AU2004272122B2 - A variable focus driving light - Google Patents

Description

A VARIABLE FOCUS DRIVING LIGHT FIELD FIELD The present invention relates to a driving light for producing spreadable light beams for use in driving. 5 BACKGROUND Currently, driving lights provide lighting by the use of separate lights with a fixed beam width which may be focused on a particular point. A second wider light may be required, to illuminate a larger unlit area. In order to provide high beam and low beam for instance, two filaments are provided in the one light. One filament, located at the 10 focus point of a light provides a maximum light well ahead of the car being a high beam, while the other, positioned below the first, provides a dipped beam which is shorter and lower, being the low beam. Additionally flood lights, spotlights and other lights may be attached to the car to allow for varying lighting requirements. Limitations on the light construction tend to 15 restrict each light to produce limited beams. Thus in order to achieve different beams, additional lights may be required. This creates wasted light in the vertical plane which is not required for improved driver vision, thereby wasting power. Further, the use of numerous lights increases the power consumption of the lighting. It would be useful to provide a light that produces a variable focus light beam. 20 STATEMENT OF INVENTION According to a first broad form of the invention, there is provided a driving light including: a light source; 25 an internal reflective surface positioned relative to the light source; and a housing to contain the light source and the internal reflective surface; wherein the internal reflective surface comprises at least one elliptical horizontally disposed portion that extends across the internal reflective surface and is arranged to be translated in a horizontal plane relative to the reflective surface. 30 Preferably the horizontally disposed portion is moved backwards and WO 2005/025934 PCT/AU2004/001235 2 forwards relative to the light source. In a second embodiment, preferably the horizontally disposed portion is also moved longitudinally. The light source is preferably located at or near the focal point of the 5 internal reflective surface so that the rays traveling behind the focal point reflect from the internal reflective surface, including the horizontally disposed portion, to form a beam of light of wider or narrower spread. By displacing the horizontally disposed portion, the focus of the light may be adjusted so that the light beam forms a range of beams from a spot beam to a horizontally spread wide beam, as required. 10 A driving light is any light used on a vehicle to assist in night vision or improving visibility. Thus driving lights include head lights, spot lights, flood lights, fog lights, or other lights used by a driven vehicle. Applications include use for passenger vehicles and craft, recreational vehicles and craft, agricultural machinery and mining equipment. 15 The light source may be any suitable source, such as a luminescent filament or LED. The light source is held in a fixed position relative to the internal reflective surface. The light source will be powered by battery or other suitable means. The housing is the outermost portion of the light. The housing 20 provides rigid support to the light and allows the light to be mounted on a vehicle. Additionally the housing forms the outermost limit of the light, thereby restricting the travel of light around the light source. The housing may contain the light source by providing a physical limit encouraging the light to reflect off the housed internal reflective surface and thereby 25 focus into a beam of light. In particular the location of the light source and the shape of the housing affect the size of beam produced, with a parabolic shaped reflective surface containing the light source at the focal point creating an optimal reflected light beam. An internal reflective surface compels the light rays to reflect according 30 to the property angle of incidence equaling the angle of reflection. Thus the shape of the reflective surface determines the concentration of light. Thus a beam may be achieved by providing a suitably curved reflective surface, typically an elliptical or parabolic curve, behind the light source. The reflective surface may be formed of any WO 2005/025934 PCT/AU2004/001235 3 suitable material, such as a coating of silver coloured paint, thin layer of foil, thin layer of metal, a surface made of reflective plastic or other suitable means. The reflective surface will preferably be generally elliptical in shape. Alternatively, the internal reflective surface may be parabolic. 5 The internally reflective surface is positioned relative to the light source, so that the light source will generally be fixed at the focal point of the reflective surface. The reflective surface includes at least one horizontally disposed portion. In one embodiment, the horizontally disposed portion may be a section of the 10 reflective surface which can be displaced horizontally relative to the reflective surface. Alternatively the horizontally disposed portion may be integral with the reflective surface and capable of being displaced by a suitable means. In the first embodiment, the horizontally disposed portion is preferably elliptical and is a generally horizontal section across the width of the internal 15 reflective surface. The height of the section will determine the amount of light beam spread, with a wider section dispersing the concentrated spot beam and increasing the intensity of the wider beam portion. The elliptical shape is preferable and allows the curvature of the internal reflective surface to be followed. The wider the section of the horizontally disposed portion, the wider the spread of the light beam when the 20 light rays are dispersed. In a second embodiment the means for displacing the horizontally disposed portion is a clamp which distorts the reflective surface horizontally. In a preferred second embodiment the clamp is formed from muscle wire attached to two or more points on the reflective surface, said muscle wire being contractible to distort 25 a contractible internal reflective surface. Other means of clamping or squeezing such as using springs or jaws may be used to distort the internal reflective surface, as would be understood by a person skilled in the art. Springs may be used to locate and support the internal reflective surface relative to and within the housing. Thus the focused light beam may be adjusted horizontally by displacing 30 the horizontally disposed portion. When said portion is not displaced, the internal reflective surface is generally elliptical reflecting the light rays to form a concentrated light beam. In an optimum configuration, when the horizontally disposed portion is maximally displaced, the beam will be dispersed horizontally to form a light beam WO 2005/025934 PCT/AU2004/001235 4 with a wider horizontal spread and including a central concentrated portion. By displacing the horizontally disposed portion, light reflected from the upper and lower portions of the reflective surface focus as a concentrated light beam, regardless of the displaced portion. When the horizontally disposed portion is not 5 displaced, the horizontal light rays are focused to the same concentrated light beam forming a spot. The beam elongates horizontally as the horizontally disposed portion displaces relative to the light source. When the horizontally disposed portion is fully displaced, only the horizontal rays are deflected changing the shape of the light beam to form the horizontally wide spread beam. 10 A user may produce a range of beams in between these extremes by adjusting the displacement of the horizontally disposed portion to form the desired beam arrangement. The displacement is adjusted by using a drive to affect the displacement of the horizontally disposed portion towards and distal to the light source, in a horizontal plane. 15 The drive may be a cam and arrangement of gears, or other mechanical means, driven manually or by an electrical motor. Preferably, a slot cam is connected to the horizontally disposed portion and a gear, the gear being driven to rotate engaging the cam said rotational motion translating to displace the horizontally disposed portion in a horizontal plane relative to the light source. The drive may be 20 driven by an electric motor. Preferably the drive may be controlled by an electronic switching device. An electronic switching device may be fixed for instance to a dash board or remote, as required. Preferably an opto-coupler may be used to synchronise lighting. BRIEF DESCRIPTION OF DRAWINGS 25 The Invention will now be described in reference to the drawing in which: Figure 1 shows a back perspective view of the invention; Figure 2 shows a front perspective view of the invention; Figure 3 shows a front perspective view of the invention; 30 Figure 4 shows a front view of the invention; Figure 5 shows a view of the spread of the light beam; Figure 6 shows a top and sectional view of the invention; Figure 7 shows a range of light beam spread paths from the invention WO 2005/025934 PCT/AU2004/001235 5 from a top view; Figure 8 shows a front view of a second embodiment of the invention; Figure 9 shows a front view of a second embodiment of the invention; Figure 10 shows a perspective view of a second embodiment of the 5 invention; Figure 11 shows a front view of a second embodiment of the invention; and Figure 12 shows a front view of a second embodiment of the invention in a compressed configuration. 10 DESCRIPTION As shown in Figures 1, 2 and 3, the driving light 10 a driving light having a light source 50, an internal reflective surface 30 positioned relative to the light source 50 and a housing 20 to contain the light source 50 and the internal reflective surface 30. The internal reflective surface 30 comprises at least one 15 horizontally disposed portion 40. In a first embodiment,' the focus is achieved by displacing the horizontally disposed portion 40 using a drive 60. The drive 60 comprises a slot cam 61 driving the horizontally disposed portion 40 by means of a gear 62 in turn driven by an electric motor 63. 20 The horizontally disposed portion 40 may be driven between an integral position where the portion forms a part of an internal reflective surface 30, or a displaced position, where the horizontally disposed portion is maximally extended, distal from the light source 50 in a horizontal plane. As illustrated in Figure 4, the horizontally disposed portion 40 extends 25 across the width of the light 10 and surrounds the light source 50. By providing the horizontally disposed portion 40 in a curved shape, it matches the curvature of the internal reflective surface 30. Figures 5 and 7 show the spread of the light beam, with Figure 7 showing a variety of beams spreading form the light 10, as viewed from above. These 30 beams illustrate a range of beams achievable by the invention, without showing the intermediate paths also achievable. Figure 5 illustrates the spread being horizontal and the concentrated spot formed by the undistorted portion of the internal reflective surface 30.

WO 2005/025934 PCT/AU2004/001235 6 Figure 6 shows a top and sectional view of the drive 60 including the electric motor 63, which drives the gear 62 to engage the slot cam 61 which translates the rotational movement of the gear into horizontal displacement of the horizontally disposed portion 40 relative to the light source 50. The remainder portion of the 5 internal reflective surface 30 is not displaced, as can be seen in the drawing. A second embodiment of the invention is shown in Figures 8 to 12. In this embodiment, the internal reflective surface 30 is distortable as the horizontally displaced portion 40 is squeezed by muscle wire 70 contacting two points on the internal reflective surface 30, thereby contracting said internal reflective surface 30 10 vertically. In particular, Figures 9 and 11 illustrate the embodiment in a control position, while Figures 8 and 12 show the embodiment in a collapsed position. Vertical springs 71 are used to support the internal reflective surface 30 relative to the housing 20. Additional horizontal springs 72 may be used to align the internal 15 reflective surface 30, as shown particularly in Figure 9. Whilst the above has been given by way of illustrative example of the invention, many modifications and variations may be made thereto by persons skilled in the art without departing from the broad scope and ambit of the invention as herein set forth. 20 The term "comprise," or variations of the term such as "comprises" or "comprising," are used herein to denote the inclusion of a stated integer or stated integers but not to exclude any other integer or any other integers, unless in the context or usage an exclusive interpretation of the term is required.

Claims (6)

1. A driving light including: a light source; 5 an internal reflective surface positioned relative to the light source; and a housing to contain the light source and the internal reflective surface; wherein the internal reflective surface comprises at least one elliptical horizontally disposed portion that extends across the width of the internal reflective surface and is arranged to be translated in a horizontal plane relative to the reflective 10 surface.

2. A driving light according to claim 1 wherein the light source is located at or near the focal point of the internal reflective surface whereby the light rays traveling behind the focal point reflect from the internal reflective surface, including the horizontally 15 disposed portion, to form a beam of light of wider or narrower spread and wherein by displacing the horizontally disposed portion, the focus of the light is adjusted so that the light beam forms a range of beams from a spot beam to a horizontally spread wide beam, as required. 20

3. A driving light according to claim I or claim 2, wherein the internal reflective surface is generally parabolic.

4. A driving light according to any one of the preceding claims wherein the horizontally disposed portion is a section of the reflective surface which can be displaced 25 horizontally relative to the reflective surface.

5. A driving light according to claim I wherein the driving light further includes a drive wherein said drive includes a cam and an arrangement of gears wherein the cam is connected to the horizontally disposed portion and a gear, the gear being driven to rotate engaging the cam whereby said rotational motion translates to displace the horizontally 30 disposed portion in a horizontal plane relative to the light source. 8

6, A driving light substantially as described herein with reference to Figures 1 to 5. * * *