Kabushiki Kaisha Toshiba

Texas Instruments Corporation

Toshiba Samsung Storage Technology Corporation

Toshiba Automation Equipment Engineering, Ltd.

Akihiko Doi

Shengyuan Li

Hideo Ando

Tomohisa Yoshimaru

Mikio Yamamuro

Ryoji Takeuchi

Indumini W Ranmuthu

Tetsuo Saito

Lundy Findlay Taylor

Hiroshi Yamashita

A high frequency modulator is described. It comprises: a first converter for receiving a constant current signal and transmitting a first converted signal; an adder coupled the first converter and operative for transmitting a summed signal in response to receiving the first converted signal and selectively receiving a triangular signal; a first oscillator coupled to the adder for receiving the summed signal, the first oscillator operative for transmitting a time varying current signal; a second converter coupled to the first oscillator for receiving the time varying current signal and operative for transmitting a second converted signal; and an output device selectively coupled to the second converter and operative for transmitting an output signal in response to receiving either the second converted signal or an offset signal.

High frequency modulator

A current gain control system is described and comprises first and second gain blocks respectively associated with the first and second input channels, wherein first and second gain blocks transmit first and second gain signals in response to receiving first and second input signals; first and second converters adapted to be respectively coupled to the first and second gain blocks, the first and second converters operative for setting gains associated with the first and second input channel and for transmitting first and second converted signals in response to receiving the first and second gain signals; and first and second switches for selectively coupling the first and second converters to first and second channel drivers, respectively, wherein the first and second channel drivers transmit channel gain signals in response to receiving the first converted signal, and the channel gain signal allows control of the gain associated with the input channel.

Current gain control system

An optical disc apparatus includes an emitter which emits a laser beam to a optical disc, a divided photodetector including a first dived portion and a second dived portion disposed in a light path of the reflected beam from the optical disc, and producing a first photodetector signal and a second photodetector signal, a phase difference detector which produces a phase difference signal from a phase difference between the first and the second photodetector signals, an integrator which produces a integral signal from a integration of the phase difference signal, a tracking controller configure to perform tracking control based on the integral signal, and a limiter which limits a signal to be supplied from the divided photodetector to the phase difference detector or a signal to be supplied from the phase difference detector to the integrator based on a detection status of a signal detected by the dived photodetector.

Optical disc apparatus including a divided photodetector

An over current protection device is described. It includes a plurality of input channels for receiving an input signal; a plurality of low pass filters coupled to a first group of the plurality of input channels, wherein each low pass filter is associated with one input channel within the first group of input channels, the plurality of low pass filters operative for removing spikes in associated with the input signal; and a plurality of digital to analog converters coupled to a second group of the plurality of input channels, wherein each digital to analog converter is associated with one low pass filter in the second group of input channels, the digital to analog converters operative for triggering over current protection when a signal received from the associated low pass filter is beyond a preset level, wherein the over current protection device is on chip with the laser diode driver.

Over current protection device

A modulation control system for use with a high frequency modulator is described. This system comprises a latch for selectively receiving enable signals, wherein the latch transmits a latched signal in response to receiving at least two of the enable signals; a selection device coupled to the latch for receiving the latched signal, a voltage source, and a terminal for receiving at least one of the enable signals, wherein the selection device transmits a selected signal; and a logic device coupled to the selection device and a terminal for receiving a modulated enable signal, wherein the logic device transmits a synchronized signal for either enabling or disabling the high frequency modulator in response to receiving the selected signal associated with at least one of the enable signals.

HFM enable control system

According to one embodiment, an optical disk device includes a laser light source that emits laser light to be applied to an optical disk, an automatic power control circuit that controls a laser output of the laser light source, and a control processor that performs a setting data transmission process for the automatic power control circuit. The automatic power control circuit includes an operation setting module that makes an operation setting according to setting data obtained in the setting data transmission process of the control processor and a condition determining module that determines whether an operation setting permission condition containing the number of clocks during a transmission period of the setting data is adequate, and inhibits the operation setting of the operation setting module when the operation setting permission condition is not adequate.

Optical disk device and control method

An optical disc apparatus includes an emitter which emits a laser beam to a optical disc, a divided photodetector including a first divided portion and a second divided portion disposed in a light path of the reflected beam from the optical disc, and producing a first photodetector signal and a second photodetector signal, a phase difference detector which produces a phase difference signal from a phase difference between the first and the second photodetector signals, an integrator which produces a integral signal from a integration of the phase difference signal, a tracking controller configure to perform tracking control based on the integral signal, and a limiter which limits a signal to be supplied from the divided photodetector to the phase difference detector or a signal to be supplied from the phase difference detector to the integrator based on a detection status of a signal detected by the divided photodetector.

Optical disc apparatus

An optical disc drive according to an embodiment of this invention includes a light-receiving section for receiving light, a conversion section for converting the light received by the light-receiving section into an electrical signal, a generation section for generating a slewing rate control signal, and a signal processing section for processing the electrical signal using the slewing rate control signal.

Optical disc drive and signal processing method

In an optical disk device with various types of optical disks, the amounts of light are set for the various types of optical disks by emitting laser light from a semiconductor laser oscillator while sequentially increasing the light amount thereof for the optical disks in an order from the optical disk of the smallest set light amount. That is, first, whether or not an optical disk of CD, CD-ROM or DVD-ROM can be suitably used is determined based on the amount of reflection light from the optical disk obtained by causing the semiconductor laser oscillator to emit laser light in the smallest light amount setting state, and if it is not determined that the optical disk can be suitably used, the light amount is raised to a level higher than the lowest light amount set level by one level.

Recording and reproducing optical disk device with multi-disk type

A head signal process circuit 18 generates a focus error signal representing the distance between an optical disc 11 and an objective lens 20 using a detection signal detected by an optical detector of an optical head 14. The focus error signal is sent to a non-linear amplifying circuit 21. The level of the focus error signal in the vicinity of a servo point is amplified. The level of the focus error signal apart from the servo point is suppressed. The output of the non-linear amplifying circuit 21 is sent to an A/D converter 22. Thus, a servo digital signal is generated.

Optical disc apparatus having improved read accuracy with non-linear

A signal processing circuit for a disk apparatus with an optical head, which causes photodiodes to detect light acquired by irradiating light from a laser diode on a disk that has an address portion and data portion recorded thereon, and performs photoelectric conversion of the light. A level converter alters the level of the signal detected by each photodiode and provides an output signal. A detector detects a level of the output signal by switching time constants between the address portion and data portion. Using a bias corresponding to the detected level, the levels of signals detected by the photodiodes are changed.

Signal processing circuit for optical disk apparatus

Disclosed is an objective lens position detecting system which comprises an optical head for holding an objective lens for focusing a light beam on a storage disk having tracks formed thereon, a first detector having a first light-emitting element and a first light-receiving element and provided in a vicinity of the objective lens, unconnected thereto, for detecting the position of the objective lens, a second detector having a second light-emitting element and a second light-receiving element and provided in a vicinity of the objective lens, unconnected thereto, and apart by a predetermined distance from the first detector, for detecting the position of the objective lens, a plate, connected to the objective lens, for reflecting light from the first light-emitting element to the first light-receiving element and reflecting light from the second light-emitting element to the second light-receiving element, whereby the first detector and the second detector detect the position of the objective lens from values of the reflected light, a circuit for outputting a difference between detection signals received from the first detector and the second detector, and a circuit for receiving the detection signals from the first and second detectors and adjusting the amounts of radiation from the first light-emitting element and the second light-emitting element so as to cause the sum of the detection signals to approach a predetermined target value.

Objective lens position detecting system capable of adjusting amounts of

In an information recording system, a semiconductor laser is energized in response to a drive current which is modulated in accordance with a recording signal in a recording mode so that a modulated laser beam is generated from the semiconductor laser. The modulated laser beam is focused on an optical disk and is reflected from the optical disk and the reflected laser beam is detected by an photo-detector. A detection signal from the detector is compared with a predetermined threshold level by a binary circuit and a relationship between the recording signal and an output signal from the binary circuit is detected by a detection circuit. In a overwrite mode in which the laser beam is focused on a pit or pits on the optical disk, an overwrite detection signal is generated from the detection circuit and the overwrite detection signal is counted by a counter circuit. When the counter circuit counts a predetermined count value, the counter circuit generates a recording inhibition signal for preventing the semiconductor laser from generating the modulated laser beam.

System for recording information on an optical recording medium

In an information recording system, a semiconductor laser is energized in response to a drive current which is modulated in accordance with a recording signal in a recording mode so that a modulated laser beam is generated from the semiconductor laser. The modulated laser beam is focused on an optical disk and is reflected from the optical disk and the reflected laser beam is detected by an photo-detector. A detection signal from the detector is compared with a predetermined threshold level which is set in accordance with the peak intensity by a binary circuit and a relationship between the recording signal and an output signal from the binary circuit is detected by a detection circuit. In an overwrite mode in which the laser beam is focused on pit or pits on the optical disk, an overwrite detection signal is generated from the detection circuit and the overwrite detection signal is mounted by a counter circuit. When the counter circuit counts a predetermined count value, the counter citcuit generates a recording inhibition signal for preventing the semiconductor laser from generating the modulated laser beam.

Information recording system capable of preventing overwriting

An information processing apparatus includes a main base and a drive base on which support frames are erected to face each other. A pair of parallel guide shafts are supported on the frames and extend in the radial direction of an optical disk. An optical head is supported by the guide shafts to be movable along the shafts. Insulating tape is wound around each end of the guide shaft to electrically insulate the head from the base, thereby preventing external noise from being transmitted to the head via the base. The drive base is further insulated from the main base by insulating seals interposed between the main base and the drive base and by insulating collars through which screws attach the drive base to the main base.

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Tokyo, Japan

Akihiko Doi