JP2842141B2 - 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 device,
In particular, the present invention relates to an optical disk device that records signals on both a recording track of a concave portion and a recording track of a convex portion formed by a guide groove on a disk.

[0002]

2. Description of the Related Art In recent years, optical disk devices capable of recording and reproducing information signals such as video or audio signals have been actively developed. In a recordable optical disk device, a guide groove is preliminarily carved on a substrate of the optical disk to form a track. The recording or reproduction of the information signal is performed by focusing the laser beam on the flat portion of the concave portion or the convex portion of the track. In a general optical disk device currently on the market, an information signal is usually recorded on only one of a concave portion and a convex portion, and the other is a guard band that separates adjacent tracks.

FIG. 10 is an enlarged perspective view of an optical disk used in such a conventional optical disk device. In FIG. 1, reference numeral 201 denotes a recording layer, which is formed of, for example, a phase change material. 202 is a recording pit, and 203 is a beam spot of a laser beam. 204 is a concave portion formed as a guide groove, 205 is a convex portion between the guide grooves, and the concave portion 204 is wider than the convex portion 205. 206
Are pre-pits which form identification signals indicating position information on the disk. Further, the transparent disk substrate through which the incident light is transmitted is omitted in FIG. As described above, the recording track formed by the concave portion includes an identification signal area in which the identification signal is recorded in advance by the pre-pit 206, and the recording pit 2
02 is divided into a main information signal area where an information signal is recorded.

A conventional optical disk device using this optical disk will be described with reference to the drawings.

FIG. 11 is a block diagram of such a conventional optical disk device. In the figure, reference numeral 207 denotes an optical disk, and 208 denotes a recording track, which is the recess 204 in this case. 210 is a semiconductor laser, 211 is a semiconductor laser 21
Numeral 0 denotes a collimating lens for converting the emitted laser light into parallel light, 212 denotes a half mirror placed on the light beam, and 213 denotes the parallel light passing through the half mirror 212.
7 is an objective lens that condenses light on the recording surface on the reference numeral 7. Reference numeral 214 denotes a photodetector that receives reflected light from the optical disk 207 through the objective lens 213 and the half mirror 212, and is divided into two parts in parallel with the track direction of the disk to obtain a tracking error signal. 214b
Consists of An actuator 215 supports the objective lens 213. The actuator 215 is attached to a head base (not shown), and forms an optical head 216. 217 is a differential amplifier to which the detection signals output from the light receiving units 214a and 214b are input, and 218 is a low-pass filter (LPF) to which the difference signal output from the differential amplifier 217 is input. 219, an output signal of the LPF 218 and a control signal L1 from a first system controller 232 to be described later are input, and a drive circuit 220 and a traverse control circuit 2 to be described later
26 is a tracking control circuit that outputs a tracking control signal to 26. A drive circuit 220 outputs a drive current to the actuator 215. 221 is a light receiving unit 214a
, And a high-pass filter (HPF) 222 that receives the sum signal from the addition amplifier 221 and outputs the high-frequency component to a first waveform shaping circuit 223 described later. 223 is a first waveform shaping circuit that receives the high-frequency component of the sum signal from the HPF 222 and outputs a digital signal to a reproduction signal processing circuit 224 and a first address reproduction circuit 225 described later. A reproduction signal processing circuit that outputs an information signal to the output terminal 233. 225
Is a first address reproduction circuit that receives a digital signal from the first waveform shaping circuit 223 and outputs address data to a first system controller 232 described later. 226 is a first system controller 23 to be described later.
2, a traverse control circuit that outputs a drive current to a traverse motor 227 described later,
A traverse motor 27 moves the optical head 216 in the radial direction of the optical disk 207. Reference numeral 228 denotes a spindle motor for rotating the optical disk 207. 229
Is an information signal such as sound input from the external input terminal 230, and outputs a recording signal to a laser drive circuit 23 to be described later.
1 and a recording signal processing circuit 231 for outputting to the first
The laser drive circuit receives a control signal L3 from the system controller 232 and a recording signal from the recording signal processing circuit 229, and inputs a driving current to the semiconductor laser 210. Reference numeral 232 denotes a first system controller that outputs control signals L1 to L3 to the tracking control circuit 219, the traverse control circuit 226, and the recording signal processing circuit 229, and receives an address signal from the first address reproduction circuit 225.

[0006] The operation of the conventional optical disk device configured as described above will be described with reference to FIG.

[0007] The laser beam emitted from the semiconductor laser 210 is collimated by a collimator lens 211 and converged on an optical disk 207 by an objective lens 213 via a beam splitter 212. Optical disk 2
The light beam reflected by 07 has information of the recording track 208 by diffraction, and is guided to the photodetector 214 by the beam splitter 212 via the objective lens 213. The light receiving units 214a and 214b convert the change in the light amount distribution of the incident light beam into an electric signal, and output the electric signal to the differential amplifier 217 and the addition amplifier 221 respectively. The differential amplifier 217 converts the respective input currents into an IV signal, and then takes a differential to output the differential as a push-pull signal. L
The PF 218 extracts a low-frequency component from the push-pull signal and outputs it to the tracking control circuit 219 as a tracking error signal. The tracking control circuit 219 outputs a tracking control signal to the drive circuit 220 according to the level of the input tracking error signal, and the drive circuit 220 supplies a drive current to the actuator 215 according to the signal to record the objective lens 213. Control the position across the track. Thereby, the beam spot scans the convex portion 205 correctly. On the other hand, the position of the objective lens 213 is controlled by a focus control circuit (not shown) in a direction perpendicular to the disk surface so that the beam spot is correctly focused on the disk.

On the other hand, the addition amplifier 221 is connected to the light receiving section 214a.
And the output current of 214b is subjected to IV conversion and then added,
The signal is output to the HPF 222 as a sum signal. The HPF 222 cuts unnecessary low-frequency components from the sum signal, passes the reproduction signal and the identification signal, which are main information signals, as analog waveforms, and outputs the analog signals to the first waveform shaping circuit 223. The first waveform shaping circuit 223 performs data slicing on the main information signal and the address signal of the analog waveform with a fixed threshold to form a pulse waveform, and outputs the pulse waveform to the reproduction signal processing circuit 224 and the first address reproduction circuit 225. The reproduction signal processing circuit 224 demodulates the input digital main information signal, and thereafter performs processing such as error correction to produce a sound signal or the like as an audio signal.
Output to 3. The first address reproduction circuit 225 demodulates the input digital identification signal and outputs address data to the first system controller 232. That is, as a result of the beam spot 203 scanning over the recording pits 202, a playback signal is input to the playback signal processing circuit 224, and as a result of scanning over the pre-pits 206, an identification signal is input to the first address playback circuit 225. The first system controller 232 determines whether the current light beam is at a desired address based on the address data.

The traverse control circuit 226 outputs a drive current to the traverse motor 227 according to a control signal L2 from the first system controller 232 when the optical head is moved, and moves the optical head 216 to a target track. At this time, the tracking control circuit 219 also outputs a control signal L1 from the first system controller 232.
Temporarily suspends the tracking servo. Also,
At the time of normal reproduction, the traverse motor 227 is driven according to the low frequency component of the tracking error signal input from the tracking control circuit 219, and the optical head 216 is gradually moved in the radial direction along with the progress of reproduction.

The recording signal processing circuit 229 adds an error correction code or the like to the audio signal or the like input from the external input terminal 230 at the time of recording and outputs it to the laser drive circuit 231 as an encoded recording signal. The first system controller 232 controls the laser driving circuit 2 by the control signal L3.
31 is set to the recording mode, the laser drive circuit 231
Modulates a drive current applied to the semiconductor laser 210 according to a recording signal. Thus, the intensity of the beam spot irradiated on the optical disk 207 changes according to the recording signal, and the recording pit 202 is formed. On the other hand, at the time of reproduction, the laser drive circuit 231 is set to the reproduction mode by the control signal L3, and controls the drive current so that the semiconductor laser 210 emits light at a constant intensity. This makes it possible to detect recording pits and pre-pits on the recording track.

While the above operations are being performed, the spindle motor 228 rotates the optical disk 207 at a constant angular velocity.

Here, conventionally, in order to increase the recording capacity of the optical disk 207, the width of the convex portion 205 is narrowed to reduce the track interval. However, if the track interval is reduced, the diffraction angle of the light reflected by the concave portion 204 becomes large, so that there is a problem that a tracking error signal for causing the beam spot 203 to follow the track with high accuracy is reduced. Further, since there is a limit even if the track interval is reduced only by the width of the convex portion 205, the width of the concave portion 204 must be narrowed. This causes a problem that the amplitude of the reproduced signal decreases because the recording pit 202 becomes thin.

On the other hand, as disclosed in Japanese Patent Publication No. 63-57859, there is a technique of increasing the track density by recording information signals in both the concave portion 204 and the convex portion 205.

FIG. 12 is an enlarged perspective view of such an optical disk. 10, reference numeral 201 denotes a recording layer, 202 denotes a recording pit, and 203 denotes a beam spot of a laser beam. The same components as those described with reference to FIG. 10 are denoted by the same reference numerals. 240 is a concave portion formed as a guide groove, and 241 is a convex portion between the guide grooves. As shown in the figure, the widths of the concave portion 240 and the convex portion 241 are substantially equal. Reference numeral 242 denotes a pre-pit, which is formed in both the concave portion 240 and the convex portion 241 and is inscribed at the head of each sector of both recording tracks as an identification signal indicating positional information on the optical disk.

In this optical disk, recording pit 2
As shown in the figure, the reference numeral 02 is formed in both the concave portion 240 and the convex portion 241. The period of the guide groove is the same as that of the optical disk of FIG. 10, but the interval between the recording pit rows is halved. This doubles the recording capacity of the optical disk.
Hereinafter, both the concave portion 240 and the convex portion 241 in such an optical disc are referred to as recording tracks in the sense that the recording pits 202 are formed.

The recording / reproducing operation of the optical disk device for this optical disk is basically performed in the same manner as the optical disk device shown in FIG. However, as described in the above-mentioned Japanese Patent Publication No. 63-57859, the tracking error signal of the beam spot 203 is different between when the beam spot 203 is scanning over the convex portion 241 and when the beam spot 203 is scanning over the concave portion 240. The polarity needs to be reversed. This is because the LPF 218 and the tracking control circuit 2 in FIG.
19, this can be realized by inserting an inverting amplifier whose ON / OFF can be controlled.

[0017]

However, in the optical disk shown in FIG. 12, in order to obtain position information at an arbitrary position on a recording track of a concave portion and a recording track of a convex portion, an identification signal such as a prepit is recorded on both recording tracks. There is a problem that the number of manufacturing steps must be increased in comparison with the optical disc shown in FIG.

The present invention solves the above-mentioned problem, and it is possible to obtain position information on both recording tracks without forming identification signals such as address information on both the recording tracks of the concave portions and the recording tracks of the convex portions. It is an object of the present invention to provide an optical disk and an optical disk device that are capable of operating.

[0019]

In order to achieve the above object, an optical disk according to the present invention comprises a spiral or concentrically formed concave and convex portion formed on a disk as recording tracks, and stores positional information on the disk. An optical disc in which an identification signal is recorded in advance, and an information signal is recorded by using a change in a local optical constant or a physical shape due to irradiation of a light beam, and the identification signal is recorded by modulating the width of a concave portion. In addition, in at least a part of the area of the optical disk, the head position of the identification signal is made to match between adjacent recording tracks.

Further, as the position information in the identification signal, a gray code that changes by one bit at the time of counting up is used.

Also, an optical disk apparatus of the present invention irradiates the optical disk with a light beam, receives the reflected light, converts the reflected light into an electric signal and outputs it as a read signal, A polarity inverting means for inverting and outputting the polarity of the read signal during scanning on the identification signal in the recording track of the projection, an identification signal reading means for decoding the identification signal from the reading output by the polarity inversion means, and an optical head Information signal reading means for decoding an information signal from the read signal output by the information recording means, an information signal recording means for recording the information signal on the optical disk, a disk rotating means for rotating the optical disk, and a light beam for emitting a recording track or projection on a concave portion of the optical disk. And tracking control means for positioning the recording control unit on a recording track.

Further, the optical disk apparatus of the present invention detects tracking error detection means for detecting the deviation of the light amount distribution of the light beam reflected from the optical disk in the radial direction of the disk, and outputs a tracking error signal in response to the detection. A first detection pulse is output when the tracking error signal becomes larger than a predetermined positive threshold value while scanning the identification signal in the recording track of the convex portion, and the tracking error signal becomes a predetermined negative value. Detecting means for outputting a second detection pulse when the value is smaller than the threshold value, wherein the identification signal reading means decodes from the read signal while the light beam is scanning on the identification signal in the recording track of the convex portion. The identification signal is corrected in accordance with the first and second detection pulses.

[0023]

With the configuration described above, the optical disc of the present invention can
If the width of the recording track of the concave portion on the disk is modulated according to the identification signal, and the leading position of the identification signal is matched between the recording tracks of the adjacent concave portions, the recording track of the convex portion is opposite to the adjacent concave portions. Receives width modulation of polarity. As a result, if the identification signal is the same between adjacent tracks, it is detected as the intensity of the reflected light even on the recording track of the convex portion.

Further, a gray code is used as a part of the identification signal to be recorded on the recording track of the concave portion, and even if the identification signal has a different value between the adjacent tracks, the recording track of the convex portion sandwiched therebetween is used. The reading error of the identification signal in is only one bit at most, and it is possible to easily estimate a correct identification signal value.

In the optical disk apparatus of the present invention, the polarity inversion means inverts the reproduction signal only when the light beam is on the recording track having the convex portion, and the identification signal reading means decodes the identification signal based on the inverted signal.

Further, the tracking error detecting means detects the deviation of the light quantity distribution of the light beam reflected from the optical disk in the radial direction of the disk and outputs a tracking error signal, and the error bit detecting means detects that the light beam has a convex part. During scanning on the identification signal in the recording track, a first detection pulse is output when the tracking error signal becomes larger than a predetermined positive threshold, and the tracking error signal becomes higher than a predetermined negative threshold. When it becomes smaller, the second detection pulse is output to the identification signal reading means, and the identification signal reading means corrects the gray code in the reproduced signal in accordance with the first and second detection pulses, thereby providing correct identification. Output a signal.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical disk according to an embodiment of the present invention will be described below with reference to the drawings. In the present embodiment, it is assumed that a phase change type recording material that performs recording by changing the actual reflectance is used as a recordable / reproducible optical disk, and the rotation speed of the optical disk is controlled at a constant peripheral velocity (CAV). : Constant Angular Vel
A description will be given of a case in which an ocity (abbreviation of constant angular velocity) is used.

FIG. 1 is an enlarged plan view of a recording surface of an optical disk according to a first embodiment of the present invention. In the figure, 1
Numerals 3 and 3 denote spiral concave portions, which also serve as guide grooves for tracking control. 2 is a convex part between the concave parts. Both the concave portions and the convex portions are arranged at a pitch Tp. Information signals are recorded in both the main information signal areas of these concave portions and convex portions. The width of the concave portion in this region is W _O =
Tp / 2, but in the identification signal area, the width of the concave portion depends on the binary value of the identification signal. When the identification signal is 1, W _H ,
When 0 and _{W L (W H> W L} ), taking two widths. That is, the width of the concave portion is modulated by the identification signal. When the beam spot traces the identification signal area of the concave portion, the difference in width changes the amount of reflected light, so that the identification signal can be read. Here, when the width of the concave portion is W _O , W _H and W _L , the reflected light amounts are I _O and I _H , respectively.
And I _L , I _H > I _O > I _L. In the present embodiment, CAV is used, and the identification signal area is arranged so that the displacement points of the identification signal coincide between adjacent tracks as shown in FIG. Thus, for the convex portion, the width of the convex portion when the width of the recess on both sides are W _H is W _L (A point in FIG. 1), W _H (in FIG point B) when the neighboring is W _L, one is the other is W _O when the W _H in W _L (C point in the drawing). In this manner, the width of the convex portion is also modulated according to the width modulation pattern of the concave portion on both sides.

Next, the recording format of the optical disk of the present embodiment in which the identification signal is recorded by the above-described width modulation of the concave portion will be described. FIG. 2 is an explanatory diagram of a recording format in a recording track of a concave portion. One track is divided into a plurality of sectors. By using CAV, each sector is radially arranged in the disk radial direction. One sector includes an identification signal area and a main information signal area. The identification signal area includes blocks of a sector mark, a synchronization pattern, an address mark, a track number, a sector number, and a concavo-convex mark, and is recorded by a change in the width of the concave portion as described above. The function of each block is as follows. (1) Sector mark: indicates the start of each sector. (2) Synchronization pattern: A clock for reproducing address data is generated. (3) Address mark: indicates that address data starts. (4) Track number, sector number: indicates address data. (5) Concavo-convex mark: Indicates whether the recording track is a concave portion or a convex portion. Among them, the sector mark, synchronization pattern and address mark are the same in all sectors. Sectors adjacent in the radial direction are given the same sector number. In this embodiment, a gray code is used as a track number, and only one bit changes between adjacent track numbers. This bit is hereinafter referred to as a shift bit. The width of the concave / convex mark is set to _WH in the concave portion.

On the other hand, the recording format of the convex portion is basically the same as that of the concave portion. However, the configuration is such that the identification signal is obtained by utilizing the fact that the width of the projection is changed by modulating the width of the concave portion on both sides according to the identification signal.

That is, in the block of the sector mark, the pattern for synchronization, the address mark and the sector number, the binary pattern is the same between the adjacent concave portions.
The widths of the protrusions in these blocks are exactly the inverse of the patterns of the recesses on both sides. Therefore, by inverting the polarity of the reproduction signal obtained from the change in the amount of reflected light when the beam spot traces this portion, it is possible to read in the same manner as in the case of the recording track in the concave portion. Since the gray code is used in the block with the track number, the bits other than the shift bits have the same pattern in the concave portions on both sides. Therefore, it can be read like other blocks. Since the shift bits are wide W _L and W _H of the recess on both sides, the width of the projections W _O, and the reflected light amount becomes approximately equal to I _O. If a change in the amount of reflected light is detected by a ternary detector, I _O , I _H, and I _L can be identified, so that the position of the shift bit can be detected. If the track number of the convex portion is defined to be the same as the track number of the concave portion in contact with the inner peripheral side, the track number of the convex portion can be obtained from the binary pattern other than the reproduced shift bit and the position of the shift bit. it can. This is because two track numbers can be obtained from the binary pattern other than the shift bits, and the smaller number among them is equal to the track number of the convex portion to be obtained as the gray code. This will be described with reference to the drawings.

FIGS. 3A and 3B are explanatory diagrams, wherein FIG. 3A shows a gray code of track numbers of two adjacent concave portions 1 and 2, FIG. 3B shows an enlarged view of a track width-modulated according to the gray code, and FIG. Is a waveform diagram of a reproduced digital signal from each track, and (d) is a binary pattern obtained from a signal obtained by inverting the reproduced digital signal from the convex portion 1. In FIG. 9C, when the convex portion 1 is reproduced, the shift bit is H
However, since it is not L, an error occurs and the track number becomes unknown as it is. However, since the gray code changes only one bit between adjacent numbers, if the shift bit is set to H in the binary pattern obtained in FIG. For example, it becomes equal to the gray code of the concave portion 2. According to the above-described definition of the track number, if an algorithm that always takes the smaller one of the two codes is used, a correct track number can always be obtained even in the convex portion.

[0033] In block of concave and convex marks, since the width of the recess on both sides is W _H, the width automatically becomes W _L in the convex portion, thereby making it possible to distinguish between concave and convex portions.

An apparatus for manufacturing the optical disk of this embodiment will be briefly described with reference to the drawings. FIG. 4 is a block diagram showing the configuration. A radiation beam source 30 such as a laser light source emits a radiation beam 31 having sufficient energy. The radiation beam 31 passes through a light intensity modulator 32, a light deflector 33, and a mirror prism 34, and is converged on a minute radiation beam spot by an objective lens 35. For example, a photoresist layer is applied as a radiation beam sensing layer 37 to a record carrier 36 such as an optical disk substrate. The gate signal generator 39 outputs a gate pulse equal to the length of the identification signal at a predetermined period to the identification signal generator 40 in synchronization with the rotation phase signal output from the motor 38 for rotating the record carrier 36. The identification signal generator 40 outputs the identification signal to the modulator 42 and the intensity switching signal generator 44 when the gate pulse from the gate signal generator 39 is input. The oscillator 41 outputs a carrier signal having a frequency sufficiently higher than the bit clock of the identification signal to the modulator 42. The modulator 42 includes the oscillator 4
The carrier signal from No. 1 is AM-modulated with the identification signal and output to the amplifier 43 as a modulated signal. The optical deflector 33 changes the angle of the radiation beam 31 by an extremely small angle in accordance with the drive signal input via the amplifier 43 so that the minute beam spot is displaced in the radial direction on the record carrier.

FIG. 5 is a trajectory of a minute beam spot displaced according to the drive signal. As shown in the figure, in the main information signal area, the amplitude of the displacement of the beam spot in the disk radial direction is W _O , and in the identification signal area, the amplitude takes W _H and W _L according to the binary value of the identification signal. Here, the modulator 42
In, the amplitude of the modulation signal output during the period when the identification signal is not input is set such that the displacement amplitude becomes W _O in the main information signal area. In the modulator 42 and the amplifier 43, the amplitude of the drive signal and the AM modulation degree are set so that each amplitude value becomes a predetermined value, and errors due to the intensity distribution of the minute beam spot are adjusted.

The intensity switching signal generator 44 outputs a three-stage intensity switching signal via the amplifier 45 to the optical intensity modulator 3 in accordance with the binary value of the identification signal and the presence / absence of the input of the identification signal.
Output to 2. The light intensity modulator 32 switches the intensity of the radiation beam 31 according to the input intensity switching signal. The switching person, taking into account the speed of radial displacement of the small beam spot, is strongest when the displacement amplitude W _H of the aforementioned minute beam spot, the weakest when W _L, W
_{In the case of O} , it is an intermediate value between them. Thereby, the sensing layer 37 can be irradiated with a beam at a substantially constant intensity per unit time, so that unevenness in the exposure state can be eliminated. After the exposure is completed, the disk substrate is completed through steps such as etching, transfer, and molding.

The light deflector 33 can be constituted by a so-called acousto-optic deflector. FIG. 6 shows an acousto-optic device used as such a deflector 33. In this acousto-optic device, an acousto-optic cell 50 is provided with two electromechanical transducers 51 and 52 connected to terminals 55 and 56. When an electric signal is supplied to the terminals 55 and 56, the cell 5
An acoustic wave of a certain frequency is generated in the medium 0, for example, in the glass. As a result, Bragg refraction occurs in the medium, so that the radiation beam 53 partially becomes the sub beam 54 at the angle α.
Is deflected. The angle α is proportional to the frequency of the supplied electric signal.

As described above, according to the optical disk of the present embodiment, in the CAV control disk, by modulating the width of the concave portion according to the binary value of the identification signal, the width of the convex portion is also modulated. Can also obtain an identification signal. Further, by using the gray code as the track number to be recorded as the identification signal in the concave portion, it is possible to obtain an accurate track number even in the convex portion.

Next, a first embodiment of an optical disk apparatus using the optical disk of the present invention will be described with reference to the drawings.
This embodiment has a feature in a method of reproducing an identification signal recorded in advance on an optical disk. Therefore, only the relevant parts are illustrated and described here, and the other parts are the same as those shown in FIG. It is assumed that this is the same as the optical disc of FIG.

FIG. 7 is a block diagram showing a configuration of a main part of the optical disk device according to the first embodiment. In FIG.
4a and 214b are light receiving portions of a photodetector, 217 is a differential amplifier, 218 is a low-pass filter (LPF), 221 is an addition amplifier, 222 is a high-pass filter (HPF), 22
3 is a first waveform shaping circuit, 224 is a reproduction signal processing circuit,
Reference numeral 233 denotes an output terminal, which is basically the same as the components of the conventional optical disk apparatus shown in FIG. 11, and therefore, is denoted by the same reference numerals as in the conventional example, and detailed description is omitted.

The configuration of a portion different from that of FIG. 11 will be described. Reference numeral 60 denotes a tracking error signal output from the LPF 218, a control signal L4 input from a second system controller 67 described later, and a tracking control circuit 219.
1 is a first polarity inversion circuit that outputs a tracking error signal. Here, as for the polarity of the tracking control, when the tracking error signal is input from the differential amplifier 217 to the tracking control circuit 219 with the same polarity, the tracking pull-in is performed on the recording track in the concave portion. Reference numeral 61 denotes a high-frequency component of the sum signal from the HPF 222 and a control signal L from a second system controller 67 described later.
4 is a second polarity inverting circuit that inputs a signal 4 and outputs a high-frequency signal to a second waveform shaping circuit 62 described later. Reference numeral 62 denotes a high-frequency signal input from the second polarity inversion circuit 61 and converts a digital reproduction signal into a second address reproduction circuit 63 described later.
And a second waveform shaping circuit 63 for outputting to the third address reproducing circuit 65, the digital reproduced signal is inputted from the second waveform shaping circuit 62, and an address calculating circuit 6 which will be described later.
Reference numeral 6 denotes a second address reproducing circuit for outputting the first address data. Reference numeral 64 denotes a third waveform shaping circuit which receives a high-frequency component of the sum signal from the HPF 222 and outputs a detection pulse signal to a third address reproducing circuit 65 which will be described later. Reference numeral 65 denotes a second waveform shaping circuit 62 and a third waveform shaping. The digital reproduction signal is inputted from the circuit 64 and the address calculation circuit 6
Reference numeral 6 denotes a third address reproducing circuit for outputting the second address data. 66 receives the address data from the second address reproduction circuit 63 and the third address reproduction circuit 65, and the control signal L4 from the second system controller 67, and sends the third address data to the second system controller 67. This is an address calculation circuit to output.
67 is a first polarity inversion circuit 60, a second polarity inversion circuit 6
1 and a control signal L4 to the address calculation circuit 66,
This is a second system controller that receives third address data from the address calculation circuit 66 and performs the same operation as the first system controller 232 in the conventional optical disk device shown in FIG.

The operation of the optical disk apparatus of the present embodiment configured as described above will be described with reference to the drawings focusing on the operation of reading the identification signal, which is a feature of the present invention.

First, when reading the identification signal of the recording track in the concave portion, the second system controller 67 disables the first polarity inversion circuit 60 and the second polarity inversion circuit 61 through the control signal L4. The first polarity inversion circuit 60 includes the light receiving units 214a and 214b, the differential amplifier 21
7 and the tracking error signal input through the LPF 218 is output to the tracking control circuit 219 as it is. Thereby, the beam spot irradiated on the optical disk traces the recording track of the concave portion. While the beam spot traces the identification signal area, the light receiving unit 2
14a and 214b, summing amplifier 221 and HPF 222
The second polarity inverting circuit 61 outputs the high-frequency component of the reproduced sum signal input through to the second waveform shaping circuit 62 as it is. The second waveform shaping circuit 62 receives an input based on a reference level set so as to be able to distinguish the reproduction signal amplitudes corresponding to the above-described recess widths W _H and W _L (referred to as _SH and _SL , respectively). The obtained high-frequency signal is binarized and output to the second address reproduction circuit 63 as a digital reproduction signal. The second address reproduction circuit 63 detects a sector mark, a synchronization pattern and an address mark from the input digital reproduction signal, and recognizes that the area where the beam spot is currently traced is the identification signal area. , And decodes the track number and the address number, and outputs the decoded data to the address calculation circuit 66 as first address data together with the value of the concave / convex mark. The address calculation circuit 66 reads the value of the control signal L4 and the value of the concavo-convex mark obtained from the first address data, and confirms that both indicate a concave recording track. The data is output to the second system controller 67 as the third address data as it is. The second system controller 67, based on the input third address data,
Thereafter, control such as recording, reproduction or search is performed. If the value of the concavo-convex mark obtained from the first address data does not indicate a concave recording track, the address calculation circuit 66 discards the input first address data as an error, and inputs the next address data. Wait for it.

On the other hand, when reading the identification signal of the recording track of the convex portion, the second system controller 67 activates the first polarity inversion circuit 60 and the second polarity inversion circuit 61 through the control signal L4. The first polarity inversion circuit 60 inverts the polarity of the input tracking error signal and outputs it to the tracking control circuit 219. Thereby, the beam spot irradiated on the optical disk traces the recording track of the convex portion. While the beam spot traces the identification signal area, the second polarity inversion circuit 6
1 inverts the polarity of the high frequency component of the input reproduced sum signal and outputs the inverted signal to the second waveform shaping circuit 62. The second waveform shaping circuit 62 binarizes the input high-frequency signal based on the above-mentioned reference level, and outputs it as a digital reproduction signal to the third address reproduction circuit 65. Meanwhile, the third
The waveform shaping circuit 64 is a window comparator in which a reference level is set so as to identify a reproduction signal amplitude (this is S _O ) corresponding to the width W _O of the convex portion described above.
The amplitude of input high-frequency signal and outputs a detection pulse only when the S _O to the third address reproducing circuit 65. That is, a detection pulse is output only when a shift bit is detected. The third address reproduction circuit 65 first detects a sector mark, a synchronization pattern and an address mark from the input digital reproduction signal, and recognizes that the area currently traced by the beam spot is the identification signal area. I do. Next, based on the temporal relationship between the digital reproduction signal input from the second waveform shaping circuit 62 and the detection pulse of the shift bit input from the third waveform shaping circuit 64, the shift of the track number in the gray code is performed. Determine the position of the bit. Then, the gray code corresponding to the two binary values of the shift bits is decoded, and the smaller track number is used as the second address data together with the sector number and the value of the concave / convex mark as the second address data.
Output to The address calculation circuit 66 reads the value of the control signal L4 and the value of the concavo-convex mark obtained from the second address data, and if it is confirmed that both indicate the recording track of the convex portion, the second address data Is output to the second system controller 67 as third address data as it is. The second system controller 67 controls subsequent recording, reproduction, search, and the like based on the input third address data. If the value of the concavo-convex mark obtained from the second address data does not indicate a convex recording track, the address calculation circuit 66 discards the input first address data as an error, and inputs the next address data. Wait for it to be done.

As described above in detail, according to the optical disk apparatus of the present embodiment, while the light beam is scanning on the identification signal in the convex recording track, the polarity of the second polarity inversion circuit 61 is inverted. The second waveform shaping circuit 62 converts the reproduced signal into 2
From the digital signal obtained as a result of the binarization and the detection pulse of the shift bit of the gray code output from the third waveform shaping circuit 64, the third address reproducing circuit 65 detects the two signals recorded in the concave portions on both sides. Since a gray code is calculated and a correct track number is decoded based on the gray code, correct address data can be obtained even on a recording track having a convex portion.

FIG. 8 is a block diagram showing the configuration of the main part of the optical disk device of the second embodiment. In FIG.
Is a first polarity inversion circuit, 61 is a second polarity inversion circuit, 6
2 is a second waveform shaping circuit, 63 is a second address reproducing circuit, 66 is an address calculating circuit, 67 is a second system controller, 214a and 214b are light receiving sections of photodetectors,
217 is a differential amplifier, 218 is a low-pass filter (LP
F), 221 is an addition amplifier, 222 is a high-pass filter (HPF), 223 is a first waveform shaping circuit, 224 is a reproduction signal processing circuit, 233 is an output terminal, and the above is FIG.
Are basically the same as those of the optical disk device of the first embodiment shown in FIG.

7 will be described. The HPF 70 receives the difference signal output from the differential amplifier 217 and outputs a high-frequency signal to a fourth waveform shaping circuit 71 described later. Reference numeral 71 denotes a fourth waveform shaping circuit which receives a high-frequency signal of the difference signal from the HPF 70 and outputs a detection pulse signal to a fourth address reproducing circuit 72 described later.
Reference numeral 72 denotes a fourth address reproducing circuit which receives a digital reproduction signal from the second waveform shaping circuit 62 and a detection pulse from the fourth waveform shaping circuit 71, and outputs second address data to the address calculating circuit 66. . That is, in the present embodiment, the third embodiment of the first embodiment shown in FIG.
A fourth waveform shaping circuit 71 and a fourth address regenerating circuit 72 are provided in place of the waveform shaping circuit 64 and the third address reproducing circuit 65 of FIG. The feature is that the output of the amplifier 217 is obtained.

The operation of the optical disk device of the present embodiment configured as described above will be described with reference to the drawings focusing on the operation of the portions different from those of the first embodiment.

In this embodiment, the case of reading the identification signal of the recording track in the concave portion is the same as the case of the first embodiment.

On the other hand, when the identification signal is read from the recording track of the convex portion, the HPF 70 extracts a high-frequency component from the push-pull signal output from the differential amplifier 217 and outputs it to the fourth waveform shaping circuit 71. The fourth waveform shaping circuit 71 is a comparator having two positive and negative reference levels, and outputs the first detection pulse when the amplitude of the input push-pull signal becomes larger than the positive reference level.
, And outputs a second detection pulse when the amplitude of the push-pull signal becomes smaller than the negative reference level. From the first and second detection pulses, the fourth address reproducing circuit 72 calculates the position of the gray code shift bit in the digital signal input from the second waveform shaping circuit 62 and the binary value of the shift bit. correct. The reason why the correct binary value of the shift bit can be obtained from the high-frequency component of the push-pull signal will be described below.

FIG. 9 is a timing chart for explaining this. In FIG. 9A, the binary value of the gray code recorded in the concave portion 1 is “1010” and that of the concave portion 2 is “1110”, and the shift bit is the second bit. The width of the left side of the concave portion in the traveling direction of the beam spot is in the shift bits W _L, and that of the right side is W _H. Beam spot is convex 1
In the shift bit, the convex portion is relatively shifted with respect to the beam spot toward the concave portion 1 (L ₁ > L _{2 in} the figure), and a tracking error has occurred. It will be in the same state. Therefore, the waveform of the push-pull signal is as shown in the figure, and the fourth waveform shaping circuit 71 compares the waveform with the positive detection pulse.
Is output to the address reproduction circuit 72.

On the other hand, in FIG. 3B, the binary value of the gray code recorded in the concave portion 1 is “1010”,
Is "1000", and the shift bit is the third bit. At this time as opposed to the case of FIG. (A), the width of the left side of the concave portion in the traveling direction of the beam spot is in the shift bits W _H, right it W _L
It is. Therefore, in the shift bit, the convex portion is relatively shifted toward the concave portion 2 with respect to the beam spot. Therefore, the push-pull signal waveform is as shown in the figure,
This is compared by the fourth waveform shaping circuit 71 to output a negative detection pulse to the fourth address reproducing circuit 72.

From the above, when the binary value on the concave portion 1 side in the shift bit of the convex portion 1 is 0, a positive detection pulse is obtained, and when the binary value is 1, a negative detection pulse is obtained. The address reproducing circuit 72 can obtain the correct binary value of the shift bit in the input digital signal by referring to the polarity of the detection pulse.

As described above in detail, according to the optical disk device of the present embodiment, the differential amplifier 217 outputs the signal via the HPF 70 while the light beam scans the identification signal in the convex recording track. From the amplitude and polarity of the push-pull signal, the binary value of the gray code of the concave portion on both sides at the position of the shift bit can be determined, so that correct address data can be obtained even on the recording track of the convex portion.

[0055]

As described above in detail, in the optical disk of the present invention, the width of the recording track of the concave portion on the disk is modulated according to the identification signal, and the recording track of the adjacent concave portion has the leading end of the identification signal. Are matched, it is possible to detect the identification signal even in the recording track of the convex portion.

Further, since the gray code is used as a part of the identification signal to be recorded on the recording track of the concave portion, the reading error of the identification signal on the recording track of the convex portion is only 1 bit at most, and the value of the correct identification signal is correct. Can be easily estimated.

Further, in the optical disk apparatus of the present invention, while the light beam is scanning on the identification signal in the recording track of the convex portion, the polarity inversion means inverts the polarity of the reproduction signal from the optical head,
Since the identification signal reading means decodes the identification signal based on this, a correct identification signal can be obtained even at the convex portion.

Further, since the polarity of the reproduced signal is inverted by the polarity inverting means, the polarity becomes the same as the identification signal of the recording track in the concave portion, and the identification signal can be decoded in the concave portion and the convex portion by the same algorithm.

Further, while the light beam is scanning on the identification signal in the recording track of the convex portion, based on the amplitude and polarity of the tracking error signal output by the tracking error detecting means,
After the identification signal reading means corrects the gray code,
Since the identification signal is decoded, a correct identification signal can be obtained even at the convex portion.

[Brief description of the drawings]

FIG. 1 is an enlarged plan view of an optical disc in an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a recording format of a recording track in a concave portion of the optical disc in the embodiment.

FIG. 3 is an explanatory diagram for explaining a reason why an identification signal is obtained in a recording track of a convex portion of the optical disc in the embodiment.

FIG. 4 is a block diagram illustrating a configuration of a main part of an optical disk manufacturing apparatus according to the embodiment.

FIG. 5 is an explanatory diagram showing a trajectory of a minute beam spot at the time of manufacturing a disk in the optical disk manufacturing apparatus according to the embodiment.

FIG. 6 is an explanatory diagram showing a configuration of an acousto-optic element used in the optical disk manufacturing apparatus according to the embodiment.

FIG. 7 is a block diagram illustrating a main configuration of an optical disc device according to the first embodiment of the present invention.

FIG. 8 is a block diagram illustrating a configuration of a main part of an optical disc device according to a second embodiment of the present invention.

FIG. 9 is a timing chart for explaining the reason why a correct binary value of a shift bit can be obtained in the optical disc device of the second embodiment.

FIG. 10 is an enlarged perspective view illustrating the configuration of an optical disk used for a conventional optical disk.

FIG. 11 is a block diagram showing a configuration of a conventional optical disk device.

FIG. 12 is an enlarged perspective view for explaining a configuration of a conventional optical disc that records signals in both a concave portion and a convex portion of a recording track.

[Explanation of symbols]

 1, 3 concave portion 2 convex portion 60 first polarity inversion circuit 61 second polarity inversion circuit 62 second waveform shaping circuit 63 second address reproducing circuit 64 third waveform shaping circuit 65 third address reproducing circuit 66 Address calculating circuit 70 HPF 71 Third waveform shaping circuit 72 Fourth address reproducing circuit 210 Semiconductor laser 214 Photodetector 214a, 214b Light receiving section 215 Actuator 216 Optical head 217 Differential amplifier 219 Tracking control circuit 221 Addition amplifier 224 Reproduction signal Processing circuit 228 Spindle motor 229 Recording signal processing circuit 231 LD drive circuit

Continuation of the front page (56) References JP-A-2-68721 (JP, A) JP-A-62-278729 (JP, A) JP-A-60-121553 (JP, A) JP-A-60-247842 (JP , A) JP-A-57-50330 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 7/00-7/007 G11B 7/24 561

Claims (3)

(57) [Claims] 1. A recording track comprising both concave and convex portions formed spirally or concentrically on a disk,
Two values the width of the recess an identification signal including position information on the disc W _H and W _{L (however, W H + W L = 2P} , P is equal to the track pitch) prerecorded in a form modulated between An optical disc that records an information signal by using a change in a local optical constant or a physical shape due to irradiation of a light beam; and an optical disc that irradiates a light beam on the optical disc, receives reflected light thereof, and converts it into an electric signal. An optical head that outputs the read signal as a read signal; an identification signal reader that decodes the identification signal from the read signal; an information signal reader that decodes an information signal from the read signal output by the optical head; Information signal recording means for recording an information signal; disk rotating means for rotating the optical disk; Tracking control means for positioning on a recording track of a mark or a convex portion, wherein the identification signal matches a head position between adjacent recording tracks in at least a part of an area of the optical disk, and position information contained in the identification signal includes a gray code which changes only one bit when the count-up, the identification signal in the track of the convex portion width of the convex portion is W _H, the three values of W _L and P When reproducing the recording track of the convex portion, the identification signal reading means detects a bit in which the width of the convex portion becomes P in the gray code read signal included in the identification signal.
An optical disc device for decoding the identification signal in the recording track of the projected portion . 2. The identification signal reading means, wherein the width of the projection is P
Detection in three steps according to the width of the recess
2. The optical disk device according to claim 1 , wherein the detection is performed by detecting a reflected light amount . 3. A deviation detecting means for detecting a deviation of a light amount distribution of a light beam reflected from an optical disk in a radial direction of the disk, and outputting a deviation detection signal in accordance with the deviation. Shift bit detection means for outputting a shift bit detection signal when the deviation detection signal exceeds a predetermined positive threshold value and a predetermined negative threshold value while scanning on the identification signal in the recording track of the section 2. The optical disk device according to claim 1, wherein the shift bit detection unit detects a bit having a width of the convex portion of P.