Browse Prior Art Database

Yield Scan Array

IP.com Disclosure Number: IPCOM000081357D
Original Publication Date: 1974-May-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Thorpe, RA: AUTHOR

Abstract

In constructing large-scale integrated (LSI) arrays of photosensitive diodes for optical scanning functions, the topological yield of useful diodes is a significant factor. Nondefective arrays of diodes, to scan 512 points along a line corresponding to a scan line of 8 1/2 x 11 inch page, are obtainable from present manufacturing technology. However, when a four-fold increase in resolution is needed (2048 scan points), a requirement of nondefective array yield would be prohibitive.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 2

Yield Scan Array

In constructing large-scale integrated (LSI) arrays of photosensitive diodes for optical scanning functions, the topological yield of useful diodes is a significant factor. Nondefective arrays of diodes, to scan 512 points along a line corresponding to a scan line of 8 1/2 x 11 inch page, are obtainable from present manufacturing technology. However, when a four-fold increase in resolution is needed (2048 scan points), a requirement of nondefective array yield would be prohibitive.

Of course, four separate arrays of 512 detectors each may be arranged end- to-end for this purpose, but there would be problems of mechanical and optical alignment. Ideally for this purpose, the array should be implemented on a single substrate on a single chip. To avoid the yield problem, the chip should have redundancy of diodes and connection logic such that for each detection point, at least one operative photo-diode exists capable of providing a uniquely distinguishable signal.

This can be accomplished by providing an array topology of 2 x 2048 or 3 x 2048 diodes, Where the two or three diodes per scan point are physically neighboring and electronically cooperative to provide logical response to a single image point. When such an array has been tested, the defective photodiodes or other elements may be logically switched out of operation by conventional procedures for "bad bit" circumvention. The signals from the remaining elements of each point scan group nay the...