Patent Treuhand Gesellschaft Fur Elektrische Gluhlampen Mbh

Lutz Klein

Ernst Panofski

Alexander Dobrusskin

Dieter Hofmann

Josef Plischke

Roland Kastl

Wolfgang Albrecht

Hans Joachim Schmidt

Gerd-Otto Eckstein

Gunter Woizan

At least two discharge units (2, 3; 14, 15, 16; 21, 22, 23, 27, 28, 29) are ocated adjacent each other, each of the discharge units preferably including a unitary U-shaped tube having two longitudinal leg portions (2a, 2b; 3a, 3b) extending parallel to each other, and a cross portion (4, 5) connecting the leg portions at the base of the U. The free ends of the U are pinch-sealed and air-tight, and the two discharge units are so positioned relative to each other that the longitudinal leg portions extend parallel to each other, selectively, in a single plane, in parallel planes, or angled with respect to each other; the cross elements are located at adjacent end portions of the respective units. One filament-carrying electrode is sealed into one free end of one leg of one U-shaped tube of one unit, and another filament-carrying electrode is sealed into a free end of one leg of another unit; the units are cross-connected to provide a continuous discharge path, the cross connection being effected adjacent pinch-sealed ends of those legs of the U-shaped tubes which do not have filament-carrying electrodes sealed therein. To facilitate lamp starting, an auxiliary electrode (116) is pinch-sealed adjacent the cross connection, and coupled by an impedance (117) to the 'hot' filament-carrying electrode.

Multiple-tube compact low-pressure discharge fluorescent lamp

To prevent weakened corners when forming a U-shaped discharge tube with sharp corners (28, 29) during a bending operation from a straight tube, two glass tubes (1, 3) having a wall dimension suitable for a compact fluorescent tube are fused to a central tubular glass element (2) of thicker wall dimension so that, upon bending into U-shape with sharp corners (28, 29), the thicker wall portion can stretch and form the essentially right-angle corners of requisite wall thickness. Preferably, during the heating steps for forming the glass, the initially straight glass portions (1, 2, 3) are rotated.

Method of making a unitary tubular generally U-shaped discharge vessel,

A tubular discharge vessel for a compact low pressure discharge lamp, espally a compact fluorescent lamp, is formed by heating and bending a straight glass tube into a U-shape with a plurality of straight sections and a 180.degree.-bend. Adequate vessel wall thickness is assured at the tubular sections where the bends are formed, by first heating a central section, moving sections lateral to the central section axially toward one another, thereby compressing the heated central section and thickening its walls, and bending or rotating the lateral sections into a parallel orientation. This prevents the bending process from unduly thinning the vessel walls, leading to breakage or rupture under internal gas pressure.

Method of making a discharge vessel for compact low-pressure discharge

To reduce the operating temperature of a U-shaped or multiple U-bent fluocent lamp, the respective longitudinal and transverse sectional elements of the U-shaped lamp are so related that the outer generating line M.sub.Q of the individual transverse tube sections (4; 20, 21, 22) is substantially straight;

Low-pressure mercury vapor discharge lamp, particularly U-shaped

High pressure mercury vapor discharge lamp having an outer bulb which is ferably spherical and which provides light having a color similar to that of an incandescent lamp. The inner surface of the outer bulb is provided with a red-emitting phosphor coating. The outer surface of the outer bulb is provided with a filter coating whose transmittance at 400 nm is about 40%, at 500 nm is about 60%, and at 600 nm is about 70%.

Growing community of inventors

Augsburg, Germany

Lutz Klein