Light projector equipped with a low-voltage incandescent lamp and incorporating a relay
AssigneeU.S. Philips Corporation
InventorsJean-Pierre R. Coulmance, Jean-Pierre Ricouard
Life of this patent
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Abstract
A motor-car headlight with a built-in static relay. The headlight lamp is connected in series with a power phototransistor with which it is optically coupled. Turn on and turn off of the phototransistor is effected by temporarily changing the base voltage.
Claims11
A light projector comprising a low-voltage incandescent lamp, a shell which is internally coated with a reflecting metallic layer and which includes a socket for the lamp comprising at least two electric contacts, a phototransistor, means including said two electric contacts for connecting the lamp and phototransistor in series to a source of voltage, the phototransistor being arranged so as to intercept a fraction of the luminous flux emitted by said lamp, and means for switching the base of the phototransistor to the source of voltage.
An electro-optic device comprising, a housing, an electrically energizable light source mounted in said housing, a photosensitive element connected in series circuit with said light source to a source of supply voltage and mounted so as to be shielded from any external light source and optically coupled solely to said electrically energizable light source so as to receive a fraction of the luminous flux emitted by said light source, and switch means coupled to a control electrode of said photosensitive element for selectively coupling the control electrode to the source of supply voltage to initiate current flow in said series circuit whereby the light source maintains current conduction in the photosensitive element and light source by means of said optically coupled fraction of emitted luminous flux after the switch means decouples the control electrode from said voltage source.
Dependencies are inferred from the claim text.