An optical head device adapted to be optically coupled to an optical disk includes a light-source laser and an objective lens optically coupled thereto. This lens receives an output light of the light source, and causes it to be projected onto the optical disk to form a focused spot thereon. Photodetectors...http://www.google.ca/patents/US6154433?utm_source=gb-gplus-sharePatent US6154433 - Light beam shaping device to change an anisotropic beam to an isotropic beam for reducing the size of an optical head
