Patent US3720827A successfully refreshed from Google Patents.
US3720827A
Expired / Lapsed
US
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Light transmitting foam plastic lenses
Assignee: Armstrong World Industries Inc
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Filing: 1970-12-28
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Granted: 1973-03-13
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Expires: 1990-12-28
Abstract
Abstract Foam plastic lenses may be used to form lenses for light fixtures. The voids in the lens tend to diffuse the light. By selectively affecting the voids in different areas of the lens, a wide range of unique patterns can be created from an otherwise uniform and visually and stylistically uninteresting foam sheet. Patterns are provided by embossing or vacuum forming the lens in selected portions.
Inventors
- 👤 J Hemphill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:37
CPC Classifications
F; F21; F21V; F21V3/00; F21V3/04
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
138 words
In combination, a luminaire with a light source therein and a lens positioned between the light source and an observer of the luminaire, said lens being formed of a foam, closed-cell plastic material, said cells having walls which form a plurality of interfaces to diffuse light coming from the light source, a pattern provided in at least one surface of the lens so as to change the thickness and other characteristics of the lens structure to provide the lens with a surface configuration which is depressed in the pattern areas, and said closed-cell structure is altered in the depressed areas to provide a cell structure which is enlarged over that of the cell structure of the nonpattern areas to provide for a light transmission characteristic in the pattern areas which is different from that of the nonpattern areas.
Claim 2
Dependent Claim
138 words
In combination, a luminaire with a light source therein and a lens positioned between the light source and an observer of the luminaire, said lens being formed of a foam, closed-cell plastic material, said cells having walls which form a plurality of interfaces to diffuse light coming from the light source, a pattern provided in at least one surface of the lens so as to change the thickness and other characteristics of the lens structure to provide the lens with a surface configuration which is depressed in the pattern areas, and said closed-cell structure is altered in the depressed areas to provide a cell structure which is enlarged over that of the cell structure of the nonpattern areas to provide for a light transmission characteristic in the pattern areas which is different from that of the nonpattern areas.
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) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |