Light guide for a vehicle light assembly

Abstract

A vehicle lamp has a light guide (1) that emits a light blade. The light guide has two opposing large walls (7, 8), an elongated thin light-emitting surface (10), a reflective surface (11) opposite to the light-emitting surface (10), and multiple coupling points (4) on one of the walls for accommodating the light source. Multiple collimators (14) are provided at the coupling points (4) for collecting the light emitted by the light source and guiding the collimated beam to the reflective surface (11). The reflective surface (11) is configured to converge the reflected light into a focusing region (15) located upstream of the light-emitting surface (10).

Description

Technical Field

[0001] This invention relates to the field of automotive lighting, and more particularly to a lamp that produces a light blade effect. Background Technology

[0002] EP3486558 discloses a light blade composed of a planar light guide, which is illuminated by a light source. Because the light source is too bulky compared to the thickness of the light blade, it is positioned at one end of the light guide, on its side wall, and the light guide has a reflective surface that forms an angle to reflect light from inside the light guide to its other end. The light travels within the light guide via total internal reflection, and some light rays decouple before reaching the front of the light guide. Therefore, its optical efficiency needs improvement.

[0003] Technical issues

[0004] The present invention aims to solve the optical efficiency problem of light blades containing planar light guides with side-mounted light sources, especially when the thickness of the light blade is extremely small (e.g., 2 mm or less).

[0005] In this specification, a "planar" shape means that the dimension of the first dimension (thickness) of the shape is less than 50% of the dimension of any other dimension (depth or width) of the shape. Summary of the Invention

[0006] One object of the present invention is to provide a light guide for an automotive lighting assembly, the light guide having two opposing large walls, an elongated thin light-emitting surface, a reflective surface opposite to the light-emitting surface, and a plurality of coupling points on one of the walls for accommodating a light source, characterized in that the light guide further comprises a plurality of collimators at the coupling points, each collimator being configured to collect light emitted by the light source and guide the collimated beam to the reflective surface, and the reflective surface being configured to focus the reflected light in a focusing region located upstream of the light-emitting surface.

[0007] In this specification, a collimator is an optical device primarily used to control the direction of light rays so that they are emitted as parallel beams.

[0008] In this specification, the “focus area”, or “focal spot area”, refers to the limited area where most of the light beams from the reflecting surface converge.

[0009] In the light guide of the present invention, the remaining path of light from the focusing area to the light emitting surface is used to achieve defocusing of the light so as to avoid light spots appearing on the light emitting surface.

[0010] Thanks to this invention, focusing the light upstream of the front end reduces light loss as it passes through the two opposing large walls of the light guide.

[0011] This invention defines a relatively thin light guide. In the context of this invention, a relatively thin object refers to an object whose thickness is relatively small compared to its other dimensions (such as length, width, or depth). The word "relatively" is used to indicate that the object or material is not extremely thin, but is still thinner than the average or expected thickness. For example, a sheet of paper that is not as thick as cardboard—though thicker than some other types of paper—can still be called "relatively thin." In one embodiment, the invention aims to achieve a light-emitting surface thickness of 2 millimeters or even less. However, the overall thickness of the light guide is greater than the thickness of the light-emitting surface, especially at its reflective surface and coupling points, but it is still relatively thin overall. Sometimes the adjective "planar" is used instead of "thin" to describe a relatively thin object, although this is strictly speaking inappropriate, as a planar shape is mathematically a two-dimensional object.

[0012] According to the invention, the reflective surface reflects light collected from each light source and collimated by a collimator. The reflective surface has a parabolic cross section, such that the collimated rays are focused onto a line formed by the focal stretch of the parabolic cross section.

[0013] This technical solution also has the following advantages:

[0014] According to a preferred embodiment, the light guide is extruded along a direction parallel to the light-emitting surface, and the reflective surface has a parabolic cross-section, with its focal point located in the focusing region. The extrusion molding process simplifies the manufacturing of the light guide.

[0015] Furthermore, the parabolic profile helps to collect as much light as possible. Therefore, despite the small thickness of the light blade, less light escapes from the sidewalls of the light guide.

[0016] According to a preferred embodiment, the coupling sites form adjacent dome structures, each dome structure having a hollow receiving seat surrounded by parabolic walls facing the reflective surface. This embodiment achieves more efficient illumination by highly integrating the light source into the light guide body.

[0017] According to a preferred embodiment, the portion of the planar light guide located between the focusing region and the light-emitting surface has a constant thickness, and two relatively large walls are parallel to each other at this portion. Therefore, a thin portion with parallel walls can be inserted into the light-blade opening in the front panel.

[0018] According to a preferred embodiment, the thickness of the light guide gradually decreases between the reflective surface and the focusing area.

[0019] According to a preferred embodiment, the reflective surface is provided with optical devices for homogenizing the reflected light beam, such as ribs or cushion structures, so that the light emanating from the light-emitting surface is uniform and there are no light spots indicating the presence of a single light source.

[0020] To further improve the uniformity of light emission from the surface, at least one wall surface can be macro-textured. For this purpose, the standard and well-known surface texturing process VDI27 can be used. Specifically, the surface emission surface can be grained.

[0021] Another object of the present invention is to provide a vehicle lighting assembly comprising at least one of the above-described light guides. Attached Figure Description

[0022] A better understanding of the invention will be achieved by reading the following description, which is provided by way of example only. The terms "top," "bottom," "front," and "rear" refer to the orientation of the vehicle lights when they are mounted on the vehicle and in their conventional upright position. The following description refers to the accompanying drawings, in which:

[0023] [Figure 1] is a perspective view of a planar light guide according to an embodiment of the present invention.

[0024] [Figure 2] is along Figure 3 Sectional view of line II-II in the middle.

[0025] [Figure 3] is Figure 1 The top view of the light guide shown. Detailed Implementation

[0026] The light guide 1 is relatively thin, which means that if the light guide is housed in a parallelepiped shape, the thickness t0 of the shape is less than 50% of either its length l or width w.

[0027] In this embodiment, the light guide is curved to fit the shape of the vehicle body (not shown). This curvature is an aesthetic design choice and does not change the definition of the light guide as a thinner light guide. For simplicity, the light guide can be considered equivalent to a light guide with a rectangular shape (i.e., with straight sides 2 and 3 rather than curved sides).

[0028] Edges 2 and 3 are the front edge 2 and the back edge 3, respectively. In the example, edges 2 and 3 are curved, but curvature is not a necessary condition.

[0029] The light guide 1 has multiple dome structures 4 along its rear side 3. The dome structures 4 constitute coupling points for a light source to provide light to the light guide 1.

[0030] The light guide 1 has two sidewalls 5 and 6, as well as a large top wall 7 and a large bottom wall 8. The dimensions of the large walls 7 and 8 are approximately a width w = 25 cm and a length l = 45 cm. The maximum total thickness t0 of this planar light guide is 4 cm at its thickest part (i.e., the top of the dome structure 4) and 2 cm at the bottom of the dome structure 4. In other words, excluding the dome structure 4, the net thickness t of the light guide is... n It is less than 25% of its width w.

[0031] The light guide 1 has a trapezoidal cross-section, meaning that its large wall surfaces 7 and 8 are not parallel to each other on most of its surface. Only the flange 9 of the light guide 1 is flat, and its thickness is constant at 2 mm.

[0032] The flange 9 terminates at the front edge 2, forming a light-emitting surface 10 with a height of 2 mm. At the rear edge 3 opposite to the light-emitting surface 10, the light guide 1 has a reflective surface 11 extending substantially parallel to the light-emitting surface 10. The reflective surface 11 has a parabolic cross-sectional shape 12, although it is not a parabola. It is a ruled surface whose generatrix is ​​a parabolic curve 12 sliding along a curved path substantially parallel to the light-emitting surface 10.

[0033] Each dome structure 4 on the large top wall 7 is used to house a light source, and the dome structure 4 has an opening 13 forming a receiving seat. The details of the receiving seat are of conventional design. Each opening 13 is surrounded by a partial parabolic wall 14 with the central axis of the opening as its axis (i.e., the downward direction shown in the figure). With the help of the partial parabolic wall 14 of the dome structure 4, any light emitted by the light source (not shown) located in the receiving seat 13 is collimated and forms a parallel beam that is guided downward to the reflecting surface 11, as indicated by the vertical arrow. Therefore, each parabolic wall 14 constitutes an optical collimator.

[0034] The mathematical properties of the parabolic curve 12 enable the reflecting surface 11 to converge the reflected light rays toward the light-emitting surface 10 at a position 15 between the flat flange 9 and the trapezoidal portion of the light guide 1. This position 15 contains a focal point of the parabolic curve 12 and is referred to as the focusing region.

[0035] By utilizing the ruled shape of the reflective surface 11 and the arrangement of the dome structures 4, the light rays collimated by the dome structures 4 are all directed and converged into the focusing area 15. Figure 2 In the cross-sectional view, the focal area appears as a point or a sphere. However, the observer should imagine the volume of the light guide unfolding along a path parallel to the light-emitting surface 10 (e.g., Figure 3 As shown): In this unfolded volume, the focusing region 15 is a line or a longitudinal volume located upstream of and parallel to the front light-emitting surface 10.

[0036] In practice, the light guide 1 can be manufactured using an extrusion molding process, for example, using polymethyl methacrylate (PMMA) material. Therefore, the manufacturing process matches the mathematical description, since the shape of the light guide is defined by its cross-section.

[0037] The convergence of light in the focusing area 15 helps reduce light detachment along the large walls 7 and 8 of the light guide, thereby improving the optical efficiency of the light guide. In the flange 9, the light is de-focalized to ensure uniform diffusion of the light at the light-emitting surface 10, without creating a spot that shows a single light source.

[0038] Granulation treatment of the light-emitting surface 10 and / or the wall surfaces 7 and 8 can improve the distribution of diffuse light.

[0039] like Figure 3 As shown in the top view, the reflecting surface 11 can be divided into rectangular optical devices to homogenize the reflected light beam. The optical device can be a pincushion structure 16. The light reflected by the pincushion structure 16 will be diffused, thereby improving the uniformity of the light at the front light-emitting surface 10.

[0040] List of reference numerals

[0041] 1: Light guide component

[0042] 2, 3: Straight edge

[0043] 4: Dome structure

[0044] 5, 6: Relative large sidewalls

[0045] 7: Top wall surface

[0046] 8: Bottom wall surface

[0047] 9: Flange

[0048] 10: Light-emitting surface

[0049] 11: Reflective surface

[0050] 12: Parabolic Curve

[0051] 13: Kong

[0052] 14: Parabolic wall

[0053] 15: Focus Area

[0054] 16: Pillow-shaped structure

Claims

1. A light guide (1) for an automotive lighting assembly, the light guide having two opposing large walls (7, 8), an elongated thin light-emitting surface (10), a reflective surface (11) opposite to the light-emitting surface (10), and a plurality of coupling points (4) located on one of the walls for accommodating a light source, characterized in that, The light guide also includes a plurality of collimators (14) at the coupling point (4), each collimator (14) being configured to collect light emitted by the light source and guide the collimated beam to the reflective surface (11), and the reflective surface (11) being configured to converge the reflected light into a focusing region (15) located upstream of the light-emitting surface (10).

2. The light guide component according to claim 1, characterized in that, The light guide is extruded in a direction parallel to the light-emitting surface (10), and the reflective surface (11) has a parabolic cross section with its focal point located in the focusing area (15).

3. The light guide element according to any one of the preceding claims, characterized in that, The coupling sites form adjacent dome structures (4), each dome structure (4) having a hollow accommodating seat (13) surrounded by a parabolic wall (14) facing the reflecting surface (11).

4. The light guide element according to any one of the preceding claims, characterized in that, The planar light guide has a constant thickness in the portion between the focusing area (15) and the light-emitting surface (10), and in this portion, the two relatively large wall surfaces (7, 8) are parallel to each other.

5. The light guide according to any one of the preceding claims, characterized in that, The thickness of the light guide gradually decreases between the reflective surface (11) and the focusing area (15).

6. The light guide according to any one of the preceding claims, characterized in that, The reflective surface (11) is provided with an optical device (16) for homogenizing the reflected beam, such as a prism or pincushion structure, so that the light from the light-emitting surface is uniform and there are no light spots indicating the presence of a single light source.

7. The light guide according to any one of the preceding claims, characterized in that, The light-emitting surface (10) is textured.

8. The light guide according to any one of the preceding claims, characterized in that, The thickness of the light-emitting surface (10) is 2 mm or less.

9. A vehicle light, comprising at least one light guide (1) according to any one of the preceding claims.

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