Vehicle light projection apparatus

Abstract

A vehicle light projection apparatus, comprising: a light source (310); an illumination lens group (320) located at a light output side of the light source (310); the illumination lens group (320) at least comprises a first lens (321) and a second lens (322) which are sequentially arranged in a direction of light propagation; the first lens (321) has a positive optical power, a distance between the first lens (321) and the light source (310) being less than a focal length of the first lens (321), and the first lens (321) being configured for expanding a light beam emitted by the light source (310); the second lens (322) has a positive optical power and is configured for collimating a light beam emitted by the first lens (321); a liquid crystal display panel (500) configured for modulating light emitted by the illumination lens group (320) to form a display image; and an imaging lens group (40) configured for imaging the display image. The vehicle light projection apparatus helps improve display image luminance.

Description

Vehicle headlight projection device

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411731791.5, filed on November 28, 2024, entitled "A Vehicle Light Projection Device", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of projection technology, and in particular to a vehicle headlight projection device. Background Technology

[0004] Automotive headlight projection is a projection technology applied to the headlights or taillights of automobiles. By installing a projection device inside the headlight, specific images, signs, or information can be projected onto the surrounding environment, achieving diverse functions according to user needs and possessing broad application prospects. For example, during nighttime driving, headlight projection devices can project navigation information, distance indicators, obstacle warnings, and other driving information onto the road surface for the driver's convenience, assisting driving and providing safety warnings. Alternatively, headlight projection devices can display patterns, text, signs, and play videos, providing users with personalized entertainment functions. They can also be used for interaction or communication with other vehicles or pedestrians. However, traditional projection equipment is difficult to apply to automotive headlight projection due to its large size, and existing headlight projection equipment suffers from low brightness and low image quality. Summary of the Invention

[0005] This application provides a vehicle headlight projection device for improving the brightness of the projected image.

[0006] This application provides a vehicle headlight projection device, including:

[0007] An illumination assembly includes a light source and an illumination lens group; the illumination lens group is located on the light-emitting side of the light source; the illumination lens group includes at least a first lens and a second lens arranged sequentially along the light path propagation direction, both the first lens and the second lens having positive optical power, and the distance between the first lens and the light source being less than the focal length of the first lens;

[0008] The display panel, located on the light-emitting side of the illumination mirror group, is used to modulate the light emitted from the illumination mirror group to form a display image;

[0009] An imaging lens assembly, located on the light-emitting side of the display panel, is used to image the displayed image.

[0010] In some embodiments of this application, the light-incident surface of the first lens is a plane or a convex surface, and the light-exiting surface of the first lens is a convex surface; when the light-incident surface of the first lens is a convex surface, the radius of curvature of the light-incident surface of the first lens is greater than the radius of curvature of the light-exiting surface of the first lens.

[0011] In some embodiments of this application, the light-incident surface of the second lens is a plane or a convex surface, and the light-exit surface of the second lens is a convex surface; when the light-incident surface of the second lens is a convex surface, the radius of curvature of the light-incident surface of the second lens is greater than the radius of curvature of the light-exit surface of the first lens.

[0012] In some embodiments of this application, the first lens and the second lens are spherical lenses, or the first lens and / or the second lens are aspherical lenses.

[0013] In some embodiments of this application, the incident surface of the aspherical lens is a plane, and the exit surface of the aspherical lens is a freeform surface.

[0014] In some embodiments of this application, the optical thickness of a lens with a smaller distance from the light source is greater than the optical thickness of a lens with a larger distance from the light source, wherein the optical thickness is the product of the thickness of the lens on the optical axis and the refractive index of the lens.

[0015] In some embodiments of this application, the aperture of a lens with a larger distance from the light source in the direction perpendicular to the optical axis is larger than the aperture of a lens with a smaller distance from the light source in the direction perpendicular to the optical axis.

[0016] In some embodiments of this application, the distance between two adjacent lenses with a greater distance from the light source on the optical axis is greater than the distance between two adjacent lenses with a smaller distance from the light source on the optical axis.

[0017] In some embodiments of this application, the illumination mirror assembly further includes:

[0018] The third lens is located on the light-emitting side of the second lens, and the third lens is a Fresnel lens.

[0019] In some embodiments of this application, the distance between the third lens and the second lens on the optical axis is less than or equal to the distance between the second lens and the first lens on the optical axis.

[0020] In some embodiments of this application, the light-incident surface of the third lens is a plane, and the light-exit surface of the third lens is a textured surface.

[0021] In some embodiments of this application, the length of the illumination lens group on the optical axis is less than or equal to 15 mm.

[0022] In some embodiments of this application, the imaging lens group includes a plurality of imaging lenses arranged sequentially along the optical path propagation direction, the plurality of imaging lenses including at least one Fresnel lens, the at least one Fresnel lens being located on the side of the imaging lens group closer to the display panel.

[0023] In some embodiments of this application, the imaging lens group includes a first imaging lens, a second imaging lens, and a third imaging lens arranged sequentially along the optical path propagation direction; the first imaging lens is a Fresnel lens, the second imaging lens is a spherical lens, and the third imaging lens is an aspherical lens.

[0024] In some embodiments of this application, the light-incident surface of the first imaging lens is a textured surface, and the light-exiting surface of the first imaging lens is a plane; the light-incident surface of the second imaging lens is a convex surface, and the light-exiting surface of the second imaging lens is a concave surface; the light-incident surface of the third imaging lens is a concave surface, and the light-exiting surface of the third imaging lens is a convex surface.

[0025] In some embodiments of this application, the imaging lens group includes a first imaging lens, a second imaging lens, and a third imaging lens arranged sequentially along the optical path propagation direction. The first imaging lens is a Fresnel lens, the second imaging lens is a Fresnel lens, and the third imaging lens is a spherical lens.

[0026] In some embodiments of this application, the light-incident surface of the first imaging lens is a textured surface, and the light-exiting surface of the first imaging lens is a flat surface; the light-incident surface of the second imaging lens is a textured surface, and the light-exiting surface of the second imaging lens is a flat surface; the light-incident surface of the third imaging lens is a concave surface, and the light-exiting surface of the third imaging lens is a convex surface.

[0027] In some embodiments of this application, the imaging lens group includes a first imaging lens, a second imaging lens, a third imaging lens, and a fourth imaging lens arranged sequentially along the optical path propagation direction. The first imaging lens is a Fresnel lens, the second imaging lens is a spherical lens, the third imaging lens is a spherical lens, and the fourth imaging lens is a spherical lens.

[0028] In some embodiments of this application, the light-incident surface of the first imaging lens is a textured surface, and the light-exiting surface of the first imaging lens is a plane; the light-incident surface of the second imaging lens is a convex surface, and the light-exiting surface of the second imaging lens is a concave surface; the light-incident surface of the third imaging lens is a concave surface, and the light-exiting surface of the third imaging lens is a convex surface; the light-incident surface of the fourth imaging lens is a concave surface, and the light-exiting surface of the fourth imaging lens is a convex surface.

[0029] In some embodiments of this application, the focal length of the first imaging lens is less than or equal to 35 mm, and the length of the imaging lens group on the optical axis is less than or equal to 30 mm.

[0030] In some embodiments of this application, the illumination lens group and the imaging lens group satisfy the following relationship:

[0031] Wherein, F represents the aperture number of the imaging lens group, F≤2.0, f represents the focal length of the imaging lens group, D represents the entrance pupil diameter of the imaging lens group, n represents the refractive index of air, and θ represents the emission angle of the light beam emitted by the illumination lens group.

[0032] The beneficial effects of this application are as follows:

[0033] The vehicle headlight projection device provided in this application includes: a light source; an illumination lens assembly located on the light-emitting side of the light source; the illumination lens assembly includes at least a first lens and a second lens arranged sequentially along the light path propagation direction; the first lens has positive optical power, the distance between the first lens and the light source is less than the focal length of the first lens, and the first lens is used to expand the beam emitted from the light source; the second lens has positive optical power and is used to collimate the beam emitted from the first lens; a display panel located on the light-emitting side of the illumination lens assembly, used to modulate the light emitted from the illumination lens assembly to form a display image; and an imaging lens assembly located on the light-emitting side of the display panel, used to image the display image. The beam emitted from the light source passes through two lenses with positive optical power in the illumination lens assembly, and their emission angles decrease sequentially, resulting in more concentrated light energy on the display panel, which is beneficial for improving the brightness of the display image. This, in turn, improves the brightness of the projected image after the display image is imaged by the imaging lens assembly. Furthermore, the illumination lens assembly has a relatively small number of lenses, which can meet the miniaturization design requirements of vehicle headlight projection products. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 is a structural schematic diagram of a vehicle headlight projection device provided in an embodiment of this application;

[0036] Figure 2 is a schematic diagram of a lighting component provided in an embodiment of this application;

[0037] Figure 3 is a structural schematic diagram of another lighting component provided in an embodiment of this application;

[0038] Figure 4 is an optical path diagram of another lighting component provided in an embodiment of this application;

[0039] Figure 5 is a light spot intensity distribution diagram at a liquid crystal display panel provided in an embodiment of this application;

[0040] Figure 6 is a light spot illuminance distribution diagram at a liquid crystal layer provided in an embodiment of this application;

[0041] Figure 7 is an illuminance distribution diagram of light not utilized by the liquid crystal layer provided in an embodiment of this application;

[0042] Figure 8 is a light spot intensity distribution diagram at another liquid crystal display panel provided in an embodiment of this application;

[0043] Figure 9 is a light spot illuminance distribution diagram of another liquid crystal display panel provided in an embodiment of this application;

[0044] Figure 10 is a schematic diagram of an imaging lens assembly provided in an embodiment of this application;

[0045] Figure 11 is a dot diagram provided in an embodiment of this application;

[0046] Figure 12 is a modulation transfer function curve provided in an embodiment of this application;

[0047] Figure 13 is a geometric distortion diagram provided in an embodiment of this application;

[0048] Figure 14 is a schematic diagram of the direct projection effect of an imaging lens group provided in an embodiment of this application;

[0049] Figure 15 is a schematic diagram of the side projection effect of an imaging lens group provided in an embodiment of this application;

[0050] Figure 16 is a schematic diagram of another imaging lens assembly provided in an embodiment of this application;

[0051] Figure 17 is a schematic diagram of another imaging lens assembly provided in an embodiment of this application;

[0052] Figure 18 is a schematic diagram of the structure of an optical device in a vehicle headlight projection device according to an embodiment of this application;

[0053] Figure 19 is a schematic diagram of the structure of an optical device in a vehicle headlight projection device according to an embodiment of this application;

[0054] Figure 20 is a schematic diagram of the structure of an optical device in a vehicle headlight projection device according to an embodiment of this application;

[0055] Figure 21 is a schematic diagram of the structure of an optical device in a vehicle headlight projection device according to an embodiment of this application;

[0056] Figure 22 is a schematic diagram of the structure of an optical device in a vehicle headlight projection device according to an embodiment of this application;

[0057] Explanation of reference numerals in the attached drawings: 100-Housing, 200-Heat dissipation device, 300-Illumination assembly, 310-Light source, 320-Illumination lens group, 321-First lens, 322-Second lens, 323-Third lens, 400-Projection lens, 40-Imaging lens group, 410-First imaging lens, 420-Second imaging lens, 430-Third imaging lens, 440-Fourth imaging lens, S-Aperture stop, 500-Display panel / Liquid crystal display panel, 510-First substrate, 520-Liquid crystal layer, 530-Second substrate. Detailed Implementation

[0058] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the application will be further described below in conjunction with the accompanying drawings and embodiments. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. Terms describing position and direction described in this application are illustrative based on the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this application. The accompanying drawings of this application are for illustrating relative positional relationships only and do not represent actual scale.

[0059] Figure 1 is a structural schematic diagram of a vehicle headlight projection device provided in an embodiment of this application.

[0060] As shown in Figure 1, the vehicle headlight projection device includes an illumination component 300, a display panel 500, and a projection lens 400. The illumination component 300, display panel 500, and projection lens 400 are integrated within a housing 100. A heat sink can be installed on one side of the housing 100 to dissipate heat from the internal components, ensuring normal operation and extending the device's lifespan. In practical applications, the projection lens 400 can also be designed to be detachable to accommodate different needs. The specific structure of the housing 100 and the heat sink can be designed according to actual requirements. This application only designs the optical components of the vehicle headlight projection device, namely the illumination component 300, display panel 500, and projection lens 400.

[0061] The illumination assembly 300 includes a light source 310 and an illumination mirror group 320. The illumination mirror group 320 is located on the light-emitting side of the light source 310. The light emitted from the light source 310 is adjusted by the illumination mirror group 320 to provide uniform illumination with sufficient brightness for the liquid crystal display panel 500. The display panel 500 is located on the light-emitting side of the illumination assembly 300 and can be a liquid crystal display panel. The liquid crystal display panel 500 includes a first substrate and a second substrate disposed opposite to each other. An accommodating space is formed between the first substrate and the second substrate to fill the liquid crystal layer. To avoid liquid crystal leakage, the size of the first substrate and the second substrate is larger than the size of the liquid crystal layer. The liquid crystal display panel 500 modulates the transmittance and reflectance of the incident light based on the birefringence effect of the liquid crystal. The light emitted from the illumination mirror group 320 is modulated by the liquid crystal display panel 500 to form a display image. The projection mirror group is located on the light-emitting side of the liquid crystal display panel 500 and is used to image the display image to form a projected image at a set distance for the user to view.

[0062] It is evident that the performance of the illumination component 300 and the projection lens 400 are crucial factors determining the quality of the projected image. Since the liquid crystal layer is the actual component used to modulate light in the liquid crystal display panel 500, the size of the beam emitted from the illumination component 300 should be as close as possible to the size of the liquid crystal layer to fully utilize light and improve the brightness of the displayed image. The brightness of the displayed image directly determines the brightness of the projected image formed by the projection lens 400. Therefore, this application designs the lens composition in the illumination component 300 and the projection lens 400 to achieve high-brightness projection display.

[0063] The following describes several embodiments of the lighting assembly 300.

[0064] Lighting component example 1:

[0065] Figure 2 is a schematic diagram of the structure of the lighting assembly provided in the embodiment of this application.

[0066] As shown in Figure 2, the lighting assembly 300 includes a light source 310 and an illumination mirror group 320, with the illumination mirror group 320 located on the light-emitting side of the light source 310.

[0067] In this embodiment, the light source 310 can be a square light-emitting diode (LED) light source. The LED light source includes LED chips arranged in a 4x4 array to ensure that the brightness of the light source 310 is sufficient to support high-brightness display and maintain a low cost. The light source 310 emits a square light spot, and the shape of the light spot matches the shape of the liquid crystal display panel 500, which is easier to control and helps to improve the uniformity of light spot energy and illuminance, thereby improving the display quality. In practical applications, the number, type, shape, and arrangement of the light-emitting devices in the light source 310 can be selected according to the brightness requirements of the product, and this embodiment does not limit this.

[0068] The illumination lens assembly 320 includes a first lens 321 and a second lens 322 arranged sequentially along the optical path propagation direction. Both the first lens 321 and the second lens 322 have positive optical power. Lenses with positive optical power can compress the light beam, improve the collimation of the light beam, and deflect the light rays emitted at a larger angle in the light beam towards the optical axis. As a result, the light beam emitted from the light source 310 has a smaller emission angle after passing through the first lens 321, and the light beam energy is more concentrated. The light beam emitted from the first lens 321 has a further smaller emission angle after passing through the second lens 322, and the light beam energy is further concentrated.

[0069] According to the imaging principle of a lens with positive optical power, when the distance between the object and the lens is within one focal length of the lens, a magnified virtual image can be formed on the same side as the object. The distance between the virtual image and the lens, as well as the size of the virtual image, are related to the distance between the object and the lens. The greater the distance between the object and the lens, the larger the virtual image. Therefore, it can be understood that by adjusting the distance between the light source 310 and the lens within the focal length range of the lens, the emission angle of the light beam emitted by the lens can be adjusted so that the light spot formed by the light beam emitted by the lens reaches the required size.

[0070] In this embodiment, the distance between the first lens 321 and the light source 310 is less than the focal length of the first lens 321. By setting the distance between the first lens 321 and the light source 310 to a predetermined value, the size of the light spot formed by the beam emitted from the first lens 321 can be made similar to the size of the liquid crystal layer 520 in the liquid crystal display panel 500. For example, the focal length of the first lens 321 is 13mm, and the distance between the first lens 321 and the light source 310 is 0-1mm. In one possible implementation, the first lens 321 is disposed close to the light-emitting surface of the light source 310.

[0071] In this embodiment, the illumination lens assembly 320 includes a first lens 321 and a second lens 322 with positive optical power. The light beam emitted from the light source 310 passes sequentially through the first lens 321 and the second lens 322, with the emission angle of the light beam decreasing sequentially. This concentrates the light beam energy incident on the liquid crystal display panel 500 within a smaller range. Furthermore, the size of the light beam is adjusted by the first lens 321 to be close to that of the liquid crystal display panel 500, and then collimated by the second lens 322, further approximating the size of the liquid crystal display panel 500. This allows the size of the light spot projected onto the liquid crystal display panel 500 to match the size of the liquid crystal display panel 500, improving the utilization rate of the light emitted from the light source 310, achieving high-brightness display, and thus improving the brightness of the projected image. In addition, the illumination lens assembly 320 includes only two lenses, which helps reduce the size of the illumination lens assembly 320, meeting the design requirements for miniaturization of the projection device.

[0072] In specific implementations, the illumination lens group 320 may also include a greater number of lenses for further adjusting the size, collimation, and uniformity of the beam emitted by the second lens 322. This application embodiment does not limit the number of lenses in the illumination lens group 320. The following illumination component embodiments 2 and 5 will specifically describe the case where the illumination component 320 includes more lenses.

[0073] As shown in Figure 2, in this embodiment, the light source 310, the first lens 321, and the second lens 322 are coaxially arranged. This coaxial design helps maintain the symmetry of the light beam, thereby improving the uniformity of the displayed image and also reducing the size of the illumination lens group 320. For ease of manufacturing, both the first lens 321 and the second lens 322 can be spherical lenses.

[0074] Specifically, the first lens 321 is a spherical lens, with both its incident and emitting surfaces being spherical. The incident surface of the first lens 321 is either planar or convex, while its emitting surface is convex; that is, the first lens 321 is a plano-convex lens or a biconvex lens. Furthermore, when the incident surface of the first lens 321 is convex, the radius of curvature of its incident surface is greater than the radius of curvature of its emitting surface, allowing the first lens 321 to have positive optical power. In practical applications, to better fit the first lens 321 to the light-emitting surface of the light source 310, and to reduce the distance between the first lens 321 and the light source 310, as well as the overall length of the optical path, the incident surface of the first lens 321 is typically planar. Additionally, setting the lens surface to be planar can reduce the difficulty of lens manufacturing.

[0075] The second lens 322 is a spherical lens, with both its incident and exit surfaces being spherical. The incident surface of the second lens 322 is either a plane or a convex surface, and the exit surface of the second lens 322 is a convex surface. That is, the second lens 322 is a plano-convex lens or a biconvex lens. Furthermore, when the incident surface of the second lens 322 is a convex surface, the radius of curvature of the incident surface of the second lens 322 is greater than the radius of curvature of the exit surface of the first lens 321, so that the second lens 322 can have positive optical power.

[0076] The parameter ranges of each lens in this embodiment are as follows: the radius of curvature of the incident surface of the first lens 321 is greater than 7 mm, the radius of curvature of the emitting surface of the first lens 321 is 4 mm to 7 mm, the thickness of the first lens 321 along the optical axis is 2.9 mm to 4 mm, and the aperture of the first lens 321 in the direction perpendicular to the optical axis is 3.8 mm to 20 mm. In one possible embodiment, the incident surface of the first lens 321 is planar, the radius of curvature of the emitting surface of the first lens 321 is 6.873 mm, the thickness of the first lens 321 along the optical axis is 2.9 mm, and the aperture of the first lens 321 in the direction perpendicular to the optical axis is 4.5 mm.

[0077] The radius of curvature of the incident surface of the second lens 322 is greater than 40 mm, the radius of curvature of the emitting surface of the second lens 322 is 25 mm to 40 mm, the thickness of the second lens 322 on the optical axis is greater than the thickness of the first lens 321 on the optical axis but less than 5 mm, the aperture of the second lens 322 in the direction perpendicular to the optical axis is greater than the aperture of the first lens 321 in the direction perpendicular to the optical axis, and the distance between the second lens 322 and the first lens 321 on the optical axis is 0 to 4 mm. The distance between the second lens 322 and the first lens 321 on the optical axis is defined as the distance between the incident surface of the second lens 322 and the emitting surface of the first lens 321 on the optical axis. In one possible implementation, the radius of curvature of the light-incident surface of the second lens 322 is 50 mm, the radius of curvature of the light-outceasing surface of the second lens 322 is 25 mm, the thickness of the second lens 322 on the optical axis is 4.7 mm, the aperture of the second lens 322 in the direction perpendicular to the optical axis is 9.5 mm, and the distance between the second lens 322 and the first lens 321 on the optical axis is 3.6 mm.

[0078] Lighting component example 2:

[0079] Figure 3 is a schematic diagram of the structure of the lighting component provided in the embodiment of this application.

[0080] As shown in Figure 3, the difference between this embodiment and the lighting component embodiment 1 is that the lighting lens group 320 also includes a third lens 323. The third lens 323 is located on the light-emitting side of the second lens 322. The third lens 323 is a Fresnel lens. By designing the structure of the textured surface of the Fresnel lens, the emission direction of the light incident into it can be adjusted more precisely. Thus, the third lens 323 can be used to collimate and homogenize the light beam emitted from the second lens 322, further improving the collimation of the light beam emitted to the liquid crystal display panel 500.

[0081] The distance between the third lens 323 and the second lens 322 on the optical axis is less than or equal to the distance between the second lens 322 and the first lens 321 on the optical axis. This is because the lens closer to the light source 310 needs to have a better ability to deflect light, and the larger the angle of light deflection, the longer the beam needs to diverge into the desired state. Therefore, the beam emitted from the second lens 322 only needs a shorter propagation distance than the beam emitted from the first lens 321.

[0082] For example, the distance between the third lens 323 and the second lens 322 on the optical axis and the distance between the second lens 322 and the first lens 321 on the optical axis can satisfy the following proportional relationship: ΔD 12 =ΔD 23 *k, where ΔD 12 ΔD represents the distance between the second lens 322 and the first lens 321 on the optical axis. 23 The distance between the third lens 323 and the second lens 322 on the optical axis is 1≤k≤4. In one possible embodiment, the distance between the third lens 323 and the second lens 322 on the optical axis is 1.15mm, and the distance between the second lens 322 and the first lens 321 on the optical axis is 3.6mm.

[0083] Specifically, the light-incident surface of the third lens 323 can be a flat surface, and the light-exiting surface of the third lens 323 can be a textured surface. The light enters the Fresnel lens from the flat surface and is refracted inside. The structure of the textured surface changes the angle of the light when it exits. In this way, the light enters the Fresnel lens in a more regular manner, which makes it easier to control the state of the light.

[0084] To make the lighting effect of the lighting lens group 320 more intuitive and visible, this application embodiment provides specific design parameters of the lighting component 300 (as shown in Table 1 below), and test results simulated using optical design software based on the design parameters.

[0085] Table 1

[0086] Among them, the surface numbered 0 represents the light source 310, the surfaces numbered 1 to 6 are the lens surfaces through which the light beam emitted from the light source 310 passes in sequence, and the spacing represents the distance between the corresponding numbered surface and the previous surface on the optical axis.

[0087] Figure 4 is a light path diagram of the lighting assembly provided in the embodiment of this application.

[0088] As shown in Figure 4, the light beam emitted from the light source 310 passes through the first lens 321 and gradually diffuses to the required size between the first lens 321 and the second lens 322. After being collimated by the second lens 322, it enters the third lens 323, which further improves the collimation of the light beam.

[0089] Figure 5 is a light spot intensity distribution diagram at the liquid crystal display panel provided in the embodiment of this application.

[0090] The light spot intensity distribution shown in Figure 5 can reflect the energy distribution of the light beam at different emission angles when it propagates to the liquid crystal display panel 500. As can be seen from Figure 5, when the light beam propagates to the light incident surface of the liquid crystal display panel 500, its emission angle is within the range of ±16°. It can be seen that the illumination mirror group 320 provided in this embodiment can concentrate the light beam energy in a small range, with a small degree of light beam divergence, and the light spot energy received by the liquid crystal display panel 500 is higher.

[0091] Specifically, the light source 310 is an LED light source with a light emission angle of 180° (i.e., ±90°). The first lens 321 can reduce the light emission angle of the beam to 160° (i.e., ±80°), the second lens 322 can reduce the light emission angle of the beam to 40° (i.e., ±20°), and the third lens 323 can reduce the light emission angle of the beam to 32° (i.e., ±16°).

[0092] Figure 6 is a light spot illuminance distribution diagram at the liquid crystal layer provided in the embodiment of this application; Figure 7 is an illuminance distribution diagram of light not utilized by the liquid crystal layer provided in the embodiment of this application.

[0093] As can be seen from Figures 6 and 7, the light beam emitted from the light source 310 forms a circular light spot on the light incident surface of the liquid crystal display panel 500 after passing through the illumination mirror group 320. In order to ensure the symmetry of the light spot, in this embodiment, the central axis of the liquid crystal display panel 500 coincides with the optical axis of the light beam emitted from the illumination mirror group 320.

[0094] In the prior art, in order to make the light spot cover the liquid crystal layer 520 (the light spot is indicated by a dashed line in Figure 6), the light spot is usually at least circumscribed to the edge of the liquid crystal layer 520. This inevitably causes some light loss. However, in the embodiment of this application, near the corner of the liquid crystal layer 520, the edge of the light spot is inside the edge of the liquid crystal layer 520, and near the side of the liquid crystal layer 520, the edge of the light spot slightly exceeds the edge of the liquid crystal layer 520. In this way, only a small portion of light cannot be used by the liquid crystal layer 520, as shown in Figure 7. Compared with the prior art, there is less light loss, the brightness of the light spot is higher, and as can be seen from Figure 6, the light spot received by the liquid crystal layer 520 has better uniformity.

[0095] In this embodiment, the shapes and dimensions of the main components in the liquid crystal display panel 500 are as follows: the first substrate 510 and the first polarizing layer attached to the first substrate 510 are square structures with a length of 27 mm and a width of 27 mm; the liquid crystal layer 520 is a 0.85-inch square structure, i.e., a length of 15.27 mm and a width of 15.27 mm; and the second substrate 530 and the second polarizing layer attached to the second substrate 530 are square structures with a length of 27 mm and a width of 27 mm. The light beam emitted from the illumination lens group 320 can form a circular light spot with a radius of 9 mm on the light-incident surface of the liquid crystal display panel 500. The size of the light spot is similar to the size of the liquid crystal layer 520, resulting in high light utilization and improving the brightness of the displayed image.

[0096] Tests have shown that when using the illumination lens group 320 provided in this application embodiment, the geometric efficiency of light can reach over 80%. Geometric efficiency is defined as the ratio of the luminous flux that the liquid crystal layer 520 can utilize to the total luminous flux emitted by the light source 310. When using the coaxial scheme shown in Figure 3 and Table 1, the geometric efficiency of light can reach 86.7%. In conventional liquid crystal projection devices, the geometric efficiency of light is only 75%. The illumination lens group 320 provided in this application embodiment has a higher utilization rate of light.

[0097] Lighting component example 3:

[0098] In this embodiment of the application, at least one of the first lens 321 or the second lens 322 can be an aspherical lens. For example, the first lens 321 is an aspherical lens and the second lens 322 is a spherical lens. In this case, the light-incident surface of the first lens 321 can be a plane and the light-outceasing surface of the first lens 321 can be a freeform surface. Alternatively, the first lens 321 is a spherical lens and the second lens 322 is an aspherical lens. In this case, the light-incident surface of the second lens 322 can be a plane and the light-outceasing surface can be a freeform surface. Or, both the first lens 321 and the second lens 322 can be aspherical lenses.

[0099] This embodiment of the application uses an aspherical lens as an example to simulate the light spot received by the liquid crystal display panel 500. The light-incident surface of the first lens 321 is a plane, and the light-exit surface is a freeform surface. The shape of this freeform surface is symmetrical about the optical axis to ensure that the shape of the light spot received by the liquid crystal display panel 500 is symmetrical. The design parameters of the first lens 321 are as follows: the thickness of the first lens 321 along the optical axis is 5.5mm to 7.5mm, the aperture in the direction perpendicular to the optical axis is 7mm to 8mm, the distance between the first lens 321 and the light source 310 along the optical axis is 0.1mm to 0.5mm, and the distance between the first lens 321 and the second lens 322 along the optical axis is 3mm to 4mm.

[0100] Figure 8 is a light spot intensity distribution diagram at the liquid crystal display panel provided in the embodiment of this application.

[0101] As shown in Figure 8, in this embodiment of the application, when the light beam emitted from the illumination lens group 320 propagates to the light incident surface of the liquid crystal display panel 500, the divergence angle of the light beam is ±13°. It can be seen that by setting an aspherical lens in the illumination component 300, the light beam can be further compressed, making the light beam energy more concentrated and meeting the higher brightness requirements.

[0102] Figure 9 is a light spot illuminance distribution diagram of the liquid crystal display panel provided in the embodiment of this application.

[0103] As shown in Figure 6, to meet the high brightness requirement, the light spot may not be able to cover a small area near the corner of the liquid crystal layer 520, resulting in dark corners in the displayed image. As shown in Figure 9, by adapting the surface shape of the aspherical lens, the direction of light emission can be adjusted more precisely. In particular, the edge light in the beam can be adjusted in a targeted manner, so that when the beam is projected onto the liquid crystal display panel 500, a rectangular light spot can be formed, thereby filling in the dark corners of the displayed image, further improving the light utilization rate, and balancing high brightness with the integrity and uniformity of the displayed image.

[0104] Lighting component example 4:

[0105] In this embodiment of the application, at least one of the light source 310, the first lens 321 and the second lens 322 may be non-coaxial with other devices. In this case, at least one of the first lens 321 and the second lens 322 needs to be an aspherical lens.

[0106] The non-coaxial design can adapt to irregular shapes inside the headlights, meeting personalized design needs. The aspherical lens can more precisely adjust the direction of light propagation, making the beam emitted from the lighting component 300 symmetrical about the optical axis, thereby giving the light spot projected onto the LCD panel 500 better uniformity.

[0107] The following describes various embodiments of the projection lens 400. The projection lens 400 images the display screen through the imaging lens group 40 to form a projected image. The imaging lens group 40 includes a plurality of imaging lenses arranged sequentially along the light path propagation direction. The plurality of imaging lenses include at least one Fresnel lens. The at least one Fresnel lens is located on the side of the imaging lens group 40 closer to the liquid crystal display panel 500. The Fresnel lens has the characteristics of strong light focusing ability, low thickness and customizable design. It can make more precise adjustments to the light, provide clear imaging and high brightness, which is conducive to improving the imaging quality and reducing the number of lenses in the imaging lens group 40, meeting the design requirements of high brightness and small size.

[0108] Lighting component example 5:

[0109] In this embodiment, the illumination lens assembly 320 further includes at least one fourth lens, which is located between the second lens 322 and the third lens 323. The fourth lens can be used to further adjust the size of the beam emitted from the second lens 322 and improve the collimation of the beam.

[0110] Based on the design concept of the embodiments of this application, in the above-described lighting component embodiments, each lens in the lighting lens group 320 should satisfy the following rules:

[0111] Rule 1: Except for the third lens 323, the optical thickness of a lens with a smaller distance from the light source is greater than that of a lens with a larger distance from the light source. The optical thickness is the product of the lens's thickness along the optical axis and its refractive index. The refractive index of the lens is determined by the material used. When the materials used are the same, the lens closer to the light source 310 has a greater thickness along the optical axis. For example, the optical thickness of the first lens 321 is greater than that of the second lens 322.

[0112] The greater the optical thickness of a lens, the greater the optical path of the light within the lens, and the more obvious the change in the direction of the light. Therefore, it can be understood that the closer the lens is to the light source 310, the greater the divergence of the light beam. Thus, the closer the lens is to the light source 310, the greater its optical thickness should be, so that the light can achieve a sufficiently large optical path at a shorter physical distance, thereby helping to reduce the physical length of the projection device.

[0113] Rule 2: Lenses with a larger distance from the light source 310 have a larger aperture in the direction perpendicular to the optical axis than lenses with a smaller distance from the light source 310 in the same direction. For example, the third lens 323 has a larger aperture in the direction perpendicular to the optical axis than the second lens 322, and the second lens 322 has a larger aperture in the direction perpendicular to the optical axis than the first lens 321.

[0114] This is because although both the first lens 321 and the second lens 322 can reduce the divergence angle of the beam, the overall trend of the beam is still divergent. Therefore, the size of the light spot projected onto the first lens 321 by the beam emitted from the light source 310 is smaller than the size of the light spot projected onto the second lens 322 by the beam emitted from the first lens 321. Therefore, to avoid light loss, the aperture of the second lens 322 should be larger than the aperture of the first lens 321 so that all the light emitted from the first lens 321 can enter the second lens 322. Similarly, if the beam still has a divergent tendency after passing through the second lens 322, the aperture of the fourth lens arranged along the light path should increase sequentially in the direction perpendicular to the optical axis to avoid light loss.

[0115] Theoretically, the radius of curvature of a spherical lens can be calculated based on its thickness and aperture. However, due to manufacturing limitations, the two end surfaces of the lens are planes perpendicular to the optical axis. These planes connect the light-incident and light-exit surfaces of the lens. Therefore, when designing a lens, considering the width of these planes along the optical axis can further limit the radius of curvature of the light-incident and light-exit surfaces of the spherical lens. In this application, when each lens in the illumination assembly 320 is a spherical lens, the radius of curvature of the light-incident and light-exit surfaces of the first lens 321 is smaller than that of the second lens 322. The farther the lens is from the light source 310, the larger its radius of curvature of the light-incident and light-exit surfaces.

[0116] Rule 3: Except for the third lens 323, the optical axis spacing between two adjacent lenses with a larger distance from the light source 310 is greater than the optical axis spacing between two adjacent lenses with a smaller distance from the light source 310. For example, the optical axis spacing between the second lens 322 and its adjacent fourth lens is greater than the optical axis spacing between the second lens 322 and the first lens 321. Furthermore, the optical axis spacing between the second lens 322 and the first lens 321 is greater than the optical axis spacing between the first lens 321 and the light source 310.

[0117] This is because the beam's emission angle decreases after passing through the lens, and it needs to travel a certain distance to form a light spot of the required size. In the illumination lens group 320, the first lens 321 mainly undertakes the function of adjusting the light spot size. The deflection angle of the light through the first lens 321 is relatively larger than that of the lenses in the subsequent optical path. Therefore, the distance between two adjacent lenses farther from the light source 310 on the optical axis should be greater than the distance between two adjacent lenses closer to the light source 310 on the optical axis.

[0118] Imaging lens assembly example 1:

[0119] Figure 10 is a schematic diagram of the imaging lens assembly provided in an embodiment of this application. Figure 10 illustrates the lens composition and light propagation path in the imaging lens assembly 40. It is understood that, to avoid overly complicated illustrations, Figure 10 only shows half of the light beam emitted from the liquid crystal display panel to the imaging lens assembly. The other half of the light beam is symmetrical about the optical axis to the half beam shown in the figure. The same applies to the following embodiments.

[0120] As shown in Figure 10, in this embodiment of the application, the imaging lens group 40 includes a first imaging lens 410, a second imaging lens 420, and a third imaging lens 430 arranged sequentially along the optical path propagation direction. The first imaging lens 410 is a Fresnel lens, the second imaging lens 420 is a spherical lens, and the third imaging lens 430 is an aspherical lens. The displayed image is sequentially imaged by the first imaging lens 410, the second imaging lens 420, and the third imaging lens 430. For ease of description, the image formed by the first imaging lens 410 is referred to as the first image, the image formed by the first imaging lens 420 is referred to as the second image, and the image formed by the second image by the third imaging lens 430 is referred to as the third image.

[0121] In this system, the light emitted from the liquid crystal display panel 500 is parallel or approximately parallel to the first imaging lens 410, which converges the light, forming a magnified virtual image of the displayed image. An aperture S is provided between the second imaging lens 420 and the third imaging lens 430. The second imaging lens 420 further converges the light, allowing the light beam to converge and then diverge between the two lenses, enabling it to pass through the aperture S into the third imaging lens 430. The first image is formed by the second imaging lens 420, creating a reduced real image, while the second image is located between the second and third imaging lenses 420 and 430. The third lens 323 adjusts the beam size to meet the magnification requirements of the projection device. The second image is formed by the third imaging lens 430, creating a magnified real image. Furthermore, the third lens 323 employs an aspherical design to correct aberrations such as chromatic aberration, distortion, spherical aberration, coma, and astigmatism, thereby improving image quality.

[0122] To achieve the above functions, the specific designs of the first imaging lens 410, the second imaging lens 420, and the third imaging lens 430 are as follows:

[0123] The first imaging lens 410 is a Fresnel lens, with a textured incident surface and a flat exit surface. The distance between the first imaging lens 410 and the liquid crystal display panel 500 is less than the focal length of the first imaging lens 410, so that the first image is a virtual image. Furthermore, the focal length of the first imaging lens 410 should be set to a relatively small value to meet the design requirements of a small volume. Specifically, the focal length of the first imaging lens 410 is less than or equal to 35mm, and the distance between the first imaging lens 410 and the liquid crystal display panel 500 is 4mm to 8mm. The orthographic projection of the liquid crystal display panel 500 along the optical axis falls within the range of the orthographic projection of the first imaging lens 410 along the optical axis. That is, the size of the first imaging lens 410 should be greater than or equal to the size of the liquid crystal display panel 500, so that all the light emitted from the liquid crystal display panel 500 can be incident on the first imaging lens 410.

[0124] In one possible implementation, the focal length of the first imaging lens 410 is 25mm, the distance between the first imaging lens 410 and the liquid crystal display panel 500 is 4mm, the length of the first imaging lens 410 is 27mm, the width is 23mm, and the thickness of the first imaging lens 410 is 1.6mm.

[0125] The second imaging lens 420 is a spherical lens with a convex incident surface and a concave exit surface. Specifically, the radius of curvature of the incident surface of the second imaging lens 420 is 10mm to 12mm, the radius of curvature of the exit surface is 45mm to 47mm, the thickness of the second imaging lens 420 along the optical axis is less than or equal to 6mm, and the aperture of the second imaging lens 420 in the direction perpendicular to the optical axis can be smaller than the width of the first imaging lens 410 in the direction perpendicular to the optical axis.

[0126] In one possible implementation, the radius of curvature of the incident surface of the second imaging lens 420 is 11.185 mm. The radius of curvature of the emitting surface of the second imaging lens 420 is 46.978 mm, the thickness of the second imaging lens 420 is 3 mm, and the aperture of the second imaging lens 420 in the direction perpendicular to the optical axis is 15 mm.

[0127] The third imaging lens 430 is an aspherical lens, with a concave incident surface and a convex exit surface, and both its incident and exit surfaces are aspherical. In this embodiment, the parameters of the incident and exit surfaces of the third lens 323 are constants and satisfy the formula for an even-order 8th-order aspherical surface. Furthermore, the thickness of the third lens 323 along the optical axis is less than the thickness of the second lens 322 along the optical axis. In one possible implementation, the thickness of the third lens 323 along the optical axis is 5 mm. The aperture of the third lens 323 in the direction perpendicular to the optical axis is less than the aperture of the second lens 322 in the direction perpendicular to the optical axis. In one possible implementation, the aperture of the third lens 323 in the direction perpendicular to the optical axis is 12.6 mm. The distance between the third imaging lens 430 and the second imaging lens 420 should be greater than the distance between the second imaging lens 420 and the first imaging lens 410. For example, the distance between the third lens 323 and the second lens 322 along the optical axis and the distance between the second lens 322 and the first lens 321 along the optical axis can satisfy the following proportional relationship: Δd 12 =Δd 23 *k, where Δd 12 Δd represents the distance between the second imaging lens 420 and the first imaging lens 410 on the optical axis. 23 The distance between the third imaging lens 430 and the second imaging lens 420 on the optical axis is 0 ≤ k ≤ 0.7. In one possible embodiment, the distance between the third imaging lens 430 and the second imaging lens 420 on the optical axis is 12.885 mm.

[0128] To make the imaging effect of the imaging lens group 40 more intuitive and visible, this application embodiment provides specific design parameters of the imaging lens group (as shown in Table 2 below), and test results simulated using optical design software based on the design parameters.

[0129] Table 2

[0130] Among them, surfaces numbered 1 to 6 are the surfaces of the imaging lens through which the light beam emitted from the liquid crystal display panel 500 passes in sequence, and the spacing represents the distance between the corresponding numbered surface and the previous surface on the optical axis. The even-order aspherical coefficients satisfied by the incident and emitting surfaces of the third lens 323 are shown in Table 3 below:

[0131] Table 3

[0132] Figure 11 is a dot diagram provided in an embodiment of this application.

[0133] Figure 11 simulates the distribution of the landing points of red light (wavelength 0.656273 mm), green light (wavelength 0.587562 mm), and blue light (wavelength 0.486133 mm) emitted from the liquid crystal display panel 500 on different image planes after passing through the imaging lens group. As can be seen from Figure 11, on each image plane, the image points are concentrated in a small area, and the root mean square radius (RMS radius) of the image points on each image plane is smaller than the side length of a single display pixel of the liquid crystal display panel 500 (the shape of a single display pixel is a square with a length of 150 μm and a width of 150 μm). This indicates that the blurring of the image is small, the images formed by adjacent display pixels through the imaging lens group 40 do not overlap, and the clarity of the projected image is good.

[0134] Figure 12 is a modulation transfer function curve provided in an embodiment of this application.

[0135] As shown in Figure 12, for light in the 0.4861μm to 0.6563μm band, the modulation transfer function (MTF) values ​​of the imaging lens group 40 at different spatial frequencies are all greater than 0.2, which can meet the requirements for the clarity and contrast of the projected image.

[0136] Figure 13 is a geometric distortion diagram provided in an embodiment of this application.

[0137] As shown in Figure 13 and the simulation test results, the maximum geometric distortion of the image formed by the imaging lens group 40 is 0.7172%, which is less than 1%. The geometric shape of the image deviates from the original shape (i.e. the shape of the displayed image) to a low extent, and the image quality is high.

[0138] Figure 14 is a schematic diagram of the direct projection effect of the imaging lens group provided in the embodiment of this application. As can be seen from Figure 14, when light shines vertically or nearly vertically onto the surface of an object, the shape of the light spot imaged by the imaging lens group 40 in the embodiment of this application is regular and approximately symmetrically distributed, and the energy distribution of the light spot is relatively uniform, and the direct projection effect meets the requirements.

[0139] Figure 15 is a schematic diagram of the side projection effect of the imaging lens group provided in the embodiment of this application. As can be seen from Figure 15, when the light shines on the surface of the object at a certain angle (not perpendicular), the shape distortion of the light spot imaged by the imaging lens group 40 in the embodiment of this application is small, and the energy distribution of the light spot is not much different. The side projection effect meets the requirements.

[0140] Imaging lens assembly example 2:

[0141] Figure 16 is a schematic diagram of the imaging lens group provided in an embodiment of this application. As shown in Figure 16, in this embodiment of the application, the imaging lens group 40 includes a first imaging lens 410, a second imaging lens 420 and a third imaging lens 430 arranged sequentially along the optical path propagation direction, wherein the first imaging lens 410 is a Fresnel lens, the second imaging lens 420 is a Fresnel lens and the third imaging lens 430 is a spherical lens.

[0142] The difference between this embodiment and Embodiment 1 is that the second imaging lens 420 can be a Fresnel lens. By designing the textured surface of the second imaging lens 420, the second imaging lens 420 can also have the function of reducing aberrations. In this case, the third imaging lens 430 can be a spherical lens, thereby reducing the design difficulty and production cost.

[0143] Specifically, in this embodiment, the first imaging lens 410 has a textured incident surface and a planar exiting surface; the second imaging lens 420 has a textured incident surface and a planar exiting surface; and the third imaging lens 430 has a concave incident surface and a convex exiting surface. Light enters the Fresnel lens through its textured surface, and the small planes at different angles of the textured surface can be used to initially adjust the angle of the light. After propagating inside the Fresnel lens, the light exits through the planar surface. This method allows for earlier directional control of the light, facilitating imaging with subsequent lenses in the imaging lens group 40.

[0144] The parameter ranges of each imaging lens in this embodiment are as follows: the thickness of the first imaging lens 410 is 1.6mm to 1.7mm, the distance between the first imaging lens 410 and the liquid crystal display panel 500 is greater than or equal to 4mm, and the length and width of the first imaging lens 410 are greater than the length and width of the liquid crystal display panel 500. For example, the length and width of the first imaging lens 410 are 22mm and 22mm respectively; the thickness of the second imaging lens 420 is 1.6mm to 1.7mm, and the distance between the first imaging lens 410 and the liquid crystal display panel 500 is greater than or equal to 4mm. The length and width of the second imaging lens 420 are greater than the length and width of the liquid crystal display panel 500. The width is less than or equal to the length and width of the liquid crystal display panel 500; the distance between the second imaging lens 420 and the first imaging lens 410 on the optical axis is 11mm to 12mm; the radius of curvature of the light-incident surface of the third imaging lens 430 is 101mm to 103mm; the radius of curvature of the light-outceasing surface of the third lens 323 is 23mm to 25mm; the thickness of the third imaging lens 430 on the optical axis is 5mm; and the distance between the third imaging lens 430 and the second imaging lens 420 on the optical axis is 16mm to 17mm.

[0145] Imaging lens assembly example 3:

[0146] Figure 17 is a schematic diagram of the imaging lens assembly provided in an embodiment of this application. As shown in Figure 17, in this embodiment, the imaging lens assembly 40 includes a first imaging lens 410, a second imaging lens 420, a third imaging lens 430, and a fourth imaging lens 440 arranged sequentially along the optical path propagation direction. The first imaging lens 410 is a Fresnel lens, the second imaging lens 420 is a spherical lens, the third imaging lens 430 is a spherical lens, and the fourth imaging lens 440 is a spherical lens. The second imaging lens 420, the third imaging lens 430, and the fourth imaging lens 440 are all spherical lenses, which reduces the design and manufacturing difficulty of the lenses and helps to reduce costs.

[0147] As shown in Figure 17, the first imaging lens 410 is used to form a magnified virtual image of the displayed image (i.e., the first image), and the second imaging lens 420 is used to form a reduced real image of the first image (i.e., the second image). Both the first imaging lens 410 and the second imaging lens 420 can shrink the light beam so that the light beam can be reduced to pass through the aperture S between the second imaging lens 420 and the third imaging lens 430. Both the third imaging lens 430 and the fourth imaging lens 440 can be used to adjust the magnification of the light beam so as to form an image of the required size at a set position. The concave and convex surfaces between the second imaging lens 420, the third imaging lens 430 and the fourth imaging lens 440 cooperate with each other, which helps to reduce aberrations.

[0148] In this embodiment, the parameter ranges of each imaging lens are as follows: the light-incident surface of the first imaging lens 410 is a textured surface, the light-exiting surface is a flat surface, and the distance between the first imaging lens 410 and the liquid crystal display panel 500 is 0-4mm; the light-incident surface of the second imaging lens 420 is a convex surface, the light-exiting surface is a concave surface, the thickness of the second imaging lens 420 on the optical axis is 3mm-4mm, the aperture of the second imaging lens 420 perpendicular to the optical axis is 4mm-5mm, and the distance between the second imaging lens 420 and the first imaging lens 410 on the optical axis is 10mm-13mm; the light-incident surface of the third imaging lens 430 is a concave surface, the light-exiting surface is a flat surface, and the light-exiting surface is a flat surface. The light-incident surface of the third imaging lens 430 is convex, and the thickness of the third imaging lens 430 on the optical axis is 2.5mm to 3.5mm. The aperture of the second imaging lens 420 perpendicular to the optical axis is 3mm to 4mm. The distance between the third imaging lens 430 and the second imaging lens 420 on the optical axis is 8mm to 9mm. The light-incident surface of the fourth imaging lens 440 is concave, and the light-outcident surface is convex. The thickness of the fourth imaging lens 440 on the optical axis is 3mm to 4mm. The aperture of the fourth imaging lens 440 perpendicular to the optical axis is 6mm to 7mm. The distance between the fourth imaging lens 440 and the third imaging lens 430 on the optical axis is 5mm to 6mm.

[0149] Tests have shown that when the imaging lens group 40 provided in this application embodiment is used, the geometric efficiency of light can reach more than 70%. Here, geometric efficiency is defined as the ratio of the luminous flux of the projected image to the total luminous flux emitted by the light source 310. It can be seen that the projected image has high brightness, which is beneficial to improving the contrast and clarity of the projected image.

[0150] In this application, the vehicle headlight projection device may include any one of the above-described lighting components embodiments 1 to 4 and any one of the imaging lens group 400 embodiments 1 to 3. Several possible embodiments are given below.

[0151] Example 1 of vehicle headlight projection device:

[0152] Figure 18 is a schematic diagram of the structure of the optical components in the vehicle headlight projection device provided in the embodiment of this application. Figure 18 can show that the vehicle headlight projection device in the embodiment of this application includes a combination of the lighting component embodiment 2 and the imaging lens group embodiment 1. The optical components in the vehicle headlight lens device include a light source 310 and a first lens 321 (spherical lens), a second lens 322 (spherical lens), a third lens 323 (Fresnel lens), a first substrate 510, a liquid crystal layer 520, a second substrate 530, a first imaging lens 410 (Fresnel lens), a second imaging lens 420 (spherical lens), and a third imaging lens 430 (aspherical lens) arranged sequentially along the light path propagation direction.

[0153] Vehicle headlight projection device embodiment 2:

[0154] Figure 19 is a schematic diagram of the structure of the optical components in the vehicle headlight projection device provided in the embodiment of this application. As shown in Figure 19, the vehicle headlight projection device in the embodiment of this application includes a combination of the lighting component embodiment 2 and the imaging lens group embodiment 2. The optical components in the vehicle headlight lens device include a light source 310 and a first lens 321 (spherical lens), a second lens 322 (spherical lens), a third lens 323 (Fresnel lens), a first substrate 510, a liquid crystal layer 520, a second substrate 530, a first imaging lens 410 (Fresnel lens), a second imaging lens 420 (Fresnel lens), and a third imaging lens 430 (spherical lens) arranged sequentially along the light path propagation direction.

[0155] Vehicle headlight projection device embodiment 3:

[0156] Figure 20 is a schematic diagram of the structure of the optical components in the vehicle headlight projection device provided in the embodiment of this application. As shown in Figure 20, the vehicle headlight projection device in the embodiment of this application includes a combination of the lighting component embodiment 2 and the imaging lens group embodiment 3. The optical components in the vehicle headlight lens device include a light source 310 and a first lens 321 (spherical lens), a second lens 322 (spherical lens), a third lens 323 (Fresnel lens), a liquid crystal display panel 500, a first imaging lens 410 (Fresnel lens), a second imaging lens 420 (spherical lens), and a third imaging lens 430 (aspherical lens) arranged sequentially along the light path propagation direction.

[0157] Example 4 of vehicle headlight projection device:

[0158] Figure 21 is a schematic diagram of the structure of the optical components in the vehicle headlight projection device provided in the embodiment of this application. As shown in Figure 21, the vehicle headlight projection device in the embodiment of this application includes a combination of the lighting component embodiment 3 and the imaging lens group embodiment 1. The optical components in the vehicle headlight lens device include a light source 310 and a first lens 321 (aspherical lens), a second lens 322 (spherical lens), a third lens 323 (Fresnel lens), a first substrate 510, a liquid crystal layer 520, a second substrate 530, a first imaging lens 410 (Fresnel lens), a second imaging lens 420 (spherical lens), and a third imaging lens 430 (aspherical lens) arranged sequentially along the light path propagation direction.

[0159] Example 5 of vehicle headlight projection device:

[0160] Figure 22 is a schematic diagram of the structure of the optical components in the vehicle headlight projection device provided in the embodiment of this application. As shown in Figure 22, the vehicle headlight projection device in the embodiment of this application includes a combination of the lighting component embodiment 3 and the imaging lens group embodiment 3. The optical components in the vehicle headlight lens device include a light source 310 and a first lens 321 (aspherical lens), a second lens 322 (spherical lens), a third lens 323 (Fresnel lens), a first substrate 510, a liquid crystal layer 520, a second substrate 530, a first imaging lens 410 (Fresnel lens), a second imaging lens 420 (spherical lens), a third imaging lens 430 (spherical lens), and a fourth imaging lens 440 (spherical lens) arranged sequentially along the light path propagation direction.

[0161] Pupil diameter, n represents the refractive index of air, and θ represents the emission angle of the light beam emitted by the illumination mirror group 320.

[0162] In traditional projection devices, the aperture number F is typically around 3, which makes the design of the imaging lens group 40 more difficult. Furthermore, a larger F value indicates a smaller entrance pupil diameter for the imaging lens group 40, resulting in less light entering the imaging lens group 40. This application limits the aperture number F to F≥2.0. By reducing the exit angle of the light beam emitted from the illumination lens group 320 and increasing the entrance pupil diameter of the imaging lens group 40, the utilization rate of the light emitted from the light source 310 is improved, thereby increasing the brightness of the projected display. In some embodiments of this application, the aperture number F of the imaging lens group 40 is 1.8 to 2.0. The brightness of the vehicle headlight projection device provided by this application can reach 150 lm.

[0163] Furthermore, in this application, the length of the illumination lens group 320 on the optical axis is less than or equal to 15 mm, the length of the imaging lens group 40 on the optical axis is less than or equal to 30 mm, the length of the liquid crystal display panel 500 on the optical axis is less than or equal to 6 mm, and the total length of the illumination lens group 320, the liquid crystal display panel 500 and the imaging lens group 40 on the optical axis is less than or equal to 54 mm. The optical components in the vehicle headlight projection device provided in this application occupy a small space and can be integrated into a 0.15L space, combining the advantages of high brightness and small size.

[0164] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0165] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A vehicle headlight projection device, wherein, include: The lighting assembly includes a light source and an illumination mirror assembly; The illumination mirror assembly is located on the light-emitting side of the light source; The illumination lens group includes at least a first lens and a second lens arranged sequentially along the optical path propagation direction. Both the first lens and the second lens have positive optical power, and the distance between the first lens and the light source is less than the focal length of the first lens. The display panel, located on the light-emitting side of the illumination mirror group, is used to modulate the light emitted from the illumination mirror group to form a display image; An imaging lens assembly, located on the light-emitting side of the display panel, is used to image the displayed image.

2. The vehicle headlight projection device as described in claim 1, wherein, The light-incident surface of the first lens is either a plane or a convex surface, and the light-exit surface of the first lens is a convex surface; When the light-incident surface of the first lens is convex, the radius of curvature of the light-incident surface of the first lens is greater than the radius of curvature of the light-outceasing surface of the first lens.

3. The vehicle headlight projection device as described in claim 1 or 2, wherein, The light-incident surface of the second lens is either a plane or a convex surface, and the light-exit surface of the second lens is a convex surface; When the incident surface of the second lens is convex, the radius of curvature of the incident surface of the second lens is greater than the radius of curvature of the emitting surface of the first lens.

4. The vehicle headlight projection device as described in claim 1, wherein, The first lens and the second lens are spherical lenses, or the first lens and / or the second lens are aspherical lenses.

5. The vehicle headlight projection device as described in claim 4, wherein, The incident surface of the aspherical lens is a plane, and the exit surface of the aspherical lens is a freeform surface.

6. The vehicle headlight projection device according to any one of claims 1 to 5, wherein, The optical thickness of a lens with a smaller distance from the light source is greater than the optical thickness of a lens with a larger distance from the light source. The optical thickness is the product of the thickness of the lens on the optical axis and the refractive index of the lens.

7. The vehicle headlight projection device as described in claim 6, wherein, The aperture of a lens with a larger distance from the light source in the direction perpendicular to the optical axis is larger than that of a lens with a smaller distance from the light source in the direction perpendicular to the optical axis.

8. The vehicle headlight projection device according to any one of claims 1 to 7, wherein, The distance between two adjacent lenses with a greater distance from the light source on the optical axis is greater than the distance between two adjacent lenses with a smaller distance from the light source on the optical axis.

9. The vehicle headlight projection device according to any one of claims 1 to 8, wherein, The illumination mirror assembly also includes: The third lens is located on the light-emitting side of the second lens, and the third lens is a Fresnel lens.

10. The vehicle headlight projection device as claimed in claim 9, wherein, The distance between the third lens and the second lens on the optical axis is less than or equal to the distance between the second lens and the first lens on the optical axis.

11. The vehicle headlight projection device as described in claim 9 or 10, wherein, The light-incident surface of the third lens is a plane, and the light-exit surface of the third lens is a textured surface.

12. The vehicle headlight projection device according to any one of claims 1 to 11, wherein, The length of the illumination mirror assembly on the optical axis is less than or equal to 15 mm.

13. The vehicle headlight projection device according to any one of claims 1 to 12, wherein, The imaging lens group includes a plurality of imaging lenses arranged sequentially along the optical path propagation direction. The plurality of imaging lenses includes at least one Fresnel lens, which is located on the side of the imaging lens group closer to the display panel.

14. The vehicle headlight projection device as claimed in claim 13, wherein, The imaging lens group includes a first imaging lens, a second imaging lens, and a third imaging lens arranged sequentially along the optical path propagation direction; the first imaging lens is a Fresnel lens, the second imaging lens is a spherical lens, and the third imaging lens is an aspherical lens.

15. The vehicle headlight projection device as claimed in claim 14, wherein, The first imaging lens has a textured light-incident surface and a planar light-outcident surface; the second imaging lens has a convex light-incident surface and a concave light-outcident surface; the third imaging lens has a concave light-incident surface and a convex light-outcident surface.

16. The vehicle headlight projection device as claimed in claim 13, wherein, The imaging lens group includes a first imaging lens, a second imaging lens, and a third imaging lens arranged sequentially along the optical path propagation direction. The first imaging lens is a Fresnel lens, the second imaging lens is a Fresnel lens, and the third imaging lens is a spherical lens.

17. The vehicle headlight projection device as claimed in claim 16, wherein, The first imaging lens has a textured light-incident surface and a planar light-outcident surface; the second imaging lens has a textured light-incident surface and a planar light-outcident surface; the third imaging lens has a concave light-incident surface and a convex light-outcident surface.

18. The vehicle headlight projection device as claimed in claim 13, wherein, The imaging lens group includes a first imaging lens, a second imaging lens, a third imaging lens, and a fourth imaging lens arranged sequentially along the optical path propagation direction. The first imaging lens is a Fresnel lens, the second imaging lens is a spherical lens, the third imaging lens is a spherical lens, and the fourth imaging lens is a spherical lens.

19. The vehicle headlight projection device as claimed in claim 18, wherein, The first imaging lens has a textured light-incident surface and a planar light-outcident surface; the second imaging lens has a convex light-incident surface and a concave light-outcident surface; the third imaging lens has a concave light-incident surface and a convex light-outcident surface; the fourth imaging lens has a concave light-incident surface and a convex light-outcident surface.

20. The vehicle headlight projection device according to any one of claims 14 to 19, wherein, The focal length of the first imaging lens is less than or equal to 35mm, and the length of the imaging lens group on the optical axis is less than or equal to 30mm.

21. The vehicle headlight projection device according to any one of claims 1 to 20, wherein, The illumination lens group and the imaging lens group satisfy the following relationship: Wherein, F represents the aperture number of the imaging lens group, F≤2.0, f represents the focal length of the imaging lens group, D represents the entrance pupil diameter of the imaging lens group, n represents the refractive index of air, and θ represents the emission angle of the light beam emitted by the illumination lens group.

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