JPH06187724A - Clv circuit of optical disk device - Google Patents

Abstract

PURPOSE:To search for the target position of signal recording tracks in a short period of time by controlling the number of revolutions of a spindle motor in accordance with the difference between the number of spindle motor revolutions of a search originator and a search destination. CONSTITUTION:During a start of a spindle motor 8, a microcomputer 9 sends an instruction to a PLL circuit 3 so as to make the pulse width of phase difference signals (MDP) to a prescribed period H and starts the rotation of the motor 8. Moreover, in accordance with the program written in a ROM 11 and the signals from a key input device 10, a RAM 12 is used for the operations so as to control the entire device and performs a mode switching of the circuit 3. By supplying a current to the spindle motor for the amount of current-time product which is equivalent to the angular momentum change which corresponds to the difference between the number of revolutions of the motor 8 of the search originator and the search destination, the speed of the spindle motor is increased or decreased so that the speed of the track being seeked is kept at a target speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk drive CL.
CL of an optical disk device related to the V circuit, and particularly for speeding up the rotation speed of the spindle motor after track search
Regarding the V circuit.

[0002]

2. Description of the Related Art In a recordable optical disc, a pregroove having a waveform for guiding a laser spot is engraved, and CLV (constant linear velocity) control is performed by keeping a frequency of a wobble signal obtained from the waveform constant.

CLV of such a conventional optical disk device
An example of the circuit is shown in FIG. TE shown in the figure is a tracking error signal, which is obtained by receiving the reflected light from the optical disc by the split light receiving elements and differentially amplifying the output. The tracking error signal (T
From E), a wobble signal having a center frequency of 22.05 kHz designed by the bandpass filter 2 is extracted.

The wobble signal is compared in phase and frequency by the PLL circuit 3 with the reference frequency signal generated by the timing generation circuit 4. The address decoder 5 demodulates the disk position information using the clock output from the PLL circuit and outputs it to the microcomputer 9.

The operation mode of the PLL circuit 3 is controlled by the microcomputer 9. In the CLV mode, a pulse width phase difference signal (MDP) and a pulse width speed difference signal (MDS) are output to the CLV servo circuit 6. . The MON signal output from the PLL circuit 3 to the CLV servo circuit 6 is a signal for instructing rotation or stop (rotation by inertia) of the motor by H and L, and is set to H in the CLV mode.

The CLV servo circuit 6 basically has a low-pass filter function, converts the pulse width signals of MDS and MDP into analog signals and adds them to generate a rotation control signal for the spindle motor 8 to drive the motor. Output to the amplifier 7. The motor drive amplifier 7 supplies a current to the spindle motor 8 by amplifying the input signal.

Note that M input to the CLV servo circuit 6
When the H pulse width in one DP cycle exceeds the reference value, a forward rotation current is supplied to the spindle motor 8, and when the H pulse width in one MDP cycle is less than the reference value, a reverse rotation current is supplied to the spindle motor 8. To be done.

When the spindle motor 8 is activated, the microcomputer 9 instructs the PLL circuit 3 to perform MDP.
Can be started for a predetermined period H to start the rotation of the spindle motor 8.

The microcomputer 9 operates according to a program written in the ROM 11 and a signal from the key input device 10 while using the RAM 12 for work, and controls the entire device. However, as described above, the PLL circuit 3 operates. Switch the mode.

[0010]

According to the CLV circuit of the above-mentioned conventional optical disk device, when the target position of the signal recording track is searched, the traverse signal generated by the track jump has a frequency close to that of the wobble signal. It is difficult to separate and demodulate the wobble signal, and the spindle servo cannot be applied.

Therefore, the spindle servo may be largely deviated during the track jump. In that case, it takes time until the rotation speed of the spindle motor is pulled in and the servo is locked, and the track position information is read to obtain the target. There was a problem that it took a long time to confirm the position and the search was delayed.

The present invention has been made in view of the above points, and an object thereof is to provide a CLV circuit of an optical disk device capable of searching a target position of a signal recording track in a short time. It is in.

[0013]

A CLV circuit of an optical disk apparatus according to the present invention supplies a current to a spindle motor so as to keep a frequency of a wobble signal obtained from a waveform of a pre-groove of the optical disk constant, thereby recording a signal recording track. CL of the optical disk device that controls the linear velocity of the
In the V circuit, at the time of track search, after the current is supplied to the spindle motor by the current-time product corresponding to the angular momentum change corresponding to the difference between the search-source spindle motor rotation speed and the search-destination spindle motor rotation speed, until the search is completed. It is configured to supply a current corresponding to the number of revolutions of the spindle motor to be searched.

[0014]

The number of rotations of the spindle motor that makes the speed of the track a constant target speed in a predetermined information recording track is determined depending on the type of the optical disc. When the search source track and the search destination track are determined, the spindle motor speed is increased. Alternatively, the difference in the number of rotations for deceleration is obtained.

The angular momentum is the product of the number of revolutions for accelerating or decelerating the spindle motor and the moment of inertia of the disk, the motor and the turntable, and this angular momentum change is given by the current supplied to the spindle motor.

The change in the angular momentum is given by the product of the torque for increasing / decreasing and the time for applying it. Further, the torque generated by the electromagnetic force of the motor is proportional to the electric current, and the torque is the sum of the torque for acceleration / deceleration and the friction resistance torque.

According to the CLV circuit of the optical disk device of the present invention, at the time of track search, the current-time product corresponding to the change in the angular momentum corresponding to the difference between the rotational speed of the spindle motor of the search source and the rotational speed of the spindle motor of the search destination. By only supplying current to the spindle motor, the spindle motor is accelerated or decelerated so that the speed of the track to be searched becomes a constant target speed. After the spindle motor has been rotated at the substantially target number of revolutions in this way, the spindle motor is rotated at a substantially constant number of revolutions by supplying a current necessary to maintain the number of revolutions.

When the rotation of the spindle motor is controlled in this way, the number of rotations after a predetermined track jump does not deviate significantly from the target value, and the rotation of the spindle motor is quickly pulled in to shorten the search time.

[0019]

Embodiment C of an optical disk device according to an embodiment of the present invention
The LV circuit will be described with reference to the drawings. The hardware configuration of the CLV circuit of the embodiment is similar to that shown in FIG.
In the embodiment, the operation of accelerating and decelerating the spindle motor to a substantially target rotational speed is performed by the software of the microcomputer 9 during the track search.

FIG. 1 shows the operation of the microcomputer 9 as a function realizing means.

The microcomputer 9 has a current position reading means for controlling the spindle motor at the time of track search, and has six function realizing means shown in the following figures.
The operation of these function realizing means is executed by a program.

The current position reading means holds the information on the type of the disc by reading the disc information from the address decoder 5 when the disc is mounted, but obtains the information on the current track position from the address decoder 5 at the time of track search.

The search position reading means is the key input device 1
Upon receiving a command from 0, the track position of the search destination is calculated. When an operation accompanied by a track search is instructed from the key input device 10, track position information of the search destination is sent from the search position reading means to the search direction / search distance determining means. Further, the information about the type of the disc and the information about the current position are sent from the current position reading means to the search direction and search distance determining means.

The search direction / search distance determination means calculates the difference in angular momentum corresponding to the difference between the spindle motor rotation speed of the search source and the spindle motor rotation speed of the search destination from these information, and sets the information as the pulse length. Send to the means. Also, the track position information of the search destination is sent from the search position reading means to the CAV pulse setting means.

The pulse length setting means is an MDP H output by the PLL 3 in order to accelerate or decelerate the spindle motor.
Or the period of L, and the CAV pulse setting means outputs M from one cycle output from the PLL 3 in order to maintain the rotation speed after the spindle motor is accelerated or decelerated.
Find the time when DP is H.

That is, the pulse length setting means reads the MDP H from the table in the ROM 11 based on the information on the difference in the angular momentum.
, Or L, and sends the information to the command generating means. Further, the CAV pulse setting means obtains the H period or L period of the MDP from the table of the ROM 11 based on the spindle motor rotation speed information to be set and sends the information to the command generating means.

The command generating means uses the information to generate the PL
The L3 is instructed to set the MDP to H or L for a predetermined period to accelerate or decelerate the spindle motor, and thereafter to output a pulse of MDP having a predetermined width so as to maintain the rotation speed.

FIG. 2 shows the waveform of the MDP and the change in the spindle motor speed when the track is searched toward the inner circumference side. Before the search operation, CLV operation is performed and M
ON is H and MDP is controlled to three values of H, L and Z (high impedance). When you enter the search,
First, the spindle motor is accelerated for the acceleration period calculated by the pulse length setting means.

During the acceleration period, MDP becomes H, that is, a kick pulse is output and the spindle motor is accelerated.
After that, MDP and MON are controlled to H and L in accordance with the H and L periods set by the CAV pulse setting means, and the rotation speed of the spindle motor is kept constant.

FIG. 2 shows a case where the track is searched to the inner circumference side to accelerate the spindle motor, but when the track is searched to the outer circumference side and the spindle motor is decelerated, MDP becomes L during the deceleration period. , I.e. the brake pulse is output and the spindle motor is decelerated, then
The rotation speed of the spindle motor is kept constant as in the search on the inner circumference side.

In this way, a track jump is performed while the spindle motor is controlled, and the spindle motor is CLV controlled at that position to check the track position information. If the track is not at the target position, the above operation is repeated.

FIG. 3 shows a procedure for the operation of the spindle motor rotation control. In step S1, the size of the disc is determined from the information read when the disc is mounted. Next, in step S2, the track position information of the search destination and the current track position information are obtained, and the process proceeds to step S3.

In step S3, a kick pulse or a brake pulse corresponding to the track position information of the search destination and the current track position information is applied to the CLV servo circuit 6 to accelerate or decelerate the spindle motor.

Next, in step S4, a signal having a pulse width for maintaining the rotation speed corresponding to the track position of the search destination is added to the CLV servo circuit 6 and the completion of the track jump is waited.

When the planned number of track jumps are completed,
In step S5, the PLL 3 is set to the CLV mode, the linear velocity is controlled to be constant, the address information is read out, and the process proceeds to step S6. In step S6, it is determined whether or not the read address information is for the target position. If the read address information is the target position, the search operation is terminated, and if it is not the target position, steps S2 and thereafter are repeated.

[0036]

As described above, according to the CLV circuit of the optical disk device of the present invention, at the time of track search, the angular momentum corresponding to the difference between the spindle motor rotation speed of the search source and the spindle motor rotation speed of the search destination is firstly determined. By supplying a current to the spindle motor by a current-time product corresponding to the change, the spindle motor is accelerated or decelerated so that the speed of the track to be searched becomes a constant target speed.
After the spindle motor has been rotated at the substantially target number of revolutions in this way, the spindle motor is rotated at a substantially constant number of revolutions by supplying a current necessary to maintain the number of revolutions.

By controlling the rotation of the spindle motor in this way, the number of rotations after a predetermined track jump does not deviate significantly from the target value, and the rotation of the spindle motor is quickly pulled in to shorten the search time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a function realizing means in an embodiment of the present invention.

FIG. 2 is a time chart showing the operation in the same embodiment.

FIG. 3 is a flowchart showing an operation in the same embodiment.

FIG. 4 is a block diagram showing an example of a CLV circuit of a conventional optical disc device.

[Explanation of symbols]

 1 Amplifier 2 Band Pass Filter 3 PLL Circuit 4 Timing Generation Circuit 5 Address Decoder 6 CLV Servo Circuit 7 Motor Drive Amplifier 8 Spindle Motor 9 Microcomputer 10 Key Input Device 11 ROM 12 RAM

Claims (1)

[Claims] 1. A CLV circuit of an optical disk device for controlling a linear velocity of a signal recording track to be constant by supplying a current to a spindle motor so as to make a frequency of a wobble signal obtained from a waveform of a pre-groove of the optical disk constant. , During track search, after supplying current to the spindle motor for the current-time product corresponding to the angular momentum change corresponding to the difference between the spindle motor rotation speed of the search source and the spindle motor rotation speed of the search destination, A CLV circuit of an optical disk device configured to supply a current corresponding to the spindle motor rotation speed.