JP3530577B2 - Track access device for optical disk - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recording information on a track.
Recorded or already recorded information is played
The present invention relates to an optical disk track access device. 2. Description of the Related Art In recent years, laser light has been used as a light source.
The light is modulated by a pulse signal from an external information source,
By irradiating a disc-shaped optical recording medium,
Optical information recording / reproduction that records or reproduces information on the body
Various devices have been developed. In such an optical information recording / reproducing apparatus,
In order to record or reproduce information accurately,
So that the focal point of the light is located on the recording surface of the optical recording medium.
Focus control is performed, and light spots are
Track so that the
Control is performed to access the optical head to the desired track.
Recording or reproducing information. By the way, when the optical head is moved to another track.
In the so-called seek operation, the optical head is
The head actuator applies force perpendicular to the track.
Decelerate and perform coarse positioning (coarse seek operation).
Moves the condenser lens of the optical head by the lens actuator
Performed by two-step control for precise positioning (fine seek)
Had been. However, in such seek control,
Moves the entire optical head by the head actuator
When performing a seek, it is important to speed up the seek.
It is necessary to generate a large acceleration, but such a large
When acceleration is received by the optical head, the optical head collects during acceleration / deceleration.
The position of the optical lens is greatly displaced and damped vibration occurs.
Immediate seek after coarse seek due to damping vibration during deceleration
Cannot be performed, and as a result, a high-speed seek operation cannot be performed.
No. Therefore, for example, Japanese Patent Application Laid-Open No. 61-177640.
As shown in the publication, the focusing lens is moved at the reference speed.
Control the head actuator by the condensing lens of the optical head
Light so that the position in the tracking direction with respect to
By moving the head, it moves to the desired track
Track access devices have been proposed. In this track access device, as shown in FIG.
As described above, the condenser lens 2 mounted on the optical head 1
Recording medium 3 in which the light spot condensed is an optical disk
Irradiates the information track on the
Is played. The condenser lens 2 has at least the information
In the direction perpendicular to the rack, the lens actuator 4
Elastic support so as to be relatively movable with respect to the optical head 1.
It is connected to the base part 6 of the optical head 1 by a holding body 5
ing. The lens position sensor 7 is located in front of the condenser lens 2.
The position with respect to the base portion 6 is detected and the lens position signal is obtained.
Output. A light detector 8 is mounted on the optical head 1.
To detect the reflected light of the light spot irradiated on the recording medium 3
The tracking error detection circuit (TES circuit) 9
Indicates the position deviation between the light spot and the information track.
To obtain an error signal. The optical head 1 is a head actuator
10 moves in the direction perpendicular to the information track
It is supposed to be. Positioning a light spot on a specific track
Input the track error signal to the phase compensation circuit 11
After performing phase compensation to stabilize the servo system,
The signal is amplified by the amplifier 13 through the switching circuit 12.
Then, an input is made to the lens actuator 4. Lens acti
The concentrator 4 focuses the track error signal so that it becomes zero.
Adjust the position of the lens 2. The lens position signal is converted to a phase compensation circuit 14.
After compensating for servo system stabilization by
Amplified by the width circuit 15, the head actuator 10
To enter. As a result, the optical head 1 generates a lens position signal.
Zero, that is, the condenser lens is attached to the base 6 of the optical head 1.
It is positioned so as to be in the neutral position. [0010] Then, different from the current track,
When moving the light spot to the next track (during seek operation)
Is the moving track from the external control circuit 21 to the target track.
The number of locks is preset in the counter 22 and the counter
The output is a reference speed generating circuit 23 and a control circuit.
24. The pulsing circuit 25 detects a tracking error.
Generates a pulse corresponding to the zero crossing of the difference signal, and
The looseness is input to the counter 22 and the speed detection circuit 26.
The counter 22 is pulsed from the preset counter value.
The count value is decremented each time
The road 23 has a reference speed preset according to the count value.
Output degrees. The speed detection circuit 26 detects the input pulse
The moving speed of the light spot is detected from the cycle and output. Base
The quasi-speed signal and the speed detection signal are input to the speed error detector 27
The speed error is calculated. Output of speed error detector 27
The force is input to the polarity inversion circuit 28, and the external control circuit 21
The polarity is inverted according to the output moving direction instruction signal.
After that, it is input to the switching circuit 12. The control circuit 24 moves the light spot.
At the start, the switching circuit 12 is controlled, and the polarity inversion circuit 28 is controlled.
Is selected as the output of the switching circuit 12.
To As a result, the output of the polarity inversion circuit 28 is
13 and input to the lens actuator 4.
The light spot follows the reference speed and moves in the direction of the target track.
The speed is controlled to move toward. Target track
Control circuit 24 switches
By controlling the circuit 12 and switching to the side of A, the light spot is
It is positioned on the target track. SUMMARY OF THE INVENTION
As disclosed in Japanese Unexamined Patent Publication No. 61-177640,
Access device moves light spot to another track
At this time, as shown in FIG.
The optical head so that the displacement with respect to the
Since it is moved following the optical lens, it is shown in FIG.
When moving the optical head by speed control, the lens
Acceleration in the moving direction to the condenser lens by the actuator
Need to be actuated, and the lens actuator
As shown in (c), the drive current is always supplied during acceleration / deceleration.
There must be. On the other hand, light spots from one track to another track
To reduce the seek time required to move the
Moving the optical head with higher acceleration
Is required. Therefore, the lens actuator is also large.
Although it is necessary to generate acceleration,
Sufficient current cannot flow due to the limit, and seek time
There is a problem that cannot be shortened. Further, the conventional optical head described above is
Acceleration and deceleration in the direction perpendicular to the truck by the actuator
Perform coarse positioning (coarse seek operation), and then
Move the condenser lens of the optical head with a tutor to fine-tune
Seek operation by two-stage control to perform positioning (fine seek)
The track access device that performs
The position of the condenser lens of the pad is greatly displaced and damped vibration occurs
Drive current during acceleration / deceleration.
Similar problems have to be supplied and hold the condenser lens
have. The present invention has been made in view of the above circumstances.
Optical disk that can reduce seek time
To provide truck access equipment
You. Means for Solving the Problems and Function of the Invention
The disk track access device records or records information.
Irradiating a light beam on the track of the optical disc to be reproduced
A head actuator for driving an optical head;
The collection provided in the pad and held by the restoring force acting means
A lens actuator for driving the optical lens.
A track access device for an optical disc,
The position of the optical lens in the track direction with respect to the optical head is
Lens position detecting means for detecting, and the lens position detecting means
The converging lens detected by the step corresponds to the optical head.
The detected position relative to the neutral point of the restoring force acting means,
The light spot focused by the focusing lens is moved.
In the opposite direction of the target track or
Lens position target generation that generates a position target value shifted in the direction
Means for detecting an error between the detected position and the target position value
And a position error detecting unit that performs
From the current track to the target
When moving to the track, the output of the position error detection means
Therefore, the lens actuator is controlled, and
The target position value is changed from the current track to the target track.
During the travel to, where the position target value is
When moving to the target track,
Value corresponding to the position shifted in the opposite direction to the target track.
In the deceleration area, the vehicle does not move from the neutral position in the direction of the target track.
The value is a value corresponding to the position that has been set. Embodiments of the present invention will be described with reference to the drawings.
I do. Before describing the embodiments of the present invention,
A reference example of the embodiment will be described. First, a first reference example will be described. FIGS. 1 to 3 show a first embodiment according to the present invention.
1 relates to a reference example, and FIG.
FIG. 2 is a block diagram showing the track access device of FIG.
FIG. 3 is an explanatory view for explaining the operation of the track access shown in FIG.
Lens driving device for optical head controlled by scanning device
1 is an external view showing the configuration of FIG. As shown in FIG. 3, in the first reference example,
The condensing lens driving device 1a of the optical head 1
2 is, for example, a coil bobbin 52 formed by integral molding.
Fixed to the lens holder 53. And coil bobbin
52 is a restoring force acting means on a yoke 54 as a fixing member.
The optical axis is controlled by a rubber damper 55 in which certain four wires are inserted.
Moves in the optical axis direction and at right angles to the optical axis direction without tilting
Supported as possible. On both sides of the yoke 54, magnets 56 are provided.
The coil bobbin 52 is disposed between them.
A focus coil 57 is wound around the side surface of the coil bobbin 52.
Between the coil bobbin 52 and the magnet 56
Is provided with a tracking coil 58.
Pre-adjust the focus coil 57 and tracking coil 58
A current from a drive circuit mounted on the printed circuit board 59
As a result, the coil bobbin 52 is
Focus and track without tilting the optical axis of the optical lens 2
It is configured to be movable in the switching direction. The track of the optical disk of this embodiment is
In the access device, as shown in FIG.
The light spot condensed by the condensing lens 2
On the information track on the recording surface of the recording medium 3 which is an optical disc
It is illuminated and information is recorded or reproduced. Light collection
Lens 2 is at least a direction orthogonal to the information track.
The lens actuator 4 (the focus core in FIG. 3)
Il 57 and tracking coil 58).
Restoring force acting means so as to be movable relative to the head 1
Elastic support 5 (rubber damper 55 in FIG. 3)
The base portion 6 of the optical head 1 (Y in FIG.
(54). The lens position sensor as lens position detecting means
The sensor 7 is provided on the base 6 of the condenser lens 2.
The position is detected and a lens position signal is output. Optical head 1
Is provided with a photodetector 8 for irradiating the recording medium 3 with light.
The reflected light of the reflected light spot is detected and tracking error detection is performed.
A light spot by an output circuit (hereinafter referred to as a TES detection circuit) 9
And a track error signal indicating the displacement of the information track
You. In addition, the optical head 1 receives the light from the lens position sensor 7.
To the head actuator 10 based on the lens position signal.
Therefore, it is moved in a direction orthogonal to the information track.
Swelling. Positioning a light spot on a specific track
The tracking error signal from the TES detection circuit 9
Input to the phase compensation circuit 11 to stabilize the servo system.
After performing the phase compensation, an amplifier is passed through the switching circuit 12.
13 amplifies the signal and enters the lens actuator 4
Power. The lens actuator 4 outputs a track error signal
Is adjusted so that is set to zero. Ma
The lens position signal from the lens position sensor 7 will be described later.
Lens position error detection circuit 3 as position error detection means
3 to the phase compensating circuit 14 and output to the phase compensating circuit 1
After performing compensation for stabilizing the servo system in step 4,
Amplified by the path 15 and enters the head actuator 10
Power. As a result, the optical head 1 loses the lens position signal.
B, that is, the condenser lens 2 is attached to the base 6 of the optical head 1.
It is positioned so as to be in the neutral position. [0027] Then, from the current track,
When moving the light spot to the next track (during seek operation)
Is the moving track from the external control circuit 21 to the target track.
The number of locks is preset in the counter 22 and the counter
The output is a reference speed generating circuit 23 and a control circuit.
24. The pulse conversion circuit 25 is a TES detection circuit
9 corresponding to the zero crossing of the tracking error signal from
Generates a pulse that is detected by the counter 22 and speed
Input to the circuit 26. The counter 22 is preset
The pulse from the pulsing circuit 25 is input from the counter value
Count value is decremented each time the
Speeds up a preset reference speed according to the count value.
It is output to the degree error detector 27. The speed detection circuit 26
Is the moving speed of the light spot from the period of the input pulse.
Detected and output to the speed error detector 27. Speed error detection
In the detector 27, based on the input reference speed signal and speed detection signal,
A speed error is calculated. The output of the speed error detector 27 is
Input to the polarity inversion circuit 28 and output from the external control circuit 21
The polarity is inverted according to the moving direction instruction signal. That
Thereafter, it is input to the switching circuit 12. The control circuit 24 shifts the light spot.
At the start of operation, the switching circuit 12 is controlled to the side of B,
The output of the switching circuit 28 is selected as the output of the switching circuit 12.
To be done. As a result, the output of the polarity inversion circuit 28 is output.
The force is amplified via the amplifier 13 and the lens actuator
4 and the light spot follows the reference speed and
The speed is controlled to move in the direction of the lock.
When reaching the vicinity of the target track, the control circuit 24
Controls the switching circuit 12 to switch to the A side,
The spot is positioned on the target track. The counter 22 counts the count value at the lens position.
The lens position target value generation circuit 31 as a target generation means also
Output, and the lens position target value generation circuit 31
Lens position preset according to the count value of the
The target value is output to the polarity inversion circuit 32. And polarity reversal
In the circuit 32, external control is performed according to the moving direction at the time of access.
According to the direction signal output from the circuit 21, the lens
The position target value is inverted in polarity. Output of polarity inversion circuit 32
Is input to the lens position error detection circuit 33, and the lens position
The error detection circuit 33 outputs the output of the lens position detector 6.
The difference from the lens position signal is calculated. Lens position error detection
The output of the circuit 33 is input to the phase compensating circuit 12 and is complemented.
After being compensated, it is amplified by the amplifier 13 and the head
Input to the actuator 10. This allows the light head
1 is a relative position between the condenser lens 2 and the base 6 of the optical head 1.
The misalignment matches the output of the lens position target value generation circuit 31
Is controlled. Here, the lens position target value generating circuit 31
Indicates that the reference speed increases according to the output of the counter 22.
Acceleration range, constant speed range where reference speed is constant, reference speed decreases
The output that is the lens position target value in each area of the deceleration area
To either the constant value on the minus side, zero, or the constant value on the plus side.
Change. The lens position target value is determined by the focusing lens 2 and the recording medium.
In the acceleration region in which the relative speed of 3 is increased, the condenser lens 2
Shifts with respect to the base portion 6 in the direction opposite to the moving direction, and
In the constant speed area where the robot moves at a constant speed, it is in the neutral position,
In the region, it is generated so as to shift to the moving direction side. With this configuration, the configuration of the present embodiment can be improved.
In the rack access device, the conventional method described above (see FIG. 7)
The driving signal of the tracking actuator is
A value corresponding to the acceleration determined by the rate of change of the quasi-speed
However, the acceleration by the speed control shown in FIG.
Except immediately after the start of deceleration, as shown in FIG.
The drive signal of the actuator 4 is kept near zero.
ing. As shown in FIG.
When the lens 2 is shifted, the elastic support 3
A restoring force is applied according to the shift amount and direction.
Moves the optical head 1 when the optical head 1 is moved.
Necessary to keep the relative position of the lens 6 and the condenser lens 2 constant.
Since the speed is generated, the lens actuator 4 is focused.
Accelerate or decelerate by applying force to lens 2
This is because there is no need. Therefore, as shown in FIG.
The drive signal of the actuator 4 should be approximately zero.
The current flowing through the coil of the lens actuator 4 can be reduced.
It is possible to shorten the seek time while keeping it short. It should be noted that shifting the lens from the neutral position is accelerated.
It does not need to be both at the time and at the time of deceleration. That is, when accelerating
Or deceleration in either case during deceleration,
Has the effect of reducing the current flowing through the lens actuator 4.
And seek time can be reduced. In the track access device of the present embodiment,
Fig. 3 shows the condensing lens driving device of the optical head controlled by
However, the configuration is not limited to this.
Lens with a configuration in which the objective lens is supported by the application means
What is necessary is just a drive device. (1) The restoring force acting means is constituted by a linear elastic support member.
See, for example, Japanese Patent Application Laid-Open No. 62-287440.
Lens driving device, (2) generating a restoring force by means of magnetic attraction to the restoring force acting means
For example, JP-A-1-317234
(3) Restoring force acting means is slidable and the lens is made of rubber or the like.
It is configured to be held at the neutral position.
(4) An example in which the restoring force acting means is constituted by a rotating hinge.
For example, a lens drive disclosed in Japanese Patent Application Laid-Open No. 4-147440 is disclosed.
(5) The restoring force acting means is constituted by a leaf spring, for example,
Lens driving device disclosed in JP-A-5-28508
A configuration such as that described above may be used. Next, a second reference example will be described. FIG. 4 shows a track access according to the second reference example.
FIG. 2 is a block diagram illustrating a configuration of the device. The second reference example is the first
Since it is almost the same as the reference example, only different configurations are explained
The same components are denoted by the same reference numerals, and description thereof is omitted. In the track access device of the second reference example,
As shown in FIG. 4, the output of the reference speed generation circuit 23 is differentiated.
It is input to a circuit 61 to detect a change in the reference speed, that is, acceleration.
Put out. The output of the differentiating circuit 61 enters the level determining circuit 62.
The acceleration is (1) positive, (2) near zero,
(3) Determine which area is negative, and
Switching circuit 6 as lens position target generating means in response
3 output is switched to one of "-C", "0", "+ C"
Replace it. The output of the switching circuit 63 is connected to the polarity inversion circuit 32
To the lens, invert the polarity according to the moving direction,
It is input to the position error detection circuit 33. Other configurations, functions and effects are described in the first reference example.
Is the same as Although not shown, the speed error detector 27
By inputting the output to the level judgment circuit 62, the speed error
Switch the lens position target value according to the polarity of the output of the detector 27.
It may be configured to switch. As in the first embodiment, the condensing lens 2
Shift from the neutral position not only during acceleration and deceleration,
In the case of either acceleration or deceleration
The current flowing through the lens actuator
It has the effect of reducing. Next, an embodiment of the present invention will be described. FIG. 5 shows a track access device according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of the access device. In this embodiment, the light spot is set to a specific track.
When positioning in the same way as in the first reference example,
The tracking error signal from the detection circuit 9 is converted to a phase compensation circuit 11
Phase compensation for servo system stabilization
After that, the signal is sent to the amplifier 13 through the switching circuit 12.
The signal is amplified and input to the lens actuator 4. Lentua
The actuator 4 sets the track error signal to zero.
Adjust the position of the condenser lens 2. The lens position from the lens position sensor 7 is
Of the servo signal by the phase compensation circuit 14 for stabilizing the servo system.
After the compensation for the
Amplified by the circuit 15 and applied to the head actuator 10
input. As a result, the optical head 1 loses the lens position signal.
B, that is, the condenser lens 2 is attached to the base 6 of the optical head 1.
It is positioned so as to be in the neutral position. From the current track, another track
When moving the light spot to the
The number of tracks to be moved from the
It is preset and its counter output is
The signal is input to the path 23 and the control circuit 24. Pal
The conversion circuit 25 responds to the zero crossing of the tracking error signal.
The counter 22 generates a pulse in response to the pulse.
It is input to the degree detection circuit 26. The counter 22 has a preset
Every time a pulse is input from the counter value
The reference speed generation circuit 23 subtracts the count value.
And outputs a reference speed set in advance according to. Speed detection
The circuit 26 shifts the light spot from the period of the input pulse.
Detects and outputs dynamic speed. The reference from the reference speed generating circuit 23
The speed signal and the speed detection signal from the speed detection circuit 26 are
The speed error is input to the degree error detector 27 and is calculated. Speed
The output of the error detector 27 is input to a polarity inversion circuit 28.
In response to the movement direction instruction signal output from the external control circuit 21.
The polarity is then inverted, and then input to the switching circuit 71.
It is. The control circuit 24 starts the movement of the light spot
The switching circuit 71 is controlled to output the
Is selected as the output of the switching circuit 71.
You. As a result, the output of the polarity inversion circuit 28 is
5 and input to the head actuator 10.
The optical head 1 moves in the direction of the target track according to the reference speed.
The speed is controlled to move toward. The lens position target value generation circuit 31
Acceleration region where the reference speed is amplified according to the output of
Constant speed area where reference speed is constant, deceleration area where reference speed decreases
In each area of, output is constant value on the negative side, zero, constant value on the positive side
Switch to one of Lens position target value generation circuit 3
1 is input to the polarity inversion circuit 32,
Direction output from the external control circuit 21 depending on the moving direction
The polarity is inverted according to the instruction signal. Polarity inversion circuit 32
Is input to the lens position error detection circuit 33,
Difference from the lens position signal, which is the output of the
Is calculated. The output of the lens position error detection circuit 33 is the phase
After being input to the compensation circuit 72 and subjected to phase compensation, switching is performed.
The lens 13 is amplified by the amplifier 13 through the
Input to the actuator 4. This allows the focusing lens
2 is that the relative positional deviation of the optical head 1 with respect to the base 6 is low.
Position to match the output of the position
Is controlled. The target lens position value is determined by the optical head 1 and the recording medium.
In the acceleration region where the relative speed of the body 3 is increased, a condenser lens
2 has shifted to the opposite side to the moving direction with respect to the base portion 6
State, and moves at a constant speed.
And in the deceleration area, it is shifted to the direction of movement.
Generate so that The control circuit 24 controls the counter 22
The count value becomes almost zero and reaches near the target track
Switching circuit 12 and switching circuit 7
1 is switched to the A side, and the track positioning operation is started.
You. That is, in this embodiment, the tracking error
The output of the speed error detection circuit 27 based on the difference signal
Drive the head actuator to seek the optical head 1,
At that time, the lens actuator 4 is moved to the lens target position.
This is an embodiment in which the position is controlled.
The optical head to follow the movement of the focusing lens.
In this embodiment, the seek operation is performed by an optical head.
Make the condenser lens follow the lens target position for the movement of
It is done by doing. Therefore, in this embodiment, the effect of the first reference example is obtained.
In addition, it generally has lower performance than lens actuators
By controlling the speed with the head actuator,
Deriving the maximum speed that the head actuator can produce
Can be. The generation of the lens target position is determined by the lens position.
Although the target value generation circuit 31 has been used, the present invention is not limited to this.
First, the differentiation circuit 61 and the level determination circuit
62 and a switching circuit 63 (see FIG. 4).
Needless to say, the configuration may be such that As described above, the optical disc of the present invention is used.
According to the truck access device, the head actuator
The maximum speed at which the data can be output.
Tracks on optical discs that can reduce working time
An access device can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a configuration of a track access device which is a first reference example of an embodiment of the present invention. FIG. 2 is an explanatory diagram illustrating the operation of the track access device in FIG. FIG. 3 is an external view showing a configuration of a condensing lens driving device of an optical head controlled by the track access device of FIG. 1; FIG. 4 is a block diagram showing a configuration of a track access device which is a second reference example of the present invention; FIG. 5 is a block diagram showing a configuration of a track access device according to an embodiment of the present invention. FIG. 6 is a block diagram showing a configuration of a track access device according to a conventional example. [Explanation of reference numerals] 1 ... Optical head 2 ... Condensing lens 3 ... Recording medium 4 ... Lens actuator 5 ... Elastic support 6 ... Base 7 ... Lens position sensor 8 ... Photodetector 9 ... TES detection Path 10 Head actuators 11, 14, 72 Phase compensation circuits 12, 63, 71 Switching circuit 13 Amplifier 15 Amplifier circuit 21 External control circuit 22 Counter 23 Reference speed generation circuit 24 Control circuit 25 Pulse Conversion circuit 26 speed detection circuit 27 speed error detectors 28 and 32 polarity reversal circuit 31 lens position target value generation circuit 33 position error detection circuit 61 differentiation circuit 62 level determination circuit

Claims (1)

(57) [Claim 1] A head actuator for driving an optical head for irradiating a light beam to a track of an optical disk on which information is recorded or reproduced, and restoring force acting means provided in the optical head A track actuator for driving the condenser lens held by the optical disc, comprising: a lens actuator for driving the condenser lens held by the optical disc; and a lens position detector for detecting a position of the condenser lens in the track direction with respect to the optical head; The detection position of the condensing lens detected by the detecting means with respect to the optical head is in the opposite direction to the target track for moving the light spot condensed by the condensing lens with respect to the neutral point of the restoring force acting means or Lens position target generating means for generating a position target value shifted in the direction of the target track; Position error detection means for detecting an error between a detection position and the position target value, when the light spot condensed by the condenser lens is moved from a current track to the target track, the position error detection means The lens actuator is controlled by the output of, further, the position target value is changed while moving from the current track to the target track, and at this time, the position target value is, when moving to the target track, A track access device for an optical disk, wherein the value corresponds to a position deviated in a direction opposite to a target track in an acceleration area, and a value corresponding to a position deviated from a neutral position in a direction of a target track in a deceleration area.