U.S. Philips Corporation

Frans J Traksel

Antonius J Spaapen

Bauke J Roelevink

Johannes A Van Heeswijk

Frank Gerardus Cornelis De Bot

William Lodewijk Kuijer

Johannes A G Van Dongen

Jacobus P Van As

A method of manufacturing a low-pressure mercury vapor discharge lamp starting from a discharge vessel (,) wherein a closed holder (,) is placed which is provided with a quantity of one or more substances to be introduced in the discharge vessel (,). Subsequently, a desired gas atmosphere is brought about in the discharge vessel (,) and the discharge vessel is closed. Finally, the holder (,) is opened. According to the invention, the holder (,) is made from a leadoxide containing glass, which leadoxide is partly reduced and in which the amount of reduction is a measure of the mercury content of the holder (,). Due to the reduction process holders (,) with different mercury contents have a different color.

Low pressure mercury discharge lamp having a mercury holder with reduced lead oxide

A capsule (20) having a glass wall (21) and containing mercury is positioned in a radiation-transmitting discharge vessel, after which the discharge vessel is provided with a rare gas and closed, means for maintaining an electric discharge are arranged in or adjacent the discharge vessel. The capsule is opened by fusion after the discharge vessel has been closed by heating the capsule by irradiation (42) with a parallel beam of radiation through the wall of the discharge vessel. The wall of the capsule has for this radiation an absorption coefficient which amounts at least ten times that of the wall portion of the discharge vessel.

Method of manufacturing a low-pressure mercury discharge lamp

In a method according to the invention, a capsule (20) having a glass wall (21) and containing mercury is positioned in a radiation-transmitting discharge vessel, after which the discharge vessel is provided with a rare gas and closed, means for maintaining an electric discharge are arranged in or adjacent the discharge vessel, and the capsule is opened by fusion after the discharge vessel has been closed in that the capsule is heated by irradiation (42) with a parallel beam of radiation through the wall of the discharge vessel. The wall of the capsule has for this radiation an absorption coefficient which amounts at least ten times that of the wall portion of the discharge vessel. The method according to the invention renders possible a comparatively simple lamp construction. A low-pressure mercury discharge lamp is provided with a radiation-transmitting discharge vessel (10) which is closed in a gastight manner and has an ionizable filling comprising mercury, while a capsule (20) with a glass wall (21) having an opening (24) is arranged in the discharge vessel, and the lamp is in addition provided with means (31A, 31B) for maintaining an electric discharge in a discharge space (13) surrounded by the discharge vessel. The capsule (20) is accessible to radiation of at least a wavelength lying in a range from 100 nm to 5 .mu.m from outside the discharge vessel (10) through a wall portion (11) thereof, and the wall (21) of the capsule (20) has an absorption coefficient for this radiation which amounts at least ten times that of the wall portion (11) of the discharge vessel.

Low-pressure mercury discharge lamp having mercury capsule with a

The low-pressure discharge lamp has a tubular lamp vessel provided at its both ends with a lamp cap having a pair of contact pins. Each lamp cap is fixed in an adapter having one central contact pin electrically connected to at least one of the pair of contact pins of the lamp cap. A lamp of ordinary construction when provided with the adaptor is thus suitable for use in a space containing explosive gas.

Adaptor for a low-pressure discharge lamp

Mercury is dosed into a fluorescent or similar lamp from a container shaped mostly as an elongated flat plate, inserted lengthwise into the exhaust tube and held in place by a rib in the tube engaging depressions in the center of the plate. To permit easy insertion, the end of the plate opposite the mercury container has a relatively large through hole, leaving a thin resilient wall on each side of the hole so that insertion force is minimized.

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Roosendaal, Netherlands

Frans J Traksel