Projection apparatus, display device and vehicle

Abstract

A projection apparatus (110), a display device (100) and a vehicle, which relate to the technical field of display. The projection apparatus (110) comprises: a picture generation unit (20), which is used for generating picture light; and a diffuser (10), which is located on a light-emitting side of the picture generation unit (20) and is used for diffusing the picture light projected by the picture generation unit (20), wherein a light incident surface (111) of the diffuser (10) is a curved surface, and the curvature of the light incident surface (111) of the diffuser (10) is not equal to zero. In this way, the volume of the projection apparatus (110) can be reduced while the display performance is improved.

Description

Projection devices, display equipment and vehicles

[0001] This application claims priority to Chinese Patent Application No. 202422763657.5, filed on November 13, 2024, entitled "Projection Device, Display Equipment and Vehicle", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of display technology, and in particular to a projection device, display equipment, and vehicle. Background Technology

[0003] With the development of intelligent vehicle technology, head-up displays (HUDs) are installed in vehicles to improve driving safety. A HUD typically consists of a picture generation unit (PGU) and an optical system (mainly composed of various optical components, such as a diffuser and light reflectors). The picture generation unit generates the image light and projects it outwards. The optical system processes the projected image light by folding and magnifying it. The diffuser diffuses the projected image light, increasing the diffusion angle and thus expanding the eyebox. However, to ensure optimal display quality, the diffuser is relatively large, making it difficult to miniaturize the HUD itself. Summary of the Invention

[0004] This application provides a projection device, a display device, and a vehicle that improves display performance while reducing the size of the projection device.

[0005] A first aspect of this application provides a projection device, comprising: an image generating unit for generating image light; and a diffusion screen located on the light-emitting side of the image generating unit for diffusing the image light projected by the image generating unit, wherein the light-incident surface of the diffusion screen is a curved surface with a non-zero curvature.

[0006] The projection device provided in this application embodiment sets the light-incident surface of the diffuser screen as a curved surface with non-zero curvature, which can improve display performance. At the same time, the diffuser screen is small in size, so it has little impact on the size of the projection device. Therefore, setting the light-incident surface of the diffuser screen as a curved surface can improve display performance while reducing the size of the projection device, which helps to miniaturize the projection device.

[0007] In some possible implementations, the light-incident surface of the diffuser is a concave, convex surface facing the light-emitting side of the diffuser.

[0008] In some possible implementation manners, the diffuser screen satisfies: 80mm < R < ∞, where R is the curvature radius of the light incident surface of the diffuser screen, avoiding the light incident surface of the diffuser screen from being too concave, which helps to improve the imaging quality.

[0009] In some possible implementation manners, the light incident surface of the diffuser screen is a negative curved surface convex towards the image generation unit.

[0010] In some possible implementation manners, the diffuser screen satisfies: -80mm < R < ∞, where R is the curvature radius of the light incident surface of the diffuser screen, avoiding the light incident surface of the diffuser screen from being too convex, which helps to improve the imaging quality.

[0011] In some possible implementation manners, the light incident surface of the diffuser screen is a spherical surface, an aspherical surface, a cylindrical surface or a free-form surface.

[0012] In some possible implementation manners, the light incident surface of the diffuser screen is a positive cylindrical surface concave towards the light exit side of the diffuser screen, and the diffuser screen satisfies: 80mm < R < ∞, where R is the curvature radius of the light incident surface of the diffuser screen.

[0013] In some possible implementation manners, the light incident surface of the diffuser screen is a negative cylindrical surface convex towards the image generation unit, and the diffuser screen satisfies: -80mm < R < ∞, where R is the curvature radius of the light incident surface of the diffuser screen.

[0014] In some possible implementation manners, the image generation unit includes: an image source for generating image light; and a projection lens located on the light exit side of the image source and on the light incident side of the diffuser screen, and configured to project the image light generated by the image source onto the light incident surface of the diffuser screen.

[0015] In some possible implementation manners, the image source includes: a light source and a modulation device, where the modulation device is configured to modulate the light emitted by the light source to obtain image light including image information.

[0016] In some possible implementation manners, the modulation device is any one of a liquid crystal display, a liquid crystal on silicon, a digital micromirror device or a thin film transistor.

[0017] In some possible implementation manners, the projection lens satisfies: BFL ≥ 20mm, where BFL is the back focal length of the projection lens. In this way, it is possible to avoid the optical path of the projection lens from being too short, which is beneficial to the setting of the rear optical path.

[0018] In some possible implementation manners, the projection lens satisfies: BFL / R ≥ 0.25, where BFL is the back focal length of the projection lens and R is the curvature radius of the light incident surface of the diffuser screen. In this way, it is possible to effectively balance the imaging quality and the volume of the projection device.

[0019] In some possible implementation manners, the projection lens includes at least five lenses arranged along the optical axis from the object side to the image side. In this way, the imaging quality meets the requirements.

[0020] In some possible implementations, the projection lens has ten or fewer lenses. This reduces the optical path of the projection lens, which helps to reduce its size.

[0021] A second aspect of this application provides a display device, which includes a processor and a projection device as described in any of the first aspects. The processor is configured to send image data to an image generation unit so that the image generation unit generates image light.

[0022] In some possible implementations, the display device also includes a reflective device for reflecting the image light projected by the projection device to form an image.

[0023] A third aspect of this application provides a means of transportation that includes a display device as described in the second aspect.

[0024] In some possible implementations, the vehicle also includes a dashboard with display devices mounted thereon.

[0025] In some possible implementations, the vehicle also includes a windshield through which image light emitted from the display device is incident to form an image. Attached Figure Description

[0026] Figure 1 is a schematic diagram of an application scenario of the display device provided in an embodiment of this application;

[0027] Figure 2 is a schematic diagram of the structure of a display device in the related technology;

[0028] Figure 3 is a schematic diagram of the projection device in Figure 1;

[0029] Figure 4 is a schematic diagram of another projection device provided in an embodiment of this application;

[0030] Figure 5 is a schematic diagram of a projection device provided in Embodiment 1 of this application;

[0031] Figure 6 shows the spherical chromatic aberration diagram of the projection lens in Figure 5;

[0032] Figure 7 is a bokeh curve of the projection lens in Figure 5;

[0033] Figure 8 shows the distortion of the projection lens in Figure 5;

[0034] Figure 9 is a schematic diagram of a projection device provided in Embodiment 2 of this application;

[0035] Figure 10 shows the spherical chromatic aberration of the projection lens in Figure 9;

[0036] Figure 11 is a bokeh curve of the projection lens in Figure 9;

[0037] Figure 12 shows the distortion of the projection lens in Figure 9;

[0038] Figure 13 is a first structural schematic diagram of a projection device provided in Embodiment 3 of this application;

[0039] Figure 14 is a schematic diagram of the second structure of the projection device shown in Figure 13;

[0040] Figure 15 shows the spherical chromatic aberration of the projection lens in Figure 13;

[0041] Figure 16 is a bokeh curve of the projection lens in Figure 13;

[0042] Figure 17 shows the distortion of the projection lens in Figure 13;

[0043] Figure 18 is a first structural schematic diagram of a projection device provided in Embodiment 4 of this application;

[0044] Figure 19 is a schematic diagram of the second structure of the projection device shown in Figure 18;

[0045] Figure 20 is a spherical chromatic aberration diagram of the projection lens in Figure 18;

[0046] Figure 21 is a bokeh curve of the projection lens in Figure 18;

[0047] Figure 22 shows the distortion of the projection lens in Figure 18.

[0048] Explanation of reference numerals in the attached drawings: 100, display device; 110, projection device; 120, reflecting device; 10, diffuser screen; 111, light-incident surface; 112, light-exit surface; 20, image generation unit; 21, image source; 211, light source; 212, modulation device; 213, cover glass; 22, projection lens; 221, aperture; G1, first lens; G2, second lens; G3, third lens; G4, fourth lens; G5, fifth lens; G6, sixth lens; G7, seventh lens; G8, eighth lens. Detailed Implementation

[0049] The terminology used in the implementation section of this application is for the purpose of explaining specific embodiments of this application only, and is not intended to limit this application.

[0050] To facilitate understanding, the relevant technical terms involved in the embodiments of this application will first be explained and described.

[0051] Focal length, also known as focal length, is a measure of the convergence or divergence of light in an optical system. It refers to the vertical distance from the optical center of a lens or lens group to the focal plane when a scene at infinity is formed into a clear image on the focal plane.

[0052] The image side is the side where the image is located, with the lens as the boundary. The side of the lens facing the image side is the image-side surface of the lens.

[0053] The object side is the side where the modulation device (e.g., DMD) is located, and the side of the lens facing the object side is the object side surface.

[0054] Back focal length (BFL) is defined as the distance from the lens closest to the imaging plane to the modulation unit (e.g., DMD).

[0055] Optical power characterizes the ability of a lens to refract an incident parallel beam of light.

[0056] Positive focal length means that the lens has a positive focal length and has the effect of converging light.

[0057] Negative optical power means that the lens has a negative focal length, which has the effect of diverging light.

[0058] Aperture is a device used to control the amount of light passing through the lens into an electronic device. It is usually expressed in the lens using the F# (F-number) value.

[0059] The aperture number F# is a relative value derived from the lens's focal length and the lens's light-gathering diameter (the reciprocal of the relative aperture). The smaller the aperture number F#, the more light enters the lens in the same unit of time.

[0060] Axial chromatic aberration, also known as longitudinal chromatic aberration or positional chromatic aberration, occurs when a beam of light parallel to the optical axis converges at different positions after passing through a lens. This aberration is called positional chromatic aberration or axial chromatic aberration. This is because the lens images different wavelengths of light at different positions, causing the images of different colors of light to not completely overlap during the final imaging process, resulting in the dispersion of polychromatic light.

[0061] Distortion, also known as image distortion, refers to the degree of distortion in the image formed by an optical system relative to the object itself. Distortion occurs due to aperture aberration; the height of the intersection point between the principal ray from different fields of view and the Gaussian image plane after passing through the optical system is not equal to the ideal image height, and this difference is the distortion. Therefore, distortion only changes the imaging position of an off-axis object point on the ideal plane, causing distortion in the image shape, but it does not affect the image's sharpness.

[0062] This application provides a display device 100 and a vehicle, which can be a car, truck, motorcycle, bus, ship, airplane, helicopter, lawnmower, recreational vehicle, amusement park vehicle, construction equipment, tram, golf cart, train or handcart, etc., and is not particularly limited in this application embodiment.

[0063] The display device 100 can be a head-up display (HUD), a projector, etc. The HUD can be a windshield (W) HUD, an augmented reality (AR) HUD, etc. The following description uses a head-up display as an example, with the display device 100 installed on a vehicle, as shown in Figure 1. Figure 1 is a schematic diagram of an application scenario of the display device 100 provided in this embodiment.

[0064] The display device 100 projects vehicle status information, external object indications, and navigation information into the driver's field of vision, avoiding the need for the driver to look down at this information and improving driving safety. Status information includes, but is not limited to, vehicle speed, mileage, fuel level, coolant temperature, and headlight status. External object indications include, but are not limited to, safe following distance, surrounding obstacles, and reversing camera information. Navigation information includes, but is not limited to, directional arrows, distance, and travel time.

[0065] For example, if the vehicle includes a dashboard, the display device 100 can be installed in the dashboard for concealed installation. Of course, the display device 100 can also be installed in other locations on the vehicle.

[0066] As shown in Figure 1, the vehicle also includes a windshield. Image light emitted from the display device 100 is incident on the windshield to form an image. For example, the windshield reflects the image light emitted from the display device 100 to the front of the vehicle, forming a virtual image superimposed on the real environment on the outside of the vehicle, thereby enhancing the display.

[0067] Figure 2 is a schematic diagram of the structure of a display device in the related technology.

[0068] In related technologies, as shown in Figure 2, the display device 200 includes an image generation unit (PGU) 210 and a diffuser screen 220. The image generation unit 210 generates image light to form an image and projects the image light outward. The diffuser screen 220 diffuses the image light projected by the image generation unit, increasing the diffusion angle of the image light to expand the eyebox. The diffuser screen 220 has a flat panel structure, and its light-incident surface 230 is planar. To reduce the size of the display device 200, the diffuser screen 220 is relatively small, resulting in a smaller area of ​​its light-incident surface 230, which reduces the display effect. Furthermore, to ensure the display effect of the display device 200, the image generation unit 210 and the diffuser screen 220 are arranged at an angle, which restricts the spatial layout of the display device 200 and makes it difficult to reduce its size.

[0069] In view of this, the display device 100 provided in this application embodiment sets the light-incident surface 111 of the diffuser screen 10 as a curved surface with non-zero curvature, which improves display performance while reducing the size of the display device 100, thus contributing to the miniaturization of the display device 100. In addition, when the image generation unit 20 is arranged at an angle to the diffuser screen 10, the size of the display device 100 can also be reduced.

[0070] In this embodiment of the application, the display device 100 includes a processor and a projection device 110 (as shown in FIG1). The processor is used to send image data to the image generation unit 20 so that the image generation unit 20 generates image light.

[0071] The processor can be referred to as a front-end processor. A processor includes one or more processing units, such as: an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural network processing unit (NPU). These different processing units can be independent devices or integrated into one or more processors.

[0072] In some possible implementations, continuing to refer to FIG1, the display device 100 may further include a reflective device 120, which is used to reflect and image the image light projected by the projection device 110 to form an image. Specifically, as shown in FIG1, the reflective device 120 is used to reflect the image light projected by the projection device 110 onto the windshield, and the windshield reflects the image light to the outside of the vehicle to form a virtual image located in front of the vehicle.

[0073] The number of reflective devices 120 can be one (as shown in Figure 1) or more. For example, the number of reflective devices 120 can be two. Of course, the number of reflective devices 120 can also be more or less than two. When there are multiple reflective devices 120, the types of the multiple reflective devices 120 can be the same or different, or they can be partially the same.

[0074] For example, the reflecting device 120 can be a reflector, such as the curved reflector shown in FIG1.

[0075] It should be noted that, in addition to the projection device 110, processor, and reflective device 120 described above, the display device 100 may also include other components. For example, the display device 100 may also include a power module, a wireless communication module, and an I / O interface.

[0076] Figure 3 is a schematic diagram of the projection device in Figure 1.

[0077] As shown in Figure 3, the projection device 110 includes an image generation unit 20 (PGU) and a diffuser screen 10. The image generation unit 20 generates image light and projects it onto the diffuser screen 10. The diffuser screen 10 is located on the light-emitting side of the image generation unit 20 and diffuses the image light projected by the image generation unit 20 to increase the diffusion angle (spread angle) of the image light.

[0078] It should be noted that, in addition to the PGU and the diffuser screen 10, the projection device 110 may also include other optical elements. For example, a reflective element (not shown in the figure) may be provided between the diffuser screen 10 and the PGU. The reflective element is used to reflect the image light projected by the PGU to the diffuser screen 10.

[0079] The image generation unit 20 is also called an optical engine. As shown in Figure 1, the image generation unit 20 includes an image source 21 and a projection lens 22. The image source 21 is used to generate image light. The projection lens 22 is located on the light-emitting side of the image source 21 and on the light-incident side of the diffuser screen 10. The projection lens 22 is used to project the image light generated by the image source 21 onto the light-incident surface 111 of the diffuser screen 10.

[0080] In one embodiment, as shown in FIG1, the image source 21 includes a light source 211 and a modulation device 212. The modulation device 212 is used to modulate the light emitted by the light source 211 to obtain image light including image information. The modulation device 212 includes, but is not limited to, liquid crystal display (LCD), liquid crystal on silicon (LCOS), digital micromirror device (DMD), and thin film transistor (TFT).

[0081] In addition to the light source 211 and the modulation device 212, the image source 21 may also include a cover glass 213 (CG) in some embodiments. The cover glass 213 is located on the light-emitting side of the modulation device 212 and protects the modulation device 212. The number of cover glasses 213 can be one or more, and there is no limitation here.

[0082] The diffusion screen 10 is also known as a diffusion sheet, a light diffusion element, a diffusion plate, or a diffusion component. The material of the diffusion screen 10 can be polymethyl methacrylate (PMMA), polycarbonate (PC), optical glass, etc., which is not limited in this application.

[0083] As shown in FIG. 3, the diffusion screen 10 has an incident light surface 111 and an emergent light surface 112 facing away from each other. Among them, the projection lens 22 projects the image light emitted from the image source 21 onto the incident light surface 111 of the diffusion screen 10, and the image light enters the interior of the diffusion screen 10 through the incident light surface 111 and exits from the emergent light surface 112 of the diffusion screen 10.

[0084] In the embodiment of this application, as shown in FIG. 3, the incident light surface 111 of the diffusion screen 10 is a curved surface with a non-zero curvature, that is, the incident light surface 111 of the diffusion screen 10 is not a flat surface. When the volume of the diffusion screen 10 is fixed, the area of the incident light surface 111 with a curved surface structure is larger than the area of the incident light surface 111 with a flat surface structure. The larger the area of the incident light surface 111 of the diffusion screen 10, the greater the improvement in the display effect. Therefore, setting the incident light surface 111 of the diffusion screen 10 as a curved surface can improve the display performance. At the same time, the volume of the diffusion screen 10 is small, which has little impact on the volume of the projection device 110 and helps to miniaturize the projection device 110. In addition, when the diffusion screen 10 and the image generation unit 20 are arranged at an angle, the volume of the projection device 110 can also be reduced.

[0085] Among them, the incident light surface 111 of the diffusion screen 10 can be a curved surface such as a spherical surface, an aspherical surface, a cylindrical surface, or a free-form surface.

[0086] In some possible implementation manners, the incident light surface 111 of the diffusion screen 10 is a positive curved surface concave toward the emergent light side of the diffusion screen 10, that is to say, the positive curved surface is a concave surface structure with an inward groove from the incident light side to the emergent light side of the diffusion screen 10 (as shown in FIG. 3).

[0087] Since the curved surface can be a spherical surface, an aspherical surface, a cylindrical surface, or a free-form surface, etc., the incident light surface 111 of the diffusion screen 10 can be a positive curved surface such as a positive spherical surface, a positive aspherical surface, a positive cylindrical surface, or a positive free-form surface.

[0088] In one implementation manner, when the incident light surface 111 of the diffusion screen 10 is a positive curved surface, the diffusion screen 10 can satisfy: 80mm < R < ∞, where R is the radius of curvature of the incident light surface 111 of the diffusion screen 10, avoiding the incident light surface 111 of the diffusion screen 10 from being too concave and helping to improve the imaging quality.

[0089] Among them, there is no limitation on the specific value of the radius of curvature of the light incident surface 111 of the diffusion screen 10. For example, the radius of curvature of the diffusion screen 10 can be 81 mm, 50 mm, 90 mm, 100 mm, etc.

[0090] Since the positive curved surface can be a positive spherical surface, a positive aspherical surface, a positive cylindrical surface or a positive free-form surface, etc., the radius of curvature of any one of the positive spherical surface, the positive aspherical surface, the positive cylindrical surface and the positive free-form surface can satisfy: 80 mm < R < ∞.

[0091] Of course, in another embodiment, when the light incident surface 111 of the diffusion screen 10 is a positive curved surface, the radius of curvature of the light incident surface 111 of the diffusion screen 10 can also be less than or equal to 80 mm.

[0092] FIG. 4 is a schematic structural diagram of another projection device provided by an embodiment of the present application.

[0093] In some other possible implementation manners, the light incident surface 111 of the diffusion screen 10 is a negative curved surface convex toward the image generation unit 20, that is, the negative curved surface is a convex surface structure protruding outward from the light output side to the light input side of the diffusion screen 10 (as shown in FIG. 4).

[0094] Since the curved surface can be a spherical surface, an aspherical surface, a cylindrical surface or a free-form surface, etc., the light incident surface 111 of the diffusion screen 10 can be a negative curved surface such as a negative spherical surface, a negative aspherical surface, a negative cylindrical surface or a negative free-form surface.

[0095] In one embodiment, when the light incident surface 111 of the diffusion screen 10 is a negative curved surface, the diffusion screen 10 can satisfy: -80 mm < R < ∞, where R is the radius of curvature of the light incident surface 111 of the diffusion screen 10, avoiding excessive convexity of the light incident surface 111 of the diffusion screen 10, which helps to improve the imaging quality.

[0096] Among them, there is no limitation on the specific value of the radius of curvature of the light incident surface 111 of the diffusion screen 10. For example, the radius of curvature of the diffusion screen 10 can be -78 mm, -50 mm, -40 mm, -30 mm, etc.

[0097] Since the negative curved surface can be a negative spherical surface, a negative aspherical surface, a negative cylindrical surface or a negative free-form surface, etc., the radius of curvature of any one of the negative spherical surface, the negative aspherical surface, the negative cylindrical surface and the negative free-form surface can satisfy: -80 mm < R < ∞.

[0098] Of course, in another embodiment, when the light incident surface 111 of the diffusion screen 10 is a negative curved surface, the diffusion screen 10 can also satisfy: R < -80 mm.

[0099] In this embodiment, the structure of the light-emitting surface 112 of the diffuser screen 10 is not limited. In one embodiment, the light-emitting surface 112 of the diffuser screen 10 can be a curved surface, and the curvature of the light-emitting surface 112 of the diffuser screen 10 is not equal to zero. Specifically, the light-emitting surface 112 of the diffuser screen 10 can be a negative curved surface convex outward from the light-incoming side to the light-emitting side, or the light-emitting surface 112 of the diffuser screen 10 can be a positive curved surface concave inward from the light-emitting side to the light-incoming side. Furthermore, the specific type of the light-emitting surface 112 of the diffuser screen 10 can be a sphere, an aspherical surface, a cylindrical surface, or a freeform surface, etc. In another embodiment, the light-emitting surface 112 of the diffuser screen 10 can also be a plane (as shown in Figure 3 or Figure 4).

[0100] When both the light-incident surface 111 and the light-exiting surface 112 of the diffuser screen 10 are curved surfaces, the types of the light-incident surface 111 and the light-exiting surface 112 can be the same. For example, both the light-incident surface 111 and the light-exiting surface 112 can be cylindrical or spherical.

[0101] In order to match the light incident surface 111 of the diffusion screen 10 to ensure the display effect, in some possible implementations, the projection lens 22 includes at least five lenses arranged along the optical axis from the object side to the image side. For example, the projection lens 22 may include eight lenses (as shown in Figure 5). Of course, the number of lenses may be more or less than eight.

[0102] In some embodiments, the number of lenses in the projection lens 22 may be less than or equal to ten. This reduces the optical path of the projection lens 22 and helps to reduce its size.

[0103] In some embodiments, the projection lens may further include an aperture stop 221 (as shown in Figure 5), located between the fourth and fifth lenses in the direction from the image side to the object side. Of course, the aperture stop 221 may also be located in other positions, for example, between the fifth and sixth lenses in the direction from the image side to the object side.

[0104] In some possible implementations, the projection lens 22 can satisfy: BFL ≥ 20mm, where BFL is the back focal length of the projection lens 22. This avoids the optical path of the projection lens 22 being too short, which is beneficial for the setting of the back-end optical path.

[0105] The specific values ​​for the back focal length (BFL) can be 20mm, 21mm, 25mm, 28mm, etc.

[0106] In some possible implementations, the projection lens 22 can satisfy: BFL / R ≥ 0.25, where BFL is the back focal length of the projection lens 22 and R is the radius of curvature of the light-incident surface 111 of the diffuser screen 10. This effectively balances image quality and the size of the projection device 110.

[0107] The BFL / R ratio can be 0.25, 0.3, 0.5, 0.7, etc.

[0108] The specific structure of the projection device 110 provided in this application will be described below with reference to specific embodiments.

[0109] Example 1

[0110] Figure 5 is a schematic diagram of the structure of a projection device 110 provided in Embodiment 1 of this application.

[0111] The projection device 110 of Embodiment 1 of this application includes an image generation unit 20 and a diffusion screen 10. As shown in FIG. 5, the image generation unit 20 includes a projection lens 22, a cover glass 213, and a modulation device 212. The cover glass 213 is located on the light-emitting side of the modulation device 212 and on the light-incoming side of the projection lens 22. The projection lens 22 includes a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, an aperture stop 221, a fifth lens G5, a sixth lens G6, a seventh lens G7, and an eighth lens G8 arranged sequentially along the optical axis from the image side to the object side. The first lens G1 is closest to the light-incoming surface 111 of the diffusion screen 10, and the eighth lens G8 is closest to the cover glass 213. The diffusion screen 10 is located on the light-emitting side of the projection lens 22, and the light-incoming surface 111 of the diffusion screen 10 is a curved surface. Specifically, the light-incoming surface 111 of the diffusion screen 10 is spherical, and the radius of curvature R of the light-incoming surface 111 of the diffusion screen 10 is 100 mm.

[0112] The first lens G1 has positive optical power and a focal length f1 = 34.702 mm.

[0113] The second lens G2 has negative optical power, and the focal length of the second lens G2 is f2 = -16.242 mm.

[0114] The third lens G3 has negative optical power, and the focal length of the third lens G3 is f3 = -52.068 mm.

[0115] The fourth lens G4 has positive optical power and a focal length f4 = 57.277 mm.

[0116] The fifth lens G5 and the sixth lens G6 constitute a cemented lens with positive optical power, and the cemented lens f56 = 128.384 mm.

[0117] The seventh lens G7 has positive optical power, and the focal length of the seventh lens G7 is f7 = 78.874 mm.

[0118] The eighth lens G8 has positive optical power and a focal length f8 = 41.143 mm.

[0119] The back focal length (BFL) of projection lens 22 is 27.51 mm, which is greater than 20 mm, thus meeting the requirement. Additionally, BFL / R is 0.2751, which is greater than 0.25, also meeting the requirement.

[0120] Table 1 shows the optical parameters of each optical element of the projection device 110 in Embodiment 1 of this application.

[0121] Wherein, S1 is the image-side surface of the first lens G1, S2 is the object-side surface of the first lens G1, S3 is the image-side surface of the second lens G2, S4 is the object-side surface of the second lens G2, S5 is the image-side surface of the third lens G3, S6 is the object-side surface of the third lens G3, S7 is the image-side surface of the fourth lens G4, S8 is the object-side surface of the fourth lens G4, S9 is the aperture stop 221, S10 is the image-side surface of the fifth lens G5, and S11 is the image-side surface of the fifth lens G5 and the sixth lens G S12 is the image-side surface of the sixth lens G6, S13 is the image-side surface of the seventh lens G7, S14 is the object-side surface of the seventh lens G7, S15 is the image-side surface of the eighth lens G8, S16 is the object-side surface of the eighth lens G8, S17 is the image-side surface of the cover glass 213, S18 is the object-side surface of the cover glass 213, S19 to S23 are the modulation device 212, OBJ is the light-incident surface 111 of the diffuser screen 10, and ImgH is the imaging surface.

[0122] Where R is the radius of curvature of the optical element (such as a lens or cover glass 213) at the corresponding position on the optical axis, TH is the surface thickness of the optical element along the optical axis, Nd is the refractive index of each optical element when d-line is incident on it, and Vd is the Abbe number of the optical element.

[0123] Table 2 shows the optical parameters of the projection lens 22 in Figure 5.

[0124] Wherein, f1 is the focal length of the first lens G1. f2 is the focal length of the second lens G2. f3 is the focal length of the third lens G3. f4 is the focal length of the fourth lens G4. f56 is the combined focal length of the fifth lens G5 and the sixth lens G6. f7 is the focal length of the seventh lens G7. f8 is the focal length of the eighth lens G8. EFL is the focal length of the projection lens 22. EFL(1-4) is the combined focal length of the front group consisting of the first lens G1 to the fourth lens G4. EFL(5-6) is the combined focal length of the front group consisting of the fifth lens G5 to the eighth lens G8. Fno is the aperture of the projection lens 22. BFL is the back focal length of the projection lens 22.

[0125] Figure 6 shows the spherical chromatic aberration diagram of the projection lens 22 in Figure 5. In Figure 6, the vertical axis represents the normalized pupil coordinates, and the horizontal axis represents the aberration in the axial direction, in millimeters. In Figure 6, the three curves correspond to the axial aberration curves of light with a wavelength of 625 nm, 550 nm, and 455 nm after passing through the projection lens 22 in this embodiment. As can be seen from Figure 6, in this embodiment, the axial aberration is controlled within a very small range, achieving good correction.

[0126] Figure 7 shows the astigmatism field curvature of the projection lens 22 in Figure 5, and Figure 8 shows the distortion of the projection lens 22 in Figure 5. In Figure 7, S represents the field curvature value of light with a wavelength of 550 nm in the meridional image plane, and T represents the field curvature value of light with a wavelength of 550 nm in the sagittal image plane. In Figure 8, the solid line represents the distortion value of light with a center wavelength of 550 nm passing through the projection lens 22 of this embodiment. Combining Figures 7 and 8, it can be seen that the projection lens 22 provided in this embodiment controls the field curvature and distortion within the appropriate range, which can meet the usage requirements.

[0127] Example 2

[0128] Figure 9 is a schematic diagram of the structure of a projection device 110 provided in Embodiment 2 of this application.

[0129] The projection device 110 of Embodiment 2 of this application includes an image generation unit 20 and a diffusion screen 10. As shown in FIG9, the image generation unit 20 includes a projection lens 22, a cover glass 213, and a modulation device 212. The cover glass 213 is located on the light-emitting side of the modulation device 212 and on the light-incoming side of the projection lens 22. The projection lens 22 includes a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, an aperture stop 221, a fifth lens G5, a sixth lens G6, a seventh lens G7, and an eighth lens G8 arranged sequentially along the optical axis from the image side to the object side. The first lens G1 is closest to the light-incoming surface 111 of the diffusion screen 10, and the eighth lens G8 is closest to the cover glass 213. The diffusion screen 10 is located on the light-emitting side of the projection lens 22, and the light-incoming surface 111 of the diffusion screen 10 is a negative curved surface. Specifically, the light-incoming surface 111 of the diffusion screen 10 is spherical, and the radius of curvature R of the light-incoming surface 111 of the diffusion screen 10 is -100 mm.

[0130] The first lens G1 has positive optical power and a focal length f1 = 35.591 mm.

[0131] The second lens G2 has negative optical power, and the focal length of the second lens G2 is f2 = -16.482 mm.

[0132] The third lens G3 has negative optical power, and the focal length of the third lens G3 is f3 = -50.897 mm.

[0133] The fourth lens G4 has positive optical power and a focal length f4 = 50.176 mm.

[0134] The fifth lens G5 and the sixth lens G6 constitute a cemented lens with positive optical power, and the cemented lens f56 = 115.227 mm.

[0135] The seventh lens G7 has positive optical power and a focal length f7 = 86.44 mm.

[0136] The eighth lens G8 has positive optical power and a focal length f8 = 40.864 mm.

[0137] The back focal length (BFL) of projection lens 22 is 27.726 mm, which is greater than 20 mm, thus meeting the requirement. Additionally, BFL / R is 0.27726, which is greater than 0.25, also meeting the requirement.

[0138] Table 3 shows the optical parameters of each optical element of the projection device 110 in Embodiment 2 of this application.

[0139] Wherein, S1 is the image-side surface of the first lens G1, S2 is the object-side surface of the first lens G1, S3 is the image-side surface of the second lens G2, S4 is the object-side surface of the second lens G2, S5 is the image-side surface of the third lens G3, S6 is the object-side surface of the third lens G3, S7 is the image-side surface of the fourth lens G4, S8 is the object-side surface of the fourth lens G4, S9 is the aperture stop 221, S10 is the image-side surface of the fifth lens G5, and S11 is the image-side surface of the fifth lens G5 and the sixth lens G S12 is the image-side surface of the sixth lens G6, S13 is the image-side surface of the seventh lens G7, S14 is the object-side surface of the seventh lens G7, S15 is the image-side surface of the eighth lens G8, S16 is the object-side surface of the eighth lens G8, S17 is the image-side surface of the cover glass 213, S18 is the object-side surface of the cover glass 213, S19 to S23 are the modulation device 212, OBJ is the light-incident surface 111 of the diffuser screen 10, and ImgH is the imaging surface.

[0140] Where R is the radius of curvature of the optical element (such as a lens or cover glass 213) at the corresponding position on the optical axis, TH is the surface thickness of the optical element along the optical axis, Nd is the refractive index of each optical element when d-line is incident on it, and Vd is the Abbe number of the optical element.

[0141] Table 4 shows the optical parameters of the projection lens 22 in Figure 9.

[0142] Wherein, f1 is the focal length of the first lens G1. f2 is the focal length of the second lens G2. f3 is the focal length of the third lens G3. f4 is the focal length of the fourth lens G4. f56 is the combined focal length of the fifth lens G5 and the sixth lens G6. f7 is the focal length of the seventh lens G7. f8 is the focal length of the eighth lens G8. EFL is the focal length of the projection lens 22. EFL(1-4) is the combined focal length of the front group consisting of the first lens G1 to the fourth lens G4. EFL(5-6) is the combined focal length of the front group consisting of the fifth lens G5 to the eighth lens G8. Fno is the aperture of the projection lens 22. BFL is the back focal length of the projection lens 22.

[0143] Figure 10 shows the spherical chromatic aberration diagram of the projection lens 22 in Figure 9. In Figure 10, the vertical axis represents the normalized pupil coordinates, and the horizontal axis represents the aberration in the axial direction, in millimeters. In Figure 10, the three curves correspond to the axial aberration curves of light with a wavelength of 625 nm, 550 nm, and 455 nm after passing through the projection lens 22 in this embodiment. As can be seen from Figure 10, in this embodiment, the axial aberration is controlled within a very small range, achieving good correction.

[0144] Figure 11 shows the astigmatism field curvature of the projection lens 22 in Figure 9, and Figure 12 shows the distortion of the projection lens 22 in Figure 9. In Figure 11, S represents the field curvature value of light with a wavelength of 550 nm in the meridional image plane, and T represents the field curvature value of light with a wavelength of 550 nm in the sagittal image plane. In Figure 12, the solid line represents the distortion value of light with a center wavelength of 550 nm passing through the projection lens 22 of this embodiment. Combining Figures 10 and 11, it can be seen that the projection lens 22 provided in this embodiment controls the field curvature and distortion within the corresponding range, which can meet the usage requirements.

[0145] Example 3

[0146] Figure 13 is a first structural schematic diagram of a projection device 110 provided in Embodiment 3 of this application, and Figure 14 is a second structural schematic diagram of the projection device 110 shown in Figure 13. Figure 13 is a structural schematic diagram of the projection device 110 in the vertical direction and a structural schematic diagram of the projection device 110 in the horizontal direction. The horizontal and vertical directions are perpendicular to the optical axis of the projection lens 22.

[0147] The projection device 110 of Embodiment 3 of this application includes an image generation unit 20 and a diffusion screen 10. The image generation unit 20 includes a projection lens 22, a cover glass 213, and a modulation device 212. As shown in FIG13, the cover glass 213 is located on the light-emitting side of the modulation device 212 and on the light-incident side of the projection lens 22. The projection lens 22 includes a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, an aperture stop 221, a fifth lens G5, a sixth lens G6, a seventh lens G7, and an eighth lens G8 arranged sequentially along the optical axis from the image side to the object side. The first lens G1 is closest to the light-incident surface 111 of the diffusion screen 10, and the eighth lens G8 is closest to the cover glass 213. The diffusion screen 10 is located on the light-emitting side of the projection lens 22, and the light-incident surface 111 of the diffusion screen 10 is a curved surface. Among them, the light-incident surface 111 of the diffuser screen 10 is cylindrical, the radius of curvature Ry of the light-incident surface 111 in the vertical direction is 100mm, and the radius of curvature Rx of the light-incident surface 111 in the horizontal direction is infinite, that is, the curvature of the light-incident surface 111 in the horizontal direction is 0.

[0148] The first lens G1 has positive optical power and a focal length f1 = 340.283 mm.

[0149] The second lens G2 has negative optical power, and the focal length of the second lens G2 is f2 = -34.226 mm.

[0150] The third lens G3 has negative optical power, and the focal length of the third lens G3 is f3 = -19.827 mm.

[0151] The fourth lens G4 has positive optical power and a focal length f4 = 36.255 mm.

[0152] The fifth lens G5 and the sixth lens G6 constitute a cemented lens with negative optical power, which has f56 = -314.912 mm.

[0153] The seventh lens G7 has positive optical power and a focal length f7 = 47.444 mm.

[0154] The eighth lens G8 has positive optical power and a focal length f8 = 37.630 mm.

[0155] The back focal length (BFL) of projection lens 22 is 27.85 mm, which is greater than 20 mm, thus meeting the requirement. Additionally, BFL / R is 0.2785, which is greater than 0.25, also meeting the requirement.

[0156] Table 5 shows the optical parameters of each optical element of the projection device 110 of Embodiment 3 of this application.

[0157] Wherein, S1 is the image-side surface of the first lens G1, S2 is the object-side surface of the first lens G1, S3 is the image-side surface of the second lens G2, S4 is the object-side surface of the second lens G2, S5 is the image-side surface of the third lens G3, S6 is the object-side surface of the third lens G3, S7 is the image-side surface of the fourth lens G4, S8 is the object-side surface of the fourth lens G4, S9 is the aperture stop 221, S10 is the image-side surface of the fifth lens G5, and S11 is the image-side surface of the fifth lens G5 and the sixth lens G S12 is the image-side surface of the sixth lens G6, S13 is the image-side surface of the seventh lens G7, S14 is the object-side surface of the seventh lens G7, S15 is the image-side surface of the eighth lens G8, S16 is the object-side surface of the eighth lens G8, S17 is the image-side surface of the cover glass 213, S18 is the object-side surface of the cover glass 213, S19 to S23 are the modulation device 212, OBJ is the light-incident surface 111 of the diffuser screen 10, and ImgH is the imaging surface.

[0158] Where R is the radius of curvature of the optical element (such as a lens or cover glass 213) at the corresponding position on the optical axis, TH is the surface thickness of the optical element along the optical axis, Nd is the refractive index of each optical element when d-line is incident on it, and Vd is the Abbe number of the optical element.

[0159] Table 6 shows the optical parameters of the projection lens 22 in Figure 13.

[0160] Wherein, f1 is the focal length of the first lens G1. f2 is the focal length of the second lens G2. f3 is the focal length of the third lens G3. f4 is the focal length of the fourth lens G4. f56 is the combined focal length of the fifth lens G5 and the sixth lens G6. f7 is the focal length of the seventh lens G7. f8 is the focal length of the eighth lens G8. EFL is the focal length of the projection lens 22. EFL(1-4) is the combined focal length of the front group consisting of the first lens G1 to the fourth lens G4. EFL(5-6) is the combined focal length of the front group consisting of the fifth lens G5 to the eighth lens G8. Fno is the aperture of the projection lens 22. BFL is the back focal length of the projection lens 22.

[0161] Figure 15 shows the spherical chromatic aberration diagram of the projection lens 22 in Figure 13. In Figure 15, the vertical axis represents the normalized pupil coordinates, and the horizontal axis represents the aberration in the axial direction, in millimeters. In Figure 15, the three curves correspond to the axial aberration curves of light with a wavelength of 625 nm, 550 nm, and 455 nm after passing through the projection lens 22 in this embodiment. As can be seen from Figure 15, in this embodiment, the axial aberration is controlled within a very small range, achieving good correction.

[0162] Figure 16 shows the astigmatism field curvature of the projection lens 22 in Figure 13, and Figure 17 shows the distortion of the projection lens 22 in Figure 13. In Figure 16, S represents the field curvature value of light with a wavelength of 550 nm in the meridional image plane, and T represents the field curvature value of light with a wavelength of 550 nm in the sagittal image plane. In Figure 17, the solid line represents the distortion value of light with a center wavelength of 550 nm passing through the projection lens 22 of this embodiment. Combining Figures 16 and 17, it can be seen that the projection lens 22 provided in this embodiment controls the field curvature and distortion within the corresponding range, which can meet the usage requirements.

[0163] Example 4

[0164] Figure 18 is a first structural schematic diagram of a projection device 110 provided in Embodiment 4 of this application, and Figure 19 is a second structural schematic diagram of the projection device 110 shown in Figure 18. Figure 18 is a structural schematic diagram of the projection device 110 in the vertical direction, and Figure 19 is a structural schematic diagram of the projection device 110 in the horizontal direction. The horizontal and vertical directions are perpendicular to the optical axis of the projection lens 22.

[0165] The projection device 110 of Embodiment 4 of this application includes an image generation unit 20 and a diffusion screen 10. The image generation unit 20 includes a projection lens 22, a cover glass 213, and a modulation device 212. As shown in FIG18, the cover glass 213 is located on the light-emitting side of the modulation device 212 and on the light-incident side of the projection lens 22. The projection lens 22 includes a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, an aperture stop 221, a fifth lens G5, a sixth lens G6, a seventh lens G7, and an eighth lens G8 arranged sequentially along the optical axis from the image side to the object side. The first lens G1 is closest to the light-incident surface 111 of the diffusion screen 10, and the eighth lens G8 is closest to the cover glass 213. The diffusion screen 10 is located on the light-emitting side of the projection lens 22, and the light-incident surface 111 of the diffusion screen 10 is a negative curved surface. Among them, the light-incident surface 111 of the diffuser 10 is a negative cylindrical surface, the radius of curvature Ry of the light-incident surface 111 in the vertical direction is -100mm, and the radius of curvature Rx of the light-incident surface 111 in the horizontal direction is infinite, that is, the curvature of the light-incident surface 111 in the horizontal direction is 0.

[0166] The first lens G1 has positive optical power and a focal length f1 = 52.349 mm.

[0167] The second lens G2 has positive optical power and a focal length f2 = 52.075 mm.

[0168] The third lens G3 has negative optical power, and the focal length of the third lens G3 is f3 = -9.369 mm.

[0169] The fourth lens G4 has positive optical power and a focal length f4 = 37.962 mm.

[0170] The fifth lens G5 and the sixth lens G6 constitute a cemented lens with positive optical power, and the cemented lens f56 = 245.521 mm.

[0171] The seventh lens G7 has positive optical power and a focal length f7 = 54.013 mm.

[0172] The eighth lens G8 has positive optical power and a focal length f8 = 45.555 mm.

[0173] The back focal length (BFL) of projection lens 22 is 27.850 mm, which is greater than 20 mm and meets the requirement. Additionally, BFL / R is 0.2785, which is greater than 0.25 and also meets the requirement.

[0174] Table 7 shows the optical parameters of each optical element of the projection device 110 of Embodiment 3 of this application.

[0175] Wherein, S1 is the image-side surface of the first lens G1, S2 is the object-side surface of the first lens G1, S3 is the image-side surface of the second lens G2, S4 is the object-side surface of the second lens G2, S5 is the image-side surface of the third lens G3, S6 is the object-side surface of the third lens G3, S7 is the image-side surface of the fourth lens G4, S8 is the object-side surface of the fourth lens G4, S9 is the aperture stop 221, S10 is the image-side surface of the fifth lens G5, and S11 is the image-side surface of the fifth lens G5 and the sixth lens G S12 is the image-side surface of the sixth lens G6, S13 is the image-side surface of the seventh lens G7, S14 is the object-side surface of the seventh lens G7, S15 is the image-side surface of the eighth lens G8, S16 is the object-side surface of the eighth lens G8, S17 is the image-side surface of the cover glass 213, S18 is the object-side surface of the cover glass 213, S19 to S23 are the modulation device 212, OBJ is the light-incident surface 111 of the diffuser screen 10, and ImgH is the imaging surface.

[0176] Where R is the radius of curvature of the optical element (such as a lens or cover glass 213) at the corresponding position on the optical axis, TH is the surface thickness of the optical element along the optical axis, Nd is the refractive index of each optical element when d-line is incident on it, and Vd is the Abbe number of the optical element.

[0177] Table 8 shows the optical parameters of the projection lens 22 in Figure 18.

[0178] Wherein, f1 is the focal length of the first lens G1. f2 is the focal length of the second lens G2. f3 is the focal length of the third lens G3. f4 is the focal length of the fourth lens G4. f56 is the combined focal length of the fifth lens G5 and the sixth lens G6. f7 is the focal length of the seventh lens G7. f8 is the focal length of the eighth lens G8. EFL is the focal length of the projection lens 22. EFL(1-4) is the combined focal length of the front group consisting of the first lens G1 to the fourth lens G4. EFL(5-6) is the combined focal length of the front group consisting of the fifth lens G5 to the eighth lens G8. Fno is the aperture of the projection lens 22. BFL is the back focal length of the projection lens 22.

[0179] Figure 20 is a spherical chromatic aberration diagram of the projection lens 22 in Figure 18. In Figure 20, the vertical axis represents the normalized pupil coordinates, and the horizontal axis represents the aberration in the axial direction, in millimeters. In Figure 20, the three curves correspond to the axial aberration curves of light with a wavelength of 625 nm, 550 nm, and 455 nm after passing through the projection lens 22 of this embodiment. As can be seen from Figure 20, in this embodiment, the axial aberration is controlled within a very small range, achieving good correction.

[0180] Figure 21 shows the astigmatism field curvature of the projection lens 22 in Figure 18, and Figure 22 shows the distortion of the projection lens 22 in Figure 18. In Figure 21, S represents the field curvature value of light with a wavelength of 550 nm in the meridional image plane, and T represents the field curvature value of light with a wavelength of 550 nm in the sagittal image plane. In Figure 22, the solid line represents the distortion value of light with a center wavelength of 550 nm passing through the projection lens 22 of this embodiment. Combining Figures 21 and 22, it can be seen that the projection lens 22 provided in this embodiment controls the field curvature and distortion within the corresponding range, which can meet the usage requirements.

[0181] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal connection of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances. The terms "first," "second," "third," "fourth," etc. (if present) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0182] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of this application, and are not intended to limit them. Although the embodiments of this application have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A projection device, characterized in that, Comprising: An image generation unit for generating image light; A diffusion screen located on the light-emitting side of the image generation unit and for diffusing the image light projected by the image generation unit, the incident light surface of the diffusion screen being a curved surface with a non-zero curvature; Wherein, the image generation unit includes: An image source for generating the image light; A projection lens located on the light-emitting side of the image source and on the light-incident side of the diffusion screen, and for projecting the image light generated by the image source onto the incident light surface of the diffusion screen, the projection lens including at least five lenses arranged along the optical axis from the object side to the image side.

2. The projection device according to claim 1, characterized in that, The incident light surface of the diffusion screen is a positive curved surface concave towards the light-emitting side of the diffusion screen.

3. The projection device according to claim 2, characterized in that, The diffusion screen satisfies: 80mm < R < ∞, where R is the radius of curvature of the incident light surface of the diffusion screen.

4. The projection device according to claim 1, characterized in that, The incident light surface of the diffusion screen is a negative curved surface convex towards the image generation unit.

5. The projection device according to claim 4, characterized in that, The diffusion screen satisfies: -80mm < R < ∞, where R is the radius of curvature of the incident light surface of the diffusion screen.

6. The projection device according to claim 1, characterized in that, The incident light surface of the diffusion screen is a spherical surface, an aspherical surface, a cylindrical surface or a free-form surface.

7. The projection device according to claim 6, characterized in that, The incident light surface of the diffusion screen is a positive cylindrical surface concave towards the light-emitting side of the diffusion screen, the diffusion screen satisfying: 80mm < R < ∞, where R is the radius of curvature of the incident light surface of the diffusion screen.

8. The projection device according to claim 6, characterized in that, The incident light surface of the diffusion screen is a negative cylindrical surface convex towards the image generation unit, the diffusion screen satisfying: -80mm < R < ∞, where R is the radius of curvature of the incident light surface of the diffusion screen.

9. The projection device according to any one of claims 1-8, characterized in that, The image source includes: A light source; A modulation device for modulating the light emitted by the light source to obtain the image light including image information.

10. The projection device according to claim 9, characterized in that, The modulation device is any one of a liquid crystal display, a liquid crystal on silicon, a digital micromirror device or a thin film transistor.

11. The projection device according to any one of claims 1-8, characterized in that, The projection lens satisfies: BFL ≥ 20mm, where BFL is the back focal length of the projection lens.

12. The projection device according to any one of claims 1-8, characterized in that, The projection lens satisfies: BFL / R ≥ 0.25, where BFL is the back focal length of the projection lens and R is the radius of curvature of the incident light surface of the diffusion screen.

13. The projection device according to any one of claims 1-8, characterized in that, The number of lenses of the projection lens is less than or equal to ten.

14. A display device, characterized in that, Comprising a processor and a projection device according to any one of claims 1-13, the processor being configured to send image data to the image generation unit so that the image generation unit generates the image light.

15. The display device according to claim 14, characterized in that, The display device further includes: a reflection device for reflecting and imaging the image light projected by the projection device to form an image.

16. A means of transportation, characterized in that, Comprising a display device according to claim 14 or 15.

17. The means of transport according to claim 16, characterized in that, The vehicle further includes an instrument panel, and the display device is installed in the instrument panel.

18. The means of transport according to claim 17, characterized in that, The vehicle further includes a windshield, and the image light emitted by the display device is incident on the windshield to form an image.

Images