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Browse Prior Art Database

Optical Transducer

IP.com Disclosure Number: IPCOM000091215D
Original Publication Date: 1969-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Boburka, JM: AUTHOR [+4]

Abstract

Semiconductor diode 10 emits light at two distinct emission spectra when forward biased above a threshold voltage level Vt and when reverse biased in the Breakdown mode respectively. It also senses light when biased below the threshold level Vt and between the Reverse Breakdown region at substantially the same spectral frequency it emits when biased above level Vt.

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Optical Transducer

Semiconductor diode 10 emits light at two distinct emission spectra when forward biased above a threshold voltage level Vt and when reverse biased in the Breakdown mode respectively. It also senses light when biased below the threshold level Vt and between the Reverse Breakdown region at substantially the same spectral frequency it emits when biased above level Vt.

Diode 10 is a ternary compound of Group III and V elements such as GaAlAs. PN junction 11 is formed between opaque P layer 10a and transparent N layer 10b. Double-pole, double-throw switch 12 is connected to a power supply, e.g., battery 13 and adjustable resistor 14. With arms a of switch 12 closed with switch contacts I, diode 10 is reverse biased Rev. With arms a of switch 12 closed with the switch contacts II, diode 10 is forward biased Fwd.

When biased Fwd above level Vt, diode 10 operates in Emit region A of its operating characteristic curve and emits light at a given spectral frequency. When diode 10 is biased in the Sense region of curve A, i.e., between level Vt and the Breakdown region, it senses or detects light at the same last-mentioned spectral frequency. Reverse biasing diode 10 in the Breakdown region of A causes the diode to operate in its Emit' region and to provide a spectral frequency different from the spectral frequency associated with the Sense and Emit regions.

For example, GaAlAs diodes emit visible light in the red spectrum in the narrow range of 6700 angst...