JP2004145942A - Disk unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disk unit which can drive even a disk other than a 8 cm disk or a 12 cm disk at high speed. <P>SOLUTION: A system controller 36 of the disk unit discriminates the kind of the optical disk 10 on the basis of the rotation speed after the lapse of specified time from the start of the drive and on the basis of a FG signal 38 from a motor 12. The disk meeting the standard is driven at a maximum rotation speed of the unit, and for the disk not meeting the standard, the rotation speed is adjusted in accordance with the degree of the mass eccentricity of the disk. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a disk device, and more particularly to a rotational speed control of a disk device for driving various disks.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a disk device that reproduces or records information by driving a recording medium such as an optical disk, the size of the disk is determined based on physical information or the like recorded in advance on the disk, and the rotational speed is determined in accordance with the determined size. Techniques for limiting the speed are known. That is, the size information of the disk is read from the wobble signal of the disk, and the disk is driven at the maximum double speed when the mounted disk is a 12 cm disk, and at the quadruple speed when the mounted disk is an 8 cm disk. In the case of a disk, the disk is driven at double speed.
[0003]
[Patent Document 1]
JP-A-2002-117613 (FIG. 10)
[0004]
[Problems to be solved by the invention]
As described above, by adjusting the rotation speed according to the disk size, it is possible to reliably perform recording or reproduction on a plurality of types of disks. However, recently, a variety of discs have emerged, and it is desired to perform recording and reproduction on these discs as fast as possible. Rather than limiting the rotational speed, it is desired to drive at the maximum speed at which recording and reproduction can be performed reliably.
[0005]
The present invention has been made in view of the above-mentioned problems of the related art, and an object of the present invention is to provide a device that can be driven at high speed even when a disc other than a standard disc such as a 12 cm disc or an 8 cm disc is loaded. is there.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a drive unit for rotating a disk, a first determination unit for determining whether the disk is within a predetermined standard, and a first determination unit for determining whether the disk is not within a predetermined standard. Second determining means for determining whether the amount of eccentricity is within a predetermined allowable value, and controlling the driving means to drive at a first rotational speed when the disk is within a predetermined standard; Control means for controlling the disk to be driven at a second rotational speed lower than the first rotational speed when the disk is not within a predetermined standard and the amount of eccentricity is not within a predetermined allowable value. It is characterized by having. Even if the disc does not conform to the standard, the speed is not limited uniformly, but also the amount of eccentricity of the disk is evaluated, and if the amount of eccentricity is not within the allowable value, the speed is limited and high-speed driving is possible. Become. Note that a standard disc means that the size and thickness of the disc are within the standard.
[0007]
The control means, when the disc is not within a predetermined standard and the amount of eccentricity is within a predetermined allowable value, sets a third rotation speed between the first rotation speed and the second rotation speed. It is preferable to control to drive at a rotation speed. This enables high-speed driving even for a nonstandard disc.
[0008]
Further, the control means may control the disk to be driven at the first rotation speed when the disc is not within a predetermined standard and the amount of eccentricity is within a predetermined allowable value.
[0009]
Also, the control means may control the rotation speed between the first rotation speed and the second rotation speed when the disk is not within a predetermined standard and the amount of eccentricity is within a predetermined allowable value. It is also preferable to perform control so as to drive at a rotation speed according to the amount of eccentricity. Specifically, when the amount of eccentricity is small, driving is performed at a high rotation speed, and as the amount of eccentricity increases, driving is performed at a lower rotation speed.
[0010]
Further, the second determination means can make a determination based on a tracking error signal obtained when the disk is driven at a predetermined rotation speed.
[0011]
Further, the first determination means can make the determination based on the moment of inertia of the disk, and can make the determination based on a ratio of the moment of inertia to a reference value of the disk. Also, the determination can be made based on the rotation speed of the disk after a predetermined time from the start of driving by the driving unit.
[0012]
In the present invention, the “disc” is not limited to a disk-shaped disk, but includes a disk-shaped disk such as a heart-shaped or character-shaped disk.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking an optical disk device as an example.
[0014]
FIG. 1 shows a configuration block diagram of the present embodiment. The optical disk 10 is driven to rotate by a motor (spindle motor) 12. The motor 12 is controlled by a disk motor servo circuit 14, and the disk motor servo circuit 14 servo-controls the motor 12 to a desired rotation speed according to a control command from a system controller 36. For this reason, an FG signal 38 indicating a rotation speed generated by a Hall element or the like built in the motor 12 is supplied to the system controller 36. The rotation control of the motor 12 will be described in more detail.
[0015]
The pickup (PU) 16 includes a laser diode (LD) that is arranged to face the optical disc 10 and irradiates the surface of the optical disc 10 with laser light. The laser diode is driven by the light emission control circuit 22, and the laser light irradiation from the light emission control circuit 22 is controlled by the system controller 36. Further, the pickup 16 has a photodetector that converts the laser light reflected from the optical disk 10 into an electric signal, and outputs a reproduced signal to the amplification and operation circuit 24. The pickup 16 is driven in a radial direction or a track width direction of the optical disk 10 by a sled motor 18, and the sled motor 18 is controlled by a sled motor control circuit 20. When reproducing data recorded in a certain area of the optical disk 10, the sled motor control circuit 20 drives the sled motor 18 in accordance with a command from the system controller 36, and drives the pickup 16 in the radial direction to reproduce the data.
[0016]
The amplification and operation circuit 24 amplifies the reproduction signal, adds the signals to each other, and outputs the resultant signal to the reproduction signal processing circuit 30. The amplification and operation circuit 24 calculates a difference between the signals to generate a focus error signal and a tracking error signal, and respectively performs focus servo control. The signals are output to the circuit 26 and the tracking servo circuit 28. For example, in the case of a four-divided photodetector, a tracking error signal is generated from a difference between detectors divided in the radial direction, and a focus error signal is generated from a difference between diagonal sums of the four-divided photodetectors. The focus servo circuit 26 and the tracking servo circuit 28 perform servo control of the pickup 16 in the focus direction and the track width direction using the focus error signal and the tracking error signal, respectively, and maintain the on-focus state and the on-track state.
[0017]
The reproduction signal processing circuit 30 binarizes and demodulates the reproduction signal, and outputs it to a host device 34 such as a personal computer via the interface 32. When a wobble signal is formed on the optical disk 10 in advance, the wobble signal is supplied to the disk motor servo circuit 14 to perform servo control based on the wobble signal.
[0018]
In such a configuration, when the optical disk 10 is mounted, the system controller 36 outputs a drive command to the disk motor servo circuit 14, and the disk motor servo circuit 14 drives the motor 12 at a constant voltage. The rotation speed ω (T) after a time T from driving the motor 12 at a constant voltage is:
(Equation 1)
ω (T) = K · (1−exp [−T / τm])
τm = Ra ・ J / Kt / Ke (1)
It is. Here, K is a constant, Ra is the electric resistance of the motor 12, J is the moment of inertia, and Kt is the torque constant. Accordingly, as the inertia is smaller and the mechanical time constant τm is smaller, the rate of change of the rotation speed is larger, and the target rotation speed is reached sooner.
[0019]
FIG. 2 shows a temporal change of the rotation speed when the motor 12 is driven at a constant voltage, using various optical disks having different moments of inertia as parameters. In the figure, the horizontal axis is the elapsed time from the start of driving at a constant voltage, and the vertical axis is the rotation speed. There are four cases, ie, no disk, 8 cm disk, 12 cm disk, and non-standard disk having a special shape, all of which reach the maximum rotation speed ωmax after sufficient time has passed. When the rotational speeds are compared at a predetermined time T after the start of the rotational drive, the rotational speed changes according to the magnitude of the moment of inertia. Assuming that the magnitude of the moment of inertia is no disk <8 cm disk <special shape disk <12 cm disk, the rotational speed is no disk> 8 cm disk> special shape disk> 12 cm disk. Specifically, the threshold is ωth1 or less for a 12 cm disk, ωth2 (ωth1 <ωth2) or less for an 8 cm disk, and ωth2 or more when no disk is present. Is between the 8 cm disk and the 12 cm disk.
[0020]
Therefore, by monitoring the rotation speed after a predetermined time from the start of driving, it is possible to distinguish the presence / absence of a disk, and if the disk is present, whether it is an 8 cm disk, a 12 cm disk, or a nonstandard disk. is there. The system controller 36 determines a disk based on such a difference in rotation speed. Then, the system controller 36 calculates the inertia moment ratio of the mounted disk based on the inertia moment of the 12 cm disk, and based on this ratio, determines whether the disk is a standard disk such as a 12 cm disk or an 8 cm disk, or a standard disk. It is determined whether the disk is an external disk, and the rotation speed of the motor 12 is switched according to the determination result. Specifically, if the disc is a standard disc, it is driven at the maximum rotational speed (for example, 24 times speed) of the apparatus, and if it is a non-standard disc, it is driven at a lower rotational speed (for example, 2 times speed) than the maximum rotational speed. I do.
[0021]
On the other hand, even if the disc is a non-standard disc, for example, there may be a disc that is not a heart shape or a specific character shape but a substantially circular disc with almost no eccentricity. As such a disc, for example, a DVD disc having a disc thickness of 0.6 mm, which is half of the standard 1.2 mm, without performing double-sided bonding is exemplified. Such a disc can be driven at a higher speed than other discs even if it is out of specification (tracking servo and focus servo function effectively) in many cases. Therefore, even if the disc is determined to be out of specification, the system controller 36 further determines whether or not the amount of eccentricity of the disc is within the allowable range. I do. That is, the rotation speed control by the system controller 36 is divided into the following cases.
[0022]
(1) Maximum rotation speed (for example, 24 times speed) in the case of a standard disc
(2) Intermediate rotation speed (for example, quadruple speed) of a non-standard disc whose eccentricity is within the allowable range
(3) A non-standard disc whose eccentricity is out of the allowable range.
It should be noted that even if the disc is a nonstandard disc, the rotation speed is not switched to the minimum rotation speed, but the rotation speed is further switched according to the value of the eccentricity.
[0023]
If the disc is a non-standard disc and the eccentricity is within the allowable range, it is possible to set the maximum rotation speed in the same manner as the disc in the standard, instead of setting it between the maximum rotation speed and the minimum rotation speed. It is also preferable to set the maximum rotation speed and reduce the rotation speed stepwise from the maximum rotation speed when the tracking servo or the focus servo does not function.
[0024]
Whether or not the eccentricity of the disk is within a predetermined allowable range can be determined based on the amplitude of the tracking error signal. That is, the tracking error signal generated by the amplification and operation circuit 24 is supplied to the tracking servo circuit 28 and also to the system controller 36. The system controller 36 determines the amplitude (average amplitude) of the tracking error signal in advance. The disk drive is compared with a predetermined threshold value stored in the memory. If the threshold value is exceeded, it is determined that the eccentricity is out of the allowable range, and the disc motor servo circuit 14 is instructed.
[0025]
3 and 4 show flowcharts of the entire processing according to the present embodiment. First, in FIG. 3, a command voltage is output from the system controller 36 (S101), and a constant drive voltage is output from the disk motor servo circuit 14 to the motor 12 (S102). After the driving voltage is output, the system controller 36 waits for a certain time T (S103). After the certain time T has elapsed, the system controller 36 inputs the FG signal 38 output from the motor 12, and measures the rotation speed ω of the motor 12 from the FG signal. (S104). The FG signal outputs a fixed number of pulses (for example, 8 pulses) per one rotation of the motor 12. The system controller 36 can obtain the frequency by counting the number of pulses of the FG signal within a predetermined time. The rotation frequency of the motor 12, that is, the rotation speed ω can be measured by dividing the obtained frequency by the number of pulses per rotation (for example, 8 pulses).
[0026]
After measuring the rotation speed ω after a certain time T from the start of driving, the reference rotation speed ω0, that is, the speed ratio with the rotation speed obtained in the certain time T when the 12 cm disk as the reference disk is mounted is calculated. (S105). The reference rotation speed ω0 may be stored in advance in a memory of the system controller 36, for example. After calculating the rotation speed ratio, an inertia moment (inertia) ratio, that is, a ratio with respect to the inertia moment of a 12 cm disk, which is a reference of the mounted disk, is calculated from the speed ratio (S106). Since the rotational speed and the moment of inertia have a 1: 1 relationship as can be seen from the above equation, the calculation of the moment of inertia ratio based on the speed ratio is easy. By calculating the moment of inertia ratio, the loaded disk can be determined (S107). For example, if the moment of inertia ratio (moment of inertia of mounted disc / moment of inertia of 12 cm disc) is extremely small, the disc has not been mounted yet, and if 1 the standard disc of 12 cm, for example, 0.2, Is determined to be an 8 cm standard disc. The determination result is stored in the memory of the system controller 36.
[0027]
Next, as shown in FIG. 4, the system controller 36 determines whether a disk is mounted (S108). If it is determined in S107 that there is no disk mounted, the determination in this process is YES, and the system controller 36 stops the disk motor servo circuit 14 (S110). On the other hand, if a disk is mounted, it is determined whether the mounted disk is a standard disk (S109). In the case of a standard disc, the system controller 36 sets the rotation speed, that is, the recording / reproduction speed, to the maximum rotation speed of the apparatus (S111), and further sets the gain of the disk motor servo circuit 14 and the transfer rate of the recording / reproduction circuit to the maximum speed. Is set (S112).
[0028]
On the other hand, if the disk is not a standard disk, the system controller 36 next determines whether the amount of eccentricity of the disk is equal to or less than the threshold value and is within an allowable range (S113). If the eccentricity of the mounting disk is within the allowable range, the system controller 36 sets an intermediate rotation speed between the maximum rotation speed and the minimum rotation speed instead of setting the rotation speed to the minimum rotation speed even if the eccentricity is out of specification ( S114). Thereafter, parameters such as a gain and a transfer rate are set for the intermediate rotation speed (S112). As described above, it is also possible to set the maximum rotation speed instead of the intermediate rotation speed. Alternatively, the rotation speed can be made variable according to the difference from the threshold value, that is, according to the degree of the eccentricity. When the eccentricity is small, the rotation speed is set near the maximum rotation speed, and when the eccentricity is large and close to the threshold value, the rotation speed is set near the minimum rotation speed. FIG. 5 shows the relationship between the degree of eccentricity and the rotation speed of a nonstandard disc. If the amount of eccentricity is equal to or less than the threshold value, the system controller 36 sets the rotation speed so as to have a negative correlation with the amount of eccentricity (to increase as the amount of eccentricity is smaller).
[0029]
On the other hand, if NO in S113, that is, if the amount of eccentricity of the non-standard disc exceeds the threshold value, the minimum rotation speed of the apparatus is set (S115), and the parameter is set for the minimum speed (S112).
[0030]
As described above, in the present embodiment, the rotation speed (recording / reproduction speed) is not limited uniformly even for a non-standard disc, but the speed is limited according to the degree of eccentricity. However, high-speed driving can be performed on a disk having a small eccentricity.
[0031]
In the present embodiment, the inertia moment ratio is calculated from the rotation speed ratio during the fixed time T, but the disc can be immediately discriminated from the rotation speed ratio.
[0032]
Further, the disc may be determined from the absolute value of the rotation speed during the fixed time T instead of the rotation speed ratio. That is, the rotation speed value of the standard disk after a predetermined time T is stored in the memory of the system controller 36 in advance, and the detected rotation speed value is compared with the value stored in the memory to determine the disk. Is also good.
[0033]
In this embodiment, a 12 cm optical disk is used as a reference disk. However, servo parameters can be adjusted by calculating an inertia moment ratio and a rotation speed ratio based on an 8 cm optical disk. Can be selected arbitrarily.
[0034]
Further, in the present embodiment, the amount of eccentricity is evaluated based on the tracking error signal. However, the amount of eccentricity may be detected by another method, and the amount of eccentricity is measured in advance and recorded in a predetermined area of the disk. In addition, it is also possible to read out this data after loading the disk and supply it to the system controller 36, and the system controller 36 evaluates the amount of eccentricity. Whether or not the disc is a standard disc may be determined by recording data about the size and thickness in a predetermined area of the disc in advance and reading this data.
[0035]
【The invention's effect】
As described above, according to the present invention, even if an arbitrary disk is mounted, the disk is driven at an optimum rotation speed for each disk, so that high-speed driving is possible.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an embodiment.
FIG. 2 is a graph showing a relationship between an elapsed time from the start of driving and a rotation speed.
FIG. 3 is an overall processing flowchart (part 1) of the embodiment;
FIG. 4 is an overall processing flowchart (part 2) of the embodiment;
FIG. 5 is a graph showing the relationship between the amount of eccentricity and the rotational speed of the nonstandard disc according to the embodiment.
[Explanation of symbols]
10 optical disk, 12 motor (spindle motor), 14 disk motor servo circuit, 36 system controller.

Claims (8)

Driving means for rotating and driving the disk;
First determining means for determining whether the disk is within a predetermined standard;
A second determination unit that determines whether the amount of eccentricity is within a predetermined allowable value when the disk is not within a predetermined standard,
When the disk is within a predetermined standard, the drive unit is controlled to be driven at a first rotational speed, and when the disk is not within a predetermined standard, the amount of eccentricity is within a predetermined allowable value. Control means for controlling to drive at a second rotation speed lower than the first rotation speed if not.
A disk device comprising: The device of claim 1,
The control means, when the disk is not within a predetermined standard and the amount of eccentricity is within a predetermined allowable value, sets a third rotation speed between the first rotation speed and the second rotation speed. A disk device which is controlled so as to be driven at a rotational speed. The device of claim 1,
The control means controls to drive at the first rotational speed when the disc is not within a predetermined standard and the amount of eccentricity is within a predetermined allowable value. Disk device. The device of claim 1,
The control means may control the rotation speed between the first rotation speed and the second rotation speed when the disc is not within a predetermined standard and the amount of eccentricity is within a predetermined allowable value. A disk drive device for controlling the drive so as to drive at a rotation speed according to the amount of eccentricity. The device of claim 1,
The disk device according to claim 2, wherein the second determination unit makes a determination based on a tracking error signal obtained when the disk is driven at a predetermined rotation speed. The device of claim 1,
The disk device according to claim 1, wherein the first determination unit makes a determination based on a moment of inertia of the disk. The device of claim 1,
The disk device according to claim 1, wherein the first determination unit makes a determination based on a ratio of a moment of inertia to a reference value of the disk. The device of claim 1,
The disk device according to claim 1, wherein the first determination unit makes a determination based on a rotation speed of the disk after a predetermined time after the drive unit starts driving.

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