Light-operated proximity detector with linear output

Patent · Tue Jan 01 04:00:00 EST 1985

OSTI ID:865448

Simpson, Marc L ^[1]; McNeilly, David R ^[2]

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1. Harriman, TN
2. Maryville, TN

A light-operated proximity detector is described in which reflected light intensity from a surface whose proximity to the detector is to be gauged is translated directly into a signal proportional to the distance of the detector from the surface. A phototransistor is used to sense the reflected light and is connected in a detector circuit which maintains the phototransistor in a saturated state. A negative feedback arrangement using an operational amplifier connected between the collector and emitter of the transistor provides an output at the output of the amplifier which is linearly proportional to the proximity of the surface to the detector containing the transistor. This direct proportional conversion is true even though the light intensity is varying with the proximity in proportion to the square of the inverse of the distance. The detector may be used for measuring the distance remotely from any target surface.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN
• DOE Contract Number: W-7405-ENG-26
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4516020
• OSTI ID: 865448
• Country of Publication: United States
• Language: English

Related Subjects

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amplifier
amplifier connected
arrangement
circuit
collector
connected
containing
conversion
described
detector
detector circuit
detector containing
direct
direct proportion
directly
distance
emitter
feedback
feedback arrangement
gauged
intensity
inverse
light
light intensity
light-operated
light-operated proximity
linear
linearly
maintains
measuring
negative
negative feedback
operational
operational amplifier
output
phototransistor
proportion
proportional
provides
proximity
proximity detector
reflected
reflected light
remotely
saturated
sense
signal
signal proportional
square
surface
target
target surface
transistor
translated
true
varying