Planar integrated micro-optical pickup head including two planar cylindrical collimators

A planar integrated micro-optical pickup head used to perform reading and writing operations on a disk, the pickup head comprising:

• an optical assembly comprised of a lower substrate and an upper substrate, wherein the lower substrate supports a beam splitter, a first planar collimator, a first folding mirror and a fourth folding mirror, the upper substrate supports a second folding mirror, a second planar collimator, a third folding mirror, and a photo-detector, the above elements supported on the lower and upper substrates are fabricated via semiconductor planar fabrication processes;
• a laser source attached on the lower substrate at a first appropriate location to provide a laser beam of short wavelength;
• and
• an objective lens mounted on the lower substrate at a second appropriate location;
• wherein the lower substrate and the upper substrate are aligned and attached with each other to form the planar integrated micro-optical pickup head;
• the laser beam emitted from the laser source travels through the optical assembly to be collimated two times into a circular laser beam, the circular laser beam passing through the objective lens to be focused and projected onto the disk;
• the laser beam after reflection from the disk is projected into the photo-detector to be converted into a data signal, a focus signal, and a track course error signal.