| 摘要 |
PURPOSE:To improve groove shapes at the time of preformatting the optical master disk by forming grooves wider than pits together with the pits on the photoresist film of the optical master disk. CONSTITUTION:A recording beam is passed through 1st and 2nd acoustooptical elements 1, 2. The arrays of the pits are formed when the beam is modulated by the 1st acoustooptical element 1 and is passed through the 2nd acoustooptical element 2. The beam past the 1st acoustooptical element is made incident on the 2nd acoustooptical element and the photoresist film is irradiated with the transmitted light, zero order light and 1st order light of the recording beam generated by subjecting the 2nd acoustooptical element 2 to on/off driving at the frequency period larger than 5MHz by parting the beams while overlapping the beams in the circumferential and diametral directions of the beam, by which the grooves broader than the beam spot are formed. |
