OPTICAL HEAD

PURPOSE:To form an optical head with a short positioning time and information transfer speed by mounting one light source, plural objective lenses and photodetectors to one body. CONSTITUTION:Two sets of components except a semiconductor laser 11 and a collimator lens 12 are assembled in one optical head body 30. Further, actuators 32a, 32b introducing 1/2 wavelength plates 31a, 31b into the optical path of the light beam irradiated from the semiconductor laser 11 and holding off from the optical path optionally are provided. In recording information on an optical disc 17, any of two sets of optical constitution sections shown in suffixes (a, b) is used freely, and in setting the distance between the two sets of the light constituting sections as the same length as nearly half of the recording region width (full track width) in a radial direction used by an optical disc 17, the time when the head is moved in the track direction to record the information is reduced to a half at maximum.