EP0441435A1
Expired / Lapsed
EP
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Optical scanning device using a plurality of scanning spots
Assignee: Koninklijke Philips NV
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Filing: 1991-02-04
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Granted: —
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Expires: 2011-02-04
Abstract
Abstract An optical scanning device using a plurality of scanning spots (13, 14, 15, 16) for simultaneously scanning a plurality of information tracks (3, 4, 5, 6) of an optical record carrier (1) is described. Additional servo information such as a tilt signal and an angle error signal of the row of scanning spots with respect to the tracks can be obtained by using a plurality of scanning spots (13, .... 16) for generating a plurality of tracking error signals and/or focus error signals.
Inventors
- 👤 Willem Gerard Opheij
- 👤 Jozef Petrus Henricus Benschop
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 17:20
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/095; G11B7/0956; G11B7/004; G11B7/085; G11B7/0901; G11B7/0903; G11B7/0908; G11B7/0909; G11B7/0948; G11B7/12; G11B7/14; G11B7/002; G11B7/003
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
159 words
A device for optically scanning an information plane in a record carrier, which plane has a track structure, said device comprising a multiple radiation source supplying a plurality of scanning beams, an objective system for focusing each scanning beam to a separate scanning spot on the information plane and a radiation-sensitive detection system for converting radiation from the information plane into electric signals which comprise information about a scanned portion of the information plane, the position of a scanning spot with respect to a scanned track and the degree of focusing of a scanning beam with respect to the information plane, characterized in that each one of a plurality of detectors of the detection system associated with the separate scanning beams is adapted to supply electric signals which comprise information about the position of the associated scanning spot with respect to the track scanned thereby and/or the focusing of the associated scanning beam with respect to the information plane.
Claim 2
Dependent Claim
19 words
A device as claimed in Claim 1, characterized in that the scanning spots are arranged along a first line.
Claim 3
Dependent Claim
20 words
A device as claimed in Claim 1, characterized in that the scanning spots are arranged along a plurality of lines.
Claim 4
Dependent Claim
45 words
A device as claimed in Claim 2, characterized in that the detectors associated with the outer scanning spots of the row are adapted to supply signals which comprise information about the degree of focusing of the associated scanning beams with respect to the information plane.
Claim 5
Dependent Claim
81 words
A device as claimed in Claim 4, characterized in that the radiation source supplies a second set of scanning beams which form a second set of scanning spots on the information plane, which spots are arranged along a second line transverse to the first line of scanning spots, and in that a second set of detectors in the detection system is associated with the second set of scanning beams, a plurality of said detectors being adapted to supply focus error signals.
Claim 6
Dependent Claim
32 words
A device as claimed in Claim 2, 3, 4 or 5, characterized in that all detectors of the detection system are adapted to supply focus error signals for the associated scanning beams.
Claim 7
Dependent Claim
48 words
A device as claimed in Claim 2, 3, 4, 5 or 6, characterized in that an element introducing astigmatism is arranged in the path of the radiation reflected by the record carrier and in that each detector adapted to supply a focus error signal comprises a four-quadrant detector.
Claim 8
Dependent Claim
63 words
A device as claimed in Claim 2, 3, 4, 5 or 6, characterized in that a beam-splitting element for forming two sub-beams from each beam is arranged in the path of the radiation reflected by the record carrier and in that each detector adapted to supply a focus error signal comprises two pairs of detection elements, each pair being associated with one sub-beam.
Claim 9
Dependent Claim
84 words
A device as claimed in Claim 1, 2, 3, 4, 5, 6, 7 or 8, in which a row of scanning spots extends at a small angle to the local track direction, characterized in that the detectors associated with two scanning spots located on both sides of the centre of the row are adapted to supply signals which comprise information about the position of the centre of each one of the two scanning spots with respect to the centre line of the associated track.
Claim 10
Dependent Claim
45 words
A device as claimed in Claim 9, characterized in that all detectors of the detection system are adapted to supply signals which comprise information about the position of the centre of the associated scanning spot with respect to the centre line of the associated track.
Claim 11
Independent Claim
64 words
A device as claimed in Claims 1-10, comprising a collimator lens system arranged between the multiple radiation source and the objective system, characterized in that the lens system comprising the collimator lens system and the objective system is implemented as a double-telecentric system and in that the numerical aperture of the collimator lens system is proportional to the extensiveness of the multiple radiation source.
References Cited (Backward Citations)
EP0019378A1
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EP0092420A1
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EP0313394A2
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