Title:
POSITIONING METHOD OF OPTICAL DISK
Document Type and Number:
Japanese Patent JPS6052971
Kind Code:
A
Abstract:
PURPOSE:To raise a rough positioning accuracy, and also to shorten a positioning time by converting a rough positioning moving extent to a pitch quantity of an external scale, and executing a correction by an eccentricity correcting pitch quantity measured by setting a specified rotational position as an original point. CONSTITUTION:In accordance with a pre-seek position and a seek target position of an optical head, a subtracting circuit 1 generates a moving pitch quantity (a) converted to an external scale pitch quantity and an inside or outside circumferential direction moving signal of a disk. Subsequently, an eccentricity correcting pitch quantity measured by setting a specified rotational position of an eccentric quantity ''0'' as an original point with respect to the pitch quantity (a) is added and subtracted by an adding circuit 2 and a subtracting circuit 3, and becomes a rough moving pitch quantity (b) or (c). These pitch quantities (b), (c) are selected by a multiplexer 4 in accordance with an inside or outside circumferential direction moving signal and stored in a register 5, a rough movement of the optical head is executed exactly and quickly without being influenced by eccentricity, and a positioning time to a target position of the optical head is shortened.
Inventors:
ICHII HIROSHI
OOSHIMA KEN
OKADA HIROO
OOSHIMA KEN
OKADA HIROO
Application Number:
JP16164583A
Publication Date:
March 26, 1985
Filing Date:
September 02, 1983
Export Citation:
Assignee:
FUJITSU LTD
OLYMPUS OPTICAL CO
OLYMPUS OPTICAL CO
International Classes:
G11B21/08; G11B7/085; G11B21/10; (IPC1-7): G11B7/085; G11B21/08
Attorney, Agent or Firm:
Sadaichi Igita