Optical pickup device

Abstract

Abstract PURPOSE:To eliminate influences of the aberration of a lens in tracking and focusing and the coma aberration due to the protective layer of a disk, by moving parallel light in a lens barrel consisting of a polarizing prism, a lambda/4 plate and a stop-down lens. CONSTITUTION:Parallel light generated by a semiconductor laser and a compound lens 2 is stopped down on the recording surface of a disk 6 through a polarizing prism 3, a lambda/4 plate 4, and a stop-down lens 5, and the light reflected on the recording surface passed through the lens 5 and lambda/4 plate 6 and changed in direction by 90 deg. through the polarizing prism 3 to reach a concave mirror 8 via a lambda/4 plate 7, so that it reaches a photodetecting element 9 by being reflected and focused. Even when a lens barrel 10 is moved up and down, right and left, and back and forth in parallel, the optical path in the lens barrel does not shift at all including the state of a wave surface, and out of focus, a shift in tracking, the aberration of the stop-down lens, etc., due to the oscillation of the lens barrel 10 are avoided.

Inventors

• 👤 Keiichi Yoshizumi

Bibliographic Details