Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Reexamination Certificate
2011-03-22
2011-03-22
Haley, Joseph (Department: 2627)
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
C369S047140
Reexamination Certificate
active
07911926
ABSTRACT:
A tracking error signal is generated with stability without being easily affected by a distribution fluctuation of light reflected from an optical disc or by a lens shift.An optical disc drive according to the present invention includes: an objective lens5with an aperture radius r0for converging a light beam emitted from a light source1; a polarizing hologram substrate2for dividing the beam reflected from the optical disc6into branched light beams; a photodetector substrate6, on which at least some of the light beams are incident to generate signals representing the intensities of the light beams; and a shielding mask16for cutting off the beam partially. If xy coordinates are defined on a virtual plane, passing the center of the lens5and intersecting with the optical axis7at right angles, such that an x-axis is parallel to the disc radial direction and a y-axis crosses the x-axis at right angles, the shielding mask16prevents the beam from passing through areas of the virtual plane defined by coordinates (x, y) satisfying |x|>a, |y|>b and a2+b2<r02(where a and b are positive real numbers).
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International Search Report for corresponding Application No. PCT/JP2006/318516 dated Oct. 17, 2006.
Momoo Kazuo
Nishiwaki Seiji
Haley Joseph
Iluyomade Ifedayo
Panasonic Corporation
Renner, Otto, Boiselle & Sklar LLP
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