Reading optical disks having substrates with diverse axial thick

Details Reading optical disks having substrates with diverse axial thick Reading optical disks having substrates with diverse axial thick

1995-06-07

1997-04-15

Ben, Loha

Dynamic information storage or retrieval

Specific detail of information handling portion of system

Radiation beam modification of or by storage medium

369116, 369 4425, 369 54, 369 94, G11B 700

Patent

active

056217170

ABSTRACT:
An optical disk player reads either thin-substrate disks or thick-substrate disks. The disk players optical system is designed for reading the thin-substrate optical disks and has an effective numerical aperture. Thick-substrate optical disks having a thicker substrate than the thin-substrate optical disk result in the laser beam reading such thick-substrate optical disks having spherical aberration sufficient to prevent reliable data detection. When thick-substrate optical disks are being read, the read portion of the optical system is automatically changed to accommodate the undesired spherical aberration. The thick-substrate disk reflected laser beam is subjected to annular filtering that reduces spherical aberration sufficiently for enabling data and servo signal detection. Annular filtering is provided in an optical read path by an effective opaque or translucent disk centrally located in a pupil of the laser beam optical filter disposed in the read portion. An apertured plate having an aperture comparable to a known diffraction limited spot size is disposed between the laser beam filter and photo detectors. The apertured plate is disposed in the focal region of a lens in the optical read path.

REFERENCES:
patent: 4460990 (1984-07-01), Opheij
patent: 4914725 (1990-04-01), Belser et al.
patent: 5070495 (1991-12-01), Bletscher, Jr. et al.
patent: 5072437 (1991-12-01), Chikuma
patent: 5202875 (1993-04-01), Rosen et al.
patent: 5268893 (1993-12-01), Call et al.
patent: 5309461 (1994-05-01), Call et al.
patent: 5349592 (1994-09-01), Ando
patent: 5396476 (1995-03-01), Asthana
patent: 5434840 (1995-07-01), Ezuka et al.
patent: 5446565 (1995-08-01), Komma et al.
Born et al Principles of Optics, Permagon Press, 1975, pp. 416-417 and 440-441.
Strand et al., "Aberration Limits for Annular Gaussian Beams for Optical Storage", Applied Optics, vol. 33, No. 16, 1 Jun. 1994, pp. 3533-3539.

Affiliated with

Also associated with

Rating

Reading optical disks having substrates with diverse axial thick does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Reading optical disks having substrates with diverse axial thick, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reading optical disks having substrates with diverse axial thick will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-366914