JPS63129573A - Controller for disk track position of high density recording medium - Google Patents

Abstract

PURPOSE:To speedily and stably jump a track by controlling the continuing time of a brake pulse following a kick pulse in a prescribed manner so as to vary at the time of jumping a track. CONSTITUTION:The kick pulse form a kick pulse generator circuit 13 is controlled by a jump control sequence circuit 12, and supplied to an adder 8 in a kick pulse servo control system. Then, when a zero cross detection circuit 11 detects the zero cross of a tracking error signal voltage, the brake pulse is generated from a brake pulse generator circuit 14, instead of the kick pulse, and supplied to the adder 8. A timer circuit 18 in response to a peak detection circuit 21, a brake pulse width control circuit 19, etc., control the circuit 14 to output the brake pulse whose width is variably controlled according to information showing the time when a track error signal reaches its peak. Due to the brake pulse with an appropriate width, a track is jumped speedily and stably.

Description

[Detailed Description of the Invention] [Industrial Application Fields] The present invention is directed to an information recording medium in which a beam is incident on an information signal recording surface of an information recording medium, a reflected return beam is detected,
Regarding an audio/video high-density recording and reproducing device that generates an electric signal and controls the focusing position of a beam incident on the information recording medium, in detail, the apparatus includes an information recording medium having different groove-shaped guide track pitches. The present invention relates to an information recording medium disk track position control device for a high-density recording device that allows stable track jumping operations even when the track jumping operation is stable.

[Prior Art] In recent years, development has been progressing to store digital information and video information on optical information recording media disks capable of high-density information recording, and to use them as large-capacity software playback memories.

A recording track is formed, and the storage track is optically injected with:
The following elemental technology has been developed as one of the important functions in high-density information recording and reproducing equipment equipped with an information recording medium disk having a recording surface for recording information. In other words, using a laser optical pickup imaging optical system, while controlling the focusing of the light beam spot for reading, the relative position of the light beam spot to the information track groove of the rotating disk consisting of the information recording medium is always accurately determined. There is a technology related to a tracking function that detects and performs follow-up control.

As a structure related to this tracking, FIG. 3 shows a conventional information recording medium reproducing apparatus, and in particular a tracking control apparatus for an optical information recording medium disk reproducing apparatus. In the figure, (1) is a track, (2) ) is a main spot which is a convergent light spot for reproducing signals from track (1), and (3) is a light beam placed before and after main spot (2) for obtaining track groove position control information on an information recording medium. A sub-spot which is a convergence spot, (4) is a reproduction signal amplifier for photoelectrically converting and amplifying the optical information into an electric signal after obtaining optical information, and (5) is a reproducing signal amplifier for obtaining optical information from the sub-spot (3). After obtaining the signal, photoelectrically convert it into an electrical signal,
An error signal generation differential amplifier (20) takes the signal difference and obtains a track error signal, and (20) is a track error signal which is the output of the error signal generation differential amplifier (5).
) is a servo signal amplifier that amplifies the track error signal,
(7) is a servo switch for turning on/off the output of the servo signal amplifier (6) and closing/opening the track servo control system, and (8) is for adding kick pulses and brake pulses to the servo switch output. Adder, (9) is a current amplifier that amplifies the output of adder (8), (10) is connected to current amplifier (9) and tracks (1) the main light spot (2) and sub-spot (3). a tracking actuator for movement in a direction perpendicular to the (11)
is connected to the error signal generation differential amplifier (5), and the positive and negative signals of the track error signal (20) are connected to the error signal generation differential amplifier (5). ] Zero cross detection circuit for detecting the voltage zero level, which is the turning point (1
2) is a jump control sequence circuit for generating opening/closing commands and track jump commands for the track servo control system; (13) is a jump control sequence circuit (12);
) is a kick pulse generation circuit for generating a kick pulse in response to a command, and (14) is a brake pulse generation circuit for generating a brake pulse in response to a command from a zero-cross detection circuit.

Next, the operation of the conventional example shown in - will be explained using FIG. In the above conventional recording and reproducing apparatus, in a normal reproducing state, the tracking information obtained from the sub-spot (3) becomes a track error signal (20) by the error signal generating differential amplifier (5), and this track error signal Tracking control is performed by (20).

That is, during this tracking control, the servo switch (7)
A command is issued from the jump control sequence circuit (12) to close the servo switch (7).

Therefore, the track error signal (20) is transmitted to the servo signal amplifier (6), the servo switch (7), the adder (8),
The current is applied to the tracking actuator (10) through a current amplifier (9). As a result, the tracking actuator (10) controls the main light convergence spot (2) to be located at the center of the track (1), and the reproduction signal amplifier (4) outputs an appropriate reproduction signal. It is something that can be ignored.

On the other hand, there may arise a need to instantly change the signal to be reproduced to that of an adjacent track, but in such a case, another control described below is performed.

This control operation is shown in Figure 4 (a), (b), (c).
This is explained by FIG. 4(a) is a sectional view of the information recording medium disk, FIG. 4(b) is a track error signal characteristic diagram, and FIG. 4(c) is a jump applied voltage characteristic diagram.

In the figure, (15) is the first information recording medium track currently being reproduced, (16) is the adjacent second information recording medium track to be reproduced next, and (17) is the first track. (15) and the second track (16) above.
It is a mirror surface sandwiched between. P is track pitch,
That is, the first track (15) and the second track (1
6) is the distance in the spot movement direction, and W is the width of the track (1) in the spot movement direction.

FIG. 4(b) shows that the sub spot (3) is located on the first track (
15), mirror surface (17), second track (1δ
) and in the direction perpendicular to the track (i.e. in the direction of the arrow in the figure)
0) Indicates voltage. FIG. 4(a) shows the first track (1
5) to the main spot (2) to the second track (16).
) shows the kick and brake pulses applied to the adder (8) to move the .

Next, FIG. 4(a) shows the operation of these signals.

This will be explained with reference to (b) and (c).

That is, when normal recording and reproduction are performed on the first track (15), the track error signal (20) voltage is at point A shown in FIG. 4(b).

When a kick pulse is applied to the servo system in this state, the track error signal (20) voltage waveform changes to A-B-+C-D as shown in FIG. (16) Track error signal obtained at the center (
20) The voltage settles at point D. As shown in Figure 4 (C), the jump applied voltage in this process is first the voltage value -V
K kick pulses are applied to the adder (8) and are maintained for a kick pulse generation time TK. This kick pulse duration TK is the position where the track error signal (20) voltage on the mirror surface (17) is zero volts, that is, the fourth
It is regulated at point B shown in the figure.

After this, the voltage applied to summing 2H(8) is inverted,
This results in a brake pulse having a voltage value VB, which is maintained for a time Tn. The duration To of the brake pulse is a constant predetermined value, for example, the track error signal (20) shown in FIG. 4(b).
It ends at the 0 point indicating the voltage. During the time TT (that is, expressed as Tk+TB) during which both the kick pulse and the brake pulse are generated, the track servo system is opened by the servo switch (7), but as shown in Fig. 4(b). It will be closed again at the 0 point shown in .

In this way, the track error signal (20) obtained at the 0 point shown in FIG. 4(b) attempts to draw the main spot (2) to the center of the second track (16),
The track error signal (20) voltage is changed to point D. In this way, a jump operation from the first track (15) to the second track (16) is performed.The operation on the circuit will be explained with reference to FIG. 3 again.

That is, a kick pulse starting command is issued by a jumping control sequence circuit (12), transmitted to a kick pulse generation circuit (13), adjusted to a desired voltage value, and added by an adder (8). The kick pulse input to the adder (8) is applied to the tracking actuator (10) via the current amplifier (9) to move the main light convergence spot (2) and the sub-spot (3).

On the other hand, this kick pulse start command information is also transmitted to the servo switch (7), giving a command to open the servo switch. As a result of the above, the servo control system is in an open state during the jumping period. The kick pulse start command information is also given to a zero cross detection circuit for detecting the positive/negative turning point of the voltage, and the zero cross immediately after the kick pulse start command of the track error signal (20) obtained when the servo control system is open. point, i.e., Fig. 4(b)
Point B shown in the characteristic diagram is obtained inside the zero-cross detection circuit (11).

The zero-crossing signal output from the zero-crossing detection circuit (11) indicating information regarding point B shown in FIG. 4(b) is first input to the jump control sequence circuit (12), , the jump control sequence circuit (12) transmits kick pulse end information to the kick pulse generation circuit (13). The kick pulse generation circuit (13) thereby stops applying the kick pulse to the adder (8). On the other hand, the zero-crossing signal is also applied to the brake pulse generation circuit (14), which generates a brake pulse for a brake pulse duration period TB with the zero-crossing signal as the starting point, and generates a brake pulse to the adder (8).
). This also applies a brake pulse to the tracking actuator. The end information of the brake pulse is also applied to the jump control sequence circuit (12), and provides the end information of the track servo system open time TT. As a result, the jump control sequence circuit (12
) gives a switch close command to the servo switch (7), and the servo system is closed again.

[Problems to be Solved by the Invention] Since the conventional information recording medium track position control device is configured as described above, it is difficult to perform a track search on a disc-shaped recording medium having a groove-shaped guide track. , when the track pitch P changes, the following problems occur. These problems are illustrated in Figures 5 (a) and (b).
) and (C), the tracking error signal voltage and jump applied voltage characteristic diagrams for the moving position of the light convergence spot will be used for explanation.

5(a), 5(b), and 5(c) show the case where the information recording medium track pitch P is expanded to Pw, or the point Cw in FIG. 5(b) indicating the end point of the brake pulse is Track error signal voltage [-1 Compared to FIG. 4(b), the position is different across the bottom position.

This is because the track error signal zero-crossing point B on the mirror surface (17) automatically moves as the track pitch P increases, and as a result, the kick pulse width TKν increases, but the brake pulse width TB remains constant. It is something that occurs because of something.

As mentioned above, since point 6w is separated from point D, which indicates the center of the second track (16), there is a problem that the track servo re-pulling time increases or the servo system becomes unstable. was there.

The present invention has been made in order to solve the above-mentioned problems, and provides an information recording medium track position control device for a recording device that can obtain a stable track jump operation in a short time even if the track pitch P is different. The purpose is to

[Means for solving the problems] The information recording medium track position control device according to the present invention has the following features:
Immediately after the track error signal voltage (20) passes through the zero cross characteristic point, which is the positive/negative turning point, on the mirror surface (17) with respect to the optical spot and the track position, and immediately after passing the voltage peak that appears for the first time, after a certain period of time has passed, The brake pulse is turned off to obtain a stable jumping operation that reliably responds to changes in track pitch.

[Function] The high-density information recording medium track position control device according to the present invention controls the brake pulse width using a peak detection circuit in the brake pulse width control circuit, and generates a brake pulse having an optimal duration for different track pitches. It has the effect of generating.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an information recording medium track position control device according to an embodiment of the present invention. In the figure, (18) is a track pitch detection circuit, and (19) is connected to the track pitch detection circuit (18). (21) is a peak detection circuit.

Hereinafter, in FIG. 1, the same or equivalent parts as in the conventional example shown in FIG. 3 are given the same reference numerals.

In the embodiment of the present invention, the peak detection circuit (21) detects the extreme peak of the track error signal (20).
This will be explained with reference to (c).

Figures 2(a), (b), and (c) are similar to Figure 4(a).
), (b), (c) and Fig. 5 (a), (b).

Similarly to (C), it shows the track error signal voltage characteristics and jump applied voltage characteristics when the recording/reproducing light spot moves across the track groove, but this peak detection circuit (
21), the track error signal (20) is transmitted to the mirror surface (
17), the zero crossing point which is the turning point of the signal, that is, the first extreme peak point F after passing point B shown in FIG. 2(b) is detected.

The peak F point information detected by such a peak detection circuit (21) is transmitted to the timer circuit (18). At this time, the timer circuit (18) is also sent the zero cross information on the mirror surface (17), that is, the information regarding point B shown in FIG. Time from signal to F point signal "BB"
is detected by the timer circuit (18). The output signal of the timer circuit (18) indicating such time Tl38 is:
It is input to the brake pulse width control circuit (19).

In the brake pulse width control circuit (19), this time TB
Based on the B information, the brake pulse width duration T13A after the peak F point is determined.

In this way, if the time "BB" from the B point signal detected by the timer circuit (18) to the peak F point signal is long, then the T[
The duration T of the brake pulse width determined by 3B
If B13 is longer and the time from point B to point F is shorter, the brake pulse width duration TDA will also be shorter.
A brake pulse width control time TDA is controlled. That is, the brake pulse width duration TDA is changed in accordance with the time TB13 from point B to point 0 shown in FIG. 2(b) so that the 0 point shown in FIG. 2(b) approaches the same point. It is something that makes you

As for the pulse with the duration width "BA," the end signal of the pulse with the duration width "BA" is extracted in the brake pulse width control circuit (19). The end signal of this pulse with a time width of 3 A is sent to the brake pulse generation circuit (14) and ends the duration of the brake pulse. This situation is illustrated by the jump applied voltage characteristics shown in FIG. As shown in the figure, the brake pulse width TBW varies from the positive/negative change zero-crossing point of the track error signal (i.e., point B shown in FIG. 2(b)) to the peak point that first appears following the zero-crossing point (see FIG. The brake pulse width duration TBA is added to the time up to point F shown in (b).

As described above, by means of ending the brake pulse after a certain period of time has passed after the peak point of the track error signal (20), the brake pulse ending point C is set to the second point as shown in FIG. 2(b). This corresponds to the vicinity of the center of the track (16).

Note that the peak detection circuit (21) receives commands from the jump control sequence circuit (12), detects unnecessary peaks, such as peaks in kick pulse duration, and prevents signal output. It is configured. The command for this is, for example, brake pulse width information, and the peak detection circuit ( 21) It constitutes a means.

Furthermore, a specific example of the peak detection circuit (21) described below is a voltage successive approximation circuit. That is, in the voltage successive approximation circuit, the track error signal (2o) is sampled at regular intervals and compared with the previous voltage value. In this way, when the comparison output between the previous value and the track error signal voltage (20) is viewed as a difference, the positive/negative No. 71 transition is detected, and when viewed as a ratio, the point at which it is reversed by comparing the magnitude with 1, etc. is detected as the peak point. It is something.

Further, the track jump direction is not necessarily limited to the direction of the arrow shown in FIG. 2(a), but may also be the direction opposite to the arrow.

In the case of a jump in the direction opposite to the direction of the arrow shown in FIG. Since the peak detection circuit (21) is configured so that the peak detection circuit (21) is inputted to the circuit (21) and inverts the output, the peak detection circuit (21) exhibits a detection effect similar to the case in the direction of the arrow shown in FIG. 2(a). .

Further, although the above embodiment shows an optical disc playback device using a 2-beam system for one type of track sensor, other track control devices using one type of track sensor may be similar to the above embodiment. It has the effect of Also,
The information recording medium reproducing device is not limited to an optical disc reproducing device, and may be a slanted disc reproducing device, which has the same effects as the above embodiment.

[Effects of the Invention] As explained above, according to the present invention, since the brake pulse width is varied by obtaining the extreme peak information of the track error signal voltage (20), the information of the high-density recording device is This has the effect that the tracking jump operation during tracking search in the recording medium disk track position control device can be performed quickly and stably.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a high-density information recording medium track position control device according to an embodiment of the present invention, and FIG. 2(a)
r (b) and (C) are characteristic diagrams showing the jump applied voltage characteristics during the track jump operation and the track error signal voltage characteristics with respect to the optical spot and track position according to the embodiment of the present invention, and FIG. A block diagram showing the information recording medium track position control device of FIG. 4(a), (
b) and (c) are characteristic diagrams showing a light spot for explaining a track jump operation, a jump applied voltage characteristic with respect to a track position, and a track error signal voltage characteristic;
Figures 5 (a), (b), and (c) show characteristics showing jump applied voltage characteristics and track error signal voltage characteristics with respect to optical spot and track position to explain problems in the conventional example during track jump operation. It is a diagram. (4) is a reproduction signal amplifier, (5) is an error signal generation differential amplifier, (6) is a servo signal amplifier, (7) is a servo switch, (8) is an adder, (9) is a current amplifier, (10)
) is a tracking actuator, (11) is a zero cross detection circuit, (12) is a jump control sequence circuit,
(13) is a kick pulse generation circuit, (14) is a brake pulse generation circuit, (18) is a timer circuit, (19) is a brake pulse width control circuit, and (21) is a peak detection circuit. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent Patent attorney Koshin Ookimi (and 2 others) Procedural amendment (voluntary) Showa - Month, Day

Claims (3)

[Claims] (1) A servo controller for a track search system that uses a sub-light spot to obtain a tracking error signal for a groove-type guide track of a high-density information recording medium to operate an actuator, and a kick pulse for a guide track jump and the above. A brake pulse following the kick pulse is generated, and the end point of the kick pulse duration is a zero cross point position where the track error signal on the mirror surface corresponding to the intermediate position between the first track and the second track turns positive and negative. In a high-density information recording medium disk track position control device in a recording apparatus equipped with a track jumping system configured to be regulated by A high-density information recording medium disk track position control device, characterized in that the brake pulse duration is controlled by the time to the extreme peak point of the track error signal voltage value. (2) A peak detection circuit for detecting the extreme peak of the voltage of the track error signal, and a timer circuit for measuring the time difference between the positive/negative change zero cross point time signal of the track error signal and the output signal of the extreme peak detection circuit. and the brake pulse width duration is determined based on the output signal of the timer circuit, and the brake pulse end signal is input to the brake pulse generation circuit. High-density information recording medium disk track position control device. (3) The high-density information recording medium disk track position control device according to claim 2, wherein the extreme peak detection operation time of the peak detection circuit is made equivalent to the brake pulse duration.