PARTS FOR DIGITAL DISK SIGNAL READER, SIGNAL READER USING THE SAME AS WELL AS METHOD FOR STABILIZING SERVO CHARACTERISTIC OF READER

摘要

PROBLEM TO BE SOLVED: To provide parts for a reader which has a gain allowance of =20 dB of a servo circuit and is less or is entirely free of reading errors in spite of widening a servo band and a reader using the same as well as a method for stabilizing the servo characteristics of the reader. SOLUTION: Liquid crystal polymers satisfying the following conditions: loss coefft. x modulus of elasticity 70 MPa and (modulus of elasticity/sp. gr.)1/2 70 MPa1/2 , thermoplastic resins, such as polyphenylene sulfide resins, polyester resins and polycarbonate resins, or their composite resins or thermoplastic resin compsns. prepd. by adding glass fibers, glass beads, carbon fibers or inorg. fillers to these resins are used as the materials of the parts, such as lens holders, bearings, bobbins, sliding shafts and/or actuator bodies, constituting the signal reader of a digital disk driving device.