| 摘要 |
PURPOSE:To considerably increase information capacity by reading many kinds of multiple recording information which differ in bit height with different- wavelength light beams. CONSTITUTION:Pieces of information of different bits 16 whose height (h) is different and h1-h3 on an optical disk 10 are irradiated with light with wavelength lambda1 orlambda2, etc., which is reflected by a half-mirror 13, and its reflected light is passed through a mirror 13 and photodetected by a photodetector 18. The intensity of this photodetected light varies as a function of the wavelength lambdaand height (h) by the interference between reflected light beams from a base surface 10a and the surface of a bit 16. Therefore, plural kinds of multiple recording which differs in bit height are read out with the light beams with the different wavelengths lambda1 and lambda2 and distinguished according to combinations of read results; and those many kinds of bit information are recorded repeatedly to considerably increase the information capacity. |
