Optical head with forward and return light beam propagating along a common path

An optical head comprising:

• a light source emitting a forward light beam;
• diffraction gratings for dividing said at least part of the forward light beam into three light beams;
• an objective lens for projecting the three light beams onto an optical record medium as light spots, information being recorded on a record plane of said optical record medium;
• a hologram for receiving return light beams reflected by the optical record medium and dividing at least some of the return light beams into a plurality of light beams;
• a photodetecting means for receiving the plurality of light beams from the hologram to detect the information recorded on the record plane of the optical record medium and further information representing a positional deviation of the light spots with respect to the record plane of the optical record medium;
• and
• a Wollaston polarizing prism provided in a common optical path along which both at least part of the forward light beam and at least one of the return light beams propagate;
• said diffraction gratings and said hologram being formed on an optical element arranged in the common optical path.

An optical head comprising:

• a light source for emitting a forward light beam;
• an objective lens for projecting the forward light beam onto an optical record medium as a light spot, information being recorded on a record plane of said optical record medium;
• a photodetecting means for receiving a return light beam reflected by the optical record medium to detect the information recorded on the record plane of the optical record medium and further information representing a positional deviation of the light spot with respect to the record plane of the optical record medium;
• a Wollaston polarizing prism provided in a common optical path along which both at least part of the forward light beam and at least part of the return light beam propagate;
• and
• dividing means, disposed in the common optical path between the Wollaston polarizing prism and the light source, for dividing at least one of the forward light beam and the return light beam so that the return light beam forms multiple light spots on the photodetecting means, the photodetecting means detecting the information and the further information by detecting the multiple light spots.