U.S. Philips Corporation

Friedrich Hermann Almer

Heiner Kostlin

Germain R T'Jampens

Jan De Ridder

An incandescent lamp has a hollow cylindrical filament which is constructed from transversal strips each traversing at least for the greater part the circumference of the cylinder at a distance from each other with longitudinal strips connecting the transversal strips together. The strips constitute electrically parallel current paths. Such filaments have improved resistance to deformation a low sensitivity for evolving hot spots, a low weight and compactness.

Electric incandescent lamp with cylindrical filament

The thermal radiation which is emitted by an electric incandescent lamp is eliminated according to the invention by providing an incandescent lamp with a filter which transmits visible light and which reflects infrared radiation, which filter consists of an interference filter and a heavily doped metal oxide filter which is disposed at the side of the interference filter which is remote from the filament body.

Incandescent lamp with infrared filter

In a two-pinch halogen lamp having an axial filament and an envelope diameter of less than 3.5 mm the envelope diameter is chosen as a function of the envelope and filament temperature, the coil diameter and the filling pressure.

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Eindhoven, Netherlands

Friedrich Hermann Almer