Patent ID: 7643049

Claim:
An apparatus for manufacturing a production plate used when manufacturing recording media by exposing a material layer formed on a substrate composing the production plate to a laser beam in accordance with a recording pattern to produce altered parts and developing the material layer to remove either the altered parts or the non-altered parts of the material layer, the apparatus comprising: holding means for holding the substrate composing the production plate, wherein the material layer, which has a predetermined reflectivity for the laser beam to which the substrate is exposed, is formed on at least one principal surface of the production plate, and wherein the material layer is an etching mask for the substrate; a laser source producing a blue-violet laser beam; modulating means for modulating the blue-violet laser beam produced by the laser source in accordance with the recording pattern and also modulating the blue-violet laser beam; an optical system that includes a condensing lens system for focusing the blue-violet laser beam on the material layer; moving means for moving an incident position of the blue-violet laser beam on the material layer; and focus adjusting means for adjusting focus by detecting return light that is the blue-violet laser beam reflected back off the material layer, wherein the modulating means is composed of a high-speed modulator and a low speed modulator, wherein the low-speed modulator modulates the blue-violet laser beam in accordance with the recording pattern, and wherein the low speed modulator uses an electro-optic effect.