U.S. Philips Corporation

Bertus De Vrijer

Leonard C Eijkelenboom

Jan De Ridder

The high-pressure discharge lamp has a discharge vessel (1) with neck portions (7) of reduced width. The electrode pins (9) have at their free ends an electrode head (10), whose largest diameter is larger than the diameter of the electrode pins (9). Due to the fact that the electrode head (10) must be able to pass through a duct in the neck portion (7) of reduced width when the lamp is assembled, the electrode (2) has lateral play, which may lead to a non-centered position of the electrode (2) in the discharge vessel (1). In the lamp according to the invention, this disadvantage is mitigated in that the electrode pin (9) in the neck portion (7) of reduced width has a transverse dimension which is larger than the diameter of the pin (9), for example due to the presence of a flattened part (11).

High-pressure discharge lamp

The headlight system has a pair of low beam and a pair of high beam lamps (1a, 1b; 2a, 2b) adapted to be mounted in the front part (3) of an automobile with one lamp of each pair to a respective side of the front part. The lamps each have a flattened concave reflector, a high-pressure discharge arc in a translucent envelope as a compact light source, and a substantially quadrangular lens. The ratio of width and height of the lens is larger than 3 and the height is smaller than 6 cm. The low-beam lamps produce a beam of uniform brightness, large width and length and sharp light darkness transitions, as a result of which the risk of dazzling is small despite a large viewing distance.

Headlamp system

A gas discharge lamp according to the invention has an at least approximately rectilinear and contracted arc and a high efficiency even in a horizontal operating position. Consequently, the lamp is suitable for use, when arranged in a reflector, as a vehicle headlight lamp. The lamp comprises an ionizable filling of rare gas, mercury, and metal iodide, the quantity of mercury being dependent upon the inner diameter D of the lamp envelope (1), the distance d between the tips of the electrodes (2), and the distance l over which the electrodes project into the lamp envelope. The values of D, d, l and the wall thickness t of the lamp envelope lie within indicated limits. The lamp, which may be provided with a screen, may have a lamp cap or may be incorporated into a reflector with a front pane.

Metal halide discharge lamp

In the electric incandescent lamps having an infrared radiation-reflecting filter which is pervious to visible light, the efficiency can be increased by adapting the geometry of the filter and the geometry of the filament to each other. According to the invention, the filter comprises a major portion of a prolate ellipsoid of revolution and a cylindrical filament extends between the foci thereof, the distance between focal points being from 1-2 times the length of the filament.

Electric incandescent lamp

A high-pressure mercury vapor discharge lamp comprising tin iodide, tin chloride and tin bromide in addition to a rare gas and mercury. The molar fraction of iodine is at least 0.20, the molar fraction of bromine at least 0.25 and the molar fraction of chlorine at least 0.05.

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Eindhoven, Netherlands

Bertus De Vrijer