Hitachi, Ltd.

Hitachi-lg Data Storage, Inc.

Other

Hitachi Consumer Electronics Co., Ltd.

Hitachi Video and Information System, Inc.

Hitachi-lg Storage, Inc.

Toshimitsu Kaku

Takeshi Maeda

Kazuo Shigematsu

Yoshito Tsunoda

Akihiro Asada

Takashi Hoshino

Tsuyoshi Toda

Hisataka Sugiyama

Seiichi Mita

Fumiyoshi Kirino

Shigeru Nakamura

Hiroshi Ide

Masaaki Kurebayashi

Hiroyuki Tsuchinaga

Hiroyuki Minemura

Atsushi Saito

Tetsuya Fushimi

Fumio Kugiya

Toru Kawashima

Norimoto Ichikawa

Takehiko Sekine

Motoyasu Terao

Norio Ohta

Masahiro Ojima

Hidehiko Kando

Yasuhito Tanaka

Masahiro Takasago

Shigeki Yamazaki

Hideo Ohnuki

Hirofumi Sukeda

Takeshi Nakao

Shinkichi Horigome

Yasuhide Ouchi

Toshio Niihara

Soichi Isono

Masuo Kasai

Yasushi Fukuda

Hitoshi Komatsu

Yuji Yamane

Toshiaki Ishibashi

Akira Kitayama

Makoto Nihei

Kazuhide Hamada

Yosiho Suzuki

Hideo Oonuki

Hidehiko Kandou

Harukazu Miyamoto

Naoto Matsunami

Yasushi Miyauchi

Tetsuya Nishida

Keiji Kataoka

Koichiro Nishimura

Seiji Yonezawa

Kunio Harada

Kiyoshi Honda

Kunikazu Ohnishi

Masaru Ito

Toshiaki Tsuyoshi

Hajime Nishimura

Takashi Takeuchi

Yukio Fukui

Yoshinori Miyamura

Wasao Takasugi

Takashi Toyooka

Masatoshi Ohtake

Masahiko Takahashi

Eisaku Saiki

Tsuneo Suganuma

Toshimasa Kamisada

Satoshi Kawamura

Takuya Mizokami

Kiyoshi Matsumoto

Yoshio Taniguchi

Akira Saito

Tetsuya Ikeda

Manabu Katsuki

Kazuo Ichino

Keikichi Ando

Shigenori Okamine

Tokuya Kaneda

Hiroshi Yasuoka

Munehisa Mitsuya

Masateru Watanabe

Masahiko Ishimaru

Masanori Matsuzaki

Tsuyoshi Kato

Sakae Ota

Atsushi Saitoh

Kunihiko Kizaki

Nobuhiro Matsumura

Tesuya Nishida

Tsuyashi Toda

Horishi Ide

Masaaki Hishiki

Tuyoshi Kato

A optical pickup includes: a laser diode; a driver including a first output end of a laser diode drive current; a first line electrically connected to the first output end of the driver and a first port of the laser diode; a second line provided adjacent to the signal line at at least one location or more and electrically connected to a second port of the laser diode; a printed circuit board including the first and second lines; and a metal heat dissipation cover for the driver. The first and second lines form a two layer structure in which the first and second lines are vertically disposed. The line width of the line provided close to the heat dissipation cover is wider than the line width of the other line between the first and second lines in the two layer structure.

Optical pickup and optical disc drive

Bandwidth is secured for a read signal transmission line by matching the characteristic impedance of the read signal transmission line with the output impedance of a photodetector of an optical pick up, while at the same time securing bandwidth for the photodetector. In an optical disc drive according to an embodiment of the present invention, each line forming a differential transmission line is divided into a plurality of lines of the same quantity, the quantity being two or more, at or near a connection point between a flexible line and the optical pick up.

Optical disc drive

Pulses modulated between the erase power and the bottom power are used instead of cooling pulses for an optical disk medium that needs a write strategy with 4-valued power levels. Consequently, pulse instruction lines for the cooling pulses, power level instruction lines, and corresponding current source within the laser driver can be omitted. Decrease in size and lower power consumption can be accomplished.

Multiple pulse recording method with 3-valued power levels

Disclosed herein is a technology that enables stable and high-speed writing and/or reading in an optical disk apparatus. The optical disk apparatus has an optical head that includes a first circuit for driving a laser diode, a second circuit for sampling and holding analog electric signals that are based on reflected laser light from the optical disk, and a third circuit for converting said signals being sampled and held into digital signals. Signals digitized in the optical head are transmitted to the apparatus body side using time-division multiplexing. The first circuit, the second circuit, and the third circuit are constructed on a single substrate or in a single IC.

Optical disk apparatus, optical head, and detection signal processing method thereof

Due to the axial runout of an optical disc, a frequency of a high-frequency current to be superimposed onto a DC current could not be maintained. In order to solve the problem described above, a drive signal is generated by superimposing a high-frequency signal onto a DC current, the drive signal is applied to a laser beam light source, thereby the light source is driven; and a servo signal at a signal level corresponding to a defocus amount of the laser beam relative to the surface of the optical disc is generated based on a reflected light of the laser beam from the recording surface of the optical disc, and a low-frequency component of the servo signal is extracted, and thereby the frequency of the high-frequency signal to be superimposed onto the DC current in the light source driver is controlled based on the low-frequency component of the servo signal.

Optical disc device and reproduction method

An optical disk apparatus uses a laser driver which can measure the frequency of the high-frequency superimposed current of the semiconductor laser simply and accurately. The apparatus includes a semiconductor laser which emits a laser beam onto the optical disk, a laser driver which drives the semiconductor laser with a current, with the high-frequency current being superimposed thereon, and measures the frequency of the high-frequency current, and a main controller which controls the frequency of the high-frequency current produced by the laser driver by using the frequency measured by the laser driver.

Laser driver, optical disk apparatus using the same, and laser control method

A laser driver drives a laser diode by producing a write strategy, that is, a recording waveform from a recording clock and a modulated signal. In one embodiment, a laser driver produces the waveform of a driving signal, which is used to drive a laser diode, using a record data signal that represents record data to be recorded on a recording medium. The laser driver comprises an internal clock production circuit that produces an internal clock synchronous with the record data signal, and a strobe circuit that strobes the record data signal according to the internal clock.

Laser driver and optical disk system

A method of recording data into a recording medium by forming a recording region which is physically different from the nonrecorded portions is disclosed. The optical data recording/reproducing method includes a first trial writing operation in which trial writing data are recorded into the recording medium while changing the recording power conditions, the recorded trial writing data are reproduced, and the reproduced trial writing data are evaluated to set an optimum recording power. The method also includes a second trial writing operation in which trial writing data are recorded into the recording medium while changing the servo conditions, the recorded trial writing data are reproduced, and the reproduced trial writing data are evaluated to set optimum servo conditions.

Magneto-optical data recording/reproducing method

An optical information recording and reproducing apparatus that determines the quality of recorded information through a beta value from information on the amplitude of a reproduced signal and if the beta value is outside the permissible range, outputs information on error to a host computer. Immediately after the information is recorded the information is reproduced first and second kinds of information including information on the amplitude of the reproduced signal and performance information or error information obtained from a binarized signal of that reproduced signal, respectively are used to determine the quality of the reproduced signal. Recording power condition is changed based on the first kind of information and a recording pulse width condition or reproduction condition is changed based on the second kind of information to ensure the reliability of the information recorded.

Information recording and reproducing apparatus

An information recording apparatus and method for recording information of a recording block including a plurality of sectors as one verifying unit into an optical information recording medium, a recording area of the optical information recording medium including a plurality of zones, and wherein each zone is different in a sector number per round of a track. A recorder records information of a plurality of recording blocks into the optical information recording medium and a verification conductor conducts a verify control. A number of the recording block included in the verifying unit is determined to be a minimal number in a rotation waiting sector number.

Information recording/reproducing apparatus

Disclosed is an optical recording and reproducing apparatus comprising a light source directing a light spot toward a recording medium, a detection system detecting light reflected from the recording medium to derive an electrical signal from the reflected light, an information processing circuit modulating the intensity of the light spot according to writing pulses to record information on the recording medium and using the electrical signal to reproduce information from the recording medium, and a tracking servo circuit carrying out tracking servo operation on the basis of the electrical signal and including an extracting circuit connected to a source of extracting pulses having a pulse width at least equal to the writing pulse width so that writing pulse parts contained in the electrical signal are extracted during recording information, whereby a track offset occurring during information recording can be minimized, and the stability of the tracking servo system can be improved.

Method and apparatus for optical recording and reproducing with tracking servo reducing track offset

A laser waveform generation function is provided in a laser driving waveform generatornear a laser. A recording clock generatoris included in the laser driving waveform generatorto generate a clock with a frequency higher than that of a synchronizing clock. This allows a recording laser current (waveform) to be generated without transmission of a high frequency signal from the modulatorFurther, because the synchronizing clockis stopped upon a reproduction operation including reproduction operation in an ID unit, undesired effects on a reproduction operation such as ID reproduction can be reduced. Because the response speed of the recording clock generatorcan be changed, a high precision clock can be generated. Thus, a high-precision recording laser current (waveform) can be generated.

Information recording and reproducing apparatus for updating the waveform of a laser based on position information

According to the present invention, in an optical disk apparatus constructed to supply signals for controlling a semiconductor laser drive circuit provided to an optical pickup from a signal processing circuit through a flexible cable, the semiconductor laser drive circuit is so constructed as to generate a drive current signal for the semiconductor laser on the basis of a binary signal and a clock signal which are supplied from the signal processing circuit through the flexible cable and the signal processing circuit is so constructed as to stop supplying the block signal to the semiconductor laser drive circuit through the flexible cable during reproduction of data, and to start supplying the clock signal to the semiconductor laser drive circuit before recording of data.

Optical disk apparatus wherein recording clock signal is stopped being supplied to semiconductor laser drive circuit on optical pickup during reproduction operation

In an optical information recording/reproducing apparatus, in which two sets of circuits (including a comparator and a time counting device (i.e., pulse width detector), and a comparator and a time counting device (i.e., pulse width detector)) are provided for detecting that the fluctuation larger than a comparison level continues in the TE signal for a time period, each being set at the respective comparison level and the time duration, differently, thereby the operation of write or erase onto an optical disc is stopped even if only one of them is detected. Also, a position or location information in the PID portion to be reproduced, being outputted from a PID register , and a location information which is read out by the PID decoder are compared by a comparator , thereby stopping the operation of write or erase onto the optical disc if they are inconsistent with.

Optical information recording/reproducing apparatus

Growing community of inventors

Sagamihara, Japan

Toshimitsu Kaku