose is equal to an included angle between the first reflection surface and the second reflection surface in the second pose.

9. The head-up display according to claim 8, characterized in that, The included angle β between the first reflecting surface in the first pose and the first reflecting surface in the second pose is not less than 2°.

10. The head-up display according to claim 9, wherein, the galvanometer mirror includes a prism, the first reflecting surface is disposed on one surface of the prism, the second reflecting surface is disposed on a surface of the prism opposite to the first reflecting surface, and both the first reflecting surface and the second reflecting surface face the light-emitting surface of the image source.

11. The head-up display according to claim 8, wherein, the galvanometer mirror includes a first reflecting element and a second reflecting element. A partially reflecting and partially transmitting film is disposed on the surface of the first reflecting element opposite to the light-emitting surface of the image source to form the first reflecting surface; an antireflection film is disposed on the surface of the first reflecting element opposite to the light-emitting surface of the image source; a reflecting film is disposed on the surface of the second reflecting element opposite to the first reflecting element to form the second reflecting surface.

12. The head-up display according to claim 1, wherein, the first reflecting surface and the second reflecting surface are not parallel, and the included angle Q is not 0.

13. The head-up display according to claim 12, wherein, the included angle between the first reflecting surface in the first pose and the second reflecting surface in the second pose is P, the included angle between the first reflecting surface in the first pose and the first reflecting surface in the second pose is β, and β = Q + P; wherein, β is not less than 8°.

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