JPH0736260B2 - Disk servo device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk servo device suitable for an optical disk reproducing device and the like, and more particularly to changing a track position of a pickup.

[Conventional technology]

As shown in FIG. 7, the optical disk reproducing device for reproducing information such as music recorded on a compact disk (CD), as shown in FIG. 7, has a focus servo that focuses on the reflective surface of CD2, and tracks the track of CD2. Tracking servo, constant linear velocity (C
Various servo devices such as LV) servos are installed, and these servo devices perform control operations according to the reflected light from the CD 2 and the read sync signal. The signal D _CLV applied to the motor 3 for rotating CD2 represents the drive output from the CLV servo system.

The pickup 4 is for reading the data recorded on the track of the CD 2 and detecting the track position.
The laser light 12 emitted from the laser light source 10 moved in the diameter direction of the CD 2 by the feed motor 8 via the arm 6 passes through the half mirror 14 called a beam splitter, and the optical system 16 such as an objective lens. Focused and CD
It is illuminated on the second reflective surface. Optical system 16 is focus coil 1
It is moved by 8 and the tracking coil 20, and the former focuses the reflective surface of the CD 2 and the latter moves it on the track.

Then, the reflected light 22 obtained from the CD2 is received by the light receiving section 24 composed of a plurality of light receiving diodes and is converted into an electric light receiving signal, which is added to the preamplification section 26, and an EFM signal or the like is added. The signal is separated into an RF signal including the signal, a focus error signal FE, and a tracking error signal TE, and the RF signal is output to a CLV servo system, an audio reproduction system, or the like.

The focus error signal FE is applied to the filter 28 in response to a focus search command FS from a control unit (not shown), the integrated output obtained by the filter 28 is applied to the driver 30, and the focus error signal FE is applied to the focus coil. 18 is driven and the optical system 16 is controlled to the just focus point.

Next, the tracking error signal TE is added to the filter 32 and integrated, and then the multiplexer (MPX) 34 is added to control the servo signal TS ₁ for controlling the tracking coil 20 and the feed motor 8. A feed servo signal TS ₂ for jumping over a plurality of tracks is formed. MPX34
Operates by a control signal from a control unit (not shown), and the MPX34 performs track jump control by a track jump signal Jp ⁺ and a track jump braking signal Jp ⁻ from the control unit.

Then, the servo signal TS ₁ obtained by the MPX34 is the driver 36
In addition, the drive signal output from the driver 36 drives the tracking coil 20. Further, the feed servo signal TS ₂ obtained by the MPX34 is integrated by the filter 38 to detect a direct current component, the direct current component is added to the driver 40, the motor 8 is driven by the output, and the pickup 4 is arbitrarily operated. Controlled by the track position.

[Problems to be solved by the invention]

By the way, when a plurality of tracks are skipped in such a reproducing apparatus, a pulse having a constant time τ _A is set as a track jump signal Jp ⁺ as shown in J of FIG. track jump brake signal Jp for stopping the track position ^- as shown in the Figure 8 as K, to set the track jump braking pulse of fixed time tau _B, also as shown in M of FIG. 8 The time τ _C of the arm feed signal SD for feeding the arm 6 is set at. The width of each time τ _A , τ _B , and τ _C is set to an approximate value by previously converting the number of interlaced tracks into time by a microcomputer.

Track jump signal Jp ⁺ and track jump braking signal J
p ^- time tau _A, the tau _B to draw the end at the same time the servo operation of the track jump, the period during which the track jump is being performed, as shown in N of FIG. 8, the gain up time The gain of the servo system is increased by the gain-up pulse having the time width τ _D that represents the time period τ _D , and the servo operation is canceled for the time (τ _A + τ _B ), as indicated by O in FIG. Further, L in FIG. 8 is a synchronization confirmation signal GFS indicating that the synchronization state is obtained in response to the start of the servo operation, and the gain shown in N in FIG. 8 is indicated in accordance with the synchronization confirmation signal GFS. Up pulse is released.

Then, various times τ _A , τ _B , τ _C , τ _D of the track jump signal Jp ⁺ and the like are determined by a substantial method in relation to the mechanical mechanism such as the tracking mechanism and the feed mechanism of the pickup 4, Since it is necessary to empirically set each mechanism of the device and the time cannot be precisely set, the control becomes rough, and if the matching with the mechanism cannot be obtained, malfunction may occur.

Therefore, the present invention is intended to realize the proper track jumping regardless of the mechanical mechanism by counting the number of track jumps from the tracking error signal to grasp the situation of the track jumps.

[Means for solving problems]

As shown in FIG. 1, the disk servo apparatus of the present invention is a disk servo apparatus for controlling a pickup to a track position of a disk, and a tracking error detecting means (calculation unit) for detecting a tracking error from a detection signal of the pickup. When the track jump is started in response to the amplifier 48) and the track jump command (track jump command signal T _JO ), the number of jump tracks is calculated based on the tracking error signal detected by the tracking error detection means. When the track jump continues while counting, and when the number of tracks reaches a set number, the track jump is braked, and at that time, the zero-cross signal of the obtained tracking error signal becomes less than the reference time. , A track jump control means for ending the track jump ( And a track jump control unit 56).

[Action]

The track jumping control means responds to the track jumping command (track jumping command signal T _JO ) with the track jumping signal J.
generate p ⁺ . Depending on this track jump signal Jp ⁺ ,
The pickup 4 moves in an arbitrary track direction of the disc. When a track jump occurs, a tracking error signal TE corresponding to the track jump is obtained from the tracking error detecting means. Then, the track jump control means counts the tracking error signal TE obtained by the tracking error detection means, performs the track jump drive until the jump track number reaches a specific value, and brakes according to the track jump number. The movement of the pickup 4 is promptly stopped, and the jumping of a plurality of tracks is completed.

〔Example〕

FIG. 1 shows an embodiment of the disk servo device of the present invention.

This embodiment is a case of using a pickup by the three-beam method in which a main beam is projected to the center of the track and a sub beam is projected to a position slightly deviated to the left and right from the track of the CD2 track.

Photodetectors 42, 44 and 46 are installed in the light receiving section 24 of the pickup 4 in accordance with the number of beams, and each of the photodetectors 42, 44 and 46 is composed of, for example, a light receiving diode. The photodetector 42 is the main beam MB, and the photodetectors 44 and 46 are the sub-beams SB ₁ and SB _2.
And the detection output RF of the main beam MB of the photodetector 42 is added to an audio system (not shown).
The detection signals Va and Vb obtained in step 3 are added to the operational amplifier 48 installed as tracking error detecting means for detecting a tracking error, and the tracking error signal TE is detected.

By the way, the main beam MB and the sub-beams SB ₁ and SB ₂ are
As shown in (b) of the figure, when the main beam MB is aligned with the pit P of the track, the sub beams SB ₁ and SB ₂ are
It is set so as to be shifted from the pit P to the left and right, and the shift widths are equal. 2A shows the case where the main beam MB is displaced to the left, and FIG. 2C shows the case where the main beam MB is displaced to the right, and O is the center line of the on-track position. , O'represents a center line when they are shifted to the left and right. The tracking error signal TE obtained by the operational amplifier 48, when the main beam MB coincides with the track, has an amplitude corresponding to the deviation direction and the deviation width, as shown in FIG. It is given by an S-shaped signal having positive and negative amplitudes with the position at the zero level.

The tracking error signal TE is applied to the filter circuit 50 including a low-pass filter and converted into a DC signal, and then applied to the driver 36 via the switch 52. The switch 52 is installed to shut off the servo system during a track jump, and is closed during tracking control other than the track jump.

The driver 36 generates a drive signal corresponding to the tracking error signal TE and drives the tracking coil 20. That is, the tracking coil 20 changes the excitation degree and the excitation direction according to the tracking error signal TE, and generates a driving force that pulls back to the left in the case of right shift and to the right in the case of left shift. . Therefore, the pickup 4 is controlled on the track by the tracking control.

Then, the zero-cross detection circuit 54 crosses the zero level of the tracking error signal TE to generate a signal corresponding to the positive-side signal component, for example, a zero-cross pulse TZC, and applies it to the track jump control unit 56. Truck jump control unit
Reference numeral 56 is a control device such as a microcomputer mounted on the optical disk reproducing device, or is configured as an independent circuit, and performs track jump control according to the track jump command signal T _JO . That is, the track jump command signal T _JO
Is added to the track jump control unit 56, the track jump control unit 56 shifts to the operating state and enters the track jump mode, and the servo release signal S _B and the track jump signal Jp ⁺
And after generating a gain control signal Gc, track jump brake signal Jp ^- outputting a.

The switch 52 is switched to the cutoff state by the servo release signal S _B , the servo system is cut off, and the normal servo control is released.

The track jump signal Jp ⁺ has a signal mode corresponding to the track jump direction and is designated by the track jump instruction. This track jump signal Jp ⁺ is a driver 36
In addition, the tracking coil 20 is forcibly excited for the track jump, and the pickup 4 moves in the desired track direction. At this time, the driver 36 is set to, for example, the maximum gain by the gain control signal Gc in order to shift to the normal control state when the track jump is released.

When the pickup 4 moves between tracks, the movement causes a tracking error signal TE as shown in FIG.
Zero crossing signal TZ of tracking error signal TE
Ask for C. Reference time τa of this zero-cross signal TZC
Since a signal having a time width that exceeds the value corresponds to the true tracking error signal TE, this is counted, and the track jump signal Jp ⁺ is continuously output until the count value reaches the set value, and the track jump signal is continued. Similarly to the end of the signal Jp ⁺ , the track jump braking signal Jp ^- is issued. Track jump braking signal J
p ⁻ is output until the time of the zero-cross signal TZC exceeds the reference time τa, and the track jump ends. At the end of this track jump, switch 52 is closed, servo control is restarted, and the gain control signal
Gc is released and control operation is performed with normal gain.

Therefore, in this disk servo device, the track jump is started by the track jump signal Jp ⁺ , and the pulses exceeding the reference time τa of the zero-cross signal TZC of the tracking error signal TE obtained thereby are counted up to the set jump track number. At the same time, the track jump signal Jp ⁺ is maintained until the counting end time, the track jump braking signal Jp ⁻ is generated from the counting end time, and the track jump braking signal Jp ^{− is set} to the zero time signal JZC as the reference time τ.
Continues until a is exceeded and finishes track jumping of multiple tracks. For this reason, a braking signal according to the mechanical characteristics of the tracking mechanism is obtained, so that it is not necessary to make adjustments in consideration of the characteristics of individual tracking mechanisms. Also,
The track jump time can be optimized according to the levels of the track jump signal and the braking signal, and the inter-track movement can be performed quickly and without malfunction.

Next, FIG. 4 shows a specific configuration example of the track jump control unit 56 of the disk servo device shown in FIG. In this configuration example, both a single track jump and a plurality of track jumps can be performed, the switch 57 is switched according to the number of jump tracks, and X is one track jump, Y is closed in case of jumping over two or more tracks.

The track jump instruction signal T _JO is given by the step signal and is applied as a negative input to the NAND circuit 58 which constitutes the inhibition circuit. The NAND circuit 58 is set to H by the logical product of the inverted signal of the track jump command signal T _JO , the non-inverted output Q of the flip-flop circuit 60 installed as the state storage means, and the track jump braking signal Jp-.
Generates a (high) output, and outputs that output to a flip-flop circuit
Add as D input to 60.

The non-inverted output Q of the flip-flop circuit 60 is the NAND circuit 62.
And the inverting input of its non-inverting output Q and the output of the OR circuit 64 are ANDed. The H output of the NAND circuit 62 is the D of a flip-flop circuit 66 provided as state storage means and means for generating the track jump signal Jp ^+.
Added to input. When the H output is applied from the NAND circuit 62, the flip-flop circuit 66 outputs the track jump signal Jp ⁺ as its non-inverted output Q and applies it to the NAND circuit 68. The NAND circuit 68 takes the logical product of the inverted signal of the track jump signal Jp ⁺ and the count output of the counter 70 obtained via the switch 57 or the comparison output V ₂ of the comparator 71,
Its H state storage means output and track interlaced brake signal Jp ^- are added to the D input of the flip-flop circuit 72 which is installed as a generating means. When the H output is generated from the NAND circuit 68, the flip-flop circuit 72 generates the track jump braking signal Jp ⁻ as the non-inverted output Q. And
The non-inverted output Q of the flip-flop circuits 66 and 72 is connected to the AND circuit 7
In addition to 4, the servo release signal S _B is formed by the logical product of both.

The counter 76 and the comparator 71 are installed as signal determining means for determining whether or not the signal is a true zero-cross signal TZC. That is, the counter 76 is
It is a means for measuring the time width of TZC, and the non-inverted output Q of the flip-flop circuit 60 is added as an initial setting signal CL, and the zero-cross signal TZC is added as a count control signal indicating the start and end of counting the clock pulse CLK. So clock pulse C time zero crossing signal TZC
Output with the count value N ₁ of LK. This count value N ₁ output is applied to the comparator 71 and compared with the reference time τa for determining whether or not the true zero-cross signal TZC is present. Comparator 71
Generates a comparative output V ₁ when τa <N ₁ and a comparative output V ₂ when τa> N ₁ .

The comparison output V ₁ is applied to the counter 80 as a count drive signal, and upon arrival of the comparison output V ₁ , the counter 80 starts counting clock pulses CLK. The counter 80 is installed as time setting means for setting the time of the track jump signal Jp ⁺ , and the non-inverted output Q is added from the flip-flop circuit 60 as the initial setting signal CL, and
The zero-cross signal TZC is added as a count control signal indicating the start and end of counting of the clock pulse CLK, and the count value N ₁ corresponding to the reference time τa is used as an initial value until the zero-cross signal TZC shifts to a low (L) level. Count. This count value N ₂ represents the time of the zero-cross signal TZC.

This count value N ₂ is added to a shifter 82 as a counting and multiplying means installed as a time setting means for setting the time of the track jump braking signal Jp ⁻ , and a coefficient k for obtaining an optimum braking time is obtained. _{They are} multiplied together and the multiplication result is k · N ₂
Is set in the counter 70. The counter 70 is a time setting means for setting the braking time as a real time, and the non-inverted output Q from the flip-flop circuit 60 is added as an initial setting signal CL and a clock pulse is added.
CLK is added, and the set value k · N ₂ from the shifter 82 is incremented and output by counting the clock pulse CLK, and the counting time is added to the NAND circuit 68. Counter 70
May be composed of, for example, a register.

Further, the zero cross signal TZC is added to a counter 84 installed as a counting means for counting a plurality of jumping tracks, and the count value M and the set number added by the initial setting.
M ₀ is compared with the comparator 86. The comparison output of the comparator 86 and the comparison output V of the comparator 71
₂ is ANDed by the AND circuit 88. Along with the output of the AND circuit 88, the comparison output V ₁ of the comparator 71 is the OR circuit.
It is added to 64 and becomes a logic input of the NAND circuit 62.

The generation of the track jump signal Jp ⁺ and the track jump braking signal Jp ^{− in} the above configuration will be described with reference to the flowchart shown in FIG. 5 and the timing chart of FIG.

When jumping over a plurality of tracks, the switch 57 is closed to the Y side.

In FIG. 5, the tracking servo operation is started, and it is determined in step S ₁ whether there is a track jump command signal T _JO for jumping over a plurality of tracks. If there is no track jump command signal T _JO , step S ₁
The determination of is repeated until the track jump command signal T _JO arrives.

When the track jump instruction signal T _JO is determined to have arrived, with the process proceeds to step S _2, initializes the counters 70,76,80,84, flip-flop circuits 60 and 66,
Set the initial value input IR to the reset input R of 72.

Then, the process proceeds to step S _3, AND condition of the AND circuit 74 outputs the servo release signal S _B satisfied. As a result, the switch
52 is opened and the servo loop is released.

Then, the process proceeds to step S _4, the track jump instruction signal T
_{Since JO} is given at H level, the NAND circuit 58 becomes L output and the non-inverted output Q of the flip-flop circuit 60 becomes L output. Since the output of the OR circuit 64 is the H output,
The NAND condition of the NAND circuit 62 is established, its H output is added to the D input of the flip-flop circuit 66, and the flip-flop circuit 66 outputs the non-inverted output Q as the track jump signal Jp as shown in C of FIG. Output ⁺ .

The pickup 4 moves between the tracks due to the track jump signal Jp ⁺ , but the movement causes a signal including the tracking error signal TE from the operational amplifier 48 shown in FIG. 1 to A shown in FIG. can get. These signals are applied to the zero-cross detection circuit 54, and the zero-cross detection circuit 54 obtains the zero-cross signal TZC shown in FIG. 6B as a signal corresponding to the signal component exceeding the zero level.

Next, in step S ₅ , in the comparator 71, the count value N ₁ of the counter 76 is compared with the reference time width τa, and the count value
If N ₁ is larger than the reference time width τa (τa <N ₁ ), the process returns to step S ₃ , and the servo release signal S _B is continuously output to maintain the release of the servo loop. When the count value N ₁ is smaller than the reference time width τa (τa> N ₁ ), the process proceeds to step S ₆ and the count value M of the counter 84 and the set value M ₀ are compared by the comparator 86. If M <M ₀ , the process returns to step S ₃ , and the servo release signal S _B is continuously output to maintain the release of the servo loop. If M <M ₀ is not satisfied, the step
Proceeds to S _7, a track jump signal Jp ⁺ with releasing the track interlaced braking signal as shown in D of FIG. 6 Jp
^-Is output.

The track jumping braking signal Jp ^- causes the track jumping to enter the braking state, and in the braking state, the step
It goes to S _8, and compares the count value N ₁ and the reference time counter 76 .tau.a comparator 71. If τa <N ₁ , step
Returns to S _7, track interlaced braking signal Jp ^- continue to put out a, τ
If a> N _1, the process proceeds to step S ₉ to release the track jump braking signal Jp ⁻ and end the track jump.

For track jump, for example, when a jump command signal T _JO between a plurality of tracks arrives, the servo loop is canceled during the track jump as shown by I in FIG. 6, and C in FIG. Track jump signal as shown in
Issue Jp ⁺ and zero cross signal T by true track jump
In order to detect ZC, the reference time width τa is set, and the arrival of a pulse exceeding the reference time width τa of the zero-cross signal TZC shown in FIG. 6B is waited for. Then, the zero-cross signal TZC exceeding the reference time τa is counted, the count value M is compared with the set value M _0, and the track jump signal is reached until M = M ₀ is reached.
Keep issuing Jp ⁺ . When M = M ₀ , the track jump signal Jp ⁺ is released, and at the same time, the track jump braking signal Jp ⁻ shown in D of FIG. 6 is generated until the zero-cross signal TZC reaches the reference time τa. track interlaced braking signal Jp ^- the continuing out.

E in FIG. 6 represents the first arm feed signal SD ₁ , and F in FIG. 6 represents the _second arm feed signal SD ₂ , and each arm feed signal SD ₁ , SD ₂ is shown in FIG. 7. The signal representing the scanning period of the pickup 4 by the arm 6 includes, for example, 10
Select the arm feed signal SD ₁ for track jump signals Jp ⁺ up to 0 tracks and the arm feed signal SD ₂ for track jump signals Jp ⁺ over 100 tracks, depending on the number of track jumps. The feed motor 8 is driven. It should be noted that these signals SD ₁ and SD ₂ are selected according to the device or the width thereof is adjusted, and further, the fine adjustment is performed by adding or decreasing the set value of the register for setting the servo signal. I shall.

Further, G in FIG. 6 represents a section in which the gain of the servo system is increased at the same time as the end of the track jump, and the gain increase is that the arrival of the frame synchronization signal N times or the error correction flag is released. Shall be canceled. For example, as shown in FIG. 6H, the synchronization confirmation signal GFS
To get Since the servo gain rise period is easily affected by disturbance, the gain rise period is set until this synchronization confirmation signal GFS is continuously obtained, and the gain increase of the servo loop is canceled by the arrival of the regular synchronization confirmation signal GFS. Then, by returning the servo gain to the gain during normal reproduction, the servo operation is stabilized and reproduction is performed.

Next, when jumping over one track, set switch 58 to X.
Close to the side.

In this case, the counter 80 is started, the clock pulse CLK is counted, the zero-cross signal T
When it is determined that there is no ZC, the counting is stopped. The count value N ₂ of the counter 80 represents the time of the zero-cross signal TZC. The count value N ₂ of the counter 80 is multiplied by the coefficient k (= 1 / n) by the shifter 82 to obtain a coefficient value k · N ₂ (<N ₂ ). Next, the count value k · N ₂ is set in the counter 70, and the track jump braking signal Jp ⁻ for one track is output.

Next, the count set value k · N ₂ of the counter 70 is clock pulsed.
Increment by counting CLK and set count value kN
_It is determined whether ₂ has become 0 or not. Count set value k ・ N
_2, the track jump braking signal when the 1-track jump Jp ^- represents the time width. When the count setting value k · N ₂ is not 0, the track jump braking signal Jp ⁻ is continuously output, and when the count setting value k · N ₂ is 0, the track jump braking signal Jp ⁻ is released. Finish jumping one track.

〔The invention's effect〕

According to the present invention, the track jumping signal is started by the track jumping signal, the tracking error signal obtained thereby is counted, and when the count value reaches the set value, the track jumping signal is canceled and the track jumping signal is released. Since a jumping braking signal is generated and track jumping is ended, it is possible to quantitatively jump to any track, and it is possible to respond to the mechanical characteristics of the tracking mechanism, and add the characteristics of individual tracking mechanisms. Adjustment is unnecessary, and the time of track jump can be optimized according to the levels of the track jump signal and the braking signal, and the movement between tracks can be performed quickly and without malfunction.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a disk servo device of the present invention, FIG. 2 is a diagram showing tracking errors, and FIG. 3 is a tracking error signal obtained based on the tracking errors shown in FIG. Shown in Figure 4, Figure 1 is
FIG. 5 is a block diagram showing a specific configuration of the track jump control unit shown in FIG. 5, FIG. 5 is a flowchart showing the track jump control, FIG. 6 is a timing chart showing the track jump control, and FIG. 7 is an optical disk reproduction. FIG. 8 is a diagram showing a conventional disk servo device in the apparatus, and FIG. 8 is a timing chart showing track jumping in the disk servo device shown in FIG. 2 …… CD (disk) 4 …… Pickup 48 …… Operational amplifier (tracking error detection means) 56 …… Track jump control section (track jump control means)

Claims (1)

[Claims] 1. A disk servo device for controlling a pickup to a track position on a disk, wherein tracking error detection means for detecting a tracking error from a detection signal of the pickup and track jump start in response to a track jump command. When, the number of jumping tracks is counted based on the tracking error signal detected by the tracking error detecting means and the track jumping is continued, and when the track number reaches a set number, the track jumping is performed. When the zero-cross signal of the tracking error signal obtained is below the reference time,
A disk servo apparatus, comprising: a track jump control means for ending the track jump.