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Self-Compensation Circuits of Light-Emitting Diode Brightness

IP.com Disclosure Number: IPCOM000043994D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 20K

Publishing Venue

IBM

Related People

Matino, H: AUTHOR

Abstract

Uniform brightness and improved print quality for light-emitting diode (LED) arrays is achieved by self-compensation circuits for tandem structure devices consisting of LEDs and Schottky barrier (SB) detector diodes. The light emitted from the LED arrays passes through the SB layer, where the amount absorbed depends upon the atomic contents or thickness of the window material. In the circuit configuration shown, the SB diode 11 forms a negative feedback loop in which the impedance of the SB diode 11 is modulated by the brightness of LED 12. As the brightness of the LED 12 increases, the SB diode 11 impedance decreases, thus reducing the LED's brightness. It is necessary to first reduce the LED 12 current by negative feedback.

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Self-Compensation Circuits of Light-Emitting Diode Brightness

Uniform brightness and improved print quality for light-emitting diode (LED) arrays is achieved by self-compensation circuits for tandem structure devices consisting of LEDs and Schottky barrier (SB) detector diodes. The light emitted from the LED arrays passes through the SB layer, where the amount absorbed depends upon the atomic contents or thickness of the window material. In the circuit configuration shown, the SB diode 11 forms a negative feedback loop in which the impedance of the SB diode 11 is modulated by the brightness of LED
12. As the brightness of the LED 12 increases, the SB diode 11 impedance decreases, thus reducing the LED's brightness. It is necessary to first reduce the LED 12 current by negative feedback.

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