Surveillance window
US7187498B2 · kind B2 · utility
167Cited by
27References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 28, 2002 |
| Grant date | Mar 6, 2007 |
| Priority date | — |
| Expiry date | May 28, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/28
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A surveillance window including at least one set of linear polarizer and quarter-waveplate and a reflecting surface. The surveillance window appears dull and opaque to a subject, while allowing a relatively high percentage of light to be transmitted to an observer. Various enhancements including an illuminator and detector, camouflaging, fire resistance, and improvements to the opacity are also described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.