Patent ID: 6101750
Filing Date: 2000-08-15
Classification: G09F

Abstract:
An electrically operated sign system for displaying a time variable message over a full range of ambient light levels comprising:(a) a sign panel for displaying said message, said sign panel comprising a plurality of character matrices arranged in rows and columns in the panel and wherein each of said character matrices further comprises an array of pixels arranged in rows and columns which may be selectively used to define a character;(b) wherein said sign panel includes a shuttered system for displaying said message including non-polarizing electro-optic shutters, one shutter for each pixel, said shutters operable between a high light transmitting open state and a low light transmitting closed state and a reflecting surface behind each said shutter for reflecting ambient light received through said electro-optic shutter in said open state back through said shutter;(c) wherein said sign panel further includes a shutterless system independent of said shutter system for displaying said message using artificial lighting devices, wherein said artificial lighting devices are located alongside of said electro-optic shutters and include for each pixel at least one low power artificial lighting device;(d) an electrical energizing system connected to selectively operate said electro-optic shutters of said shuttered system and said artificial lighting devices for said shutterless system; and(e) a control system for selectively causing said sign panel to display said message by using a system for displaying said message from the group consisting of said shuttered system and said shutterless system in a manner such that said message can be displayed over a full range of ambient light levels with low power consumption.