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US 3,947,719 AGranted
Filtered fluorescent lamp
AssigneeJohn Ott Laboratories, Inc.
InventorJohn Nash Ott
Life of this patent
Estimating the term…
Abstract
A light filtering system for improving the spectral output from fluorescent lamps. A filter placed within the lamp envelope between the phosphor coating and the arc discharge path between the lamp electrodes, absorbs mercury arc radiation in the visible range while passing arc radiation in the ultraviolet range to excite the phoshor coating and produce visible light emitted through the outer envelope.
Claims4
In a fluorescent lamp the combination comprising:;
- a. an envelope having a phosphor coating thereon,
- b. an ionizable medium within said envelope,
- c. a pair of electrodes mounted within said envelope between which an arc discharge occurs upon operation of the lamp, and
- d. filtering means arranged to extend between said phosphor coating and the path of said arc discharge, said filtering means comprising a material which has an internal transmittance with respect to arc radiation passing therethrough of not less than 70 percent in the ultraviolet phosphor-excitation range and not more than 40 percent in the visible range whereby the filtering means passes ultraviolet radiation from said arc discharge which excites said phosphor coating to produce visible light while substantially attenuating radiation from said arc discharge in the visible range which would otherwise cause spectral distortion in the light output of the lamp.
1 more element
Dependencies are inferred from the claim text.