1. Field
The following description relates to a skew adjusting apparatus and an optical disc drive including the same.
2. Description of the Related Art
Optical disc drives are devices configured to emit light to an optical disc and write or read information to or from the optical disc. The optical disc may be a compact disc (CD) or a digital video disc (DVD).
An optical disc reflects a laser beam emitted from an optical pickup that moves in a radial direction of the optical disc. The optical pickup reads data based on a change in a polarization, a phase or a reflectance of the laser beam. The optical disc is clamped onto a turntable that is rotated by a spindle motor.
In order for an optical disc drive including an optical disc to write a signal onto a signal recording surface of the optical disc and read a recorded signal, light emitted from an optical pickup is preferred to be perpendicularly incident on the signal recording surface of the optical disc.
However, since an optical path of the optical pickup or a spindle motor unit on which the optical disc is mounted may be inclined, an optical axis of the optical pickup and the signal recording surface of the optical disc are not perpendicular to each other. In other words, the optical axis of the optical pickup and the signal recording surface may have an angle or a skew therebetween. Such a skew leads to optical aberration. Optical aberration is a phenomenon in that a direction in which light is incident looks different to an observer who moves in a direction perpendicular to the direction in which the light is incident. The phenomenon causes a degradation in the reliability of a read signal. Accordingly, positions of the signal recording surface of the optical disc and the optical pickup are adjusted. The positions that are adjusted are called skew adjustment.
There are two conventional methods of adjusting skew:
One conventional method involves rotating screws provided on both ends of two guide shafts that guide the optical pickup in a radial direction of the optical disc to adjust positions of an optical pickup and an optical disc. The screws are rotated to dispose the optical pickup and the optical disc perpendicular to each other.
The other conventional method uses a spindle motor. In other words, a plurality of coupling screws is coupled to a main base by passing the plurality of coupling bosses through a plurality of coupling bosses formed on a base mold by which the spindle motor is supported to mount the spindle motor on the main base. In this case, a plurality of springs whose both ends are respectively supported by the spindle motor and the base mold are provided around the coupling bosses to adjust the degree of the coupling screws coupled to the main base. Accordingly, an adjustment of the degree of the coupling screws coupled to the main base adjusts a height of the spindle motor to adjust a skew.
However, since the plurality of springs is provided, an assembling process is complex. Due to the complexity of the assembly process, the ability to assemble and productivity are relatively low and production costs are relatively high.