Abstract: An optical head for optical storage, having an optical scanner for scanning a laser beam in a recording region, an objective lens of large aperture for collecting all scanned laser beams, and a method for detecting and correcting the focus error and tracking error, a light source and photodetector, in which the objective lens is fixedly set up and the photodetector is placed at the conjugate point of the focal point of laser beam on the recording media. The laser beams reflected from the media are always collected at the center of photodetector, out of relation to the scan angle, thereby reading uniformly the information from the recording media and it is not necessary to move the objective lens. Therefore, access time can be very short.

Abstract: A control system for a washing machine which controls an induction motor to generate an optimum torque in accordance with a load amount of laundry and whether the washing machine is operating in a washing or drying mode. The control system drives the motor at an optimum torque by varying the input voltage in accordance with the sensed load and sensed mode of operation. This allows a washing machine according to the invention to operate more efficiently and with less noise than conventional washing machines.

Abstract: A laser pick-up device for an optical disk receives three laser beams to irradiate the optical disk and uses a six-division optical detector to detect the laser beams reflected from the optical disk and to track exactly the optical disk. A reflection type diffraction grating is positioned at a front position in order to divide and reflect the laser beam generated by a laser diode. A holographic element having the function of a toric lens is used as a diffracting device for the reflected beams. The six-division optical detector is positioned to one side and/or behind the diffraction grating. The grid gaps of the holographic element can be larger using the present invention which simplifies the manufacturing the holographic element and thereby provides a laser pick-up device that is suitable for mass production.