Abstract: An optical pickup objective lens system for collecting a laser beam emitted from a light source onto a recording surface of an optical recording medium includes three lenses having negative, positive and negative powers sequentially, or positive, negative and positive powers sequentially in the order from the side of the light source toward the optical recording medium. The three lenses are bonded to one another through two joint faces, and each of the two joint faces is formed into an aspherical shape. Thus, the chromatic aberration can be corrected satisfactorily. Especially, even when a laser beam having a short wavelength is used, the recording and replaying of information can be carried out reliably and stably.

Abstract: A method of recording information on an information medium, especially on an optical recording medium with light. It has been hard to determine optimum power accurately due to the influence of the linearity and the mark length dependence on rewrite deterioration when a write parameter calibration on a phase change optical disk is performed by a conventional asymmetry method prior to information recording. According to the present invention, a single pattern or a random pattern is recorded on an information medium, and the difference between the clock and the data edge is detected using a reproduced signal. On the basis of this difference, the threshold power of the recording is determined and multiplied by a constant to optimize the recording power.

Abstract: The present disclosure relates to a data storage device, comprising a plurality of electron emitters adapted to emit electron beams, the electron emitters each having a planar emission surface, and a storage medium in proximity to the electron emitter, the storage medium having a plurality of storage areas that are capable of at least two distinct states that represent data, the state of the storage areas being changeable in response to bombardment by electron beams emitted by the electron emitters.

Abstract: A microprobe is provided which comprises a single crystal provided on a part of one main surface of a substrate or a part of a thin film formed on one main surface of the substrate. The microprobe may have a single crystal having an apex portion surrounded by facets having a specific plane direction and comprising a specific crystal face. The method for preparing the microprobe and an electronic device employing the microprobe also provided which is useful for recording and reproducing.

Abstract: An optical disk apparatus equipped with an objective lens for converging light from a light source onto a track formed on an optical disk, the objective lens being arranged to be movable and an error detecting section for detecting a difference in position between the light converged by the objective lens and the track on the optical disk. Included in the servo section of the optical disk apparatus are an amplifier for amplifying an output of the error detecting section with an amplification factor which is variable and a filter circuit for cutting off a frequency component of an output of the amplifying means, the cutoff frequency being variable. On the basis of the output of the filter circuit, a moving device moves the objective lens so that the difference between the converged light and said track is reduced. The amplification factor of the amplifier and the cutoff frequency of the filter circuit are determined in correspondence with the position of the objective lens.