| 摘要 |
PURPOSE:To miniaturize a recording apparatus to a large extent, by forming a recording layer of a photochromic substance having a color forming absorption band in the fundamental wave oscillation wavelength region of a laser element and performing recording and erasure by setting the laser element to a beam source. CONSTITUTION:The entire surface of the recording layer 2 of a recording medium 4 is brought to a color forming state and the recording medium 4 is irradiated with modulated semiconductive laser beam 5 with an oscillation wavelength of 780nm and output of 10mW from the side of a substrate 1 at the time of recording and the irradiated part 7 is selectively heated and erased to record information. Next, the recording medium is irradiated with semiconductive laser beam with an oscillation wavelength of 788nm and output of 0.5mW or less from the side of the substrate 1 and the magnitude of reflected light is detected to perform reading. Next, an area desired to be erased is irradiated with laser beam 6 with second high frequency of 390nm obtained by allowing semiconductive laser beam with oscillation frequency of 780nm to pass through a non-linear optical crystal from the side of the substrate 1 to be changed to the color forming state and erased. |
