Illumination – Light modifier – Translucent or opaque
Patent
1985-12-16
1986-12-16
Nelli, Raymond A.
Illumination
Light modifier
Translucent or opaque
362346, 362293, F21V 1100, F21V 916
Patent
active
046301844
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The present invention relates to motor vehicle lamps of the type comprising: rays emitted by the bulb and focusing them outwardly into a beam having predetermined characteristics, and
Motor vehicle lamps of the type specified above have been known and used for some time (see, for example, German patent application No. 12 59 747) and allow the transparent glass of the lamp to be formed in colours different from that expected of the light from the lamp. More particularly, the transparent glass may be colourless even when the light from the lamp must be yellow or red, for example.
In lamps of this type, however, there is the problem of preventing the coloured filter within the lamp body from being visible from the exterior when the bulb is off and the lamp is illuminated from the exterior, for example by sunlight.
The object of the present invention is to provide a lamp of the type specified above, which on the one hand allows this problem to be solved and on the other hand has a relatively simple and cheap structure.
The main characteristic of the lamp according to the invention lies in the fact that the prismatic internal surface of the transparent glass includes diffusing lenses for scattering light rays passing through the transparent glass from the exterior in all directions within the body of the lamp, and in that the lamp further includes an internal reflective wall for reflecting the light rays scattered within the body of the lamp over the entire internal surface of the transparent glass, so as to prevent the coloured filter from being visible from the exterior when the bulb is off and the lamp is illuminated from the exterior. In this condition, the transparent glass takes on a colour corresponding to that of the internal reflective wall. It is thus possible, in sunlight, to make the glass take on the appearance of a desired colour (for example, the colour of the adjacent part of the motor vehicle bodywork) or to keep its colourless appearence.
In a first embodiment, the internal reflective wall is located between the bulb and the transparent glass and has a central aperture of such a size as to allow the passage of only those light rays coming directly from the bulb which are incident on the surface of the transparent glass.
In a second embodiment, the internal reflective wall is instead in the form of a conical surface surrounding the light bulb.
In the case of the first embodiment, a liquid crystal element is preferably located between the internal reflective wall and the transparent glass, which can be switched between two operating states in which the liquid crystals are substantially transparent and substantially opaque, respectively.
By virture of this characteristic it is possible, when the bulb is on and the lamp is illuminated from the exterior (for example by the headlights of a following motor vehicle), to prevent the internal reflective wall from reflecting the light rays entering the lamp from the exterior and altering the characteristics of the beam emitted by the lamp.
The same problem is avoided in the second embodiment by the provision of a reflector between the internal reflective wall and the transparent glass, which has a prismatic surface for reflecting light rays from the bulb to the exterior and for refracting light rays from the exterior of the lamp, with the exception of light rays coming from the exterior in a direction substantially parallel to the optical axis of the lamp, onto the internal reflective wall.
The invention also provides a light unit for motor vehicles, characterised in that it includes several lamps of the type specified above, having the body and the transparent glass in common.
Further characteristics and advantages of the present invention will become apparent from the description which follows with reference to the appended drawings, provided purely by way of non-limiting example, in which:
FIG. 1 is a sectional view in a horizontal plane of a first embodiment of the lamp according to the present invention,
FIG. 2 illustrates a variant of
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Fiat Auto S.p.A.
Nelli Raymond A.
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