US3912926A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Opto-electronic incremental encoder
Assignee: LOS ANGELES SCIENTIFIC INSTRUMENT CO Inc
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Filing: 1974-10-18
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Granted: 1975-10-14
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Expires: 1994-10-18
Abstract
Abstract An opto-electronic incremental encoder for determining the amount and direction of shaft rotation, such as used in a planimeter, consisting of two discs each having two concentric annular arrangements of alternating transparent windows and opaque sections, two photodetectors, and light producing means. Both discs are of identical design with the exception of the central holes. Since one disc is fixed to the encoder body while the second is fixed to a shaft that rotates, the windows and opaque sections of each annular corresponding arrangement alternately transmit and block the light as the shaft rotates. The windows of the inner annular rings of each disc are offset one quarter of the angular width of the corresponding windows of the outer annular rings so that a quasi-sine wave from the first photodetector leads the quasi-sine wave generated by the second photodetector by about 90* when the shaft is turned in one direction and lags 90* when the shaft is rotated in the opposite direction. Electronic circuits process the signals to provide an increasing or decreasing count depending how the shaft is rotated.
Inventors
- 👤 Charles Coulbourn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:10
CPC Classifications
G; G01; G01P; G01P13/00; G01P13/02; G01P13/04; G01B; G01B11/00; G01B11/28; G01B11/285; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/36; G01D5/363; G01P3/00; G01P3/42; G01P3/44; G01P3/48; G01P3/481; G01P3/486
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
263 words
An opto-electronic incremental encoder comprising: a first disc stationarily mounted in an encoder body and a second disc, identical in design to said first disc, rotatably mounted on a shaft, the longitudinal axis of each disc coinciding with the longitudinal axis of said shaft, said first and second discs being positioned adjacent to each other; the first and second discs being provided with an identical outer annular arrangement of alternating transparent windows and opaque sections; the first and second discs being also provided with an identical inner annular arrangement of alternating transparent windows and opaque sections, the angular width of all transparent windows and opaque sections being substantially equal; light producing means mounted on one side of said first and second discs positioned to impinge beams of light on both said outer and inner annular arrangements of windows and opaque sections of said discs; a first photodetector means mounted in the encoder body on the opposite side of said first and second discs from said light producing means and positioned to receive light passing through the transparent windows of said outer annular arrangements of windows of said first and second discs; and a second photodetector means mounted in the encoder body on the opposite side of said first and second discs from said light producing means and positioned to receive the light passing through the transparent windows of said inner annular arrangements of windows of said first and second discs, the longitudinal axes of said first and second photodetector means intersecting a radius that is perpendicular to the longitudinal axis of said shaft.
Claim 2
Dependent Claim
263 words
An opto-electronic incremental encoder comprising: a first disc stationarily mounted in an encoder body and a second disc, identical in design to said first disc, rotatably mounted on a shaft, the longitudinal axis of each disc coinciding with the longitudinal axis of said shaft, said first and second discs being positioned adjacent to each other; the first and second discs being provided with an identical outer annular arrangement of alternating transparent windows and opaque sections; the first and second discs being also provided with an identical inner annular arrangement of alternating transparent windows and opaque sections, the angular width of all transparent windows and opaque sections being substantially equal; light producing means mounted on one side of said first and second discs positioned to impinge beams of light on both said outer and inner annular arrangements of windows and opaque sections of said discs; a first photodetector means mounted in the encoder body on the opposite side of said first and second discs from said light producing means and positioned to receive light passing through the transparent windows of said outer annular arrangements of windows of said first and second discs; and a second photodetector means mounted in the encoder body on the opposite side of said first and second discs from said light producing means and positioned to receive the light passing through the transparent windows of said inner annular arrangements of windows of said first and second discs, the longitudinal axes of said first and second photodetector means intersecting a radius that is perpendicular to the longitudinal axis of said shaft.
Claim 3
Dependent Claim
19 words
An opto-electronic incremental encoder according to claim 1 wherein the light producing means is a single light producing means.
Claim 4
Dependent Claim
34 words
An opto-electronic incremental encoder according to claim 1 wherein the longitudinal axes of said first and second photodetectors intersect said radius so as to position said first and second photodetectors adjacent to each other.
Claim 5
Dependent Claim
57 words
An opto-electronic incremental encoder according to claim 1 wherein the windows of the inner annular arrangement of said first and second disc are offset a distance in either direction, equivalent to one fourth of the angular width of the corresponding window in the outer annular arrangement of transparent windows and alternating opaque sections of the respective disc.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-13 | 1979-04-14 | 1979-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-13 | 1983-04-14 | 1983-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-13 | 1987-04-14 | 1987-10-14 | $7700.00 | Window Closed / Lapsed |