US3567855A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scanning apparatus with automatic beam centering
Assignee: Robert Bosch GmbH
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Filing: 1969-03-03
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Granted: 1971-03-02
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Expires: 1989-03-03
Abstract
Abstract An elongated focal light spot whose intensity gradually varies along its length, crosses a track of a record carrier having light permeable recordings and scans the same. When the record carrier is undesirably displaced, signals whose intensity varies pass through the light permeable recordings and are received by a photocell which produces varying output signals controlling regulating means by which the focal light spot is again centered on the track.
Inventors
- 👤 Hansjoachim Hamisch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 11:01
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1381; G11B7/08; G11B7/09; G11B7/0901; G11B7/1398; H; H04; H04N; H04N5/00; H04N5/76
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
282 words
Regulated scanning apparatus comprising, in combination, a source of light for producing a beam, lens means in said beam for forming an elongated vocal spot; means in said beam for varying the intensity of said focal spot along the length thereof so that said intensity increases from one end to the other of said spot; a record carrier having light-permeable recordings disposed along track means, the width of said track means beiNg less than the length of said focal spot; means for positioning said lens means and said record carrier relative to each other so that said elongated focal spot is located on said record carrier, crosses said track means, is substantially centered on the same, and has ends transversely projecting from the same; means for moving said lens means and said record carrier relative to each other so that light from said focal spot passes successively through light permeable recordings of said track means; photocell means disposed for receiving light passing from said focal spot through said light permeable recordings, and producing upon relative transverse displacement between said track means and said focal spot, signals which vary due to the different intensities at said ends of said focal spot; regulating means located in said beam for adjusting in a transverse direction the relative position between said focal spot and said track means; and circuit means receiving said varying signals from said photocell and being connected with said regulating means for controlling the same in accordance with said varying signals so that the same center said focal spot on said track means when a variation of said varying signals indicates an undesirable relative displacement between said focal spot and said track means.
Claim 2
Dependent Claim
282 words
Regulated scanning apparatus comprising, in combination, a source of light for producing a beam, lens means in said beam for forming an elongated vocal spot; means in said beam for varying the intensity of said focal spot along the length thereof so that said intensity increases from one end to the other of said spot; a record carrier having light-permeable recordings disposed along track means, the width of said track means beiNg less than the length of said focal spot; means for positioning said lens means and said record carrier relative to each other so that said elongated focal spot is located on said record carrier, crosses said track means, is substantially centered on the same, and has ends transversely projecting from the same; means for moving said lens means and said record carrier relative to each other so that light from said focal spot passes successively through light permeable recordings of said track means; photocell means disposed for receiving light passing from said focal spot through said light permeable recordings, and producing upon relative transverse displacement between said track means and said focal spot, signals which vary due to the different intensities at said ends of said focal spot; regulating means located in said beam for adjusting in a transverse direction the relative position between said focal spot and said track means; and circuit means receiving said varying signals from said photocell and being connected with said regulating means for controlling the same in accordance with said varying signals so that the same center said focal spot on said track means when a variation of said varying signals indicates an undesirable relative displacement between said focal spot and said track means.
Claim 3
Dependent Claim
51 words
Apparatus as claimed in claim 1 wherein said circuit means include means for forming of varying signals occurring within a predetermined time period an average control signal varying when said signals vary, said regulating means being controlled by said average control signal to center said focal spot on said track means.
Claim 4
Dependent Claim
43 words
Apparatus as claimed in claim 2 wherein said means for forming an average control signal include a resistor-capacitor circuit having a predetermined time constant substantially greater than the scanning time of a recording; and a diode between said photocell and said resistor-capacitor circuit.
Claim 5
Dependent Claim
23 words
Apparatus as claimed in claim 1 wherein said lens means include a cylinder lens and a focusing lens forming an astigmatic focusing system.
Claim 6
Dependent Claim
35 words
Apparatus as claimed in claim 1 wherein said means for varying the intensity of said focal spot varies said intensity between said ends of said focal spot in accordance with a substantially constant intensity gradient.
Claim 7
Dependent Claim
17 words
Apparatus as claimed in claim 5 wherein said means for varying the intensity includes a gray wedge.
Claim 8
Dependent Claim
73 words
Apparatus as claimed in claim 1 comprising a diaphragm located in said beam and having a slot extending across said beam in one direction and being narrow in a direction perpendicular to said one direction, said perpendicular direction being parallel to the longitudinal direction of said focal spot so that the length of said focal spot is reduced and undesired outer portions of said beam do not participate in forming said focal spot.
Claim 9
Dependent Claim
68 words
Apparatus as claimed in claim 7 wherein said means for varying the intensity of said focal spot includes a gray wedge covering said slot and constructed to vary the intensity of the portion of the beam passing through said slot so that the intensity of said focal spot increases from one end to the other end of said focal spot in accordance with a substantially constant intensity gradient.
Claim 10
Dependent Claim
40 words
Apparatus as claimed in claim 1 wherein said regulating means include movable deflecting mirror means located in said beam, and electrical control means connected with said circuit means for displacing said deflecting mirror means in accordance with said varying signals.
Claim 11
Dependent Claim
50 words
Apparatus as claimed in claim 9 wherein said electrical control means include a pair of piezoceramic members having connectors connected with said circuit means for receiving signals from the same, said piezoceramic members being connected with said deflecting mirror means for displacing the same so that said beam is deflected.
Claim 12
Dependent Claim
43 words
Apparatus as claimed in claim 9 wherein said lens means include a cylinder lens, and a focusing lends disposed closer to said recorD carrier than said cylinder lens; and wherein said regulating means is located between said cylinder lens and said focusing lens.
Claim 13
Dependent Claim
113 words
Apparatus as claimed in claim 1 comprising means for producing a control voltage proportionate to intensity variations of said source of light; wherein said circuit means forms of said varying signals a regulating voltage also depending on intensity variations of said source of light; a differential amplifier receiving said control voltage and said regulating voltage and producing a differential voltage supplied to said regulating means for controlling the same so that said regulating means is not influenced by variations of said regulating voltage caused by intensity variations of said source of light and responds only to variations of said regulating voltage caused by relative displacement between said focal spot and said track means.
Claim 14
Dependent Claim
70 words
Apparatus as claimed in claim 12 wherein said means for producing a control voltage include a partly transparent mirror located in said beam and projecting an auxiliary beam from the same, another photocell receiving said auxiliary beam and producing an output voltage; and a voltage divider between said other photocell and said differential amplifier for receiving said output voltage and for supplying an adjusted control voltage to said differential amplifier.
Claim 15
Dependent Claim
213 words
Apparatus as claimed in claim 1 wherein said circuit means include means for forming of varying signals occurring within a predetermined time period an average control signal varying when said signals vary, said regulating means being controlled by said average control signal to center said focal spot on said track means; wherein said lens means include a cylinder lens and a focusing lens forming an astigmatic focusing system; wherein said means for varying the intensity of said focal spot varies said intensity between said ends of said focal spot in accordance with a substantially constant intensity gradient, and includes a gray wedge; comprising a diaphragm located in said beam and having a slot extending across said beam in one direction and being narrow in a direction perpendicular to said one direction, said perpendicular direction being parallel to the longitudinal direction of said focal spot so that the length of said focal spot is reduced and undesired outer portion of said beam do not participate in forming said focal spot, said slot being covered by said gray wedge; and wherein said regulating means include movable deflecting mirror means located in said beam, and electric control means connected with said circuit means for displacing said mirror means in accordance with said varying average control signal.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |