US4665310A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for optically scanning an information plane wherein a diffraction grating splits the beam into two sub-beams
Assignee: US Philips Corp
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Filing: 1985-12-26
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Granted: 1987-05-12
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Expires: 2005-12-26
Abstract
Abstract An apparatus is described for optically scanning an information surface (2). 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 P. J. Heemskerk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:41
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
163 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, 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 extent at a first angle and the grating lines of the second sub-grating extent 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
163 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, 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 extent at a first angle and the grating lines of the second sub-grating extent 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.
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) | 1990-05-11 | 1990-11-10 | 1991-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-11 | 1994-11-10 | 1995-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-11 | 1998-11-10 | 1999-05-12 | $7700.00 | Window Closed / Lapsed |