Pyong-yong Seong

Lens device comprising light blocking means and an optical pickup apparatus using the lens device

Optical recording and reproducing apparatus, tilt adjusting method appropriate therefor, and recording control method

Optical pickup device with light spot size adjustment for different density disks

Optical pickup and optical recording and/or reproducing apparatus adopting the same

Optical pickup apparatus and optimal light spot focusing method

Optical pickup using objective lens compatible with a plurality of optical disks

Optical pickup, optical recording and/or reproducing apparatus including the same, and method for realizing compatible tracking

Optical recording and pickup head for digital versatile disc compatible with read-writable compact disc by adopting flat plate lens having staircase type diffraction grating structure

Optical pickup for correcting an astigmatic difference of light

Optical pickup assembly with adjustable inclination