| 摘要 |
PURPOSE:To obtain good overwrite characteristics without allowing a recorded data to remain unerased by shortening the rise time and fall time of a pulse of higher light intensity or a pulse of shorter pulse duration. CONSTITUTION:A laser diode 2d is driven with a pulse generated by a signal source 1, and hence an emitted laser beam is passed through a polarization beam splitter 5, a galvanomirror 6, a lift prism 7 and an objective lens 8 and converged on a disk surface. Now, a focusing actuator 9, the objective lens 8 and the lift prism 7 are formed as a separate type to be driven independently of an optical head main body, and moreover, wiring between the laser diode 2 and the signal source 1 is shortened by disposing the laser diode 2 close to the signal source 1, so that the rise time and fall time of the pulse can be shortened, thus obtaining good overwrite characteristics. |
