Patent ID: 6259668
Filing Date: 2001-07-10
Classification: G11B

Abstract:
A recording and/or reproducing apparatus compatible with disks having different thicknesses, comprising:an optical pickup device comprisinga light source,an objective lens, facing of the disks which is placed in the optical device, having a light passing region divided into central, intermediate and periphery regions respectively corresponding to a near axis area, an intermediate axis area and a far axis area of incident light, wherein curvatures of the central and periphery regions are optimized for the one disk if the one disk has a first thickness and a curvature of the intermediate region is optimized for the one disk if the one disk has a second thickness greater than the first thickness,a photo detector for detecting light reflected from the one disk, anda beam splitter, disposed between said objective lens and said light source, for transmitting/reflecting light from said light source toward said objective lens and for reflecting/transmitting light reflected from the one disk toward said photo detector; anda processing unit to process an information signal to control the incident light generated by the light source, and to process the detected light from the photo detector;wherein a first working distance between the objective lens and a near surface of the one disk if the one disk has the first thickness is greater than a second working distance between the objective lens and a near surface of the one disk if the one disk has the second thickness.