Abstract: An optical head in which a graded index (GRIN) lens is provided. The optical head includes a slider connected to an arm and flying a predetermined distance above a recording layer for data recording, a GRIN lens mounted in the slider for focusing an incident beam to form a light spot of a predetermined size on its exit surface adjacent to the recording layer, and a light-emitting unit for emitting the incident light to the GRIN lens.

Abstract: An apparatus and method for measuring an aperture of a near-field optical probe is provided. The apparatus includes a light source, an optical detector, and a filter. The light source radiates light to the near-field optical probe. The optical detector is positioned before the near-field optical probe and receives the light transmitted through the near-field optical probe to detect light intensity. The filter is disposed between the light source and the optical detector and transmits only light of wavelengths in a specific mode from the light transmitted through the near-field optical probe. Thus, an aperture diameter of the near-field optical probe can accurately be measured in real-time without damaging the near-field optical probe.

Abstract: An apparatus and method for measuring an aperture of a near-field optical probe is provided. The apparatus includes a light source, an optical detector, and a filter. The light source radiates light to the near-field optical probe. The optical detector is positioned before the near-field optical probe and receives the light transmitted through the near-field optical probe to detect light intensity. The filter is disposed between the light source and the optical detector and transmits only light of wavelengths in a specific mode from the light transmitted through the near-field optical probe. Thus, an aperture diameter of the near-field optical probe can accurately be measured in real-time without damaging the near-field optical probe.

Abstract: An optical head in which a graded index (GRIN) lens is provided. The optical head includes a slider connected to an arm and flying a predetermined distance above a recording layer for data recording, a GRIN lens mounted in the slider for focusing an incident beam to form a light spot of a predetermined size on its exit surface adjacent to the recording layer, form a light spot of and a light-emitting unit for emitting the incident light to the GRIN lens.

Abstract: An electronic expansion valve for a cooling cycle includes a valve housing having intake and exhaust holes and an orifice formed on the exhaust hole. A case is disposed on the valve housing, and a motor is disposed within the case. The motor has a drive shaft extending inside the valve housing. A guide tube is disposed inside the valve housing, the guide tube being vertically or axially movable by rotation of the drive shaft. A needle valve is provided for adjusting an opening of the orifice, the needle valve being mounted on the guide tube. A mechanism is then provided for restricting an axial or vertical movement range of the guide tube and the needle valve, the mechanism being disposed on the drive shaft and the guide tube.

Abstract: A hemispherical bearing apparatus includes a MoS.sub.2 layer formed to a predetermined thickness on the surface of a hemispherical recessed portion formed in a bushing or on the surface of a hemispherical member opposed to the recessed portion. The hemispherical bearing apparatus is capable of enhancing the productivity and reducing the fabrication cost. The method for forming the MoS.sub.2 layer may vary with the material of the bushing and the hemispherical members. The MoS.sub.2 layer may be applied by a coating technology or an impregnating technology.