JPH01176332A - Cross track number counting device - Google Patents

Abstract

PURPOSE:To exactly count the number of tracks over which a beam crosses by starting the counting of the number of crossing tracks after a prescribed time passes over and a tight seek or the rise of a track jump commanding signal. CONSTITUTION:A counter 10 starts the count of a binarizing signal when the prescribed time passes over after the tight seek or the rise of a track jump commanding signal A. Thus, even when a track error signal is almost '0' at the time of tracking control, the number of the cross tracks is not erroneously detected in case that control is switched from tracking control to tightly seek or track jump control. Even when an objective lens is caused to jump from the final sector of the track to the first track of the track so that the beam can continuously follow one track, erroneous detection is not executed by a pre-bit. Thus, the number of the tracks over which the beam crosses can be exactly counted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a transverse track number counting device used in optical disk devices and the like.

BACKGROUND ART FIG. 2 shows a conventional crossing trunk number counting device, in which 1 is an optical disk as a recording medium, 2 is a spindle motor that rotates the optical disk 1, 3 is a device for writing data, etc. on the optical disk 1, Further, an optical pickup 4 for reading data etc. written on the optical disk 1 outputs a sinusoidal tracking error signal indicating the positional deviation of the beam with respect to the track of the optical disk 1 based on the output of the light receiving element of the optical pickup 3. The dynamic amplifier 5 is a switch that is turned on when the beam is tracking and turned off when the beam closely seeks or jumps between tracks.
6 is a phase compensation circuit that stabilizes the tracking error signal from the differential amplifier 4; 7 is a drive for an optical pink-up 30 objective lens so that the signal from the phase compensation circuit 6 or a switch 11 (described later) becomes rOJ; This is a driver that

These objective lens, differential amplifier 4, switch 5, phase compensation circuit 6, and driver 7 constitute a servo loop during tracking, and the driver output is set so that the trunk error signal from the phase compensation circuit 6 becomes "0". , optical pickup 3
The beam is controlled to follow the track of the optical disc 1 by driving the objective lens.

8 is a speed detection circuit that detects the relative speed of the objective lens with respect to the trunk based on the track error signal from the differential amplifier 4; 12 is a binarization circuit that binarizes the trunk error signal from the differential amplifier 4; It is a circuit.

1o outputs the command speed of the objective lens according to the seek amount to the command speed circuit 9 when a close seek or track jump command and a seek amount command are input, and also turns off the switch 5 and turns off the switch 11. A counter 8a counts the number of times the tracking error signal becomes "0" level due to the signal from the binarization circuit 12. This is a subtracter that subtracts the speed and outputs it to the driver 7 via the switch 11.

Next, the operation of the above conventional example will be explained.

In FIG. 2, when the counter 10 receives a close seek or track jump command signal and a seek amount command,
The number of tracks is set according to the seek amount, and by turning off the switch 6 and turning on the switch 11, the above-mentioned tracking servo loop is switched to fine seek or track jump control, and the command speed is set according to the seek amount. At the same time as outputting to the command speed circuit 9, counting of the signal from the binarization circuit 12 is started.

Next, the difference between the commanded speed and the actual speed of the objective lens is input from the subtracter 13 to the driver 7 via the switch 11, and the driver outputs the signal so that this input signal becomes "o".
By driving the objective lens of the optical pickup 30, the beam is controlled to traverse between the tracks of the optical disc 1.

The counter 10 counts the number of times the track error signal reaches the rOJ level, and when the set number of tracks is reached, the switch 6 is turned on and the switch 11 is turned off to switch from close seek or track jump control to tracking control. .

Problems to be Solved by the Invention However, in the above-mentioned conventional crossing truck number counting device, the counter 10 starts counting the number of crossing trunks at the rising edge of the close seek or track jump command signal, and the tracking error signal is not output during tracking control. Since it is approximately at the "o" level, there is a problem in that the counter 10 makes a false detection when switching from tracking control to close seek or trunk jump control.

In particular, when the objective lens jumps from the last sector of a track to the first track of that track (stay jump control) so that the beam follows one track continuously, there is a problem of false detection due to prefocusing. There is a point.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a transverse track number counting device that can accurately count the number of tracks that a beam traverses. Alternatively, counting of the number of crossing trucks is started after a predetermined time has elapsed after the rise of the trunk jump command signal.

Effect of the Invention With the above configuration, the present invention does not start counting immediately when switching from tracking control to dense seek or track jump control, so it is possible to accurately count the number of trunks traversed by the beam.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1(a) is a block diagram showing an embodiment of the crossing track number counting device according to the present invention, and FIG.
3 is a timing chart showing main signals in the transverse track number counting device of (b), in which the same components as those shown in FIG. 2 are given the same reference numerals.

In FIG. 1(a), numeral 1 is an optical disk that is a recording medium, and the optical disk 1 has concentric or spiral tracks that serve as recording areas.

2 is a spindle motor for rotating the optical disc 1; 3 is an optical pickup for writing data, etc. on the optical disc 1, and reading data, etc. written on the optical disc 1;

The optical pickup 3 is movable in the radial direction of the optical disk 10, and also includes a semiconductor laser (not shown) that generates a beam, and an objective lens (not shown) that focuses the beam from the semiconductor laser and irradiates it onto the optical disk 1. ), an element for receiving reflected light from the optical disc 1, etc., and the objective lens can be moved minutely in the radial direction of the optical disc 1 for beam tracking, dense seek between tracks, and jump.

4 is a differential amplifier that outputs a sinusoidal tracking error signal indicating the positional deviation of the beam with respect to the track based on the output of the light-receiving element of the optical pickup 3; 6 is turned on during beam tracking, and the beam moves closely between tracks; Switch 6 is turned off when seeking or jumping.
A phase compensation circuit 7 stabilizes the tracking error signal from the differential amplifier 4, and a driver 7 drives the objective lens of the optical pickup 30 so that a signal from the phase compensation circuit 6 or a switch 11 (described later) becomes "0". It is.

These objective lens, differential amplifier 4, switch 6, phase compensation circuit 6, and driver 7 constitute a servo loop during tracking, and the driver 7 controls the tracking error signal from the phase compensation circuit 6 to be "o". The objective lens of the optical pickup 3 is driven, and as a result, the beam is directed toward the optical disk 1.
control to follow the track of.

8 is a speed detection circuit that detects the relative speed of the objective lens with respect to the track based on the track error signal from the differential amplifier 4; 12 is a binarization circuit that binarizes the track error signal from the differential amplifier 4; It is a circuit.

13, the rise of the command signal A for a close seek or track jump as shown in the upper part of FIG.
A time constant circuit 14 that delays about 0 μS masks the signal from the binarization circuit 12 as shown in the lower part of FIG. The AND gate 15 that generates the signal B is an AND gate that masks the signal from the binarization circuit 12 with the mask signal B.

10 outputs a command speed of the objective lens according to the seek amount to the command speed circuit 9 when a close seek or track jump command and a seek amount command are input, and also turns off the switch 6 and turns off the switch 11. Turn on and AND
a counter 13 for counting the number of times the track error signal becomes "o" level due to the binary signal from the gate 16;
is the speed detection circuit 8 based on the command speed from the command speed circuit 9.
This is a subtracter that subtracts the current speed detected by and outputs the result to the driver T via the switch 11.

Next, the operation of the embodiment according to the above configuration will be explained.

In FIG. 1, when a close seek or track jump command signal A and a seek amount command are input to the counter 1o, the number of tracks corresponding to the seek amount is set, and the switch 5 is turned off and the switch 11 is turned on. As a result, the above-described tracking servo loop is switched to fine seek or track jump control, and a command speed corresponding to the seek amount is output to the command speed circuit 9.

Next, the difference between the commanded speed and the actual speed of the objective lens is input from the subtracter 13 to the driver 7 via the switch 11, and the driver 7 controls the optical pickup 30 objective lens so that this input signal becomes "0". As a result, the beam is controlled to cross between the tracks of the optical disc 1.

On the other hand, the command signal A for close seek or track jump is
The signal delayed by the time constant circuit 13 and thus from the binarized signal is input to the counter 1o after this delay time by the AND gate 14.16.

The counter 10 counts the number of times the track error signal reaches the rOJ level by counting this binary signal, and when the set number of tracks is reached, the switch 6
is turned on and the switch 11 is turned off to switch from close seek or track jump control to tracking control.

Therefore, according to the above embodiment, the counter 1o starts counting the binarized signal after a predetermined period of time has elapsed after the rise of the command signal A for close seek or track jump.
Even at the "o" level, the number of traversed tracks will not be erroneously detected when switching from tracking control to dense seek or track jump control.

Also, when the objective lens jumps from the last sector of a trunk to the first trunk of that track (stale jump control) so that the beam follows one track continuously, false detection can occur due to prepits. do not have.

As described in detail, the present invention starts counting the number of trunks crossed after a predetermined time elapses after the close seek or track jump command signal Ω rises, so it is possible to accurately count the number of trunks crossed by the beam. can be counted.

[Brief explanation of the drawing]

FIG. 1(a) is a block diagram showing an embodiment of the crossing trunk number counting device according to the present invention, and FIG. 1(b) shows the main signals in the crossing truck number counting device of FIG. 1(a). The timing chart shown in FIG. 2 is a block diagram showing a conventional cross track number counting device. A... Close seek or track jump command signal, B...
...Mask signal, 1... Optical disk, 3... Optical pickup, 4... Differential amplifier, 5.11... Switch, 6... Phase compensation circuit, 7... Driver, 8...
...Speed detection circuit, 9...Command speed circuit, 10...
Counter, 12... Binarization circuit, 13... Time constant circuit, 14.15... AND gate.

Claims (1)

[Claims] means for counting the number of times a track error signal indicating a positional deviation of the objective lens with respect to the track reaches the "0"level; and means for activating the counting means after a predetermined period of time has elapsed after the rise of the fine seek or track jump command signal. traversing, wherein the counter means starts counting by the starting means and switches from close seek or track jump control to tracking control when the number of tracks corresponding to the close seek or trunk jump is counted. Track number counting device.