U.S. Philips Corporation

Koninklijke Philips Corporation N.V.

Rolf E De Man

Peter Hubertus Franciscus Deurenberg

Franciscus A Ligthart

Christianus J Roozekrans

Dick Van Der Voort

Leo M Sprengers

Lambertus J Bouwman

Jan De Ridder

Theodorus Maria Hendriks

Arjan J Van Den Berg

Jozef I Peeters

Low-pressure mercury vapor discharge lamp comprises a light-transmitting discharge vessel () enclosing, in a gastight manner, a discharge space () provided with a filling of mercury and a rare gas. The discharge vessel comprises discharge means () for maintaining a discharge in the discharge space. The discharge vessel is provided with a container comprising an amalgam (). The container is provided with releasing means () for the controlled release of mercury vapor from the amalgam. The releasing means is open during lamp operation and is substantially closed when, during lamp operation, the temperature of the amalgam becomes higher than a pre-determined temperature. Preferably, the pre-determined temperature corresponds to a temperature of a range of temperatures at which the mercury-vapor pressure above the amalgam is relatively stable.

Low-pressure mercury vapor discharge lamp

A circuit arrangement for supplying a discharge lamp with a direct current includes input terminals for connection to a supply voltage source. A circuit portion (I) is coupled to the input terminals for generating a DC voltage from the supply voltage and is provided with output terminals between which the DC voltage is present during operation. A first branch comprising a first capacitor interconnects the output terminals and a second branch comprising a series arrangement of a second capacitor and an impedance shunts the first branch. A load branch shunts the series arrangement and comprises terminals for connecting a discharge lamp. The second branch also includes a diode so that a discharge lamp operated by way of the circuit arrangement stabilizes satisfactorily after ignition by a current supplied by the second capacitor to the lamp via the impedance.

Ignition circuit for a discharge lamp

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

An arrangement including a frequency converter (4) and a discharge lamp (10) connected thereto wherein the frequency converter (4) is of a type whose output frequency is at least 80 kHz, while the lamp is a low-pressure sodium vapor discharge lamp. This lamp supply system provides a high luminous efficacy for the lamp.

Arrangement including a metal vapor discharge tube provided with at

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Eindhoven, Netherlands

Rolf E De Man