US4521077A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light transmitting window assembly
Assignee: National Aeronautics and Space Administration
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Filing: 1983-08-16
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Granted: 1985-06-04
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Expires: 2003-08-16
Abstract
Abstract This invention provides a light transmitting assembly that can, at will, be changed from a state of transparency to one of translucency. It comprises two parallel spaced apart panes of transparent material, such as glass, with a film of polytetrafluoroethane, which is inherently translucent or opaque, disposed between. The assembly is rendered transparent by introducing a fluid into the assembly to substantially cover a surface of the film; the fluid having a refractive index corresponding to the refractive index of the film. The translucency is restored by removing the fluid.
Inventors
- 👤 Dale L. Connelly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:41
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/20; G02B5/22; G02B5/24; E; E06; E06B; E06B3/00; E06B3/66; E06B3/67; E06B3/6715; E06B3/6722; E06B9/00; E06B9/24; E06B2009/2411
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
57 words
A light transmitting assembly comprising parallel spaced apart panes of transparent material with a film of polytetrafluoroethylene affixed between said panes, means to substantially coat at least one surface of said film with a fluid having a refractive index approximately equal to that of said film to render said film transparent and means to remove said fluid.
Claim 2
Dependent Claim
57 words
A light transmitting assembly comprising parallel spaced apart panes of transparent material with a film of polytetrafluoroethylene affixed between said panes, means to substantially coat at least one surface of said film with a fluid having a refractive index approximately equal to that of said film to render said film transparent and means to remove said fluid.
Claim 3
Dependent Claim
13 words
The light transmitting assembly of claim 1, wherein the transparent material is glass.
Claim 4
Dependent Claim
23 words
The light transmitting assembly of claim 2, wherein the fluid has a refractive index in the range of from about 1.30 to 1.40.
Claim 5
Dependent Claim
16 words
The light transmitting assembly of claim 3, wherein the fluid is acetone, isopropyl alcohol or trichlorotrifluoroethane.
Claim 6
Dependent Claim
20 words
The light transmitting assembly of claim 4, wherein the film of polytetrafluoroethane is coextensive with the panes of transparent material.
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) | 1988-06-03 | 1988-12-03 | 1989-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-03 | 1992-12-03 | 1993-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-03 | 1996-12-03 | 1997-06-04 | $7700.00 | Window Closed / Lapsed |