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Title: Flash protection controller

Abstract

A controller provides a high voltage to maintain an electro-optic shutter in a transparent condition until a flash of light which would be harmful to personnel is sensed by a phototransistor. The controller then shorts the shutter to ground to minimize light transmission to the user and maintains light transmission at the pre-flash level for a predetermined time to allow the flash to subside. A log converter and differential trigger circuit keep the controller from being triggered by other light flashes which are not dangerous.

Inventors:
 [1]
  1. Mountain View, CA
Issue Date:
Research Org.:
Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
OSTI Identifier:
863946
Patent Number(s):
4282429
Assignee:
United States of America as represented by United States (Washington, DC)
Patent Classifications (CPCs):
G - PHYSICS G02 - OPTICS G02F - DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH IS MODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THE DEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY, COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g. SWITCHING, GATING, MODULATING OR DEMODULATING
DOE Contract Number:  
AT(29-1)-789
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
flash; protection; controller; provides; voltage; maintain; electro-optic; shutter; transparent; condition; light; harmful; personnel; sensed; phototransistor; shorts; ground; minimize; transmission; user; maintains; pre-flash; level; predetermined; time; allow; subside; log; converter; differential; trigger; circuit; triggered; flashes; dangerous; trigger circuit; light transmission; predetermined time; ash level; controller provides; determined time; /250/

Citation Formats

Galbraith, Lee K. Flash protection controller. United States: N. p., 1981. Web.
Galbraith, Lee K. Flash protection controller. United States.
Galbraith, Lee K. Thu . "Flash protection controller". United States. https://www.osti.gov/servlets/purl/863946.
@article{osti_863946,
title = {Flash protection controller},
author = {Galbraith, Lee K},
abstractNote = {A controller provides a high voltage to maintain an electro-optic shutter in a transparent condition until a flash of light which would be harmful to personnel is sensed by a phototransistor. The controller then shorts the shutter to ground to minimize light transmission to the user and maintains light transmission at the pre-flash level for a predetermined time to allow the flash to subside. A log converter and differential trigger circuit keep the controller from being triggered by other light flashes which are not dangerous.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1981},
month = {1}
}