Rear-projection display and vehicle

Abstract

The application discloses a rear projection display and a vehicle, and relates to the technical field of displays, wherein the rear projection display comprises a light source, a projection lens group and a rear projection screen. The light source is used for generating image light carrying image information. The projection lens group is arranged on the light emitting side of the light source to receive the image light. The rear projection screen is in a curved shape; the rear projection screen is arranged on the side of the projection lens group away from the light source; the concave side of the rear projection screen faces the projection lens group; and the projection lens group is used for imaging the image information on the rear projection screen. The technical scheme provided by the application can improve the response speed of the display.

Description

Rear projection displays and vehicles Technical Field

[0001] This invention relates to the field of display technology, and in particular to a rear projection display and a vehicle. Background Technology

[0002] In vehicles, displays are used to better convey information to drivers and passengers. Since occupants are in different positions within the vehicle, the normal to the display screen's surface needs to be pointed towards a specific person to ensure accurate information delivery. However, the display screen's rotation mechanism is mechanical; once fixed at a certain angle, it cannot transmit information in other directions, and its limited rotation speed results in a slow response time, making it unable to adapt to rapidly changing display needs. Summary of the Invention

[0003] The main objective of this invention is to provide a rear projection display and a vehicle that aims to improve the display's response speed.

[0004] To achieve the above objectives, the present invention proposes a rear-projection display, comprising a light source, a projection lens assembly, and a rear-projection screen. The light source generates image light carrying image information. The projection lens assembly is disposed on the light-emitting side of the light source to receive the image light. The rear-projection screen is curved; it is disposed on the side of the projection lens assembly facing away from the light source; the concave side of the rear-projection screen faces the projection lens assembly; the projection lens assembly projects the image information onto the rear-projection screen.

[0005] In some embodiments, the concave side of the rear projection screen is the imaging surface, and the projection lens group is used to image the image information onto the imaging surface; the imaging surface is provided with a diffusion texture, the feature size of the diffusion texture is less than or equal to 5μm, and the surface roughness of the imaging surface is less than or equal to 2μm.

[0006] In some embodiments, the convex side of the rear projection screen is a parallax surface; a parallax barrier grating is provided on the parallax surface.

[0007] In some embodiments, the rear projection screen is spherical, ellipsoidal, or cylindrical.

[0008] In some embodiments, the light source is a display screen, and the position of the optical axis passing through the projection lens group on the display screen is the center of the display screen; the projection lens group is used to project a straight line passing through the center of the display screen onto a meridian of the rear projection screen; the meridian of the rear projection screen intersects the position of the rear projection screen passing through the optical axis of the projection lens group.

[0009] In some embodiments, the focal length of the projection lens group is greater than or equal to 1.4 mm and less than or equal to 5 mm; and / or

[0010] The rear projection screen has a display angle greater than or equal to 180° and less than or equal to 240°; and / or

[0011] The diameter of the rear projection screen is greater than or equal to 80mm and less than or equal to 130mm; and / or

[0012] The total optical length of the projection lens assembly is greater than or equal to 40 mm and less than or equal to 70 mm; and / or

[0013] The rear projection display has an MTF70 greater than or equal to 50%, or an MTF110 greater than or equal to 30%.

[0014] In some embodiments, the number of lenses with optical power in the projection lens group is 9, 10, 11, or 12.

[0015] In some embodiments, the side of the projection lens group facing the light source is the image side; the side of the projection lens group facing the rear projection screen is the object side; the projection lens group includes a first meniscus lens with its convex surface facing the rear projection screen, a second plano-concave lens with its plane facing the rear projection screen, a third biconcave lens, a fourth plano-convex lens with its plane facing the rear projection screen, a fifth meniscus lens with its concave surface facing the rear projection screen, a sixth biconcave lens, a seventh biconvex lens, an eighth biconvex lens, and a ninth meniscus lens with its convex surface facing the rear projection screen, arranged from the object side to the image side.

[0016] In some embodiments, the curvature of the object-side surface of the first meniscus lens is greater than or equal to 18.3139 and less than or equal to 18.3443; the curvature of the image-side surface of the first meniscus lens is greater than or equal to 13.7802 and less than or equal to 13.8072; and / or

[0017] The curvature of the image-side surface of the second plano-concave lens is greater than or equal to 7.3390 and less than or equal to 8.2117; and / or

[0018] The curvature of the object-side surface of the third biconcave lens is greater than or equal to 8.3677 and less than or equal to 8.8656; the curvature of the image-side surface of the third biconcave lens is greater than or equal to 22.1583 and less than or equal to 25.2139; and / or

[0019] The curvature of the image-side surface of the fourth plano-convex lens is greater than or equal to 9.1273 and less than or equal to 10.6210; and / or

[0020] The curvature of the object-side surface of the fifth meniscus lens is greater than or equal to 17.6516 and less than or equal to 20.1569; the curvature of the image-side surface of the fifth meniscus lens is greater than or equal to 33.2025 and less than or equal to 35.2493; and / or

[0021] The curvature of the object-side surface of the sixth biconcave lens is greater than or equal to 10.3510 and less than or equal to 11.393; the curvature of the image-side surface of the sixth biconcave lens is greater than or equal to 46.7441 and less than or equal to 86.8944; and / or

[0022] The curvature of the object-side surface of the seventh biconvex lens is greater than or equal to 46.7441 and less than or equal to 86.8944; the curvature of the image-side surface of the seventh biconvex lens is greater than or equal to 9.9202 and less than or equal to 11.0307; and / or

[0023] The curvature of the object-side surface of the eighth biconvex lens is greater than or equal to 76.3248 and less than or equal to 258.8315; the curvature of the image-side surface of the eighth biconvex lens is greater than or equal to 20.0161 and less than or equal to 22.7941; and / or

[0024] The curvature of the object side of the ninth meniscus lens is greater than or equal to 14.1233 and less than or equal to 15.5154; the curvature of the image side of the ninth meniscus lens is greater than or equal to 47.5183 and less than or equal to 54.8617.

[0025] In some embodiments, both the object-side and image-side surfaces of the first meniscus lens are aspherical.

[0026] In some embodiments, the side of the projection lens group facing the light source is the image side; the side of the projection lens group facing the rear projection screen is the object side; the projection lens group includes, arranged from the object side to the image side, a tenth meniscus lens with its convex surface facing the rear projection screen, an eleventh meniscus lens with its convex surface facing the rear projection screen, a twelfth biconcave lens, a thirteenth meniscus lens with its concave surface facing the rear projection screen, a fourteenth meniscus lens with its concave surface facing the rear projection screen, a fifteenth biconcave lens, a sixteenth biconvex lens, a seventeenth meniscus lens with its concave surface facing the rear projection screen, an eighteenth meniscus lens with its concave surface facing the rear projection screen, a nineteenth biconvex lens, a twentieth meniscus lens with its concave surface facing the rear projection screen, and a twenty-first biconvex lens.

[0027] In some embodiments, the curvature of the object-side surface of the tenth meniscus lens is greater than or equal to 27.6316 and less than or equal to 35.0873; the curvature of the image-side surface of the tenth meniscus lens is greater than or equal to 13.4502 and less than or equal to 13.8128; and / or

[0028] The curvature of the object-side surface of the eleventh meniscus lens is greater than or equal to 15.5080 and less than or equal to 19.1868; the curvature of the image-side surface of the eleventh meniscus lens is greater than or equal to 8.6324 and less than or equal to 8.8898; and / or

[0029] The curvature of the object-side surface of the twelfth biconcave lens is greater than or equal to 20.8448 and less than or equal to 67.6066; the curvature of the image-side surface of the twelfth biconcave lens is greater than or equal to 7.9552 and less than or equal to 8.1229; and / or

[0030] The curvature of the object-side surface of the thirteenth meniscus lens is greater than or equal to 44.5945 and less than or equal to 52.6370; the curvature of the image-side surface of the thirteenth meniscus lens is greater than or equal to 17.2742 and less than or equal to 19.2761; and / or

[0031] The curvature of the object-side surface of the fourteenth meniscus lens is greater than or equal to 51.4724 and less than or equal to 70.8826; the curvature of the image-side surface of the fourteenth meniscus lens is greater than or equal to 11.5271 and less than or equal to 11.6002; and / or

[0032] The curvature of the object-side surface of the fifteenth biconcave lens is greater than or equal to 12.2619 and less than or equal to 12.2804; the curvature of the image-side surface of the fifteenth biconcave lens is greater than or equal to 7.2067 and less than or equal to 7.2072; and / or

[0033] The curvature of the object-side surface of the sixteenth biconvex lens is greater than or equal to 7.0961 and less than or equal to 7.4158; the curvature of the image-side surface of the sixteenth biconvex lens is greater than or equal to 24.2286 and less than or equal to 28.6417; and / or

[0034] The curvature of the object-side surface of the seventeenth meniscus lens is greater than or equal to 62.4709 and less than or equal to 98.3992; the curvature of the image-side surface of the seventeenth meniscus lens is greater than or equal to 4.5543 and less than or equal to 4.6834; and / or

[0035] The curvature of the object-side surface of the eighteenth crescent lens is greater than or equal to 4.5543 and less than or equal to 4.6834; the curvature of the image-side surface of the eighteenth crescent lens is greater than or equal to 9.4348 and less than or equal to 9.4551; and / or

[0036] The curvature of the object-side surface of the nineteenth biconvex lens is greater than or equal to 51.4957 and less than or equal to 52.4758; the curvature of the image-side surface of the nineteenth biconvex lens is greater than or equal to 6.0071 and less than or equal to 6.0297; and / or

[0037] The curvature of the object-side surface of the twentieth meniscus lens is greater than or equal to 6.0071 and less than or equal to 6.0297; the curvature of the image-side surface of the twentieth meniscus lens is greater than or equal to 9.0997 and less than or equal to 9.1051; and / or

[0038] The curvature of the object side of the 21st biconvex lens is greater than or equal to 31.0497 and less than or equal to 31.1402; the curvature of the image side of the 21st biconvex lens is greater than or equal to 31.1220 and less than or equal to 31.1402.

[0039] In some embodiments, the rear projection display further includes a polarizing beam splitter disposed in the optical path between the light source and the projection lens assembly.

[0040] The present invention also proposes a vehicle including the aforementioned rear projection display.

[0041] The projection lens group receives the image light and shapes it to project the image information onto the rear projection screen. Since the concave side of the rear projection screen faces the projection lens group, the image light enters the screen from the concave side and exits from the convex side for viewing. Because the rear projection screen is curved, the image surface is also curved; understandably, the normal direction at different positions on the convex side of the curved surface is different, so the image information projected onto the rear projection screen is displayed in different directions in space due to its different position.

[0042] In this way, when information needs to be transmitted to different users in the space, it is only necessary to image the image at a specific position on the rear projection screen. Specifically, imaging the image at the position where the surface normal is directed towards the user is sufficient to accurately transmit the information to that user. It can be seen that in the process of transmitting information to users in different positions, it is not necessary to rotate the display, and since different positions on the rear projection screen can be imaged simultaneously, information can also be transmitted to different users at the same time, which significantly improves the display's response speed. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0044] Figure 1 is a structural schematic diagram of the first embodiment of the rear projection display provided by the present invention;

[0045] Figure 2 is a partial structural schematic diagram of the rear projection screen of the first embodiment of the rear projection display provided by the present invention;

[0046] Figure 3 is a first schematic diagram of the mapping relationship between the display screen and the pixels on the rear projection screen in the first embodiment of the rear projection display provided by the present invention.

[0047] Figure 4 is a second schematic diagram of the mapping relationship between the display screen and the pixels on the rear projection screen in the first embodiment of the rear projection display provided by the present invention.

[0048] Figure 5 is a schematic diagram of the structure of the second embodiment of the rear projection display provided by the present invention after removing the rear projection screen;

[0049] Figure 6 is a schematic diagram of the structure of the third embodiment of the rear projection display provided by the present invention after removing the rear projection screen;

[0050] Figure 7 is a graph showing the relationship between the modulation transfer function and the spatial frequency in the first embodiment of the rear projection display provided by the present invention.

[0051] Figure 8 is a graph showing the relationship between the modulation transfer function and the defocus amount in the first embodiment of the rear projection display provided by the present invention.

[0052] Figure 9 is a first aberration diagram of the first embodiment of the rear projection display provided by the present invention;

[0053] Figure 10 is a second aberration diagram of the first embodiment of the rear projection display provided by the present invention;

[0054] Figure 11 is a graph showing the relationship between relative illumination and field of view of the first embodiment of the rear projection display provided by the present invention;

[0055] Figure 12 is a dot diagram of the second embodiment of the rear projection display provided by the present invention;

[0056] Figure 13 is a graph showing the relationship between the modulation transfer function and the spatial frequency in the second embodiment of the rear projection display provided by the present invention.

[0057] Figure 14 is a graph showing the relationship between the modulation transfer function and the defocus amount in the second embodiment of the rear projection display provided by the present invention.

[0058] Figure 15 is a first aberration diagram of the second embodiment of the rear projection display provided by the present invention;

[0059] Figure 16 is a second aberration diagram of the second embodiment of the rear projection display provided by the present invention;

[0060] Figure 17 is a graph showing the relationship between relative illumination and field of view of the second embodiment of the rear projection display provided by the present invention;

[0061] Figure 18 is a dot diagram of the third embodiment of the rear projection display provided by the present invention;

[0062] Figure 19 is a graph showing the relationship between the modulation transfer function and the spatial frequency in the third embodiment of the rear projection display provided by the present invention.

[0063] Figure 20 is a graph showing the relationship between the modulation transfer function and the defocus amount in the third embodiment of the rear projection display provided by the present invention.

[0064] Figure 21 is a first aberration diagram of the third embodiment of the rear projection display provided by the present invention;

[0065] Figure 22 is a second aberration diagram of the third embodiment of the rear projection display provided by the present invention;

[0066] Figure 23 is a graph showing the relationship between relative illumination and field of view in the third embodiment of the rear projection display provided by the present invention;

[0067] Figure 24 is a structural schematic diagram of one embodiment of the vehicle provided by the present invention.

[0068] Explanation of icon numbers:

[0069] Vehicle 100; Passenger compartment 101; Front engine compartment hood 102; Roof 103; Rear end 104;

[0070] 10 rear projection displays;

[0071] Light source 11; Display screen 111;

[0072] Projection lens group 12; First meniscus lens 12a; Second plano-concave lens 12b; Third biconcave lens 12c; Fourth plano-convex lens 12d; Fifth meniscus lens 12e; Sixth biconcave lens 12f; Seventh biconvex lens 12g; Eighth biconvex lens 12h; Ninth meniscus lens 12i; Tenth meniscus lens 12j; Eleventh meniscus lens 12k; Twelfth biconcave lens 12m; Thirteenth meniscus lens 12n; Fourteenth meniscus lens 12p; Fifteenth biconcave lens 12q; Sixteenth biconvex lens 12r; Seventeenth meniscus lens 12s; Eighteenth meniscus lens 12t; Nineteenth biconvex lens 12u; Twentieth meniscus lens 12v; Twenty-first biconvex lens 12w;

[0073] Rear projection screen 13; Imaging surface 131; Diffusion texture 131a; Parallax surface 132; Parallax barrier grating 132a;

[0074] Polarizing beam splitter 14;

[0075] The center of the display screen is o1; the center of the rear projection screen is o2;

[0076] First meridian Lo1; Second meridian Lo2; Third meridian Lo3;

[0077] Latitude line.

[0078] The realization of the objective, functional characteristics and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0079] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0080] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0081] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of various embodiments can be combined, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0082] This invention proposes a rear projection display.

[0083] Referring to Figure 1, the rear projection display 10 proposed in this invention includes a light source 11, a projection lens group 12, and a rear projection screen 13. The light source 11 is used to generate image light carrying image information. The projection lens group 12 is disposed on the light-emitting side of the light source 11 to receive the image light. The rear projection screen 13 is curved; the rear projection screen 13 is disposed on the side of the projection lens group 12 facing away from the light source 11; the concave side of the rear projection screen 13 faces the projection lens group 12; the projection lens group 12 is used to image the image information onto the rear projection screen 13.

[0084] A rear-projection display is as opposed to a front-projection display; a front-projection display projects an image onto a screen and allows the user to view it through reflection from the screen; a rear-projection display projects an image onto a screen and allows the user to view it through transmission from the screen. Therefore, in the embodiment shown in Figure 1, the observer views the image from the side of the rear-projection screen 13 that faces away from the projection lens group 12.

[0085] The light source 11 is the optical engine used by the rear projection display to generate the initial image, and can be an LBS (Laser Beam Scanning) optical engine, etc. Therefore, the light source 11 can generate image light carrying image information.

[0086] Image light refers to the light that, after being modulated by the projection lens group 12, can project a preset image onto the rear projection screen 13. In one example, the projection lens group 12 can modulate the image light and introduce field curvature aberration, allowing the image light to be accurately focused onto the curved rear projection screen 13, presenting the final image that the observer needs to see.

[0087] The projection lens assembly 12 includes at least one lens and / or a reflector (total reflection mirror or reflector, etc.) to modulate the image light. The image light is emitted by the optical engine, passes through the projection lens assembly 12, and is then projected onto the rear projection screen 13. In the embodiment shown in FIG1, since the projection lens assembly 12 includes 9 lenses, the image light can pass through each lens of the projection lens assembly 12 sequentially to obtain modulation of the projection lens assembly 12. However, in other embodiments, other numbers of lenses can be provided, such as in the embodiments of FIG5 and FIG6, which have 12 lenses.

[0088] The rear projection screen 13 is curved, meaning that at least two of the imaging areas on the rear projection screen 13 have different normal directions. To ensure that light passing through the rear projection screen 13 can be seen by the observer, a diffusion structure is used to give the light a certain divergence angle after passing through the rear projection screen 13. The location of the diffusion structure is the "imaging area". In one example, a certain concentration of diffusing agent can be added to a layer within the substrate of the rear projection screen 13 (such as a curved plate-like structure formed of glass or special polymer materials), and the image light, after being imaged by the projection lens group 12, is focused on this layer, thus allowing the image to be seen by the observer after divergence. Of course, in other embodiments, other diffusion structures can be used, such as the diffusion texture 131a described below.

[0089] Since the rear projection screen 13 is curved, it will have a concave side and a convex side; specifically, the parts used for imaging mentioned above have a concave side and a convex side; the two places with different normal directions mentioned above should have their curvature centers on the same side of the rear projection screen 13, which is the concave side of the rear projection screen 13, and the side facing away from the concave side is the convex side of the rear projection screen 13.

[0090] With the concave side of the rear projection screen 13 facing the projection lens group 12, the image light passes through the concave side of the rear projection screen 13 and exits from the convex side. It can be seen that because there are at least two points on the rear projection screen 13 with different normal directions, it can output information in at least two directions. In one example, referring to Figure 1, the rear projection screen 13 in Figure 1 is spherical, thus possessing the ability to output information within a directional range of more than 180° on the plane shown in Figure 1.

[0091] In this way, when information needs to be transmitted to different users in the space, it is only necessary to image it at a specific position on the rear projection screen 13. Specifically, imaging at the position where the surface normal is directed towards the user is sufficient to accurately transmit information to that user. It can be seen that in the process of transmitting information to users in different positions, it is not necessary to rotate the display. Moreover, since different positions on the rear projection screen 13 can be imaged simultaneously, information can also be transmitted to different users at the same time, which significantly improves the display response speed.

[0092] Please refer to Figures 1 and 2. In some embodiments, the concave side of the rear projection screen 13 is the imaging surface 131, and the projection lens group 12 is used to image the image information onto the imaging surface 131. A diffusion texture 131a is provided on the imaging surface 131. The feature size of the diffusion texture 131a is less than or equal to 5μm, and the surface roughness of the imaging surface 131 is less than or equal to 2μm.

[0093] The aforementioned diffusion texture 131a can be formed on the imaging surface 131 using HOE (Holographic Optical Elements) technology (such as nanoimprinting or electron beam etching). The diffusion texture 131a can be a regular texture with obvious periodic characteristics; or it can be an irregular texture without periodic characteristics.

[0094] The characteristic size of the diffusion texture 131a refers to the size of the protrusions in the diffusion texture 131a along the tangent direction of the imaging surface 131, and can be the maximum size, average size, mode size, or median size of all protrusions. Since there are actually multiple tangent directions, it should be noted that when obtaining the above characteristic size, when obtaining the size of a single protrusion along the tangent direction, it can be selected in a predetermined direction (for example, the meridian direction or parallel direction mentioned below), or the maximum value in all tangent directions can be taken as the size of a protrusion. Roughness is a physical quantity that characterizes the degree of unevenness of the diffusion texture 131a as a whole on the imaging surface 131.

[0095] Image light can be focused onto the location of the diffusion texture 131a. Due to the distribution of the texture, the light passing through the texture can be directed in different directions, i.e., diffused, ultimately forming an observable image. When the feature size of the diffusion texture 131a is less than or equal to 5μm and the surface roughness is less than or equal to 2μm, the rear projection screen 13 can be made essentially transparent (measured transmittance of over 70%). Thus, when the rear projection display 10 is applied in the cockpit of vehicles such as vehicles 100, aircraft, or ships, the rear projection screen 13 will not obstruct the driver's view when it is not in operation. In addition, it can also ensure a reasonable diffusion angle for light (measured diffusion angle less than 25°), so that the diffusion angle is not too large and weakens the display brightness at the viewing angle.

[0096] In one example, the feature size of the diffusion texture 131a can be one of 3.5μm, 3.6μm, 3.7μm, 3.8μm, 3.9μm, 4.0μm, 4.1μm, 4.2μm, 4.3μm, 4.4μm, 4.5μm, 4.6μm, 4.7μm, 4.8μm, 4.9μm, and 5.0μm; while the surface roughness of the imaging surface 131 can be one of 1.0μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, 1.9μm, and 2.0μm.

[0097] Please refer to Figures 1 and 2. In some embodiments, the convex side of the rear projection screen 13 is a parallax surface 132; a parallax barrier grating 132a is provided on the parallax surface 132.

[0098] Since the convex and concave sides of the rear projection screen 13 are naturally separated, after forming a diffusion texture 131a that can form pixels on the concave side, a parallax barrier grating 132a is formed on the convex side. In conjunction with the diffusion texture 131a, a three-dimensional image display can be formed, reducing the hardware cost of three-dimensional display.

[0099] Please refer to Figure 2. In the schematic structure of the parallax barrier grating 132a in the figure, the protruding part is the light-blocking part, and the rest is the light-transmitting part. It can be seen that the parallax barrier grating 132a is spaced apart from the imaging surface 131. In this way, after the parallax barrier grating 132a blocks the light, the observer's left and right eyes can see different parts on the imaging surface 131, so that the user's left and right eyes can form images separately, thereby forming a three-dimensional display.

[0100] It should be noted that Figure 2 is only a schematic diagram, and the light-shielding structure of the protruding part can take many forms, and therefore does not necessarily protrude from the surface of the parallax surface 132. In one example, the light-shielding structure can be a metal film or a light-shielding adhesive, etc. Even liquid crystal elements or electrochromic elements can be used to realize a controllable parallax barrier grating 132a. In Figure 2, for ease of illustration, the diffusion texture 131a and the parallax barrier grating 132a are not drawn to scale; generally, the feature size of the diffusion texture 131a is much smaller than the spatial period of the parallax barrier grating 132a.

[0101] It should also be noted that other protective layers may be covered on the parallax barrier grating 132a or the imaging surface 131 in order to protect them. In this case, the parallax surface 132 and the imaging surface 131 can be considered as not being the surfaces of the rear projection screen 13, but rather that the parallax surface 132 is on the side of the rear projection surface that faces away from the projection lens group 12.

[0102] It should also be noted that the rear projection display 10 can not only be used for information transmission, but also serve a decorative purpose. In particular, when the rear projection display 10 can display three-dimensional images, it can form an "electronic crystal ball" with adjustable patterns, which is highly ornamental. Such a decorative scheme makes it convenient to adjust the displayed content.

[0103] Please refer to Figure 1. In some embodiments, the rear projection screen 13 is spherical, ellipsoidal, or cylindrical.

[0104] The normal directions at each point on the surface of a sphere, ellipsoid, and cylinder are different, resulting in an extremely rich variety of light emission directions. This can increase the directions in which the rear projection display 10 transmits information, making it easier to transmit information to more observers.

[0105] It should be noted that the rear projection screen 13 does not need to be a complete sphere, a complete ellipsoid, or a complete cylinder. In the embodiment shown in Figure 1, the rear projection screen 13 is partially spherical, that is, it is provided with an opening for part of the projection lens assembly 12 to enter.

[0106] In some embodiments, the projection lens group 12 and the light source 11 (which may also include the polarizing beam splitter 14 mentioned below) are both located within the rear projection screen 13, in which case the rear projection screen 13 can be substantially spherical or ellipsoidal in shape. However, it should be noted that, for this embodiment, the description of the relative positional relationship between the rear projection screen 13, the projection lens group 12, and the light source 11 above should be understood as the relative positional relationship on the optical path of image light propagation; the relative positional relationship of the imaging surface 131, the parallax surface 132, the diffusion texture 131a, and the parallax barrier grating 132a should also be understood as the positional relationship on the optical path of image light propagation.

[0107] Please refer to Figures 1, 3, and 4. In some embodiments, the light source 11 is a display screen 111, and the position of the optical axis passing through the projection lens group 12 on the display screen 111 is the center o1 of the display screen. The projection lens group 12 is used to project a straight line passing through the center o1 of the display screen 111 onto a meridian of the rear projection screen 13. The meridian of the rear projection screen 13 intersects at the position of the optical axis passing through the projection lens group 12 on the rear projection screen 13.

[0108] The display screen 111 can be a DMD (Digital Micromirror Device) optical engine, an LCD (Liquid Crystal Display) optical engine, or an LCoS (Liquid Crystal on Silicon) optical engine, etc., and is an optical engine with an actual display surface (LBS optical engines often only have a virtual display surface).

[0109] The center o1 of the display screen is the position of the optical axis of the projection lens group 12 on the display surface of the display screen 111; the center o2 of the rear projection screen can also be considered as the position of the rear projection screen 13 through the optical axis of the projection lens group 12. When the projection lens group 12 is a pure lens group 12 without reflecting elements, as shown in Figure 1, it can be seen from the direction from the rear projection screen 13 to the display screen 111, parallel to the optical axis of the projection lens group 12, that is, from a top-down view, the center o1 of the display screen coincides with the center o2 of the rear projection screen; Figure 3 (1) reflects this relationship, that is, after removing the projection lens group 12, the center o1 of the display screen can be seen from the top-down view of the rear projection screen 13. In addition, please note Figure 3 (2), which can be considered as the left view of the rear projection screen 13 in (1), and you can see the correspondence between the first meridian Lo1, the second meridian Lo2 and the third meridian Lo3 in (1) and (2).

[0110] In the embodiment of the projection lens group 12 including the reflective element, the optical axes of the elements before and after the reflective element can be aligned to coincide with each other, and the above phenomenon can also be observed. In this case, the reflective element can be ignored.

[0111] As can be seen in the above embodiments, the orthographic projection of the meridians on the rear projection screen 13 onto the display screen 111 is a number of straight lines intersecting the center o1 of the display screen; and the orthographic projection of the parallels La on the rear projection screen 13 onto the display screen 111 is a concentric circle centered on the center o1 of the display screen.

[0112] This allows for a simple mapping relationship between the pixels on the display screen 111 and the pixels on the rear projection screen 13. Referring to Figure 4, it can be seen that this allows the dimensions on the rear projection screen 13 to have a basically linear relationship with the planar coordinates on the display screen 111. This simple relationship simplifies the design of the projection lens assembly 12 and reduces the design cost of the rear projection display 10.

[0113] The mapping relationship described above can be determined by tracing the light paths of the pixels on the display screen 111. For example, a pixel on a straight line passing through the center o1 of the display screen 111 can be lit up, and the illuminated position on the rear projection screen 13 can be marked. It can then be observed whether a meridian on the rear projection screen 13 is illuminated. If multiple pixels on straight lines passing through the center of the display screen 111 are lit up in sequence, and multiple meridians on the rear projection screen 13 are observed to be lit up in sequence, then the mapping relationship described above can be considered to be used.

[0114] It should be noted that this simple correspondence is also very beneficial for generating three-dimensional images, because the display of three-dimensional images requires a close match between the pixels on the imaging surface 131 and the parallax barrier grating 132a. Maintaining a simple mapping between the pixels on the display screen 111 and the pixels on the rear projection screen 13 is beneficial for maintaining the accurate match between the pixels on the imaging surface 131 and the parallax barrier grating 132a, thereby improving the imaging effect of the three-dimensional display.

[0115] Please refer to Figure 1. In some embodiments, the focal length of the projection lens group 12 is greater than or equal to 1.4 mm and less than or equal to 5 mm.

[0116] The focal length of the projection lens group 12 can be EFL (Effective Focal Length). The smaller the focal length of the projection lens group 12, the stronger its ability to refract light, and the more likely it is to cause aberrations such as chromatic aberration, thus reducing image quality; the larger the focal length of the projection lens group 12, the greater the required focusing distance, making the size of the rear projection display 10 too large.

[0117] When the focal length of the projection lens group 12 is greater than or equal to 1.4 mm and less than or equal to 5 mm, the rear projection display 10 can have high imaging quality and a small size. Please refer to Figures 9, 10, 15, 16, 21, and 22, which illustrate the aberrations of the first, second, and third embodiments of the rear projection display 10 in this application. The left images in Figures 9, 15, and 21 show field curvature distortion; the right images show scanning distortion (F-theta distortion). Figures 10, 16, and 22 show transverse chromatic aberration. It can be seen that both field curvature distortion and scanning distortion are small, and the transverse chromatic aberration is basically controlled within the diffraction limit, resulting in high imaging performance.

[0118] In one example, the focal length of the projection lens group 12 can be any of 1.4mm, 1.6mm, 1.8mm, 2.0mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3.0mm, 3.2mm, 3.6mm, 3.8mm, 4.0mm, 4.2mm, 4.6mm, 4.8mm, and 5.0mm.

[0119] Please refer to Figure 1. In some embodiments, the display angle of the rear projection screen 13 is greater than or equal to 180° and less than or equal to 240°.

[0120] The display angle can be the field of view of the rear projection display 10 in a certain direction, such as a horizontal field of view, a vertical field of view, or a diagonal field of view; or it can be considered as the average of the field of view in various directions.

[0121] When the display angle is too small, it may be difficult to meet the needs of conveying information to users in multiple directions. When the display angle is too large, it may cause serious aberrations in the display, resulting in a degraded display effect. However, when the display angle of the rear projection screen 13 is greater than or equal to 180° and less than or equal to 240°, it can provide a sufficient display angle to convey information to users in all directions and also have a sufficient display effect.

[0122] The embodiment shown in Figure 1 has a diagonal field of view of 240°. In addition to Figures 9 and 10, Figures 7, 8 and 11 can also be referred to. In Figure 7, it can be seen that when transmitting information with different spatial frequencies (i.e., the horizontal axis is Spatial Frequency in cycles per mm, which is the spatial frequency in units of cycles per millimeter), the modulation transfer function (i.e., the vertical axis is the Modulus of the Optical Transfer Function, which is the spatial frequency in units of cycles per millimeter) changes. Multiple curves represent data at different field of view angles. It can be seen that within a sufficient field of view, information with higher spatial frequencies can be transmitted with a lower distortion rate.

[0123] Figure 8 illustrates the relationship between the defocus amount (the horizontal axis represents the focus shift in millimeters) and the modulation transfer function (the vertical axis represents the modulus of the optical transfer function), with multiple curves showing data at different field of view angles. It is evident that within a sufficient field of view, higher spatial frequency information can be transmitted with relatively low distortion, and the distortion rate does not decrease rapidly with increasing defocus amount.

[0124] Figure 11 shows the relationship between the field of view (horizontal axis) and relative illumination (vertical axis). It can be seen that even when the field of view reaches 120°, the relative illumination does not decrease significantly, maintaining uniform relative illumination across the entire field of view.

[0125] In one example, the display angle of the rear projection screen 13 can be one of 180°, 185°, 190°, 195°, 200°, 205°, 210°, 215°, 220°, 225°, 230°, 235° and 240°.

[0126] Please refer to Figure 1. In some embodiments, the diameter of the rear projection screen 13 is greater than or equal to 80 mm and less than or equal to 130 mm.

[0127] The diameter of the rear projection screen 13 refers to the maximum distance between two points on the rear projection screen 13. When the diameter of the rear projection screen 13 is too small, the display area is insufficient, and the information content that can be transmitted is limited; when the diameter of the rear projection screen 13 is too large, it is not conducive to miniaturization and is difficult to apply in the passenger compartment 101 of vehicles such as vehicle 100. However, when the diameter of the rear projection screen 13 is greater than or equal to 80mm and less than or equal to 130mm, it can have a sufficient display area and can be miniaturized.

[0128] In one example, the diameter of the rear projection screen 13 can be one of 80mm, 85mm, 90mm, 95mm, 100mm, 105mm, 110mm, 115mm, 120mm, 125mm and 130mm.

[0129] Please refer to Figure 1. In some embodiments, the total optical length of the projection lens group 12 is greater than or equal to 40 mm and less than or equal to 70 mm.

[0130] The total optical length of the projection lens group 12 refers to the distance from the farthest point of the projection lens group 12 facing away from the light source 11 to the light source 11 along the optical axis of the projection lens group 12. In one example, referring to Figure 1, the total optical length of the projection lens group 12 is the distance from the vertex of the object-side surface of the first meniscus lens 12a to the display screen 111.

[0131] When the total optical length of the projection lens group 12 is too large, it hinders the miniaturization of the rear projection display 10. When the total optical length of the projection lens group 12 is too small, it requires an excessively high beam shaping capability, greatly increasing the design complexity. However, when the total optical length of the projection lens group 12 is greater than or equal to 40mm and less than or equal to 70mm, the design of the projection lens group 12 is easier and it can be miniaturized sufficiently.

[0132] In one example, the total optical length of the projection lens group 12 can be one of 40mm, 43mm, 46mm, 49mm, 50mm, 53mm, 56mm, 59mm, 60mm, 63mm, 66mm, 69mm, and 70mm.

[0133] Please refer to Figure 1. In some embodiments, the MTF70 of the rear projection display 10 is greater than or equal to 50%, or the MTF110 is greater than or equal to 30%.

[0134] MTF70 refers to the modulation transfer function when transmitting information at a spatial frequency of 70 cycles / mm; MTF110 refers to the modulation transfer function when transmitting information at a spatial frequency of 110 cycles / mm.

[0135] Information with a spatial frequency of 70 cycles / mm accounts for a large proportion of general image information; information with a spatial frequency of 110 cycles / mm accounts for a smaller proportion of general image information. Therefore, an MTF of 70 greater than or equal to 50% ensures sufficient clarity for displaying general images, while an MTF of 110 greater than or equal to 30% ensures sufficient redundancy for the display's maximum performance. The rear projection display 10 has an MTF of 70 greater than or equal to 50% and an MTF of 110 greater than or equal to 30%, enabling it to meet the needs well in most application scenarios.

[0136] It should be noted that both MTF70 and MTF110 can be measured at different field of view angles. Please refer to Figures 7, 13, and 19, where the MTF70 and MTF110 at different field of view angles are shown in the three embodiments of the rear projection display 10 in the accompanying drawings. The numerical ranges for MTF70 and MTF110 mentioned above refer to the average values ​​across the entire field of view. It is evident that the MTF70 and MTF110 in the three embodiments shown in Figures 1, 5, and 6 of this application all satisfy the aforementioned ranges.

[0137] Please refer to Figures 1, 5 and 6. In some embodiments, the number of lenses with optical power in the projection lens group 12 is 9, 10, 11 or 12.

[0138] If the number of lenses is too small, each lens will bear a greater shaping burden, which can easily lead to aberrations. On the other hand, if the number of lenses is too large, the design freedom will increase, but the design difficulty will also increase. However, the correction effect will not be improved accordingly due to marginal effects. Therefore, when the number of lenses with optical power in the projection lens group 12 is 9, 10, 11 or 12, it can have lower design difficulty and smaller aberrations.

[0139] Referring to Figure 1, in some embodiments, the side of the projection lens group 12 facing the light source 11 is the image side; the side of the projection lens group 12 facing the rear projection screen 13 is the object side; the projection lens group 12 includes a first meniscus lens 12a with its convex surface facing the rear projection screen 13, a second plano-concave lens 12b with its plane facing the rear projection screen 13, a third biconcave lens 12c, a fourth plano-convex lens 12d with its plane facing the rear projection screen 13, a fifth meniscus lens 12e with its concave surface facing the rear projection screen 13, a sixth biconcave lens 12f, a seventh biconvex lens 12g, an eighth biconvex lens 12h, and a ninth meniscus lens 12i with its convex surface facing the rear projection screen 13, arranged from the object side to the image side.

[0140] It should be noted that, in the art, the side of the projection lens group 12 facing the light source 11 may also be defined as the object side, and the side facing the rear projection screen 13 as the image side. However, in this application, the side of the projection lens group 12 facing the light source 11 is uniformly considered as the image side, and the side facing the rear projection screen 13 is considered as the object side. Including in Figures 7 to 23, the meanings of image and object are also consistent with the above definitions. For example, in Figure 18, the object surface is the imaging surface 131 on the rear projection screen 13, and the image surface is the light-emitting surface on the display screen 111.

[0141] In applications where image light is focused onto a curved rear projection screen 13, additional requirements are placed on the projection lens assembly 12. Specifically, it must artificially introduce field curvature aberration to fit the curved rear projection screen 13, while simultaneously eliminating other aberrations to ensure image quality. Therefore, the projection lens assembly 12 needs to maintain a certain degree of symmetry, but not perfect symmetry. When the projection lens assembly 12 has nine lenses, and these lenses are selected according to the aforementioned lens surface types, these requirements are perfectly met.

[0142] Please refer to Figures 7 to 11. As can be seen, the lenses arranged according to the above surface shape can have a better display effect and fit into the spherical rear projection screen 13.

[0143] Referring to Figure 1, in some embodiments, the curvature of the object-side surface of the first meniscus lens 12a is greater than or equal to 18.3139 and less than or equal to 18.3443; the curvature of the image-side surface of the first meniscus lens 12a is greater than or equal to 13.7802 and less than or equal to 13.8072; and / or

[0144] The curvature of the image-side surface of the second plano-concave lens 12b is greater than or equal to 7.3390 and less than or equal to 8.2117; and / or

[0145] The curvature of the object-side surface of the third biconcave lens 12c is greater than or equal to 8.3677 and less than or equal to 8.8656; the curvature of the image-side surface of the third biconcave lens 12c is greater than or equal to 22.1583 and less than or equal to 25.2139; and / or

[0146] The curvature of the image-side surface of the fourth plano-convex lens 12d is greater than or equal to 9.1273 and less than or equal to 10.6210; and / or

[0147] The curvature of the object-side surface of the fifth meniscus lens 12e is greater than or equal to 17.6516 and less than or equal to 20.1569; the curvature of the image-side surface of the fifth meniscus lens 12e is greater than or equal to 33.2025 and less than or equal to 35.2493; and / or

[0148] The curvature of the object-side surface of the sixth biconcave lens 12f is greater than or equal to 10.3510 and less than or equal to 11.393; the curvature of the image-side surface of the sixth biconcave lens 12f is greater than or equal to 46.7441 and less than or equal to 86.8944; and / or

[0149] The curvature of the object-side surface of the seventh biconvex lens 12g is greater than or equal to 46.7441 and less than or equal to 86.8944; the curvature of the image-side surface of the seventh biconvex lens 12g is greater than or equal to 9.9202 and less than or equal to 11.0307; and / or

[0150] The curvature of the object-side surface of the eighth biconvex lens 12h is greater than or equal to 76.3248 and less than or equal to 258.8315; the curvature of the image-side surface of the eighth biconvex lens 12h is greater than or equal to 20.0161 and less than or equal to 22.7941; and / or

[0151] The curvature of the object side of the ninth meniscus lens 12i is greater than or equal to 14.1233 and less than or equal to 15.5154; the curvature of the image side of the ninth meniscus lens 12i is greater than or equal to 47.5183 and less than or equal to 54.8617.

[0152] In the first embodiment of the rear projection display 10 in this application, the selection of each lens can be as shown in Tables 1 and 2 below.

[0153] Table 1:

[0154]

[0155] Table 2 shows the possible selections of aspheric coefficients for the two aspheric surface types in Table 1.

[0156] Table 2:

[0157]

[0158] In the first embodiment of the rear projection display 10, the selection of each lens can also be as shown in Tables 3 and 4 below.

[0159] Table 3:

[0160]

[0161] Table 4 shows the possible selections of aspheric coefficients for the two aspheric surface types in Table 3.

[0162] Table 4:

[0163]

[0164] The structural designs in Tables 1 and 2, as well as Tables 3 and 4, can all achieve the performance specifications shown in Table 5.

[0165] Table 5:

[0166]

[0167] In Tables 1 and 3, please note that the order of the lenses is from the object side to the image side, and the surface types also appear in this order.

[0168] In addition to the performance specifications mentioned above, Figures 7 to 11 also show the performance specifications that can be achieved by the two selection methods mentioned above.

[0169] It should be noted that in Tables 1, 3, 6, and 7 of this application, the units for thickness and radius of curvature are all mm. Thickness refers to the distance between the front and rear surfaces on the optical axis. For example, in Table 1, the thickness of S2 is 2 mm, which refers to the distance between S2 and S3 on the optical axis; the thickness of S3 is 11.3 mm, which refers to the distance between S3 and S4 on the optical axis. In Tables 1, 3, 6, and 7, Nd refers to the refractive index and has no unit; Vd refers to the Abbe number and also has no unit.

[0170] As can be seen, with the curvature selected above, clear imaging over a large field of view can be achieved on the curved rear projection screen 13, ensuring a sufficient range of light emission angles and clear imaging. Therefore, within the curvature range mentioned above, better imaging effects and display angles can be obtained.

[0171] It should be noted that: the first meniscus lens 12a, with negative optical power, can produce a light refraction angle exceeding 240°; the second plano-concave lens 12b, with negative optical power, can refract and control the light entering the aperture; the third biconcave lens 12c, with negative optical power, can refract and control the light entering the aperture; the fourth plano-convex lens 12d, with positive optical power, can refract and control the light entering the aperture; the fifth meniscus lens 12e, with positive optical power, can refract and control the light entering the aperture; and the sixth biconcave lens 12f, with negative optical power, can refract and control the field of view. An angle is used to refract light into the image plane; a seventh biconvex lens 12g with positive optical power can refract and control the field angle of light, causing light to refract into the image plane; an eighth biconvex lens 12h with positive optical power can refract and control the field angle of light, causing light to refract into the image plane; a ninth meniscus lens 12i with negative optical power can refract and control the field angle of light, causing light to refract into the image plane; and a polarizing beam splitter 14 (which can be a PBS prism) with polarizing beam splitting function can transmit P light and reflect S light, and the rear projection display 10 can use the separated P light to form an image.

[0172] Referring to Figure 1, in some embodiments, both the object-side and image-side surfaces of the first meniscus lens 12a are aspherical. This allows the first meniscus lens 12a to have a larger light refraction angle while better suppressing aberrations.

[0173] Please refer to Figures 5 and 6. In some embodiments, the side of the projection lens group 12 facing the light source 11 is the image side; the side of the projection lens group 12 facing the rear projection screen 13 is the object side. The projection lens group 12 includes, arranged from the object side to the image side, a tenth meniscus lens 12j with its convex surface facing the rear projection screen 13, an eleventh meniscus lens 12k with its convex surface facing the rear projection screen 13, a twelfth biconcave lens 12m, a thirteenth meniscus lens 12n with its concave surface facing the rear projection screen 13, a fourteenth meniscus lens 12p with its concave surface facing the rear projection screen 13, a fifteenth biconcave lens 12q, a sixteenth biconvex lens 12r, a seventeenth meniscus lens 12s with its concave surface facing the rear projection screen 13, an eighteenth meniscus lens 12t with its concave surface facing the rear projection screen 13, a nineteenth biconvex lens 12u, a twentieth meniscus lens 12v with its concave surface facing the rear projection screen 13, and a twenty-first biconvex lens 12w.

[0174] In applications where image light is focused onto a curved rear projection screen 13, additional requirements are placed on the projection lens assembly 12. Specifically, it must artificially introduce field curvature aberration to fit the curved rear projection screen 13, while simultaneously eliminating other aberrations to ensure image quality. Therefore, the projection lens assembly 12 needs to maintain a certain degree of symmetry, but not perfect symmetry. When the projection lens assembly 12 has twelve lenses, selected according to the aforementioned lens surface types, it perfectly meets these requirements.

[0175] Please refer to Figures 12 to 23. As can be seen, the lenses arranged according to the above surface shape can have a better display effect and fit into the spherical rear projection screen 13.

[0176] In Figures 12 to 23, Figures 12 and 18 are dot plots of the second embodiment (the embodiment shown in Figure 5) and the third embodiment (the embodiment shown in Figure 6) of the rear projection display 10, respectively. It can be seen that the blur spot is small and the imaging quality is high at different viewing angles.

[0177] Figures 13 and 19 show the modulation transfer functions (i.e., the vertical axis, OTF magnitude, where OTF stands for Optical Transfer Function) of the second embodiment (the embodiment shown in Figure 5) and the third embodiment (the embodiment shown in Figure 6) of the rear projection display 10 when transmitting information at different spatial frequencies. It can be seen that the modulation transfer function is relatively high at different viewing angles, ensuring that image information in the image light is imaged onto the rear projection screen 13 with minimal loss.

[0178] Figures 14 and 20 are curves showing the modulation transfer function as a function of defocusing in the second embodiment (the embodiment shown in Figure 5) and the third embodiment (the embodiment shown in Figure 6) of the rear projection display 10, respectively. It can be seen that even with slight defocusing, there can be a high efficiency in image information transmission (i.e., the vertical axis value is large, where the vertical axis is the square wave MTF, and MTF is the modulation transfer function).

[0179] Figures 15 and 21 are aberration diagrams of the second embodiment (the embodiment shown in Figure 5) and the third embodiment (the embodiment shown in Figure 6) of the rear projection display 10, respectively. The left image in each figure shows field curvature aberration, and the right image shows scanning distortion (F-theta distortion). It can be seen that both field curvature aberration and scanning distortion are relatively weak.

[0180] Figures 16 and 22 are the lateral chromatic aberration diagrams of the second embodiment (the embodiment shown in Figure 5) and the third embodiment (the embodiment shown in Figure 6) of the rear projection display 10, respectively. The lateral chromatic aberration is basically controlled within the diffraction limit (i.e., between the dashed lines in the figure, where the dashed lines represent the range represented by the Airy disk; the Airy symbol in Figure 10 indicates the straight line represented by the Airy disk).

[0181] Figures 17 and 23 show the relationship between the field of view and relative illuminance of the second embodiment (the embodiment shown in Figure 5) and the third embodiment (the embodiment shown in Figure 6) of the rear projection display 10, respectively. It can be seen that the relative illuminance is relatively consistent throughout the entire field of view, so the display brightness is relatively uniform.

[0182] Referring to Figures 5 and 6, in some embodiments, the curvature of the object-side surface of the tenth meniscus lens 12j is greater than or equal to 27.6316 and less than or equal to 35.0873; the curvature of the image-side surface of the tenth meniscus lens 12j is greater than or equal to 13.4502 and less than or equal to 13.8128; and / or

[0183] The curvature of the object side of the eleventh meniscus lens 12k is greater than or equal to 15.5080 and less than or equal to 19.1868; the curvature of the image side of the eleventh meniscus lens 12k is greater than or equal to 8.6324 and less than or equal to 8.8898; and / or

[0184] The curvature of the object-side surface of the 12th biconcave lens 12m is greater than or equal to 20.8448 and less than or equal to 67.6066; the curvature of the image-side surface of the 12th biconcave lens 12m is greater than or equal to 7.9552 and less than or equal to 8.1229; and / or

[0185] The curvature of the object side of the thirteenth meniscus lens 12n is greater than or equal to 44.5945 and less than or equal to 52.6370; the curvature of the image side of the thirteenth meniscus lens 12n is greater than or equal to 17.2742 and less than or equal to 19.2761; and / or

[0186] The curvature of the object-side surface of the fourteenth meniscus lens 12p is greater than or equal to 51.4724 and less than or equal to 70.8826; the curvature of the image-side surface of the fourteenth meniscus lens 12p is greater than or equal to 11.5271 and less than or equal to 11.6002; and / or

[0187] The curvature of the object-side surface of the fifteenth biconcave lens 12q is greater than or equal to 12.2619 and less than or equal to 12.2804; the curvature of the image-side surface of the fifteenth biconcave lens 12q is greater than or equal to 7.2067 and less than or equal to 7.2072; and / or

[0188] The curvature of the object-side surface of the sixteenth biconvex lens 12r is greater than or equal to 7.0961 and less than or equal to 7.4158; the curvature of the image-side surface of the sixteenth biconvex lens 12r is greater than or equal to 24.2286 and less than or equal to 28.6417; and / or

[0189] The curvature of the object-side surface of the 17th meniscus lens 12s is greater than or equal to 62.4709 and less than or equal to 98.3992; the curvature of the image-side surface of the 17th meniscus lens 12s is greater than or equal to 4.5543 and less than or equal to 4.6834; and / or

[0190] The curvature of the object-side surface of the eighteenth-curve moon lens 12t is greater than or equal to 4.5543 and less than or equal to 4.6834; the curvature of the image-side surface of the eighteenth-curve moon lens 12t is greater than or equal to 9.4348 and less than or equal to 9.4551; and / or

[0191] The curvature of the object-side surface of the nineteenth biconvex lens 12u is greater than or equal to 51.4957 and less than or equal to 52.4758; the curvature of the image-side surface of the nineteenth biconvex lens 12u is greater than or equal to 6.0071 and less than or equal to 6.0297; and / or

[0192] The curvature of the object-side surface of the 20th meniscus lens 12v is greater than or equal to 6.0071 and less than or equal to 6.0297; the curvature of the image-side surface of the 20th meniscus lens 12v is greater than or equal to 9.0997 and less than or equal to 9.1051; and / or

[0193] The curvature of the object side of the 21st biconvex lens 12w is greater than or equal to 31.0497 and less than or equal to 31.1402; the curvature of the image side of the 21st biconvex lens 12w is greater than or equal to 31.1220 and less than or equal to 31.1402.

[0194] The surface shape of the lens of the projection lens group 12 in the second embodiment of the rear projection display 10 can be selected as shown in Table 6 below.

[0195] Table 6:

[0196]

[0197] The surface shape of the lens of the projection lens group 12 in the third embodiment of the rear projection display 10 can be selected as shown in Table 7 below.

[0198] Table 7:

[0199]

[0200] In Tables 6 and 7, please note that the lenses are arranged in order from the object side to the image side, and the surface types also appear in this order.

[0201] In addition to the performance specifications described above, Figures 12 to 17 show the performance specifications achievable by the second embodiment of the rear projection display 10; Figures 18 to 23 show the performance specifications achievable by the third embodiment of the rear projection display 10.

[0202] As can be seen, with the curvature selected above, clear imaging over a large field of view can be achieved on the curved rear projection screen 13, ensuring a sufficient range of light emission angles and clear imaging. Therefore, within the curvature range mentioned above, better imaging effects and display angles can be obtained.

[0203] Please refer to Figures 1, 5 and 6. In some embodiments, the rear projection display 10 further includes a polarizing beam splitter 14, which is disposed in the optical path between the light source 11 and the projection lens group 12.

[0204] The polarization beam splitter 14 can split the incident light into two linearly polarized beams with mutually orthogonal polarization directions. Therefore, the image light can be formed as linearly polarized light after it is incident on the polarization beam splitter 14.

[0205] The polarization beam splitter 14 can be used in conjunction with the display screen 111. For example, when the display screen 111 is an LCoS type optical engine, the polarization beam splitter 14 can be used in conjunction with the LCoS chip to perform final modulation on the emitted light of the LCoS chip, so as to optimize the polarization light utilization and improve the modulation contrast.

[0206] The polarizing beam splitter 14 can also be used in conjunction with the rear projection screen 13. In one example, the parallax barrier grating 132a disposed on the parallax surface 132 of the rear projection screen 13 has polarization properties, that is, the transparent part and the opaque part are structures that allow P-light to pass through and S-light to pass through, respectively. If the incident light is P-light or S-light, one of the structures that allow P-light to pass through and the structure that allows S-light to pass through can be allowed to pass through, while the other can be blocked, forming the parallax barrier grating 132a. At this time, the projection lens group 12 can choose a structure with fewer lenses to avoid the loss of polarization degree when the polarized light passes through the lenses.

[0207] Please refer to Figure 24. The present invention also proposes a vehicle 100, which includes the rear projection display 10 described above. The specific structure of the rear projection display 10 is as described in the above embodiments. Since the vehicle 100 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0208] The rear projection display 10 can be installed inside the vehicle, i.e., inside the passenger compartment 101, specifically on the center console, for transmitting information to the driver and other passengers; it can also be installed on the roof 103 for transmitting information to rear passengers. The rear projection display 10 can also be installed outside the vehicle to transmit information to other road users, specifically on the hood 102, the roof 103, and / or the rear 104.

[0209] It should be noted that the vehicle 100 shown in Figure 24 is a sedan, but the rear projection display 10 can also be applied to other types of vehicles 100 such as SUVs, pickup trucks and vans.

[0210] The above description is merely an exemplary embodiment of the present invention and does not limit the scope of protection of the present invention. Any equivalent structural transformations made based on the technical concept of the present invention and the contents of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. A rear projection display, characterized in that, include: A light source is used to generate image light that carries image information; A projection lens assembly is disposed on the light-emitting side of the light source to receive the image light; The rear projection screen is curved. The rear projection screen is disposed on the side of the projection lens group that faces away from the light source; the concave side of the rear projection screen faces the projection lens group; the projection lens group is used to image the image information onto the rear projection screen; the side of the projection lens group facing the light source is the image side; The side of the projection lens assembly facing the rear projection screen is the object side; the projection lens assembly includes, arranged from the object side to the image side: a first meniscus lens with a convex surface facing the rear projection screen and having negative optical power; a second plano-concave lens with a flat surface facing the rear projection screen and having negative optical power; a third biconcave lens with negative optical power; a fourth plano-convex lens with a flat surface facing the rear projection screen and having positive optical power; a fifth meniscus lens with a concave surface facing the rear projection screen and having positive optical power; a sixth biconcave lens with negative optical power; a seventh biconvex lens with positive optical power; and an eighth biconvex lens with positive optical power. The rear projection screen has a ninth meniscus lens with a convex surface facing the rear projection screen and having negative optical power; the focal length of the projection lens group is greater than or equal to 1.4 mm and less than or equal to 5 mm; the display angle of the rear projection screen is greater than or equal to 180° and less than or equal to 240°; the diameter of the rear projection screen is greater than or equal to 80 mm and less than or equal to 130 mm; the total optical length of the projection lens group is greater than or equal to 40 mm and less than or equal to 70 mm; and the MTF70 of the rear projection display is greater than or equal to 50%, or the MTF110 is greater than or equal to 30%.

2. The rear projection display as described in claim 1, characterized in that, The concave side of the rear projection screen is the imaging surface, and the projection lens group is used to image the image information onto the imaging surface; the imaging surface is provided with a diffusion texture, the feature size of the diffusion texture is less than or equal to 5μm, and the surface roughness of the imaging surface is less than or equal to 2μm.

3. The rear projection display as described in claim 2, characterized in that, The convex side of the rear projection screen is a parallax surface; a parallax barrier grating is provided on the parallax surface.

4. The rear projection display as described in claim 1, characterized in that, The rear projection screen is spherical, ellipsoidal, or cylindrical.

5. The rear projection display as described in claim 4, characterized in that, The light source is a display screen, and the position of the optical axis passing through the projection lens group on the display screen is the center of the display screen; the projection lens group is used to project a straight line passing through the center of the display screen onto a meridian of the rear projection screen. The meridians of the rear projection screen intersect at the position where the optical axis of the rear projection screen passes through the projection lens group.

6. The rear projection display as described in any one of claims 1 to 5, characterized in that, The curvature of the object-side surface of the first meniscus lens is greater than or equal to 18.3139 and less than or equal to 18.3443; the curvature of the image-side surface of the first meniscus lens is greater than or equal to 13.7802 and less than or equal to 13.8072; and / or the curvature of the image-side surface of the second plano-concave lens is greater than or equal to 7.3390 and less than or equal to 8.2117; and / or the curvature of the object-side surface of the third biconcave lens is greater than or equal to 8.3677 and less than or equal to 8.8656; The curvature of the image-side surface of the third biconcave lens is greater than or equal to 22.1583 and less than or equal to 25.2139; and / or the curvature of the image-side surface of the fourth plano-convex lens is greater than or equal to 9.1273 and less than or equal to 10.6210; and / or the curvature of the object-side surface of the fifth meniscus lens is greater than or equal to 17.6516 and less than or equal to 20.1569; the curvature of the image-side surface of the fifth meniscus lens is greater than or equal to 33.2025 and less than or equal to 35.2493; and / or Or the curvature of the object-side surface of the sixth biconcave lens is greater than or equal to 10.3510 and less than or equal to 11.393; the curvature of the image-side surface of the sixth biconcave lens is greater than or equal to 46.7441 and less than or equal to 86.8944; and / or the curvature of the object-side surface of the seventh biconvex lens is greater than or equal to 46.7441 and less than or equal to 86.8944; the curvature of the image-side surface of the seventh biconvex lens is greater than or equal to 9.9202 and less than or equal to 11.0307; and / or Alternatively, the curvature of the object-side surface of the eighth biconvex lens is greater than or equal to 76.3248 and less than or equal to 258.8315; the curvature of the image-side surface of the eighth biconvex lens is greater than or equal to 20.0161 and less than or equal to 22.7941; and / or the curvature of the object-side surface of the ninth meniscus lens is greater than or equal to 14.1233 and less than or equal to 15.5154; the curvature of the image-side surface of the ninth meniscus lens is greater than or equal to 47.5183 and less than or equal to 54.8617.

7. The rear projection display as described in any one of claims 1 to 5, characterized in that, Both the object-side and image-side surfaces of the first meniscus lens are aspherical.

8. The rear projection display as described in any one of claims 1 to 5, characterized in that, The rear projection display also includes a polarizing beam splitter, which is disposed in the optical path between the light source and the projection lens group.

9. A vehicle, characterized in that, Including the rear projection display as described in any one of claims 1-8.

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