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Low Dark Resistance Photoconductor

IP.com Disclosure Number: IPCOM000098228D
Original Publication Date: 1960-Apr-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

O'Connell, JA: AUTHOR [+2]

Abstract

When a standard low dark resistance is required, a photoconductor is overlaid with a tin oxide surface film which forms a parallel resistance without optical interference.

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Low Dark Resistance Photoconductor

When a standard low dark resistance is required, a photoconductor is overlaid with a tin oxide surface film which forms a parallel resistance without optical interference.

A regenerative electroluminescent lamp photoconductor (EL-PC) device which depends on a low resistance PC for non-linear characteristics is shown in the top drawing. The corresponding schematic is at the lower right. Glass plate 1 is coated with a transparent conductive layer 2 which may be tin oxide. EL layer 3 covers layer 2 and is in turn covered by insulator layer 4 except at a small hole 5. PC 6 is deposited over insulator 4 and through hole 5 where it makes series connection with EL layer 3. The assembly is heated to 375 degrees 425 degrees. Tin chloride solution is sprayed over the PC and further heated in air until transparent tin oxide layer 7 forms.

A brightness voltage curve is at the lower left. The EL phosphor layer becomes luminant as the potential between terminals 8 and 9 surpasses threshold level 10. The EL becomes brighter as potential increases, and finally latches in the bright state as optical feedback from EL to PC becomes regenerative at point 11. Further increase of potential beyond point 12 has little effect. Reduction of potential has little effect above point 13 at which regeneration ceases and brightness fades to point 14. The transparent tin oxide resistance biases the device at point 14 of hysteresis loop 11, 12, 13, 14. A voltage...