Patent ID: 6292447
Filing Date: 2001-09-18
Classification: G11B

Abstract:
A head of an optical data recording/reproducing device, comprising:a laser source that emits a parallel laser beam;an objective optical system;a deflector rotatably provided between said laser source and said objective lens system, the laser beam emitted by said laser source being incident on said deflector and directed towards said objective optical system;a relay optical system provided between said deflector and said objective optical system, said relay optical system placing a position in the vicinity of a rotation axis of said deflector and a front principal plane of said objective lens to have a conjugate relationship;a detector provided between said deflector and said relay optical system, said detector having a first and a second light receiving portions and an opening, said two light receiving portions being arranged in a first direction in which the laser beam is deflected by said deflector, a part of the laser beam incident on said detector being received by said first and second light receiving portions, another part of the laser beam which passes through said opening being directed towards said objective lens through said relay optical system; anda controller that determines an amount of rotation of said deflector in accordance with amounts of light received by said two light receiving portions.