Optical disk device

Abstract

Abstract PURPOSE:To shorten an access time with an optical disk by dividing a recording area into plural pieces to change the recording bit rate for each divided recording area, therefore increasing the recording capacity together with the revolving speed kept constant. CONSTITUTION:The recording surface of a photomagnetic disk plate 1 is divided into two recording areas, i.e., an inner area 2 that occupies (2/4)R-(3/4)R of the plate 1 having a radium R and an outer area 3 that occupies (3/4)R-R of the plate 1 respectively. Then the recording bit rate is set at 2:3, for example, between both areas 2 and 3. The signal A supplied from an input terminal IN is divided into signals B and C by a distributing circuit 10. These signals B and C are supplied to optical heads 5 and 6 via a fixed optical system 8 and recorded in the area 2 and 3 respectively. Thus the recording area is used effectively with increase of the recording capacity. Then the shift distances of both heads 5 and 6 are reduced down to 1/2 for reduction of the access time.

Inventors

• 👤 Shozo Nakagawa
• 👤 中川　省三
• 👤 Koichi Okabe
• 👤 公一 岡部
• 👤 Shunichi Onishi
• 👤 俊一 大西

Bibliographic Details