U.S. Philips Corporation

Koninklijke Philips Corporation N.v.

Paul Hellwig

Werner Schlagheck

Juergen Schoeneich

Michael Haacke

Dieter Wilhelm

Marcus Kubon

Ralf Muckel

Pieter Postma

Bernd Mackovika

Wolfgang Hahn

A high-pressure gas discharge lamp (HID &lsqb;high intensity discharge&rsqb; lamp) is described which is designed in particular so as to be free from mercury and suitable for use in automobile technology. To achieve improved lamp properties, in particular a substantially equal luminous efficacy compared with lamps of the same power and having a gas filling with mercury, as well as a burning voltage which is as high as possible, a geometry is proposed for the discharge space ( ) which raises the temperature of the coldest spot in the lamp to such a degree that the light-generating substances can enter the gas phase to a sufficient extent also without mercury, and in particular in combination with the use of a metal halide as a voltage gradient generator.

High-pressure gas discharge lamp

A discharge lamp is disclosed comprising an enclosed discharge vessel for the generation of an electrical discharge and a casing made of glass which surrounds the discharge vessel. In order to achieve as constant properties as possible over the service life of the lamp, it is proposed that the glass material of the casing be doped with sodium in a concentration of at least 10 ppm, and preferably at least 30 ppm. According to a further embodiment, it is proposed that other alkali metals (except for sodium) be contained in a maximum concentration of 25 ppm. Surprisingly, by the appropriate choice of the outer bulb, not in direct contact with the actual discharge, the diffusion of sodium from the discharge vessel is reduced. In addition to this, the material of the outer bulb has a reduced inclination to crystallization.

Discharge lamp and outer bulb therefor

The lamp/reflector unit comprises a reflector (1) having a neck-shaped portion (3) in which a metal centering member (9) is present. The centering member (9) has a transverse wall (10) with an opening (11) in which the seal (6) of an electric lamp (4) is accommodated, secured with cement (12). Recesses (13) extend from the opening (11) into the transverse wall (10). Fracture of the seal (6) is thus prevented.

Lamp/reflector unit

In an electrical lamp, whose envelope is closed by a pinch of rectangular cross-section, through which current-supply conductors are passed and which is supported in a cap between inwardly projecting parts, which seize around the narrower side faces of the pinch, according to the invention, one of the current supply conductors is bent backwards with its part projecting from the pinch along one of the narrower side faces and is clamped between pinch and lamp cap. Thus, it is possible to use a cap having only one bottom contact and nevertheless to secure the lamp envelope to the cap without additional means.

Electric lamp having a pinch supported in a sleeve-shared cap

In an electric lamp, the lamp bulb has a flat pinch, on the minor faces of which there are recesses into which projections on the cap are locked. The lamp bulb is thus secured against rotation and translation in the cap, and the power leads are not under mechanical stress.

Electric lamp with a sleeve-shaped cap

In an electric lamp with a sleeve-shaped cap and an inner sleeve carrying the bulb, the cap has at least two lugs protruding inwards and the inner sleeve is provided with at least two slots on its cylindrical sheath, which engage the lugs.

In an electric lamp with a sleeve-shaped cap 12, in which an inner part 8, fitted to accommodate the lamp bulb 1, consists of a cover plate 9 with at least two spring clips 10 attached to the inside wall of the cap 2 and provided with openings 11, the sleeve-shaped cap 12 is provided with at least two projections 13 protruding inwards, over which, when the inner part 8 is inserted into the cap 12, the spring clips 10 fit and lock into position, by means of the openings 11 which correspond to the cross-section of the projections.

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Aachen, Germany

Paul Hellwig