Patent ID: 8537651
Filing Date: 2013-09-17
Classification: G11B

Abstract:
1. An optical disc device, comprising: an optical source that emits an optical beam; an objective lens that focuses the optical beam on an optical disc; an incident intensity control circuit that controls an intensity of the optical beam emitted from the optical source; a control circuit that controls the incident intensity control circuit such that the intensity of the optical beam is varied once to a third optical beam intensity to be present in between a first optical beam intensity and a second optical beam intensity when the intensity of the optical beam is varied from the first optical beam intensity as a predetermined optical beam intensity up to the second optical beam intensity different from the first optical beam intensity by the incident intensity control circuit; an optical detector that receives the optical beam reflected from the optical disc; and a servo signal generation circuit that generates a focus error signal from the optical detector, wherein the control circuit has a function for controlling the incident intensity control circuit such that a displacement of the focus error signal is present in a predetermined range, when the intensity of the optical beam is varied from the first optical beam intensity to the third optical beam intensity.