JP2895406B2 - Optical disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus for recording or reproducing information on an optical disk.

[0002]

2. Description of the Related Art In recent years, recording on a recordable optical disc such as a magneto-optical disc has a time axis attribute such as audio information. For example, Japanese Patent Application Laid-Open No. 1-224929
In the publication, E.
There has been proposed a recordable optical disc suitable for recording FM encoded information. This optical disk has a guide groove for recording information, and the guide groove is made to meander, and address information is recorded by FM-modulating the meandering frequency. By doing so, it is possible to detect which part of the disk is being scanned while having a continuous guide groove suitable for recording an EFM encoded signal. In the case of a recordable optical disc, the signal / recording / playback time is
In order to increase the noise ratio, those in which the width of the guide groove is wider than the distance between the grooves have been put to practical use.

When such a recordable optical disk is put into practical use, management information of the entire disk is recorded on the innermost periphery of the disk with uneven pits and user data is recorded on the outer periphery of the disk in order to improve usability. Is generally provided. As management information of the entire disc, UTOC (User Ta) which is table of contents information of user data is used.
The start address of an area for recording ble of contents, the start address of an area for recording user data, a recommended light intensity at the time of recording, and the like are recorded. Also,
The management information is stored in a predetermined location, so-called TOC (Table of Co
tents) area.

Here, when the width of the guide groove is wider than the distance between the grooves as described above, the area where the pits exist (hereinafter referred to as pit area) and the area where the guide grooves exist (hereinafter referred to as the groove area). Since the polarity of the tracking error signal to be detected is different between (1) and (2), it is necessary to invert the tracking error signal input to the tracking servo means. In a conventional optical disk device, as a method of detecting whether the position currently irradiated with a light beam is a pit region or a groove region, for example, a method of confirming whether address information can be read correctly is adopted. I was
That is, the address information is read once, and if the address information cannot be read, the polarity of the tracking error signal is inverted and read again.

[0005]

However, in the above-described optical disk device, when the address information cannot be read, a relatively long time is used in order to distinguish it from the case where the address information cannot be read due to scratches or dirt on the disk. It was necessary to confirm that the address information could not be read, and as a result, there was a problem that the operation of the optical disk device became slow.

On the other hand, in order to eliminate the time required to determine whether or not the address information can be read, a method of setting the polarity of the tracking error signal in advance during the movement of the optical head can be considered. However, when this method is used, it is premised that the light beam is located in an expected area at the time of applying the tracking servo. For example, in the case of accessing a groove area, first, the optical head is moved. It is necessary to take the method of moving by a predetermined time, setting the polarity of the tracking error signal while securely entering the area that seems to be the groove area, applying the tracking servo, and then gradually approaching the target address, Processing took time. Also, when pulling in the tracking servo, in order to lower the relative speed between the light beam and the information track, the relative movement direction may be obtained using a tracking error signal, and the light beam may be moved so as to lower the relative speed. However, when the polarity of the tracking error signal is reversed, the relative speed increases, and consequently, the time required to complete the pull-in of the tracking servo becomes long, or the pull-in cannot be performed.

In view of the foregoing, the present invention provides an optical disk apparatus capable of shortening the time required for access when performing recording and reproduction on an optical disk having a pit area and a groove area, and capable of reliably applying tracking servo. The purpose is to do.

[0008]

According to a first aspect of the present invention, there is provided an optical disk apparatus which irradiates an optical disk with a light beam through a light condensing means, converts reflected light from the optical disk into an electric signal, and outputs the signal. An optical head moving means for moving the optical head in the radial direction of the optical disk, an AS signal generating circuit for generating an AS signal corresponding to a change in intensity of reflected light from an output signal of the optical head, and detecting a high frequency component from the AS signal A high-frequency detection circuit for outputting a high-frequency detection signal, and a tracking error for generating a tracking error signal indicating a radial displacement of an optical disk between a light beam and a pit or a guide groove from an output signal of an optical head. a signal generating circuit, and a tracking error signal polarity switching circuit for outputting a signal obtained by inverting a tracking error signal or the polarity thereof, the tracking error signal polarity Move the condensing means based on the output signal of the replacement circuit in the radial direction of the optical disc, and tracking servo means for positioning the light beam on the pits or Draft <br/> groove, high-frequency detection signal from the high-frequency detecting circuit is output When the tracking error signal polarity switching circuit outputs a tracking error signal, and when the high frequency detection circuit does not output a high frequency detection signal, the tracking error signal polarity switching circuit outputs an inverted signal of the tracking error signal. System control means for controlling the polarity switching circuit , wherein the high-frequency detection circuit detects a signal having a predetermined frequency or higher.
The high-pass filter to be passed and the output of the high-pass filter
A binarizing means for binarizing the force and outputting it as a pulse;
Counting means for counting the number of pulses output by the digitizing means;
Reset means for resetting the counting means at regular time intervals;
The number of pulses output by the binarization means counted by the counting means and
The number of pulses output from the binarizing means by comparing with a predetermined value
Output high frequency detection signal when is greater than a predetermined value
And comparing means .

According to the second aspect of the present invention, there is provided a disk drive according to the first aspect.
An address information reproducing means for reproducing address information recorded on the optical disk from an output signal of the optical head, and a track for measuring the number of information tracks comprising pits and guide grooves traversed by the light beam of the optical head. Number control means, the system control means stops the operation of the focusing means by the tracking servo means when performing an access operation over the pit area and the groove area, and reads the light from the address information reproduced by the address information reproduction means. The number of information tracks to which the light beam of the head is to be moved is converted, and the optical head is moved by the optical head moving means until the converted number of information tracks matches the number of information tracks measured by the track number counting means. Tracking servo means and optical head movement And controlling the stage.

[0010] The disk device according to the third aspect is the first aspect of the invention.
Or in the disk device according to 2, wherein the system control means moves the light beam of the optical head from the pit area to the pit area by the optical head moving means, and moves from the groove area to the groove area. When the presence or absence of the high frequency detection signal from the high frequency detection circuit is inverted, the optical head moving means is controlled so as to stop or move the optical head in the opposite direction.

[0011]

An optical disk device according to a fourth aspect of the present invention provides
The optical disk device according to any one of 1, 2, and 3, further comprising a rotation number detecting means for detecting a rotation number of the optical disk, wherein the high frequency detection circuit detects a high frequency component when the rotation number of the optical disk detected by the rotation number detecting means is high. Higher,
If the rotation speed of the optical disk detected by the rotation speed detection means is low, the detection frequency band of the high frequency component is lowered.

[0013]

[0014]

According to the structure of the first aspect, the optical head converts the reflected light from the optical disk into an electric signal and outputs the electric signal.
A signal generation circuit generates an AS signal according to the intensity of the reflected light from the optical disk from the output signal of the optical head, and a high frequency detection circuit determines whether the AS signal contains a high frequency component. When the detection signal is output, the tracking error signal polarity switching circuit outputs a tracking error signal, and when the high frequency detection signal is not output from the high frequency detection circuit, the tracking error signal polarity switching circuit outputs an inverted signal of the tracking error signal. By controlling the tracking error signal polarity switching circuit by the system control means, when the AS signal contains a high frequency component, that is, when the position irradiated with the light beam is in the pit area, the tracking servo means has a tracking error signal. AS is input as it is
When the signal does not contain a high-frequency component, that is, when the position irradiated with the light beam is a groove area, an inverted signal of the tracking error signal is input to the tracking servo means. Therefore, when recording / reproducing on / from the optical disc having the pit area and the groove area, the tracking servo can be reliably performed, and the access can be speeded up. Furthermore, a high frequency detection circuit
In the above, after the AS signal has passed through a high-pass filter,
Whether the AS signal contains high frequency components
Is determined by the number of pulses within a predetermined time,
For example, several noises per rotation due to scratches
Even if mixed into the S signal, it can be neglected and is accurate
The presence or absence of a high frequency component can be detected at a high speed.

According to the second aspect of the present invention, when an access operation is performed over the pit area and the groove area, the operation of the focusing means by the tracking servo means is stopped, and the address reproduced by the address information reproducing means. The number of information tracks to which the light beam of the optical head is to be moved is converted from the information, and the optical head moving means is used until the converted number of information tracks matches the number of information tracks measured by the track number counting means. The optical head can be moved in a short time in a stable operation regardless of the polarity of the tracking error signal.

According to the third aspect of the present invention, when the light beam of the optical head is moved from the pit area to the pit area by the optical head moving means, and when the light beam is moved from the groove area to the groove area. When the presence or absence of the high-frequency detection signal from the high-frequency detection circuit is reversed, the optical head is stopped or moved in the opposite direction to quickly return when the light beam enters an area where it should not move, thereby achieving high speed. The access operation can be performed stably.

[0017]

According to the fourth aspect of the present invention, the high frequency detecting circuit increases the frequency band of the high frequency component when the rotation speed of the optical disk detected by the rotation speed detecting means is high, and the high frequency detecting circuit detects the high frequency component. If the rotation speed of the optical disc is low, the detection frequency band of the high-frequency component is lowered, so that even if the rotation speed of the optical disc changes, the high-frequency component included in the AS signal can be accurately detected, and erroneous detection can be eliminated.

[0019]

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an optical disk device according to one embodiment of the present invention. In FIG. 1, reference numeral 101 denotes an optical disc having a pit area and a groove area from the inner periphery, and the head address of the groove area is recorded in the pit area as management information. An optical head for converting the signal into a signal and outputting the signal; a lens (condensing means) for condensing the light beam; a focus actuator for moving the lens in a direction perpendicular to the surface of the optical disk 101; And a built-in tracking actuator.

Reference numeral 103 denotes a tracking error signal generating circuit for generating a tracking error signal from an electric signal output from the optical head 102; 104, a tracking error signal inverting circuit for inverting the polarity of the tracking error signal; A tracking error switching circuit for switching a signal to be output; a tracking loop filter for applying phase compensation to an input signal; and outputting the tracking signal; a kick pulse generation circuit for generating a kick pulse for moving a lens in the radial direction of the optical disc; A tracking drive signal switching circuit for switching a signal applied to the actuator; 109
Turns ON the tracking actuator drive /
This is a tracking drive switch that is turned off.
The tracking error signal inversion circuit 104 and the tracking error switching circuit 105 constitute a tracking error signal polarity switching circuit, and the tracking loop filter 106 and the tracking actuator constitute tracking servo means.

Reference numeral 110 denotes a tracking error switching circuit 10.
A traverse error detection circuit 111 for extracting and outputting a low-frequency component of the output of the output circuit 5;
Is a traverse loop filter that performs phase compensation on the signal output from the optical disk 101, 112 is a forced drive signal generation circuit that generates a forced drive signal that moves the optical head 102 in the radial direction of the optical disc 101, and 113 is the traverse moving mechanism 11.
A traverse drive signal switching circuit 114 for switching a signal to be applied to the optical disk 101;
And a traverse drive switch 115 for turning on / off the drive of the traverse movement mechanism 114. The traverse loop filter 111, the forced drive signal generation circuit 112 and the traverse moving mechanism 114 constitute an optical head moving means.

A focus error signal generating circuit 116 generates a focus error signal from a signal output from the optical head 102, a focus loop filter 117 performs phase compensation on the focus error signal and outputs the focus error signal, and 118 turns ON / OFF the driving of the focus actuator. This is a focus drive switch that is turned off. 119 is a management information reproducing circuit (including arrangement information reproducing means) for reproducing management information from a signal output from the optical head 102, and 120 is an address reproducing circuit (address information reproducing circuit) for reproducing address information from a signal output from the optical head 102. Means, AS (All Su) indicating the total amount of reflected light from the signal output from the optical head 102.
m; an AS signal generation circuit for generating a signal
Reference numeral 22 denotes a high-frequency detection circuit that determines whether or not the AS signal contains a high-frequency component, and sets the high-frequency detection signal to a high level (output) if it is included.

Reference numeral 123 denotes a signal input from the management information reproducing circuit 119, the address reproducing circuit 120, the high frequency detecting circuit 122, and the track number counting circuit 124.
A system controller (system control unit) that controls the tracking drive signal switching circuit 108, the tracking drive switch 109, the forced drive signal generation circuit 112, the traverse drive signal switch circuit 113, the traverse drive switch 115, and the focus drive switch 118. Reference numeral 124 denotes a track number counting circuit (track number counting means) that counts the number of information tracks traversed by the light beam by counting the number of zero cross points at the right of the signal output from the tracking error switching circuit 105.

The operation of the first embodiment of the optical disk apparatus thus configured will be described with reference to the flowchart shown in FIG. When performing recording and playback,
First, in order to reproduce the management information recorded in the TOC area, the system controller 123 drives the traverse moving mechanism 114 by turning down the traverse drive signal switching circuit 113 toward the forced drive signal generation circuit 112 and closing the traverse drive switch 115. Then, the optical head 102 is moved to the TOC area on the inner peripheral portion (step 301).
The movement to the TOC area is performed by providing a switch (not shown) that is turned on when the optical head 102 comes to the position of the TOC area, and opening the traverse drive switch 115 when this switch is turned on. .

When the movement of the optical head 102 to the TOC area is completed, the system controller 123 turns on the focus drive switch 118 to execute the focus servo loop including the focus actuator, the focus error signal generation circuit 116, and the focus loop filter 117. close. Next, the tracking error switching circuit 1
05 to the tracking error signal generation circuit 103 side,
The tracking drive signal switching circuit 108 is moved to the tracking loop filter 106 side, and the tracking drive switch 109 is closed to perform tracking servo. Further, the traverse drive signal switching circuit 113 is moved to the traverse loop filter 111 side, and the traverse drive switch 115 Is closed, a traverse servo using the low frequency component of the tracking error signal output from the traverse error detection circuit 110 as an error signal is performed.

When focus, tracking, and traverse servos are applied, the light beam output from the optical head 102 follows the pits, and the optical head 102
The management information written in 1 is output as an electric signal. The management information reproducing circuit 119 receives the electric signal, reproduces the management information, and outputs it to the system controller 123.
The system controller 123 obtains the address of the UTOC from the management information (step 302).
Access the beginning of C.

First, since the address reproducing circuit 120 outputs the address information recorded so as to be superimposed on the management information, the system controller 123 outputs the address of the position where the current light beam is irradiated from the address reproducing circuit 120. Obtain (step 303), this address and UTOC
Is converted to the number of information tracks (step 304). Next, the tracking drive switch 109 and the traverse drive switch 115 are opened, and the tracking and traverse servos are released. Subsequently, the traverse drive signal switching circuit 113 is switched to the forced drive signal generation circuit 1.
12, the traverse drive switch 115 is closed, and the optical head 102 is moved in the outer peripheral direction (step 305).

The track number counting circuit 124 counts the number of tracks traversed by the light beam from the tracking error signal, and the system controller 123 compares the number of traverses output by the track number counting circuit 124 with the previously calculated target number of movements. If they match, the traverse drive switch 115 is opened. Next, it is monitored whether or not the high-frequency detection signal is low level (L) (step 306). To the tracking drive signal switching circuit 108 and the tracking loop filter 106
Side and close the tracking drive switch 109.
Further, the traverse drive signal switching circuit 113 is moved to the traverse loop filter 111, and the traverse drive switch 115 is closed (step 308). Here, when the high frequency detection signal is at a high level (H), the traverse drive switch 115 is closed for a predetermined time and the optical head 1
02 is moved to the outer periphery (step 307), and it is confirmed again whether or not the high frequency detection signal is at the low level (step 306).

Next, the system controller 123
The address information of the position where the light beam is currently scanned output from the address reproducing circuit 120 is input (step 30).
9) Compare with UTOC start address (step 3)
10). If they match, the UTOC information is read as it is (step 311), and recording / reproducing of the optical disk is performed according to this information (step 312). If the addresses are different, it is determined whether or not the address difference is large (step 313). If the address is large, the traverse moving mechanism 114 is again activated by the forced drive signal generation circuit 112.
(Step 314). If the difference is small, the tracking drive signal switching circuit 108 is tilted toward the kick pulse generation circuit 107, and the light beam is moved by the tracking actuator (Step 31).
5) The address is read again (step 309), and it is determined whether the addresses match again (step 31).
0).

Here, the high frequency detection circuit 122 will be described in detail. FIG. 2 is a block diagram illustrating a configuration (first configuration) of the high-frequency detection circuit 122. 201 is a high-pass filter, 202 is a binarization circuit (binarization means), 203
Is a counter (counting means) for counting the number of rising edges of the output of the binarization circuit 202;
Oscillator (reset means) for periodically resetting 03,
Reference numeral 205 denotes a comparator (comparing means) for comparing the output of the counter 203 with a comparison value 206.

A signal output from the AS signal generation circuit 121 in the groove area when the tracking servo is off.
The S signal has a sinusoidal waveform that rises and falls at the speed at which the light beam crosses the information track. This is because when the light beam crosses between the guide grooves, light is diffracted by so-called land portions between the grooves, and the amount of reflected light is reduced. In this case, the frequency of the AS signal is several hundred Hz to several tens KHz. On the other hand, in the pit area, a signal of a high frequency component is superimposed on a signal when crossing the information track by the pit. For example, when an EFM signal is recorded in pits, the frequency of the pits is 200 kHz to 700 kHz.
If the cutoff frequency of the high-pass filter 201 is 50 KHz, high frequency components due to pits can be extracted. The signal thus obtained is input to the binarization circuit 202, binarized, and input to the clock of the counter 203. The counter 203 counts the number of rising edges of the input signal,
5 is output. The comparator 205 compares the input with the comparison value 206, for example, 40 counts, and sets the output to a high level when the output of the counter 203 exceeds 40 counts. This output is the high frequency detection signal. The oscillator 204 outputs a pulse signal every 100 μs,
Is cleared (reset). Thus, the high-frequency detection circuit 122 sets the high-frequency detection signal to a high level when the AS signal includes a component of 400 KHz or more.

As described above, in the first embodiment, when accessing the groove area from the pit area, the optical head 102
After the movement of
By confirming that the S signal does not contain a high-frequency component, inverting the polarity of the tracking error signal and applying tracking servo and traverse servo, the variation in the drive sensitivity of the traverse moving mechanism 114 and the counting of the number of traversing tracks are performed. Irrespective of the error of the optical disk or the magnitude of the eccentricity of the optical disk, it is possible to reliably move the optical head 102 to the groove area with a small amount of movement and read out or write information recorded in the groove area such as UTOC. A possible optical disk device can be realized. In particular, when recording in the guide groove is performed by a magneto-optical method, the recorded signal component does not appear in the AS signal even if recording is performed in the guide groove, so this method is very effective.

The high-frequency detection circuit 122 described in the first embodiment outputs the AS signal to the high-pass filter 201.
And then digitized to determine whether the AS signal contains high frequency components. In this method, since the judgment is made based on the count value of a predetermined time, for example, 1
Even if about several noises are mixed in the rotation of the AS signal, the influence can be substantially ignored, so that the presence or absence of high frequency components can be detected at high speed. In addition, FG (Fr
A rotation speed detecting means such as an equality generator circuit for detecting the rotation speed of the optical disk 101 is prepared, and the comparison value 206 is changed in accordance with the rotation speed. Detection can be performed. For example, if the rotation speed of the spindle motor is high, the frequency of traversing the information track due to eccentricity increases. Therefore, by increasing the comparison value 206 accordingly, it is possible to eliminate erroneous detection. Even when the rotation speed is low, the comparison value 20
Since it is possible to detect high frequency components due to pits by reducing the size of the optical disk 1, for example, the optical disk 1
It is possible to determine the pit area and the groove area even immediately after the start of the rotation of 01.

In the first embodiment, the tracking servo is removed, the number of zero-cross points of the tracking error signal is counted, and the traverse moving mechanism 114 is used instead of moving the light beam using a kick pulse. Although the method of moving the optical head 102 is used, this is very effective in the case of access that crosses the pit area and the groove area as in this case. Since the output timing of the kick pulse is determined by observing the change in the tracking error signal, if the polarity changes in the middle, the kick operation becomes unstable. On the other hand, in the method used in this embodiment, even if the polarity of the tracking error signal changes during access, the operation does not become unstable. In addition, the counting by the track number counting circuit 124 does not increase the error much even if the polarity of the tracking error signal is reversed in the middle, and requires a smaller moving amount as compared with the case where the optical head 102 is moved for a fixed time. Optical head 102
Can be completed.

In the first embodiment, the case where the pit area is accessed to the groove area has been described.
Similar effects can be obtained when the groove area is accessed from the groove area. Conversely, the same effect can be obtained when accessing the pit area from the groove area or when accessing the pit area from the pit area. However, in this case, after the movement of the optical head 102 is completed,
After confirming that the high frequency detection signal has become high level, the tracking servo is turned on.

In the first embodiment, the optical head 102
After the movement of the optical head 102 was completed, the high-frequency detection signal was determined, and the setting of the tracking error switching circuit 105 was performed.
The setting of the tracking error switching circuit 105 may be changed before the movement of the optical head 102 is completed. With such a method, the access operation can be further speeded up.

Next, a second embodiment will be described. Second
The embodiment of the present invention aims to reduce the time required for completing access when, for example, user data is recorded and the table of contents information of the recorded user data is additionally recorded in the UTOC. FIG. 4 is a flowchart of the second embodiment. Here, the operation will be described on the assumption that the recording of the user data is completed and the UTOC area is accessed.

The settings of the circuits controlled by the system controller 123 at the time when the recording of the user data is completed are as follows. The tracking error switching circuit 105 is on the tracking error signal inverting circuit 104 side, the tracking drive signal switching circuit 108 is on the tracking loop filter 106 side, the tracking drive switch 109 is closed, the traverse drive signal switching circuit 113 is on the traverse loop filter 111 side, and the traverse drive switch. 115 is closed, and the focus drive switch 118 is closed.

First, the system controller 123 stores the address of the position where the current light beam is radiated (the position where the recording of the user data has been completed) into the address reproducing circuit 120.
, The target number of movements is calculated from the difference from the head address of the UTOC area read in advance (step 401). Next, the tracking drive switch 109 is opened, the traverse drive signal switching circuit 113 is turned to the forced drive signal generation circuit 112 side, and access is started (step 402). The optical head 102 moves inward in accordance with the output of the forced drive signal generation circuit 112, and the tracking error signal in the form of a sine wave is
Enter 4 The track number counting circuit 124 counts and outputs the number of zero cross points of the input signal rising to the right. The system controller 123 compares the count value output from the track number counting circuit 124 with the calculated number of accesses and monitors whether they match (step 403). If they match, traverse drive switch 1
15, the movement of the optical head 102 is stopped, the tracking drive switch 109 is closed to perform tracking servo, the traverse drive signal switching circuit 113 is turned down to the traverse loop filter 111 side, and the traverse drive switch 115 is closed. Thus, the light beam scans the guide groove, and the address information can be read. The system controller 123 takes in the address information output from the address reproduction circuit 120 (step 405), and compares it with the target start address of the UTOC area (step 406). If the addresses match, the access operation ends, and the UTOC is recorded.

Now, returning to step 403, if the output of the track number counting circuit 124 does not match the target number of movements, the system controller 123 checks whether the high frequency detection signal is at a high level (step 40).
7). This is a check as to whether the optical head 102 is in the pit area. By performing this, the following two advantages are obtained. The first is speeding up access. Since both the area for recording user data and the UTOC area are inside the groove area, the fact that the high frequency detection signal is at a high level means that the count value of the track number counting circuit 124 reaches the calculated target movement number before reaching the calculated target movement number. It means that the vehicle has passed the target position. Therefore, at this point, the movement is interrupted and the access is restarted, whereby the access can be speeded up. Second, the tracking servo is stabilized at the end of access. First
As described in the embodiment, the polarity of the tracking error signal is inverted in the pit area and the groove area. For this reason,
The tracking servo is turned on with the intention of accessing the groove area while the optical head 102 has entered the pit area.
However, the servo is not correctly applied, and information such as an address cannot be read correctly. When the high frequency detection signal becomes high level, the access is stopped and the optical head 1 is stopped.
If 02 is moved in the outer circumferential direction until the high frequency detection signal becomes low level (steps 408 and 409), the information recorded on the optical disk 101 can be read out without switching of the tracking error switching circuit 105.

At step 407, it is determined whether or not the high frequency detection signal is at a high level. If not, the process returns to step 403 to check the output of the track number counting circuit 124. And repeats a loop of monitoring the high frequency detection signal. When it is detected that the high-frequency detection signal has become high level, the system controller 123 inverts the polarity of the forced drive signal output from the forced drive signal generation circuit 112 and moves the optical head 102 to the outer side (step 4).
08). At the same time, the high frequency detection signal is monitored (step 409), and the optical head 102 is moved in the outer peripheral direction while the high frequency detection signal is at the high level. When the high-frequency detection signal becomes low level, the system controller 123 opens the traverse drive switch 115, closes the tracking drive switch 109 and performs tracking servo,
The traverse drive signal switching circuit 113 is turned to the traverse loop filter side, the traverse drive switch 115 is closed, and traverse servo is applied. Then, the address information output from the address reproducing circuit 120 is read (step 405), and it is determined whether or not this address matches the start address of the UTOC (step 406).

As described above, in the second embodiment, the high frequency detection signal is monitored while the optical head 102 is moving, and the optical head 102 is accessed when the groove area is accessed.
Detects that has moved to the pit area, stops access at the same time as detection, and forcibly moves the optical head 102 to the groove area, enabling high-speed and stable access operation I have to.

In the second embodiment, access from the groove area to the groove area has been described. However, the same can be applied to access from the pit area to the pit area. In this case, the optical head 10
It is determined whether or not the high-frequency detection signal is at a low level during the movement of the optical head 102.
May be moved inward until the high-frequency detection signal becomes high level.

Next, a third embodiment will be described. In the above-described first and second embodiments, the improvement of the operation at the time of access has been described. However, in the third embodiment, focus, tracking, and traverse servo are applied (here, for convenience, the “normal trace state”). I will call it)
For example, the light beam moves across the pit area and the groove area due to external vibration, a signal from the optical disk being unreadable due to scratches or dirt near the boundary between the pit area and the groove area, and the like. A description will be given of the stabilization of the operation in the case where the error has occurred.

As described above, when the width of the guide groove is larger than the distance between the grooves, the polarity of the tracking error signal in the pit area and the groove area is inverted.
Further, the gain of the tracking error signal is lower in the pit area than in the groove area because reflected light is reduced by the pit. When the light beam moves from the pit area to the groove area in the normal tracing state, there is a risk that the tracking servo deviates due to these factors, and the traverse servo performed using the low frequency component of the tracking error signal runs away. If the traverse servo is released, the optical head 102 moves to the limit of the movable range of the traverse moving mechanism, and it takes time to return the optical head 102 to the original position, and an abnormal sound is generated at the time of runaway, so that the user is inconvenient. There is a problem in that a pleasant feeling is given and power consumption increases.

The operation of the optical disk device according to the third embodiment will be described. FIG. 5 is a flowchart of the operation of the system controller 123 according to the third embodiment. here,
A case will be described as an example in which the management information of the entire disc recorded in the TOC area is read and the groove area is approached. First, the system controller 123 reads the management information from the optical head 102.
Is moved to the TOC area (step 501), and focus, tracking, and traverse servo are applied (steps 502, 503, and 504). Up to this point, the same operation as in the first embodiment is performed. Normal trace state, TOC
When the management information can be read from the area, the system controller 123 starts receiving the management information from the management information reproducing circuit 119 (step 505). The contents of the received management information are checked to determine whether or not the reading has been completed (step 506). When the reading has been completed, the traverse drive switch 115 is opened to stop the traverse servo (step 508), and the tracking is performed. The drive switch 109 is opened to stop the tracking servo (Step 509), and the focus drive switch 118 is opened to stop the focus servo (Step 510).

If it is determined in step 506 that the reading of the management information has not been completed, the high-frequency detection signal is read and it is determined whether or not the signal is at the high level (step 507). If the level is high, it is determined that the light beam is in the pit area, and the process returns to step 505 to continue reading the management information. If it is not high level,
Since it is considered that the light beam has moved to the groove area, the traverse drive switch 115 is opened simultaneously with the detection, the driving of the traverse moving mechanism 114 is stopped, and the movement of the optical head 102 is stopped (step 508). Thereafter, the servo is stopped in the order of tracking servo and focus servo (steps 509 and 510).

As described above, in the third embodiment, the traverse servo is stopped by monitoring the high-frequency detection signal while reading the pit area and stopping the traverse servo when it is determined that the light beam has approached the groove area. It is possible to prevent abnormal noise and increase in power consumption due to servo runaway, and to shorten the time required to return to the state before runaway. Further, in this method, since it is possible to directly detect from the AS signal, it is possible to operate at a higher speed than, for example, a method of monitoring the continuity of the address read from the optical disk.

In the third embodiment, the case where the light beam approaches the groove area during reproduction of the pit area has been described. However, the same effect can be obtained when recording or reproduction is performed in the groove area. be able to. For example, when recording / reproducing near the innermost circumference of the groove area, if the light beam moves to the inner circumference side due to an external impact, it is detected that the high frequency detection signal has become high level. Alternatively, the traverse servo may be stopped.
Further, the same effect can be obtained with an optical disc having a pit area provided outside the groove area.

In the first, second, and third embodiments, the system controller 123 monitors the high-frequency detection signal. However, the level of the high-frequency component in the AS signal changes at the same frequency as the tracking error signal. Therefore, in order to increase the detection accuracy, the high-frequency detection signal may be checked a plurality of times at predetermined time intervals. Next, in a fourth embodiment, a method for preventing runaway of the traverse servo when the light beam moves over the pit area and the groove area without using the high frequency detection signal will be described.

The operation of the optical disk device according to the fourth embodiment will be described. FIG. 6 is a flowchart of the operation of the system controller 123 according to the fourth embodiment. here,
A case will be described as an example in which the management information of the entire disc recorded in the TOC area is read and the groove area is approached. In the fourth embodiment, it is assumed that the management information includes the arrangement information of the pit area and the groove area, that is, the address of the boundary between the pit area and the groove area (here, the start address of the UTOC area).

First, the system controller 123 moves the optical head 102 to the TOC area to read out management information (step 601), and performs focus, tracking, and traverse servo (steps 602 and 6).
03, 604). Up to this point, the same operation as in the first embodiment is performed. When the normal trace state is set and the management information can be read from the TOC area, the system controller 123 starts receiving the management information from the management information reproducing circuit 119 (step 605). The content of the received management information is checked to determine whether or not the reading has been completed (step 606). If the reading has been completed, the traverse drive switch 115, the tracking drive switch 109, and the focus drive switch 118 are opened. , Traverse, tracking, focus servo
FF is performed (steps 607, 608, 609).

If the reading has not been completed, the current address information output from the address reproducing circuit 120 is received (step 610), and the received current address information is compared with the previously received head address of the UTOC area. (Step 611). If the difference between the two is, for example, about 100 or more apart in terms of the number of tracks, the flow returns to step 605 to continue reading the management information,
If the number is less than 100, the traverse drive switch 115 is opened to stop the operation of the traverse moving mechanism 114 (step 612). Normally, the movable range of the tracking actuator built in the optical head 102 is several hundred μm. Therefore, when the track pitch is 1 to 2 μm as in a compact disk or the like, only the tracking actuator is used even if the eccentricity is taken into consideration. Tracking of about 100 tracks is possible. By keeping the traverse drive switch 115 open, even if the light beam moves from the pit area to the groove area and the tracking servo deviates, the optical head 102 does not move due to runaway of the traverse servo.

As described above, in the fourth embodiment, the current address information is obtained during the reproduction of the pit area, and this is compared with the start address of the UTOC area which is the arrangement information of the pit area and the groove area. When the drive of the traverse moving mechanism 114 is stopped at a stage near the boundary between the area and the groove area, the traverse servo runs away at the boundary between the pit area and the groove area, and the optical head 102 moves farther from the current position. Alternatively, it is possible to prevent generation of abnormal noise and increase in power consumption due to runaway of the traverse servo.

As the arrangement information of the pit area and the groove area, the last address of the TOC area may be used. Although the fourth embodiment has described the case where the groove area is provided outside the pit area, the present invention can be applied to the case where an optical disc having the pit area provided outside the groove area is used. It is possible.

Next, an example in which the high-frequency detection circuit 122 is simplified will be described. FIG. 7 shows a high-frequency detection circuit 122.
It is a block diagram which shows the 2nd structure of. 701, a high-pass filter for extracting high-frequency components from the AS signal;
Reference numeral 703 denotes a peak hold circuit that detects and holds the peak of the signal output from the high-pass filter 701, and reference numeral 703 denotes a comparator that compares the output level of the peak hold circuit 702 with a predetermined voltage.

For example, an EFM signal is recorded in the form of a pit, and the cutoff frequency of the high-pass filter 701 is set to 50.
If the frequency is set to about KHz, a signal corresponding to the amplitude of the signal component due to the pit in the AS signal is output to the output of the peak hold circuit 702. By comparing this signal with a predetermined voltage, it is possible to detect whether or not the AS signal contains a frequency component due to a pit. The comparator 703 compares the output of the peak hold circuit 702 with a predetermined voltage, and outputs a high level when the output of the peak hold circuit 702 is large. The output of the comparator 703 is used as a high frequency detection signal.

In the description of the high-frequency detection circuit 122, information that has been subjected to EFM modulation has been described as an example of information to be recorded in the pit area, but information using another modulation method may be recorded. .

[0060]

As described above, according to the present invention, when recording / reproducing is performed on an optical disk having a pit area and a groove area, tracking servo can be performed reliably, and the access operation can be performed at high speed. Optical disk device can be realized.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a first configuration of a high-frequency detection circuit according to the embodiment of the present invention.

FIG. 3 is a flowchart showing an operation procedure of the optical disc device in the first embodiment of the present invention.

FIG. 4 is a flowchart showing an operation procedure of the optical disc device according to the second embodiment of the present invention.

FIG. 5 is a flowchart showing an operation procedure of the optical disc device according to the third embodiment of the present invention.

FIG. 6 is a flowchart showing an operation procedure of an optical disc device according to a fourth embodiment of the present invention.

FIG. 7 is a block diagram showing a second configuration of the high-frequency detection circuit according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 101 optical disk 102 optical head 103 tracking error signal generating circuit 104 tracking error signal inverting circuit 105 tracking error switching circuit 106 tracking loop filter 107 kick pulse generating circuit 110 traverse error detecting circuit 111 traverse loop filter 112 forced driving signal generating circuit 114 traverse moving mechanism 119 management information reproduction circuit 120 address reproduction circuit 121 AS signal generation circuit 122 high frequency detection circuit 123 system controller 201 high-pass filter 202 binarization circuit 203 counter 204 oscillator 205 comparator 701 high-pass filter 702 peak hold circuit 703 comparator

Continuation of front page (56) References JP-A-6-150337 (JP, A) JP-A-3-130972 (JP, A) JP-A-5-67329 (JP, A) JP-A-63-167430 (JP) JP-A-3-194770 (JP, A) JP-A-4-265578 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 7/085 G11B 7/09 G11B 7/095

Claims (4)

(57) [Claims] 1. An optical disc apparatus for recording / reproducing on / from an optical disc having a pit area in which information is recorded by pits and a groove area in which a guide groove for recording information is carved, wherein the optical disc has a Irradiating a light beam via light means,
An optical head that converts the reflected light from the optical disc into an electric signal and outputs the electric signal; an optical head moving unit that moves the optical head in a radial direction of the optical disc; and an intensity of the reflected light from the output signal of the optical head. An AS signal generation circuit that generates an AS signal according to a change; a high frequency detection circuit that outputs a high frequency detection signal when a high frequency component is detected from the AS signal; a light beam and the pit from an output signal of the optical head
Or, a tracking error signal generation circuit that generates a tracking error signal indicating the amount of radial deviation of the optical disc from the guide groove, a tracking error signal polarity switching circuit that outputs the tracking error signal or a signal whose polarity is inverted, A tracking servo means for moving the light condensing means in the radial direction of the optical disk based on an output signal of the tracking error signal polarity switching circuit to position the light beam in the pit or the guide groove; and a high frequency detection signal from the high frequency detection circuit. Is output, the tracking error signal polarity switching circuit outputs the tracking error signal, and when the high frequency detection signal is not output from the high frequency detection circuit, the tracking error signal polarity switching circuit outputs the inverted signal of the tracking error signal. To output the track And a system control means for controlling the grayed error signal polarity switching circuit, the high frequency detection circuit, the high-pass filter which passes or more signal predetermined frequency
And binarize the output of the high-pass filter as a pulse
Binarizing means for outputting, and counting means for counting the number of pulses output by the binarizing means
When the reset hands for resetting said counting means at predetermined time intervals
Stages, and the number of pulses output by the binarizing means counted by the counting means.
The number of data and a predetermined value are compared, and the binarization means outputs
High frequency detection signal when the number of pulses
An optical disk device comprising: a comparing unit that outputs a signal . 2. An address information reproducing means for reproducing address information recorded on an optical disk from an output signal of an optical head, and a track for measuring the number of information tracks comprising the pits and guide grooves traversed by the light beam of the optical head. A number counting unit, wherein the system control unit stops the operation of the focusing unit by the tracking servo unit and performs the reproduction by the address information reproducing unit when performing an access operation over the pit area and the groove area. The number of information tracks to which the light beam of the optical head should be moved is converted from the obtained address information, and the movement of the optical head is continued until the converted number of information tracks matches the number of information tracks measured by the track number counting means. Means for moving the optical head by means of the tracking servo. The optical disk apparatus according to claim 1, wherein the controlling the stage and the optical head moving means. 3. The high-frequency detection circuit is provided when the optical head moving means moves the light beam of the optical head from the pit area to the pit area and when the optical head moves from the groove area to the groove area. 3. The optical disk device according to claim 1, wherein the optical head moving means is controlled so as to stop or move the optical head in the opposite direction when the presence or absence of the high frequency detection signal from the optical head is reversed. 4. A high-frequency detection circuit for detecting the number of rotations of the optical disk, wherein the high-frequency detection circuit increases the detection frequency band of a high-frequency component if the number of rotations of the optical disk detected by the rotation number detection means is high. 4. The optical disc device according to claim 1, wherein the detection frequency band of the high-frequency component is lowered when the rotation speed of the optical disk detected by the rotation speed detecting means is low.