EP0860652A2

EP0860652A2 - Vehicle signal lamp

Info

Publication number: EP0860652A2
Application number: EP98300941A
Authority: EP
Inventors: Francis Thompson; Nicholas William Tysoe
Original assignee: Britax Vega Ltd; Koito Europe Ltd
Current assignee: Koito Europe Ltd
Priority date: 1997-02-22
Filing date: 1998-02-10
Publication date: 1998-08-26
Also published as: JPH10241415A; GB9703712D0; EP0860652A3

Abstract

A vehicle signal lamp has a reflector (32) arranged to direct light from a bulb (30) through a hole (36) in an opaque mask (34). The mask (34) has a concave reflective surface (40) covered by a transparent coloured layer (42) and arranged to reflect light incident thereon from outside the lamp. The colour of the lamp when not illuminated is determined by the colour of the coloured layer (42). Light from the bulb (30) does not pass through the layer (42) and therefore is not affected by its colour.

Description

This invention relates to a vehicle signal lamp of the type having a reflector and a substantially parallel-sided transparent outer cover, optical distribution of the light output from the lamp being controlled by the reflector.

In known lamps of this type, the reflector takes the form of a slightly distorted parabola so as to produce a divergent beam of light. Alternatively, the reflector may be a true parabola with a mesh of pillow optics on its surface. The reflector surface is easily visible through the outer cover which is made of a material of the colour required for the light to be emitted by the signal lamp.

It has become customary for vehicle signal lamps to be constructed so that when they are not illuminated, they take up the colour of their surroundings. For example, a reversing lamp is required to emit white light when it is illuminated but is commonly arranged to appear red when not illuminated so as to conform to the appearance of adjacent rear lamps. Such lamps are commonly described as chromatic lamps. Chromatic lamps have required the provision of optical elements on the outer transparent cover or lens. An object of the present invention is to provide a chromatic lamp in which the outer transparent cover is substantially parallel-sided and does not have any effect on the distribution of the emitted light.

According to the invention, a vehicle signal lamp of the type described above has an opaque mask disposed between its reflector and its outer cover with a central opening through which light from the reflector reaches the outer cover, the mask comprising a concave reflector covered by a transparent coloured layer and arranged to reflect light incident thereon from outside the outer cover.

The colour of the transparent coating is chosen in accordance with the required appearance of the lamp when not illuminated.

An embodiment will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a horizontal sectional view of a known vehicle signal lamp of the type described in the first paragraph above;

Figure 2 is a cross-sectional view, similar to Figure 1, of a vehicle signal lamp in accordance with the invention; and

Figure 3 is a scrap sectional view of a modified mask for use with the lamp shown in Figure 2.

Referring to Figure 1, a vehicle signal lamp of the known type comprises a bulb 10, a parabolic reflector 12 and a transparent outer cover 14. The outer cover 14 is parallel-sided and does not affect the distribution of the emitted light. The reflector 12 has pillow optics, such as the formations 16, on its front surface which has a metallised reflective coating 18.

The transparent cover 14 is coloured in accordance with the required colour of the emitted light, for example, red. Emitted light such as the

rays

20 and 22 are coloured by the cover disk 14. Similarly, incident white light from outside, such as the ray 24, is reflected as the ray 26 which has been coloured both on its inward and outward passage through the cover 14.

Referring to Figure 2, a signal lamp in accordance with the invention comprises a bulb 30 surrounded by a reflector 32 of shape between a paraboloid and an ellipsoid arranged to give a dispersed convergent beam. In front of the reflector 32 is an opaque mask 34 having a central hole 36. In front of the mask 34 is a parallel-sided transparent cover 38 which does not have any effect on the dispersal of the emitted light.

The mask 34 has pillow optics 40 on its front surface which has a metallised reflective layer on top of which is a transparent coating 42 coloured in accordance with the required appearance of the signal lamp when the bulb 30 is not illuminated. The effect of this is that light from the bulb 30 is reflected by the reflector 32 and emerges as rays such as the

rays

44, 46, 48 and 40 which are do not pass through the coating 42 and therefore are not affected by its colour. As described, the light emitted is white light, suitable for use as a reversing lamp. If coloured light is required, then either the bulb 30 is replaced by a coloured bulb or a coloured filter (not shown) is fitted to fill the hole 36.

Incident white light from the outside of the cover 38, such as that illustrated by the ray 42, is reflected as ray 44 and is coloured by the coating 42 on the metallised surface 40 of the mask 34.

Since vehicle lamps are required to give a beam which is more widely divergent in the horizontal direction than in the vertical direction, the reflector 32 is not symmetrical about the optical axis of the lamp. Instead it has an opaque flat bottom wall 46 which is of the same colour as the transparent coating 42. The effect of this is that any downwardly incident light which passes through the hole 36 falls on the coloured wall 46 with the result that, if it re-emerges through the hole 36 after having been reflected subsequently by the reflector 32, it is also coloured in accordance with the required non-illuminated appearance of the lamp.

Figure 3 illustrates a modified mask 60 which can be used in place of the mask 34 of Figure 2. The modified mask 60 is moulded from transparent material coloured in accordance with the required non-illuminated appearance of the lamp and has pillow optics and a bright metallised coating 62 on its rear surface.

Claims

A vehicle signal lamp having a reflector (32) and a substantially parallel-sided transparent outer cover (38), optical distribution of the light output from the lamp being controlled by the reflector (32), characterised in that an opaque mask (34, 60) is disposed between the reflector (32) and the outer cover (38) with a central opening (36) through which light from the reflector (32) reaches the outer cover (38), the mask comprising a concave reflective surface (40, 62) covered by a transparent coloured layer (42, 60) and arranged to reflect light incident thereon from outside the outer cover (38).
A vehicle signal lamp according to claim 1, wherein the mask (34) has its reflective layer on its surface nearer to the outer cover (38) and a transparent coloured coating (42) on its reflective layer.
A vehicle signal lamp according to claim 1, wherein the mask (60) is formed from transparent coloured material and has its reflective layer (62) on its surface further from the outer cover (38).