| 摘要 |
PURPOSE:To considerably increase information capacity by reading plural kinds of multiple recording information which differ in bit height with different- intensity light beams. CONSTITUTION:Different kinds of bits 15a-15d whose bit height (h) is different and L1-L4 on an optical disk 10 are irradiated with light, and transmitted light PTO, etc., of the disk 10 is photodetected. Those bits vary in transmissivity as a function of the intensity P of projected light and the height (h) and photodetection results when two light beams whose intensity is P1 and P2 are combined to read the respective bits 15a-15d distinctively. For the purpose, plural kinds of bits which differ in height are recorded repeatedly to considerably increase the information capacity. Here, the same result is obtained even when variation in reflection factor is utilized. |
