| 摘要 |
PURPOSE:To record data with high density by reproducing the data by detecting the position information of 1st-order diffracted light moving relatively against 0th-order diffracted light corresponding to a pit interval. CONSTITUTION:A laser beam irradiating an optical disk 22 is diffracted by a pit on the disk, and is reflected, and is made incident on an objective lens 20. In the inside of the pupil 34 of the objective lens 20, an image in which the image 38 of positive 1st-order diffracted light and the image 40 of negative 1st-order diffracted light are arranged in a direction of X via the image 36 of the 0th-order diffracted light can be obtained, and the interval between the images 38 and 40 of the positive 1st-order diffracted light can be increased as the pit interval is decreased. Original data recorded on the optical disk 22 is reproduced by detecting the interval between the images 38 and 40 of the + or -1st-order diffracted light by an optical detector such as a photodiode array 26, etc. In such a manner, it is possible to easily detect the pit interval, and to reproduce the data recorded with high density. |
