Browse Prior Art Database

Avoiding End Effects in Imaging Arrays

IP.com Disclosure Number: IPCOM000036763D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Schlig, ES: AUTHOR

Abstract

A structure is disclosed which prevents two types of spurious output signals which originate at the edges of integrated charge-coupled optical imaging arrays such as time-delay and integration (TDI) arrays and frame transfer arrays. One type of spurious output results from the collection of excess photocharge in the first and last column of photosites due to stray light impinging on the substrate outside the region protected by an opaque stray-light shield and to dark charge originating outside the imaging array. The second type of spurious output results from the placement of the edges of the opaque light shield at the edges of the first and last imaging columns, which causes those columns to exhibit a different photosensitivity than the others in the array.

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Avoiding End Effects in Imaging Arrays

A structure is disclosed which prevents two types of spurious output signals which originate at the edges of integrated charge-coupled optical imaging arrays such as time-delay and integration (TDI) arrays and frame transfer arrays. One type of spurious output results from the collection of excess photocharge in the first and last column of photosites due to stray light impinging on the substrate outside the region protected by an opaque stray-light shield and to dark charge originating outside the imaging array. The second type of spurious output results from the placement of the edges of the opaque light shield at the edges of the first and last imaging columns, which causes those columns to exhibit a different photosensitivity than the others in the array.

The layout of a TDI imaging array according to the invention is shown in the figure, which represents a schematic plan view of the semiconductor chip showing only the CCD channels, isolation regions, diffusions and opaque light shield. Other layers, particularly the parallel and serial CCD gate electrodes, are omitted for clarity. Only the bottom of the first few and last few imaging columns and the beginning and end of the serial register are shown. The first and last column are referred to as dummy columns, while the others are called imaging columns. Photocharge and dark charge from the periphery is collected by the two dummy columns. The serial register begins with...