Position sensing with photodiodes

Two complementary technologies allow system optimization for optical-beam centering and/or quantitative measurement of lateral beam displacement. Position-sensing photodiodes provide quantitative information about the position of an incident light beam or spot image.

Feb 1st, 2002
Th 84742

FIGURE 1. The most common multielement photodiodes used for position-sensing applications are the bi-cell and quad-cell.
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Two complementary technologies allow system optimization for optical-beam centering and/or quantitative measurement of lateral beam displacement.

Position-sensing photodiodes provide quantitative information about the position of an incident light beam or spot image. These photodiodes have been in use for many years and as optical technology continues to find increasing application in areas as diverse as telecommunications, biomedicine, data storage, manufacturing, test and measurement, and aerospace/military, the need for these workhorse devices will likely continue to thrive.

Two technologies are currently used for position sensing: multielement photodiodes and position-sensing (or lateral-displacement) photodiodes.

Jeff Hecht,Contributing Editor

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