Patent EP0219908A1 successfully refreshed from Google Patents.
EP0219908A1
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Apparatus for optically scanning an information plane
Assignee: Koninklijke Philips NV
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Filing: 1986-10-13
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Granted: —
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Expires: 2006-10-13
Abstract
Abstract The apparatus comprises a radiation source (4), an objective system (6) and, arranged between them, a diffraction grating (9) for separating the beam reflected by the information surface from the beam (5) emitted by the source and for splitting the reflected beam into two sub-beams (5a, 5b). For each sub-beam there is provided an associated detector pair (16,17; 18,19). The grating (9) comprises two sub-gratings (11 and 12) whose grating lines (13, 14) are disposed at opposite angles to the bounding line (26) of the sub-gratings.
Inventors
- 👤 Jacobus Petrus Josephus Heemskerk
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 09:47
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/10; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1353; G02B27/16; G02B27/42; G02B27/4233; G02B27/4238; G02B27/44; G11B7/08; G11B7/09; G11B7/0908; G11B7/0916; G11B7/1381; G11B7/094
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
165 words
An apparatus for optically scanning an information plane, which apparatus comprises a radiation source, an objective system for focussing the radiation beam emitted by the radiation source to form a scanning spot in the information plane, a diffraction grating which is arranged in the path of the beam which has been reflected by the information surface, for splitting said beam into two sub- beams, which grating comprises two sub-gratings and a radiation-sensitive detection system comprising two detector pairs, each detector pair being associated with one sub-beam, characterized in that the sub-gratings have the same grating period and the grating lines of the first sub-grating extend at a first angle and the grating lines of the second sub-grating extend at a second angle, which is equal but opposite to the first angle, to the bounding line of the two sub-gratings and in that for each detector pair the bounding line between the detectors extends transversely of the direction of the grating lines of the associated sub-grating.
Claim 2
Independent Claim
165 words
An apparatus for optically scanning an information plane, which apparatus comprises a radiation source, an objective system for focussing the radiation beam emitted by the radiation source to form a scanning spot in the information plane, a diffraction grating which is arranged in the path of the beam which has been reflected by the information surface, for splitting said beam into two sub- beams, which grating comprises two sub-gratings and a radiation-sensitive detection system comprising two detector pairs, each detector pair being associated with one sub-beam, characterized in that the sub-gratings have the same grating period and the grating lines of the first sub-grating extend at a first angle and the grating lines of the second sub-grating extend at a second angle, which is equal but opposite to the first angle, to the bounding line of the two sub-gratings and in that for each detector pair the bounding line between the detectors extends transversely of the direction of the grating lines of the associated sub-grating.
Claim 3
Dependent Claim
25 words
An apparatus as claimed in Claim 1, in which the detectors are photo diodes, characterized in that the photo-diodes are integrated on a single substrate.
Claim 4
Dependent Claim
31 words
An apparatus as claimed in Claim 2, in which the radiation source is a diode laser, characterized in that the diode laser and the photo-diodes are integrated on a single substrate.
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