U.S. Philips Corporation

Johannes H Beurskens

Bauke J Roelevink

Christiaan Prozee

Wilhelmus H Winkelmolen

The lamp envelope of the electric lamp is coated at the inner surface with an electrostatically applied light-scattering pigmented powder layer. The powder layer comprises at least a cadmium-containing pigment and further a cadmium-free pigment for example in approximately equal part by weight. Although cadmium-free pigments alone cannot give lamps the desired color properties, it has been found that they are capable of replacing cadmium-containing pigments in the powder layer up to a high percentage by weight.

Electric lamp having a strongly colored lamp envelope

A lamp includes a tube which forms part of a sealed vessel, extending between a lamp cap and a pinch at an end of the tube inside the vessel. A current supply conductor extending between a cap contact and a light source inside the vessel includes a fuse wire portion which is embedded in an electrically insulated mass within the tube, part of the fuse wire portion being free of the insulating mass, between the mass and the lamp cap.

Internally fused electric lamp with partially embedded fuse wire

The electric lamp in accordance with the invention has a bayonet lamp cap (3) which is coupled to the neck-shaped portion (2) of the lamp envelope (1) by means of projections (7) and guides (8) co-operating therewith. The coupling is locked against displacement by means of a solidified mass (10). The co-operation between the cams (7) and the guides (8) is obtained by a rotation of the lamp cap (3) with respect to the lamp envelope (1) in counterclockwise direction until the cap abuts the envelope, the abutting stopping further rotation.

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Weert, Netherlands

Johannes H Beurskens