ORIGINAL DISK ALIGNER, TRACK PITCH EVALUATING DEVICE THEREFOR, TRACK PITCH EVALUATING METHOD, AND ORIGINAL DISK MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To correctly measure and evaluate a pitch between tracks in a spiral shape, that is, a track pitch in an optical disk alignment. SOLUTION: Difference between a counted value CNT[m, N-1] of a counter indicating a shift position of an original optical disk before one track ((N-1) track) and a counted value CNT[m, N] of a counter indicating a shift position of an original optical disk of the present track ((N) track) is calculated with timing of the prescribed rotation position signal generated by a rotary encoder, that is, the same rotation angle position. Thereby, track pitch between adjacent tracks in a spiral shape formed on the original optical disk is evaluated correctly as track pitch deviation. COPYRIGHT: (C)2004,JPO&NCIPI