| 摘要 |
PROBLEM TO BE SOLVED: To provide an information recording medium capable of stably reproducing small pits for a number of times and having a simple structure. SOLUTION: When a laser beam is emitted toward a base plate having a recording film, the temperature of the base plate rises near the center of the laser beam. Change in the refractive index of this part causes an essential difference in the optical path, making the part a pseudo recessed or projected shape viewed from the incident side of the laser beam. |
