Browse Prior Art Database

Ac Operated Light Emitting Diodes

IP.com Disclosure Number: IPCOM000091217D
Original Publication Date: 1969-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Prusik, EW: AUTHOR [+2]

Abstract

Monolithic LED 10 has PN junctions 11 and 11' and operates with an AC biasing signal. Light emission occurs from junction 11 when forward biased by the appropriate half-cycle of the AC. Light emission occurs from junction 11'' when forward biased by the other half-cycle.

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Ac Operated Light Emitting Diodes

Monolithic LED 10 has PN junctions 11 and 11' and operates with an AC biasing signal. Light emission occurs from junction 11 when forward biased by the appropriate half-cycle of the AC. Light emission occurs from junction 11'' when forward biased by the other half-cycle.

Semiconductor body 10 consists of N center region 12 of GaAs and outer regions 13 and 14 of GaAlAs. Region 12 is the GaAs substrate on which the respective GaAlAs N layers a of regions 13 and 14 are formed by a solution epitaxial growth method. The respective P layers b form a PN junction with their respective N layers a, for example, such as by diffusion. Body 10 is coated with an opaque material except for frontal surface 10A from which light emits from the respective edges of junctions 11 and 11' which are parallel to surface 10A.

In operation, an AC 115 V, 60 cycle signal is applied across input terminals
15. Adjustable transformer 16 steps the AC down to a level sufficient to operate junctions 11 and 11' at respective forward bias levels which allows them to emit light alternately during each input cycle. Spacings S1 and S2 are selected so that, to an observer, viewing the alternate light emitting junctions 11 and 11' from face 10A, it appears that the light is emanating from LED 10 continuously from a common line source and without distortion. For example, typical dimensions S2 of GaAs substrate 12 are in a range of 10-15 mils, the corresponding dimensions ...