Eye-protection device having dual high voltage switching
US6841772B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 3, 2002 |
| Grant date | Jan 11, 2005 |
| Priority date | — |
| Expiry date | May 3, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J2001/0276
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An auto darkening eye protection device comprising a shutter assembly and a control circuit. The shutter assembly is adjustable between a clear state and a dark state. The control circuit comprises a sensing circuit, a weld detect circuit, and a delivery circuit. The sensing circuit senses incident light and provides an output indicative of the incident light. The weld detect circuit receives the output of the sensing circuit, and enables a dark state drive signal to be delivered to the shutter assembly. The delivery circuit outputs the dark state drive signal to the shutter assembly to switch the shutter assembly from the clear state to the dark state upon enablement by the weld detect circuit. The dark state drive signal includes a high voltage pulse followed by a stable AC waveform. The high voltage pulse is formed by a positive voltage signal and a negative voltage signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.