Apparatus for controlling an electrochromic device
US5978126A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 21, 1998 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Sep 21, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/163
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An apparatus for controlling a charge state of an electrochromic devices according to the invention, where the electrochromic devices receives a charging current, comprises: a reference impedance, coupled to receive a reference current proportional to the charging current, the reference impedance having a known impedance relationship with the electrochromic device; a comparator, coupled to the reference impedance, for comparing a voltage level of the reference impedance to a threshold voltage level and producing an output signal indicative of the comparison; and control logic, coupled to the comparator, for simultaneously adapting the reference current and the charging current in response to the output signal of the comparator. In one embodiment of the invention, the apparatus is included within a pair of eyeglasses.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.