JPH0536095A - Count circuit for disk device - Google Patents

Abstract

PURPOSE:To attain the exact count of a track detection pulse even when the moving direction of an optical head is inverted by detecting the moving direction of the head in response to a groove detection pulse and a tracking error signal corresponding to a track sum signal. CONSTITUTION:A counter circuit 59 switches UP/DOWN from a direction signal from a direction detecting circuit 58, and the DOWN count is operated in the UP count area each time a track detection pulse from a pulse correcting circuit 53 is supplied. Even when the moving direction of the optical head to a disk is inverted due to the eccentricity of the disk or the like when the head is moved at a low speed, the track detection pulse can be exactly counted by switching the UP/DOWN by the direction signal from the circuit 58.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention counts the track position of an optical disk as a laser beam irradiation position of an optical head used in an optical disk device for recording information on an optical disk or reproducing information from the optical disk. The present invention relates to a count circuit of a disk device which is a track count circuit.

[0002]

2. Description of the Related Art In an image filing system,
An optical disk device is used. In this optical disk device, data is recorded on a track or recorded data is reproduced from the track while rotating an optical disk having a large number of spiral or concentric tracks.

The original is two-dimensionally optically scanned, and the image data of the original is photoelectrically converted into electric image data, and this electric image data is optically recorded on a track of an optical disk by an optical head. To be done. This recorded data is
If necessary, it is searched by the optical head as well, and the
Played as copy or soft copy.

In an optical head installed near the lower surface of a rotating optical disc, laser light output from a semiconductor laser oscillator is focused on the optical disc by an objective lens to record data. , Or the recorded data is reproduced. The optical head is tracked, and the track of the optical disk is followed by the laser light focused by the objective lens. Focusing is performed and the laser light is focused on the track of the optical disk by the objective lens.

In such an optical disk apparatus, a counter circuit has been developed which counts the moving track position of the optical head using the track difference signal and the track sum signal and outputs the moving speed signal of the optical head with respect to the optical disk. ..

However, in such an apparatus, even if the optical head moves in the opposite direction to the optical disk due to eccentricity of the optical disk or the like while the optical head is moving at a low speed, the counter circuit causes the track to move. There is a problem in that a count error occurs because the subtraction of the number of detected pulses is added.

[0007]

Conventionally, there has been a problem that track detection pulses cannot be accurately counted when the moving direction of the optical head with respect to the disk is reversed due to eccentricity or the like.

The present invention has been made in view of the above points, and provides a counting circuit of a disk device capable of accurately counting track detection pulses even when the moving direction of the optical head with respect to the disk is reversed due to eccentricity or the like. The purpose is to

[0009]

According to the present invention, there is provided an optical head having a condensing means for condensing light on a disk having a track and a detecting means for detecting light from the disk. Moving means for moving the condensing means in a direction orthogonal to the optical axis thereof, first generating means for generating a tracking error signal for the track of the disk by the detection signal from the detecting means, and detection signal from the detecting means Thus, in the disk device having the second generation means for generating the track sum signal for the track of the disk, the first output for outputting the groove detection pulse in response to the track sum signal from the second generation means. Means for responding to the groove detection pulse from the first output means and the tracking error signal from the first generating means. Depending on the detection result of the detecting means for detecting the moving direction of the optical head, the second output means for outputting the track detecting pulse in response to the tracking error signal from the first generating means, , Counting means for adding or subtracting the number of track detection pulses from the second output means.

[0010]

According to the present invention, in the above-mentioned structure, the optical head is moved in the radial direction of the disk, and the tracking error signal obtained by detecting the light from the disk as the optical head moves. In a disk device that generates a track sum signal, a groove detection pulse is output in response to the track sum signal, and the moving direction of the optical head is detected in response to the groove detection pulse and the tracking error signal. The number of track detection pulses output by the tracking error signal is added or subtracted according to the detected moving direction of the optical head.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show a disk device. That is, a recording track (groove) is formed in a spiral shape or a concentric shape on the surface of a disk (recording medium) 1 including an optical disk, and the disk 1 is rotated by a motor 2 at a constant speed, for example. To be done. The motor 2 is controlled by a motor control circuit 18. Recording / reproduction of information on / from the disc 1 is performed by an optical head 3 provided below the disc 1.

Although the disk 1 uses a recording film for forming pits by punching holes,
A recording film using a phase change or a multilayer recording film may be used, or a magneto-optical disk or the like may be used as the disk. In the above case, the configurations of the optical head and the like are similarly changed.

An objective lens 6 is held on the optical head 3 by a wire or a leaf spring (not shown). The objective lens 6 is moved by a driving coil 5 in the focusing direction (optical axis direction of the lens) and driven. The coil 4 allows movement in the tracking direction (direction orthogonal to the optical axis of the lens).

The laser light generated by the semiconductor laser oscillator 9 driven by the laser control circuit 14 is
The disc 1 is irradiated through the collimator lens 11 a, the half prism 11 b, and the objective lens 6, and the reflected light from the disc 1 is the objective lens 6 and the half prism 1.
The light is guided to the photodetector 8 via the lens 1b, the condenser lens 10a, and the cylindrical lens 10b. The photodetector 8
Is composed of four divided photodetection cells 8a, 8b, 8c and 8d.

The output signal of the photodetector cell 8a of the photodetector 8 is supplied to one end of the adders 30a and 30c through the amplifier 12a, and the output signal of the photodetector cell 8b is supplied to the amplifier 1.
2b is supplied to one end of the adders 30b and 30d,
The output signal of the photodetection cell 8c is supplied to the other ends of the adders 30b and 30c via the amplifier 12c, and the photodetection cell 8d
Of the output signal of the adder 30a, 3a through the amplifier 12d.
It is supplied to the other end of 0d.

Here, as shown in FIG.
The head amplifier 12 is composed of a, ..., 12d,
The adder unit 30 includes the adders 30a, 30b, 30c, and 30d.
0 is configured.

Further, the photodetector cell 8a of the photodetector 8,
The output signals of 8b, 8c and 8d are respectively fed to the amplifier 12
It is supplied to the high speed adder 41 via a, 12b, 12c and 12d.

The output signal of the adder 30a is supplied to the inverting input terminal of the differential amplifier OP1 which constitutes the track error signal circuit 42, and the output signal of the adder 30b is supplied to the non-inverting input terminal of the differential amplifier OP1. Is supplied. As a result, the differential amplifier OP1 includes the adders 30a and 30b.
The track error signal (track difference signal) is supplied to the tracking control circuit 16 and the track counter circuit 35 in accordance with the difference between the two.

Further, the output signals of the adders 30a and 30b are supplied to a track sum signal circuit 43 composed of adders. As a result, the track sum signal circuit 43 outputs the track sum signal according to the sum of the adders 30a and 30b to the focusing control circuit 15 and the tracking control circuit 1.
6 and the track counter circuit 35. The track sum signal output from the track sum signal circuit 43 has a waveform that reflects the difference in the reflectance of the disk surface of the disk 1 and the diffraction when it crosses a groove (track groove).

The tracking control circuit 16 produces a track drive signal according to the track error signal supplied from the differential amplifier OP1 and the track sum signal supplied from the track sum signal circuit 43.

The track drive signal output from the tracking control circuit 16 is supplied to the drive coil 4 in the tracking direction. Further, the track error signal used in the tracking control circuit 16 is supplied to the linear motor control circuit 17.

The track counter circuit 35 is a disk on which the beam light from the objective lens 6 is irradiated according to the track error signal supplied from the differential amplifier OP1 and the track sum signal supplied from the track sum signal circuit 43. The track position on the disk 1 is counted and the relative speed between the light beam and the disk 1 is detected.
The track position counted by the track counter circuit 35 is output to the CPU 23, and the speed signal is output to the linear motor control circuit 17.

The linear motor control circuit 17 receives the track error signal from the tracking control circuit 16 and the CPU 23.
A linear motor 31 to be described later in accordance with a movement control signal from the
A voltage corresponding to the moving speed is applied to the drive coil (conductor) 13 inside.

The output signal of the adder 30c is supplied to the inverting input terminal of the differential amplifier OP2, and the output signal of the adder 30d is supplied to the non-inverting input terminal of the differential amplifier OP2. As a result, the differential amplifier OP2 supplies a signal regarding the focus point to the focusing control circuit 15 according to the difference between the adders 30c and 30d. The output signal of the focusing control circuit 15 is supplied to the focusing drive coil 5 and is controlled so that the laser beam is always in perfect focus on the disc 1.

Each photodetecting cell 8a of the photodetector 8 in the state where focusing and tracking are performed as described above ,.
The sum signal of the outputs of 8d, that is, the output signal from the high-speed adder 41 reflects the change in the reflectance from the pits (recording information) formed on the track. This signal is supplied to the signal processing circuit 19, and the recording information and address information (track number, sector number, etc.) are reproduced in this signal processing circuit 19.

The reproduction signal (reproduction information) reproduced by the signal processing circuit 19 is output to the disk control device 33 as an external device through the interface circuit 32. In addition, in the preceding stage of the laser control circuit 14, a recording signal generation circuit 3 as a modulation circuit for modulating the recording signal.
4 are provided.

Further, the disk drive has a focusing control circuit 15, a tracking control circuit 16,
A D / A converter 22 used for exchanging information between the linear motor control circuit 17 and the CPU 23 is provided.

Further, the tracking control circuit 16 is
The objective lens 6 is moved in accordance with the track jump signal supplied from the CPU 23 via the D / A converter 22, and the beam light is moved by one track.

The above laser control circuit 14, focusing control circuit 15, tracking control circuit 16, linear motor control circuit 17, motor control circuit 18, signal processing circuit 1
9, recording signal creation circuit 34, track counter circuit 35
Etc. are controlled by the CPU 23 via the bus line 20.
A predetermined operation is performed by the program stored in.

The track counter circuit 35, as shown in FIG. 3, has an AGC (auto gain control).
Circuit 51, track detection pulse signal extraction circuit 52, pulse correction circuit 53, frequency-speed conversion circuit 54, track error waveform shaping circuit 55, track sum waveform shaping circuit 5
6, a groove detection pulse circuit 57, a direction detection circuit 58, and a counter circuit 59.

The AGC circuit 51 uses the track error signal supplied from the track error signal circuit 42 and the track sum signal from the track sum signal circuit 43 to form pits and irregularities formed on the track from the track error signal. It outputs a track detection signal from which a noise signal caused by dust, dirt, scratches, etc. is removed.

That is, in the track error signal, as shown in FIG.
As shown in (b) of FIG. 4 (see (a) of FIG. 4)
The noise signals ND1 and ND2 generated by the pits, unevenness, dust, dirt, scratches, etc. formed on the above are superimposed. The noise signal ND1 is a signal having a low reflectance or unevenness, and the noise signal ND2 is a signal having a high reflectance.

Further, the track sum signal includes (c) of FIG.
As shown in, the noise signals ND′1 and ND′2 are superimposed in synchronization with the noise signals ND1 and ND2.

As a result, the AGC circuit 51 amplifies an amplifier (not shown) that amplifies the track error signal supplied from the track error signal circuit 42 according to the signal level of the track sum signal from the track sum signal circuit 43. By controlling the rate (gain), a track detection signal from which a noise signal has been removed is output as shown in FIG. As a result, the positive and negative peak values corresponding to each track are corrected to a substantially constant value and output. AGC circuit 51
The track detection signal from is output to the track detection pulse signal extraction circuit 52 and the track error waveform shaping circuit 55.

The track detection pulse signal extraction circuit 52
In the state where the moving speed of the optical head 3 is slow, the track detection signal from the AGC circuit 51 becomes NG in (a) of FIG. 6 due to a part where the groove (track groove) on the disk 1 is interrupted or a dust. As shown in the figure, this is a circuit in which one pulse is surely generated for one groove when the level becomes zero. As shown in FIG.
1, 82 and a flip-flop circuit (FF circuit) 83.

The comparator 81 binarizes the track detection signal from the AGC circuit 51 by comparing it with a constant value V1 between the zero level and the positive peak value, and FIG.
The signal as shown in (b) is output. The comparator 82 binarizes the track detection signal from the AGC circuit 51 by comparing the track detection signal with a constant value V1 between the zero level and the negative peak value.
It outputs the signal as shown in.

The FF circuit 83 is a circuit that maintains the set state until the output of the comparator 81 becomes low level once the output of the comparator 81 becomes high level once. This allows
As shown in FIG. 6 (a), the FF circuit 83 operates even if the track detection signal becomes zero level.
As shown in (d) of (1), one pulse is surely emitted to one groove. The output of the FF circuit 83, that is, the output of the track detection pulse signal extraction circuit 52 is output to the pulse correction circuit 53 as a track detection pulse.

The pulse correction circuit 53 is used in the optical head 3
In the state where the moving speed is high, the spot of the laser beam from the optical head 3 enters the part where the groove (track groove) on the disk 1 is interrupted, and the track detection pulse from the track detection pulse signal extraction circuit 52 is detected. As shown in FIG. 8 (a), when the pulse disappears, one pulse is surely generated for one groove. As shown in FIG. 7, the AND circuit 91, It is composed of counter circuits 92 and 94, a latch circuit 93, a clock circuit 95, and an OR circuit 98.

The counter circuit 92 counts the number of clocks from the previous track detection pulse by starting counting the clocks from the clock circuit 95 at the fall of the previous track detection pulse. The count value is output to the latch circuit 93. The latch circuit 93 latches the number of clocks counted by the counter circuit 92 at the rising edge of the track detection pulse as the track detection pulse interval T1. At the falling edge of the track detection pulse, the content of this latch becomes a complement of "1". It is converted and output to the counter circuit 94.

The counter circuit 94 starts counting the clocks from the clock circuit 95 when the latch contents are loaded from the latch circuit 93, and the latch circuit 9 starts counting by this counting.
The time T2 (T2 <T which is shorter than the track detection pulse interval T1 of the previous pulse according to the content of the latch supplied from 3).
The mask signal of 1) (see (b) of FIG. 8) is applied to the AND circuit 9
1 to the track detection pulse interval T1 of the previous pulse
Time T3 (T1 <T3 <2
The correction pulse (see (c) of FIG. 8) is output to the OR circuit 98 when the next track detection pulse does not rise even after T1).

Since the correction pulse from the counter circuit 94 is output to its own load terminal,
Further, even when the pulse does not come, the correction pulse is added at every track detection pulse interval T1 before being ablated from the correction pulse (see (c) of FIG. 8).

The AND circuit 91 is a counter circuit 94.
Track detection pulse interval T1 by the mask signal from
The pulse (noise) within the shorter time T2 is removed, and the track detection pulse from the AND circuit 91 is output to the counter circuits 92, 94, the latch circuit 93, and the OR circuit 98.

As shown in (d) of FIG. 8, the OR circuit 98 counts the logical sum signal of the track detection pulse from the AND circuit 91 and the correction pulse from the counter circuit 94 as a corrected track detection pulse and count circuit 59. Is output to. The latch contents of the latch circuit 93 are as follows.
It is output to the frequency-speed conversion circuit 54.

In such a configuration, the counter circuit 9
In 2, the number of clocks from the clock circuit 95 between the previous track detection pulse is counted and the latch circuit 93 latches and latches this count value at the timing of the track detection pulse. , ”Is output.

When the counter circuit 94 correctly outputs the track detection pulse, the output of the latch circuit 93 is loaded at the timing of the track detection pulse, and the clock from the clock circuit 95 is counted from the loaded value to a constant value. As shown in (b) of FIG. 8, a time T2 corresponding to the track detection pulse interval T1 immediately before the previous pulse.
A signal for masking the track detection pulse for (T2 <T1) is output to the AND circuit 91.

In addition, a time T3 (T1 <T1) that is sufficiently longer than the track detection pulse interval T1 and shorter than twice from the previous pulse.
When the next pulse is not waited for T3 <2T1), the correction pulse is output, and the OR circuit 98 takes the logical sum of this correction pulse and the track detection pulse. Further, even when the pulse does not come, the correction pulse is added at every track detection pulse interval T1 before being ablated from the correction pulse (see (c) of FIG. 8).

The frequency-speed conversion circuit 54 divides the frequency detected from the latch contents supplied from the latch circuit 93 by the time (1 / T) to obtain the relative speed between the optical head 3 and the disk 1. The speed signal is converted and is output to the linear motor control circuit 17.

The track error waveform shaping circuit 55 is
A portion where the track detection signal from the AGC circuit 51 has become zero level due to a portion where the groove (track groove) on the disk 1 is interrupted or a portion such as dust, as shown by NG ′ in FIG. 9 is removed.
As shown in FIG. 3, it is composed of half-wave rectification circuits 101 and 102, an upper end detection circuit 103, a lower end detection circuit 104, and an addition circuit 105. The half-wave rectifier circuit 101 is a circuit that outputs a signal only on the plus side of the track detection signal (see FIG. 10B) supplied from the AGC circuit 51 as shown in FIG. The half-wave rectifier circuit 102 is A
This circuit outputs a signal only on the minus side of the track detection signal (see (d) of FIG. 10) supplied from the GC circuit 51 as shown in (a) of FIG.

The upper end detection circuit 103 is a half-wave rectification circuit 101.
The signal which detected the upper end of the half-wave rectification from (Fig. 10 (c)
Output). The lower end detection circuit 104 outputs a signal obtained by detecting the lower end of the half-wave rectification from the half-wave rectification circuit 102 (see (e) in FIG. 10). The adder circuit 105 adds the upper end detection signal from the upper end detection circuit 103 and the lower end detection signal from the lower end detection circuit 104, and the addition result is a track detection signal from which noise is removed (see (f) in FIG. 10). ) Is output.

According to such a configuration, the half-wave rectifier circuit 1
01 outputs a signal only on the plus side of the track detection signal, and an upper end detection circuit 103 outputs a signal whose upper end is detected. Further, the half-wave rectification circuit 102 outputs a signal only on the minus side of the track detection signal, and the lower-end detection circuit 104 outputs a signal whose lower end is detected.
Then, the adder circuit 105 outputs a sum signal of the upper end detection signal and the lower end detection signal. As a result, it is possible to remove a portion where the track detection signal has become zero level without causing diffraction due to a broken portion of the groove or dust. The track detection signal shaped by the track error waveform shaping circuit 5 is output to the direction detection circuit 58.

The track sum waveform shaping circuit 56 is a circuit which is composed of an upper end detection circuit and shapes the track sum signal from the track sum signal circuit 43. The shaped track sum signal is output to the groove detection pulse circuit 57. To be done.
For example, a track sum signal as shown in FIG. 12B is output by removing noise from the track sum signal as shown in FIG. 12A. As a result, the influence of the pits, the unevenness, the broken portion NS, etc. formed on the track included in the track sum signal is reduced.

The groove detection pulse circuit 57 outputs a groove detection pulse as a pulse corresponding to a groove by the track sum signal supplied from the track sum waveform shaping circuit 56. As shown in FIG. Detection circuit 111,
It is composed of a comparison circuit 112. The lower-end detection circuit 111 performs lower-end detection of the track sum signal supplied from the track-sum waveform shaping circuit 56 at a low frequency. In contrast to the track-sum signal shown in FIG. 12B, FIG. The bottom detection signal shown in is output. Comparison circuit 112
Compares the track sum signal supplied from the track sum waveform shaping circuit 56 with the lower end detection signal from the lower end detection circuit 111, and crosses the lower end of the track sum signal, that is, the groove as shown in FIG. It outputs a groove detection pulse as a timing signal.

That is, the lower end detection circuit 111 performs the lower end detection of the track sum signal from the track sum waveform shaping circuit 56 at a low frequency and outputs the lower end detection signal as shown in FIG. Then, this lower end detection signal is compared with the track sum signal from the track sum waveform shaping circuit 56, and the lower end of the track sum signal, that is, a groove detection pulse as a timing signal across the groove as shown in FIG. Is output. The groove detection pulse from the comparison circuit 112 of the groove detection pulse circuit 57 is output to the direction detection circuit 58.

The direction detecting circuit 58, when it is judged that the moving speed is slow by the speed signal from the frequency-speed converting circuit 54, the track detecting signal from the track error waveform shaping circuit 55 and the groove detecting pulse circuit 57. It is to detect whether the inclination of the track detection signal when crossing the groove is positive or negative by using the groove detection pulse from No. 3, and to determine the moving direction of the laser light by the optical head 3, as shown in FIG. Differentiating circuit 121, comparing circuit 122, latch circuit 12
3, a speed comparison circuit 124, an AND circuit 125, and an exclusive OR circuit (XOR circuit) 126.

The differentiating circuit 121 differentiates the track detection signal from the track error waveform shaping circuit 55 as shown in FIG. 14A, and the differential signal as shown in FIG. Output to. Comparison circuit 122
Compares the differential signal from the differentiating circuit 121 at zero level, and outputs an output signal as the comparison result as shown in FIG. 14C to the latch circuit 123.

The speed comparison circuit 124 compares whether or not the absolute value of the speed signal from the frequency-speed conversion circuit 54 is faster than a predetermined moving speed (above a certain value), and when it is faster than the predetermined moving speed. Closes the gate of the AND circuit 125, masks the groove detection pulse from the groove detection pulse circuit 57, opens the gate of the AND circuit 125 when it is slower than a predetermined moving speed, and detects the groove from the groove detection pulse circuit 57. The pulse is output to the latch circuit 123.

When the groove detection pulse is supplied from the groove detection pulse circuit 57 as shown in FIG. 14D via the AND circuit 125, the latch circuit 123 is as shown in FIG. 14C. When the output signal from the comparison circuit 122 changes, the direction signal is switched and output to the XOR circuit 126 as shown in (e) of FIG.

The XOR circuit 126 outputs the exclusive OR of the direction signal from the latch circuit 123 and the access direction signal from the CPU 23 to the counter circuit 59 as a direction signal. The access direction signal from the CPU 23 is a signal for switching the output to the high level when the access direction of the optical head 3 is from the inner circumference to the outer circumference or from the outer circumference to the inner circumference.

The counter circuit 59 switches up / down according to the direction signal from the direction detection circuit 58, and in this switched state, every time the track detection pulse from the pulse correction circuit 53 is supplied, up-counting or down-counting is performed. It is done.

As a result, the count value of the counter circuit 59 can be obtained even if the optical head 3 moves in the opposite direction due to the eccentricity of the disk 1 while the optical head 3 is moving at a low speed. , Direction detection circuit 5
By switching up / down by the direction signal from 8, the track detection pulse can be accurately counted.

As described above, the moving direction of the optical head with respect to the disc is opposite due to the eccentricity or the like even on the irregularities of the disc or the pit portions having different reflectances, dust, scratches, broken grooves, and the like. Can accurately count track detection pulses.

[0062]

As described above in detail, according to the present invention,
It is possible to provide a counting circuit of a disk device capable of accurately counting track detection pulses even if the optical head moves in the opposite direction to the disk due to eccentricity or the like.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of a disk device according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a photodetector, a head amplifier unit, and an addition unit in FIG.

3 is a block diagram showing a circuit configuration of a track counter circuit of FIG.

FIG. 4 is a diagram for explaining waveforms of the AGC circuit of FIG.

5 is a diagram showing a circuit configuration of a track detection pulse signal extraction circuit of FIG.

FIG. 6 is a diagram for explaining a waveform of the track detection pulse signal extraction circuit of FIG.

7 is a diagram showing a circuit configuration of a pulse correction circuit of FIG.

FIG. 8 is a diagram for explaining the waveform of the pulse correction circuit in FIG.

9 is a block diagram showing a circuit configuration of the track error waveform shaping circuit of FIG.

10 is a diagram for explaining the waveform of the track error waveform shaping circuit of FIG.

11 is a block diagram showing a circuit configuration of the groove detection pulse circuit of FIG.

FIG. 12 is a diagram for explaining waveforms of the track sum waveform shaping circuit and the groove detection pulse circuit of FIG. 1.

13 is a diagram showing a circuit configuration of the direction detection circuit of FIG.

14 is a diagram for explaining the waveform of the direction detection circuit of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Disk (recording medium), 3 ... Optical head, 6 ... Objective lens, 8 ... Photodetector, 12 ... Head amplifier part, 17 ...
Linear motor control circuit, 19 ... Signal processing circuit, 23 ... C
PU, 30 ... Addition unit, 31 ... Linear motor, 35 ... Track counter circuit, 41 ... High-speed adder, 42 ... Track error signal circuit, OP1, OP2 ... Differential amplifier, 43 ...
Track sum signal circuit, 51 ... AGC circuit, 52 ... Track detection pulse signal extraction circuit, 53 ... Pulse correction circuit, 5
4 ... Frequency-speed conversion circuit, 55 ... Track error waveform shaping circuit, 56 ... Track sum waveform shaping circuit, 57 ... Groove detection pulse circuit, 58 ... Direction detection circuit, 59 ... Counter circuit.

Claims (1)

Claim: What is claimed is: 1. An optical head having a condensing means for condensing light on a disk having a track, and a detecting means for detecting light from the disk, and a collection of the optical head. A moving means for moving the optical means in a direction orthogonal to its optical axis, and a detection signal from the detecting means for generating a tracking error signal for the track of the disc.
And a second generation means for generating a track sum signal for the track of the disk by the detection signal from the detection means, the track sum signal from the second generation means being pls respond,
First output means for outputting a groove detection pulse, and movement of the optical head by the moving means in response to the groove detection pulse from the first output means and the tracking error signal from the first generating means. Detection means for detecting the direction; second output means for outputting a track detection pulse in response to the tracking error signal from the first generation means; and the second output means for detecting the detection result of the detection means. A counting circuit for adding or subtracting the number of track detection pulses from the output means of the above, and a counting circuit of the disk device.