JPH0682470B2 - Information recording medium track position control device for recording device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an information recording medium reproducing apparatus, and in particular, a stable track jump operation can be obtained even if information recording media having different track pitches are arranged. The present invention relates to an information recording medium track position control device of a recording device.

[Prior Art] One of the important functions in a recorded information reproducing apparatus for a disc-shaped information recording medium for optically recording information is to perform a light-focused reading using a laser light pickup imaging optical system. There is a tracking function for controlling the light beam spot to follow the information track surface of a disc-shaped disc made of an information recording medium.

As a structure relating to this tracking, FIG. 3 shows a conventional information recording medium reproducing apparatus, particularly a tracking control apparatus of an optical information recording medium disc reproducing apparatus, in which (1) is a track and ( 2) is a main spot which is a converged light spot for reproducing a signal from the track (1), and (3) is a sub-spot which is a light spot for obtaining track control information before and after the main spot (2). , (4) is a reproduction signal amplifier for photoelectrically converting and amplifying the optical information into an electric signal after obtaining the optical information, and (5) is converting to an electric signal after obtaining the optical information from the sub-spot (3) Then, an error signal generation differential amplifier for obtaining the difference between them is obtained, (20) is a track error signal which is an output of the error signal generation differential amplifier (5), and (6) is a track error signal. A servo signal amplifier for amplifying the lock error signal, (7) a servo switch for turning on / off the output of the servo signal amplifier (6) to close / open the track servo control system, and (8) a kick to the servo switch output. An adder for adding pulses and brake pulses,
(9) is a current amplifier for amplifying the output of the adder (8),
(10) is a tracking actuator connected to the current amplifier (9) for moving the main spot (2) and the sub-spot (3) in a direction perpendicular to the track (1),
(11) is a zero cross detection circuit connected to the error signal generating differential amplifier (5) for detecting the voltage zero level of the track error signal (20), and (12) is an opening / closing command and a track jump command of the track servo system. A jump control sequence circuit for generating, (13) a kick pulse generation circuit for generating a kick pulse in response to a command from the jump control sequence circuit (12), and (14) a brake for receiving a command from a zero-cross detection circuit. It is a brake pulse generation circuit for generating a pulse.

Next, the operation of the above conventional example will be described with reference to FIG. In the recording / reproducing apparatus in the above-mentioned conventional example, the tracking information obtained from the sub-spot (3) becomes a track error signal (20) by the error signal generating differential amplifier (5) in the normal reproducing state, and this track error signal ( 2
Tracking control is performed by (0).

That is, at this time, a command is issued from the jump control sequence circuit (12) to close the servo switch (7), and the servo switch (7) is closed. Therefore, the track error signal (20) is applied to the tracking actuator (10) through the servo signal amplifier (6), the servo switch (7), the adder (8) and the current amplifier (9).
As a result, the tracking actuator (10) controls the main converging spot (2) to be located at the center of the track (1), and an appropriate reproduction signal is obtained from the reproduction signal amplifier (4).

On the other hand, it becomes necessary to instantaneously change the signal to be reproduced to that of the adjacent track. In such a case, another control described below is performed. This control operation is shown in FIG.
It will be explained with reference to b and c. 4a is a sectional view of the information recording medium disk, FIG. 4b is a trailer signal characteristic diagram, and FIG. 4c is a jump applied voltage characteristic diagram. (15) is the first track that is currently being played, (1
6) is the adjacent second track to be played next, (1
7) is a mirror surface sandwiched between the first track (15) and the second track (16). P is the track pitch, that is, the distance in the spot movement direction between the first track (15) and the second track (16), and W is the width in the spot movement direction of the track (1).

In Fig. 4b, the sub-spot (3) has the first track (1
5), the mirror surface (17), the second track (16), and the track error signal (20) voltage obtained when moving in the direction perpendicular to the track, that is, the direction of the arrow.

FIG. 4 (c) shows the kick and brake pulses applied to the adder (8) to move the main spot (2) from the first track (15) to the second track (16). Next, regarding the operation of these signals, FIG.
This will be explained with reference to c. When the normal reproduction is performed on the first track (15), the voltage of the track error signal (20) is at the point A shown in FIG. 4b. When a kick pulse is applied to the servo system in this state, the voltage waveform of the track error signal (20) is A → B → C → as shown in its characteristic in FIG. 4b.
It changes to D and stays at point D of the track error signal (20) voltage obtained at the center of the second track (16). As for the jump applied voltage in this process, a kick pulse having a voltage value −V _K is first applied to the adder (8) as shown in FIG.
It is maintained during the kick pulse generation period T _K. The kick pulse duration T _K is at the position where the voltage of the track error signal (20) on the mirror surface (17) is zero volt, that is, FIG. 4b.
It is regulated at point B shown in.

After this, the voltage applied to the adder (8) is inverted and becomes a brake pulse with a voltage value V _B, which is sustained for a period T _B. Brake pulse duration T
_B is a constant predetermined value, and ends at point C indicating the track error signal (20) voltage shown in FIG. 4b, for example. In the period T _T (that can be expressed as T _K + T _B ) in which both the kick pulse and the brake pulse are generated, the track servo system is opened by the servo switch (7), It will be closed again at point C shown in FIG. The track error signal (20) obtained at the point C tries to draw the main spot (2) into the center of the second track (16), and changes the voltage of the track error signal (20) to the point D. In this way, the jump operation from the first track (15) to the second track (16) is performed. The operation on the circuit will be described again with reference to FIG.

The kick pulse start command is issued from the jump control sequence circuit (12), sent to the kick pulse generation circuit (13), adjusted to a desired voltage value, and added to the adder (8). The kick pulse applied to the adder (8) is applied to the tracking actuator (10) via the current amplifier (9) to move the light converging main spot (2) and the sub-spot (3). On the other hand, the kick pulse start command information is also sent to the servo switch (7) to give a servo switch open command. As a result, the servo system is opened during the jump period. The kick pulse start command information is also given to the zero cross detection circuit, and the zero cross point immediately after the kick pulse start command of the track error signal (20) obtained when the servo system is open, that is, the point B shown in FIG. It is designed to be obtained in the detection circuit (11). The zero-cross signal which is the output of the zero-cross detection circuit (11) representing the point B information is first input to the jump control sequence circuit (12), and the jump control sequence circuit (12) receives this zero-cross signal and The kick pulse end information is given to the kick pulse generation circuit (13). In the kick pulse generation circuit (13), the application to the kick pulse adder (8) is stopped by this. On the other hand, the zero-cross signal is also applied to the brake pulse generating circuit (14), wherein the addition of the zero-crossing signal start points and the brake pulse duration T generated adder between brake pulses _B to (8). As a result, brake pulses are also applied to the tracking actuator. Brake pulse end information is jump control sequence circuit (12)
It also gives the end information of the track servo system open period T _T. This allows the jump control sequence circuit (1
A switch close command is given to the servo switch (7) from 2), 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, when the track pitch P changes, the following problems occur. These problems will be described with reference to the characteristic diagram of track error signal voltage and jump applied voltage with respect to the moving position of the light converging spot shown in FIGS.

FIGS. 5a, 5b, and 5c show the case where the track pitch P is widened to P _W , but the point C _W, which indicates the end point of the brake pulse, differs from the track error signal voltage in comparison with FIG. 4b. It is in a sick position. This is because the track error signal zero-cross point B on the mirror surface (17) automatically moves as the track pitch P increases, and as a result, the kick pulse width T _KW
However, it occurs because the brake pulse width T _B is constant. As described above, since the point C _W is separated from the point D indicating the center of the second track (16), there is a problem that the phenomenon of increasing the re-pull-in time of the track servo or the unstable operation phenomenon of the servo system is generated. there were.

The present invention has been made to solve the above problems, and provides an information recording medium track position control device for a recording device, which 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 Problems] An information recording medium track position control device in an audio recording device according to the present invention has means for detecting a change in the information recording medium track pitch, and a signal from the track pitch detecting means. On the basis of the above, the brake pulse width is automatically and variably controlled.

[Operation] The track position control device according to the present invention has means for detecting a change in the track pitch, such as an information recording medium track pitch detection circuit, in the brake pulse width control circuit included in the control device. It has the function of variably controlling the brake pulse width based on a signal from a circuit or the like to generate a brake pulse having an optimum duration for the track pitch.

EXAMPLES Examples 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). Brake pulse width detection circuit. In FIG. 1 below, the same or corresponding parts as those in the conventional example of FIG. 3 are designated by the same reference numerals. In the embodiment of the present invention, the track pitch detection circuit (18) uses the track pitch information instructed by the sequencer or the track pitch information calculated and detected from the voltage applied to the slide feed motor at the time of normal reproduction to determine the current track pitch information. Is transmitted to the brake pulse width control circuit (19). The brake pulse width control circuit (19) sets a desired pulse width according to the track pitch and gives a command to the brake pulse generation circuit (14). As a result, the brake pulse width corresponds to the track pitch. For example, the brake pulse width T _BW as shown in FIG. 2c is obtained, and as shown in FIGS. 2a and 2b, the brake pulse end point C point is obtained. Is near the center of the second track (16) with respect to the moving direction of the light converging spot.

In the above embodiment, the optical disc reproducing apparatus uses the two-beam method for the track sensor method, but the track control apparatus using another track sensor method also has the same operation as the above-mentioned embodiment. . Further, the information recording medium reproducing device is not limited to the optical information recording medium disc, and the needle type disc reproducing device has the same operation as that of the above embodiment.

As described above, according to the present invention, the track pitch information is obtained and the brake pulse width is variably controlled. Therefore, the track jumping operation at the track control position is performed quickly and stably. It is effective.

[Brief description of drawings]

FIG. 1 is a block diagram showing track position control of an information recording medium according to an embodiment of the present invention, and FIGS. 2A, 2B and 2C are jumps for a light spot and a track position during a track jump operation relating to the effect of the embodiment of the present invention. FIG. 3 is a characteristic diagram showing applied voltage characteristics and track error signal voltage characteristics. FIG. 3 is a block diagram showing a conventional information recording medium track position control device.
4A, 4B and 4C are characteristic diagrams showing a jump applied voltage characteristic and a track error signal voltage characteristic with respect to a light spot and a track position for explaining the track jump operation, and FIG.
FIGS. A, b, and c are characteristic diagrams showing jump applied voltage characteristics and track error signal voltage characteristics with respect to a light spot and a track position, for explaining problems in the conventional example at the time of the track jump operation. In the figure, (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 track pitch detection circuit, and (19) is a brake pulse width control circuit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] 1. A track servo system for obtaining a track error signal from a track of an information recording medium, a track servo system for amplifying the track error signal, and adding it to a tracking actuator for controlling a means for reproducing information from the track, and a track. A track control device having a kick pulse for jumping and means for generating a brake pulse subsequent to the kick pulse, and configured to add the generated brake pulse to the track servo system detects a difference in track pitch. And a brake pulse width control circuit that generates information for changing the width of the brake pulse by the output of the track pitch detection circuit, and the brake pulse width is changed by the output of the brake pulse width control circuit. And means for Information recording medium track position control apparatus of a recording apparatus characterized by. 2. Input information to a track pitch detection circuit,
The information recording medium track position control device of the recording device according to claim 1, wherein the track pitch information from the sequencer is used. 3. An information recording medium track position control device for a recording device according to claim 1, wherein the input information to the track pitch detection circuit is obtained from the applied voltage information of the slide feed motor.