Compact optical pick-up head employing non-diffractive element

摘要

A compact optical pickup head which doesn't utilize a holographic optical element is disclosed. A birefringent prism and a quarter-wave plate are disposed in the optical path of the compact pickup head. The birefringent prism is consisted of two crystals made from a birefringent material, and having their optical axes perpendicular to each other. Therefore, the laser source beam will not be refracted when passing through the birefringent prism or will be refracted to a direction differing from the returning beam), while the returning beam is refracted by the birefringent prism to the photo detector. The power of laser ray is fully utilized to increase the reliability of signal transformation. A higher optical signal can be obtained, and the interference of returning beam to the source beam is also be prevented.