Abstract:
A method for minimum deflection acceleration point detection and focus pull-in and layer jump, and an optical disk actuator executing the method are provided to perform stable focus pull-in and to minimize collision between a disk and an objective lens by executing the focus pull-in at the minimum deflection acceleration point of the loaded disk. A disk loaded in an optical disk actuator is rotated(1001). A first minimum deflection acceleration point of the disk is detected during the first rotary duration of the disk(1002). A second minimum deflection acceleration point of the disk is detected during the second rotary duration of the disk(1003). The first minimum deflection acceleration point is detected by using a surface layer of the disk and symmetry of the data layer based on the phase by which the moving direction of the objective lens is switched when moving the objective lens upward and then moving the lens downward. The second minimum deflection acceleration point is detected by using the surface layer of the disk and symmetry of the data layer based on the phase by which the moving direction of the objective lens is switched when moving the objective lens downward and moving the lens upward.
Abstract:
A motor driving apparatus includes a rectification unit which rectifies an AC voltage and an alternating current which are supplied from a power supply into a DC voltage and a direct current; a smoothing unit which removes a ripple which is included in the direct current and the DC voltage; a power changing unit which provides a driving current for a motor by receiving a direct current from the smoothing unit and converting the direct current into an alternating current; and a control unit which selects any one among multiple PWM modes according to the driving current and controls the power changing unit by the selected PWM mode. Therefore, the motor driving apparatus is able to minimize a power loss caused by a power changing unit.
Abstract:
광디스크에 대한 기록/재생 장치 및 방법이 개시된다. 개시된 기록/재생 장치는, 광정보저장층을 구비하는 광디스크에 대한 기록/재생 장치에 있어서, 참조광의 초점을 상기 광정보저장층 내에 형성시키기 위한 것으로, 상기 광디스크와 마주하는 대물렌즈를 포함하는 참조광 광학계; 신호광의 초점을 상기 광정보저장층 내에 형성시키기 위한 것으로, 상기 대물렌즈를 포함하는 신호광 광학계; 상기 광디스크에 서보광을 조사하고 반사된 광을 수광하여 상기 대물렌즈의 포커싱 및 트랙킹 제어를 수행하는 서보 광학계;를 포함하며, 상기 참조광 광학계는 상기 참조광의 초점을 이동시키는 제1초점이동부를 구비하고, 상기 신호광 광학계는 상기 신호광의 초점을 이동시키는 제2초점이동부;를 구비하여, 참조광의 초점과 신호광의 초점이 일치하는 제1초점위치를 상기 광정보저장층 내에서 상기 광정보저장층의 두께 방향으로 이동 형성하며 정보를 기록함으로써, 복수의 기록층으로 정보를 기록한다.
Abstract:
An apparatus and a method for controlling focus between layers in a high-density multilayer disk are provided to stabilize focus servo control of an optical pickup by holding a focus driving signal regardless of an actual focus error signal. An apparatus for controlling focus in a high-density multilayer disk(D) during a focus jump operation comprises an optical pickup(15), a signal processing unit(20), a focus hold unit, a focus servo control unit(32), and a driving unit(40). The optical pickup comprises an objective lens(17) for collecting light on the disk, an aberration compensation unit(19), and an optical detector(18) for detecting the light reflected from the disk. The signal processing unit generates a focus error signal from the detection signal from the optical detector. The focus hold unit holds focusing servo of the optical pickup, comprising a focus error signal hold unit(25) for holding the focus error signal from the signal processing unit, a first switch(27) for switching connection between the signal processing unit and the focus servo control unit, and connection between the focus error signal hold unit and the focus servo control unit, a focus driving signal hold unit for holding a focus driving signal outputted from the focus servo control unit, and a second switch for switching connection between the focus servo control unit and the driving unit, and connection between the focus servo control unit and the focus driving signal hold unit. The focus servo control unit controls the focusing servo of the optical pickup by using the focus error signal. The driving part drives the optical pickup by using a signal outputted from the focus servo control unit.