U.S. Philips Corporation

Franciscus A Ligthart

Jean J Heuvelmans

Winston Donald Couwenberg

Bauke J Roelevink

Gustaaf A Wesselink

Christianus J Roozekrans

Dick Van Der Voort

Rolf E De Man

Jozef R Bergervoet

Robert C Peters

Patricius W Lepelaars

Louis E Vrenken

Albert Bouwknegt

Paulus Q Nederpel

Peter M Den Breeijen

Winston D Couvbenberg

Low-pressure mercury discharge meander lamp dimensioned for even

A lighting unit includes a discharge vessel having a wall provided with a first luminescent layer, a gas fill consisting essentially of neon at a pressure less than 30 mbar, and a means for providing a constant DC current for exciting the fill in the discharge vessel to emit UV light for exciting the luminescent layer. DC operation offers substantially higher luminous flux over AC operation. The lighting unit may further include a housing having a reflective surface, a second luminescent layer, and a filter incorporated within the discharge vessel.

Neon discharge lamp

A low-pressure mercury vapor discharge lamp according to the invention is provided with a discharge vessel (10) which encloses a discharge space (11) containing mercury and a rare gas in a gaslight manner. The discharge vessel (10) has a light-transmitting tubular portion (12) and a first and a second end portion (13A, 13B). Current supply conductors (20A, 20A'; 20B, 20B') issue through each end portion (13A, 13B) to respective electrodes (21A, 21B) arranged in the discharge space (11). The lamp is further provided with a main amalgam (30) for stabilizing the mercury vapour pressure in the discharge space (11) during normal operation, and with an auxiliary amalgam (31A, 31B) for quickly releasing mercury into the discharge space (11) after switching-on of the lamp. In an equilibrium state at room temperature (25.degree. C.), the mass (m.sub.Hg in mg) of the quantity of mercury absorbed in auxiliary amalgam (31A, 31B) is at most 20 times the mercury vapour pressure (P.sub.E in Pa) prevalent in the discharge space (11) in the equilibrium state. Only comparatively small brightness differences between lamp zones occur in the lamp according to the invention after switching-on.

Low pressure mercury vapor discharge lamp

A low pressure discharge lamp having a tubular discharge vessel (1). At each of its end portions (2, 3) the vessel (1) is fused to a respective metal tube (5) having an uncovered outer surface outside the vessel. A sealed glass tube (6) is fused to the metal tubes (5). Ignition aids (18, 28, 40) may also be present. The simple construction of the lamp permits manufacture and high lamp quality, even at long lengths and/or small diameters of the discharge vessel. The lamp may have an ionizable filling of rare gas or may also contain mercury. A fluorescent powder may also be present in the discharge vessel. The lamp (72) and a luminaire (70, 71) mounting the lamp may be used for display or signalling purposes.

Low-pressure discharge lamp and luminaire provided with such a lamp

An electrodeless low-pressure mercury vapor discharge lamp whose discharge vessel is provided with a core of magnetic material and a coil surrounding the core which coil connected to a high-frequency supply unit. An interference-suppressing, light transmissive electrically conductive layer is present on the outside of the discharge vessel, which layer can be connected to the supply mains through an electric conductor. The electric conductor comprises one or several capacitors connected in series to keep the conducting layer safe to touch during operation.

Electrodeless low-pressure mercury vapour discharge lamp

A low-pressure mercury vapour discharge lamp having a tungsten coil electrode which is supported at either end by a respective current supply wire and which has emitter-coated central turns and, on either side thereof, end turns which are free from emitter. Each of the current supply wire ends with adjoining end turns of the coil is surrounded by an electrically insulating sleeve, such as a glass tube, as a result of which the switching life of the lamp is considerably increased.

Low-pressure mercury vapor discharge lamp

Low-pressure mercury vapor discharge lamp having a curved discharge vessel in which a mercury discharge is maintained between the electrodes and in which furthermore an amlagam is provided to control the mercury vapor pressure, the discharge vessel containing a rare gas mixture which contains at least 50 at.% krypton at a pressure of 130 to 520 Pa.

Low-pressure mercury vapor discharge lamps provided with a luminescent layer and having a relatively high power consumption. Lamps are loaded by at least 500 W per m.sup.2 surface area of the luminescent layer. In some embodiments the lamps have a nominal length of 60 to 150 cm and consume a nominal power of 0.25 to 0.50 W per cm length of the discharge tube.

Low-pressure mercury vapor discharge lamp having a relatively small discharge vessel containing as the buffer gas a rare gas mixture which is rich in helium, but which also comprises a quantity of one or more heavier rare gases, preferably crypton. The heavier rare gases increase the arc voltage.

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Eindhoven, Netherlands

Franciscus A Ligthart