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Browse Prior Art Database

Elimination Of Crosstalk On EL X-Y Matrices

IP.com Disclosure Number: IPCOM000098076D
Original Publication Date: 1961-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Narken, B: AUTHOR

Abstract

The incorporation of a Cadmium Selenide (CdSe) layer in series with each electroluminescent element in an X-Y matrix is effective in suppressing crosstalk.

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Elimination Of Crosstalk On EL X-Y Matrices

The incorporation of a Cadmium Selenide (CdSe) layer in series with each electroluminescent element in an X-Y matrix is effective in suppressing crosstalk.

A series EL element and CdSe element combination at each X-Y intersection of a matrix is used in obtaining coincident selection. The application of a sufficient D. C. field (50 volts per/mil) across the CdSe polycrystalline material at the chosen intersection causes a periodic breakdown. The current waveform resembles a sawtooth and the I-V characteristic is very non-linear. The sawtooth current passes through the EL element causing a periodic field across its impedance and making the EL emit light. The series EL and breakdown element combination has a sharp non-linear brightness voltage characteristic. Crosstalk does not occur since the D. C. applied to the X-Y lines is not conducted through intersections and can not affect any EL which only responds to A.C.

An A. C. voltage of small magnitude may be superimposed on the D. C., instead of using pure D. C. voltage. The peak sum of the two voltages must be sufficient to break down the CdSe layer. The D. C. voltage now serves only to aid in breaking down the CdSe layer while the A. C, imparts the energy to light the EL. The magnitude of the A. C. signal, when coupled to the cross lines, is not great enough to break down the CdSe. Therefore, suppression on these lines is complete.

An A. C. voltage alone may be applied ac...