Low power phototransistor-based welding helmet providing reduced sensitivity to low intensity light and sharp phototransistor response to high intensity light
US7005624B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 10, 2005 |
| Grant date | Feb 28, 2006 |
| Priority date | — |
| Expiry date | Feb 10, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J2001/0276
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An auto darkening eye protection device including a shutter assembly, a light sensing circuit, a control circuit and a power supply source. The shutter assembly is adjustable to a plurality of shade levels. The phototransistor of the light sensing circuit senses light from a welding arc and provides an output of the light sensing circuit indicative of the shade level at which the shutter assembly should be operated. The phototransistor is configured for surface mount and has an external base connection connected to the base of the phototransistor. The control circuit is configured to receive the output from the light sensing circuit and provide a drive signal to the shutter assembly responsive to said output, drives the shutter assembly to one of said plurality of shade levels. The present invention provides reduced power consumption, improved attenuation of low intensity light signals, a sharp rise time from the phototransistor in response to high intensity light, and allows implementation into a smaller sleeker eye protection device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.