JPH08147716A - Track retrieving device for disk device - Google Patents

Abstract

PURPOSE: To make a track counting to be continued by an interpolated clock signal even through a binary signal (a signal obtained by binarizing a track deviation signal) normally outputted from an RF amplifier is interrupted at the time an optical pickup crosses over a boundary. CONSTITUTION: The optical pickup 2 performs the track retrieving of a disk 1 in which different areas known as an PIT region and a GRV region are provided with a track counting system. At this time, when the area of the starting point of the optical pickup 2 differs from the region of a target track, at the time the pickup 2 crosses over the boundary between both regions, the interpolated clock signal (the binary signal) having a frequency corresponding to the moving speed of the optical pickup 2 is generated in an interpolated signal generating circuit 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc device such as a mini disc device which has a rewritable area (RW area) and a read-only area (ROM area) provided on the same recording medium. The present invention relates to a track search device of a disk device for searching.

[0002]

2. Description of the Related Art Conventionally, like a magneto-optical disk device, a rotating disk-shaped disk is irradiated with a light beam emitted from a light source such as a semiconductor laser, which is converged and applied to the disk. There are devices that reproduce recorded signals.

The above disk has a track pitch of 1.
Minute tracks of 6 μm are provided concentrically or spirally. The signal recorded on the disc is reproduced by receiving the reflected light from the disc by the photodetector while applying the tracking servo so that the light beam is always located on the track. Then, the track shift signal required for tracking servo is also detected by the reflected light input to the photodetector. That is, the tracking servo is performed by feeding back the track deviation signal to the tracking actuator that moves the light beam irradiated on the disk in the radial direction of the disk.

Further, among the many tracks provided on the disk as described above, a track search is performed to move the light beam to a target track. Track search is performed by turning off the tracking servo and moving the actuator in the radial direction. As one of the typical methods of track search, there is a track counting method in which a light beam reaches a target track by counting binarized track deviation signals, as described below.

A track deviation signal when a light beam crosses a track is detected by a track deviation detecting means for detecting a positional deviation between the light beam and the track, and this output signal is generally a threshold as shown in FIG. It becomes a sinusoidal signal that oscillates around the level. This sinusoidal signal is binarized by the binarizing means to be a binarized signal (pulse signal) as shown in FIG.

Then, by counting the number of the binarized signals, the number of tracks where the light beam crosses the tracks is calculated. The light beam moves to the target track so that this track number matches a predetermined track number. When the track search is completed in this way, the above-mentioned tracking servo is activated again.

By the way, as an example of a disc having two areas, that is, an RW (recordable) area and a ROM (reproduction-only) area, on the same disk, there is a mini disk which is a recordable and reproducible recording medium. There are three types of mini discs, a read-only disc, a recording / playback disc, and a hybrid disc, and the maximum capacity of the disc is 140 megabytes.

The read-only disc, like the compact disc, is composed of only the PIT area. The recording / reproducing disc has two types of regions on the same disc, such as a PIT (ROM) region at the innermost circumference and an entire RW region. The hybrid disc is a disc in which the RW area and the ROM area are divided at arbitrary positions. The recordable area of the latter two discs is GR
It is called a V region, and a meandering groove is engraved, and an information signal is written in this groove.

An apparatus for recording or reproducing the above-mentioned mini disk is performed by an optical pickup 2 as shown in FIG. In this optical pickup 2, the laser light emitted from a semiconductor laser (not shown) is used as the objective lens 21.
The light is converged on the disk 1 by the beam splitter 22, the reflected light is deflected by the beam splitter 22, further divided into two by the deflecting beam splitter 24, and taken into the two light receiving elements 25 and 26.

In the PIT area of the disc 1, FIG.
As shown in FIG. 1A, PITs 51 ... Are formed on the signal surface. When the PIT 51 ... Is irradiated with laser light, the amount of return light is reduced as shown in (c) of the figure, whereas when the laser light is irradiated to a portion other than the PIT 51 ..., it is shown in (b) of the same figure. As you can see, there is more light returned. At this time, the outputs of the light receiving elements 25 and 26 are 0 when there is much returning light and 1 when there is little returning light, as shown in FIG. Then, these outputs are added by an error amplifier 31 for a read-only mini disk provided outside the optical pickup 2, so that "0" and "1" as shown in FIG.
An RF signal corresponding to is obtained.

On the other hand, in the GRV area of the disk 1, as shown in FIG. 13 (a), a magneto-optical film 52 having a magnetism is formed in a groove in a certain direction according to a digital signal. . When the magneto-optical film 52 is irradiated with laser light, the laser light is affected by the direction (magnetic field) of the magnetic signal and its polarization direction is slightly changed, as shown in (b) and (c) of FIG. It is twisted, reflected, and taken into the light receiving elements 25 and 26 through the polarization beam splitter 24. Then, as shown in FIG. 14, the outputs of the respective light receiving elements 25 and 26 increase or decrease depending on the direction of the polarization plane, and have different values. Therefore, the light receiving element 2
The difference (RF signal) between the signals received at 5.26 is calculated by the error amplifier 32 provided outside the optical pickup 2, so that "0" and "1" corresponding to the magnetic poles of the magneto-optical film 52 are obtained.
Is read.

In the PIT area of the recording / reproducing disc, only the information about the disc is written and the amount of information is small. Therefore, the read information is usually stored in the memory of the mini disk device. Therefore, there is almost no track search between the PIT area and the GRV area. Even if there is, the PIT area independently exists at the innermost circumference as a lead-in area for storing information on the disc, and therefore, when accessing, the optical pickup must be moved to the innermost circumference. In other words, since only part of the PIT area data is not accessed,
Mechanical control is possible.

[0013]

However, for a hybrid disc, the information in the PIT area is as large as several megabytes to hundreds of tens of megabytes and is variable, so it is difficult to store all of it in the memory. Further, according to the standard, it is assumed that the ratio of the reflectances of the PIT region and the GRV region is 4: 1, so that the track shift signal is interrupted when the region irradiated with the light beam changes. Therefore, under the current circumstances, it is necessary to switch the laser power between the PIT region and the GRV region. Furthermore, since the disc rotation control method is different in both areas (PIT area: control using the read signal (EFM signal),
GRV area: control using a groove signal (wobbling)), and this switching is also necessary.

Although the above hybrid disc has not been used for audio, it is expected to be sufficiently utilized as a data MD which is an external storage device of a computer. Therefore, in order to meet such a situation, it is necessary to realize a smooth track search between the PIT area and the GRV area.

A method disclosed in Japanese Unexamined Patent Publication No. 5-159318 is a method for smoothly performing track search for a partial ROM disk having a read-only area and a recording / playback area like the hybrid disk. There is. In this technique, the tracking offset and the tracking gain of each area are measured in advance and the adjustment values are stored in a storage device to smoothly switch the areas. According to this, it is possible to improve the accuracy of tracking control and, in turn, improve the accuracy of track search. However, this technique is not intended for the track search between the regions having different reflectances as described above, and cannot essentially solve the above problems.

The present invention has been made in view of the above circumstances, and detects the boundary between the PIT area and the GRV area during the track search, so that an internal track shift signal can be obtained instead of the interrupted track deviation signal. An object of the present invention is to provide a track search device capable of shortening the track search time by accurately counting the number of tracks by generating an insertion pulse and switching modes during this period.

[0017]

In order to solve the above-mentioned problems, the track search device according to claim 1 of the present invention is
Converging means for converging and irradiating a light beam onto a disk having a recordable area where information can be recorded by the magneto-optical effect and a read-only area where information is recorded with or without pits
Moving means for moving the converging means so that the converging point of the light beam converged by the converging means crosses the track on the disc; level detecting means for detecting the level of the reflected light reflected by the light beam on the disc; Polarization detection means for detecting the polarization of the reflected light of the beam reflected on the disk, track deviation detection means for detecting the positional deviation between the converging means and the track, and the output signal from the track deviation detection means are binarized. Binarizing means, counting means for counting the number of tracks crossed by the converging means by the number of pulses of the binarized signal by the binarizing means, and the converging means based on the number of tracks counted by the counting means. A moving control means for detecting the moving position of the moving means and controlling the moving means so as to send the converging means to the target track at an optimum speed according to the position. Click the search is started from one area of the recordable area or reproduction-only area of the disc,
When the target track to be searched is present in the other area of the disc, the level change of the reflected light by the level detecting means is detected or the polarized light is detected while the converging means is moving by the moving means. When the polarization of the reflected light is detected by the detecting means, a pseudo signal generating means for artificially generating the binarized signal instead of the binarizing means is provided.

According to a second aspect of the present invention, there is provided a track search device according to the first aspect, wherein the movement control means sets the first movement destination of the convergence means. According to the position of the target track, the track is changed to a track near the target track, and the moving means is controlled so as to move the converging means toward the target track.

In order to solve the above-mentioned problems, a track search device according to a third aspect of the present invention is the track search device according to the first aspect, in which characteristic measuring means for measuring a speed characteristic of the moving means, Speed detecting means for detecting the moving speed of the moving means, storage means for storing the speed characteristic measured by the characteristic measuring means, and speed detecting means for detecting the frequency of the binary signal output from the pseudo signal generating means. And a frequency correction means for correcting the moving speed detected by the above-mentioned method based on the speed characteristic of the moving means stored in the storage means.

According to a fourth aspect of the present invention, in order to solve the above-mentioned problems, the target track of the converging means is present after the pseudo signal generating means starts generating a binarized signal. When the operation mode of the disk device is switched in accordance with the recordable area or the reproduction-only area, the stop means for stopping the generation of the binarized signal from the pseudo signal generating means is provided.

[0021]

In the truck search device according to the first aspect,
When the track is searched, the moving means moves the converging means on the track. If the target track is in a different area from the disk area at the track search start point and the converging means crosses the boundary of the areas and the reflectances of both areas are different, the level detection means changes the level of the reflected light. If it is detected and the reflectances of both areas are equal,
The polarization of the reflected light is detected by the polarization detecting means.

Upon detection of these, the pseudo signal generating means outputs a pulse, whereby the counting means counts the number of tracks crossed by the converging means, and various modes are switched during this period. Therefore, even if the converging means crosses the boundary and enters a different area during the track search, the track count can be continued by the pseudo-generated binarized signal even if the binarized signal is interrupted. As a result, the movement control means moves the converging means based on the number of tracks.

As described above, in the track search device according to the first aspect, even when the target track is located in a different region when searching for a desired track, the boundary is detected and the binarized signal is simulated. By generating and counting the tracks, it is possible to shorten the time for track search without requiring time for regenerating the track deviation signal (binarization signal) that is interrupted when the boundary is crossed, by mode switching. it can.

In the track search device according to the second aspect, for example, when the target track of the converging means is near the boundary, the movement control means changes the first destination to a position farther from the target track and converges. The means moves from here towards the target track. This can prevent the converging means from accidentally moving into the same area without crossing the boundary. Further, it is possible to prevent the converging means from reaching the target track while the converging means outputs the binarized signal signal which is artificially generated by the pseudo signal generating means.

In the track search device according to the third aspect, when the characteristic of the moving means is measured by the characteristic measuring means in advance, the characteristic is stored in the storage means. On the other hand, in the actual track search, the moving speed of the moving means is detected by the speed detecting means. Then, the frequency correction means corrects the frequency of the binarized signal generated from the pseudo signal generation means based on the speed characteristic of the moving speed stored in the storage means according to the detected moving speed.

Thus, the frequency of the binarized signal output from the pseudo signal generating means can be quickly set according to the actual moving speed of the converging means. Further, the difference from the track shift frequency is reduced, and the accuracy of track counting can be improved.

In the track search device according to the fourth aspect, when the switching of the operation mode according to the area to which the converging means is moved is completed after the generation of the binarized signal by the pseudo signal generating means is started. Then, the pseudo signal generating means 2
The generation of the digitized signal stops. In this state, since the binarized signal can be output by the binarizing means, the binarized signal is continuously counted. As a result, after the converging means reaches the target track, it is possible to smoothly shift to disk control suitable for the area, and it is possible to shorten the time for track search.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS. In the present embodiment, as an example of application to a track search device, a data mini disk device (hereinafter referred to as "data MD device") will be taken as an example and described.

As shown in FIG. 1, the data MD device described above has an optical pickup 2, an RF (Radio Frequency) amplifier 3, a signal processing circuit 4, a buffer memory 5, and a host interface 6 for recording and reproducing the disc 1. , System controller 7, servo circuit 8, drive circuit 9, feed motor 10, spindle motor 11, head drive circuit 12, magnetic head 13, interpolation signal generation circuit 14,
A level detection circuit 15 and a polarization detection circuit 16 are provided.

The disc 1 is, for example, as shown in FIG. 2, the PIT regions 1a, GR from the inner peripheral side toward the outer peripheral side.
Different regions are alternately provided in the order of V region 1b, PIT region 1a, and GRV region 1b. In addition, as for the disc used in this embodiment, if different areas are provided alternately, PIT-GRV-PIT and GRV-PI.
A configuration such as T-GRV-PIT may be used.

As shown in FIG. 9, the optical pickup 2 as the converging means includes a semiconductor laser (not shown), an objective lens 21, a beam splitter 22, a spot lens 23, a deflecting beam splitter 24 and light receiving elements 25 and 26 as the converging means. have. As described above, the optical pickup 2 determines the amount of return light when the PIT area 1a of the disc 1 is irradiated with the laser light.
It is designed to be taken out as the output of 6. Further, the optical pickup 2 extracts the direction of the plane of polarization of the reflected light when the magneto-optical film in the GRV area 1b of the disc 1 is irradiated with the laser light as the magnitude of the output of the light receiving elements 25 and 26.

The RF amplifier 3 is an error amplifier 3 shown in FIG.
1 and 32, and based on the output signals of the light receiving elements 25 and 26 described above, the PIT region 1
While generating the RF signal representing the recording information of a, the error amplifier 32 is used to generate the RF signal representing the recording information of the GRV area 1b. Also, RF amplifier 3
Generates a servo signal such as a tracking error signal and a focus error signal from the signal from the optical pickup 2. Further, the RF amplifier 3 is adapted to generate a track shift signal based on the signal from the optical pickup 2, binarize the track shift signal, and output it as a binarized signal (see FIG. 10). It has a function as a track deviation detecting means and a binarizing means.

The signal processing circuit 4 uses the RF amplifier 3 during reproduction.
The signal amplified in (1) is subjected to processing such as demodulation and error correction, and the processed signal is transferred to the host interface 6. Further, the signal processing circuit 4 is adapted to add an error correction code, modulate, etc. to the data transferred from the host interface 6 and output it to the head drive circuit 12 during recording. Furthermore, the signal processing circuit 4
Divides the clock of the frequency (33MHz, 20MHz, etc.) output from an external crystal oscillator (not shown),
Further, each processing as described above is performed with reference to a plurality of clocks generated by waveform shaping.

The buffer memory 5 is a working RAM (Random Access Memory) of the host interface 6. Further, the buffer memory 5 stores the speed characteristic of the feed motor 10 measured by the system controller 7 in advance, as will be described later, and has a function as a storage means.

At the time of reproduction, the host interface 6 uses the buffer memory 5 to transmit the signal sent from the signal processing circuit 4 to an IDE (Integrated Device Electronni
While the data is transferred to the host computer after being converted into a format such as cs), the data sent from the host computer at the time of recording is transferred to the signal processing circuit 4 after being subjected to the reverse processing at the time of reproduction. The host interface 6 is communicatively connected to the system controller 7, and the transfer is controlled by the system controller 7.

The system controller 7 includes a servo circuit 8
It is a microcomputer that controls the operation of the entire system such as. In particular, the system controller 7 outputs to the servo circuit 8 an ON / OFF signal for turning on the servo loop when the track search is completed, while turning off the servo loop when the track search is required. Has become. In addition, the system controller 7
Has the following functions for track search.

(1) Function as a track count (counting means) for counting the binarized signal from the RF amplifier 3 (2) Function for controlling the movement of the optical pickup 2 by the track counting method (movement control means) (3 ) Function of switching to the interpolating clock mode by the boundary detection signal detected by the level detecting circuit 15 and the polarization detecting circuit 16 (4) Canceling the interpolating clock mode at the end of the mode switching and inserting the signal into the interpolating signal generating circuit 14. Function of stopping the output of the inserted clock signal (stopping means) (5) Function of measuring the characteristics of the optical pickup 2 (characteristic measuring means) (6) Function of detecting the moving speed of the optical pickup 2 (speed detecting means) (7) ) Function to correct pulse frequency in interpolation clock mode (frequency correction means) At the time of a rack jump, when the optical pickup 2 passes the boundary between both areas, the track shift signal is not output (or is not output at the correct frequency), so that the interpolation signal generation circuit 14 replaces the track count signal. Is a mode for generating an interpolated clock signal.

The servo circuit 8 is a circuit for performing servo control of the feed motor 10 and the spindle motor 11 based on the servo signal generated by the RF amplifier 3, and its operation is controlled by the system controller 7. There is.

The drive circuit 9 is a circuit for driving the feed motor 10 and the spindle motor 11 under the control of the servo circuit 8. Further, the drive circuit 9 turns ON / O the servo loop based on the ON / OFF signal from the system controller 7 input via the servo circuit 8.
It is supposed to FF.

The head drive circuit 12 is a circuit for driving the magnetic head 13 based on the modulation signal from the signal processing circuit 4.

As shown in FIG. 3, the interpolation signal generating circuit 14 includes a serial / parallel converter 41 and a decoding circuit 4.
2. The register / timing generation circuit 43 and the counter 44. The interpolation signal generation circuit 14 is
As described below, a binarized signal is artificially generated in place of the RF amplifier 3 and has a function as a pseudo signal generating means.

In this interpolating signal generating circuit 14, when the system shifts to the interpolating clock mode, the system controller 7
The serial frequency select signal output from the parallel frequency converter is converted by the serial / parallel converter 41 into a parallel signal at the timing of the MHz order clock used in the signal processing circuit 4, and the parallel signal is decoded by the decoding circuit 42. Decoding of the signal is performed. Then, the register / timing generation circuit 43 outputs the initial value based on the output of the decoding circuit 42 by the clock. Further, the register / timing generation circuit 43 also outputs a load signal to be given to the counter 44.

Then, the optimum initial value set by the register / timing generation circuit 43 is read into the counter 44 by the load signal. When an appropriate clock is taken out of the clocks output by the signal processing circuit 4 and given to the counter 44, the clock is counted by the counter 44. After that, when the count value reaches a certain value, the output of the counter 44 is inverted (1 or 0) to output the interpolated clock signal.

Level detection circuit 1 as level detection means
Reference numeral 5 is a circuit for detecting a difference in level of the output signals of the light receiving elements 25 and 26 between the reflected light from the PIT area 1a and the reflected light from the GRV area 1b. The laser power during reproduction of the optical pickup 2 is the PIT area 1a and the GRV area 1b.
If the reflectances of and are different, it is the opposite of this reflectance ratio,
It will be about 1: 4. As described above, when the reflectances of the regions are different from each other, when reaching the boundary between the PIT region 1a and the GRV region 1b, the level of the signal received by the light receiving elements 25 and 26 changes from the PIT region 1a to the GRV region 1b. Of the GRV region 1b is reduced to 1/4 times when moving
When moving to the T region 1a, it rises four times. When the level detection circuit 15 detects this change, it outputs a switching request signal (boundary detection signal) for switching to the interpolation clock mode to the system controller 7.

Polarization detection circuit 16 as polarization detection means
Is a circuit for detecting that the polarized light is received from the output signals of the light receiving elements 25 and 26. As described above (see FIGS. 12 and 14), the signals of the reproduction system differ between the PIT area 1a and the GRV area 1b, depending on whether the signals received by the light receiving elements 25 and 26 are the sum or the difference. PIT area 1a to G
When moving to the RV region 1b, the signals received by the two light receiving elements 25 and 26 are the same in the PIT region 1a, but when they pass through the boundary and enter the GRV region 1b, the signals received in the groove portion are different. . That is, the polarization detection circuit 16 compares the two signals from the light receiving elements 25 and 26, detects the polarization when a difference appears and outputs the switching request signal, and also when the difference between the two signals disappears. A switching request signal is output.

When reproducing information from the disk 1 in the data MD device having the above-described structure, first, the spindle motor 11 driven by the drive circuit 9 is driven.
Thus, the disk 1 is rotationally driven. Next, the feed motor 10 driven by the drive circuit 9 feeds the optical pickup 2 in the radial direction of the disc 1, and the optical pickup 2 reads the information recorded on the disc 1.

The signal read by the optical pickup 2 is converted into an RF signal by the RF amplifier 3 and amplified, and sent to the signal processing circuit 4. Further, the RF amplifier 3 generates servo control signals such as a focus error signal and a tracking error signal from the signal read by the optical pickup 2. These servo control signals are output to the servo circuit 8 and the system controller 7.

Then, the servo circuit 8 controls the drive circuit 9 so as to apply focus, tracking and servo of the spindle motor 11 based on the servo control signal and the command signal from the system controller 7. Further, the drive circuit 9 drives the optical pickup 2, the feed motor 10 and the spindle motor 11 based on the control signal from the servo circuit 8.

On the other hand, when recording information on the disc 1, the signal input from the host computer is sent to the signal processing circuit 4 after the host interface 6 decodes a predetermined format. In the signal processing circuit 4,
Modulation and error correction are performed while using the buffer memory 5 as a working memory. Further, the head drive circuit 12 is driven by the signal processing circuit 4, and the magnetic head 13 is driven.
Thus, a magnetic field is applied to the disc 1 and the optical pickup 2 irradiates the disc 1 with laser light. As a result, the magnetization direction of the magneto-optical film is rewritten, and a signal is recorded on the disc 1.

Next, a track search when the optical pickup 2 is moved to a track in a region having a different state at the time of reproduction and recording in this data MD device will be described below.

First, based on the signal output from the system controller 7, the drive circuit 9 turns off the tracking servo and sends a jump signal to the feed motor 10. As a result, the optical pickup 2 starts moving toward the target track obtained by the system controller 7. Here, in the track jump using the track counting method adopted in this embodiment, normally, the optical pickup 2 is moved to a target track by counting the number of tracks by a binarized signal from the RF amplifier 3. It is like this.

Specifically, when a track jump command is issued, the system controller 7 calculates the number of tracks from the address of the current position to the address of the target value. The binarized signal is composed of a pulse output each time the optical pickup 2 jumps over one track. When the optical pickup 2 starts to move in response to a track jump command, the system controller 7 counts the number of pulses of the input binarized signal, and the optical pickup is picked up until the number of pulses becomes equal to the calculated number of tracks. Move 2 When the track jump is completed, the servo loop is turned on and the data is read.

When the optical pickup 2 enters a different area,
The level detection circuit 15 detects the difference in the light receiving levels of the light receiving elements 25 and 26. Then, the level detection circuit 1
From 5, a switching request signal is output to the system controller 7 as an interrupt signal. In addition, the polarization detection circuit 16
As a result, it is detected whether or not the reproduction is performed by the polarized light, and the switching request signal is output to the system controller 7 as an interrupt signal.

In the system controller 7, the mode is switched to the interpolating clock mode immediately after receiving any one of the above switching request signals, and the interpolating signal generating circuit 14 is operated.
Pseudo tracks are counted by the interpolated clock signal output from. At this time, the pulse frequency of the interpolation clock signal is determined as follows.

This data MD device is provided with a high-speed jump that jumps over several hundred tracks or more by applying a voltage to the feed motor 10 and slides it, and a precision jump that jumps over several tracks while tracking control is performed. The accurate track search is performed by these. In other words, the track search is performed by combining the movement to the vicinity of the destination by the high speed jump and the movement to the final destination by the precision jump. Specifically, a high speed jump is used when jumping over 400 or more tracks. On the other hand, when jumping over 1 track and 10 tracks respectively, 1 jump and 10 jumps are prepared as precision jumps, and these are switched depending on the case.

The relationship between the speed change of the optical pickup 2 and the elapsed time in the high speed jump is as shown in FIG. That is, when the feed motor 10 accelerates the optical pickup 2 to reach a certain speed, the feed motor 10 holds the speed until the target track approaches and the brake is applied. Therefore, if the speed is increased too much, the braking time becomes long, while the braking in a short time causes the optical pickup 2 to vibrate, and it takes time to wait for its convergence. Such time loss leads to an increase in power consumption and a longer track search.

In the present data MD device, since the characteristics (maximum speed and acceleration) of the feed motor 10 are measured and stored in the buffer memory 5 when the disc 1 is inserted or the power is turned on, these measured values and the actual speed change. The optimum frequency is selected from. In practice, the optical pickup 2 most often passes the boundary at the maximum speed,
The frequency closest to the highest frequency of the binarized signal is selected.
It should be noted that the selected frequency is sampled in the buffer memory 5 at a frequency corresponding to each level of about 10 speeds when the characteristics of the feed motor 10 are measured.

On the other hand, the characteristic of the feed motor 10 is measured by P
For each of the IT area 1a and the GRV area 1b,
The track search is performed from an arbitrary position in a range accompanied by the movement of the optical pickup 2 at the maximum speed, and the average of the values measured at that time is stored in the buffer memory 5 as characteristic data. That is, the speed change and the maximum speed can be measured depending on how many MHz-order clocks are included in one pulse of the binarized signal.

The switching of the frequency of the interpolation clock signal according to the moving speed is performed according to the flow chart shown in FIG. First, in the signal processing circuit 4, the moving speed (cycle) of the optical pickup 2 is measured with about 10 pulses of the binarized signal (S1), and the average value thereof is calculated for each measurement (S2). At this time, the frequency closest to the average value is set in the interpolation signal generation circuit 14 every time the average value is calculated after the high speed jump is started. A frequency one level higher is reset, and if the vehicle is decelerating, a frequency one level lower than the speed average value at that time is reset.

Next, it is judged whether or not the optical pickup 2 has reached the boundary (S3). Here, if the boundary is not reached, the process returns to S2, and if the boundary is reached, it is determined whether fine adjustment of the frequency is necessary (S).
4). If fine adjustment is necessary, that process is executed (S
5) The frequency of the interpolated clock signal is set (S
6).

The fine adjustment of the frequency is specifically performed as follows. If the destination is close to the boundary, the optical pickup 2 will land at a position far from the boundary within the precision jump range, and the movement speed is set so that it will not land in the interpolation clock mode. The frequency is selected as described above. Conversely, if the destination is far from the boundary,
Since the optical pickup 2 passes the boundary at the maximum speed, the maximum frequency according to the maximum speed is selected.

If fine adjustment is not necessary in S4, the process is not executed, and the process proceeds to S6. Then, the interpolation clock signal is output (S7), and the switching process of the frequency of the interpolation clock signal is completed.

After shifting to the interpolation clock mode at the frequency determined as described above, each mode is switched. For example, PIT area 1a to GRV area 1b
When moving to, the laser power is increased four times, each set value of the tracking control is switched to the value of the GRV area 1b, and the peripheral LSI or the like is set. When all the switching is completed and several binarized signals are detected with the changed set value, the interpolation clock mode is completed and the normal track count is resumed.

The time required at this time is the sum of the laser power switching time, the gain adjustment time associated with the switching, the waiting time until the binary signal is detected and counting becomes possible, and the spindle mode switching time. And about 5 msec. The speed of the optical pickup 2 is about 40 kHz when the boundary is crossed at the maximum speed as shown in FIG.
If it is μm, it corresponds to about 200 tracks.

In a general MD device, the spindle servo control method is different between the PIT area 1a and the GRV area 1b. Therefore, in the case of the PIT area 1a, C
Similar to the D player, a servo signal is generated based on the read EFM signal, and the servo signal is given to the servo circuit 8 to perform CLV (Constant Linear Verocity) servo.
On the other hand, in the GRV area 1b, a servo signal is generated from the meandering cycle of a groove (Pre-Groove) previously engraved in the disk 1, and the servo signal is given to the servo circuit 8 to perform servo control. Therefore, when the spindle servo of the GRV area 1b is tried to be applied by the spindle servo of the PIT area 1a, runaway occurs in the rotation control of the spindle motor 11.

As shown in FIG. 6, when the target point (target track) O is near the boundary, the optical pickup 2 erroneously lands without crossing the boundary, and servo that does not match the area is performed. As a result, the above-mentioned runaway occurs. Therefore, in the present data MD device, the farthest point within the range where the precise jump after the high speed jump is possible is set as the temporary target point O ′ of the optical pickup 2. That is, a precision jump is performed after landing on the provisional target point O ′, so that the optical pickup 2 finally reaches the target point O.

When the PIT area 1a and the GRV area 1b have the same reflectance, the polarization detection circuit 16 detects the boundary. The track shift signal during the track search does not change in either area, but the reproduction system signal differs between the PIT area 1a and the GRV area 1b. At this time, in the polarization detection circuit 16, the two signals from the light receiving elements 25 and 26 are compared, and when the difference appears or when the difference disappears, it is judged as a boundary, and a switching request signal is sent to the system controller 7. , Mode switching is performed.

The operation after the mode is switched is the same as when detecting the change in reflectance. The time of the interpolation clock mode at this time is the total of the switching time of the spindle mode and the time until the detection of the binarized signal, which is about 2 msec. That is, when the boundary is crossed at the maximum speed, it corresponds to about 80 tracks. An outline of this series of operations is shown in the flowchart of FIG.

First, when the normal track counting is performed (S11), it is determined whether or not the target track is near the boundary (S12). At this time, if the target track is near the boundary, the landing point of the optical pickup 2 is changed (S13), and the boundary passing speed is calculated based on the speed characteristic of the feed motor 10 stored in the buffer memory 5. (S14). If the target track is not near the boundary in S12, the process proceeds to S14.

Next, the frequency is set in the interpolating signal generating circuit 14 (S15), and when a boundary is detected during the movement of the optical pickup 2 (S16), the mode shifts to the interpolating clock mode (S17). When the switching of each mode is completed (S18), the system controller 7 returns to the normal track count (S19), and the optical pickup 2 lands at the landing point (S20).

Plural PIT areas 1a on one disk
... and GRV area 1b ..., the control becomes complicated. In the disc 1 as shown in FIG. 2, the control in the case of track search across different areas is performed according to the procedure shown in FIG.

First, it is determined whether or not a boundary jump is to be performed (S21). If a boundary jump is to be performed, it is further determined whether or not the jump is a crossing of a plurality of boundaries (S22). If it is a multiple boundary jump, a track jump is executed (S23), and when a boundary is detected (S24), the interpolation clock mode is switched to (S25).

Next, mode switching is performed according to each area (S26), and it is further determined whether the optical pickup 2 has entered the area where the landing point is located, that is, has passed the boundary to that area. (S27). Here, if the passage is not determined, the process of S26 is performed again, but if the passage is determined, the mode of the landing area is switched (S28). After that, when the track deviation is detected (S29), the interpolation clock mode is released (S30), and the optical pickup 2 lands at the landing point (S31).

If it is not a boundary jump in S21, a normal jump process in the same area is performed (S32). If the jump is not a multi-boundary jump in S22, a jump over one boundary is performed between the PIT area 1a and the GRV area 1b (S33).

According to this control, in the area sandwiched between different areas, each setting is switched in each area in the interpolation clock mode. Since the boundary can be detected in the same manner as the method described above, the search can be performed by similarly performing the processing after entering the area with the landing point. The boundary address between the PIT area 1a and the GRV area 1b is a T address (not shown) of the innermost circumference of the disk 1 in advance.
Since it is described in the OC area, if the addresses of the jump start point and the jump end point are known, what kind of jump the jump is can be obtained. Therefore, the area can be determined when the boundary is detected.

The disk 1 used in this embodiment is as follows.
When a plurality of PIT regions and GRV regions are provided, the width of each region is limited. The size of each area is affected by the eccentricity of the disk due to the tracking servo being turned off during high-speed jumps, track count errors,
Considering landing near the boundary, it is considered necessary to have about 500 trucks. When the number is less than this number, it may be impossible to land on the target area.

[0077]

As described above, the track search device according to the first aspect of the present invention is a read-only area in which information is recorded depending on the presence or absence of pits and a recordable area where information can be recorded by the magneto-optical effect. A converging means for converging and irradiating a light beam onto a disk having a region; a moving means for moving the converging means so that the converging point of the light beam converged by the converging means crosses a track on the disk; Level detecting means for detecting the level of the reflected light reflected on the disk, polarization detecting means for detecting the polarization of the reflected light reflected by the light beam on the disk, and track deviation detection for detecting the positional deviation between the converging means and the track. Means, a binarizing means for binarizing the output signal from the track deviation detecting means, and the number of tracks crossed by the converging means. Counting means for counting the number of tracks, and the moving position of the converging means is detected based on the number of tracks counted by the counting means, and the converging means is used as a target track at an optimum speed corresponding to the position. And the movement control means for controlling the moving means to send to the track search start from one area of the recordable area or the read-only area of the disc, and the target track to be searched is in the other area of the disc. If present, when the level change of the reflected light is detected by the level detecting means or the polarization of the reflected light is detected by the polarization detecting means while the converging means is moving by the moving means. ,
In this configuration, a pseudo signal generating unit that pseudo-generates a binarized signal in place of the binarizing unit is provided.

As a result, even when the target track is located in a different region when the desired track is searched, the boundary between the two boundaries is detected, the binarized signal is artificially generated, and the track count is performed. Track search is not interrupted to switch modes. Therefore, if this track search device is adopted, the time required for track search can be shortened.

According to a second aspect of the present invention, there is provided a truck search apparatus according to the first aspect,
The movement control means changes the first destination of the converging means to a track near the target track according to the position of the target track, and moves the converging means from here to the target track. Since it is configured to control, the erroneous landing in the same area can be prevented, and while the converging means outputs the pseudo-generated binary signal signal by the pseudo signal generating means, the converging means. Can be prevented from reaching the target track. Therefore, if the present track search device is adopted, it is possible to prevent malfunctions in track search and perform stable track search.

According to a third aspect of the present invention, there is provided a track search device according to the first aspect, wherein:
Characteristic measuring means for measuring the speed characteristic of the moving means, speed detecting means for detecting the moving speed of the moving means, storage means for storing the speed characteristic measured by the characteristic measuring means, and the pseudo signal generating means. And a frequency correction means for correcting the frequency of the binarized signal output from the storage means in accordance with the moving speed detected by the speed detecting means based on the speed characteristic of the moving means stored in the storage means. .

Thus, the frequency of the binarized signal output from the pseudo signal generating means can be quickly set according to the actual moving speed of the converging means. Further, the difference from the track shift frequency is reduced, and the accuracy of track counting can be improved. Therefore, if the present track search device is adopted, the reliability of track search can be further improved.

According to a fourth aspect of the present invention, there is provided a track search device according to the first aspect, wherein:
When the switching of the operation mode of the disk device is completed in accordance with the recordable area or the reproduction-only area in which the target track of the converging means exists after the pseudo signal generating means starts to generate the binarized signal, the pseudo signal generating means is generated. It is a configuration including a stopping means for stopping the generation of the binarized signal from the means.

As a result, since the binarization signal can be generated by the binarization means after the generation of the binarization signal by the pseudo signal generation means is stopped, after the convergence means reaches the target track, It is possible to smoothly shift to disk control suitable for the area. Therefore, if this track search device is adopted, there is an effect that the time for track search can be shortened.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a configuration of a disc recorded and reproduced by the data MD device of FIG.

3 is a block diagram showing a configuration of an interpolation signal generating circuit in the data MD device of FIG.

4 is a graph showing the moving speed (frequency) with respect to the elapsed time from the movement start to the landing of the optical pickup that moves in a high-speed jump in the data MD device of FIG.

5 is a flowchart showing a procedure of switching the interpolation clock signal according to the moving speed of the optical pickup in the data MD device of FIG.

FIG. 6 is an explanatory diagram showing a jump path of the optical pickup when the target track is near the boundary in the data MD device of FIG. 1.

FIG. 7 is a flowchart showing a procedure for track search in the data MD device of FIG.

FIG. 8 is a flowchart showing a procedure of a boundary jump when a plurality of PIT areas and GRV areas are provided on the same disc.

9 is a perspective view showing a configuration of an optical pickup and an error amplifier commonly used in the data MD device of FIG. 1 and a conventional mini disk device.

10 is a waveform diagram showing a track shift signal detected by the optical pickup of FIG. 9 and a binarized signal obtained by binarizing the track shift signal.

FIG. 11 is an explanatory diagram showing a state where the PIT area of the disc is irradiated with laser light, a state where the PIT area of the PIT area is irradiated with laser light, and a state where the non-PIT portion of the PIT area is irradiated with laser light. .

FIG. 12 is a waveform diagram showing the outputs of two light receiving elements that receive the reflected light from the PIT region and the RF signal output from the error amplifier.

FIG. 13 shows a state in which a photomagnetization film in the GRV region of the disk is irradiated with laser light, a photomagnetization film whose magnetization direction is downward is irradiated with laser light, and a photomagnetization film whose magnetization direction is upward is laser. It is explanatory drawing which shows the state which the light was irradiated.

FIG. 14 is a waveform diagram showing the outputs of two light receiving elements that receive the reflected light from the GRV region and the RF signal output from the error amplifier.

[Explanation of symbols]

2 optical pickup (converging means) 3 RF amplifier (track deviation detecting means, binarizing means) 5 buffer memory (storage means) 7 system controller (counting means, movement control means, characteristic measuring means, speed detecting means, frequency correcting means) , Stop means 10 feed motor (moving means) 14 interpolation signal generating circuit (pseudo signal generating means) 15 level detecting circuit (level detecting means) 16 polarization detecting circuit (polarization detecting means)

Claims (4)

[Claims] 1. Converging means for converging and irradiating a light beam onto a disk having a recordable area where information can be recorded by the magneto-optical effect and a read-only area where information is recorded depending on the presence or absence of pits, and the converging means. Moving means for moving the converging means so that the converging point of the light beam converged by the means crosses the track on the disc; level detecting means for detecting the level of the reflected light reflected by the light beam onto the disc; Polarization detecting means for detecting the polarization of the reflected light reflected on the disk, track deviation detecting means for detecting the positional deviation between the converging means and the track, and binary for binarizing the output signal from the track deviation detecting means. Converting means, counting means for counting the number of tracks crossed by the converging means by the number of pulses of the binarized signal by the binarizing means, and counting by the counting means. A moving control means for detecting the moving position of the converging means on the basis of the number of tracks, and controlling the moving means so as to send the converging means to a target track at an optimum speed according to the position; Starts from either the recordable area or the reproduction-only area of the disc, and the target track to be searched exists in the other region of the disc, the converging means is moved by the moving means. In the meantime, when the level change of the reflected light is detected by the level detecting means or the polarization of the reflected light is detected by the polarization detecting means, the binarized signal is artificially replaced by the binarizing means. A track search device for a disk device, comprising: a pseudo signal generating means for generating the pseudo signal. 2. The movement control means changes the first destination of the converging means to a track near the target track according to the position of the target track, and moves the converging means from here to the target track. 2. The track search device for a disk device according to claim 1, wherein the moving means is controlled as described above. 3. Characteristic measuring means for measuring the speed characteristic of the moving means, speed detecting means for detecting the moving speed of the moving means, and storage means for storing the speed characteristic measured by the characteristic measuring means. Frequency correction means for correcting the frequency of the binarized signal output from the pseudo signal generating means based on the speed characteristic of the moving means stored in the storage means according to the moving speed detected by the speed detecting means. The track search device for a disk drive according to claim 1, further comprising: 4. When the switching of the operation mode of the disk device is completed in accordance with the recordable area or the reproduction-only area in which the target track of the converging means exists after the pseudo signal generating means starts to generate the binarized signal. 2. The track search device for a disk device according to claim 1, further comprising stop means for stopping the generation of the binarized signal from the pseudo signal generation means.