US 5,669,510 AGranted

Method and device for selecting low-pressure murcury discharge lamps

AssigneeU.S. Phillips Corporation

InventorsPetrus C. Lauwerijssen, Johannes T. W. De Hair, Lukas Kastelein, Henricus C. G. Verhaar

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Abstract

A method of selecting low-pressure mercury discharge lamps comprising a luminescent layer, the luminescent layer being excited and the low-pressure mercury discharge lamps being selected in dependence on the emission spectrum of the visible light emitted by the luminescent layer. The luminescent layer is excited by a light source arranged outside the low-pressure mercury discharge lamp and which generates ultraviolet radiation having a wavelength above 300 nm. This makes it possible to use the presence of a blue-luminescent substance in the luminescent layer as a selection criterion for both leaky and intact low-pressure mercury discharge lamps.

Claims6

Dependent claims

A method of selecting low-pressure mercury discharge lamps each comprising a discharge vessel provided with a luminescent layer on an inside surface thereof, said luminescent layer being excited and the low-pressure mercury discharge lamps being selected in dependence on the emission spectrum of the light emitted by the luminescent layer, said method comprising the steps of:

exciting the luminescent layer by ultraviolet radiation having a wavelength above 300 nm by directing the ultraviolet radiation to the discharge vessel from a location outside the low-pressure mercury discharge lamp,
measuring the intensity of the light emitted by the luminescent layer in a predetermined wavelength range;
and
associating each said lamp to a particular lamp group from among a plurality of lamp groups having respectively different luminescent layer compositions on the basis of the measured light intensity of said each lamp.

1 more element

Dependencies are inferred from the claim text.