| 摘要 |
PURPOSE:To eliminate the need for a beam shaping prism, to miniaturize a device and, simultaneously, to shorten the access time to a track by adjusting the intensity distribution of a laser beam outputted from a semiconductor laser so as to be uniformed through the use of an optical filter. CONSTITUTION:For the laser beam outputted from a semiconductor laser 1, the intensity distribution is not uniform, and it has a peak. However, for the laser beam emitted from the semiconductor laser 1, by passing through an optical filter 2 having a transmitivity distribution to be aproximately inhour to the intensity distribution, the peak part is made flat, the intensity distribution is adjusted to be uniformed, and thereby, at the time of executing a convergence on a recording medium 5 by an objective 4, an optimum spot shape can be obtained. Since the beam shaping prism is not used, the optical head main body can be miniaturized and reduced in weight, and the access time to the objective track on the recording medium 5 can be shortened. |
