Richard D Turner

US Patent:

55612873, Oct 1, 1996

Filed:

Sep 30, 1994

Appl. No.:

8/316521

Inventors:

Richard M. Turner - Boulder CO
Kristina T. Johnson - Longmont CO
David A. Jared - Mountain View CA

Assignee:

Board of Regents of the University of Colorado - Boulder CO

International Classification:

G01J 142

US Classification:

2502082

Abstract:

A semiconductor device comprising a dual photodetector for use in an array to locate points of peak intensities incident upon the array. Each pixel in the array is comprised of a dual photodetector element. An n-type well is located within a p-substrate with highly doped p-contact areas located along the periphery of the n-well at the surface. A metal or polysilicon gate electrode covers the surface between the p-contacts and an applied gate voltage creates an inverted p-channel to form a lateral effect phototransistor. A second photodetector is formed at the junction of the n-well and p-substrate. The second photodetector from each pixel produces a current which is connected to a processing circuit to determine which pixel is the brightest above a designated threshold. All pixels above the threshold are sequentially identified. For the "bright" pixels, photogenerated currents produced by the lateral effect phototransistors are analyzed by another processing circuit to produce the points of peak intensity within the bright pixel areas.