Metal halide gas discharge lamp for projection purposes
AssigneePatent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbH
InventorsClemens Barthelmes, Thomas Dittrich, Ralf Seedorf
Life of this patent
Estimating the term…
Abstract
A metal halide gas discharge lamp for projection purposes includes a discge vessel closed at both ends preferably has between the electrodes a central frosted partial area applied on the outer surface of the discharge vessel. The relationship 0.1<B.ltoreq.1, preferably 0.4<B/d<0.8, applies to the quotients of the width B of the frosted partial area by the inter-electrode gap d. The lamp is optionally provided on one or both sides with heat build-up coatings. The lamp advantageously forms a unit with an optical reflector.
Claims9
A metal halide gas discharge lamp (1) for projection purposes, having a translucent discharge vessel (2) closed on two ends (3);
- an ionizable fill within the vessel;
- two opposed electrodes (4) in the vessel, separated by an interelectrode gap, connected to power supply leads (8) carried to the outside;
- and
- a frosting forming a strip-like portion (14) on the circumference of the outer surface of the discharge vessel (2),
- characterized in that
- the frosted portion (14) is located in alignment with the interelectrode gap, and has a width which is less than or at most equal to the electrode spacing defining said interelectrode gap;
- and
- regions of clear surface of said vessel (2) adjoin each of the edges of the strip-like portion of the frosted outer surface.
Dependencies are inferred from the claim text.