| 摘要 |
PURPOSE:To enable recording density on a recording medium to be improved by using an apparent high-output short-wavelength laser. CONSTITUTION:Two semiconductor lasers 1 and 2 with a different wavelength and an optical lens (collimator lenses 3 and 4 and an objective lens 8) for condensing two optical beams obtained from two semiconductor lasers 1 and 2 at one point on a recording medium 11 are provided and then either one of two semiconductor lasers 1 and 2 is allowed to emit light or both are allowed to emit light simultaneously for recording, reproduction, and erasure. |
