JP2000011395A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk device shortening a time required for moving an optical head to a target track. SOLUTION: The optical disk device is provided with a rotary drive mechanism loading an optical disk and rotating it, the optical head, an optical head moving mechanism provided with a thread motor moving the optical head in the radial direction and a control means. When the optical head is moved to the target track, an absolute value (number of target transition tracks of optical head) Nc of Tc-To is obtained (104), and when Nc<=8000, a head transfer pulse voltage of +5 V, 25 ms (109), a brake pulse voltage of -5 V, 15 ms (113) and the brake pulse of -5 V, 5 ms (115) are set, and when 1500<=Nc<8000, the head transfer pulse voltage of +5 V, 20 ms (111) and the brake pulse voltage of -5 V, 5 ms (115) are set, and when 120<=Nc<1500, the head transfer pulse voltage of +5 V, 5 ms (110) is set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an optical disk device.

[0002]

2. Description of the Related Art There is known an optical disk device for reproducing or recording / reproducing a read-only optical disk such as a CD-ROM or a recordable / reproducible optical disk such as a CD-R or CD-RW.

[0003] This optical disk device includes a rotation drive mechanism for mounting and rotating an optical disk, an optical head (optical pickup) capable of moving in a radial direction with respect to the mounted optical disk, and a method for moving the optical head in a radial direction. An optical head moving mechanism having a sled motor for moving.

The optical head is provided with an optical head body (optical pickup base) having a laser diode and a divided photodiode, and a suspension spring so that the optical head body can be moved in the radial direction and the rotation axis direction of the optical disk, respectively. It is composed of a supported objective lens and an actuator for moving the objective lens in the rotation axis direction and the radial direction.

In such an optical disk device, the optical head is moved to a target track (target address), and information (data) is recorded on the optical disk while focusing control and tracking control are performed on the target track. (Reproduction) of the information from.

When moving the optical head to the target track, first, the sled motor is driven to move the entire optical head to the vicinity of the target track (coarse seek is performed).

That is, an acceleration pulse voltage is applied to the sled motor to move the optical head in the radial direction. At that time, the number of pulses of the tracking error signal is counted, and thereby, the track that the optical head has passed (traversed). Find the number of When the number of tracks (count value) reaches a predetermined value, the counting is stopped, a deceleration pulse voltage is applied to the sled motor, and braking of the sled motor is started.
Thus, the optical head stops after a predetermined time.

Next, the address where the optical head is located is read, and the coarse seek is repeated until the number of tracks from the track where the optical head is located to the target track is equal to or less than a predetermined value.

When the number of tracks from the track where the optical head is located to the target track becomes equal to or less than a predetermined value, the actuator is driven to move the objective lens in the radial direction. When the optical head is driven to follow the objective lens, the optical head is moved to a target track (performs a precise seek).

However, in the above-mentioned conventional optical disk apparatus, coarse seek accuracy is poor. Therefore, when the optical head is moved to the target track, coarse seek may be performed many times. There is a disadvantage that it takes a long time to move to the (target address) (access time is long).

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical disk apparatus capable of shortening a time (access time) required for moving an optical head to a target track (target address).

[0012]

This and other objects are achieved by the present invention which is defined below as (1) to (10).

(1) A rotation drive mechanism for mounting and rotating an optical disk, an optical head movably mounted in a radial direction of the optical disk, and a motor, wherein the motor is disposed in a radial direction of the optical disk with respect to the optical disk. An optical head moving mechanism for moving an optical head, the optical disk device recording and / or reproducing the optical disk, wherein the optical head passes when the optical head is moved to a target position on the optical disk. An optical disc device comprising a setting unit for setting a drive pattern of the motor according to the number of tracks.

(2) The optical disk device according to (1), wherein a driving pattern of the motor is set by changing a braking condition of the motor.

(3) The optical disk device according to (1) or (2), wherein the drive pattern of the motor is set by changing a value of a drive voltage and / or an application time of the motor.

(4) When the motor is braked when the optical head is moved to a target position on the optical disk, the braking operation can be performed a plurality of times. The optical disk device according to any one of (3).

[0017] (5) wherein when the optical head and the number of tracks through which the optical head is the reference value N ₁ or more when moving to a target position on the optical disc, the setting means, the braking of the motor The optical disc device according to (4), wherein the drive pattern of the motor is set so that the braking operation is performed a plurality of times.

(6) When the braking operation is performed a plurality of times,
The optical disc device according to the above (4) or (5), which is configured to perform these operations intermittently.

(7) When the optical head is moved to a target position on the optical disk, there is provided a remaining track number detecting means for detecting passage of a track of the optical head and obtaining a remaining track number to the target position. The optical disk according to any one of (1) to (6), wherein the motor is started to brake when the number of remaining tracks obtained by the remaining track number detecting means reaches a predetermined value. apparatus.

(8) The remaining track number detecting means includes:
The optical disc apparatus according to (7), wherein even when braking the motor, the optical head detects passage of the track of the optical head to determine the number of remaining tracks to the target position.

(9) When the optical head is moved to a target position on the optical disk, there is provided a remaining track number detecting means for detecting passage of the track of the optical head and obtaining a remaining track number to the target position. When the braking operation is performed a plurality of times, when the number of remaining tracks obtained by the remaining track number detecting means reaches a first value, a first braking operation in braking the motor is started, and the remaining track is started. When the number of remaining tracks obtained by the number detecting means reaches a second value smaller than the first value,
The optical disc device according to any one of (4) to (6), wherein a second braking operation in braking the motor is started.

(10) The absolute value and / or application time of the drive voltage of the motor in the first braking operation is
(9) which is larger than that in the second braking operation.
An optical disk device according to claim 1.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical disk drive according to the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment (main part) of an optical disk device of the present invention, and FIG. 2 is a plan view showing an embodiment (with a casing removed) of the optical disk device of the present invention.

The optical disk device 1 shown in these figures is a CD-ROM drive device for reproducing an optical disk (CD-ROM) 2. A spiral track is formed on the optical disc 2.

The optical disk device 1 has a rotation drive mechanism for mounting and rotating the optical disk 2. The rotation drive mechanism mainly includes a spindle motor 11 for rotating the turntable, and a turntable 13 fixed to the rotation shaft 12 of the spindle motor 11 and on which the optical disc 2 is mounted.

The optical disk apparatus 1 moves in the radial direction of the optical disk 2 (radial direction of the turntable 13) with respect to the loaded optical disk 2 (turntable 13), that is, in the direction of arrow A in FIG. An optical head (optical pickup) 3 to be obtained, an optical head moving mechanism for moving the optical head 3 in the radial direction, a control means 9, a memory (RAM, ROM, E ² PROM, etc.) 10, and these are housed. And a casing (not shown). Hereinafter, the radial direction of the optical disk 2 is simply referred to as “radial direction”.

The optical head 3 has an optical head main body (optical pickup base) 31 having a laser diode (light source) 5 and a divided photodiode (light receiving section) 6, and an objective lens (condensing lens) 32. I have.

The objective lens 32 is supported by a suspension spring (not shown) provided on the optical head body 31.
With respect to the optical head body 31,
(The turntable 13) can be moved in the respective rotation axis directions. When the objective lens 32 deviates from its neutral position (middle point), the objective lens 32 is urged toward the neutral position by the restoring force of the suspension spring. Hereinafter, the direction of the rotation axis of the optical disc 2 will be simply referred to as “the direction of the rotation axis”.

The optical head 3 is an optical head body 3
1 has an actuator 4 for moving the objective lens 32 in each of the radial direction and the rotation axis direction.

The optical head body 31 is formed with three support portions (sliders) 311 that slide along the guide shaft 16 described later.

The optical head moving mechanism mainly includes a sled motor 7, a lead screw (worm gear) 81 fixed to the rotating shaft 8 of the sled motor 7, the reduction gear 14, the rack gear 15, and the optical head 3. It comprises a pair of guide shafts 16 for guiding, and the above-mentioned three support portions (sliders) 311.

The reduction gear 14 is composed of a worm wheel 141 meshing with the lead screw 81, and a pinion gear 142 fixed concentrically to the worm wheel 141 and having a smaller diameter than the worm wheel 141.

The rack gear 15 meshes with the pinion gear 142 and is fixed to the optical head main body 31.

As described above, the optical head 3 supports the pair of guide shafts 16, 16 with the support portions 31.
1 movably supported.

The thread motor 7 is driven, and its rotating shaft 8
When the lead screw 81 rotates in a predetermined direction,
The worm wheel 141 and the pinion gear 142 rotate in a predetermined direction, and the rack gear 15 and the pinion gear 142
Thus, the rotational movement of the pinion gear 142 is converted into a linear movement of the optical head 3, and the optical head 3 moves in a predetermined direction along the guide shaft 16.

When the rotation shaft 8 of the thread motor 7 and the lead screw 81 rotate in the opposite direction, the optical head 3 moves along the guide shaft 16 in the opposite direction.

The lead screw 81 (the rotating shaft 8 of the thread motor 7) has a disk 1 on which a magnet is installed.
7 is fixed. An MR element (detection means) 21 for detecting the rotation speed (the number of rotations) of the sled motor 7, which will be described later, is provided near the disk 17 (see FIG. 5).

The control means 9 is usually constituted by a microcomputer (CPU), and comprises an optical head 3 (actuator 4, laser diode 5, etc.), a memory 10, a thread motor 7, a spindle motor 11, and a speed control means (speed It controls the entire optical disc device 1 such as a control circuit).

The control means 9 controls the sled motor 7
The main functions of the setting means for setting the drive pattern and the remaining track number detecting means for obtaining the number of remaining tracks to the target position (target track) are achieved.

An external device (for example, a computer) is detachably connected to the optical disk device 1 via an interface controller (not shown).
And an external device.

Next, the operation and the circuit configuration of the optical disk device 1 will be described. The optical disk device 1 moves the optical head 3 to a target track (target address), and performs focus control, tracking control, sled control, rotation speed control (rotation speed control), and the like on this target track, while performing optical control from the optical disk 2. Reading (reproduction) of information (data) is performed.

At the time of reproduction, a laser beam is emitted from the laser diode 5 of the optical head 3 onto a predetermined track of the optical disk 2. This laser light is reflected by the optical disk 2, and the reflected light is received by the split photodiode 6 of the optical head 3.

A current corresponding to the amount of received light is output from the divided photodiode 6, and this current is supplied to an unillustrated I
-V amplifier (current-voltage conversion unit) is converted to voltage,
Output from the optical head 3.

Then, by adding or amplifying the voltage (detection signal) output from the optical head 3, H
An F (RF) signal is generated. This HF signal is an analog signal corresponding to pits and lands written on the optical disc 2.

This HF signal is binarized and EFM (Ei
ght to Fourteen Modulation), and is decoded (converted) into data (DATA signal) in a predetermined format.

The data is decoded into data of a predetermined format for communication (transmission) and transmitted to an external device (for example, a computer) via an interface control unit (not shown).

In the optical disk device 1, the optical head 3
When moving the (objective lens 32) to a target position on the optical disc 2, that is, a target track (target address),
Track jump control is performed. In this track jump control, the drive of the sled motor 7 and the drive of the actuator 4 are respectively controlled, and the optical head 3 is controlled by coarse seek, precision seek, or a combination thereof.
(Objective lens 32) is moved to the target track (target address).

Here, the optical head 3 (objective lens 32)
When the number of tracks (the number of tracks from the current track to the target track) through which the optical head 3 (objective lens 32) passes when the is moved from the current track (access start track) to the target track, that is, When the reference value (threshold) N ₀ is equal to or greater than a preset reference value (threshold value), coarse seek is performed. Hereinafter, the optical head 3 (objective lens 32) is moved to the current track (access start track).
The number of tracks through which the optical head 3 (objective lens 32) passes when moving from the target track to the target track is simply referred to as the "target passing track number".

If the objective lens 32 is not positioned on the target track at the time of completion of the coarse seek, then a precision seek is performed, and the objective lens 32 is moved to the target track by the precision seek. .

When the number of target passage tracks is relatively small, that is, when it is less than the reference value N ₀ , a precision seek is performed, and the objective lens 32 is moved to a target track by the precision seek.

In this embodiment, as shown in the flowchart (FIG. 10) described later, the reference value N ₀ is set to 120.
In the present invention, the reference value N ₀ is set to 1
Needless to say, it is not limited to 20.

Further, in the optical disc apparatus 1, the drive pattern of the sled motor 7 during the coarse seek, that is, the pattern (voltage) of the sled motor drive signal (voltage) for driving the sled motor 7 according to the target number of tracks to pass. Acceleration conditions, braking conditions, etc.) are set.

[0054] In this case, as when the target passes the number of tracks is a reference value (threshold) N ₁ or more is performed a plurality of times its braking action during the braking of the thread motor 7, drive pattern of the sled motor 7 Is set.

In this embodiment, as shown in a flowchart (FIG. 10) described later, the reference value N ₁ is set to 800
0 is set to, but the present invention, the reference value N ₁ is of course not limited to 8000.

Table 1 below shows a drive pattern of the sled motor 7 during the coarse seek in the present embodiment.

[0057]

[Table 1]

As shown in Table 1, when the number of target passage tracks is 8000 or more, the value of a head feed pulse signal (voltage) described later in the sled motor drive signal (voltage) is +5 V, and the application time (head feed Pulse width) is set to 25 ms, the first brake pulse voltage of the two brake pulse signals (voltages) described later in the sled motor drive signal (voltage) is -5 V, and the application time (brake pulse width) Is 15 ms, the value of the second brake pulse voltage is -5 V, and the application time (brake pulse width)
Is set to 5 ms.

When the target number of passing tracks is 1500 or more and less than 8000, the value of the head feed pulse voltage is set to +5 V, the application time is set to 20 ms, the value of the brake pulse voltage is set to -5 V, and the application time is set to Set to 5 ms.

When the number of target passage tracks is 120 or more and less than 1500, the value of the head feed pulse voltage is set to +5 V and the application time is set to 5 ms.

The operation when the optical head 3 is moved to the target track by performing a coarse seek and a precision seek will be described below.

FIGS. 3 and 4 are timing charts when the optical head 3 is moved to the target track by performing coarse seek and fine seek, respectively.

As shown in FIG. 3, the horizontal axis is the position of the optical head 3 on the optical disk 2, the access start position (coarse seek start position) is _Xo , the brake start position is _Xa , and the coarse seek end position (precision). Let _{Xb be} the seek start position) and _Xc be the destination position (access end position).

Then, X _{o to} X _a are set to the first control area, X
_{Let a to Xb} be the second control area. Incidentally, X _o to X _b is coarse seek operation region, the X _b to X _c is a precision seek operation region.

As described above, when the optical head 3 is moved to the target track, if the number of target passing tracks is equal to or _larger than the reference value N ₀ , coarse seek is performed.

As shown in FIG. 4, in the coarse seek, first,
A sled motor drive signal (voltage) is supplied to a sled driver (not shown) for driving the sled motor 7, that is, FIG.
The head feed pulse signal (voltage) shown in (a) is input, whereby the thread motor 7 is driven, and the optical head 3 starts moving toward the target track (accelerated).

In the first control area, when the moving speed (speed) of the optical head 3 converges to a substantially predetermined value, the speed control means (speed control circuit) described later uses
Speed control of the optical head 3 (rotation speed control of the sled motor 7) is performed so that the moving speed of the optical head 3 becomes constant.

FIG. 5 is a block diagram showing a configuration example of the speed control means (speed control circuit) of the optical disk device 1.

As shown in the figure, the MR element (detection means)
From 21, the rotation speed (the number of rotations) of the thread motor 7;
That is, an FG (Frequency Generator) signal corresponding to the moving speed of the optical head 3 (objective lens 32) is output and input to the moving speed signal generator 22.

In the moving speed signal generator 22, the frequency of the FG signal is converted into a voltage _Vte (F / V conversion).

[0071] Then, the difference voltage (differential) V _a between the voltage V _te and the reference voltage V _ref is the amplifier 23 is amplified by a predetermined amplification factor, and the voltage V _b after the amplification, FIGS. 4 (a) Is applied to the sled driver as a sled motor drive voltage. The sled motor drive voltage is shown in FIG.

[0072] Thus, (so as to reduce as much as possible) the difference voltage V _a between the voltage V _te and the reference voltage V _ref to be 0, the driving of the sled motor 7 is controlled, the sled motor 7 The rotation speed, that is, the moving speed of the optical head 3 becomes constant.

The signal (voltage) after the current-voltage conversion from the divided photodiode 6 of the optical head 3 is input to an error signal generation circuit (signal generation circuit) not shown. The error signal generation circuit generates a tracking error signal (TE) based on the signal from the divided photodiode 6.

The tracking error signal is output from the objective lens 32 in the radial direction of the optical disc 2 from the center of the track.
Is a signal indicating the magnitude and direction of the deviation (the deviation amount from the center of the track).

As shown in FIG. 7A, one waveform of the tracking error signal (analog signal) corresponds to one pitch of a track that has passed (crossed) the optical head 3 (objective lens 32).

FIG. 6 is a block diagram showing a configuration example of a circuit for generating a binary signal (track count signal) of the tracking error signal.

As shown in the figure, the tracking error signal (analog signal) generated by the error signal generation circuit is input to a limiter amplifier circuit (signal processing circuit) 41.

In the limiter amplifier circuit 41, the level of the tracking error signal is amplified at a predetermined amplification rate, and
Each of the peak side (peak side) and the valley side (bottom side) of the amplitude of the tracking error signal is limited so that the level of the tracking error signal does not exceed a predetermined threshold value.

As a result, the tracking error signal becomes 2
And a binary signal of the tracking error signal is obtained.

The amplification factor of the limiter amplifier circuit 41 is not particularly limited, but is preferably set to 20 dB or more.

The threshold value of the limiter amplifier circuit 41 is set to a value sufficiently larger than the noise component and sufficiently smaller than the amplitude of the tracking error signal.

The binarized signal from the limiter amplifier 41 is shaped by the waveform shaping circuit 42 as shown in FIG.

The binarized signal (track,
The count signal) is a signal corresponding to the number of tracks that the optical head 3 has passed (traversed), as described above. Therefore, the binarized signal is a signal of the track that the optical head 3 has passed (traversed). Used for counting.

Here, in an apparatus in which the limiter amplifier circuit 41 is not provided, as shown in FIG.
When the amplitude of the tracking error signal is small as shown in FIG. 7, the binarized signal (track count signal) corresponding to the waveform 51 is lost as shown in FIG. In some cases, it is not possible to accurately count the number of tracks that have passed through the limiter amplifying circuit 4 as described above.
Since the tracking error signal is binarized by 1, the waveform 51 can be reliably binarized as shown in FIG. 7B, and the number of tracks passed by the optical head 3 can be accurately counted. Can be.

In the optical disc device 1, the number of pulses of the binary signal is counted from the start of the coarse seek by a counter (not shown). That is, the passage of the track of the optical head 3 is detected, and the number of tracks is decremented by one each time the optical head 3 passes one track, whereby the number of tracks remaining until the target track is obtained.

When the count value (number of pulses) of the binarized signal reaches a predetermined value, that is, when the number of remaining tracks up to the target track has reached a predetermined value, as shown in FIGS. Then, a brake pulse signal (voltage) having a sign (positive or negative) opposite to the head feed pulse signal (voltage) is input to the sled driver as a sled motor drive voltage, whereby the braking of the sled motor 7 is started.

The operation of counting the number of pulses of the binarized signal, which has been performed since the start of the coarse seek, that is, detecting the passage of the track of the optical head 3 and obtaining the number of remaining tracks up to the target track is performed in this thread. The braking operation of the motor 7 is also continued.

In the timing chart shown in FIG. 4, although the application time for which the head feed pulse voltage is set ends and the number of remaining tracks to the target track reaches a predetermined value at the same time, If the number of remaining tracks up to the target track reaches a predetermined value before the set application time of the pulse voltage ends, when the remaining track number reaches the predetermined value, the application of the head feed pulse voltage is performed. Is stopped halfway, and a brake pulse voltage is applied.

The speed control of the optical head 3 is completed simultaneously with the end (stop) of the application of the head feed pulse voltage.

In the second control area, the moving speed of the optical head 3 decreases (the optical head 3 decelerates). Then, after a predetermined time, the optical head 3 stops near the target track.

Next, as shown in FIG. 4, a precision seek is performed. In this precision seek, only the actuator 4 is driven to move the objective lens 32 in the radial direction, or the actuator 4 is driven to move the objective lens 32 in the radial direction, and at the same time, the thread motor 7 is driven. The optical head main body 31 follows the objective lens 32 to move the optical head 3 to a target track.

In this fine seek, as in the coarse seek described above, the number of pulses of the binary signal (track count signal) is counted by a counter (not shown) from the start of the fine seek. That is, the passage of the track of the optical head 3 is detected, and the number of tracks is decremented by one each time the optical head 3 passes one track, whereby the number of tracks remaining until the target track is obtained.

When the counted value (the number of pulses) reaches the target number of passing tracks (when the number of remaining tracks up to the target track becomes 0), the precise seek, that is, the target track of the optical head 3 is performed. Movement ends.

The timing chart shown in FIG. 4 shows a case where the number of brake pulse signals is one, that is, the braking operation (braking) is performed once when the sled motor 7 is braked. FIG. 9 shows a case where the pulse number of the pulse signal is two, that is, the braking operation is performed twice intermittently (intermittently) when the sled motor 7 is braked.
The operation at this time will be described later in detail.

In the optical disk device 1, when the rotation speed is constant (CAV), the optical head 3 is moved to the target track while the rotation speed of the spindle motor 11 is kept constant.

When the linear velocity is constant (CLV),
When the optical head 3 is moved to the target track (especially during the movement of the optical head 3), the rotation speed of the spindle motor 11 is changed to the rotation speed when the optical head 3 is located at the target track.

Next, the control operation of the control means 9 when the optical head 3 is moved to the target track (target address), that is, the target position _Xc will be described.

FIG. 10 is a flowchart showing the control operation of the control means 9 when the optical head 3 is moved to the target track. Hereinafter, description will be made based on this flowchart.

As shown in the figure, with tracking (tracking control) ON, the Q channel code of the current track (access start track) is reproduced, and from the Q channel code, the current position (access start position) X
The address of _o (current address) _Ao is read. And
Based on the current address _Ao , the number of tracks from the reference track to the current track (the reference track number is "0")
_Is determined (step 101).

This step 101 has been performed before step 102, which will be described later.

In this embodiment, the reference track is, for example, the innermost track of the optical disc 2.

When an access execution (access start) command is input from a computer (not shown), the optical head 3
The operation (access) of moving to the target track (target address), that is, the target position _Xc is started (step 102).

In this step 102, the address (target address) _Ac of the target position _Xc is input from the computer, and the target address _Ac is read.

[0104] Then, on the basis of the target address A _c, the number of tracks from the reference track to the target track seeking (the number of reference track object number of the track when the "0") T _c, the T _c It is stored in the memory 10 (step 103).

[0105] Then, determine the T _c -T absolute value of _o (target passing number of tracks of the optical head 3) N _c (Step 10
4).

Next, it is determined whether or not N _c <120 (= N ₀ ) (step 105). If it is determined in step 105 that _Nc ≧ 120, the tracking is turned off (step 106), and it is determined whether _Nc <1500 (step 107).

In step 107, N _c ≧ 150
If 0 is determined _{is, N c <8000 (= N} 1) determines whether or not (step 108).

In step 108, N _c ≧ 800
When it is determined to be 0, as described above, + 5V, 2
A coarse seek is started by applying a head feed pulse voltage of 5 ms to the thread driver (step 109). By this step 109, the sled motor 7 rotates in a predetermined direction, and the optical head 3 moves toward the target track.

From the start of the coarse seek, as described above, every time one pulse of the track count signal is detected, N _c
Is decremented by one ( _Nc = _Nc- 1), and this _Nc is set as the number of remaining tracks up to the target track.

Next, it is determined whether or not the number N _c of remaining tracks up to the target track is 3000 (first value) (step 112).

In step 112, N _c = 300
When it is determined to be 0, as described above, -5V, 1
A first braking operation in braking the sled motor 7 is performed by applying a brake pulse voltage of 5 ms to the sled driver (step 113).

That is, when the number of remaining tracks up to the target track reaches 3000, a voltage of -5 V is applied to the sled driver, and the first braking operation in braking the sled motor 7 is started. The application of the voltage of -5 V is performed for a period of 15 ms.

The application time (pulse width) of the brake pulse voltage (drive voltage of the sled motor 7) in the first braking operation is determined by the brake pulse voltage (drive voltage of the sled motor 7) in the second braking operation described later. It is longer than the application time (pulse width).

By this step 113, the rotation speed (rotation speed) of the sled motor 7 decreases, and the moving speed of the optical head 3 decreases.

Next, it is determined whether or not the number N _c of remaining tracks up to the target track is 800 (second value) (step 114). Note that first value> second value.

In step 114, N _c = 800
If it is determined that, as described above, -5 V, 5 ms
Apply the brake pulse voltage of
A second braking operation in braking the thread motor 7 is performed (step 115).

That is, when the number of remaining tracks up to the target track reaches 800, a voltage of −5 V is applied to the sled driver, and the second braking operation in braking the sled motor 7 is started. The application of the voltage of -5 V is performed for a period of 5 ms.

Next, it is determined whether or not the number N _c of remaining tracks up to the target track is 80 (step 116).

If it is determined in step 116 that N _c = 80, tracking is turned on (step 117).

In step 108, N _c <
8000, that is, 1500 ≦ N _c
In the case of <8000, as described above, +5 V, 20
A coarse seek is started by applying a head feed pulse voltage of ms to the thread driver (step 111). By this step 111, the sled motor 7 rotates in a predetermined direction, and the optical head 3 moves toward the target track.

From the start of the coarse seek, as described above, N _c every time one pulse of the track count signal is detected as described above.
Is decremented by one ( _Nc = _Nc- 1), and this _Nc is set as the number of remaining tracks up to the target track.

Next, it is determined whether or not the number N _c of remaining tracks up to the target track is 800 (step 114).

In step 114, N _c = 800
If it is determined that, as described above, -5 V, 5 ms
Apply the brake pulse voltage of
The thread motor 7 is braked (step 115).

That is, when the number of remaining tracks to the target track reaches 800, a voltage of -5 V is applied to the sled driver, and braking (braking operation) of the sled motor 7 is started. The application of the voltage of -5 V is performed for a period of 5 ms.

Next, step 116 and subsequent steps are executed as described above. In step 107, N _c
<1500, that is, 120 ≦ N _c
In the case of <1500, as described above, +5 V, 5 ms
Is applied to the thread driver to start coarse seek (step 110). By this step 110, the sled motor 7 rotates in a predetermined direction, and the optical head 3 moves toward the target track.

From the start of this coarse seek, N _c every time one pulse of the track count signal is detected as described above.
Is decremented by one ( _Nc = _Nc- 1), and this _Nc is set as the number of remaining tracks up to the target track.

Next, step 116 and subsequent steps are executed as described above. After the execution of step 110 or 115, after a lapse of a predetermined time (minute time), the thread motor 7 stops, and the optical head 3 stops on or near the target track.

In step 105, N _c <
120, or in step 117
Thereafter, the Q channel code of the current track is reproduced, and the address (current address) _Ao of the current position _Xo is read from the Q channel code. Then, based on the current address A _o, the number of tracks from the reference track to the current track seek (the number of the reference track current track number when the "0") T _o, absolute T _c -T _o Value N _c
Is obtained (step 118).

Next, it is determined whether or not _Nc = 0, that is, whether or not the current address _Ao and the target address _Ac match (whether or not _Ac = A) (step 119).

In step 119, N _c = 0 is not _satisfied , that is, the current address A _o and the destination address A _c
If it is determined that does not match, precision seek is performed as described above (step 120). As described above, in this precision seek, the optical head 3 is moved to the target track by driving the actuator 4 to move the objective lens 32 in the radial direction.

With this precision seek, N _c = 0, and
That is, the current address A _o and the target address A _c match (step 121).

After the step 121 or in the step 119, the current address A _o and the destination address A
If it is determined that _c matches, this program is terminated. After the access is completed, reproduction is performed as described above.

As described above, according to the optical disk device 1, when the optical head 3 is moved to the target track (target address), the driving pattern of the thread motor 7 suitable for the target track number is determined according to the target number of tracks. That is, since the value of the drive voltage (head feed pulse voltage and brake pulse voltage) and application time of the thread motor 7 are set, the accuracy of the coarse seek is improved (the variation of the stop position of the optical head 3 in the coarse seek is suppressed). Thus, the time required for moving the optical head 3 to the target track (target address) (access time) can be shortened.

[0134] If the target passing track number of N ₁ or more, the number of pulses of the brake pulse signal (voltage) 2
When the coarse seek is performed, the optical head 3 is stopped by intermittently performing the braking operation twice while detecting the number of tracks remaining until the target track. Even so, it is possible to reduce or prevent the influence on the coarse seek, thereby further improving the accuracy of the coarse seek, thereby shortening the access time.

According to the optical disk device 1, when the optical head 3 is moved to the target track (target address), the tracking error signal is transmitted to the limiter amplifier 41.
Therefore, even when the tracking error signal contains a noise component or when the level of the tracking error signal is low, the tracking error signal can be reliably binarized. Can be accurately counted.

As a result, the accuracy of the coarse seek is further improved,
As a result, the access time can be shortened.

Further, at the time of rough seek, the rotation speed of the sled motor 7 is controlled by the speed control means so that the moving speed of the optical head 3 becomes constant, so that the rotation of the sled motor 7 at the brake start position _Xa is performed. rate, i.e., the moving speed of the optical head 3 is constant in the brake starting position X _a.

For this reason, it is possible to suppress variations in the radial distance from the brake start position _Xa (brake start track) to the coarse seek end position _Xb (coarse seek end track). Accuracy is further improved, and access time can be shortened.

In the coarse seek operation, the speed control means controls the rotation speed of the sled motor 7 so that the moving speed of the optical head 3 is constant.
Can be moved more stably.

The optical disk device of the present invention is compatible with the aforementioned CD.
-Not limited to the ROM drive device, for example, a CD
Various types of optical disc devices for recording and reproducing recordable and reproducible optical discs (optical discs having pre-grooves), such as -R, CD-RW, DVD-R, DVD-RAM, and CDs
(Compact discs) and other read-only optical discs,
The present invention can be applied to various types of optical disk devices for reproducing a recordable / reproducible optical disk.

The optical disk device of the present invention can be applied to various optical disk devices for recording and / or reproducing a plurality of types of optical disks.

The optical disk device of the present invention has been described based on the illustrated embodiment. However, the present invention is not limited to this, and each component may have any configuration having the same function. Can be replaced by

For example, the driving pattern of the sled motor 7 when the optical head 3 is moved to the target position on the optical disk 2 is not limited to the driving pattern of the sled motor 7 in the above embodiment.

In this case, for example, in the above embodiment, the driving pattern of the sled motor 7 is set by changing the application time (pulse width) of the driving voltage of the sled motor 7, but in the present invention, The driving pattern of the sled motor 7 may be set by changing the value of the driving voltage of the sled motor 7, and the sled motor 7 may be configured by changing the value of the driving voltage and the application time of the sled motor 7. 7 may be configured to be set.

In the above-described embodiment, the number of drive patterns of the thread motor 7 when the optical head 3 is moved to the target position on the optical disk 2 is three. There may be four or more patterns.

In the present invention, the braking operation of the sled motor 7 may be performed three or more times when braking.

Further, in the above embodiment, the application time (pulse width) of the brake pulse voltage (the drive voltage of the sled motor 7) in the first braking operation is different from the brake pulse voltage (the sled motor 7) in the second braking operation. Drive voltage)
However, the present invention is not limited to this. For example, the absolute value of the brake pulse voltage (the drive voltage of the sled motor 7) in the first braking operation is determined by the brake in the second braking operation. The absolute value of the pulse voltage (the drive voltage of the sled motor 7) may be larger than the absolute value of the pulse voltage (the drive voltage of the sled motor 7) and the application time (pulse width) of the brake pulse voltage (the drive voltage of the sled motor 7) in the first braking operation. The absolute value and the application time (pulse width) of the brake pulse voltage (drive voltage of the sled motor 7) in the second braking operation may be longer (longer).

In the present invention, for example, the absolute value and / or application time (pulse width) of the brake pulse voltage (drive voltage of the sled motor 7) in the first braking operation
May be smaller (shorter) than the absolute value and the application time (pulse width) of the brake pulse voltage (drive voltage of the sled motor 7) in the second braking operation, but the coarse seek accuracy can be further improved. At this point, the absolute value and / or application time (pulse width) of the brake pulse voltage (drive voltage of the sled motor 7) in the first braking operation is changed to the brake pulse voltage (drive voltage of the sled motor 7) in the second braking operation. It is preferable to make the absolute value and / or the application time (pulse width) longer (longer).

In the above embodiment, when the moving speed of the optical head 3 converges to a substantially predetermined value, the optical head 3
Although the speed control of the optical head 3 (rotation speed control of the sled motor 7) is started so that the moving speed of the optical head 3 becomes constant, in the present invention, the start position of the speed control of the optical head 3 is The present invention is not limited to this, and may be, for example, immediately after the start of acceleration of the optical head 3 (immediately after the start of movement).

In the present invention, the detecting means for detecting the rotation speed of the motor (thread motor 7) is not limited to the MR element 21, but may be constituted by various magnetic sensors such as a Hall element or various optical sensors. Good.

[0151]

As described above, according to the optical disk apparatus of the present invention, when the optical head is moved to the target position on the optical disk, the motor (thread motor) is driven in accordance with the number of tracks through which the optical head passes. Since the pattern is set, the accuracy of the coarse seek is improved, so that the time required for moving the optical head to the target position (access time) can be shortened.

When braking the motor (thread motor) when moving the optical head to the target position on the optical disk, and when performing the braking operation a plurality of times, especially when braking the motor, the optical head is also used. In the case where the passage of a track is detected and the number of remaining tracks to the target position is obtained, the accuracy of the coarse seek can be further improved, and the access time can be further shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment (main part) of an optical disk device of the present invention.

FIG. 2 is a plan view showing an embodiment (with a casing removed) of the optical disk device of the present invention.

FIG. 3 is a timing chart when the optical head is moved to a target track by performing a coarse seek and a fine seek in the present invention.

FIG. 4 is a timing chart when the optical head is moved to a target track by performing a coarse seek and a fine seek in the present invention.

FIG. 5 is a block diagram illustrating a configuration example of a speed control unit according to the present invention.

FIG. 6 is a block diagram illustrating a configuration example of a circuit that generates a binary signal (track count signal) of a tracking error signal in the present invention.

FIG. 7 shows a tracking error signal and 2 in the present invention.
9 is a timing chart showing a digitized signal (track count signal) and a binarized signal (track count signal) in a conventional device.

FIG. 8 is a timing chart showing a brake pulse signal when the brake is performed once in the present invention.

FIG. 9 is a timing chart showing a brake pulse signal when the brake is performed a plurality of times in the present invention.

FIG. 10 is a flowchart showing a control operation of a control unit when the optical head is moved to a target track in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical disk apparatus 2 Optical disk 3 Optical head 31 Optical head main body 32 Objective lens 311 Support part 4 Actuator 5 Laser diode 6 Split photodiode 7 Thread motor 8 Rotation axis 81 Lead screw 9 Control means 10 Memory 11 Spindle motor 12 Rotation axis 13 Turntable Reference Signs List 14 reduction gear 141 worm wheel 142 pinion gear 15 rack gear 16 guide shaft 17 disk 21 MR element 22 moving speed signal generator 23 amplifier 41 limiter amplifier circuit 42 waveform shaping circuit 51 waveform 101 to 121 step

Claims (10)

[Claims] A rotating drive mechanism for mounting and rotating an optical disc; an optical head movably mounted in a radial direction of the optical disc; and a motor, wherein the optical drive is arranged in a radial direction of the optical disc with respect to the optical disc. An optical disc device for recording and / or reproducing the optical disc, comprising: an optical head moving mechanism for moving a head, wherein a track through which the optical head passes when the optical head is moved to a target position on the optical disc An optical disc device, comprising: setting means for setting a drive pattern of the motor in accordance with the number. 2. The optical disk device according to claim 1, wherein a drive pattern of the motor is set by changing a braking condition of the motor. 3. The optical disk device according to claim 1, wherein a drive pattern of the motor is set by changing a value of a drive voltage and / or an application time of the motor. 4. The motor according to claim 1, wherein when the optical head is moved to a target position on the optical disk, braking operation of the motor can be performed a plurality of times. An optical disk device according to any one of the above. When wherein said number of tracks which the optical head passes the reference value N ₁ or more when moving the optical head to a target position on the optical disc, the setting means,
5. The optical disk device according to claim 4, wherein a drive pattern of the motor is set such that a braking operation is performed a plurality of times when the motor is braked. 6. The optical disk device according to claim 4, wherein when the braking operation is performed a plurality of times, the braking operation is performed intermittently. 7. When the optical head is moved to a target position on the optical disk, there is provided a remaining track number detecting means for detecting passage of a track of the optical head to obtain a remaining track number to the target position. 7. The optical disk device according to claim 1, wherein when the remaining track number obtained by said remaining track number detecting means reaches a predetermined value, braking of said motor is started. 8. The remaining track number detecting means is configured to detect passage of the track of the optical head and determine the number of remaining tracks to the target position even when the motor is braked. 8. The optical disk device according to 7. 9. When the optical head is moved to a target position on the optical disk, the optical head has a remaining track number detecting means for detecting passage of a track of the optical head and obtaining a remaining track number to the target position, When performing the braking operation a plurality of times, when the number of remaining tracks obtained by the remaining track number detecting means reaches a first value, a first braking operation in braking the motor is started, and the number of remaining tracks is reduced. 7. The motor according to claim 4, wherein a second braking operation in braking the motor is started when the number of remaining tracks obtained by the detecting means reaches a second value smaller than the first value. An optical disc device according to any one of the above. 10. The optical disk device according to claim 9, wherein an absolute value and / or an application time of the drive voltage of the motor in the first braking operation is longer than that in the second braking operation.