Enhanced vision system implemented with optical shutter alternately transmitting visible radiation and near infrared radiation
US9229139B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 17, 2014 |
| Grant date | Jan 5, 2016 |
| Priority date | — |
| Expiry date | Jul 17, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N23/55
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical shutter employed in an enhanced vision system includes a wavelength selective polarizing filter in optical association with a liquid crystal polarization modulator to rapidly switch between optical states to alternately transmit visible (VIS) radiation and near infrared (NIR) radiation. The wavelength selective polarizing filter imparts a polarization state to incident radiation and transmits polarized radiation within at least the visible wavelength region. The liquid crystal polarization modulator receives incident radiation for internal propagation through the modulator and responds to first and second values of an applied control signal to switch the internally propagating radiation to, respectively, first and second polarization states. The switching between first and second polarization states produces, in cooperation with the wavelength selective polarizing filter, optical shutter output VIS and NIR radiation. A computer processes the output VIS and NIR radiation to produce for display a composite image formed of visible and infrared elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.