LED COLOR INFORMATION DISPLAY BOARD

PURPOSE:To realize accurate color expression, and prevent the confusion of an observer, by corresponding with the change of a forward direction voltage due to the environmental temperature of an LED which emits one color in a picture element, and controlling the current of an LED which emits the oth...

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Bibliographic Details
Main Authors KAMIKAWA TOSHIMI, ITO SHINICHI
Format Patent
LanguageEnglish
Published 22.08.1995
Edition6
Subjects
ADVERTISING
ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICESUSING STATIC MEANS TO PRESENT VARIABLE INFORMATION
BASIC ELECTRIC ELEMENTS
CRYPTOGRAPHY
DISPLAY
EDUCATION
ELECTRIC COMMUNICATION TECHNIQUE
ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
ELECTRICITY
PHYSICS
PICTORIAL COMMUNICATION, e.g. TELEVISION
SEALS
SEMICONDUCTOR DEVICES
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Summary:PURPOSE:To realize accurate color expression, and prevent the confusion of an observer, by corresponding with the change of a forward direction voltage due to the environmental temperature of an LED which emits one color in a picture element, and controlling the current of an LED which emits the other color. CONSTITUTION:A voltage measuring circuit 26 is connected between the anode and the cathode of a green color LED 4G (or a blue color LED 4B), measures the forward direction voltage, and operates the correction value. The output of the voltage measuring circuit 26 is inputted in a programable constant current circuit 25. By the correction value on the basis of the forward direction voltage of the green color LED 4G, the value of a current applied to the red color LED 4R is controlled so as to obtain adequate brightness. For example, when a picture element 311 is selected by a driver circuit 21, the forward direction voltage of an LED 4G11 which emits light as the result of the selection is measured, and the luminance for a red LED 4R11 is corrected.
Bibliography:Application Number: JP19940037509