US3673412A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radiant energy beam scanning method and apparatus
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1970-03-02
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Granted: 1972-06-27
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Expires: 1990-03-02
Abstract
Abstract A radiant energy beam scanning method and apparatus having means for projecting a beam of radiant energy toward and bringing the beam to focus within a scanning plane, scanning means for deflecting the beam laterally to cause scanning motion of the beam along a prescribed scan track within the scanning plane, and servo means for sensing lateral departure of the beam from the scan track, generating tracking error signals related to the direction of such departure, and controlling the scanning means in response to the tracking signals to maintain the beam on the scan track. A recording and playback method and apparatus embodying the scanning apparatus for recording a data track on a record and subsequently playing back the data track.
Inventors
- 👤 Gaylor G Oison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:20
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1362; G02; G02B; G02B27/00; G02B27/40; G11B7/002; G11B7/0033; G11B7/08; G11B7/09
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
213 words
In combination: a radiant energy source; optical means for transmitting a radiant energy beam from said source toward an image plane and bringing said beam to focus in a plane of best focus adjacent said image plane; said optical means comprising focussing means including dithering means for oscillating said best focus plane in a back and forth dither motion along said beam path about a midposition along the path and across said scanning plane whereby the effective area of said scanning field in said scanning plane varies cyclicly and periodically passes through a minimum when said planes coincide, means for sensing said effective field area and generating a focussing error signal representing the direction and amount of displacement of said best focus plane from said scanning plane, and means controlled by said focussing error signal for positioning said midposition of dither motion along said beam path to maintain said planes in coincidence; said dithering means comprising a dithering mirror for reflecting said beam from said source to said scanning plane, and means for oscillating said dithering mirror along said beam path; and said means controlled by said focussing error signal comprising means for positioning the midpoint of oscillation of said dithering mirror along said beam path in response to said focussing error signal.
Claim 2
Dependent Claim
213 words
In combination: a radiant energy source; optical means for transmitting a radiant energy beam from said source toward an image plane and bringing said beam to focus in a plane of best focus adjacent said image plane; said optical means comprising focussing means including dithering means for oscillating said best focus plane in a back and forth dither motion along said beam path about a midposition along the path and across said scanning plane whereby the effective area of said scanning field in said scanning plane varies cyclicly and periodically passes through a minimum when said planes coincide, means for sensing said effective field area and generating a focussing error signal representing the direction and amount of displacement of said best focus plane from said scanning plane, and means controlled by said focussing error signal for positioning said midposition of dither motion along said beam path to maintain said planes in coincidence; said dithering means comprising a dithering mirror for reflecting said beam from said source to said scanning plane, and means for oscillating said dithering mirror along said beam path; and said means controlled by said focussing error signal comprising means for positioning the midpoint of oscillation of said dithering mirror along said beam path in response to said focussing error signal.
Claim 3
Dependent Claim
132 words
The beam scanning method which comprises the steps of: reflecting a beam of radiant energy from a scanning mirror toward and focusing said beam in a scanning plane to form in said plane a scanning energy field; rotating said mirror on its central axis and rocking said mirror on a pivot axis intersecting said rotation axis to cause the beam to scan approximately along a spiral scan track in said plane; sensing lateral departure of said beam from said track and generating an error signal representing the direction of departure of the beam; and regulating the angular position of said mirror about said pivot axis in response to said error signal only to cause said beam to remain generally centered on said track during scanning motion of the beam along said track.
Claim 4
Dependent Claim
132 words
The beam scanning method which comprises the steps of: reflecting a beam of radiant energy from a scanning mirror toward and focusing said beam in a scanning plane to form in said plane a scanning energy field; rotating said mirror on its central axis and rocking said mirror on a pivot axis intersecting said rotation axis to cause the beam to scan approximately along a spiral scan track in said plane; sensing lateral departure of said beam from said track and generating an error signal representing the direction of departure of the beam; and regulating the angular position of said mirror about said pivot axis in response to said error signal only to cause said beam to remain generally centered on said track during scanning motion of the beam along said track.
Claim 5
Dependent Claim
123 words
The method of claim 2 including the additional steps of: oscillating the plane of best focus of said beam in a back and forth dither motion along the path of said beam about a midposition along said path and across said scanning plane whereby the effective area of said scanning field in said scanning plane varies cyclicly and passes through a minimum when said planes coincide; sensing the effective area of said scanning energy field in said scanning plane and generating a focusing error signal representing the direction and amount of displacement of said best focus plane from said scanning plane; and regulating the midposition of dither motion along said beam path in response to said signal to maintain said planes in coincidence.
Claim 6
Dependent Claim
179 words
Radiant energy beam scanning apparatus comprising: a radiant energy source; optical means including a scanning mirror mounted for rotation about its central axis and rocking motion about a pivot axis intersecting said rotation axis for transmitting a radiant energy beam from said source to a scanning plane and bringing said beam to focus in said plane to produce a relatively small area scanning energy field within said plane; scanning means for driving said mirror in rotation on said rotation axis and rocking said mirror on said pivot axis independently of the rotational speed of said mirror on said rotation axis to cause scanning movement of said scanning field along a spiral scan track said plane; and servo means including means defining said spiral scan track in said scanning field, and means for sensing lateral departure of said scanning field from said track, generating tracking signals representing the direction of said departure, and controlling said scanning means in response to said tracking signals only in such a way as to effect scanning movement of said scanning field along said track.
Claim 7
Dependent Claim
179 words
Radiant energy beam scanning apparatus comprising: a radiant energy source; optical means including a scanning mirror mounted for rotation about its central axis and rocking motion about a pivot axis intersecting said rotation axis for transmitting a radiant energy beam from said source to a scanning plane and bringing said beam to focus in said plane to produce a relatively small area scanning energy field within said plane; scanning means for driving said mirror in rotation on said rotation axis and rocking said mirror on said pivot axis independently of the rotational speed of said mirror on said rotation axis to cause scanning movement of said scanning field along a spiral scan track said plane; and servo means including means defining said spiral scan track in said scanning field, and means for sensing lateral departure of said scanning field from said track, generating tracking signals representing the direction of said departure, and controlling said scanning means in response to said tracking signals only in such a way as to effect scanning movement of said scanning field along said track.
Claim 8
Dependent Claim
50 words
Scanning apparatus according to claim 4 wherein: said scanning means comprises a motor for driving said mirror in rotation on said rotation axis and means controlled by said tracking signals for rocking said mirror on said pivot axis independently of the rotational speed of the mirror on said rotation axis.
Claim 9
Dependent Claim
103 words
Scanning apparatus according to claim 4 wherein: said scanning means comprises a rotary mirror support, a motor for driving said mirror support in rotation on said rotation axis, means mounting said mirror on said support for rocking on said pivot axis, means connected between said mirror and support for biassing said mirror to a given position on said pivot axis wherein said scanning field falls approximately on one turn of said scan track, and electrical means connected between said mirror and support and controlled by said tracking signals for angularly positioning said mirror about said pivot axis in response to said tracking signals.
Claim 10
Dependent Claim
138 words
Scanning apparatus according to claim 4 wherein: said scanning field has a plane of best focus along the path of said beam; and said optical means comprises focussing means including dithering means for oscillating said best focus plane in a back and forth dither motion along said beam path about a midposition along the path and across said scanning plane whereby the effective area of said scanning field in said scanning plane varies cyclicly and periodically passes through a minimum when said planes coincide, means for sensing said effective field area and generating a focussing error signal representing the direction and amount of displacement of said best focus plane from said scanning plane, and means controlled by said focussing error signal for positioning said misposition of dither motion along said beam path to maintain said planes in coincidence.
Claim 11
Dependent Claim
68 words
Scanning apparatus according to claim 7 wherein: said dithering means comprising a dithering mirror for reflecting said beam from said source to said scanning plane, and means for oscillating said dithering mirror along said beam path; and said means controlled by said focussing error signal comprises means for positioning the midpoint of oscillation of said dithering mirror along said beam path in response to said focussing error signal.
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) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |