Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – Mechanism control by the control signal
Patent
1986-12-08
1989-01-24
Psitos, Aristotelis M.
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
Mechanism control by the control signal
369109, 369122, 350 371, 250237G, G11B 700
Patent
active
048005479
ABSTRACT:
Apparatus for scanning the information surface of an optical disc record carrier with a radiation beam. Errors in beam focus on such surface are detected by providing two optical gratings in succession in the path of the radiation reflected from the record carrier. The gratings have a constant grating period, which may be equal or in a fixed ratio, the directions of the grating strips of the two gratings intersecting each other at a relatively small angle, thereby forming a Moire interference pattern in the radiation emergent from the two gratings which rotates due to changes in beam focus. This changes the relative amounts of radiation received by an assembly of radiation detecting elements adjacent the second grating, producing a focus error control signal which can be employed for correcting beam focus.
REFERENCES:
patent: 3833769 (1974-09-01), Compaan et al.
patent: 4358200 (1982-11-01), Heamskeik et al.
patent: 4428643 (1984-01-01), Kay
patent: 4532522 (1985-07-01), Tsunoda et al.
Kessels Henricus M. M.
Velzel Christiaan H. F.
Psitos Aristotelis M.
Tamoshunas Algy
U.S. Philips Corporation
LandOfFree
Optical record carrier scanning apparatus with scanning beam foc does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical record carrier scanning apparatus with scanning beam foc, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical record carrier scanning apparatus with scanning beam foc will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-423248