Power outage indicator

Details Power outage indicator Power outage indicator

1982-02-11

1984-10-23

Rowland, James L.

Communications: electrical

Condition responsive indicating system

Specific condition

340765, 340784, 350350S, G08B 2100

Patent

active

044791186

ABSTRACT:
A power outage indicator utilizes a smectic liquid crystal display cell, capable of storing information indefinitely, to provide a visual indication, of predetermined form, that power to a given installation has been interrupted. Prior to installation, the smectic liquid crystal display of the power outage indicator is heated and an appropriate voltage placed between the display electrodes to cause the liquid crystal material to align homeotropically, as the liquid crystal material cools to the smectic state; a clear stable texture results. Upon loss of power, stored charge, as in a storage capacitor, is enabled to flow through at least a portion of at least one of the display electrodes, reheating the liquid crystal material therebetween and, upon cooling without an applied field, converts a portion of the liquid crystal layer to a state having differing light-propagation properties than the remainder of the display. The resulting "message" remains visible on the indicator until the indicator is reset by reheating in the presence of an applied field.

REFERENCES:
patent: 3204193 (1965-08-01), Rhyne, Jr.
patent: 4196974 (1980-04-01), Hareng et al.
patent: 4346375 (1982-08-01), Billings
patent: 4371870 (1983-02-01), Biferno
patent: 4385807 (1983-05-01), Perbet et al.

Affiliated with

Also associated with

Rating

Power outage indicator does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Power outage indicator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Power outage indicator will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1601485