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US3591841A Expired / Lapsed US ⏱️ 0.0 years remaining

Optical device for determining extent of movement

Assignee: Ernst Leitz Wetzlar GmbH
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Filing: 1969-01-24
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Granted: 1971-07-06
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Expires: 1989-01-24
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Abstract

Abstract An apparatus for measuring the linear or angular movement of an object being provided with two graduation carriers movable relative to one another; one of the carriers being connectable to the object to be measured, the other one being connectable to a reference body. The apparatus further comprises means for illuminating one of the graduation carriers, means for projecting an image of the illuminated carrier on the other carrier, photoelectric means for sensing the carriers, and electronic evaluation means for processing the signals from the photoelectric means so as to provide output signals usable for digital indication or for control purposes. The first of the two graduation carriers having linear graduations comprising transparent or reflective striplike marks, the ratio of the graduation interval to the mark width corresponding, in the direction of the relative movement, to the desired number of interval fractions per graduation interval, and the second graduation carrier having one or a plurality of sensing fields the number of which is less than the desired number of interval fractions and which together form a combination of image patterns, each of these sensing fields having a plurality of striplike, light-permeable and light-impermeable portions of its surface area which are parallel with the marks of the first graduation carrier and which are unequal inter se in such a way that, upon relative movement of the graduation carriers over a distance corresponding to a graduation interval, different combinations of image patterns are produced which correspond in number to the desired number of interval fractions per graduation interval.

Inventors

  • 👤 Knut Heitmann
  • 👤 Eckart Schneider
  • 👤 Ludwig Leitz

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-26 07:37
CPC Classifications
H; H03; H03M; H03M1/00; G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/347; G01D5/34776; G01D5/34792; H03M1/10; H03M1/1009

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 292 words
In an optical measuring device for determining and digitally indicating the extent of movement of an object relative to a reference structure, a plurality of integrated sensing units, each sensing unit comprising first and second optically aligned graduation carriers, said first graduation carrier being secured to the reference structure, each said graduation carrier being provided with parallel linear graduations in the form of light permeable and light impermeable markings, the number of light impermeable markings per unit length on one carrier being unequal inter se to the number of light impermeable markings per unit length on the other carrier, the arrangement of the linear graduations permitting the light permeable markings on the first graduation carrier to be optically aligned with the light permeable markings on the second graduation carrier only when the first graduation carrier has been displaced relative to the second graduation carrier by a predetermined number of division units or a full numbered multiple of that number of division units, continuous illumination means adjacent said first graduation carrier optically aligned with said first and second graduation carriers for directing light through the light permeable marking of the second graduation carrier when they are optically aligned with the light permeable markings of the first graduation carrier, photoelectric means optically aligned with the illumination means and the first and second graduation carriers to sense the presence of a continuous transmission of light through both said graduation carriers and generating an electrical signal in response to the presence of light, and electronic evaluating means connected to said photoelectric means for processing the presence or absence of an electric signal generated thereby to provide a digital output signal usable for digitally indicating the extent of movement of the object relative to the reference structure.
Claim 2
Dependent Claim 292 words
In an optical measuring device for determining and digitally indicating the extent of movement of an object relative to a reference structure, a plurality of integrated sensing units, each sensing unit comprising first and second optically aligned graduation carriers, said first graduation carrier being secured to the reference structure, each said graduation carrier being provided with parallel linear graduations in the form of light permeable and light impermeable markings, the number of light impermeable markings per unit length on one carrier being unequal inter se to the number of light impermeable markings per unit length on the other carrier, the arrangement of the linear graduations permitting the light permeable markings on the first graduation carrier to be optically aligned with the light permeable markings on the second graduation carrier only when the first graduation carrier has been displaced relative to the second graduation carrier by a predetermined number of division units or a full numbered multiple of that number of division units, continuous illumination means adjacent said first graduation carrier optically aligned with said first and second graduation carriers for directing light through the light permeable marking of the second graduation carrier when they are optically aligned with the light permeable markings of the first graduation carrier, photoelectric means optically aligned with the illumination means and the first and second graduation carriers to sense the presence of a continuous transmission of light through both said graduation carriers and generating an electrical signal in response to the presence of light, and electronic evaluating means connected to said photoelectric means for processing the presence or absence of an electric signal generated thereby to provide a digital output signal usable for digitally indicating the extent of movement of the object relative to the reference structure.
Claim 3
Dependent Claim 39 words
In an optical measuring device as claimed in claim 1, wherein the arrangement of linear graduations on the second graduation carriers of successive sensing units is larger in graduation by one measuring unit than on the first graduation carriers.
Claim 4
Dependent Claim 29 words
In an optical measuring device as claimed in claim 1, wherein said linear graduations have their longitudinal axes at right angles to the direction of movement to be measured.
Claim 5
Dependent Claim 32 words
In an optical measuring device as claimed in claim 1, wherein said photoelectric means comprises a photoelectric receiver positioned to consecutively sense the presence of light from a plurality of sensing units.
Claim 6
Dependent Claim 24 words
In an optical measuring device as claimed in claim 1, wherein an optical projection system is provided between the first and second graduation carriers.
Claim 7
Dependent Claim 20 words
In an optical measuring device as claimed in claim 4, wherein the optical projection system is a mirror optical system.
Claim 8
Dependent Claim 49 words
In an optical measuring device as claimed in claim 1, wherein the arrangement of the linear graduations is such that the image pattern resulting after relative movement of the graduation carriers is in the form of a single step code which is cyclic with the number of interval divisions.
Claim 9
Dependent Claim 30 words
In an optical measuring device as claimed in claim 1, wherein light conducting means are positioned adjacent the second graduation carrier to conduct the transmitted light to the photoelectric means.

References Cited (Backward Citations)

US2416968A Cited
US2886717A Cited
US2832259A Cited
US3014134A Cited
US3427463A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1974-07-05 1975-01-04 1975-07-06 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1978-07-05 1979-01-04 1979-07-06 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1982-07-05 1983-01-04 1983-07-06 $7700.00 Window Closed / Lapsed

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