Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group

Photoelectric Measurement of Scale Marks and Spectrum Lines

Not Accessible

Your library or personal account may give you access

Abstract

A new type of all-electric balancing network for photometric purposes is described, with which a single photo-tube or electron multiplier can be used to locate rapidly the center of a scale mark or spectrum line. This device is now in use on two automatic measuring engines, and is found to give results more reproducible than those involving setting by eye. It is far simpler to adjust and to use than the balanced-cell method previously described. As the enlarged image of a line passes at uniform speed across a slit behind which the multiplier is placed, the variation in light intensity produces a variable output current. The resulting voltage is applied after amplification to a delay network designed to give uniform delay and attenuation to all signals of frequency between 0 and 200 cycles per second. Input and output of this network are combined in phase which is opposite except for the delay, so that the voltage at any instant is balanced against the voltage produced 13 milliseconds previously. Thus, with proper mechanical delay, densities at points on a plate separated by as little as 20 microns can be compared, and a sharp signal is obtained at a position corresponding to the passage of the peak of a line across the slit. This pulse is used to fire a stroboscopic lamp which records instantaneously the reading of a dial which measures the position of the plate. Plates are usually scanned at 4 mm per second, and the positions of as many as 4000 lines can be recorded to within 1 micron or less in 120 seconds.

© 1940 Optical Society of America

Full Article  |  PDF Article
More Like This
An Improved High Speed Recording Spectrophotometer

George R. Harrison and Edward P. Bentley
J. Opt. Soc. Am. 30(7) 290-294 (1940)

A Photoelectric Color Temperature Meter for Incandescent Lamps

M. H. Sweet
J. Opt. Soc. Am. 30(11) 568-571 (1940)

A Multipurpose Photoelectric Reflectometer

Richard S. Hunter
J. Opt. Soc. Am. 30(11) 536-559 (1940)

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Figures (4)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Equations (1)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Select as filters


Select Topics Cancel
© Copyright 2024 | Optica Publishing Group. All Rights Reserved