| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize an optical device by reproducing plural optical disks including a digital video disk(DVD) through a common lens. SOLUTION: When an optical device which records or reproduces data on the information recording surface of a DVD by converging light from a light source on the information recording surface through an objective lens and irradiating a photodetecting element with the reflected light from the information recording surface through the objective lens records or reproduces a DVD 4, the whole conditions of 1/|β|<=-0.2.LDVD+13 and -1<=(1/|β|)-0.2.LDVD<=5 are satisfied, where β is lateral magnification and LDVD is a distance (mm) between an object and an image. |
