Projection system, head-up display system and vehicle

Abstract

The utility model discloses a projection system, a head-up display system and a vehicle. The projection system comprises an image generation unit and a diffusion screen, the image generation unit can project imaging light rays, the diffusion screen is arranged on a projection path where the image generation unit projects the imaging light rays, the diffusion screen comprises at least two diffusion parts, the diffusion screen can homogenize the imaging light rays through the diffusion parts, and the diffusion screen is configured in a manner that the image generation unit generates the imaging light rays. The at least two diffusion parts are sequentially arranged in the first direction, the distances from the at least two diffusion parts to the image generation unit in the second direction are different, the first direction is perpendicular to the second direction, and the second direction corresponds to the projection direction of the image generation unit for projecting the imaging light. According to the projection system, as the distances from different diffusion parts to the image generation unit in the second direction are different, and the image distances of images formed after the imaging light rays are emitted from the different diffusion parts are different, the distance sense that imaging is staggered front and back can be generated visually, and the 3D projection effect can be achieved easily.

Description

Technical Field

[0001] This utility model relates to the field of projection display technology, and in particular to a projection system, a head-up display system, and a vehicle. Background Technology

[0002] In recent years, Augmented Reality Head-Up Displays (AR-HUDs) have received widespread attention and rapid industrialization in the automotive electronics field. Generally, in some usage scenarios (such as road navigation), it is necessary to display images with depth information. In conventional HUD solutions, the objects imaged on the car window are flat and cannot be resolved to produce images with depth. They cannot intuitively image the longitudinal depth related to the road to the human eye, and cannot effectively combine the distance to the road ahead for display. Utility Model Content

[0003] This invention provides a projection system, a head-up display system, and a vehicle to solve at least one of the aforementioned technical problems.

[0004] This invention discloses a projection system for vehicles. The projection system includes an image generating unit and a diffusion screen. The image generating unit is capable of projecting imaging light, and the diffusion screen is disposed on the projection path of the image generating unit projecting the imaging light. The diffusion screen includes at least two diffusion sections, which can homogenize the imaging light. The diffusion screen is configured such that the at least two diffusion sections are arranged sequentially along a first direction, and the at least two diffusion sections are at different distances from the image generating unit along a second direction. The first direction is perpendicular to the second direction, and the second direction corresponds to the projection direction of the image generating unit projecting the imaging light.

[0005] In the above projection system, when the diffusion screen homogenizes the imaging light, the images formed after the imaging light is emitted from the diffusion surface of different diffusion parts in the second direction will also have different image distances due to the different distances from the different diffusion parts to the image generation unit. This will produce a sense of distance with staggered images, which is beneficial to achieving a 3D projection effect and enabling the projection imaging to be displayed according to different distances of the road position.

[0006] In one optional technical solution of this utility model, the distances from the at least two diffusion portions to the image generation unit along the second direction increase sequentially in the order of arrangement along the first direction.

[0007] In one optional technical solution of this utility model, the diffusion screen includes a diffusion screen body, and the at least two diffusion portions form an integral structure with the diffusion screen body.

[0008] In one optional technical solution of this utility model, the at least two diffusion portions are arranged in close proximity to form the diffusion screen.

[0009] In one optional technical solution of this utility model, the image generation unit includes a light source and an imaging chip. The light source can emit illumination light, and the imaging chip includes a pixel array and a pixel switch control. The pixels on the pixel array can be illuminated by the illumination light and output corresponding colored light. The pixel switch control can control the corresponding pixels on the pixel array to turn off, and the turned-off pixels do not emit light.

[0010] In one optional technical solution of this utility model, the material of the diffusion screen includes at least one of optical plastic and optical glass.

[0011] In one optional technical solution of this utility model, the light refractive index of the diffuser screen ranges from 1.43 to 1.88.

[0012] In one optional technical solution of this utility model, the intensity distribution of the light source of the image generation unit conforms to a Gaussian distribution, a near-Gaussian distribution, or a flat-top distribution.

[0013] The present invention provides a head-up display system for a vehicle. The head-up display system includes a projection system and a secondary imaging system as described in any of the above optional technical solutions. The secondary imaging system includes at least one reflector, which is disposed between the projection system and the windshield of the vehicle. The secondary imaging system is capable of reflecting the imaging light projected by the projection system so that the imaging light forms an image on the windshield.

[0014] In the aforementioned head-up display system, when the diffusion screen homogenizes the imaging light, the images formed after the imaging light is emitted from the diffusion surface of different diffusion sections in the second direction will also have different image distances due to the different distances of the different diffusion sections to the image generation unit. This will create a sense of distance with staggered images, which is beneficial to achieving a 3D projection effect and enabling the projection imaging to be displayed according to different distances of the road position.

[0015] In one optional technical solution of this utility model, the diffusion screen of the projection system is tilted relative to the first optical axis, and the first optical axis is the optical axis formed between the diffusion screen and the secondary imaging system.

[0016] In one optional technical solution of this utility model, the angle formed between the second direction and the first optical axis ranges from 7° to 18°.

[0017] In one optional technical solution of this utility model, the depth of field of the secondary imaging system can meet the following conditions:

[0018]

[0019] Wherein, F# represents the aperture number of the secondary imaging system, f represents the focal length of the secondary imaging system, δ represents the maximum allowable circle of confusion diameter, l represents the distance between the center of the diffuse screen and the entrance pupil center of the secondary imaging system, i represents the number of diffusers, h represents the height of the diffuser along the second direction, and α represents the tilt angle of the diffuse screen relative to the first optical axis, which is the optical axis formed between the diffuse screen and the secondary imaging system.

[0020] A vehicle according to this utility model includes a windshield; and a projection system as described in any of the above optional technical solutions, or a head-up display system as described in any of the above optional technical solutions.

[0021] In the aforementioned vehicle, when the diffusion screen homogenizes the imaging light, the images formed after the imaging light is emitted from the diffusion surface of different diffusion parts in the second direction will also have different image distances due to the different distances from the different diffusion parts. This will create a sense of distance with the imaging light staggered, which is beneficial for achieving a 3D projection effect and enabling the projection imaging to be displayed according to different distances of the road position.

[0022] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of this invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0024] Figure 1 This is a partial structural schematic diagram of the projection system according to an embodiment of the present utility model;

[0025] Figure 2 This is a schematic diagram of the structure of the diffusion screen according to an embodiment of the present invention;

[0026] Figure 3 This is another structural schematic diagram of the diffusion screen according to an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the image generation unit according to an embodiment of the present invention;

[0028] Figure 5 This is a partial structural schematic diagram of the head-up display system according to an embodiment of the present invention;

[0029] Figure 6 This is another structural schematic diagram of the head-up display system according to an embodiment of the present utility model;

[0030] Figure 7 This is another structural schematic diagram of the diffusion screen according to an embodiment of the present utility model;

[0031] Figure 8 This is a schematic diagram of a vehicle according to an embodiment of the present invention.

[0032] Explanation of key component symbols:

[0033] Projection system 100;

[0034] Image generation unit 110, light source 111, imaging chip 112, pixel array 113, pixel switch control 114;

[0035] Diffuser screen 120, diffuser section 121, diffuser surface 122, diffuser screen body 123, first surface 124;

[0036] Head-up display system 200; secondary imaging system 210; reflector 211;

[0037] Vehicle 300; windshield 310. Detailed Implementation

[0038] In the description of this utility model, some of the disclosed content has been shown accordingly in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The following description with reference to the accompanying drawings is exemplary and is only used to explain this utility model, and should not be construed as limiting this utility model.

[0039] In the description of this utility model, many different contents or examples are disclosed to implement different structures of this utility model. In order to simplify the disclosure of this utility model, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit this utility model.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0041] In the description of this utility model, it should be understood that the terms used to indicate orientation or positional relationship (such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc.) are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and understanding the corresponding embodiments, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to indicate orientation or positional relationship should not be construed as limitations on this utility model.

[0042] In the description of this utility model, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] Furthermore, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplification and clarity and does not in itself indicate the relationship between the various situations and / or settings discussed.

[0044] Furthermore, this invention provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0045] Please refer to Figure 1 This invention discloses a projection system 100, which can be used in vehicles. The projection system 100 may include an image generating unit 110 and a diffusion screen 120. The image generating unit 110 is capable of projecting imaging light. The diffusion screen 120 may be disposed on the projection path through which the image generating unit 110 projects the imaging light. The diffusion screen 120 may include at least two diffusion sections 121. The diffusion screen 120 is capable of homogenizing the imaging light through the diffusion sections 121.

[0046] The diffuser screen 120 can be configured such that at least two diffuser portions 121 are arranged sequentially along a first direction, and the distances from the at least two diffuser portions 121 to the image generation unit 110 along a second direction are different. The first direction is perpendicular to the second direction. The second direction corresponds to the projection direction in which the image generation unit 110 projects imaging light.

[0047] In the projection system 100 described above, when the diffusion screen 120 homogenizes the imaging light, since the distances of different diffusion sections 121 to the image generation unit 110 in the second direction are different, the images formed after the imaging light is emitted from different diffusion sections 121 will also have different image distances. This will produce a sense of distance with the imaging staggered, which is beneficial to achieving a 3D projection effect and enabling the projection imaging to be displayed according to different distances of the road position.

[0048] The diffuser screen 120 is positioned on the projection path of the image generation unit 110 to project the imaging light, so that all the imaging light projected by the image generation unit 110 will illuminate the diffuser screen 120, thereby enabling the diffuser screen 120 to homogenize all the imaging light.

[0049] Specifically, please combine Figure 1 ,exist Figure 1 In this diagram, the first direction can be represented as A1, the second direction can be represented as A2, and the projection direction of the image generation unit 110 projecting the imaging light can be represented as B1. The second direction corresponds to the projection direction of the image generation unit 110, and can be understood as the A2 direction being parallel to the B1 direction, or the A2 direction and the B1 direction forming a very small angle, making them basically parallel.

[0050] In some cases, the image generation unit 110 emits light through its internal light source 111. This light, after undergoing energy harvesting, homogenization, and shaping, illuminates the imaging chip 112 inside the image generation unit 110. The imaging chip 112 controls the emission state of the illumination light by controlling the switching of pixels, forming imaging rays capable of producing different images. These imaging rays can be projected through the direct-projection lens of the image generation unit 110. Figure 1 In this context, the imaging ray projected from the image generation unit 110 can be represented as L1.

[0051] Here, direction B1 can refer to the orientation of the direct projection lens of image generation unit 110. It should be noted that although the direct projection lens of image generation unit 110 can project imaging light along direction B1, in some cases, the incident direction of some imaging light before being projected is not parallel to the optical axis of the direct projection lens. This causes the image directly formed by the imaging light projected by image generation unit 110 to be a non-telecentric image, which will affect the observation effect, and the observer may not be able to accurately identify the information in the image.

[0052] For the diffuser screen 120, when imaging light is projected onto and passes through the diffuser screen 120, the diffuser screen 120 receives the "image" formed by the imaging light. During secondary imaging, the "image" serves as the "object" for secondary imaging. The diffuser screen 120 can homogenize the imaging light transmitted through the diffuser section 121, so that the imaging light is homogenized into a telecentric image with a relatively uniform exit angle. Figure 1 In this context, the imaging ray emitted from the diffuser screen 120 can be represented as L2.

[0053] Each diffuser portion 121 may have a diffuser surface 122. Figure 1 In this process, the diffusion surface 122 can be located on the surface of the diffusion screen 120 away from the image generation unit 110, so that when the imaging light is transmitted out of the diffusion screen 120, it will pass through the diffusion surface 122 and be homogenized by the diffusion surface 122.

[0054] It can be understood that the projection system 100 can project imaging light that can display corresponding information through the image generation unit 110, and then the imaging light projected by the image generation unit 110 can be homogenized through the diffusion screen 120. The homogenized imaging light is projected outward at the diffusion surface 122, which can be regarded as the projection system 100 outputting imaging light at the diffusion surface 122.

[0055] Generally, the output imaging rays will form an image on some reflective structures (such as the windshield of a vehicle). In this case, the image formed by the imaging rays at the diffuser surface 122 will serve as the object of the reflective structure. For the reflective structure, the following Gaussian imaging formula can be followed:

[0056]

[0057] Where x represents the focal length of the reflecting structure, u represents the object distance of the reflecting structure, and v represents the image distance of the reflecting structure.

[0058] Based on the above, for the reflective structure, its focal length is fixed and basically constant. When the object distance changes, its image distance will also change. That is, the imaging light rays will also have different image distances on the reflective structure. When the observer observes the reflective structure, it will visually form an image effect with staggered front and back and a sense of layering. This allows the imaging light rays to present three-dimensional information of different depths on the reflective structure, thereby realizing the 3D projection effect of the projection system 100.

[0059] In addition, the specific structural shape of the diffuser 120, in which the various diffuser sections 121 are arranged in a staggered manner, can be determined according to specific requirements or calibrated through actual testing.

[0060] Please refer to Figures 1 to 3 In some cases, the distance from at least two diffusers 121 to the image generation unit 110 along the second direction can be increased sequentially along the first direction.

[0061] In this way, it is easy to achieve a sense of depth in the final image formed by the imaging light.

[0062] Specifically, please combine Figure 2 and Figure 3 ,exist Figure 2 and Figure 3 In the image generation unit 110, there are four diffusion sections 121. The diffusion surfaces 122 on each diffusion section 121 can be substantially parallel to each other. All diffusion sections 121 can be arranged sequentially along the first direction. As the arrangement order of all diffusion sections 121 changes, the distance formed between the later diffusion sections 121 and the image generation unit 110 along the second direction will also increase. In other words, all diffusion sections 121 are arranged in a stepped structure on the diffusion screen 120.

[0063] It is understandable that, under the premise of ensuring the final imaging of the imaging light, setting the diffuser 120 to have the above-mentioned stepped structure allows different imaging light rays to be emitted from different diffuser sections 121, which can easily achieve a sense of layering in the final imaging of the imaging light rays. Moreover, the stepped structure is simple and easy to implement, which facilitates the production and manufacturing of the diffuser 120.

[0064] Furthermore, the first direction can be the same as the vehicle's forward orientation or the vehicle's rearward orientation. The specific orientation of the first direction can be determined based on the specific structure of the reflecting structure and the way the reflecting structure propagates the imaging light.

[0065] Please refer to Figure 2 In some cases, the diffuser 120 may include a diffuser body 123. At least two diffuser portions 121 and the diffuser body 123 may form an integral structure.

[0066] In this way, the diffuser 121 can be supported and fixed.

[0067] Specifically, please combine Figure 1 ,exist Figure 2 In this configuration, the diffuser body 123 is located between the diffuser section 121 and the image generation unit 110. The diffuser body 123 has a first surface 124. Please refer to... Figure 1 and Figure 2The first surface 124 on the diffuser body 123 faces a direction opposite to the second direction A2. The plane containing the first surface 124 can be perpendicular to the second direction A2, which makes the distance from any position on the first surface 124 to the image generation unit 110 along the second direction A2 the same. The diffuser body 123 faces the image generation unit 110 through the first surface 124, which makes the light emitted by the image generation unit 110 incident on the diffuser 120 through the first surface 124.

[0068] It can be understood that the diffuser body 123 can be regarded as a base, and the diffuser part 121 can be fixed to the base in an integral manner, which allows the diffuser body 123 to play a supporting and fixing role for the diffuser part 121. When installing and fixing the diffuser 120, only the diffuser body 123 can be contacted, thereby avoiding damage to the diffuser surface 122 when contacting the diffuser part 121.

[0069] Please refer to Figure 3 In some cases, at least two diffuser sections 121 can be arranged in close succession to form a diffuser screen 120.

[0070] This simplifies the structure of the diffuser 120 and improves space utilization.

[0071] Specifically, in Figure 3 In the image generation unit 110, the diffuser 121 can be configured as a cuboid structure. Two adjacent diffusers 121 can be in close contact through their respective edges. Each diffuser 121 can be arranged in the same orientation. The structural dimensions of each diffuser 121 can be the same. However, since the distance from each diffuser 121 to the image generation unit 110 along the second direction increases sequentially, and the thickness of each diffuser 121 along the second direction is essentially the same, the minimum distance from each diffuser 121 to the image generation unit 110 along the second direction is also different.

[0072] Understandably, in this case, the diffuser 121 can be positioned closer to the image generation unit 110, which can shorten the propagation path of the imaging light between the diffuser 121 and the image generation unit 110, and make the diffuser 121 and the image generation unit 110 more compact, thereby improving space utilization.

[0073] Please refer to Figure 4In some cases, the image generation unit 110 may include a light source 111 and an imaging chip 112. The light source 111 is capable of emitting illumination light. The imaging chip 112 may include a pixel array 113 and a pixel switch control 114. Pixels on the pixel array 113 can be illuminated by the illumination light and output corresponding colored light. The pixel switch control 114 can control the corresponding pixels on the pixel array 113 to turn off. The turned-off pixels do not emit light.

[0074] In this way, image information can be projected.

[0075] Specifically, when the light source 111 emits illumination light to the pixel array 113, the multiple pixels on the pixel array 113 will output their respective colored light, so that the pixel array 113 can output multiple colored lights, and then the multiple colored lights output by the pixel array 113 converge to form imaging light.

[0076] The imaging chip 112 may include DMD (Digital Micromirror Devices) or LCOS (Liquid Crystal on Silicon).

[0077] Furthermore, during actual assembly, due to assembly tolerances and other issues, visual effects such as discontinuities and overlaps may occur at the junction between two adjacent diffuser sections 121 on the diffuser screen 120, resulting in a poor visual experience. In this case, the image generation unit 110 can be calibrated during assembly. Specifically, the image generation unit 110 and the diffuser screen 120 are projected to form a specific image. Then, the abrupt change region with a sudden change in object distance is identified on the image, down to the specific pixel on the pixel array 113 corresponding to the abrupt change region. After calibrating the identified pixels, the image generation unit 110 is controlled using the software UI to turn off the pixels on the pixel array 113 located within and near the abrupt change region. Ultimately, this avoids the influence of light overlap or discrepancies on the final image.

[0078] In some cases, the material of the diffuser 120 may include at least one of optical plastic and optical glass.

[0079] In this way, the imaging light can be transmitted through the diffuser screen 120.

[0080] Specifically, optical plastics may include light-transmitting organic materials, and optical glass may include heavy flint glass and crown glass.

[0081] In addition, the diffusion surface 122 may be provided with microstructures arranged in a periodic or random manner. When the light emitted by the collimated light source 111 inside the image generation unit 110 passes through the diffusion surface 122, the transmitted light will diverge at a certain angle.

[0082] In some cases, the refractive index of the diffuser 120 can range from 1.43 to 1.88.

[0083] Specifically, the light refractive index of the diffuser screen 120 is greater than or equal to 1.43, which allows the light emitted from the diffuser screen 120 to still undergo total internal reflection, resulting in less information loss when projecting images; the light refractive index of the diffuser screen 120 is less than or equal to 1.88, which allows the light emitted from the diffuser screen 120 to still have a certain deflection effect, and the chromatic aberration of the image is not obvious, making it less likely to affect naked-eye observation.

[0084] The refractive index of optical plastics is generally between 1.48 and 1.7, while that of optical glass is generally between 1.43 and 1.88.

[0085] In some cases, the intensity distribution of the light source 111 of the image generation unit 110 may conform to a Gaussian distribution, a near-Gaussian distribution, or a flat-top distribution.

[0086] Please refer to Figure 5 The present invention discloses a head-up display system 200, which can be used in vehicles. The head-up display system 200 may include a secondary imaging system 210 and a projection system 100.

[0087] The secondary imaging system 210 may include at least one reflector 211. The at least one reflector 211 may be disposed between the projection system 100 and the windshield 310 of the vehicle. The secondary imaging system 210 is capable of reflecting the imaging light projected by the projection system 100 so that the imaging light is imaged on the windshield 310.

[0088] In the aforementioned head-up display system 200, when the diffusion screen 120 homogenizes the imaging light, since the distances of different diffusion sections 121 to the image generation unit 110 in the second direction are different, the images formed after the imaging light is emitted from the diffusion surface 122 on different diffusion sections 121 will also have different image distances. This will produce a sense of distance with the imaging staggered, which is beneficial to achieving a 3D projection effect and enabling the projection imaging to be displayed according to different distances of the road position.

[0089] Specifically, in Figure 5In the projection system 100, there are two reflectors 211. One reflector 211 can be located on the top side of the projection system 100, and the other reflector 211 can be located between the projection system 100 and the windshield 310. For the projection system 100, when the secondary imaging system 210 includes only one reflector 211, the output imaging light can be directly reflected on the reflector 211 and projected onto the windshield 310. When the secondary imaging system 210 includes two or more reflectors 211, the output imaging light can be reflected sequentially on all the reflectors 211 in the secondary imaging system 210 and finally projected onto the windshield 310.

[0090] exist Figure 5 In the process, the imaging light rays, after being reflected by the secondary imaging system 210, are finally projected onto the windshield 310 and form a real image (in the... Figure 5 A real image is represented as P0. When an observer observes a real image, the observer's eye is located at the observation position (in...). Figure 5 The observation position is denoted as T). Due to visual illusions, when the imaging ray that forms the real image continues to be projected from the windshield 310 towards the observation position, the real image is perceived to be on the backward extension line of the ray's projection direction. These positions will form virtual images corresponding to the imaging ray, that is... Figure 5 The images shown are P1, P2, P3, and P4.

[0091] In this situation, because different imaging rays exit from different diffusion surfaces 122, different object distances are formed for the secondary imaging system 210, resulting in different image distances in the image observed by the human eye at position T. Specifically... Figure 5 P1, P2, P3, and P4 in the image have different distances relative to position T. Therefore, in actual driving scenarios, for the driver, the virtual image formed by the imaging light and the real image of the road in front of the vehicle will overlap. This allows the driver to observe that the virtual image with front-to-back height difference has a display correlation with the position of the corresponding distance in front of the wheels, which can form a 3D projection effect. This makes it easier for the driver to assist driving based on the instruction information displayed by the head-up display system 200 through imaging light.

[0092] Based on the above, different object distances can be formed through the diffusion screen 120. When the object distance difference between two different diffusion surfaces 122 is Δu, an image distance difference Δv will also be formed between the images formed respectively. Specifically,

[0093]

[0094] Where r represents the focal length of the secondary imaging system 210, u represents the object distance before improvement, and v represents the image distance before improvement. That is, within a visual distance of Δv, depth perception will be generated.

[0095] In addition, the number of reflectors 211 in the secondary imaging system 210, and the arrangement of the reflectors 211 in the secondary imaging system 210, can be adjusted according to specific needs, or calibrated according to actual tests.

[0096] Please refer to Figure 6 In some cases, the diffusion screen 120 of the projection system 100 can be tilted relative to the first optical axis. The first optical axis is the optical axis formed between the diffusion screen 120 and the secondary imaging system 210.

[0097] In this way, visual interference caused by external light source 111 can be reduced.

[0098] Specifically, in Figure 6 In this diagram, the first optical axis can be represented as M1, and the A3 direction is parallel to the first optical axis. The planes containing all the diffusion surfaces 122 are parallel to each other. The A4 direction is parallel to the normal to the plane containing all the diffusion surfaces 122. The A3 and A4 directions form a certain angle, causing the diffusion screen 120 to be tilted relative to the first optical axis.

[0099] It is understandable that since the head-up display system 200 needs to project images onto the windshield 310, in some application scenarios, there will be some external light sources 111 (such as sunlight, lights around the vehicle, etc.) projecting light onto the windshield 310. These external light rays will be projected onto the location of the projection system 100 and reflected on the diffusion surface 122 of the diffusion screen 120.

[0100] In the above situation, the diffuser screen 120 is tilted relative to the first optical axis, so that the external light reflected on the diffuser surface 122 will not be projected into the secondary imaging system 210 along the first optical axis. This prevents the external light from propagating along the projection path of the imaging light. As a result, the image of the external light on the windshield 310 will not overlap with the image of the imaging light on the windshield 310, making it easier for the driver to identify the image of the imaging light and thus reducing visual interference caused by the external light source 111.

[0101] Additionally, in some cases, the first optical axis can be the straight line connecting the geometric center of the diffuser 120 and the center of the mirror surface of the first reflecting imaging ray 211. Figure 6 In the middle, a second optical axis can be formed between the two reflecting mirrors 211 (in Figure 6The second optical axis can be represented as M2), and a third optical axis can be formed between the reflector 211 that projects imaging rays onto the windshield 310 and the windshield 310 (in Figure 6 The third optical axis can be represented as M3). The second optical axis can be the straight line connecting the centers of the mirror surfaces of the two reflectors 211. The third optical axis can be the straight line connecting the centers of the mirror surfaces of the reflector 211 that projects imaging light onto the windshield 310 and the windshield 310.

[0102] In some cases, the angle formed between the second direction and the first optical axis can range from 7° to 18°.

[0103] Specifically, please combine Figure 1 and Figure 6 The A4 direction can be parallel to the A2 direction (i.e., the second direction). It can be understood that if the angle formed between the second direction and the first optical axis is greater than or equal to 7°, the images formed by the external light rays and the imaging light rays will not overlap; if the angle formed between the second direction and the first optical axis is less than or equal to 18°, the diffuser screen 120 will not be tilted too much and affect the imaging effect of the imaging light rays.

[0104] Under the following conditions, the depth of field of the secondary imaging system 210 can satisfy the following conditions:

[0105]

[0106] Wherein, F# represents the aperture number of the secondary imaging system 210, f represents the focal length of the secondary imaging system 210, δ represents the maximum allowable circle of confusion diameter, l represents the distance between the center of the diffuse screen 120 and the entrance pupil center of the secondary imaging system 210, i represents the number of diffuser sections 121, h represents the height of the diffuser section 121 along the second direction, and α represents the tilt angle of the diffuse screen 120 relative to the first optical axis, the first optical axis being the optical axis formed between the diffuse screen 120 and the secondary imaging system 210.

[0107] In this way, the imaging light can be clearly imaged on the windshield 310.

[0108] It can be understood that the imaging light rays are emitted from the diffuser screen 120, reflected in the secondary imaging system 210, and finally imaged on the windshield 310. That is, the image of the imaging light rays on the diffuser surface 122 can be regarded as the object of the secondary imaging system 210, and the image of the imaging light rays on the windshield 310 can be regarded as the image of the secondary imaging system 210.

[0109] Based on the above, please combine Figure 6Specifically, line M4 is parallel to the direction A4. The intersection of line M4 and line M1 is the geometric center O1 of the diffuser screen 120, and the angle between them is α.

[0110] For the secondary imaging system 210, according to the imaging principle, the depth of field of the secondary imaging system 210 is as follows:

[0111]

[0112] And, the rear depth of field of the secondary imaging system 210 is:

[0113]

[0114] The total depth of field of the secondary imaging system 210 is:

[0115]

[0116] It is understandable that, in order for the object in the secondary imaging system 210 formed by the imaging rays on the diffusion surface 122 to be sufficiently clearly imaged on the windshield 310, all diffusion surfaces 122 need to fall within the total depth of field of the secondary imaging system 210. Specifically, in Figure 6 In the diagram, along direction A3, the farthest point on the farthest diffuser 121 is denoted as N1, and the nearest point on the nearest diffuser 121 is denoted as N2. The distance between points N1 and N2 along the direction of the first optical axis is:

[0117] D = ihcosα;

[0118] D can also be considered as the maximum difference in object distance formed by the imaging rays on the diffusion screen 120.

[0119] Based on the above, the total depth of field of the secondary imaging system 210 is greater than or equal to the length of the size formed by all the diffusers 121 along the first optical axis, which allows the imaging light projected by the diffuser screen 120 at any position on it to form a sufficiently clear image on the windshield 310, thereby ensuring that the driver can identify the content in the image.

[0120] Please refer to Figure 7 The vehicle 300 of this utility model may include a windshield 310, and one of a projection system 100 and a head-up display system 200.

[0121] In the aforementioned vehicle 300, when the diffusion screen 120 homogenizes the imaging light, since the distances of different diffusion sections 121 to the image generation unit 110 in the second direction are different, the images formed after the imaging light is emitted from the diffusion surface 122 on different diffusion sections 121 will also have different image distances. This will produce a sense of distance with the imaging staggered, which is beneficial to achieving a 3D projection effect and enabling the projection imaging to be displayed in accordance with different distances of the road position.

[0122] Specifically, when the vehicle 300 includes a projection system 100, the projection system 100 can directly project the imaging light onto the windshield 310; when the vehicle 300 includes a head-up display system 200, the secondary imaging system 210 can reflect the imaging light, and the reflected imaging light can be projected onto the windshield 310.

[0123] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to the embodiments of the present invention without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A projection system for a vehicle, characterized in that, The projection system includes: An image generation unit, which is capable of projecting imaging light; and A diffusion screen is disposed on the projection path of the image generation unit on which the imaging light is projected. The diffusion screen includes at least two diffusion sections, which can homogenize the imaging light. The diffusion screen is configured such that the at least two diffusion portions are arranged sequentially along a first direction, the first direction being perpendicular to a second direction, and the second direction corresponding to the projection direction in which the image generation unit projects the imaging light.

2. The projection system according to claim 1, characterized in that, Arranged in the first direction, the distances of the at least two diffusion portions to the image generation unit increase sequentially along the second direction.

3. The projection system according to claim 2, characterized in that, The diffusion screen includes a diffusion screen body, and the at least two diffusion sections form an integral structure with the diffusion screen body.

4. The projection system according to claim 2, characterized in that, The at least two diffusers are arranged in close succession to form the diffuser screen.

5. The projection system according to claim 1, characterized in that, The image generation unit includes: A light source, the light source being capable of emitting illumination light; and An imaging chip, comprising a pixel array and a pixel switch control, wherein pixels on the pixel array can be illuminated by the illumination light and output corresponding colored light, and the pixel switch control can control the corresponding pixels on the pixel array to turn off, and the turned-off pixels do not emit light.

6. The projection system according to claim 1, characterized in that, The material of the diffusion screen includes at least one of optical plastic and optical glass.

7. The projection system according to claim 1, characterized in that, The refractive index of the diffuser screen ranges from 1.43 to 1.

88.

8. The projection system according to claim 1, characterized in that, The intensity distribution of the light source in the image generation unit conforms to a Gaussian distribution, a near-Gaussian distribution, or a flat-top distribution.

9. A head-up display system for a vehicle, characterized in that, The head-up display system includes: The projection system according to any one of claims 1 to 8; and A secondary imaging system includes at least one reflector disposed between the projection system and the windshield of the vehicle. The secondary imaging system is capable of reflecting the imaging light projected by the projection system so that the imaging light forms an image on the windshield.

10. The head-up display system according to claim 9, characterized in that, The diffusion screen of the projection system is tilted relative to the first optical axis, which is the optical axis formed between the diffusion screen and the secondary imaging system.

11. The head-up display system according to claim 10, characterized in that, The angle formed between the second direction and the first optical axis ranges from 7° to 18°.

12. The head-up display system according to claim 9, characterized in that, The depth of field of the secondary imaging system can satisfy the following conditions: Wherein, F# represents the aperture number of the secondary imaging system, f represents the focal length of the secondary imaging system, δ represents the maximum allowable circle of confusion diameter, l represents the distance between the center of the diffuse screen and the entrance pupil center of the secondary imaging system, i represents the number of diffusers, h represents the height of the diffuser along the second direction, and α represents the tilt angle of the diffuse screen relative to the first optical axis, which is the optical axis formed between the diffuse screen and the secondary imaging system.

13. A vehicle, characterized in that, The vehicles include: Windshield; and The projection system according to any one of claims 1 to 8, or the head-up display system according to any one of claims 9 to 12.

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