JPH05159318A - Tracking control device - Google Patents

Abstract

(57) [Abstract] [Purpose] In an optical recording / reproducing apparatus for recording / reproducing a disc having a recordable area (RW area) and a read-only area (ROM area), a gain of a tracking control system,
Alternatively, it is an object of the present invention to provide an apparatus having a high function capable of setting an offset in each area, always ensuring stable control performance, and supporting various discs. [Structure] Microcomputer 24 is a partial RO
The offset and gain of the tracking control system are adjusted in the RW area on the M disk, and the set values are stored in the built-in RAM. Next, the same adjustment is made in the ROM area, and the set value is stored in the built-in RAM. After that, when the RW area and the ROM area are searched for recording or reproduction, the offset value and the gain value on the RAM corresponding to the respective areas are reset. After searching the RW area and the ROM area, the offset and gain of the tracking control system are readjusted before recording and reproducing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in an optical recording / reproducing apparatus for optically recording a signal on a recording medium using a light source such as a laser or reproducing the signal on the recording medium. In particular, a part in which a rewrite area (RW area) and a read-only area (ROM area) coexist on the same recording medium.
The present invention relates to a tracking control device of an optical recording / reproducing device compatible with a Charl ROM disc.

[0002]

2. Description of the Related Art In recent years, a control system in an optical recording / reproducing apparatus has been developed and equipped with an automatic adjustment function and a learning function by the introduction of a microcomputer. In some conventional tracking control systems, for example, as disclosed in Japanese Patent Laid-Open No. 1-89034, the loop gain of the control system is automatically adjusted to an optimum value when the apparatus is started.

A conventional tracking control device will be described below. FIG. 9 is a block diagram showing the configuration of a conventional tracking control device. An optical beam 8 generated from a light source 1 such as a semiconductor laser is collimated by a coupling lens 2 and then reflected by a polarizing beam splitter 3 to obtain a wavelength λ / 4.
It passes through a plate 4 (where λ is the wavelength of the light beam), is converged by a converging lens 5, and is irradiated by a motor 6 onto a rotating disk 7. The reflected light of the light beam from the disk 7 passes through the converging lens 5, the λ / 4 plate 4 and the polarizing beam splitter 3, and is passed through the converging lens 9 to split the mirror 10.
Is divided into two directions. The divided light beam 11 is input to a photodetector 12 having a two-division structure. The outputs A and B of the photodetector 12 are amplified by the preamplifiers 13A and 13B, respectively, and then input to the differential amplifier 14, and a tracking shift signal can be obtained from the output of the differential amplifier 14.

The other optical beam 15 divided by the division mirror is input to a photodetector 16 having a two-division structure, and the difference output between the outputs C and D of the photodetector 16 is obtained. With this configuration, the focus beam shift signal can be obtained because the optical beam on the disk 7 is controlled so as to have a predetermined convergence state, but the description thereof is omitted because it is not directly related to the present invention. ..

For the track shift signal, a phase compensating circuit 17 for compensating the phase of the tracking control system, a synthesizing circuit 18 for adjusting the gain of the control system, and a gain adjusting circuit 1
9. Input to the tracking control element 21 via the drive circuit 20 for power amplification. Therefore, the tracking control element 21 is driven so that the optical beam on the disk 7 correctly scans the track.

Next, a method of adjusting the gain in this conventional tracking control device will be described.

When the power of the apparatus is turned on or the disk 7 is replaced, the disk 7 rotates, the light source 1 illuminates, and focus control and tracking control are applied.
The disturbance generating circuit 25 inputs a signal having a constant frequency to the synthesizing circuit 18 and applies disturbance to the control system. The disturbance signal and the response signal are converted by the AD converters 22 and 23 into the microcomputer 2
Take in 4. The microcomputer 24 arithmetically processes the two signals and measures the loop gain or the phase difference between the input disturbance signal and its response signal. The gain adjusting circuit 19 is operated according to the measured gain or phase difference, and the tracking control system is adjusted so as to have a predetermined loop gain.

[0008]

However, in the above-mentioned conventional technique, tellurium (Te) is formed on the same recording medium.
When performing reproduction or recording using a partial ROM disk in which a rewrite area (RW area) formed of a metal oxide film or a magnetic film such as a magnetic disk and a read-only area (ROM area) of uneven pit structure are mixed. In the ROM area, an optical beam is shaded by unevenness, and the signal quality such as S / N changes, so that a loop gain may differ from that in the RW area.

Therefore, for example, the loop gain is adjusted in the RW area and moved to the ROM area as it is, or RO
If the loop gain is adjusted in the M region and moved to the RW region as it is, there is a problem that the loop gain changes and the control performance deteriorates.

In addition, stabilizing search and jumping,
Further, in order to improve the vibration resistance, it is necessary to adjust the offset of the tracking control system so that the peak value of the track deviation signal at the time of crossing the track becomes symmetrical with respect to the target position for control. However, in the ROM area and the RW area, the symmetry of the track deviation signal, that is, the offset of the tracking control system may differ due to the influence of the inclination of the optical system, and the offset of the control system is adjusted in the RW area. When moving to the ROM area as it is or adjusting the offset of the control system in the ROM area and moving to the RW area as it is, the track deviation signal becomes asymmetric in one area, and the search performance and vibration resistance performance of the device deteriorate. Had.

The present invention solves the above problems. When automatically adjusting and learning the gain and offset of the control system, the offset or gain is set accurately in both the RW area and the ROM area, and is always set. It is an object of the present invention to provide a device having a high function capable of ensuring stable control performance and supporting various discs.

[0012]

In order to achieve this object, the tracking control device of the present invention comprises a converging means for converging and irradiating a recording medium provided with a recordable area and a read-only area with an optical beam. Moving means for moving the convergent point of the optical beam converged by the converging means so as to cross a track on the recording medium, and transmitted light transmitted through the recording medium by the optical beam or reflection reflected from the recording medium. Track deviation detecting means for generating a signal according to the positional relationship between the light beam of the recording medium and the track by light, and the moving means for driving the moving means in response to the signal of the track deviation detecting means Tracking control means for controlling so as to be positioned above and offset for measuring the offset of the tracking control system from the signal of the track deviation detection means when crossing one or more tracks. A first measuring means and an offset correcting means for correcting the offset measured by the offset measuring means, and measuring and correcting the offset in the recordable area and the reproduction-only area of the recording medium. is doing.

Further, another tracking control device of the present invention comprises a converging means for converging and irradiating a recording medium having a recordable area and a read-only area with an optical beam, and an optical beam converged by the converging means. Moving means for moving the convergence point of the beam across a track on the recording medium, and an optical beam of the recording medium by the transmitted light transmitted through the recording medium or the reflected light reflected by the recording medium. Track deviation detecting means for generating a signal corresponding to the positional relationship with the track, and tracking control for controlling the moving means by driving the moving means according to the signal of the track deviation detecting means so that the optical beam is positioned on the track. Means, a disturbance applying means for applying a disturbance signal to the tracking control means, the disturbance signal and a track deviation detection means signal when the disturbance signal is applied. And a gain adjustment unit for adjusting the gain of the tracking control unit according to the calculation result of the calculation unit, and a recordable area and a reproduction-only area of the recording medium. It has a second configuration in which the gain is adjusted by.

[0014]

According to the first and second configurations of the present invention, the offset and gain of the tracking control system are adjusted in each of the ROM area and the RW area when the apparatus is activated, and the adjusted values are stored. After that, when the tracks in each area are searched for recording and reproduction, the offset and gain adjustment values stored in the tracking OFF state are loaded and set. Alternatively, the gain and offset are readjusted after searching each area for recording / reproduction, so even if the control system status changes significantly between the ROM area and RW area due to the characteristics of the disk, it is possible to eliminate that effect. Becomes Therefore, it is possible to always ensure stable and highly accurate control performance.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tracking control device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a tracking control device according to an embodiment of the present invention. The same parts as those of the conventional tracking control device are designated by the same reference numerals, and the description thereof will be omitted.

The reflected light of the light beam 8 from the disk 7 is
The light passes through the converging lens 5, the λ / 4 plate 4 and the polarization beam splitter 3, and is divided by the dividing mirror 10 through the converging lens 9.
Divided into directions. The divided light beam 11 is input to a photodetector 12 having a two-division structure. The outputs A and B of the photodetector 12 are input to the differential amplifier 14 after being amplified by the preamplifiers 13A and 13B, respectively. The output signal of the differential amplifier 14 is applied to the microcomputer 2 in the synthesizing circuit 27.
4, a phase compensation circuit 17 that is combined with a signal output from a built-in DA converter (not shown) and that compensates the phase of the control system, a combining circuit 18 for gain adjustment, and a gain adjusting circuit 19. Pass through the tracking control element 21
Is input to the drive circuit 20 that drives the. The track shift signal output from the differential amplifier 14 is input to the microcomputer 24 via the AD converter 28.

The micro computer 24 takes in the maximum and minimum voltage values of the track deviation signal from the AD converter 28 and detects the magnitude thereof while the tracking control is OFF or during jumping. The offset of the tracking control system can be calculated by internally calculating the maximum and minimum voltage values. An appropriate offset voltage is output by a built-in DA converter (not shown) according to the calculated offset, and applied to the control system by the synthesizing circuit 27 so that the track deviation signal is adjusted to be symmetrical.

The microcomputer 24 also outputs a disturbance signal via a built-in DA converter, and the synthesizer circuit 18 applies the disturbance to the control system. The applied response signal of the disturbance is transmitted through the AD converter 22 to the microcomputer 2
It is entered in 4. From the disturbance signal and the response signal, the loop gain or phase of the control system is calculated by calculation, and a signal corresponding to the calculated value is output to the gain adjusting circuit 19, and the resistance value in the gain adjusting circuit 19 is switched to optimize. Set a proper gain.

The adjustment operation and learning operation in the case of the partial ROM will be described in more detail. FIG. 2 is a perspective view showing the structure of the partial ROM. Reference numeral 40 is a center hole for chucking, area 41 is an RW area in which recording and reproduction are possible, and area 42 is a read-only ROM area formed by concave and convex pits. These areas are arranged in the circumferential direction of the disk. It is divided. Reference numeral 43 is an adjustment track in the RW area, and 44 is an adjustment track in the ROM area, and signals of a single frequency are recorded in advance. Various information relating to this disc is recorded in the control tracks 45 and 46, and by reproducing this control track, address information such as a boundary between the RW area and the ROM area can be obtained.

When the power of the apparatus is turned on, the tracking control and the tracking control are activated at the time of starting the apparatus such as when the disk is exchanged, and after a track is retraced (hereinafter referred to as a still state), the RW area is set. Adjustment truck 4
3 is searched, and the offset adjusting operation is started.

There are various methods for adjusting the offset. FIG. 3 shows a track shift signal when the tracking control is turned off to measure the offset voltage.
FIG. 4 shows a track shift signal when jumping is performed to measure the offset voltage. In FIG. 3, P indicates the maximum value of the track deviation signal, and the voltage Vp indicates the voltage at that time. In the figure, M indicates the minimum value of the track deviation signal, and the voltage Vm indicates the voltage at that time. The microcomputer 24 executes tracking control OFF, takes in the voltages Vp and Vm as digital values via the AD converter 28, and internally executes calculation to calculate an offset value Voff to be corrected. Then, the correction value is output from the microcomputer 24 via a built-in DA converter (not shown) and adjusted. Further, as shown in FIG. 4, even if jumping is performed to measure the offset voltage and the maximum value P and the minimum value M at that time are obtained, the offset value Voff to be corrected can be similarly detected. The present invention can be applied to any offset adjustment method, and is not limited to that method.

After adjusting the offset by any of the above-mentioned methods, the gain adjusting operation is started. There are various methods for adjusting the gain as well as the offset, but the present invention is not limited by the method. In this embodiment, a method for directly obtaining the loop gain or the phase difference between the disturbance signal and its response signal from the disturbance signal and the response signal of the tracking control system will be described. When obtaining the phase difference between the loop gain or the disturbance signal and the response signal, a high-speed Fourier transform (hereinafter referred to as FFT) can be applied in order to reduce the influence of noise and improve the adjustment accuracy. The equations are as shown in (Equation 1) and (Equation 2).

[0024]

[Equation 1]

[0025]

[Equation 2]

From this result, the loop gain value P can be calculated by (Equation 3).

[0027]

[Equation 3]

The phase difference Q between the disturbance signal and its response signal can be calculated by (Equation 4).

[0029]

[Equation 4]

Based on the calculated loop gain value P or phase difference Q, a difference from the optimum gain to be adjusted is obtained, and a value corresponding to the difference is output to the gain adjusting circuit 19 to set the gain. The offset value and the gain value are stored in the RAM in the microcomputer 24.

When the adjustment in the RW area is completed, next RO
The adjustment track 44 in the M area is searched. In the ROM area, the offset and gain are adjusted and set in the same manner as in the case of the RW area described above, and the values are stored in the RAM in the microcomputer 24.

After the offset and gain are adjusted in each of the RW area and the ROM area as described above, a signal is recorded in the RW area or a recorded signal is reproduced from the ROM area to the RW area. When searching for a track
R when tracking control is OFF during search execution
The offset value and the gain value in the OM area are switched to the offset value and the gain value in the RW area, and then the tracking control is turned on. Similarly, when searching for a track in the ROM area from the RW area to reproduce a signal in the ROM area,
RW when tracking control is OFF during search execution
The offset value and the gain value of the area are switched to the offset value and the gain value of the ROM area, and then the tracking control is turned on. Therefore, since the offset and the gain are switched in the tracking OFF state, there is no influence of the step response due to the switching, and the set value can be smoothly changed.

The address in the still is the ROM area and R
When it is near the boundary of the W area, the truck is searched and moved by a jumping pig. In this case, the tracking control does not turn OFF in the hold state, so the ROM
When the difference between the offset and the gain in the region and the RW region is larger than the predetermined amount, the set value is switched stepwise after the movement, and when the difference is smaller than the predetermined amount, there is almost no influence of the switching, and therefore the set value is switched promptly after the movement.

By the above operation, learning of the offset and gain of the tracking control system can be realized, and the optimum tracking control state can be always secured. This series of microcomputer 24 and the entire device are controlled.
FIG. 5 shows a processing flow of a microcomputer (not shown) for the processing.

The first embodiment of the second embodiment of the present invention will be described below.
Similar to the embodiment described above, description will be made with reference to FIG. In the second embodiment, the offset and gain can be learned without adjusting the values in the RW area and the ROM area when the apparatus is activated and storing the values.

Tracking control and tracking control are activated when the apparatus is turned on or when the apparatus is started, such as when the disk is replaced, and after the still state is reached, the track to be recorded / reproduced is searched, and the offset is always applied to the track. , Readjustment of the gain is performed, and then recording and reproduction are performed. The method of adjusting the offset and the gain can be realized by the method described in the first embodiment, but the second method
The embodiment is not limited by these adjustment methods. As described above, according to the second embodiment, a more optimal tracking control state can be ensured during recording or reproduction, and state changes due to temperature characteristics can be absorbed. This configuration is shown in FIG.
This can be easily realized by changing the program of a microcomputer 24 (not shown) for controlling the controller 24 and the entire apparatus, especially when a high-speed automatic offset adjustment and automatic gain adjustment means are provided. It is facing.
The flow of this series of processing is shown in FIG.

Further, the present invention can be applied not only to the partial ROM disk as shown in FIG. 2 but also to disks having various structures.

For example, even when there are a plurality of RW areas 41 and ROM areas 42 of unspecified size alternately as shown in FIG. 7, it is possible to set the offset and gain of the areas finally reached during the search execution. Good.

When the RW area 41 and the ROM area 42 coexist in the radial direction of the disk as shown in FIG. 8, boundary signals 47 and 48 indicating boundaries are detected by the microcomputer 24 and the signals are detected. The offset and gain are adjusted and stored in each area in synchronization with. After that, the offset and the gain may be switched stepwise every time the boundary signal portions 47 and 48 are detected regardless of the state of recording, reproduction and retrieval.

[0040]

As described above, according to the present invention, the offset and gain for tracking control are set to the RW range and the R range.
Adjust each in the OM area and learn its value during the search. Alternatively, the gain and offset are readjusted after the search. Therefore, depending on the characteristics of the disk, ROM area and RW
Even if the state of the control system changes remarkably in the area, it is possible to eliminate the influence. Therefore, the accuracy is always high,
It is possible to provide a high-performance device capable of ensuring stable control performance, improving the reliability of the device, and supporting various disks such as multimedia.

[Brief description of drawings]

FIG. 1 is a block diagram of a tracking control device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a partial ROM disk used in the embodiment.

FIG. 3 is a waveform diagram of a track shift signal in a tracking control off state in the embodiment.

FIG. 4 is a waveform diagram of a track shift signal at the time of jumping in the example.

FIG. 5 is a flowchart showing a procedure for learning offset and gain adjustment in the embodiment.

FIG. 6 is a flowchart showing another procedure of offset and gain adjustment according to the embodiment.

FIG. 7 is a perspective view of a second partial ROM disk used in the embodiment.

FIG. 8 is a perspective view of a third partial ROM disk used in the embodiment.

FIG. 9 is a block diagram showing the configuration of a conventional tracking control device.

[Explanation of symbols]

 1 Light Source 2 Coupling Lens 3 Deflection Beam Splitter 4 λ / 4 Plate 5 Condenser Lens 6 Motor 7 Disk 8 Optical Beam 9 Condenser Lens 10 Split Mirror 11 Optical Beam 12 Photodetector 13a Preamplifier 13b Preamplifier 14 Differential amplifier 15 Optical beam 16 Photodetector 17 Phase compensation circuit 18 Combiner circuit 19 Gain adjusting circuit 20 Drive circuit 21 Tracking control element 22 AD converter 23 AD converter 24 Micro computer 25 Disturbance occurrence Circuit 27 Composite circuit 28 AD converter 40 Center hole 41 Recordable area (RW area) 42 Reproduction-only area (ROM area) 43 RW area adjustment track 44 ROM area adjustment track 45 Control track 46 Control track 46 47 boundary signal part 48 boundary signal part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuro Moriya 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A converging means for converging and irradiating a recording medium having a recordable area and a read-only area, and a converging point of the converging means for converging the optical beam is a track on the recording medium. A moving means for moving the optical beam across the recording medium and a transmitted light transmitted through the recording medium or a reflected light reflected from the recording medium generate a signal corresponding to the positional relationship between the optical beam and the track of the recording medium. A track deviation detecting means which is generated, a tracking control means which drives the moving means in response to a signal from the track deviation detecting means and controls the optical beam to be positioned on the track, and one or more tracks are crossed. Offset measuring means for measuring the offset of the tracking control system from the signal of the track deviation detecting means at the time, and the offset measured by the offset measuring means is corrected. An offset correcting means, wherein the recording area and the offset in the reproduction-only area of the recording medium is measured, tracking control device and correcting. 2. A first offset storage means for measuring an offset in a recordable area of a recording medium when the apparatus is activated, and storing a signal set in an offset correction means, and an offset in a reproduction-only area of the recording medium. A second offset storage means for storing the signal set in the offset correction means, and when performing the recording / reproducing operation in the recordable area, the signal of the first offset storage means is set in the offset correction means, Second when performing playback operation in the playback-only area
2. The tracking control device, wherein the signal of the offset storage means is set in the offset correction means. 3. A converging means for converging and irradiating a recording medium having a recordable area and a reproduction-only area, and a converging point of the converging light beam on the recording medium. A signal corresponding to the positional relationship between the optical beam of the recording medium and the track due to the moving means that moves across the track and the transmitted light transmitted by the optical beam on the recording medium or the reflected light reflected from the recording medium. A track deviation detecting means, a tracking control means for driving the moving means according to a signal from the track deviation detecting means to control the optical beam so that the optical beam is positioned on the track, and a disturbance to the tracking control means. Disturbance applying means for applying a signal, and computing means for computing the gain of the tracking control means on the basis of the disturbance signal and the signal of the track deviation detection means when the disturbance signal is applied. Depending on the calculation result of the calculating means,
A tracking control device comprising: a gain adjusting unit that adjusts a gain of the tracking control unit, and adjusting the gain in a recordable area and a reproduction-only area of the recording medium. 4. A first gain storage means for storing a signal set in the gain adjusting means when the gain is adjusted in the recordable area of the recording medium when the apparatus is activated, and a gain in the read-only area of the recording medium. A second gain storing means for storing a signal set in the gain adjusting means when adjusted, and when performing a recording / reproducing operation in a recordable area, the signal of the first gain storing means is sent to the gain adjusting means. A tracking control device characterized by setting the signal of the second gain storing means to the gain adjusting means when performing the setting and performing the reproducing operation in the reproduction exclusive area.