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US3904835A
Expired / Lapsed
US
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Reconstruction method of an optically recorded signal
Assignee: Canon Inc
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Filing: 1972-12-04
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Granted: 1975-09-09
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Expires: 1992-12-04
Abstract
Abstract An arrangement is described for reading out in electrical form a signal manifested as light intensity variations of a carrier frequency along a recording film. The film is illuminated with monochromatic light to diffract the light into a plurality of different order waves. A pair of such different order waves are superposed by interference pattern forming means to generate, at an image plane, a differential fringe pattern containing the spatial intensity variations of the desired signal but not of the carrier. During a longitudinal advance of the film, a photoelectric detector disposed at the image plane detects the intensity variations of the interference fringe pattern to reproduce the desired signal.
Inventors
- 👤 Kazuya Matsumoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:35
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/002; G11B7/0033; G03; G03H; G03H1/00; G03H1/22; G11B7/003; G11B9/00
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
144 words
A method of reproducing time variations of a control signal recorded on a recording member in the form of corresponding spaced diffraction grid variations along a predetermined scanning direction, which comprises the steps of: illuminating a part of said recording member with a monochromatic coherent light beam to propagate a plurality of diffracted waves of different order from the recording member; advancing the recording member in said scanning direction relative to the monochromatic coherent light beam; directing a diffracted wave front, which is selected from said plurality of different order diffracted waves, onto a photoelectric surface for making an interference fringe pattern whose spaced fringe may be rougher than said spaced diffraction grid; and detecting the variations in intensity of the interference fringe pattern at the photo-electronic surface while the recording member advances in order to reproduce the time variations of the control signal.
Claim 2
Independent Claim
144 words
A method of reproducing time variations of a control signal recorded on a recording member in the form of corresponding spaced diffraction grid variations along a predetermined scanning direction, which comprises the steps of: illuminating a part of said recording member with a monochromatic coherent light beam to propagate a plurality of diffracted waves of different order from the recording member; advancing the recording member in said scanning direction relative to the monochromatic coherent light beam; directing a diffracted wave front, which is selected from said plurality of different order diffracted waves, onto a photoelectric surface for making an interference fringe pattern whose spaced fringe may be rougher than said spaced diffraction grid; and detecting the variations in intensity of the interference fringe pattern at the photo-electronic surface while the recording member advances in order to reproduce the time variations of the control signal.
Claim 3
Dependent Claim
16 words
A method as defined in claim 1, in which the recording member is an elongated film.
Claim 4
Dependent Claim
39 words
A method as defined in claim 1, in which the illuminating step includes projecting a pair of monochromatic light beams against the advancing film at substantially equal angles of incidence relative to a direction normal to the film axis.
Claim 5
Dependent Claim
29 words
A method as defined in claim 1, further comprising the step of selecting the zero order diffracted wave and a first order one of the diffracted waves for superposition.
Claim 6
Dependent Claim
24 words
A method as defined in claim 1, further comprising the step of selecting a pair of the diffracted waves of conjugate orders for superposition.
Claim 7
Independent Claim
146 words
A method of reproducing time variations of a control signal recorded on a recording member in the form of corresponding spaced diffraction grid variations along a predetermined scanning direction, which comprises the steps of: illuminating a part of said recording member with a monochromatic coherent light beam to propagate a plurality of diffracted waves of different order from the recording member; advancing the recording member in said scanning direction relative to the monochromatic coherent light beam; directing a pair of diffracted wave fronts which are selected from said plurality of different order diffracted waves onto a photo-electronic surface for making an interference fringe pattern whose spaced fringe may be rougher than said spaced diffraction grid; and detecting the variations in intensity of the interference fringe pattern at the photo-electronic surface while the recording member advances in order to reproduce the time variations of the control signal.
Claim 8
Independent Claim
146 words
A method of reproducing time variations of a control signal recorded on a recording member in the form of corresponding spaced diffraction grid variations along a predetermined scanning direction, which comprises the steps of: illuminating a part of said recording member with a monochromatic coherent light beam to propagate a plurality of diffracted waves of different order from the recording member; advancing the recording member in said scanning direction relative to the monochromatic coherent light beam; directing a pair of diffracted wave fronts which are selected from said plurality of different order diffracted waves onto a photo-electronic surface for making an interference fringe pattern whose spaced fringe may be rougher than said spaced diffraction grid; and detecting the variations in intensity of the interference fringe pattern at the photo-electronic surface while the recording member advances in order to reproduce the time variations of the control signal.
Claim 9
Dependent Claim
167 words
Apparatus for optically recording an electrical control signal on an elongated film and for reading out the resulting optical record, which comprises; means for advancing the film longitudinally, means for directing a monochromatic light beam against the film in a direction normal to the film axis to propagate a plurality of different order diffracted waves from the film; optical modulating means responsive to electrical variations applied to a control input thereof for varying the beam along The axis of the film in proportion to such variations; means for applying the control signal to the control input of the optical modulating means; pattern forming means disposed in the paths of certain of the diffracted waves for superposing at least two selected orders of said waves and for generating an interference fringe pattern of the selected orders on a predetermined surface; and photosensitive detecting means disposed at the predetermined surface for sensing variations in intensity of the fringe pattern while the film advances to generate a time-varying output signal.
Claim 10
Dependent Claim
167 words
Apparatus for optically recording an electrical control signal on an elongated film and for reading out the resulting optical record, which comprises; means for advancing the film longitudinally, means for directing a monochromatic light beam against the film in a direction normal to the film axis to propagate a plurality of different order diffracted waves from the film; optical modulating means responsive to electrical variations applied to a control input thereof for varying the beam along The axis of the film in proportion to such variations; means for applying the control signal to the control input of the optical modulating means; pattern forming means disposed in the paths of certain of the diffracted waves for superposing at least two selected orders of said waves and for generating an interference fringe pattern of the selected orders on a predetermined surface; and photosensitive detecting means disposed at the predetermined surface for sensing variations in intensity of the fringe pattern while the film advances to generate a time-varying output signal.
Claim 11
Dependent Claim
121 words
Apparatus for reproducing time variations of a control signal recorded on an elongated film in the form of correspondingly spaced intensity variations along the film, which comprises; means for advancing the film longitudinally; means for illuminating the advancing film with monochromatic light to propagate a plurality of diffracted waves of different orders from the film; pattern forming means disposed in the paths of certain of the diffracted waves for superposing at least two selected orders of said waves and for generating an interference fringe pattern of the selected orders on a predetermined surface; and photosensitive detecting means disposed at the predetermined surface for sensing variations in intensity of the fringe pattern while the film advances to generate a time-varying output signal.
Claim 12
Dependent Claim
121 words
Apparatus for reproducing time variations of a control signal recorded on an elongated film in the form of correspondingly spaced intensity variations along the film, which comprises; means for advancing the film longitudinally; means for illuminating the advancing film with monochromatic light to propagate a plurality of diffracted waves of different orders from the film; pattern forming means disposed in the paths of certain of the diffracted waves for superposing at least two selected orders of said waves and for generating an interference fringe pattern of the selected orders on a predetermined surface; and photosensitive detecting means disposed at the predetermined surface for sensing variations in intensity of the fringe pattern while the film advances to generate a time-varying output signal.
Claim 13
Dependent Claim
56 words
Apparatus as defined in claim 8, in which the illuminating means comprises means for directing a pair of monochromatic light beams toward the film at different angles with respect to the normal to the film axis, said angles being chosen so that a pair of different orders of the diffracted waves propagate parallel to the normal.
Claim 14
Dependent Claim
62 words
Apparatus as defined in claim 8, in which the illuminating means comprises means for directing a monochromatic light beam toward the film in a direction substantially normal to the film axis, and in which the pattern forming means comprises means for redirecting at least one of the diffracted wave orders so that a pair of such orders propagate parallel to the normal.
Claim 15
Dependent Claim
28 words
Apparatus as defined in claim 8, in which the pattern forming means comprises lens means and pin hole means for selecting the desired orders on the predetermined surface.
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) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |