Hitachi, Ltd.

Renesas Technology Corp.

Hitachi-lg Data Storage, Inc.

Yukinobu Tada

Yoshinori Ishikawa

Hideo Nishijima

Kaneyuki Okamoto

Masayuki Kijima

Takeo Ohkouchi

Masato Soma

Dan Aoki

Motoyuki Suzuki

Hiroshi Shimizu

Naoki Yamamoto

Tadashi Kuwabara

Yutaka Igarashi

Michio Masuda

Masaru Noda

Hiroyasu Ohtsubo

Shinichiro Fukushima

Kouji Minabe

Kouji Kaniwa

Toru Numata

Hiroya Abe

Yoshio Narita

Mayumi Ueyama

Maki Furui

Rituko Kanazawa

Katsuki Ikuta

Misuzu Mochizuki

A focus jump technique enables focus control on recording layers of a disc in such a manner that its effect is not absorbed by disturbance or a variation in the movement speed of an objective lens. The technique involves monitoring level of a focus error signal and rejecting noise from the error signal. A speed sensor detects movement speed of an objective lens; and a speed control circuit generates a voltage for controlling the objective lens, based on the detected movement speed. Movement speed of the objective lens is detected during focus jump, a corresponding lens drive signal is generated, and an end position is determined from behavior of the error signal immediately before the end of the jump. A focus control is pulled, from a focus point corresponding to one recording layer, into a focus point corresponding to another recording layer forcibly in a stable manner.

Optical disc apparatus switching focus point between layers

An IC provided in an optical disk device having an objective lens and a pickup for a disk. The IC has a circuit for holding a signal which drives the objective lens in a focus or tracking direction and for detecting the moving direction of the objective lens, and a circuit for generating a signal which applies an acceleration to the objective lens. When the objective lens passes through a defect on the disk, on the basis of the detected moving direction of the objective lens, the IC applies the acceleration alternately in plus and minus directions to the objective lens to make the objective lens stationary. As a result, after the defect passage, the objective lens can be quickly returned to a focused point or an on-track position and reproducing/recording operation can be resumed.

Optical disk drive control circuit

Focus point switching

A video recording/reproducing apparatus capable of discriminating commercial message portions even when a broadcasting mode is the same. A magnetic head records television broadcasting signals to a magnetic tape and reproduces the television broadcasting signals from this magnetic tape. When the television broadcasting signals are reduced by recording/reproducing apparatus, an audio-free portion detector detects audio-free portions from audio signals in the television broadcasting signals. Commercial message (CM) portion detector detects the commercial message portions in the television broadcasting signals by the time intervals among a plurality of audio-free portions detected by the audio-free portion detector, and a CM information memory circuit stores the information of the recording positions of the commercial message portions detected by this commercial message portion detector to the magnetic tape. When the television broadcasting signals are reproduced from the magnetic tape, reproduction is carried out while the commercial message portions are skipped, at the recording positions of the commercial message portions to the magnetic tape, on the basis of the information of the recording positions of the commercial message portions to the magnetic tape that are stored in the memory circuit.

Image recording/reproducing apparatus

In a control apparatus for operating with program data, it is possible to alter the operation of a control circuit by rewriting the data of the program memory built in an LSI, with ease and at a low cost independently of the operation of the control circuit. For that purpose, the control apparatus includes a ROM, a SRAM, a means for writing data in the SRAM, a selection means for selecting the output from the ROM or the SRAM in accordance with the addresses supplied to the ROM and the SRAM, and a control means for outputting the addresses to the ROM and the SRAM and operating with the output from the selection means as program data.

Control apparatus for selectively operating with program data from two memories and having a system controller supplying program data and address for writing the data to the second memory

During a normal operation, a tracking control signal from a tracking controller is supplied to an adder via a first switch and to a radial deviation component detector. The radial deviation component detector determines a radial deviation component EC of AC caused by radial deviation of an optical disk from the tracking control signal and supplied that component to the adder via another switch. For a track jump, the first switch is turned OFF, cutting off the tracking control signal. Thus, the radial deviation component EC and a jump pulse signal from a jump signal generator are added together by the adder. However, an offset of the tracking control signal TC detected by a DC component detector is further added. To avoid instability, the track jump is compensated so as to be normally carried out even if a DC offset is added to a tracking control signal.

Optical disk apparatus and method capable of compensating for instability track jump and focus jump

For changing services to readers who desires to obtain electronic books exactly or minutely, an electronic book management systemdistributes at least electronic purchase certificates relating to books which are stocked at a bookstores owing a bookstore terminal device, in advance, to that bookstore terminal device. When buying the book(s), a reader obtains in an IC cardowned by her/him a purchase certificate(s) of that book(s) which she/he bought, from the bookstore terminal. When ordering to obtain the electronic book(s), the reader transmits the purchase certificate(s) from a reader terminal deviceto the electronic book management systemthrough a communication network. The electronic book management systemchanges over it's service when supplying the electronic book(s) to that reader depending upon the existence of the purchase certificate(s).

Electronic book distributing system by use of purchase certificate and devices therefor

Control apparatus and optical disc apparatus using it

On the occasion of stopping the tape running at a high speed, a winding radius of the tape supply reel is detected to set the tape deceleration rate (a) on the basis of the detected winding radius of the supply reel. After the tape running speed is decelerated up to the allowable speed VL in the predetermined deceleration rate (a), the tape is stopped by effectuating the brake. Thereby, the tape can be driven at the speed higher than the allowable speed VL without generating any damage, enabling reduction of time required for the fast-forward/rewind operation. Moreover, application flexibility is improved by providing a couple of tape running modes at the first high speed V1 which is higher than the allowable speed VL and the second high speed V2 which is lower than the allowable speed VL. In addition, running of the tape can be ceased within the predetermined time t from the input of the stop command signal by specifying the maximum speed Vmax depending on the preset deceleration rate (a) and limiting the tape running speed with the maximum speed Vmax.

Tape running apparatus

Growing community of inventors

Yokohama, Japan

Yukinobu Tada