Optical disk for use in optical memory devices

A method for the production of an optical memory master plate for creating an optical disk having a plurality of substantially parallel and radially extending guide tracks and information pits formed therebetween, using a disk plate having a first surface and a second surface, the steps comprising:

• forming only a single photoresist film on the first surface of said disk plate;
• exposing said single photoresist film to first and second columns of laser beams;
• developing said single photoresist film resulting in a patterned photoresist film;
• forming a metal film on the first surface of said disk plate with the patterned single photoresist film, and
• wherein said exposing step further comprising,
• disposing said first and second columns of laser beams in a radial direction along the first surface of said disk plate illuminating said photoresist film through an object lens by radially shifting said laser beams in such a way that a portion of one of said laser beams is superimposed upon an adjacent previously exposed area resulting in an exposed area that is wider than the previously exposed area formed before said laser beams are shifted, said widely exposed area defining a plurality of guide groove latent images along a fixed radial path, and
• shifting a selected one of said first and second columns of laser beams on said fixed radial path and deflecting said other column away from said disk plate thereby illuminating said photoresist film in defined areas using said selected column for forming information pits between said widened guide grooves and along said fixed path, so that a disk plate is formed with a first surface and a second surface, with grooves and pits of different depths with the bottom of the pits and grooves being equidistant spaced from said second surface,
• wherein said exposing step further comprises:
• adjusting the relative position between said first and second beams said fixed distance for forming a land area between said plurality of guide grooves so that said first surface has a first top portion containing said pits and a second top portion containing said grooves, and said first top portion is spaced a greater distance from said second surface than said second top portion.