GB2221526A

GB2221526A - Motor-vehicle light

Info

Publication number: GB2221526A
Application number: GB8917242A
Authority: GB
Inventors: Heinrich Schaefer
Original assignee: Hella KGaA Huek and Co
Current assignee: Hella GmbH and Co KGaA
Priority date: 1988-08-03
Filing date: 1989-07-28
Publication date: 1990-02-07
Also published as: FR2635166B1; GB8917242D0; DE3826330A1; FR2635166A1; AU3883589A

Description

1 MOTOR-VEHICLE LIGHT 2 2 2' 1 115 12- 6 The invention relates to a

motor-vehicle light, particularly but not necessarily exclusively a reversing light.

In indicator lights for motor vehicles, it has become current practice to dispose deflection glasses or intermediate glasses in a suitable position between the lamp glass and the incandescent lamp. This intermediate glass consists of a number of transparent parts which are each disposed in the optical axis of collecting optical elements. Grid- form diaphragm gratings between the light source and the lamp glass ensure that the shielding of the light is restricted to an extent which is necessary to allow through all the rays focused by the collecting lenses but also allows a colour reflection, which ensures a desired coloured impression of the light, to issue from the diaphragm grating even when its lamp is not switched on.

In GM 8533666, a light is described wherein the proportion of the area of regions impermeable to illumination was further increased in comparison with that of the permeable regions, primarily in order to achieve an improvement in the appearance or colour impression in the unswitched-on state. The fact that less refraction of the light beams occurs in the light-permeable region as a result of the concave refraction regions at the outer face of the scattering element may appear adequate for use in an 2 indicator light but not for a reversing light. Very different demands are made on this with regard to illumination distribution and intensity in connection with the directional characteristic of the light.

It is therefore the object of the invention to develop a motor-vehicle light so that despite the use of a diaphragm grating and a lamp glass constructed in the form of a filter, the optically effective elements ensure the light distribution required by EEC rules and Section 52 of the German motor vehicle construction and use regulatúons, with the desired intensity of illumination.

According to the invention, there is provided a motor-vehicle light, particularly a reversing light, having an incandescent lamp, optical means for forming a generally is parallel beam from the illumination from said lamp, a lamp glass constructed in the form of a filter and a further glass disposed between the lamp and said lamp glass, said further glass being provided, on its outer face, with a screen comprising light passages with optically effective surfaces that have, in alternating sequence, opposite inclinations at an angle of less than 900 to planes extending parallel to the optical axis of said beam, and said further glass being provided on its inner face with convex optical means situated opposite the light passages, regions of the screen impermeable to light being situated opposite grooves in said inner face which are substantially V-form in cross-sect on.

Preferably, the inclinations of said optically 1 1 3 effective surfaces are at an angle of about 800. Such a light is particularly suitable as a reversing light in which the outer cover glass is constructed in the form of a filter and as a rule absorbs a large proportion of the light. Therefore it is an advantage that the light is radiated directed very deliberately in certain angular regions which simultaneously represent the measuring points for the necessary light intensity values.

Further advantages can be obtained by forming said grooves so that the parallel beam impinging on the middle of a side of each groove is deflected onto the middle of plane-faced light passages, and in making the grooves so deep that light impinging on a groove side emerges as a whole from the light passages. At the same time, the area of the light exit can be made so large that the whole of the light impinging on the sides of the grooves passes through the light passages. This light, thus collected, transmitted and directed, of all the basic bundles of rays forming the radiated light, corresponds precisely to the standard specifications for a reversing light. In this case, the prismatic grooves enable the light directed into the light passages to be guided further in a concentrated manner without substantial scattering.

In a further development the convex optical means can form an obtuse angle at the end face to contribute very substantially to this desired result. Thus four plane surfaces at the entry side, which together represent a collecting optical means, can afford all the prerequisites 4 for a closed and concentrated guiding of the light through the passages in the diaphragm grating. At the same time, a glass, provided with these optical means offers advantages for the design of a tool for its production, in that it is only a question of forming plane surfaces which do not have any undercutting and are able thus to be generated in a straightforward manner involving little expense.

By way of example, the invention will be described in more detail with reference to the accompanying drawing which shows a motor-vehicle light in the form of a reversing light. In the drawing:

Fig. 1 shows the construction of the reverwing light in cross-section, and Fig. 2 shows the cross-section of the is intermediate glass provided with optical means, incorporated in the light.

In the example shown, an intermediate glass 4 is disposed between a lamp glass 1 constructed in the form of a filter and a reflector 3 behind which is a light source 2, specifically an incandescent lamp. The illumination falling on a reflector 3 or a prism glass (not shown) is aligned in a parallel beam and falls, as illustrated in Fig. 2, on convex optical means 5, which are obtuseangled in shape at the inner or entry side, and on V-form grooves 6 of the intermediate glass 4 bounding them laterally. Disposed centrally opposite the grooves 6, at the outer or exit side of the intermediate glass 4, are regions 7 which are impermeable to light.

j Situated opposite the optical means 5, at the exit side, are light passages 8, the plane exit surfaces 9 of which are given, in alternating sequence, opposite inclinations at a positive and negative angle (a) to the vertical planes extending parallel to the optical axis 10. Thus assurance is provided that all the rays of light impinging in parallel on the intermediate glass 4 are guided in the optimum manner by the convex optical means 5 and the sides of the V-form grooves 6 bounding them laterally, onto the exit surfaces 9 of the light passages 8, so that the minimum illumination intensities necessary for a reversing light at its measuring points are attained without any problems.

This is also achieved under conditions where it is a question of a grey reversing light in which the lamp glass 2 is coloured grey, the intermediate glass 4 is clear and the regions 7 which are impermeable to light represent black or silvery strips. In the case of a coloured lamp, for example of red appearance, the lamp glass 2 is pink, the intermediate glass 4 is coloured light blue and the regions 7 which are impermeable to light represent red strips. Depending on requirements, it is possible to provide the lamp glass 2 additionally with dispersive means.

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Claims

A motor-vehicle light, having an incandescent lamp, optical means for forming a generally parallel beam from the illumination from said lamp, a lamp glass constructed in the form of a filter and a further glass disposed between the lamp and said lamp glass, said further glass being provided, on its outer face, with a screen comprising light passages with optically effective si=faces that have, in alternating sequence, opposite inclinat:Lons at an angle of less than 900 to planes extending parallel to the optical axis of said beam, and said further gl-a7ss being provided on its inner face with convex optical means situated opposite the light passages, regions of the screen impermeable to light being situated opposite grooves in said inner face which are substantially V-form in crosssection.
2. A motor-vehicle light according to claim 1, wherein said inclinations are about 800 to said planes parallel to the optical axis.
3. A motor-vehicle light according to claim 1 or claim 2, wherein the illumination impinging on the middle of a side of a V-form groove is deflected onto the middle of a light passage on the outer side of the further glass.

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4. A motor-vehicle light according to any one of claims 1 to 3, wherein the depth of the grooves is sufficient to permit illumination impinging on a side of a groove to emerge as a whole from a light passage.
5. A motor-vehicle light according to any one of claims 1 to 3, wherein the.light passages have optically effective surfaces sufficiently wide to permit the whole of the illumination impinging on the sides of the grooves to pass through.
6. A motor-vehicle light according to any one of the preceding claims, wherein the convex optical means form an obtuse angle at the end face.
7. A motor-vehicle light constructed and arranged for use substantially as described herein with reference to the accompanying drawing.
8. A reversing light according to any one of the preceding claims.

Published 1990 at The Patent Office. State House. 66 71 High 1.1olborn, London WC1314TP.Flurther copies maybe obtalnedfrom The Patent OfrIce. Sales Branch. St Mary Cray. Orpington. Kent BR5 3pr Printed by Multiplex techniques ltd. St Mary Cray. Kent, Con. 1187