Pioneer Corporation

Pioneer Electronic Corporation

Yuichi Kimikawa

Hitoshi Yamazaki

Shinichi Naohara

Norio Matsuda

Alex Bradshaw

Masakazu Takahashi

Kazushige Kawana

Motoi Kimura

Takashi Suzuki

Takeshi Sato

Hiroyuki Abe

Takao Yoshida

Kenichi Takahashi

Hideaki Watarihana

Morio Nozaki

Katsunori Tamamura

Nobutaka Kawakita

Hiroyuki Matsumoto

Yasuhiro Shinkai

Mitsuo Yasushi

Masatoshi Yanagidaira

Takeshi Matsumoto

Masashi Takano

Takeshi Fukami

A carriage servo apparatus according to the present invention comprises: a carriage for supporting a pickup that records or reproduces information relevant to an information recording face; and a carriage motor for moving the carriage in a direction parallel to the information recording face based on a motor drive signal. This carriage servo apparatus further comprises a microcomputer for detecting a minimum value of a motor drive signal required for moving the carriage from its still state, and setting a motor drive signal when recording or reproducing information, based on the detected minimum value.

Carriage servo method and apparatus for determining and setting a drive signal

Two sum output signals from two sets of the photodetector elements located symmetrically each other with respect to a light-receiving center of the photodetector of the optical pickup are amplified individually by two amplifiers. A focus error signal is generated in accordance with a difference between respective output levels of the two amplified signals. The gains of the two amplifiers are adjusted in accordance with the focus error signal. A predetermined bias voltage is applied to the focus error signal line in the focus servo control means in accordance with the focus error signal.

Focus servo controller with collision avoidance and method therefor

An information recording medium conveyer is provided, which provides countermeasures against power interruptions with high reliability. When a power interruption occurs during a loading operation with a conveying roller, the first unloading operation is initiated. When the outputs from detection sensors satisfy a predetermined condition during the first unloading operation, the process is initialized to cause the conveying roller to initiate a re-loading operation, thereby loading an information recording medium into a tray. On the other hand, when the outputs from the detection sensors do not change in accordance with a predetermined sequence during the re-loading operation, the process initiates the second unloading operation. When the detection sensors have detected the information recording medium during the second unloading operation and then the outputs from the detection sensors satisfy the predetermined condition, the process is initialized to cause the conveying roller to initiate another loading operation, thereby loading the information recording medium into the tray. Even when a power interruption occurs during an unloading operation, the same processing is performed to eject the information recording medium.

Information recording medium conveyer

During an ejecting or unloading operation of an information recording medium by a conveying roller, if detection signals are output from detecting sensors indicating that the object being ejected or unloaded has already been discharged from an insertion hole although it has not, then the insertion hole is closed by the door. If, for some reasons, the door fails to close the insertion hole within a predetermined time, the conveying roller performs a forcible ejecting operation, whereby the object left inside is forcibly ejected to the outside. Thus, ejection or unloading of a medium is carried out without failure.

Information recording medium conveyor

A liquid-crystal tilt servo apparatus in which a reference voltage generating circuit is unnecessary for a liquid-crystal driving circuit and which has a simple circuit configuration and high reliability is realized. The liquid-crystal driving circuit has a DC removing circuit for removing a DC component of a driving signal generated on the basis of a tilt error correction control signal from a control unit and supplying a resultant signal to a liquid crystal device.

Liquid crystal tilt servo apparatus

A focusing bias adjusting apparatus in an optical recording medium playing apparatus, in which a focusing bias adjustment is executed to remove an offset component in a focusing error signal based on each output signal of a split type photodetector in an optical pickup and, thereafter, a tilt adjustment is executed to an optical system so as to maximize a read signal serving as a sum signal of the output signals of the photodetector in order to compensate a tilt angle which is defined by a normal at the irradiating position of a laser beam from the optical pickup on the recording surface of an optical recording medium and the optical axial direction of the laser beam. When the tilt adjusting operation of the optical system of the optical pickup is performed after completion of the focusing bias adjustment, the focusing bias adjustment is executed again.

Focusing bias adjusting apparatus and method in optical recording medium playing apparatus

A focusing control apparatus is designed to perform a focus jumping operation successfully. The apparatus has reading device which irradiates read light to a recording medium,having information recording surfaces formed on at least two layers, respectively, receiving return light of the read light from the recording medium, and generating a read signal; and control device which executes a focus jumping process to generate a drive signal of a focusing actuator to move an optimum light converging position of the read light from one of the recording surfaces to the other based on a focusing error signal that is generated based on the return light. The apparatus further has drop-out detecting device which detects a drop-out of the read signal and vibration detecting device which detects a vibration of the recording medium or reading device. The control device executes the focus jumping process only when the drop-out is not detected and a vibration detection level of the vibration detecting means is lower than a predetermined value.

Focusing control apparatus for optimally directing light onto a recording surface

A focus control apparatus for a multilayer optical recording medium which performs an appropriate focus jump on a multilayer optical recording medium. This focus control apparatus implements such focus jump control as to temporarily release a focus servo on one layer of a loaded multilayer optical recording medium, shift the focus position of read light on another target layer and then restart the focus servo on the another target layer, detects an ambient temperature, sets a drive signal condition according to the temperature detection output, and moves the focus position of the read light under the set drive signal condition. Specifically, this apparatus generates an acceleration signal to start moving the focus position of read light and a deceleration signal to decelerate movement of the focus position of the read light, as drive signals for a focus actuator in order to execute a focus jump operation, detects an ambient temperature of the focus actuator, and sets signal conditions for the acceleration signal and the deceleration signal according to the detected temperature.

Focus control apparatus for multilayer optical recording medium

Apparatus and method for focus control are devised to cope with a fluctuation of an optimum gain of a focus servo loop due to a difference between light reflectance of recording surfaces or the like and to allow an optimum focal position of read light to preferably trace a target recording surface. The focus control apparatus of the invention includes: reading device for generating a read signal of a recording medium 1; a focus servo loop for allowing an optimum converging position of the read light to trace the target recording surface in accordance with a focus error signal FE by using a focusing actuator to displace the optimum converging position of the read light in the optical axial direction; a level detecting unit of the read signal; a level detecting unit of an error signal FE; amplifiers and of a read signal RF and the error signal FE; and a control unit for driving the actuator so as to allow the optimum converging position of the read light to approach the recording surface in the set-up mode and for controlling gains of the amplifiers so that a detection level by the detecting unit in the set-up mode reaches a predetermined level and a detection level by a detecting unit reaches a predetermined level.

Apparatus and method for focus control of read light irradiated on a

Disclosed is a focus control apparatus of the present invention capable of successfully performing an accurate focus jump operation without an erroneous operation of a focus actuator. The apparatus irradiates a light beam onto a recording medium, and generates a focus actuator drive signal for moving an optimized light convergence point of the light beam from one recording surface to the other, based on a focus error signal generated based on a returned light from the recording medium. The focus control apparatus comprises a detector for detecting that the focus error signal crosses a predetermined level as a specified level crossing; instruction means for generating a focus jump instruction; a drive signal generating means for generating the drive signal in response to the focus jump instruction and receiving a detection output from the detection circuit to recognize a timing of a specified level crossing of the focus error signal upon receipt of the detection output, thereby extinguishing the drive signal at the timing of the specified level crossing detection timing; and inhibiting means for inhibiting the recognition of the specified level crossing by the drive signal generating section for a predetermined period in response to the focus jump instruction.

Focus control apparatus

Sensors are provided for detecting brain waves of a user, and a band-pass filter is provided for extracting a particular brain waves including an .alpha. wave included in a detected brain wave. The band-pass filter comprises a first band-pass filter having a narrow pass band, and a second band-pass filter having a wide pass band. One of the first and second band-pass filters is selected, and a stimulation signal is produced in dependency on an .alpha. wave extracted by a selected band-pass filter. In accordance with the stimulation signal, a stimulation light is emitted to the user in order to induce the user to relax or sleeping state.

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Kawagoe, Japan

Yuichi Kimikawa