Reference disk

Abstract

Abstract PURPOSE:To calibrate a mechanical accuracy detecting device with high accuracy without providing a high-accuracy fine adjusting jig by providing displacement quantity grasping means which grasp the quantities of displacement in an axial direction and a radial direction with high accuracy to respective calibration parts for axial displacement, radial displacement, and a focus error output voltage. CONSTITUTION:When a reference disk 1 is loaded on the disk support part of the mechanical accuracy detecting device, its reference surface 3 is in level with the disk surface of an optical disk, and a beam spot is projected on the axial displacement calibration part 4 and brought under focus control so that a Z0 surface is at a focusing position, thereby calibrating the quantity of the axial displacement according to the current output of the detector. Then the beam spot is brought under track control so as to follow and (N)th track groove 8 of the radial displacement calibration part 5, thereby calibrating the quantity of radial displacement. Further, the focus error output voltage calibration part 6 is formed of an annular slanting surface 9 and an objective is driven linearly so as to converge the beam on a calibration reference position 9a, thereby calibrating focus error output characteristics.

Inventors

• 👤 Shinji Hara
• 👤 Takashi Yoshizawa
• 👤 Kanae Kinoshita
• 👤 Masahiko Sakamoto
• 👤 Mitsuhiro Terada
• 👤 Yoji Suzuki

Bibliographic Details