US3809944A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low-pressure mercury vapour discharge lamp
Assignee: US Philips Corp
•
Filing: 1972-08-25
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Granted: 1974-05-07
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Expires: 1992-08-25
Abstract
Abstract An aperture lamp, especially for phototype purposes in which the glass in the aperture is coated with a conducting transparent coating having a resistance of between 5 and 200 kOhms. This coating does not only reduce blackening of the glass in the aperture but also decreases the ignition voltage considerably.
Inventors
- 👤 H Jongerius
- 👤 Der Wolf R Van
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:21
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/54; H01J61/545; H01J61/24; H01J61/26; H01J61/30; H01J61/35
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
118 words
A low-pressure mercury vapour discharge lamp having a cylindrical glass envelope which includes means for generating a discharge and whose inner side is coated with a coating of luminescent material over such a part of the circumference that a longitudinal aperture is free from said luminescent material, a coating consisting of titanium dioxide being provided between the glass envelope and the luminescent coating, which titanium dioxide coating reflects the radiation produced in the luminescent coating satisfactorily, the glass in the aperture being coated on the inner side with a transparent coating of a material reducing attack and blackening of the glass, the transparent coating, measured from end to end, having a resistance of between 5 and 200 kOhms.
Claim 2
Dependent Claim
29 words
A low-pressure mercury vapour discharge lamp as claimed in claim 2 wherein the transparent coating, measured from end to end, has a resistance of between 20 and 100 kOhms.
Claim 3
Dependent Claim
23 words
A low-pressure mercury vapour discharge lamp as claimed in claim 2 wherein the transparent coating in the aperture consists of conducting tin oxide.
Claim 4
Dependent Claim
23 words
A low-pressure mercury vapour discharge lamp as claimed in claim 2 wherein the transparent coating in the aperture consists of conducting indium oxide.
Claim 5
Dependent Claim
30 words
A low-pressure mercury vapour discharge lamp as claimed in claim 1, wherein the transparent coating extends over the entire circumference of the envelope and engages the glass at all areas.
Claim 6
Dependent Claim
39 words
A low-pressure mercury vapour discharge lamp as claimed in claim 2, wherein the transparent coating extends over the entire circumference of the envelope, the portion present outside the aperture being located between the reflection coating and the luminescent coating.
References Cited (Backward Citations)
US3067356A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-06 | 1977-11-05 | 1978-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-06 | 1981-11-05 | 1982-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-06 | 1985-11-05 | 1986-05-07 | $7700.00 | Window Closed / Lapsed |