JP2001195747A - Substrate for optical recording medium, optical recording medium, master disk, master disk recorder and signal generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of the deviation between the central position of guide grooves and the central positions of intermediate addresses within a zone of the conventional optical recording medium. SOLUTION: The optical recording medium is manufactured by utilizing the substrate for the optical recording medium which has plural recording tracks 4 formed in at least the guide grooves 1 on the disk and address parts 3 consisting of address pit strings 3a and 3b disposed between the recording tracks of the guide grooves 1 along the reading direction of information of the recording tracks 4. The recording tracks of the guide groove 1 are segmented by each of the prescribed zones (N, N+1) and are so arranged that the centers 3c of the address parts 3 corresponding to the recording tracks of the guide grooves 1 on at least the outermost periphery or innermost periphery of the respective zones are relatively shifted d1 in the radial direction of the disk with respect to the centers 1c of the recording tracks of the guide grooves 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium for recording and reproducing information by irradiating a laser beam or the like, and more particularly to a substrate, a master, a master recording apparatus and a signal generator used for the optical recording medium. is there.

[0002]

2. Description of the Related Art An optical recording medium has attracted attention as a large-capacity and high-density memory, and a rewritable type called an erasable type is currently being developed. As one of the erasable optical recording media, a recording layer composed of a thin film that changes phase between an amorphous state and a crystalline state is provided on a disk-shaped transparent substrate, and recording and erasing of information is performed by thermal energy by laser light irradiation. There is a phase change optical disk that performs the following.

A phase change optical disc is manufactured by firstly forming a phase change type recording layer on a transparent substrate provided with a guide groove having irregularities on the surface by a technique such as sputtering. 2) a bonding step of providing a protective plate on the recording layer to protect the recording thin film; and 3) an initialization process for changing the state of the recording layer from an amorphous state to a crystalline state. An initialization step to be performed. Ge, as a phase change material for the recording layer,
An alloy film containing Sb, Te, In or the like as a main component, for example, Ge
SbTe alloys are known.

Information is recorded by forming a mark by partially amorphizing the recording layer, and erasing is often performed by crystallization of the amorphous mark. Amorphization is performed by heating the recording layer to a temperature equal to or higher than the melting point and then cooling the recording layer at a speed equal to or higher than a predetermined value. On the other hand, crystallization is performed by heating the recording layer to a temperature higher than the crystallization temperature and lower than the melting point.

Address information (hereinafter abbreviated as an address) is formed on a substrate by spiral or concentric guide grooves (grooves) for tracking a laser beam during recording and reproduction and address pits composed of irregularities indicating positions on a medium. Is generally provided in advance.

[0006] Further, the address information is formed in an arrangement called ZCAV or ZCLV format. Each track is divided into several parts by an address part composed of address pits and has a plurality of recording sectors. The number of divisions of the sector in one round differs for each zone divided in the radial direction. That is, it increases sequentially in the outer peripheral direction. The number of sectors is the same in the same zone. In addition, the number of zones depends on the length of the sector,
The longer the sector, the less.

[0007] Recently, the amount of information to be handled has increased with the improvement in the processing capability of various information devices. Therefore, a recording medium capable of recording and reproducing a larger amount of information is required. As a means for increasing the capacity, DVD-R
AM and the like adopt a method of increasing the track density by using both the concave and convex portions of the guide groove as information tracks. In this case, the widths of the groove track and the land track are set to be substantially equal.

In this recording medium, a method is used in which address information is provided between a groove track and a land track, and one address portion is shared by a pair of adjacent groove tracks and land tracks. The address portion recorded between the adjacent groove track and land track is called an “intermediate address”.

FIG. 11 is a diagram showing a configuration of a substrate of an optical recording medium including an intermediate address provided in a zone.
1 is a groove track, 2 is a land track, 3 is an intermediate address, and 4 is a recording area.

The intermediate address 3 has a pair of address pits 3a, 3a at positions shifted radially by half the track pitch with respect to the track center in the radial direction.
b. Although the address pit is oval in the figure, it is replaced by a square. In another embodiment, the address portion may be not a pair of address pit rows but an address pit row that is not shifted in the radial direction. In this case, the center of the address portion is the center position of the address pit in the radial direction.

The first feature of the intermediate address 3 of this embodiment is that one address is reproduced from both the groove track 1 and the land track 2, and two addresses are provided on both sides for each track. Since it exists, high reliability can be ensured at the time of address demodulation.

The second feature is that the center position of the recording track can be accurately determined from the reproduction signals of the address pits 3a and 3b existing on the left and right. In particular,
By comparing the amplitudes of the reproduced signals from the address pits 3a and 3b and controlling the amplitudes of the reproduced signals from the two addresses to be equal, a tracking servo that follows the track center becomes possible. Due to these two features, the intermediate address 3 is used for land / groove recording.

[0013]

However, as a result of a detailed measurement of a reproduction signal obtained from a recording medium manufactured from a substrate having such a structure, the starting position (inner circumference) of each of a plurality of zones divided in the radial direction is determined. Side) and end position (outer circumference side)
, A phenomenon was found in which the relative positional relationship between the center of the guide groove and the center position of the intermediate address was shifted.

More specifically, the condition that the center position of the tracking error signal is equal to the amplitude of the reproduced signal of the intermediate address is largely changed at the boundary of the zone.

If the center position of the intermediate address is expressed by a positional shift with respect to the center position of the guide groove, a reproduced signal having a polarity generated when the entire intermediate address moves toward the inner peripheral side is obtained at the start position of the zone. At the center of the zone, the center coincides with the center of the guide groove, and at the end of the zone, a reproduced signal having a polarity generated when the intermediate address moves to the outer peripheral side is obtained.

As a result, when the tracking control for finding the center of the track using the intermediate address is performed as described above, the position deviated from the center of the guide groove at the start end position of the zone and the end position of the zone, that is, The tracking servo operates in the off-track state.

If signal recording is performed in this state, there is a problem that the quality of the signal itself deteriorates, and the signal is easily affected by crosstalk from an adjacent track, so that stable recording and reproduction becomes difficult.

The present invention solves the above-mentioned conventional problems, and provides an optical recording medium in which the center position of a guide groove generated in a zone and the center position of an intermediate address are small, and a manufacturing method and an apparatus for making them possible. The purpose is to provide.

[0019]

Means for Solving the Problems The first invention (claim 1)
Corresponds to a plurality of recording tracks formed on at least the guide grooves on the disk, and an address pit row provided between the recording tracks of the guide grooves along the information reading direction of the recording tracks. And a recording track of the guide groove is divided into predetermined zones, and of each of the zones, at least an outermost or innermost circumference of the address portion corresponding to the recording track of the guide groove. The center is a substrate for an optical recording medium, which is arranged so as to be shifted relative to the center of a recording track of the guide groove in a radial direction of the disk.

According to a second aspect of the present invention (corresponding to claim 2), the address portion comprises a pair of intermediate addresses existing at positions shifted in a radial direction of the disk, and the center of the address portion is The optical recording medium substrate according to claim 1, wherein the substrate is a center line between central axes of the intermediate addresses.

According to a third aspect of the present invention (corresponding to claim 3), the direction of the shift of the center of the address portion is the shift corresponding to the outermost recording track in the same zone and the innermost recording. 2. The optical recording medium substrate according to claim 1, wherein the shifts corresponding to the tracks are opposite to each other.

According to a fourth aspect of the present invention (corresponding to claim 4), the amount of shift of the center of the address portion is continuous or in each of the zones from the outermost or innermost periphery to the central portion. 4. The substrate for an optical recording medium according to claim 3, wherein the substrate is decreased stepwise.

According to a fifth aspect of the present invention (corresponding to claim 5), there is provided an optical recording medium substrate used for producing an optical recording medium by a predetermined manufacturing method, wherein a shift amount and a direction of the center of the address portion are provided. An optical recording medium is created by the manufacturing method using a calibration substrate in which the amount of shift of the center of the address portion is zero, and the address portion appearing in a reproduced signal when the optical recording medium is reproduced. 2. The optical recording medium substrate according to claim 1, wherein the amount and direction of the shift of the center are amounts and directions that cancel each other.

A sixth aspect of the present invention (corresponding to claim 6) is characterized in that a phase change type recording thin film layer is provided on the upper surface of the optical recording medium substrate according to any one of claims 1 to 4. Optical recording medium.

According to a seventh aspect of the present invention (corresponding to claim 7), the optical recording medium according to claim 6, wherein the phase change type recording thin film layer has been initialized.

According to an eighth aspect of the present invention (corresponding to claim 8), there is provided a master for producing the optical recording medium substrate according to claim 1, wherein a portion corresponding to the guide groove and the address portion is formed by: This is a master for producing an optical recording medium substrate, which is formed on a glass master having a photoresist layer.

According to a ninth aspect (corresponding to claim 9), there is provided an original recording apparatus for producing an original for producing the optical recording medium substrate according to claim 8, wherein the photoresist of the glass original is used. A light source for exposing the layer, a light modulator for modulating the light of the light source in accordance with an address signal, and a deflector for deflecting the light-modulated light. A parallel or meandering guide groove, and (b) shifting the light beam in the radial direction of the master for the address section so that at least the outermost or innermost of each zone. The optical modulation is performed such that the center of the address portion corresponding to the recording track of the guide groove in the periphery is relatively shifted in the radial direction of the disk with respect to the center of the recording track of the guide groove. And a master recording apparatus and a EO deflector for deflecting the light.

A tenth aspect of the present invention (corresponding to claim 10) is:
A master recording apparatus for recording information on a master for producing the substrate for an optical recording medium according to claim 8, wherein a light source for exposing a photoresist layer of the glass master and light from the light source are addressed. A light modulator that modulates according to a signal, and deflects the light-modulated light beam in synchronization with the timing of the address signal so that the center of the address portion coincides with the center of the recording track of the guide groove. A first light beam output for forming the address portion;
EO deflector and the light output from the first EO deflector, and (a) for the recording track section,
In order to form the guide grooves meandering along the direction of the address pit row, and (b) at least the outermost or innermost guide grooves of each zone for the address section. The light beam is deflected in the radial direction of the master so that the center of the address portion corresponding to the recording track is relatively shifted in the radial direction of the disk with respect to the center of the recording track in the guide groove. And a second optical deflector.

[0029] The eleventh invention (corresponding to claim 11) provides:
The direction of light deflection in the address portion by the second EO deflector is different between a deflection corresponding to the outermost recording track and a deflection corresponding to the innermost recording track in the same zone. The master recording apparatus according to claim 10, wherein the master recording apparatus is in a reverse direction.

The twelfth invention (corresponding to claim 12) provides:
The amount of deflection of the address section by the second EO deflector is reduced continuously or stepwise from the outermost or innermost circumference toward the center of each zone. 12. The master recording apparatus according to item 11.

According to a thirteenth aspect of the present invention (corresponding to claim 13),
A master recording apparatus for recording information on a master for producing an optical recording medium substrate used for producing an optical recording medium by a predetermined manufacturing method, wherein the light beam is deflected by the second EO deflector. The direction and the amount of deflection are determined by using the calibration substrate in which the amount of shift of the center of the address portion is zero, creating an optical recording medium by the above-described manufacturing method, and reading the address appearing in a reproduced signal when reproducing the same. 13. The master recording apparatus according to claim 9, wherein the deflection direction and the deflection amount can cancel the shift amount and the direction of the center of the unit.

The fourteenth invention (corresponding to claim 14) provides:
The said E used in the master recording apparatus according to claim 9.
A signal generator for generating a signal for driving an O deflector, comprising: outputting a binary signal corresponding to the address signal to the optical modulator; And (b) shifting the light beam in the radial direction of the master for the address section so that The center of the address portion corresponding to the recording track of at least the outermost or innermost guide groove is shifted relative to the center of the recording track of the guide groove in the radial direction of the disk. This is a signal generator that outputs a shift voltage for deflecting the light modulated light.

According to a fifteenth aspect of the present invention (corresponding to claim 15),
A signal generator for generating a signal for driving the first EO deflector and the second deflector, which is used in the master recording apparatus according to claim 10, wherein the address is transmitted to the optical modulator. Outputting a binary signal corresponding to the first signal;
The EO deflector deflects the light-modulated light beam in synchronization with the timing of the address signal, and applies a voltage that causes the center of the address portion to coincide with the center of the recording track of the guide groove. And outputs the second EO
In the deflector, (a) for the recording track section, the guide groove meandering along the direction of the address pit row is formed, and (b) for the address section, The center of the address portion corresponding to the recording track of at least the outermost or innermost guide groove of each zone is shifted relative to the center of the recording track of the guide groove in the radial direction of the disk. A signal generator for outputting an offset voltage for deflecting the light beam in a radial direction of the master.

According to a sixteenth aspect of the present invention (corresponding to claim 16),
The shift voltage to the EO deflector or the second EO deflector has opposite polarities in a voltage corresponding to the outermost recording track and a voltage corresponding to the innermost recording track in the same zone. 2. The method according to claim 1, wherein
A signal generator according to 4 or 15.

The seventeenth invention (corresponding to claim 17) is:
The shift voltage to the EO deflector or the second EO deflector is reduced continuously or stepwise in each of the zones from the outermost or innermost circumference toward the center. A signal generator according to 14 or 15.

The eighteenth invention (corresponding to claim 18) is:
A signal generator used in a master recording device for recording information on a master for producing an optical recording medium substrate used for producing an optical recording medium by a predetermined manufacturing method, wherein the EO deflector or the second EO deflector is used. The polarity and the magnitude of the shift voltage to the EO deflector are determined by using the calibration substrate in which the amount of shift of the address portion is zero, using the above-described manufacturing method to create an optical recording medium, and reproducing the optical recording medium. 15. A polarity and a magnitude which cancel out a shift amount and a direction of the address portion appearing in a reproduction signal.
Or a signal generator according to 15.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a substrate, an optical recording medium and a recording / reproducing apparatus according to the present invention will be described with reference to the drawings.

As described above, the misalignment between the center of the guide groove and the center of the address portion at the zone boundary is not remarkable in the substrate alone, but occurs in the subsequent steps after the formation of the recording layer. it is conceivable that.

Therefore, the present invention measures the amount of displacement between the address portion and the guide groove in the radial direction in an optical recording medium completed through each process using a calibration substrate prepared by a conventional method. Next, based on the amount of displacement at each radial position obtained as a result of the measurement, an address portion shifted in the direction opposite to the direction of the above-described displacement at the stage of the substrate is formed in advance, so that the final light An object of the present invention is to obtain an address portion and a guide groove which are not misaligned in the form of a recording medium.

The optical recording medium to which the present invention is applied has a circular shape, and has a guide groove for tracking when recording an information signal on the surface thereof, and a part of the guide groove is interrupted to provide an address pit. At this time, the address pits are arranged by using a ZCAV (zone constant angular velocity) method, dividing into a plurality of sectors in the circumferential direction, further dividing into zones in the radial direction, and increasing the number of sectors toward the outer periphery. Configuration.

FIG. 1 is a diagram showing the configuration of a guide groove and an address portion at a zone boundary of a substrate for an optical recording medium according to the present invention. In the figure, each of the concaves and convexes of the guide groove is a recording track for forming the recording area 4 and includes a groove track 1 and a land track 2.

The address section provides an intermediate address 3 at a position shifted left and right with respect to the center position of each recording track. At this time, the position of the intermediate address is provided at a position shifted from the center 1c of the groove track or the center 2c of the land track by approximately 1/2 track pitch.
Here, the intermediate address is composed of a first address pit 3a located ahead of the light beam and a second address pit row 3b located behind. The center line 3c of the center 3ac, 3bc of each address pit is defined as the center line of the intermediate address. Note that the center line of the intermediate address is the first track on the outer peripheral side with respect to the groove track 1.
And the center line of the second address pit on the inner circumference side, and is located between the first address pit on the inner circumference side and the second address pit on the outer circumference side with respect to the land track.

In the present invention, the relative positional relationship between the track center of the guide groove and the center line of the intermediate address is set to different values in the radial direction in each zone.

FIG. 1 shows the sector arrangement at the boundary position between zone (N) and zone (N + 1), and shows the end position of zone (N) and the start position of zone (N + 1). Here, the shift amount of the center line of the intermediate address from the center line of the guide groove is defined as d. At the start position of the zone, that is, in the zone (N + 1) in the figure, the center line 3c of the intermediate address is arranged so as to be shifted to the outer peripheral side by the shift amount d1 with respect to the track center 1c of the guide groove. At the end position of the zone, that is, in the area of zone (N) in the drawing, the center line of the intermediate address is shifted to the inner peripheral side by d2 with respect to the center of the guide groove.

FIG. 2 is a diagram showing the positional deviation d of the center line of the intermediate address with respect to the center of the guide groove in the radial direction of the recording medium. At the start position of the zone, the shift amount is shifted to the outer peripheral side (+ direction) by d1. The shift amount decreases toward the center of the zone, becomes 0 at the center position, and shifts toward the inner peripheral side (− direction) as the zone ends. At the end, the shift amount is set to d2.

The center position of the guide groove and the value of the shift amount d of the intermediate address are set in advance to the shift amount d which is a feature of the present invention.
Using a calibration substrate manufactured by the conventional method
An optical recording medium is prepared by a series of predetermined manufacturing processes including film formation, bonding, initialization, and the like of a recording material layer.

In each zone of the created optical recording medium,
The amount of deviation between the center of the guide groove and the center line of the intermediate address is measured. The shift amount is shifted in the opposite direction by the same amount as the shift amount, and a substrate corresponding to FIG. 2 is formed by the same process as the predetermined manufacturing process.

Note that the deviation amount between the center of the guide groove and the center line of the intermediate address shown here is the difference between the position that is the center position of the amplitude of the tracking error signal and the position where the reproduction amplitudes of the pair of intermediate addresses match. This is a value obtained from the difference.

With the above structure, the deviation between the center position of the guide groove and the center line of the intermediate address caused in the manufacturing process of the optical recording medium is corrected, and the center of the guide groove in the optical recording medium completed in the final form is corrected. It is possible to make the center position of the line coincide with the center position of the intermediate address. As a result, off-track at the time of control that occurs when the recording medium tilts in the radial direction is compensated by the track center servo using the intermediate address, and stable recording and reproduction can be performed.

Next, a master recording apparatus for producing a master for obtaining a substrate for an optical recording medium according to the present invention will be described with reference to the block diagram of FIG. In FIG. 1, the guide grooves in the recording area (section) are shown in the form of non-modulated parallel guide grooves. However, in the embodiments of FIGS. The guide groove is a wobble groove meandering.

A glass master 21 having a surface coated with a photoresist layer is rotated by a spindle motor 22. The light beam emitted from the recording light source 23 that exposes the photo resist layer is reflected by the mirror 24 and
The light enters the O modulator (electric / optical element) 25. The EO modulator modulates the intensity of the incident light beam according to a modulation signal corresponding to the address signal from the format control unit 26 that controls the entire mastering apparatus.

Next, the light beam emitted from the EO modulator 25 and reflected by the second mirror 27 is used to shift the intermediate address from the format control unit 26 by a half track pitch in the track direction. The light beam is deflected by the first EO deflector 28 in accordance with the control voltage of The first EO deflector 28 operates in the address section, but does not deflect in the recording area. E of the present invention
The O deflector corresponds to the first EO deflector.

Next, the second EO deflector 29 deflects the light beam according to a wobble voltage for meandering the guide groove from the format controller 26 at a predetermined frequency.

The light beam from the second EO deflector 29 is
The light is reflected by the third mirror 30, condensed into a minute spot by the objective lens 31, and irradiates the photoresist layer on the surface of the glass master 21.

Although not shown in detail in the drawing, the present recording system includes a focus control system using an auxiliary beam for keeping the distance between the objective lens 31 and the glass master 21 constant.

FIG. 4 is a diagram showing details of the format control unit 26 that generates a control signal for controlling the light beam of the master recording apparatus. Hereinafter, the operation of the format control unit 26 will be described with reference to FIG. Recording is started in accordance with a recording start signal from an external controller. First, at a timing synchronized with a signal indicating a rotational position from the spindle motor 23, an address signal converted into a code signal is generated from the address generation circuit 41, and the address modulation is performed. The modulated signal is output to the EO modulator 25 via the modulator 42.

The offset voltage generation circuit 45 determines the position in the zone from the output of the track count circuit 44 for measuring the number of tracks in the zone of the address signal of the address generation circuit 41, and generates an offset voltage according to the result. , To the address deflector 43.

The address deflecting circuit 43 responds to the timing signal synchronized with the address modulation signal output from the address signal generator 41 by using the first address pit string and the second address pit string.
In synchronization with the timing of the corresponding modulation signal, generates a first deflection signal for shifting the address pit row by the same distance to the left and right with respect to the center of the guide groove, and further generates the first deflection signal and an offset voltage circuit 45. Is output to the first EO deflector 28.

FIG. 5 shows the dependence of the output voltage of the offset voltage circuit 45 on the radial position. At the beginning of the zone where the zone (N) starts, a positive offset voltage Vf1 is generated,
Decrease the offset voltage toward the center of the zone,
Zero at the center of the zone. Further, a negative offset voltage is applied to the end of the zone, and a negative offset voltage of Vf2 is generated at the end of the zone.

Here, the method of continuously changing the offset voltage with respect to the zone position has been described.
The offset voltage may be changed stepwise in units of a plurality of tracks, for example, 20 tracks. In this case, the offset voltage generation circuit can be simplified.

For a different zone, the center position deviation of the intermediate address is measured based on a value obtained by measuring the center position shift amount of the intermediate address using a disk prototyped by a conventional method in which the condition of the intermediate address is not changed between the zones in advance. It is preferable to set an offset voltage.

However, the offset voltage generation circuit 4
From the viewpoint of simplifying the circuit of FIG. 5, when the variation of the shift amount among the plurality of divided zones is small, as shown in FIG. In the zone (N + 1) on the outer peripheral side, for example, V
f1, zero at the center, Vf2 at the end of the zone
By setting the offset voltage, the offset voltage generation circuit can be simplified.

FIG. 6 is a diagram showing the output waveform of the deflection signal from the address deflection circuit 43 in the address area.
FIG. 6B shows the address deflection voltage at the center of the zone. Since the output from the offset voltage circuit 45 is zero, the voltage that shifts the guide groove by the same distance to the left and right by 1/2 track pitch is applied. A positive deflection voltage Va is generated for the first address pit row ahead, and a deflection voltage Vb having the same value as Va and a negative polarity is output for the subsequent second address pit row. I do.

FIG. 6A shows a zone start end, in which an offset voltage Vf1 is inputted from an offset voltage circuit.
The address deflection circuit 43 outputs a voltage (Va + Vf1) for the first address pit, and outputs a voltage (Vb + Vf1) for the second address pit.

On the other hand, FIG. 6C shows a zone end portion.
The offset voltage Vf2 is input from the offset voltage circuit, and the address deflection circuit 43 outputs a voltage (Va + Vf2) for the first address pit and outputs a voltage (Vb + Vf2) for the second address pit. In addition,
When the deflection voltage is positive, the light beam moves in the outer peripheral direction with respect to the glass master. As a result, at the beginning of the zone, the center position of the intermediate address is shifted toward the outer periphery, and at the end of the zone, the center address is formed at a position shifted toward the inner periphery.

Next, a second method of correcting the shift amount of the intermediate address according to the zone position will be described. The second method is a case where the guide groove is wobbled in the recording area, and the degree of deflection of the wobble is substantially equal to the degree of deflection of the offset. In comparison, the pair of address pit strings are generated. Focusing on the fact that the degree of deflection is large, the first deflector is used for the address pit row, and the second deflector connected in series after the first deflector is used for the wobble and the offset. Things. This makes it possible to use a low-cost deflector.

The format control section 26 shown in FIG. 7 applies an offset to the second EO deflector used for modulating the groove wobble when the guide groove has a wobble form, thereby providing an intermediate address. It is intended to correct the displacement.

The address deflecting circuit 71 shifts the first address pit row and the second address pit row by the same distance to the right and left with respect to the center of the guide groove in accordance with the timing synchronized with the address modulation signal generated from the address signal generator. , The signals having the same voltage difference and different polarities are output to the first EO deflector 28.

The offset voltage generation circuit 73 determines the position in the zone by counting the number of tracks in each zone by the track count circuit 44 for measuring the number of tracks of the address signal of the address generation circuit 41 in the zone, The offset voltage is generated according to the result,
Output to the groove wobble circuit 72.

The groove wobble circuit 72 generates a wobble voltage for meandering the guide groove left and right at a timing corresponding to the guide groove.

Further, the groove wobble circuit 72 outputs the output voltage of the offset voltage generation circuit 73 to the second EO deflector 29 at the timing corresponding to the intermediate address area.

FIG. 8 is a diagram showing the radial position dependence of the output voltage of the offset voltage generation circuit 73. At the start point of the zone, a positive offset voltage Vf3 is generated, and the offset voltage is decreased toward the center of the zone. Further, a negative offset voltage is applied to the end of the zone, and a negative offset voltage of Vf4 is generated at the end of the zone.

FIG. 9 is a diagram showing an output waveform of the deflection signal from the groove wobble circuit 72 in the vicinity of the address area. FIG. 9B shows the address deflection voltage at the center of the zone. A wobble voltage Vw corresponding to the wobble amount of the guide groove is output in a region corresponding to the guide groove. Is zero, the voltage goes to zero level.

FIG. 9A shows the beginning of the zone, in which an offset voltage Vf3 is input from an offset voltage circuit.
The intermediate address area outputs a voltage (Vf3). on the other hand,
FIG. 9 (c) shows a zone end portion, in which an offset voltage Vf4 is input from an offset voltage circuit, and the groove wobble circuit 72 outputs a voltage (Vf4) in an intermediate address area. When the deflection voltage is positive, the light beam moves in the outer peripheral direction with respect to the glass master. As a result, at the beginning of the zone, the center position of the intermediate address shifts toward the outer periphery,
At the end of the zone, it is formed at a position shifted inward.

FIG. 10 is a view showing an example of a substrate on which an intermediate address according to the present invention is formed using the circuit shown in FIG. 7 by using a wobble guide groove. The difference from FIG. 1 is that the groove track 91 and the land track 92, which are recording tracks, meander, but the track center is the average center line.

By applying the correction according to the present invention, the center of the intermediate address is shifted in the outer peripheral direction by d91 at the start end of the zone, and shifted to the inner peripheral side by d92 at the end of the zone.

With the above configuration, by applying an offset voltage to the second deflector for wobbling the guide groove, the guide groove and the intermediate address position in the zone can be corrected. .

Although the method of continuously changing the offset voltage with respect to the zone position has been described, a method of changing the offset voltage stepwise in units of a plurality of tracks, for example, 20 tracks may be used. In this case, the offset voltage generation circuit can be simplified.

For the different zones, the center position deviation of the intermediate address is measured based on the value obtained by measuring the center position shift amount of the intermediate address using a board prototyped in advance by a conventional method in which the condition of the intermediate address is not changed between the zones. It is preferable to set the offset voltage appropriately.

However, the offset voltage generation circuit 4
From the viewpoint of simplifying the circuit of FIG. 5, when the difference in the shift amount between the zones is small, the shift amount in each zone is set to a constant value as shown in FIG. In (N + 1), similarly to the zone (N), the offset voltage generation circuit can be simplified by setting the offset voltage to Vf1 at the start of the zone, zero at the center, and Vf2 at the end of the zone.

Next, a process of manufacturing a mold (stamper) for forming a substrate by using the master recording apparatus of FIG. 3 will be described.

The master recording device is controlled by the two types of format controllers described above, and the glass master having a photoresist on its surface is exposed. Next, after removing the exposed portion by an etching step, a conductive layer is deposited on the surface.
Further, a metal layer such as Ni is formed on the surface by electroforming, and the metal layer is peeled off to obtain a mold.

Next, this mold is mounted on an injection molding machine, and a resin material such as polycarbonate or PMMA is injected and peeled from the mold to obtain a resin substrate having a guide groove and an intermediate address on the surface. Can be.

A recording material layer is formed on the surface of the obtained substrate by a thin film process such as sputtering or vapor deposition, and then a protective cover is provided. Next, when the recording material layer is of a phase change type in the initialization step, light irradiation for crystallization is performed. Through the above steps, a recordable phase change recording medium can be obtained.

As a specific example, a ZnS-SiO2 dielectric as a recording layer is formed on a substrate made of polycarbonate resin having a thickness of 0.6 mm and provided with a guide groove having a track pitch of 0.6 μm and an intermediate address according to the present invention. Body layer, G
An eSbTe phase-change recording thin film layer, a ZnS-SiO2 dielectric layer, and an Al alloy reflection layer are sequentially formed by a sputtering method. A phase-change optical recording medium can be obtained by bonding a protective cover made of a polycarbonate resin having a thickness of 0.6 mm on the Al alloy reflective layer using an ultraviolet curable resin layer.

The recording thin film layer is irradiated with high-power laser light on a stripe of 100 μm length while rotating the recording medium, thereby performing an initialization process of changing the amorphous state from the sputtered state to the crystalline state. Thus, a phase-change optical recording medium is obtained.

In the initialization step when the recording material layer is a magneto-optical recording material, a process is performed in which a magnetic field is applied to irradiate light to make the magnetization direction constant.

As a result of performing these processes, the optical recording medium obtained through the above-described series of manufacturing steps using the substrate shown in FIG. 1 or FIG. Coincide with each other. As a result, by applying the tracking servo in which the light beam follows the center position of the intermediate address, stable tracking servo can be performed even when the substrate or the optical head is tilted.

Although the description has been made with reference to the intermediate address provided between the land track and the groove track, the present invention is directed to a recording medium having a guide groove and address pits, and having a different number of sectors in each zone. It is possible to adapt to. For example, the center position can be corrected in the same manner for a recording medium having a format in which the center of the address pit and the center of the guide track are aligned.

[0090]

As described above, according to the present invention, the guide groove of the completed optical recording medium and the center position of the intermediate address can be matched, and the zone boundary area of the track center servo using the intermediate address can be used. Can be eliminated and stable tracking servo can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a configuration of an embodiment of a substrate for an optical recording medium of the present invention.

FIG. 2 is a diagram showing the zone position dependence of the amount of displacement of an intermediate address according to the present invention.

FIG. 3 is a block diagram illustrating a configuration of a master recording apparatus according to the present invention.

FIG. 4 is a block diagram showing a configuration of a format control unit according to the present invention.

FIG. 5 is a diagram showing the zone position dependence of the offset voltage of the EO deflector of the present invention.

FIG. 6 is a diagram showing the zone position dependence of the deflection voltage of the EO deflector of the present invention.

FIG. 7 is a block diagram showing a configuration of a second format control unit according to the present invention.

FIG. 8 is a diagram showing the zone position dependence of the offset voltage of the second offset voltage generation circuit of the present invention.

FIG. 9 is a diagram showing the zone position dependence of the wobble voltage from the groove wobble circuit of the present invention.

FIG. 10 is a schematic diagram showing the configuration of a substrate in the form of a groove wobble of an optical recording medium.

FIG. 11 is a diagram showing a configuration of a substrate of an optical recording medium.

[Explanation of symbols]

 Reference Signs List 1 groove track 1c track center 2 land track 3 intermediate address 3c intermediate address center 4 recording area 21 master 23 light source 24, 27, 30 mirror 25 EO modulator 26 format controller 28 first EO deflector 29 second EO deflector 45 offset voltage Generation circuit d1, d2 shift

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tetsuya Akiyama 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. (Reference) 5D029 WA28 WD12 WD16 5D044 BC02 CC06 DE03 DE17 DE52 DE57 5D090 AA01 BB01 CC01 DD03 EE02 FF02 FF07 FF13 FF14 FF22 GG05 GG09 KK09 5D121 BB01 BB21 BB26 BB38

Claims (18)

[Claims] 1. A disk comprising: a plurality of recording tracks formed on at least guide grooves on a disk; and address pit rows provided between recording tracks of the guide grooves along an information reading direction of the recording tracks. And a recording track of the guide groove is divided for each predetermined zone, and of each of the zones, the recording track of the address section corresponding to at least the outermost or innermost recording track of the guide groove. The substrate for an optical recording medium, wherein a center is arranged so as to be shifted in a radial direction of the disc relative to a center of a recording track of the guide groove. 2. The address section comprises a pair of intermediate addresses existing at positions shifted in a radial direction of the disk, and the center of the address section is a center line between central axes of the intermediate addresses. The substrate for an optical recording medium according to claim 1, wherein: 3. The shift direction of the center of the address portion is opposite to the shift corresponding to the outermost recording track and the shift corresponding to the innermost recording track in the same zone. The substrate for an optical recording medium according to claim 1, wherein: 4. The amount of shift of the center of the address portion is:
4. The optical recording medium substrate according to claim 3, wherein in each of the zones, the density decreases continuously or stepwise from the outermost circumference or the innermost circumference toward the center. 5. An optical recording medium substrate used for producing an optical recording medium by a predetermined manufacturing method, wherein the shift amount and the direction of the center of the address portion are the shift amount of the center of the address portion. An optical recording medium is prepared by the above-described manufacturing method using a calibration substrate having zero, and the shift amount and direction of the center of the address portion appearing in a reproduced signal when reproducing the optical recording medium are offset. 2. The substrate for an optical recording medium according to claim 1, wherein the substrate has an amount and a direction. 6. An optical recording medium comprising a phase-change recording thin film layer on the upper surface of the optical recording medium substrate according to claim 1. 7. The optical recording medium according to claim 6, wherein the phase-change recording thin-film layer has been initialized. 8. A master for producing the substrate for an optical recording medium according to claim 1, wherein a portion corresponding to the guide groove and the address portion is:
A master for producing an optical recording medium substrate, which is formed on a glass master having a photoresist layer. 9. A master recording apparatus for producing a master for producing the optical recording medium substrate according to claim 8, wherein: a light source for sensitizing a photoresist layer of the glass master; A light modulator for modulating light from a light source according to an address signal; and a deflector for deflecting the light-modulated light. (A) forming a guide groove parallel or meandering with respect to the recording track section; (B) for the address section, the light beam is shifted in the radial direction of the master to correspond to the recording track of at least the outermost or innermost guide groove of each zone. EO deflection for deflecting the light-modulated light so that the center of the address portion shifts relatively to the center of the recording track of the guide groove in the radial direction of the disk. Master recording apparatus comprising and. 10. A master disc recording apparatus for recording information on a master disc for producing the optical recording medium substrate according to claim 8, wherein: a light source for exposing a photoresist layer of the glass master disc to light; An optical modulator that modulates light from a light source in accordance with an address signal, and deflects the light-modulated light beam in synchronization with the timing of the address signal, so that the center of the address portion is at the center of the recording track of the guide groove. On the other hand, a first E for outputting a light beam for forming the address portion in a coincident state
An O deflector, and light output from the first EO deflector,
(A) The guide groove meandering along the direction of the address pit row is formed for the recording track section, and (b) the zone of each zone is formed for the address section. The center of the address portion corresponding to the recording track of at least the outermost or innermost guide groove is shifted relative to the center of the recording track of the guide groove in the radial direction of the disk. A second optical deflector for deflecting the light beam in a radial direction of the master to offset the light beam; 11. The direction of deflection of light in the address section by the second EO deflector corresponds to the deflection corresponding to the outermost recording track and the innermost recording track in the same zone. 11. The master recording apparatus according to claim 10, wherein the directions of the original recording and the deflection are opposite to each other. 12. The method according to claim 12, wherein the amount of deflection in the address portion by the second EO deflector is reduced continuously or stepwise in each of the zones from the outermost or innermost circumference toward the center. Claim 11
Master recording apparatus according to item 1. 13. An original recording apparatus for recording information on an original for producing an optical recording medium substrate used for producing an optical recording medium by a predetermined manufacturing method, wherein the information is recorded by the second EO deflector. The direction of deflection and the amount of deflection of the light beam are: a read signal when an optical recording medium is created by the manufacturing method using a calibration substrate in which the amount of shift of the center of the address portion is zero, and this is read. The master recording apparatus according to claim 9, wherein the deflection direction and the deflection amount are such that the shift amount and the direction of the center of the address portion appearing therein can be offset. 14. A signal generator for generating a signal for driving the EO deflector used in the master recording apparatus according to claim 9, wherein a signal corresponding to the address signal is supplied to the optical modulator. A value signal is output to the EO deflector, (a) a voltage for forming a parallel or meandering guide groove for the recording track section, and (b) a voltage for forming the address section. By shifting the light beam in the radial direction of the master,
The center of the address portion corresponding to the recording track of at least the outermost or innermost guide groove of each zone is shifted relative to the center of the recording track of the guide groove in the radial direction of the disk. A signal generator for outputting a shift voltage for deflecting the light-modulated light. 15. A signal generator for generating a signal for driving the first EO deflector and the second deflector, used in the master recording apparatus according to claim 10, wherein the optical modulation A binary signal corresponding to the address signal, and deflects the light-modulated light beam to the first EO deflector in synchronization with the timing of the address signal.
A voltage is output so that the center of the address portion coincides with the center of the recording track of the guide groove. To the second EO deflector, (a) for the recording track section, the address pit In order to form the guide grooves meandering along the row direction, and (b) for the address section, at least the outermost or innermost recording tracks of the guide grooves in each zone. An offset voltage for deflecting the light beam in the radial direction of the master is output such that the center of the corresponding address portion is relatively shifted in the radial direction of the disk with respect to the center of the recording track of the guide groove. Signal generator. 16. The shift voltage applied to the EO deflector or the second EO deflector includes a voltage corresponding to the outermost recording track and a voltage corresponding to the innermost recording track in the same zone. 16. The signal generator according to claim 14, wherein the signal generators have opposite polarities. 17. The shift voltage to the EO deflector or the second EO deflector is reduced in each zone continuously or stepwise from the outermost or innermost circumference toward the center. 14. The method according to claim 14, wherein
The signal generator according to claim 1. 18. A signal generator used in a master recording apparatus for recording information on a master for producing an optical recording medium substrate used for producing an optical recording medium by a predetermined manufacturing method, wherein the EO The polarity and magnitude of the shift voltage to the deflector or the second EO deflector are determined by preparing an optical recording medium by the manufacturing method using a calibration substrate in which the shift amount of the address portion is zero. The signal generator according to claim 14 or 15, wherein the polarity and the magnitude cancel out the amount and direction of the shift of the address portion appearing in the reproduced signal when the data is reproduced.