Laser safety shutoff system
US4884275A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 24, 1988 |
| Grant date | Nov 28, 1989 |
| Priority date | — |
| Expiry date | Oct 24, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/042
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A safety light responsive shutoff switch is provided for a hand-held infrared laser light source to prevent irreparable eye damage to persons who may inadvertently look into the light exit opening of the laser light source while it is operating. This is accomplished by concentrically mounting normally-closed infrared light responsive photoelectric Darlington safety switches around the light exit end of the light source. Light reflected from the laser light source off an object intruding into the laser beam within a danger zone (typically zero inches to ten inches from the light exit opening) produces reflected light at the frequency of the laser light source of sufficient intensity to operate the photoelectric Darlington safety switch devices to turn off the power supply to the laser light source. Light reflected from objects which are outside of the danger zone is of insufficient intensity to operate the light responsive safety switches.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.