Matsushita Electric Industrial Co., Ltd.

Shinya Shimizu

Toshiya Akagi

Yasuhiro Wada

Eisuke Ishibashi

A ratio of an erase current and a peak current when starting recording is defined as K=iER/iPK (S), and iER11 is set equal to K&#xd7;iPK, and an ideal value iERof an erase current that should be increased according to a temperature change is determined (S). A value obtained by subtracting a current iBT at a bottom level emission intensity when starting recording from a current at an erase level emission intensity after the temperature rises is defined as iER. By measuring this iER, an ideal value iERof the erase current is subtracted from iER, and the resultant current is defined as iBT(S). This iBTis set as an adjustment value of the bottom current, and a value obtained by adding this adjustment value to a bottom current when starting recording is set as a bottom current after change.

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Kadoma, Japan

Shinya Shimizu