U.S. Philips Corporation

Johannes H Van Der Sande

Johannes T De Hair

Robertus A Keijser

Ronald J Campbell

Franciscus G Sools

Monique M Eerdekens

Klaas Vegter

The invention relates to a high-pressure sodium discharge lamp which under nominal operating conditions radiates white light with a maximum color rendering index R.sub.a of more than 80. Since the wall load is above 80 W/cm.sup.2 under nominal operating conditions, a color temperature T.sub.c of at least 2800.degree. K. can be achieved with a luminous efficacy of more than 40 lm/W.

High-pressure sodium discharge lamp having a color temperature of at

A high-pressure sodium discharge lamp having a nominal power of at most 50 W provided with an elongate ceramic lamp vessel, which has over a length L an at least substantially constant inner diameter .phi. and a substantially constant wall thickness d, in which discharge vessel electrodes are arranged with their tips opposite to each other at a relative distance D. During operation, the lamp emits light having a color temperature of at least 2250K. According to the invention, it holds that D/L.ltoreq.0.5 and (.phi.+d).ltoreq.2.5 mm, while the discharge vessel is in mechanical contact with a substantially radially extending molding.

High-pressure sodium discharge lamp with fins radially extending from

The invention relates to a high-pressure discharge lamp for use in the vertical position, having a tubular ceramic discharge vessel, the electrodes being connected to current lead-through members which have been provided one at each end of the discharge vessel, a first, upper current lead-through member consisting of material which is resistant to attack by halogens and/or halides, for example molybdenum, and a second, lower current lead-through member comprising a hydrogen-permeable material, for example niobium.

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Eindhoven, Netherlands

Johannes H Van Der Sande