JP2002123957A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk device capable of stably reading data by securing sufficient servo performance even in a bad disk. SOLUTION: A PWM system is used for the driver 108 of an actuator 104, a boosting DC/DC converter 112 capable of boosting the power supply voltage of the driver 108 is used, the partial wobbling/partial eccentricity/uneven center of gravity of a loaded disk is detected and, according to its level, the power supply voltage of the driver 108 is switched.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device which is connected to a computer or the like and records / reproduces an optical disk.

[0002]

2. Description of the Related Art In recent years, an optical disk device has played an important role as a basic product of multimedia, and a CD / DVD-ROM drive device as a reproducing device, a CD-R / RW drive device as a recording device, and the like are related to personal computers. It is indispensable as a peripheral device. Further, as next-generation recording devices, DVD-RAM drive devices and ultra-high-density optical disk drives in which the wavelength is shortened and the storage capacity is greatly improved have been developed one after another.
Along with this, application software that handles large-capacity data such as image data is increasing, and demand for higher speed is correspondingly increasing. In recent years, a drive device having a reproduction speed of 20 to 30 times speed has become a common sense, and a demand for a further higher speed has been increasing. On the other hand, applications emphasizing portability are diversifying year by year, and demands for thin drive devices that can incorporate the above performance into a notebook computer are also increasing.

[0003]

However, when trying to realize the above performance with a conventional thin drive device, there were the following problems. Discs such as CDs and DVDs are required to be produced as inexpensively as possible because they are mass-produced. Therefore, subtle variations in accuracy at the time of production may cause poor factors such as partial surface runout, partial eccentricity, and eccentricity. There are many discs on the market. Such a disk does not cause much problem at the time of low speed, but under the condition of a high speed as described above, extreme runout and eccentric acceleration are generated as a disk disturbance. On the other hand, in terms of the configuration of a thin drive device, the supply voltage from the main body personal computer is limited to 5V due to the specifications. The current actuator, especially the thin actuator corresponding to the thin drive device, has a physical limitation in AC sensitivity. When trying to cope with the above-described disturbance at high speed, the maximum thrust determined by the power supply voltage × actuator sensitivity results in an absolute shortage of thrust. That is, the servo cannot be performed with sufficient accuracy, or the servo is deviated, and satisfactory data reproduction characteristics cannot be obtained.

[0004] In view of the above-mentioned conventional problems, the present invention provides low power consumption, low cost, and space saving in recording / reproducing at a high speed and without taking special measures for increasing the sensitivity of the actuator. It is an object of the present invention to realize an optical disk device that secures sufficient servo performance against disturbance caused by a bad disk and enables stable data reading.

[0005]

In order to solve the above-mentioned problems, an optical disk apparatus according to the present invention comprises an optical pickup for reproducing or recording information from a disk via an objective lens, and a micro-displaceably supporting the objective lens. Actuator, a servo controller for performing focus control and track control of the object based on a signal reproduced from the optical pickup, and an actuator for controlling the actuator based on an output of the servo controller.
It has an actuator driver driven by the WM method, a booster that controls the power supply to the actuator driver so as to be able to boost the voltage, and a controller that controls the entire device, and the controller is based on a signal reproduced from the optical pickup. To measure the deviation between the focus error signal and the track error signal.
An optical disk device characterized by controlling a booster based on a result of deviation measurement.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claims 1 to 5 of the present invention supports an optical pickup for reproducing or recording information from a disk via an objective lens, and supports the objective lens so as to be capable of minute displacement. An actuator, a servo controller that performs focus control and track control of an object based on a signal reproduced from an optical pickup, an actuator driver that drives the actuator by a PWM method based on an output of the servo controller, and an actuator driver And a controller that controls the entire apparatus, and the controller measures a deviation between a focus error signal and a track error signal based on a signal reproduced from the optical pickup. An optical disk device wherein the booster is controlled based on the result of the deviation measurement.

According to the present invention, in recording / reproducing at a high speed, it is possible to reduce a partial surface deflection, a partial eccentricity, a low power consumption, a low cost, a small space, and an ultra-high sensitivity of an actuator. It has the effect of suppressing the deterioration of servo performance due to the center of gravity or the like, and enabling stable data reading.

In particular, the invention according to claims 2 to 5 is characterized in that, in the optical disk device according to claim 1, the deviation is measured based on the difference between the deviation at low speed rotation and the deviation at high speed rotation. Wherein a deviation of a focus drive signal or a track drive signal is measured to perform deviation measurement, and a booster varies a supply voltage stepwise by a controller. The booster linearly varies the supply voltage according to the result of the deviation measurement by the controller.

According to the present invention, the function of claim 1 can be strictly achieved by accurately detecting the characteristics of the disk. Also, the operation of claim 1 can be strictly performed with the minimum current consumption according to the level of the disk's feature.

(Embodiment 1) FIG. 1 shows a configuration diagram of an optical disk device according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 101 denotes a disk on which information signals are recorded at a constant linear velocity, and 102, a spindle motor on which the disk 101 is mounted and rotates. Reference numeral 103 denotes an optical pickup, which is an objective lens for condensing a laser beam on the recording surface of the disk 101, and which has an objective lens in a direction perpendicular to the surface of the disk 101 (hereinafter, referred to as a focus direction) and in a radial direction of the disk 101 ( An actuator 104 for moving in the track direction), various prisms including a semiconductor laser, detectors for signal detection, and the like are integrally formed. An RF amplifier 105 generates a servo signal such as a focus signal and a track signal and a data RF signal from an optical pickup output. Reference numeral 106 denotes a servo processor (hereinafter, referred to as DSP) that performs servo control of focus, track, and the like based on a servo signal. Reference numeral 107 denotes a pulse width modulation (Pulse) for driving the actuator 104 based on the output of the DSP 106.
This is an actuator driver of a wide modulation (hereinafter referred to as PWM) method. Reference numeral 108 denotes a spindle motor driver that drives the spindle motor based on the DSP output. 109 is a CPU for managing the operation of the entire apparatus
It is. Reference numeral 110 denotes a low-pass frequency filter (Low Pass Filter, hereinafter referred to as LPF) for removing a high frequency component of a focus error signal (hereinafter, referred to as an FE signal) or a track error signal (hereinafter, referred to as a TE signal) generated by an RF amplifier.
(Or P / H that holds the peak of the error signal)
Circuit). An A / D converter 111 converts the output of the LPF 110 (or the output of the P / H circuit 110) into a digital value. Reference numeral 112 denotes a step-up DC / DC converter capable of increasing the power supply voltage of the actuator driver 108 according to a command from the CPU 109.

The optical disk device according to the first embodiment of the present invention configured as described above will be described with reference to FIGS. 2 is an operation flowchart of the optical disk device of FIG. 1, FIG. 3 is an operation explanatory diagram of the optical disk device of FIG. 1, and FIG. 4 is an operation explanatory diagram of the optical disk device of FIG.

In the initial startup state after loading a disc, first, the optical pickup 103 is moved to a disc reference position (for example, the innermost circumference).
While the spindle motor 102 is driven at a low speed, the CPU 109 measures the deviation of the FE and TE signals based on the output of the RF amplifier 105. The measured values are referred to as FO1 and TR1, respectively.

Next, the spindle motor 102 is driven at a higher speed, and the deviation of the FE and TE signals is measured in the same manner. The measured values are FO2 and TR2, respectively. As described above, even if the disk has a disturbance factor, the servo sufficiently follows at a low speed, since the disturbance acceleration is small. However, at a high speed, the servo loses the disturbance acceleration and has a large deviation. Therefore, by comparing FO1 with FO2 and TR1 with TR2, it is possible to detect the degree of partial surface deflection or partial eccentricity (including the eccentricity) based on the degree.

In the normal contact and eccentricity, since the entire disk has a feature in accordance with a substantially uniform pattern, it is possible to estimate the state of the entire disk by measuring one portion of the disk. However, partial surface contact and partial eccentricity
In most cases, the disk is partially deformed due to mechanical or environmental factors after the disk is created, and the characteristics often differ depending on the location. Therefore, by dividing the radial direction of the disk into zones in advance and performing this measurement for each zone, it is possible to take a sequence for grasping the state of the entire disk at the time of initial startup.

For example, in the example of the normal disk shown in FIG. 3, FO1 and TR1 at low double speed are almost equal to FO2 and TR2 even at a predetermined target double speed.
Naturally, the disc is determined to be a normal disc. On the other hand, in the example of the disk with partial runout, partial eccentricity, and eccentricity in FIG. 3, the FO2 or TR2 significantly increases periodically as the rotation speed increases. The increase is caused by FO2 >> FO1 or TR before reaching the target double speed.
2 >> TR1. Therefore, as shown in FIG. 2, in the case of FO2 >> FO1, it is determined that partial surface deflection has occurred,
The power supply voltage of the focus driver 108 is boosted. On the other hand, when TR2 >> TR1, it is determined that partial eccentricity / eccentricity is present, and the power supply voltage of the truck driver 108 is increased.

As described above, in response to a command from the CPU 109, the power supply voltage on the focus driver 108 side by the step-up DC / DC converter 112 for a partial surface deviation disk, and the track driver side for a partial eccentric (eccentric) disk. Are respectively boosted to required levels. The boost level is set, for example, to a worst disk that must be reproduced in advance, and set to a power supply voltage that can provide a thrust exceeding a disturbance acceleration generated at the time of target rotation in the disk. As described above, it is possible to perform a stable servo even if various bad disks are played at a high speed.

Further, the boost DC / DC converter 112
There are a type in which switching can be performed with no boosting / fixed boosting voltage by an external command, and a type in which switching can be performed with no boosting / specified voltage by an external command. For example, when a partial surface vibration is taken as an example, a level x having a partial surface vibration degree
At the point in time when the value exceeds 1 (= the point in time when the servo characteristics cannot be secured with the supplied power supply is set in advance), FIG.
It is conceivable to use stepwise switching as shown in (a), and in the case of the latter type, after the voltage exceeds x1, the boosted voltage value is linearly varied according to the level.
The usage as shown in (b) is also conceivable. In the latter case, the above-described performance can be realized with a minimum necessary current consumption according to the partial surface runout level.

Here, the reason why the PWM type driver is applied to the driver 108 of the actuator 104 will be described. In a state where full driving is not performed, a driver of the PWM system turns off a power supply with a corresponding duty, and simultaneously uses a back electromotive force energy generated by itself for driving power in an off state. It requires much better efficiency characteristics than linear drivers. Therefore, by minimizing the output current of the power supply, the supply capability of the booster DC / DC converter 112 can also be suppressed, and the above-described embodiment can be realized with a compact and inexpensive configuration.

As described above, according to the present invention, the characteristics of the disk are detected from the difference between the servo deviations at low and high speeds, and the boost control of the power supply voltage is performed. By applying the present invention, in recording / reproducing at high speed, low power consumption, low cost, space saving, and without increasing the sensitivity of the actuator, it is possible to prevent disturbance caused by a bad disk. It is possible to realize an optical disk device that secures sufficient servo performance and enables stable data reading.

(Embodiment 2) FIG. 5 shows a configuration diagram of an optical disk device according to Embodiment 2 of the present invention. In FIG. 5, the components and their functions are the same as those in FIG. The difference from FIG. 1 is that a focus drive signal (FODRV) and a track drive signal (TRDRV), which are output signals of the DSP 106, are used as input signals of the LPF (or P / H circuit) 110.

With respect to the optical disk device according to the second embodiment of the present invention configured as described above, a servo control operation will be particularly described with reference to FIGS. 6 is an operation flowchart of the optical disk device of FIG. 5, and FIG. 7 is an operation explanatory diagram of the optical disk device of FIG. Explaining step by step, in the initial startup state after loading the disc,
The CPU 109 moves the pickup to a disk reference position (for example, the innermost circumference), and drives the CPU 109 based on the output of the DSP 106 while the spindle motor is driven at a low speed.
The deviation of the ODRV and TRDRV signals is measured.

The measured values are assumed to be FO1 and TR1, respectively. Discs with surface runout and eccentricity components have deviations in the drive signal even when servo is applied sufficiently at low double speed (even when servo deviations are not visible).
1. By measuring TR1, it is possible to detect the degree of partial surface deflection or partial eccentricity depending on the degree without the comparison with the case of the high-speed operation as in the first embodiment (however, the eccentricity). It is necessary to compare the speed at low speed and the speed at high speed.) As in the first embodiment, the normal touching and eccentricity have a feature that the entire disk follows a substantially uniform pattern. Therefore, it is possible to estimate the overall state by measuring one part of the disk, but partial contact and partial eccentricity may be caused by a part that has been partially deformed by mechanical or environmental factors after the disk was made. Most of them have different features depending on the location. Therefore, the radial direction of the disc is divided into zones in advance,
By performing this measurement for each zone, it is possible to take a sequence for grasping the state of the entire disk at the time of initial startup.

For example, in the example of the normal disk shown in FIG. 7, FO1 and TR1 are at a very low level even at a low double speed, and are naturally determined to be normal disks. On the other hand, in the example of the disk with partial runout and partial eccentricity in FIG. 7, FO1 or TR1 significantly increases periodically even at a low speed. Therefore, as shown in FIG.
If the FO1 is large, it is determined that the partial surface deflection has occurred, and the power supply voltage of the focus driver 108 is increased. On the other hand, TR1
Is large, the partial eccentricity is determined, and the power supply voltage of the truck driver 108 is increased.

As described above, the power supply voltage of the focus driver 108 by the step-up DC / DC converter 112 for a partial surface deviation disk and the power supply voltage of the track driver 108 for a partial eccentric disk according to a command from the CPU 109. Boost the required level. As a result, the required maximum thrust for the generated disturbance acceleration can be secured, so that a stable servo can be applied.

As described above, the present invention controls the power supply voltage by detecting the identity of the disk from the drive signal deviation at a certain speed. This is because the disk runout and partial eccentricity can be detected by the drive signal. By applying the present invention, in recording / reproducing at high speed,
An optical disk that is low-power, low-cost, space-saving, and secures sufficient servo performance against disturbances caused by a bad disk, and enables stable data reading without increasing the sensitivity of the actuator. The device can be realized.

(Embodiment 3) FIG. 8 is a detailed block diagram of the driver, and the driver 107 shown in FIGS.
FIG. 3 is a detailed configuration diagram corresponding to FIG. Driver 801 in the figure
Is a configuration in which a boost function is added to a general linear input / PWM output type driver (FIG. 8 shows a configuration having only one system, but also includes a configuration having a plurality of systems including focus / track). . 802, an input amplifier for inputting an analog control signal from the DSP 106; 803, a triangular wave oscillation circuit for determining the basic frequency of PWM; 804, a PWM for generating a PWM switching timing based on the output of the input amplifier 802 and the output of the triangular wave oscillation circuit 803;
It is a control circuit. Reference numeral 805 denotes a pre-driver that receives the output of the PWM control circuit 804 and generates a drive pulse, and 806 denotes a power MOSFET that receives the output of the pre-driver 805 and drives an output load.

Reference numeral 807 denotes a step-up DC / DC converter capable of boosting the power supply to the power MOSFET 806.
The boost DC / DC converter 807 is configured to be capable of switching the boost ON / OFF or the boost level for each system in response to an external command.

Here, the PWM type driver and the boost D
Since the basic configuration of the C / DC converter is a known technique, the detailed description is omitted. By applying the driver having the above configuration to the optical disc device, the above functions can be realized as a drive in a compact configuration, and at the same time, a noise loop from a high-voltage and large-current circuit to the actuator via the actuator driver is reduced. Since the distances can be combined, the drive device can be advantageously configured in terms of S / N.

Further, since the actuator can be driven by performing both the modulation of the pulse width and the pulse voltage (pulse amplitude), it is possible to realize high sensitivity without taking special measures for the actuator, and Servo performance can be ensured.

As described above, by applying the present invention,
In recording / reproducing at high speed, high S / N, low power consumption, low cost, ultra-small space, and without any special ultra-high-sensitivity measures against actuators, it is possible to reduce the disturbance caused by a bad disk. To ensure sufficient servo performance,
It is possible to realize an optical disk device that enables stable data reading.

[0031]

As described above, according to the present invention, in recording / reproducing at a high speed, low-consumption, low-cost, space-saving and ultra-high sensitivity actuators can be used. Therefore, an optical disk device that secures sufficient servo performance against disturbance caused by the above and enables stable data reading can be configured.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical disk device according to a first embodiment of the present invention.

FIG. 2 is an operation flowchart of the optical disk device of FIG. 1;

FIG. 3 is an explanatory diagram of the operation of the optical disk device of FIG. 1;

FIG. 4 is an explanatory diagram of an operation of the optical disk device of FIG. 1 for a bad disk.

FIG. 5 is a configuration diagram of an optical disk device according to a second embodiment of the present invention.

FIG. 6 is an operation flowchart of the optical disk device of FIG. 5;

FIG. 7 is a diagram illustrating the operation of the optical disk device of FIG. 5;

FIG. 8 is a configuration diagram of a driver of the optical disc device according to the third embodiment of the present invention.

[Explanation of symbols]

101 Disk 102 Spindle Motor 103 Optical Pickup 104 Actuator (Focus Actuator and Track Actuator) 105 RF Amplifier 106 DSP (Servo Processor) 107 PWM Driver 108, 801 Driver 109 CPU 110 LPF or P / H Circuit 111 A / D Converter 112, 807 Step-up DC / DC converter 802 Input amplifier 803 Triangular wave oscillation circuit 804 PWM control circuit 805 Pre-driver 806 Power MOSFET

Claims (5)

[Claims] 1. An optical pickup for reproducing or recording information from a disk via an objective lens, an actuator for supporting the objective lens so as to be capable of being displaced minutely, and an object for reproducing the information based on a signal reproduced from the optical pickup. A servo controller that performs focus control and track control; an actuator driver that drives the actuator by a PWM method based on an output of the servo controller; and a booster that controls a power supply to the actuator driver so as to be able to boost the power. And a controller that controls the entire apparatus, wherein the controller performs a deviation measurement between a focus error signal and a track error signal based on a signal reproduced from the optical pickup, and based on a result of the deviation measurement. An optical disk device characterized in that the booster is controlled by a controller. 2. The method according to claim 1, wherein the deviation is measured by measuring a deviation of a focus error signal or a track error signal when the disk is rotated at a low speed and a high speed, and calculating a difference between the deviation at a low speed and the deviation at a high speed. 2. The optical disk device according to claim 1, wherein a deviation is measured. 3. The optical disk apparatus according to claim 1, wherein the deviation measurement is performed by measuring a deviation of a focus drive signal or a track drive signal when the disk is rotated at a certain number of rotations. . 4. The optical disk device according to claim 1, wherein the booster changes the supply voltage stepwise by the controller. 5. The optical disk device according to claim 1, wherein the booster linearly varies a supply voltage according to a result of the deviation measurement by the controller.