A compact projection type LED headlight

Abstract

The present invention belongs to the technical field of LED lighting, and discloses a compact projection-type LED headlight, comprising an LED light source, a TIR lens, and a light shape conversion plate. The light shape conversion plate is divided into three areas, one area being a cylindrical lens array area, and the other two areas being wedge plate areas. Three LEDs are collimated by three TIR lenses respectively, and then incident on three areas on the light shape conversion plate respectively. The light incident on the cylindrical lens array area generates a strip-shaped light spot with uniform illumination distribution on the target surface after passing through the cylindrical lens array, and the two parts of light incident on the wedge plate area are deflected by the wedge plate and incident on the designated area to form a bright spot. The superposition of these three parts of light on the target surface can produce light that meets the requirements of automobile low beam lighting. This headlight adopts a projection method, and uses a light shape conversion plate to achieve the illumination requirements of the low beam of the headlight, and does not use any shading plate. Therefore, compared with traditional automobile low beam lights, it has high efficiency and compact structure.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile lighting, relates to a technology for distributing light to an LED light source, and specifically relates to a compact, projection-type LED automobile lamp. Background Art

[0002] LED is gradually replacing halogen lamps due to its advantages of energy saving, environmental protection, long service life, etc., and is widely used in automotive lighting. However, most of the current LED headlights adopt a reflective structure, which is large in size, and in order to meet the regulatory requirements of automotive lighting and produce a clear cut-off line, a shading plate is often required, which will block part of the light and reduce the light efficiency of the LED headlight. In order to overcome this shortcoming, the present invention proposes a projection-type LED headlight, which has the advantages of high efficiency and compact structure. Summary of the invention

[0003] In view of the fact that the existing reflective LED headlights have a relatively large structure and require a visor to block a large part of the light, and have a relatively low light efficiency, the present invention uses a projective optical system to achieve light distribution for the LED light source, which not only meets the requirements of automobile lighting regulations, but also overcomes the shortcomings of the existing reflective headlights, which have a relatively large structure and relatively low efficiency.

[0004] The technical solution adopted by the present invention is: a compact projection-type LED headlight, comprising at least one LED headlight unit, wherein one LED headlight unit comprises three LED light sources, three TIR lenses respectively combined with the three LED light sources, and a light shape conversion plate. The light shape conversion plate is arranged in front of the TIR lens, and three light shape conversion areas are arranged on the light shape conversion plate, and the three light shape conversion areas include a cylindrical lens array area and two wedge plate areas. After passing through the TIR lens, the light emitted by each LED becomes a collimated light beam, that is, a light beam with a divergence angle of almost zero. The collimated light beams emitted through the three TIR lenses are respectively incident on the three light shape conversion areas on the light shape conversion plate, and the light refracted through the three light shape conversion areas is irradiated onto the target surface together, generating a light shape distribution on the target surface that meets the requirements of the low beam lighting of the car.

[0005] The TIR lens is a rotationally symmetrical structure, so a lens profile can be designed first, such as Figure 2 As shown, around Figure 2The rotation axis represented by the dotted line rotates 360 degrees to form a solid lens. The TIR lens is a rotationally symmetric structure, so the function of the TIR lens can be analyzed by analyzing the propagation of light in the lens contour. The contour of the TIR lens mainly includes four parts, namely the S1 surface, the S2 surface, the S3 surface, and the S4 surface. The S3 surface is the inner surface of the lens, which is a spherical surface, the S2 surface is the plane exit surface, and the S1 surface and the S4 surface are the free-form surface transmission surface and the free-form surface reflection surface, respectively. The LED light source is placed at the center of the spherical surface S3. When the LED light source passes through the inner surface of this spherical surface, the light does not change. The light emitted by the light source passes through the S3 surface and then enters the S1 surface. After passing through the S1 surface, it becomes a light parallel to the rotation axis. The light emitted through the S1 surface is the transmission area. The light emitted by the light source passes through the S3 surface and then enters the S4 surface. It is totally reflected on the S4 surface and then passes through the S2 surface and becomes a light parallel to the rotation axis. The area where the reflection occurs on the S4 surface is the reflection area. The angle range of the transmission area is generally 0-45 degrees, and the reflection area is 45-88 degrees.

[0006] The light shape conversion plate comprises a plurality of cylindrical lens array regions and wedge-shaped plate regions. The cylindrical lens array regions and wedge-shaped plate regions are configured in a ratio of 1:2, for example, one cylindrical lens array region is equipped with two wedge-shaped plate regions.

[0007] The cylindrical lens array is composed of multiple cylindrical lenses arranged along the radial direction. The cross-section of the cylindrical lens is a hemispherical surface. The collimated light first converges and then diverges after passing through each cylindrical lens to hit the target surface. Each small light beam first converges and then diverges after passing through a cylindrical lens, and can be extended to a large area on the target surface. The target surface is 25 meters away from the LED headlights. In this way, each light beam incident on multiple cylindrical lenses generates multiple light beams after being emitted, which produce uniform illumination distribution after being superimposed on the target surface. The radius R of the cylindrical lens varies in the range of 1-4mm, and the size of the cylindrical lens array area (XY plane) must be able to cover the area of ​​the light emitted from the TIR lens.

[0008] The cross-sectional profile (XZ plane) of the wedge plate is a trapezoid, and the wedge angle of the wedge plate varies from 5 to 30 degrees. The size of each wedge plate area (XY plane) must be able to cover the area of ​​light emitted from the TIR lens. The wedge plate is mainly used to deflect the light beam so that the bright spot on the target surface deviates from the center, because the lighting requirements of the car low beam headlights require that the bright spot cannot be located in the center area.

[0009] The compact, high-light-efficiency, projection-type LED headlight proposed by the present invention uses three LED light sources in one LED headlight unit. The light of the first LED light source is collimated by a TIR lens and passes through a cylindrical lens array area to form a strip-shaped light spot with uniform illumination distribution on the target surface. The light of the second LED light source is collimated by a TIR lens and deflected after passing through a wedge plate area, and can be incident on a designated area on the target surface to produce a bright spot. The light of the third LED light source is collimated by a TIR lens and deflected after passing through another wedge plate area, and is superimposed with the bright spot generated by the third LED in the target area. In this way, the light spot finally generated by the three LED light sources on the target surface can meet the illumination distribution and light shape requirements of the automobile low beam. This headlight adopts a projection method and uses a light shape conversion plate to achieve the illumination requirements of the low beam of the headlight. No shading plate is used. Therefore, compared with traditional automobile low beams, it has high efficiency and compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural diagram of the compact projection-type LED car light optical system of the present invention.

[0011] Figure 2 It is a schematic diagram of the TIR lens outline structure.

[0012] Figure 3 It is a schematic diagram of the optical principle of the cylindrical lens array.

[0013] Figure 4 is a schematic diagram of the optical principle of the wedge plate.

[0014] FIG. 5 is a diagram showing the illumination distribution effect of the compact projection-type LED vehicle lamp of the present invention. DETAILED DESCRIPTION

[0015] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0016] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0017] In the description of the present invention, the terms “first”, “second”, “third”, etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0018] The specific implementation of the present invention is as follows: The structural features and feasibility of the compact projection-type LED vehicle lamp of the present invention are further explained below in conjunction with the accompanying drawings.

[0019] The structure diagram of the compact projection type LED car light optical system of the present invention is as follows Figure 1 As shown, the compact projection-type LED car light optical system includes an LED light source 5, a TIR lens 4, and a light shape conversion plate. Each LED light source is placed at the center of the sphere on the inner surface of the corresponding TIR lens. After passing through the TIR lens, the light emitted by each LED becomes a collimated light beam, that is, the divergence angle is almost zero. The collimated light beam emitted through the TIR lens is respectively incident on the corresponding light shape conversion areas 1, 2, and 3 on the light shape conversion plate. After passing through the three areas, the light is incident on the target surface, generating a light shape distribution on the target surface that meets the requirements of the car's low beam lighting.

[0020] The TIR lens is a rotationally symmetrical structure, so a lens profile can be designed first, such as Figure 2 As shown, around Figure 2 The rotation axis represented by the dotted line rotates 360 degrees to form a solid lens. The TIR lens is a rotationally symmetric structure, so the function of the TIR lens can be analyzed by analyzing the propagation of light in the lens contour. The contour of the TIR lens mainly includes four parts, S1 surface, S2 surface, S3 surface, and S4 surface. Among them, S3 is the inner surface of the lens, which is a spherical surface. The LED light source is placed on the center of the spherical surface S3. The LED light source passes through the inner surface of the spherical surface, and the light does not change. The light emitted by the light source is emitted through the S3 surface and then incident on the surface S1. After being emitted from the S1 surface, it becomes a light parallel to the direction of the rotation axis. The light area emitted from the surface S1 is defined as the transmission area. The light emitted by the light source is emitted through the S3 surface and then incident on the surface S4. Total reflection occurs on the S4 surface. After being emitted from the S2 surface, it becomes a light parallel to the direction of the rotation axis. The light in the area where total reflection occurs on the S4 surface is defined as the reflection area. The angle range of the transmission area is generally 0-45 degrees, and the angle range of the reflection area is 45-88 degrees. Both the S1 surface and the S4 surface are free-form surfaces.

[0021] The light shape conversion plate is divided into three light shape conversion areas, namely, cylindrical lens array area 1, first wedge plate area 2, and second wedge plate area 3. The cylindrical lens array area and the wedge plate area are configured in a 1:2 ratio, such as one cylindrical lens array area is equipped with two wedge plate areas. The number of areas divided by the light shape conversion plate should be consistent with the number of LEDs and the number of TIR lenses.

[0022] The cylindrical lens array is composed of multiple cylindrical lenses arranged along the radial direction. The cross-section of the cylindrical lens is a hemispherical surface. The collimated light first converges and then diverges after passing through each cylindrical lens to hit the target surface. Each small light beam first converges and then diverges after passing through a cylindrical lens, and can be extended to a large area on the target surface. The target surface is 25 meters away from the LED headlights. In this way, each light beam incident on multiple cylindrical lenses generates multiple light beams after being emitted, which produce uniform illumination distribution after being superimposed on the target surface. The radius R of the cylindrical lens varies in the range of 1-4mm, and the size of the cylindrical lens array area (XY plane) must be able to cover the area of ​​the light emitted from the TIR lens.

[0023] The wedge plate is mainly used to deflect the light beam, so that the bright spot on the target surface is off-center, because the lighting requirements of the car low beam headlights require that the bright spot cannot be located in the central area. The cross-sectional profile (XZ plane) of the wedge plate is a trapezoid, and the wedge angle α of the wedge plate varies from 5 to 30 degrees. The size of each wedge plate area (XY plane) must be able to cover the area of ​​light emitted from the TIR lens.

[0024] Reference Figure 5 In this example, there are three groups of LEDs. After the first LED is collimated by the TIR lens, it passes through the cylindrical lens array to form a strip light spot A with uniform illumination distribution on the target surface. After the second LED is collimated by the TIR lens, it is deflected after passing through the wedge plate and can be incident on the specified area on the target surface to produce a bright spot. After the third LED is collimated by the TIR lens, it is deflected after passing through the wedge plate and superimposed with the bright spot generated by the second LED in the target area to produce a uniform bright spot B on the target surface. The illumination distribution diagram generated by this compact, projected LED headlight is shown in Figure 1. Figure 5 shown.

[0025] If the number of LEDs needs to be increased, the number of increases is usually a multiple of 3, such as the number of LEDs can be increased to 6, 9, etc. The number of TIR lenses remains the same as the number of LEDs, the number of areas divided by the light shape conversion plate must also be the same as the number of LEDs, and the number of areas of the cylindrical lens array in the light shape conversion plate and the number of areas of the wedge plate must be maintained at 1:2.

Claims

1. A compact projection-type LED headlight, comprising at least one LED headlight unit, characterized in that: An LED headlight unit includes three LED light sources, three TIR lenses respectively combined with the three LED light sources, and a light shape conversion plate, wherein the light shape conversion plate is arranged in front of the TIR lens, and three light shape conversion areas are arranged on the light shape conversion plate, wherein the three light shape conversion areas include a cylindrical lens array area and two wedge plate areas; light emitted by the three LED light sources passes through the TIR lens as collimated light beams and is incident on the three light shape conversion areas on the light shape conversion plate respectively, and the light refracted by the three light shape conversion areas is irradiated onto a target surface together, thereby generating a light shape distribution on the target surface that meets the requirements of the low beam lighting of the vehicle; The TIR lens comprises an inner surface, a free-form surface transmission surface, a free-form surface reflection surface, and a plane output surface, wherein the inner surface is a spherical surface, and the LED light source is placed at the center of the sphere of the inner surface. The light emitted by the LED in a small angle area becomes a collimated light beam after being emitted through the free-form surface transmission surface, and the light in a large angle area is reflected by the free-form surface reflection surface area and then emitted through a plane output surface, and becomes a collimated light beam after being emitted. The transmission light angle area generally ranges from 0 to 45 degrees, and the reflection light angle area ranges from 45 to 88 degrees. It comprises a plurality of LED lamp units, wherein the light shape changing plate comprises a plurality of cylindrical lens array areas and wedge-shaped plate areas, and the ratio of the number of the cylindrical lens array areas to the number of the wedge-shaped plate areas is 1:

2.

2. The compact, projector-type LED vehicle lamp according to claim 1, characterized in that: The cylindrical lens array is composed of multiple cylindrical lenses arranged along the radial direction. The cross section of the cylindrical lens is a hemispherical surface. The radius (R) of the cylindrical lens varies from 1 to 4 mm. The cylindrical lens array area covers the light emitted by the corresponding TIR lens.

3. The compact projection-type LED vehicle lamp according to claim 1, characterized in that: The cross-sectional profile of the wedge plate is a trapezoid, and the wedge angle of the wedge plate varies in the range of 5-30 degrees. Each wedge plate area covers a corresponding light emitted by the TIR lens.

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