| 摘要 |
PROBLEM TO BE SOLVED: To make possible forming a high recording density disk by eliminatting wave front aberration affected from various optical elements with a pin hole. SOLUTION: A numerical aperture and the focal distance of an objective lens 48 are prescribed values. The lens 36a and the lens 36b whose focal distances are equal and the prescribed value to constitute a relay lens temporarily converging recording. A pin hole 38 is arranged on the position optically conjugate with a photosensitive material surface of a master disk 50 for an optical disk, that is, on a converged surface between the relay lenses 36a, 36b. The size of the pin hole 38 is decided by multiplying a half width of a recording spot by a magnification of an optical system consisting of the lenses 40, 36a, 36b. By that recording light passes through the pin hole 38, the wave front aberration affected by many optical elements is eliminated. |
