JP2000113474A - Track jump controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a track jump controller capable of track-jumping with accuracy and high speed irrespective of a state of an optical disk such as warpage and wobbling of surface, and a structure of an optical pickup. SOLUTION: Receiving an instruction from a control part 14, a kick/brake pulse generating part 16 generates a kick pulse and a brake pulse necessary for track-jumping. If a signal level from the kick/brake pulse generating part 16 is expressed as Vtk, the level of the brake pulse is changed from -Vtk to a tracking error signal or a level -k.Vtk (k is less than 1) smaller than -Vtk halfway depending on the time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a track jump control device, and more particularly, to a track jump control device for jumping a light beam from a track currently being traced on an optical disk to an adjacent track.

[0002]

2. Description of the Related Art In an optical disk recording / reproducing apparatus for recording / reproducing data on / from an optical disk, an optical pickup follows a data track by a tracking servo so that a desired track can be appropriately accessed.

FIG. 18 is a block diagram of a tracking servo. The reflected light of the light beam applied to the optical disk 1 passes through the lens 2, is received by the light receiving unit 3, and is converted into the tracking error signal TE by the I / V conversion unit 4. The tracking error signal TE is amplified by the low-frequency boosting unit 5 for the low-frequency component, is phase-compensated by the high-frequency phase compensating unit 6, and is supplied to the switch 7. The switch 7 is normally set to the position N, and the output signal of the high-frequency phase compensator 6 is supplied to the tracking actuator 10 in the optical pickup 9 by the driver 8 to drive the lens 2. Thus, the light beam can be accurately traced to the track of the optical disc 1.

At the same time, track jump control is required to move a light beam to an adjacent track. As this control method, so-called bang-bang control, control using a pulse-type drive signal having a fixed time width and a fixed voltage level in which the polarity is reversed by kick and brake is performed. The kick / brake pulse generator 11 generates a kick pulse and a brake pulse necessary for a track jump, and receives a command from the controller 12 and supplies a kick pulse and a brake pulse to the switch 7. At this time, since the controller 12 switches the switch 7 to the position J, the kick pulse and the brake pulse are supplied to the tracking actuator 10 via the driver 8.

[0005] In the bang-bang control, however, the ideal optical pickup can move at the highest speed and the control system can be simplified, but the characteristics do not become constant in a normal optical pickup having a variation in spring constant and a somewhat nonlinear characteristic. Convergence worsens. Further, since the bang-bang control is a so-called open control, the accuracy is reduced due to the warpage of the disk or the like.
That is, the moving distance changes and an error occurs at the position immediately after the jump. Since the error needs to be converged by the tracking servo, the time of the tracking servo immediately after the jump becomes longer, and the time required for the track jump becomes substantially longer. Therefore, there is a problem that the repetition period of the jump becomes long.

[0006]

SUMMARY OF THE INVENTION The present invention provides a track jump control apparatus capable of performing a track jump accurately and at high speed irrespective of the state of an optical disk such as surface runout or warpage and the structure of an optical pickup. The task is to

[0007]

According to a first aspect of the present invention, there is provided a track jump control apparatus for causing a light beam to jump from a state where a light beam follows a track of an optical disk to an adjacent track. A jump control device, comprising: a signal generating unit that generates a kick signal and a brake signal for moving a light beam, wherein the magnitude of the brake signal is changed by a tracking error signal detected from an optical disc.

According to a second aspect of the present invention, there is provided a track jump control device.
The magnitude of the kick signal is changed by a tracking error signal detected from the optical disc.

According to a third aspect of the present invention, there is provided a track jump control device.
A track jump control device that causes a light beam to jump from a state where the light beam follows a track of an optical disk to an adjacent track, and has a signal generation unit that generates a kick signal and a brake signal for moving the light beam. The magnitude of the brake signal is changed after a predetermined time from the start of the supply of the brake signal.

According to a fourth aspect of the present invention, there is provided a track jump control device.
It is characterized in that the magnitude of the kick signal is changed after a predetermined time from the start of supply of the kick signal.

According to a fifth aspect of the present invention, there is provided a track jump control device comprising:
A track jump control device that causes a light beam to jump from a state where the light beam follows a track of an optical disk to an adjacent track, and has a signal generation unit that generates a kick signal and a brake signal for moving the light beam. The kick signal and the brake signal are changed according to the amount of change per unit time of the tracking error signal detected from the optical disk.

According to a sixth aspect of the present invention, there is provided a track jump control device.
A track jump control device that causes a light beam to jump from a state where the light beam follows a track of an optical disk to an adjacent track, and has a signal generation unit that generates a kick signal and a brake signal for moving the light beam. The kick signal and the brake signal are changed according to the result of comparing and calculating the tracking error signal detected from the optical disc and the target value of the tracking error signal.

Next, the operation will be described. In the track jump control device according to any one of the first to fourth aspects, the brake signal is not one kind of brake pulse but has a variable magnitude. Therefore, the moving speed of the light beam is rapidly reduced by a large brake signal, and the moving speed of the light beam is gradually reduced by a small brake signal. Thereby, the convergence of the tracking error signal after the track jump is improved. In particular, in the track jump control devices according to the second and fourth aspects, since the kick signal is not one kind but has a variable magnitude, the moving speed can be prevented from being excessively high.

According to a fifth aspect of the present invention, there is provided a track jump control device for determining an actual light beam speed during a track jump from a variation per unit time of a tracking error signal detected from an optical disk, and based on the speed. Since the track jump is controlled, an optimum track jump can be performed even for a disk having large surface runout and warpage.

A track jump control device according to a sixth aspect of the present invention compares a tracking error signal detected from an optical disk with target data for each sample to determine whether the target is faster or slower than a target, thereby determining a track jump. , It is possible to perform an optimal track jump even for a disk with large surface runout and warpage.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION
An example will be described. Note that components in the figure that have the same structure as the conventional technology are denoted by the same reference numerals.

<First Embodiment> In the first embodiment, not only one kind but also a plurality of levels of kick pulse and brake pulse for bang-bang control are prepared, and the level is changed midway as necessary. It is. FIG. 1 shows the first embodiment.
This will be described with reference to FIG. Here, FIG. 1 is a circuit block diagram of a tracking servo, FIG. 2 is a control flowchart, and FIG. 3 is a timing chart during a track jump.

First, a circuit block configuration will be described with reference to FIG. The tracking error signal TE generated from the return light of the light beam is input to the A / D converter 13,
The data is sequentially sampled at a predetermined sampling period and converted into error data SS1 which is digital data. A
The output of the / D converter 13 is supplied to the low-frequency boost unit 5 and the controller unit 14.

Further, the tracking error signal TE is input to the comparing section 15 and is compared with the waveform center level to be converted into a pulse. The zero-cross signal SS2, which is a pulsed signal, is supplied to the controller 14, and is used for zero-cross detection of the tracking error signal TE. Note that there is no offset of the tracking error signal TE,
It is assumed that the track center is at error 0.

The kick / brake pulse generator 16 receives a command from the controller 14 and generates a kick pulse and a brake pulse necessary for a track jump. The output signal of the kick / brake pulse generation unit 16 is added to a signal obtained by amplifying the output signal of the low-frequency boost unit 5 by the amplification unit 17 by the addition unit 18 and output to the switch 7. The reason for adding the signal from the low-frequency boost unit 5 is to compensate for the influence of track eccentricity during a track jump.

The switch 7 selects an output from the high-frequency phase compensator 6 or an output from the adder 18 in accordance with a command from the controller 14, and outputs the output to the D / A converter 19.
In the switch 7, the output of the high-frequency phase compensator 6 is normally selected, and in the case of a track jump, the output from the adder 18 is selected.

The D / A converter 19 converts a digital signal into an analog signal, outputs the signal to a tracking actuator via a driver (not shown), and drives the lens.
The controller unit 14 receives the error data SS1 and the zero-cross signal SS2, and controls a track jump. At this time, time measurement is performed using the timer 20.

Next, the control procedure of the controller section 14 will be described with reference to the circuit block diagram of FIG. 1 and the timing chart of FIG. 3 along the flowchart of FIG. 3A shows the tracking error signal TE, FIG. 3B shows the output signal of the kick / brake pulse generator, and FIG. 3C shows the zero cross signal SS2.

In step S101, the normal tracking servo is turned off by switching the switch 7 from the position N to the position J, and the kick / brake pulse generator 16 is supplied to the tracking actuator.
To be supplied. As a result, the lens of the optical pickup starts moving, and the light beam starts track jump. The signal level from the kick / brake pulse generator 16 is set to Vtk.

In step S102, it is determined whether the tracking error signal TE is higher than a predetermined level Vth + by using the error data SS1. If it is higher, proceed to step S103; if it is lower, this step S10
Repeat 2. This is the process for the next step.

In step S103, it is determined whether the tracking error signal TE is lower than a predetermined level Vth + by using the error data SS1. If it is low, proceed to step S104; if it is high, this step S10
Repeat 3. In step S104, a signal is sent to the kick / brake pulse generator 16 to reduce the kick pulse. As a result, the tracking actuator is supplied with a kick pulse having a level k · Vtk smaller than Vtk. Here, k is less than 1.

In step S105, it is determined whether the tracking error signal TE has crossed zero. This decision
This is performed by changing the polarity of the zero cross signal SS2 output from the comparator 15 from the H level to the L level as shown in FIG. Step S if zero cross
Proceeding to step 106, if there is no zero cross, this step S105 is repeated. The determination of the zero cross may be made based on the error data SS1.

In step S106, the kick / brake pulse generator 16 supplies a level-Vtk brake pulse. In addition, the timer 20 is reset, and the timer 20 starts time measurement. In step S107, it is determined whether or not the tracking error signal TE is lower than a predetermined level Vth- using the error data SS1. If low, step S10
Then, if it is higher, the step S107 is repeated.
This is the process for the next step.

In step S108, it is determined whether or not the tracking error signal TE is higher than a predetermined level Vth- by using the error data SS1. If it is higher, proceed to step S109; if it is lower, this step S10
Repeat step 8. In step S109, a signal is sent to the kick / brake pulse generator 16 to reduce the brake pulse. As a result, the tracking actuator is supplied with a brake pulse of level -kVtk, which is smaller than -Vtk.

In step S110, it is determined whether the time measured by the timer 20 is longer than a predetermined brake set time Tbj. If longer, the process proceeds to step S112, and if shorter, the process proceeds to step S111. This is a protection for a case where zero crossing of the tracking error signal TE cannot be found in the next step S111 due to dust on the disk or the like.

In step S111, it is determined whether the tracking error signal TE has crossed zero. This decision
This is performed by changing the polarity of the zero cross signal SS2 output from the comparison unit 15 from the L level to the H level as shown in FIG. Step S if zero cross
Proceed to 112. If zero-crossing has not occurred, step S
Return to 110. The determination of the zero cross may be made based on the error data SS1.

In step S112, the normal tracking servo is returned by switching the switch 7 from the position J to the position N. This ends the track jump.

<Second Embodiment> In the second embodiment, not only one kind but also a plurality of levels of the kick pulse and the brake pulse for the bang-bang control are prepared, and the level is changed midway if necessary. However, in the first embodiment, the timing at which the levels of the kick pulse and the brake pulse are changed by the level of the tracking error signal TE is determined by the time during which the kick pulse and the brake pulse are supplied. To decide.

The control procedure of the second embodiment will be described with reference to the circuit block diagram of FIG. 1 and the timing chart of FIG. 5 according to the flowchart of FIG. In FIG. 5, (a)
Is a tracking error signal TE, (b) is an output signal of a kick / brake pulse generator, and (c) is a zero cross signal SS2.

In step S201, the normal tracking servo is turned off by switching the switch 7 from the position N to the position J, and the kick / brake pulse generator 16 is supplied to the tracking actuator.
To be supplied. As a result, the lens of the optical pickup starts moving, and the light beam starts track jump. The signal level from the kick / brake pulse generator 16 is set to Vtk. In addition, the timer 20 is reset, and the timer 20 starts time measurement.

In step S202, it is determined whether the time measured by the timer 20 is longer than a predetermined pulse set time Tj. If it is longer, the process proceeds to step S203, and if shorter, step S202 is repeated. Thereby, the level V
The tk acceleration pulse is supplied to the tracking actuator for the time Tj.

In step S203, a signal is sent to the kick / brake pulse generator 16 to reduce the kick pulse. As a result, the tracking actuator has V
A kick pulse of level kVtk, which is smaller than tk, is supplied.

In step S204, it is determined whether the tracking error signal TE has crossed zero. This decision
This is performed by changing the polarity of the zero cross signal SS2 output from the comparator 15 from the H level to the L level as shown in FIG. Step S if zero cross
Proceeding to step 205, if there is no zero crossing, this step S204 is repeated. The determination of the zero cross may be made based on the error data SS1.

In step S205, the kick / brake pulse generator 16 supplies a level-Vtk brake pulse. In addition, the timer 20 is reset, and the timer 20 starts time measurement.

In step S206, it is determined whether the time measured by the timer 20 is longer than a predetermined pulse set time Tj. If it is longer, the process proceeds to step S207, and if shorter, step S206 is repeated. By this, level-
The Vtk brake pulse is supplied to the tracking actuator for the time Tj.

In step S207, a signal is sent to the kick / brake pulse generator 16 to reduce the brake pulse. As a result, the tracking actuator is supplied with a brake pulse of level -kVtk, which is smaller than -Vtk.

In step S208, it is determined whether the time measured by the timer is longer than a predetermined brake set time Tbj. If longer, the process proceeds to step S210, and if shorter, the process proceeds to step S209. This is dust on the disk, etc. In the next step S209, the tracking error signal T
Protection for when the zero crossing of E is not found.

In step S209, it is determined whether the tracking error signal TE has crossed zero. This decision
This is performed by changing the polarity of the zero cross signal SS2 output from the comparator 15 from the L level to the H level as shown in FIG. Step S if zero cross
Proceed to 210, and if there is no zero cross, step S
Return to 208. The determination of the zero cross may be made based on the error data SS1.

In step S210, the mode is returned to the normal tracking servo by switching the switch from position J to position N. This ends the track jump.

The control method shown in the first embodiment or the second embodiment, that is, a method in which the timing is determined by a tracking error signal and the levels of the kick pulse and the brake pulse are changed halfway, or The timing is determined by the time during which the pulse and the brake pulse are being supplied, and the moving speed of the lens is as shown in FIG. 6 by a method of changing the levels of the kick pulse and the brake pulse halfway. In FIG. 6, (a) shows the output signal of the kick / brake pulse generator, and (b) shows the moving speed of the lens. FIG.
In this case, an ideal optical pickup is assumed, and the speed may not be linear in an optical pickup having a large spring constant or a slightly nonlinear characteristic.

With these controls, the control time is later than in the conventional bang-bang control, but the convergence of the tracking error signal after the track jump is improved by slowing down the speed near the end of the track jump. Therefore, the actual track jump time from the start of the track jump to the end of the track jump and the normal tracking state of the tracking error signal is reduced.
Further, the stability with respect to the variation of the optical pickup is improved.

The levels of the kick pulse and the brake pulse can be changed not only in two steps but also in any number of steps. In the second embodiment, the time for applying the Vtk level is set to the same time Tj for kick and brake, but may be changed. The reason why the kick pulse is divided into two stages in the above embodiment is that when the lens speed becomes higher than a predetermined speed, the speed becomes extremely high by performing a slower acceleration than the acceleration as it is. This is so that it is not too much. For this reason, it is also possible to adopt a mode in which the kick pulse is not divided into two stages, and only the brake pulse is divided into two stages.

<Third Embodiment> Next, a third embodiment will be described. In the third embodiment, the movement speed of the lens is detected by calculating the change between the data of the immediately preceding tracking error signal and the data of the current tracking error signal, and the optimum kick signal is calculated based on the calculation result. And a brake signal are generated and supplied to the tracking actuator.

First, the fact that it is effective to detect the movement speed of the lens and control the speed will be described in detail.
Note that components in the figure that have the same structure as the conventional technology are denoted by the same reference numerals.

The two-axis actuator including the tracking actuator is considered as one vibration system, and can be replaced with a model shown in FIG. Although the tracking system differs from the focus system, various methods have been devised.
The model indicated by is a general method, and is an actuator of a type in which the lens 2 rotates around the movable center 21. In this case, the equation of motion with respect to the rotation angle θ is as shown in the following Expressions 1 and 2.

(Equation 1)

(Equation 2)

Where J is the inertia of the lens, kt is the spring constant, Rm is the mechanical resistance, T is the force, B is the magnetic flux density, L is
Is the coil side length, i is the actuator drive current, n is the number of coil turns, and R is the moving distance.

Assuming that ω ₀ and Q are equations 3 and 4, respectively,

(Equation 3)

(Equation 4) Equations (1) and (2) are Laplace transformed into Equation (5).

(Equation 5) Equation 6 is further obtained.

(Equation 6)

Here, if the moving distance X (S) is given by Expression 7, the following expression is obtained.
The transfer function G (S) is represented by Expression 8.

(Equation 7)

(Equation 8)

As described above, the relational expression between the driving current I (S) and the moving distance X (S) is obtained. When a track jump is performed, the servo loop is once opened and a pulse corresponding to the speed is applied, so that the above-described operation is performed.

Next, the characteristics of the light receiving side will be described. Light receiving method is 3-beam method for CD (Compact Disc), Push-Pull
A high-density disc such as a DVD (digital video disc) includes a DPD (Differential Phase Detection) method using an RF or pit phase as a signal source. In the three-beam method and the push-pull method, the tracking error signal is generated when the signal crosses the track as shown in FIG.
In the DPD method, an S-shaped waveform as shown in FIG.
A triangular wave as shown in FIG. The track pitch is about 1.6 μm for a CD, and 0.
It is 74 μm or less. When crossing this track, a tracking error signal waveform called a traverse signal shown in FIG. 8 is generated.

The tracking error signal PP (Peak to
Peak) voltage depends on the light receiving sensitivity and the circuit. If the optical system detecting sensitivity of the light receiving unit 3 is Kp and the conversion resistance of the subsequent I / V converting unit 4 is Riv, the tracking error signal within the focus pull-in range is obtained. The level Vte is represented by Expression 9.

(Equation 9)

FIG. 9 is a block diagram of the transfer function of this servo loop. In this case, since the servo loop is closed, a loop transfer function is obtained. The amplifying unit 22 is a general term for gain of a drive amplifier or the like.
From the block diagram of FIG. 9, the open-loop transfer characteristic Gop
(S) is represented by Expression 10.

(Equation 10)

When a track jump occurs, the servo system is in an open loop, and instead controls a kick signal. FIG. 10 shows a block diagram of the transfer function. From FIG. 10, when the kick signal Vtk (S) is generated and the tracking error Vte (S) is obtained, Equation 1 is obtained.
It becomes 1.

[Equation 11]

As described above, the moving distance X (S) of the actuator due to the kick signal is determined by the tracking error Vte
It can be seen that it can be expressed as the variation of (S). Therefore, the speed of the actuator, which can be expressed by the derivative of the moving distance of the actuator, can also be expressed by the amount of change per unit time of the tracking error Vte (S). Therefore, if the actuator speed is calculated from the amount of change per unit time of the tracking error Vte (S), and the kick pulse is changed based on the data, the speed control can be performed.

Next, a block diagram of the transfer function of this embodiment will be described with reference to FIG. The signal conversion unit 23 changes the kick signal and the brake signal based on a certain function according to the change amount of the tracking error Vte (S). Assuming that the function to be changed is T (S), the output Vtk (S) of the signal conversion unit 23 is expressed by Expression 12.

(Equation 12)

The transfer characteristic Gk (S) of the loop shown in FIG.
Is expressed by Expressions 13 and 14 from Expression 8.

(Equation 13)

[Equation 14]

The function T (S) of the signal conversion unit 23 is a DSP
(Digital Signal Processor) or the like, a feedback loop is established by changing the tracking error Vte (S) according to the change amount, that is, the change speed, of the tracking error Vte (S). Note that the tracking error Vte (S)
As the amount of change per unit time, the sampling time of the A / D converter or the like, or arbitrarily sampled data is used.

Next, a circuit block diagram of the present embodiment will be described with reference to FIG. Components in the figure having the same structure as in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. The error data SS1 obtained by converting the tracking error signal TE by the A / D converter 13 is supplied to the low-frequency boost unit 5 and the data change processing unit 24.

The result processed by the data change processing unit 24 is sent to the kick / brake signal generation unit 25 and changes the kick pulse or the brake pulse. There are 1) a pulse width, 2) a pulse voltage value, and 3) a number of pulses, which can be changed, and an optimum method for an optical system to be used may be used. Data change processor 24 and kick / brake signal generator 25
Is controlled by the controller unit 26.

The track jump control method of the present embodiment, including the control method, will be described with reference to the circuit block diagram of FIG. 12 and the timing chart of FIG. 14 according to the flowchart of FIG. 14A shows a tracking error signal TE, FIG. 14B shows an output signal of a kick / brake signal generator, and FIG. 14C shows a zero cross signal. Note that the kick / brake signal generation unit 25 performs the kick / brake signal generation by changing the pulse voltage value. In a track jump, acceleration and deceleration are repeated with respect to the movement speed of the actuator at a resonance frequency f0 or higher, and the actuator moves to a target track.

In step S301, the normal tracking servo is turned off by switching the switch 7 from the position N to the position J, and a kick signal of the level Vtk is supplied from the kick / brake signal generator 25 to the tracking actuator. To do.
As a result, the lens of the optical pickup starts moving, and the light beam starts track jump.

In step S302, the data change processing unit 24 calculates the speed by subtracting the current data da of the error data SS1 from the previous data db. In step S303, the data change processing unit 24 compares the speed obtained in step S302 with a predetermined speed, and
The kick signal Vtk is changed by the operation of FIG.

(Equation 15) Here, Ts is a conversion function according to the actuator operation sensitivity and characteristics.

In step S304, it is determined whether or not the tracking error signal TE is higher than a predetermined level Vth + by using the error data SS1. If it is higher, the process proceeds to step S305, and if it is lower, the process returns to step S302. In step S305, the output of the kick / brake signal generator 25 is held. This corresponds to ta in FIG.
This is because the vicinity of the point is a non-linear region, and it is necessary to perform another processing. The hold processing is performed when the tracking error signal TE reaches a non-linear region by another method, such as when the tracking error signal TE reaches a certain threshold level Vth and the amount of change in the tracking error signal waveform decreases. You may check after that.

In step S306, it is determined whether or not the tracking error signal TE is lower than a predetermined level Vth + by using the error data SS1. If lower, the process proceeds to step S307. If it is higher, the process returns to step S305 to continue holding the output of the kick / brake signal generator 25. In step S307, the same control as in step S302 is performed. In step S308, the same control as in step S303 is performed.
Since the polarity of the change of the tracking error signal waveform is inverted as shown in FIG.
It is necessary to change the polarity from 3.

In step S309, it is determined whether the tracking error signal TE has crossed zero. This decision
This is performed by changing the polarity of the zero cross signal SS2 output from the comparator 15 from the H level to the L level as shown in FIG. If zero crossing has occurred, the process proceeds to step S310, and if zero crossing has not occurred, the process returns to step S307. The determination of the zero cross may be made based on the error data SS1.

In step S310, the kick / brake signal generator 25 supplies a level-Vtk brake pulse. In addition, the timer 20 is reset, and the timer 20 starts time measurement. In step S311, the same processing as in step S302 is performed. In step S312, the same processing as in step S303 is performed, but the brake signal is changed.

In step S313, it is determined whether or not the tracking error signal TE is lower than a predetermined level Vth- using the error data SS1. If it is lower, the process proceeds to step S314, and if it is higher, the process returns to step S311. In step S314, the output of the kick / brake signal generator 25 is held. This corresponds to tb in FIG.
This is because the vicinity of the point is a non-linear area, so that it is necessary to perform another process, and this is the same as step S305.

In step S315, it is determined whether or not the tracking error signal TE is higher than a predetermined level Vth- by using the error data SS1. If higher, the process proceeds to step S316. If the value is lower, the process returns to step S314, and continues to hold the output of the kick / brake signal generator 25.

In step S316, step S311
The same process as is performed. In step S317, the same processing as in step S312 is performed. In step S318,
It is determined whether the time measured by the timer 20 is longer than a predetermined brake set time Tbj. If long, step S3
The process proceeds to step S320 if it is shorter. This is protection for when a zero crossing of the tracking error signal TE cannot be found in the next step S319 due to dust on the disk or the like.

In step S319, it is determined whether the tracking error signal TE has crossed zero. This decision
The polarity of the zero-cross signal SS2 output from the comparator 15 is changed from the L level to the H level as shown in FIG. If zero crossing has occurred, the process proceeds to step S320, and if zero crossing has not occurred, the process returns to step S316. The determination of the zero cross may be made based on the error data SS1.

In step S320, the switch is switched from position J to position N to return to normal tracking servo. This ends the track jump.

As described above, the actual lens speed for the track is obtained from the change in the tracking error signal TE, and the track jump is controlled by comparing the speed with the target speed. Therefore, an optimum track jump can be performed in consideration of a disc having a large surface deflection or warpage and a difference due to the structure of the optical pickup, and a stable and high-speed track jump can be realized.

<Fourth Embodiment> A fourth embodiment will be described with reference to FIGS. Components in the figure having the same structure as in the above example are denoted by the same reference numerals, and detailed description thereof will be omitted.

First, a block diagram of the transfer function will be described with reference to FIG. The tracking error Vte (S) output from the I / V conversion unit 4 is compared with the ROM (Read Onl
y Memory) 28. In the ROM 28, data of a target tracking error Vte (S) when the actuator model makes a track jump is stored for each sample sampled by the A / D converter. The comparison operation unit 27 compares the target data with the actual tracking error Vte (S) data, and outputs the result to the kick / brake signal generation unit 29.

The data stored in the ROM 28 may be not the tracking error itself but data relative to the immediately preceding data. FIG. 16 shows a circuit block diagram of the present embodiment. Comparison operation unit 27, ROM2
8. The kick / brake signal generator 29 is controlled by the controller 30.

The track jump control method of the present embodiment, including the control method, will be described with reference to the circuit block diagram of FIG. 16 along the flowchart of FIG.
In step S401, the normal tracking servo is turned off by switching the switch 7 from the position N to the position J, and the kick / brake signal generator 29 sends the level V to the tracking actuator.
tk kick pulse is supplied. This causes the lens of the optical pickup to start a track jump.

In step S402, the comparison operation unit 27 compares the error data SS1 with the target data stored in the ROM 28, and increases or decreases the output of the kick / brake signal generation unit 29 based on the result. That is, if the error data SS1 does not reach the target data, the output is performed so as to increase the lens speed, and if the error data SS1 exceeds the target data, the output is performed so as to decrease the lens speed.

In step S403, it is determined whether the tracking error signal TE has crossed zero. This decision
This is performed by changing the polarity of the zero cross signal SS2 output from the comparison unit 15 from the H level to the L level. If zero crossing has occurred, the process proceeds to step S404. If zero crossing has not occurred, the process returns to step S402. The determination of the zero cross may be made based on the error data SS1.

In step S404, the kick / brake signal generator 29 supplies a brake pulse of level -Vtk. In addition, the timer 20 is reset, and the timer 20 starts time measurement.

In step S405, step S402
, Except that the brake signal is changed. In step S406, it is determined whether the time measured by the timer 20 is longer than a predetermined brake set time Tbj. If longer, the process proceeds to step S408, and if shorter, the process proceeds to step S407. This is dust on the disk or the like. In the next step S407, the tracking error signal T
Protection for when the zero crossing of E is not found.

In step S407, it is determined whether the tracking error signal TE has crossed zero. This decision
This is performed by changing the polarity of the zero cross signal SS2 output from the comparison unit 15 from L level to H level. If zero crossing has occurred, the process proceeds to step S408, and if zero crossing has not occurred, the process returns to step S405. The determination of the zero cross may be made based on the error data SS1.

In step S408, the switch is switched from position J to position N to return to normal tracking servo. This ends the track jump.

As described above, by comparing the error data SS1 with the target data for each sample, it is determined whether the target is faster or slower than the target, and the track jump is controlled. Therefore, it is possible to perform an optimum track jump in consideration of a disc having a large surface deflection or warpage and a difference due to the structure of the optical pickup, thereby realizing a stable and high-speed track jump.

[0089]

According to the present invention, even if the disk has a large eccentricity, or the tracking pull-in after the track jump is poor due to the structure of the optical pickup, the optimum track jump taking into account the lens displacement and state can be performed. realizable. Such control enables a stable, high-speed, and reliable track jump.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of a first embodiment.

FIG. 2 is a control flowchart according to the first embodiment.

FIGS. 3A and 3B are timing charts of the first embodiment, wherein FIG. 3A shows a tracking error signal, FIG. 3B shows an output signal of a kick / brake pulse generator, and FIG.

FIG. 4 is a control flowchart of a second embodiment.

FIGS. 5A and 5B are timing charts of the second embodiment, in which FIG. 5A shows a tracking error signal, FIG. 5B shows an output signal of a kick / brake pulse generator, and FIG. 5C shows a zero cross signal.

FIG. 6 is a diagram illustrating a moving speed of a lens;
(A) is an output signal of the kick / brake pulse generator,
(B) is the moving speed of the lens.

FIG. 7 is a diagram of a vibration system model of an actuator.

8A and 8B are waveforms of a tracking error signal when crossing a track. FIG. 8A shows a three-beam method and a push-pull method.
(B) shows the case of the DPD method.

FIG. 9 is a block diagram of a transfer function of a servo loop.

FIG. 10 is a block diagram of a transfer function when a track jump is performed.

FIG. 11 is a block diagram of a transfer function according to the third embodiment.

FIG. 12 is a circuit block diagram of a third embodiment.

FIG. 13 is a control flowchart of the third embodiment.

FIGS. 14A and 14B are timing charts of the third embodiment, wherein FIG. 14A shows a tracking error signal, FIG. 14B shows an output signal of a kick / brake signal generation unit, and FIG. 14C shows a zero cross signal.

FIG. 15 is a block diagram of a transfer function according to the fourth embodiment.

FIG. 16 is a circuit block diagram of a fourth embodiment.

FIG. 17 is a control flowchart of the fourth embodiment.

FIG. 18 is a block diagram of a tracking servo.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Lens, 3 ... Light-receiving part, 4 ... I / V
Conversion section, 5: low-frequency boost section, 6: high-frequency phase compensation section, 7
... Switch, 8 ... Driver, 9 ... Optical pickup, 10
... Tracking actuator, 11 ... Kick / brake pulse generator, 12 ... Controller, 13 ... A / D
Converter, 14: Controller, 15: Comparison, 1
6 ... Kick / brake pulse generator, 17 ... Amplifier, 1
8 Adder, 19 D / A converter, 20 Timer, 21 Movable center, 22 Amplifier, 23 Signal converter, 24 Data change processor, 25 Kick / brake signal generator, 26 Controller section, 27: comparison operation section, 28: ROM, 29: kick / brake signal generation section, 30: controller section, TE: tracking error signal, SS1: error data, SS2: zero cross signal

Claims (6)

[Claims] 1. A track jump control device for causing a light beam to jump to an adjacent track from a state where the light beam follows a track of an optical disk, wherein a signal for generating a kick signal and a brake signal for moving the light beam A track jump control device comprising a generator, wherein the magnitude of the brake signal is changed based on a tracking error signal detected from the optical disc. 2. The track jump control device according to claim 1, wherein the magnitude of the kick signal is changed based on a tracking error signal detected from the optical disc. 3. A track jump control device for jumping the light beam to an adjacent track from a state where the light beam follows a track of the optical disk, wherein a signal for generating a kick signal and a brake signal for moving the light beam A track jump control device comprising a generator, wherein the magnitude of the brake signal is changed after a predetermined time from the start of supply of the brake signal. 4. The track jump control device according to claim 3, wherein the magnitude of the kick signal is changed a predetermined time after the start of the supply of the kick signal. 5. A track jump control device for causing a light beam to jump to an adjacent track from a state in which the light beam follows a track of an optical disk, wherein a signal for generating a kick signal and a brake signal for moving the light beam is provided. A track jump control device, comprising: a generator, wherein the kick signal and the brake signal are changed based on a change amount per unit time of a tracking error signal detected from the optical disc. 6. A track jump control device for jumping the light beam to an adjacent track from a state where the light beam follows a track of the optical disk, wherein a signal for generating a kick signal and a brake signal for moving the light beam A track jump control device comprising: a generator, wherein the kick signal and the brake signal are changed based on a result of a comparison operation between a tracking error signal detected from the optical disc and a target value of the tracking error signal. .