US3862428A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Holographic spatial encoder
Assignee: RTX Corp
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Filing: 1973-10-11
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Granted: 1975-01-21
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Expires: 1993-10-11
Abstract
Abstract A hologram in the form of a hologram disk is constructed from an optical encoder disk containing binary information. The hologram disk may be mounted on a shaft for rotation therewith as in conventional encoders. The hologram disk is illuminated by a reconstruction beam such as a laser beam to form an image of the original optical encoder disk. An array of photodetectors positioned adjacent the reconstructed image reads out the binary information contained in the encoder disk.
Inventors
- 👤 James P Waters
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:29
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/347; G01D5/3473; G02; G02B; G02B5/00; G02B5/32; H; H03; H03M; H03M1/00; H03M1/12; H03M1/22; H03M1/24; H03M1/26; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
157 words
A method for producing discrete digital output data indicative of the position of rotatable shaft comprising The steps of producing a first optical encoder disk having binary information coded thereon in the form of opaque and transparent portions, photoreducing said optical encoder disk to produce a second optical encoder disk of reduced diameter from said first optical encoder disk, forming on an annular photographic plate a holographic image of said second optical encoder disk, said photographic plate being of reduced diameter from said first and second optical encoder disks, developing said photographic plate, mounting said photographic plate on a rotatable shaft for rotation therewith, illuminating said photographic plate with a coherent optical beam to form a reconstructed real image of the coded binary information contained on said first optical encoder disk, reflecting from an elliptical mirror a selected radial portion of said real image, and detecting the coded information contained in the reflected portion of said image.
Claim 2
Independent Claim
157 words
A method for producing discrete digital output data indicative of the position of rotatable shaft comprising The steps of producing a first optical encoder disk having binary information coded thereon in the form of opaque and transparent portions, photoreducing said optical encoder disk to produce a second optical encoder disk of reduced diameter from said first optical encoder disk, forming on an annular photographic plate a holographic image of said second optical encoder disk, said photographic plate being of reduced diameter from said first and second optical encoder disks, developing said photographic plate, mounting said photographic plate on a rotatable shaft for rotation therewith, illuminating said photographic plate with a coherent optical beam to form a reconstructed real image of the coded binary information contained on said first optical encoder disk, reflecting from an elliptical mirror a selected radial portion of said real image, and detecting the coded information contained in the reflected portion of said image.
References Cited (Backward Citations)
US3731373A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-20 | 1978-07-22 | 1979-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-20 | 1982-07-22 | 1983-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-20 | 1986-07-22 | 1987-01-21 | $7700.00 | Window Closed / Lapsed |