The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 28, 1992
Filed:
May. 31, 1989
Yasushi Miyauchi, Hachioji, JP;
Motoyasu Terao, Tokyo, JP;
Hiroshi Yasuoka, Fujisawa, JP;
Tetsuya Nishida, Hachioji, JP;
Keikichi Andoo, Musashino, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The present invention relates to a method of recording on a rewritable recording medium using a laser beam capable of producing at least three discreet levels of power. The three levels of power used for writing to the recording medium is greater than the power required for reading. The present method is unique in that the power level of the laser beam is modulated between high, intermediate, and low levels over a time period so that at least three discreet power levels are radiated to the recording medium during recording. The increment of the radiation energy of the upward pulse from the intermediate level toward the high level is within the range of 0.8 to 1.2 times the decrement of the radiation energy of the downward pulse from the intermediate level to the low level. The present invention provides high density recording capability with minimum non-erasure areas even when the recording medium is formed from a high velocity crystallization (high speed erasure).