CN1763423A - Light-emitting diode modules for automotive headlights - Google Patents

Abstract

A light gathering module (10) has a body (12) with a first end (14) comprising a single light transmitting surface (16) and a second end (18) having a plurality of arms (20), each arm (20) having an independent light gathering terminus (22) that is rectangular. In a preferred embodiment of the invention, the first end (14) of the body also is rectangular. The light gathering module (10) can be fabricated from acrylic, plastic, glass or other suitable material and preferably has no cladding so that light output is maximized. When combined in a housing (32) with a projector lens (34) the light gathering module (10) provides a vehicle headlamp (30).

Description

Light-emitting diode modules for automotive headlights Cross-reference to related applications

This application claims priority to Provisional Patent Application Serial No. 60/620,933, filed October 21, 2004.

technical field

The present invention relates to an automotive headlight, and in particular to a light emitting diode (hereinafter referred to as LED or LEDS) for such a headlight. It further relates to a headlight using a plurality of light emitting diodes to emulate a point light source and using the light source with eg a projector lens.

Background technique

LED light sources are used in automotive applications due to their long lifetime and excellent durability. Currently, these applications are limited to brake lights, tail lights and interior lighting. Recently invented LEDs that emit white light can also be used in headlights. For example, US Patent No. 6,406,172 teaches an invention of arranging a plurality of LEDs emitting red, green, and blue light in a matrix and mixing these to emit a white light. The light output can also be varied by computer control and can accommodate changes in the orientation of the vehicle with which it is used.

The newer white light-emitting diodes use blue and ultraviolet light-emitting diode light sources combined with yellow-emitting fluorescent (phosphor) phosphors, which mix the output to emit white light.

Recently proposed lamps comprise: a housing with a cap having an annular wall arranged around a longitudinal axis; a hollow body protruding from the caps arranged symmetrically with respect to the longitudinal axis; having a single output end arranged along the longitudinal axis and having a plurality of light guides of radially extending arms, each arm having an input; and a likewise plurality of light emitting diodes operably positioned relative to the radially extending arms. In an embodiment of the inventive light-emitting diode the light-emitting diodes are arranged around the annular wall. The inventive method is described in Provisional Patent Application Serial No. 60/612,080, filed September 22,2004. Although offering a viable solution, light guiding arms typically only include a single light emitting diode. It would therefore be an improvement to provide light collecting modules, and lamps employing light collecting modules, where each arm of the module includes multiple light emitting diodes, thereby increasing light output while reducing the number of optical elements required.

Contents of the invention

It is therefore an object of the present invention to avoid the disadvantages of the prior art.

Another object of the present invention is to provide a light guide or light collection module including a plurality of light emitting diodes.

Another object of the present invention is to provide a standard LED light source with a defined light-emitting surface independent of the number of LEDs.

An aspect of the present invention achieves these objects by providing a light collection module comprising a unitary body having: a first end comprising a single light transmissive surface; and a second end having a plurality of arms , each arm has an independent rectangular light-collecting terminal. The purpose of the rectangular ends of the walls is to allow each arm to collect light from multiple LEDs.

Another aspect of the present invention further achieves these objects by means of an automobile headlight comprising: a housing; a lens located at the front of the housing; and a light collecting module as described above located inside the housing. A first end of the module is operatively associated with the lens. The assembly is small and compact, providing an efficient light source for the headlights.

Description of drawings

1 is a perspective view of an embodiment of a light collection module according to an aspect of the present invention;

Fig. 2 is the perspective view that can be used in the LED housing of the present invention;

Fig. 3 is a partial cross-sectional view of the light-emitting diode housing and the light-collecting module arm;

Figure 4 is a schematic diagram of a car headlight; and

Figure 5 is an end view of a light emitting diode housing illustrating some of the desired relationships.

Detailed ways

For a better understanding of the present invention, the following and the appended claims are described with reference to advantages and properties in connection with other and expected objects in conjunction with the above-mentioned drawings.

Now specifically referring to the accompanying drawings, as shown in FIG. part 18, each arm 20 has an independent rectangular light-collecting terminal 22. In a preferred embodiment of the invention the first end 14 of the body is also rectangular. The light collection module 10 can be made of acrylic, plastic, glass or other suitable material and is preferably uncoated to maximize light output. Since the light collecting device 10 is made of a single piece, it is not necessary to arrange a large number of individual optical fibers.

The LEDs 24 are located in a housing 35 associated with each terminal 22 . As shown in Fig. 2 and Fig. 3, a plurality of light-emitting diodes can be individually packaged as a unit, or it can be packaged independently with a plurality of chips. The space occupied by the LEDs can be controlled by placing the wire-bonded LEDs sideways. Further, the light emitting diode can be directly provided on a printed circuit board such as ceramic or metal as the core. In a preferred embodiment of the present invention, each diode chip is a square with a side length of 1 mm as shown in Figure 5 "C", and five chips are arranged in a longitudinal direction with a length of 5.4 mm. Preferably, the distance between the chips is 100 um (microns). The light guide arm has a length "L" of 6 to 7 mm and a width "W" of about 2 mm. Of course, the housing 35 can accommodate approximately five chips if desired.

The housing 35 is preferably placed on a heat transfer ceramic 37 which in turn is placed on a heat sink, which may be made of aluminum or copper.

Optical encapsulant 38 is disposed between walls 40 of housing 35 and protrudes a length "D" beyond the surface of the LED. In order to ensure good optical coupling, "D" should be smaller than "W".

The automotive headlight 30 comprises: the light collecting device 10 as schematically shown in FIG. 4 ; and a housing 32 having a lens 34 located on a front portion 44 . Preferably, the lens 34 is a projection lens. The light collection module 10 is located in the housing 32 and the first end 14 is operatively associated with the lens 34 . Preferably, the output of module 12 is located close to the focal point of lens 34 .

Light-emitting diodes used in headlights or rear lights preferably emit white light, such as conventional surface-emitting light-emitting diodes that use phosphors. However, other colors may also be used.

Electrical connections (not shown) to the LEDs may be formed by any suitable method including via a printed circuit board. The size and thermal capacity of the heat sink is determined by several factors, including the efficacy of the LED and the amount of power required to drive the LED.

Therefore, there is provided a headlight for a vehicle which can be manufactured economically and which has a high light collecting ability due to the configuration of the light collecting module.

While pointing out and describing the preferred embodiments of the present invention, changes and modifications in the art are evident without departing from the scope of the present invention as defined in the appended claims.

Claims (8)

1. light-collecting module comprises:

Monolithic entity has: the first end that comprises single light transmitting surface; And

The second end with a plurality of arms, each arm have independently rectangular light harvesting terminal.

2. light-collecting module according to claim 1, the described first end of wherein said body is a rectangle.

3. light-collecting module according to claim 2, wherein a plurality of light emitting diodes and each terminal associated.

4. automobile headlamp comprises:

Housing;

Be positioned at the lens of described housing front portion;

Be positioned at the light-collecting module of described housing, comprise:

Body, described body has: the first end that comprises single light transmitting surface; And have the second end of a plurality of arms, and each arm has independently rectangular light harvesting terminal, and described first end and described lens are associated operationally.

5. automobile headlamp according to claim 4, the described first end of wherein said body is rectangular.

6. automobile headlamp according to claim 5, wherein a plurality of light emitting diodes and each terminal associated.

7. automobile headlamp according to claim 5, wherein said lens are projection lens.

8. automobile headlamp according to claim 7, wherein said light emitting diode is set in the housing, and described housing is set on the heat abstractor.

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