Patent US3947719A successfully refreshed from Google Patents.
US3947719A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filtered fluorescent lamp
Assignee: John Ott Laboratories Inc
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Filing: 1975-06-02
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Granted: 1976-03-30
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Expires: 1995-06-02
Abstract
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.
Inventors
- 👤 John Nash Ott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:40
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/38; H01J61/40
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
144 words
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.
Claim 2
Dependent Claim
144 words
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.
Claim 3
Dependent Claim
25 words
The fluorescent lamp of claim 1 wherein the filtering means comprises a tubular member arranged to surround the electrodes and the arc discharge path therebetween.
Claim 4
Dependent Claim
37 words
The fluorescent lamp of claim 1 wherein the envelope is formed of a material which transmits visible light while substantially attenuating radiation from the arc discharge in the ultraviolet range which is passed by the filtering means.
Claim 5
Dependent Claim
43 words
The fluorescent lamp of claim 1 wherein the ionizable medium comprises mercury vapor and the filtering means substantially attenuates mercury vapor radiation having a wave length greater than approximately 400 millimicrons while passing mercury vapor radiation having a wavelength less than 400 millimicrons.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-03-30 | 1979-09-29 | 1980-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-30 | 1983-09-29 | 1984-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-30 | 1987-09-29 | 1988-03-30 | $7700.00 | Window Closed / Lapsed |