Funai Electric Company Ltd.

Yasunori Kuwayama

Tadashi Tachibana

Kazuteru Adachi

Hiroshi Osawa

Shunsuke Sehara

Toyoshi Nogami

Takayuki Ono

Toshiaki Fukui

Ryotaro Nakagawa

Minoru Hirashima

Yoshiaki Ukawa

Shoji Saito

Toshihiko Yamaue

A DSP of the DVD recorder includes a balance value setting portion for determining an appropriate value of a focus balance value &#x3b1; when information is reproduced from an optical disc so as to record the determined focus balance value &#x3b1;in a balance value storing portion and to set the same in a first amplifier of a focus error signal generating circuit, and a correction executing portion for reading the focus balance value &#x3b1;stored in the balance value storing portion when information is recorded in the optical discso as to correct the read value to be a focus balance value &#x3b1;, which is set in the first amplifier of the focus error signal generating circuit.

Optical disc recording and reproducing apparatus

A DSP of a DVD recorder includes: a gain setting portion determining appropriate values of a first gain &#x3b1; and a second gain &#x3b2; when playback of an optical disc is performed, recording the first gain &#x3b1; and the second gain &#x3b2; thus determined in a gain storing portion, and setting them in a main differential amplifier and a sub differential amplifier, respectively; and a correction performing portion reading, when recording on the optical disc is performed, the first gain &#x3b1; and the second gain &#x3b2; stored in the gain storing portion, correcting at least one of them, and setting them in the main differential amplifier and the sub differential amplifier, respectively.

Optical disc recording and playback apparatus

Detection of a wobble cycle of wobble formed at a groove of an optical disc is started. A phase locked loop time that is from reset of phase locked loop circuit until a signal read from the wobble locks is calculated. The focus balance value corresponding to the minimum phase locked loop lock time is set as the focus balance value for ADdress In Pre-groove. When ADdress In Pre-groove information being address information is read, focusing servo control is performed with the focus balance value for ADdress In Pre-groove.

Optical disc apparatus capable of precisely reading address information and method of controlling optical disc apparatus

In an optical disc device that records information on a recordable optical disc having a power calibration area (PCA), recording operation is started with an input of a recording command. If an operating environment changes largely along with the recording operation, in order to perform an optimum recording power control, an optical pickup is shifted to the PCA, and the amount of an unused area in the PCA is determined. If an unused area in an amount to perform an optimum power control five times is not left, the optimum recording power control is stopped, and the recording operation is stopped. If left, the optimum recording power control is executed. Then, if a finalizing process is instructed, the finalizing process is performed. This avoids that, when performing a finalizing process of an optical disc after being subjected to recording, the finalizing process cannot be completed because the amount of an unused area remaining in the PCA is small.

Optical disc device

An optical pickup of an optical disc apparatus has a lens holder for holding an objective lens is pivoted with a guide shaft slidably in a direction in parallel with an optical axis of the objective lens and rotatably around the guide shaft in a direction perpendicular to the optical axis. For focusing a laser beam on a data recording face of an optical disc in a focusing on operation, a wobble signal of rectangular waveform having a predetermined voltage and a predetermined frequency is applied to a tracking coil for reciprocally displacing the lens holder in the direction perpendicular to the optical axis, while a focusing coil is driven for moving the lens holder in the direction in parallel with the optical axis. Thus, the lens holder can be moved smoothly along the guide shaft, so that the possibility of failure of the focusing the laser beam on the optical disc can be reduced drastically.

Optical disc apparatus

In an optical disc apparatus for recording and/or reproducing data on an optical disc, a lens holder for holding an objective lens is dynamically moved not only in a direction perpendicular to a data recording face of an optical disc but also in a direction parallel to the data recording face and crossing substantially at right angle with data recording tracks on the data recording face when the optical disc is loaded on the optical disc apparatus so as to remove the sticking of the movement of the objective lens due to adhesion of dust, break or deformation of the components.

A two-MCU system includes a main-MCU and a sub-MCU. When any one of operating keys is operated, an operation signal is applied to the sub-MCU. Thereupon, the sub-MCU detects the operation of the operating key, and makes a timer start to count a time period. The sub-MCU, when no specified command is received from the main-MCU irrespective of a lapse of a predetermined time period, determines that the main-MCU is being in a hang-up state. Then, the sub-MCU applies a reset signal to a reset circuit thereby to reset the main-MCU, and the two-MCU system returns from the hang-up.

Two-MCU system and hang-up detecting method of MCU

When an optical disc is set to the motor, the slice level is set to a slice level Sk as a reference slice level and a measured jitter value A (S, S) is produced. The slice level is incremented in steps of a fixed quantity Si (S). Then, a measured jitter value B obtained at the incremented slice level is compared with the previous measured jitter value A (S, S). This sequence of process is repeated, and when the measured jitter value A is smaller than the counter value, it is judged that the jitter changes its quantity varying direction to a decreasing direction. Then, the incrementing operation of the slice level is immediately stopped, and the slice level is decremented in steps of another fixed quantity Sd (&#x3c;Si). The previous measured jitter value C is compared with a measured jitter value D after the slice level is decremented (Sto S). When the measured jitter value C is smaller than the counter jitter value, it is judged that the slice level detected at that time is an optimum slice level.

Image reading device for an optical device

With a CD laser, a focusing search is carried out to detect a value CD-FE(pp) which is a difference between a maximum value and a minimum value of a focusing error signal, and to detect a value CD-AS which is a maximum value of a full-added signal. With a DVD laser, the focusing search is carried out to detect a value DVD-FE(pp) which is a difference between a maximum value and a minimum value of the focusing error signal, and to detect a value DVD-AS which is the maximum value of a full-added signal. The value that DVD-FE(pp) is divided by DVD-AS(max), is divided by the value that CD-FE(pp) is divided by CD-AS(max). According to whether the computed result by division is larger or not than a threshold value, it is determined whether the diskis of a CD standard or of a DVD standard.

Disk reproducing apparatus and disk type identifying method

In an optical disc apparatus for reading data from an optical disc, levels of photo-detecting signals outputted from a plurality of photo-detecting areas of a photo-detector are adjusted to be substantially even for canceling error components due to positioning error of the photo-detector on an optical pickup. Analogous signals outputted from the photo-detecting areas of the photo-detector are amplified by amplifiers and converted to digital signals by A/D converters. A processor takes the converted digital signals and adjusts gains of the amplifiers with using the digital signals.

A disk apparatus includes a DSP (digital signal processor), and the DSP controls respective circuit components under instructions of a MCU. During a track jump, a DSP core detects a zero-cross cycle of a TE (Tracking Error) signal just before. If a detected zero-cross cycle is delayed than a target value, the DPS core applies an acceleration pulse of a first predetermined level to a driver, and if the zero-cross cycle is faster than the target value, the DPS core applies a deceleration pulse of a second predetermined level to the driver, whereby an objective lens can be controlled to move at approximately constant speed between adjacent tracks. However, if the zero-cross cycle is considerably delayed than the target value, the DSP core forestalls a reverse rotation of a moving direction of the objective lens against the disk by greatly accelerating the objective lens. Therefore, the number of tracks to have been jumped is not to be counted erroneously.

Track jump control apparatus and track jump method

Focusing balance adjustment of adjusting a servo mechanism is executed so that reproduction quality is optimum in a state where a focusing servo is active (&num;5). Thereafter, tracking balance adjustment of adjusting the servo mechanism is executed so that a tracking balance deviation is cancelled which is an amplitude difference between the upper side and lower side relative to a reference level of a waveform generated in a tracking error signal when the focal point of a light beam applied to the disk crosses a track of the disk (&num;7).

Disk device and method for adjusting servo mechanism

A light-pickup device has a constitution in which a microcomputer executes control for applying offset voltage to a focus error signal by changing over connection of an FE offset circuit when a servo-processor kicks focus drive voltage for acceleration in order to change over information recording layers of an optical disk having two information recording layers on a plane thereof. Then, a signal output level at a zone in which no focus error signal is occurred, does not coincide with focus zero cross. Owing to this constitution, the servo-processor detects focus zero cross point of the focus error signal even in a simple circuit structure.

Light-pickup device applied to a recording and/or reproduction device for an optical disk inluding a detection circuit that generates a focus zero cross signal

In a disc apparatus, a tracking error signal from an optical pickup is outputted to a micro-computer. The micro-computer discriminates a disc that is different in bit density (track pitch) based on amplitude and/or waveform of the tracking error signal.

Disc apparatus with a disc discriminating function

An optical disc apparatus includes a turntable. The turntable is first rotated at a low speed in response to turning on of a reproduce switch on the disc apparatus, and the balancer is, in turn, brought to rest at an optimal position for low speed rotation. When the balancer comes to rest, automatic adjustment is effected. When the automatic adjustment is ended, the turntable is decelerated in rotation to release the balancer from resting. When the rotation speed of the turntable reaches a speed at which the balancer is released from resting, the balancer becomes movable relative to the turntable. Thereafter the turntable is brought into high speed rotation to move the balancer to rest at an optimal position for high speed rotation.

Growing community of inventors

Daito, Japan

Yasunori Kuwayama