JP4350296B2 - Substrate for optical recording medium, optical recording medium, master, master recording device, and signal generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical recording medium that records and reproduces information by irradiation with a laser beam or the like, and further relates to a substrate of the optical recording medium, a master, a master recording device, and a signal generator used therefor.
[0002]
[Prior art]
As a large-capacity and high-density memory, an optical recording medium is attracting attention, and a so-called erasable type that can be rewritten is being developed. As one of the erasable optical recording media, a recording layer consisting of a thin film that changes between an amorphous state and a crystalline state is provided on a disc-shaped transparent substrate, and information is recorded and erased by thermal energy generated by laser light irradiation. There are phase change optical discs that perform.
[0003]
As the manufacturing process of the phase change optical disk, first, a film forming process in which a phase change type recording layer is formed on a transparent substrate having a guide groove having irregularities on its surface by a technique such as sputtering, and second, recording. A laminating step for providing a protective plate for protecting the thin film to protect the thin film. Third, initialization for performing an initialization process for changing the state of the recording layer from the amorphous state to the crystalline state. It consists of a process. As a phase change material for the recording layer, an alloy film mainly composed of Ge, Sb, Te, In or the like, for example, a GeSbTe alloy is known.
[0004]
Information recording is often performed 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 the melting point or higher and then cooling it at a speed equal to or higher than a certain value. On the other hand, crystallization is performed by heating the recording layer to a temperature not lower than the crystallization temperature and not higher than the melting point.
[0005]
Address information (hereinafter also abbreviated as “address”) composed of spiral or concentric guide grooves (grooves) for tracking laser light during recording and reproduction and address pits comprising irregularities indicating the position on the medium is previously recorded on the substrate. Generally it is provided.
[0006]
Further, the address information is formed in an arrangement called a ZCAV or ZCLV format, and each track is divided into several by an address portion made up of address pits and has a plurality of recording sectors. The number of divisions of the sector of one round differs for each zone divided in the radial direction. That is, it increases sequentially in the outer peripheral direction. In the same zone, the number of sectors is the same. Furthermore, the number of zones depends on the length of the sector and decreases with the length of the sector.
[0007]
Recently, the amount of information to be handled has increased with the improvement of the processing capability of various information devices. Therefore, a recording medium capable of recording / reproducing a larger amount of information is required. As a means for increasing the capacity, a DVD-RAM or the like employs 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 approximately equal.
[0008]
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 with a pair of adjacent groove tracks and land tracks. The address portion recorded in the middle between the adjacent groove track and land track is called “intermediate address”.
[0009]
FIG. 11 is a diagram showing the configuration of the substrate of the optical recording medium including the intermediate address provided in the zone. 1 is a groove track, 2 is a land track, 3 is an intermediate address, and 4 is a recording area.
[0010]
The intermediate address 3 is composed of a pair of address pits 3a and 3b at positions shifted in the radial direction by ½ of the track pitch in the radial direction with respect to the track center. In the figure, the address pits are oval, but squares are substituted. In another embodiment, the address portion may be an address pit string that is not shifted in the radial direction, instead of such a pair of address pit strings. In this case, the center of the address portion is the center position in the radial direction of the address pit.
[0011]
The first feature of the intermediate address 3 of the present embodiment is a configuration in which one address is reproduced from both the groove track 1 and the land track 2, and there are two addresses on both sides for each track. In other words, it is possible to ensure high reliability during address demodulation.
[0012]
The second feature is that the center position of the recording track can be accurately obtained from the reproduction signals of the address pits 3a and 3b existing on the left and right. Specifically, 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, tracking servo that follows the track center can be performed. Become. Due to these two characteristics, intermediate address 3 is used for land / groove recording.
[0013]
[Problems to be solved by the invention]
However, as a result of detailed measurement of the reproduction signal obtained from the recording medium produced from the substrate having such a structure, the start position (inner circumference side) and the end position (outer circumference side) of each zone divided into a plurality of portions in the radial direction. In FIG. 5, a phenomenon was observed in which the relative positional relationship between the center of the guide groove and the center position of the intermediate address was shifted.
[0014]
Specifically, this is a phenomenon that the condition where the center position of the tracking error signal is equal to the amplitude of the reproduction signal of the intermediate address varies greatly at the zone boundary.
[0015]
If the center position of the intermediate address is expressed as a positional deviation with respect to the center position of the guide groove, a reproduction signal having a polarity generated when the entire intermediate address moves to the inner peripheral side is obtained at the start position of the zone, and the center of the zone is obtained. In the portion, a reproduction signal having a polarity coincident with the center of the guide groove and generated when the intermediate address moves to the outer peripheral side at the end position of the zone is obtained.
[0016]
As a result, when the tracking control for obtaining the center of the track using the intermediate address as described above is performed, the track is off-tracked at a position shifted from the center of the guide groove at the start position of the zone and the end position of the zone. The tracking servo operates in the state.
[0017]
When signal recording is performed in this state, there is a problem that the quality of the signal itself is deteriorated and it is easily affected by crosstalk from adjacent tracks, which makes it difficult to perform stable recording and reproduction.
[0018]
The present invention solves the above-described conventional problems, and provides an optical recording medium in which the shift between the center position of the guide groove generated in the zone and the center position of the intermediate address is small, and a manufacturing method and apparatus enabling the same. With the goal.
[0019]
[Means for Solving the Problems]
  1st this inventionIsA plurality of recording tracks formed on at least the guide groove on the disc; and
  An address portion formed of an address pit row provided between the recording tracks of the guide groove along the information reading direction of the recording track;
  The recording track of the guide groove is divided into predetermined zones,
  The center of the address portion corresponding to the recording track of at least the outermost or innermost guide groove of each zone is:
  The guide groove is disposed so as to be shifted relative to the center of the recording track in the radial direction of the disk.And
The address part consists of a pair of intermediate addresses present at positions shifted in the radial direction of the disk,
The center of the address part is a center line between the central axes of the intermediate addresses,
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.This is a substrate for an optical recording medium.
The second aspect of the present invention is characterized in that the amount of shift of the center of the address portion decreases continuously or stepwise as it goes from the outermost periphery or the innermost periphery to the central portion in each zone. 1 is a substrate for an optical recording medium according to the first aspect of the present invention.
A third aspect of the present invention is an optical recording medium substrate used for producing an optical recording medium by a predetermined manufacturing method,
The amount and direction of the center shift of the address part is
An optical recording medium is produced by the manufacturing method using a calibration substrate in which the amount of shift of the center of the address part is zero, and the center of the address part appearing in a reproduction signal when the optical recording medium is reproduced. The optical recording medium substrate according to the first aspect of the present invention is characterized in that the amount and direction of the shift cancel each other.
According to a fourth aspect of the present invention, there is provided an optical recording medium comprising a phase change type recording thin film layer on an upper surface of the optical recording medium substrate described in the first or second aspect.
The fifth aspect of the present invention is the optical recording medium according to the fourth aspect of the present invention, wherein the phase change type recording thin film layer has been initialized.
A sixth aspect of the present invention is a master for producing the optical recording medium substrate according to the first aspect,
A master for producing a substrate for an optical recording medium, wherein the guide groove and a portion corresponding to the address portion are formed on a glass master having a photoresist layer.
A seventh aspect of the present invention is a master recording apparatus for creating a master for making the optical recording medium substrate of the sixth aspect of the present invention,
A light source for exposing the photoresist layer of the glass master,
An optical modulator that modulates light of the light source according to an address signal;
A deflector for deflecting the light-modulated light,
(A) A parallel or meandering guide groove is formed for the recording track section, and (b) the light beam is shifted in the radial direction of the master for the address section section. The center of the address section 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. Thus, the master recording apparatus includes an EO deflector that deflects the light-modulated light.
The eighth aspect of the present invention is a master recording apparatus for recording information on a master for producing the optical recording medium substrate of the sixth aspect of the present invention,
A light source for exposing the photoresist layer of the glass master,
An optical modulator that modulates light of the light source according to an address signal;
A light beam output that deflects the optically modulated light beam in synchronization with the timing of the address signal and forms the address portion in a state where the center of the address portion coincides with the center of the recording track of the guide groove. A first EO deflector that
The light output from the first EO deflector is input, and (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 section corresponding to the recording track of the guide groove at least on the outermost or innermost side of each zone is in relation to the center of the recording track of the guide groove. A master recording apparatus comprising: a second EO deflector for deflecting the light beam in the radial direction of the master so as to shift relative to the radial direction of the disk.
In the ninth aspect of the present invention, the deflection direction of the light in the address section by the second EO deflector corresponds to the outermost recording track in the same zone and the innermost recording track. The master recording apparatus according to the eighth aspect, wherein the deflections corresponding to are opposite to each other.
In a tenth aspect of the present invention, the deflection amount in the address section by the second EO deflector is decreased continuously or stepwise in the respective zones from the outermost or innermost circumference to the central section. This is a master recording apparatus according to the ninth aspect of the present invention.
An eleventh aspect of the present invention is a master recording apparatus for recording information on a master for creating a substrate for an optical recording medium used for making an optical recording medium by a predetermined manufacturing method,
The direction and amount of deflection of the light beam by the second EO deflector are as follows:
An optical recording medium is produced 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 shift of the center of the address portion that appears in the reproduction signal when this is reproduced. This is a master recording apparatus according to the seventh to tenth aspects of the present invention, which has a deflection direction and a deflection amount that can cancel the amount and direction.
A twelfth aspect of the present invention is a signal generator for generating a signal for driving the EO deflector used in the master recording apparatus of the seventh aspect of the present invention,
A binary signal corresponding to the address signal is output to the optical modulator;
To the EO deflector, (a) a voltage for forming a parallel or meandering guide groove is output to the recording track section, and (b) the light beam is applied to the master disk for the address section section. The center of the address section corresponding to the recording track of at least the outermost or innermost guide groove of each zone is shifted with respect to the center of the recording track of the guide groove. The signal generator outputs a shift voltage that deflects the light-modulated light so that the light is relatively shifted in the radial direction.
A thirteenth aspect of the present invention is a signal generator for generating signals for driving the first EO deflector and the second EO deflector used in the master recording apparatus of the eighth aspect of the present invention,
A binary signal corresponding to the address signal is output to the optical modulator;
The first EO deflector deflects the optically 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. Output the voltage to be
To the second EO deflector, (a) for the recording track section, the guide groove meandering along the direction of the address pit row is formed, and (b) the address section 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 in the radial direction of the disc with respect to the center of the recording track of the guide groove. It is a signal generator that outputs an offset voltage that deflects the light beam in the radial direction of the master so as to shift relatively.
In a fourteenth aspect of the present invention, the shift voltage to the EO deflector or the second EO deflector corresponds to a voltage corresponding to the outermost recording track and an innermost recording track in the same zone. The signal generator according to the twelfth or thirteenth aspect of the present invention is characterized by having opposite polarities to each other.
In a fifteenth aspect of the present invention, the shift voltage to the EO deflector or the second EO deflector decreases continuously or stepwise in the respective zones from the outermost periphery or the innermost periphery to the central portion. A signal generator according to the twelfth or thirteenth aspect of the present invention is characterized in that
A sixteenth aspect of the present invention is a signal generator used in a master recording apparatus for recording information on a master for making a substrate for an optical recording medium used for making an optical recording medium by a predetermined manufacturing method,
The polarity and magnitude of the shift voltage to the EO deflector or the second EO deflector is prepared by the manufacturing method using the calibration substrate in which the shift amount of the address part is zero. The signal generator according to the twelfth or thirteenth aspect of the present invention is characterized in that it has a polarity and magnitude that cancels out the shift amount and direction of the address portion appearing in the reproduced signal when this is reproduced.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
The substrate, optical recording medium, and recording / reproducing apparatus of the present invention will be described below with reference to the drawings.
[0038]
As described above, the positional deviation between the center of the guide groove and the center of the address portion that occurs at the zone boundary is not remarkable in the substrate alone, but is considered to have occurred in the subsequent steps after the formation of the recording layer. .
[0039]
Therefore, the present invention measures the positional deviation between the address portion in the radial direction and the guide groove in an optical recording medium completed through each process using a calibration substrate prepared by a conventional method. Next, based on the positional deviation amount at each radial position obtained as a result of the measurement, the final light is formed by forming an address portion that is previously shifted in the direction opposite to the aforementioned positional deviation at the stage of the substrate. It is to obtain an address portion and a guide groove without misalignment in the form of a recording medium.
[0040]
The optical recording medium to which the present invention is applied has a circular shape, and a tracking guide groove for recording an information signal on the surface thereof, a part of the guide groove is interrupted, and an address pit is provided. At this time, the address pits are arranged using a ZCAV (Zone Constant Angular Velocity) method, divided into a plurality of sectors in the circumferential direction, and further divided into zones in the radial direction, and the number of sectors increases in the outer circumferential direction. The configuration.
[0041]
FIG. 1 is a diagram showing the configuration of guide grooves and address portions at zone boundaries of a substrate for an optical recording medium of the present invention. In the figure, each of the projections and depressions of the guide groove is a recording track that forms a recording area 4, and is composed of a groove track 1 and a land track 2.
[0042]
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 by about ½ track pitch with respect to the center 1c of the groove track or the center 2c of the land track. Here, the intermediate address includes a first address pit 3a positioned in front of the light beam and a second address pit row 3b positioned in the rear. The center line 3c of the center 3ac and 3bc of each address pit is defined as the center line of the intermediate address. The center line of the intermediate address is the center line of the first address pit on the outer peripheral side and the second address pit on the inner peripheral side with respect to the groove track 1, and the inner peripheral side with respect to the land track. It is located between the first address pit and the second address pit on the outer peripheral side.
[0043]
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 a different value in the radial direction in each zone.
[0044]
FIG. 1 shows the sector arrangement at the boundary 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 with respect to the center line of the guide groove is defined as d. In the zone start position, that is, in the zone (N + 1) area in the drawing, 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. In the zone end position, that is, in the zone (N) region in the figure, 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.
[0045]
FIG. 2 is a diagram showing the positional deviation amount 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. Shift to the outer circumference (+ direction) by d1 at the start position of the zone, and the shift amount decreases toward the center of the zone. The shift amount decreases to 0 at the center position, and shifts toward the inner circumference (− direction) as the zone ends. The amount of shift is d2 at the end portion.
[0046]
The value of the center position of the guide groove and the shift amount d of the intermediate address is obtained by forming a recording material layer using a calibration substrate manufactured in advance by a conventional method in which the shift amount d which is a feature of the present invention is zero. An optical recording medium is produced by a series of predetermined manufacturing processes including bonding, initialization, and the like.
[0047]
In each zone of the produced optical recording medium, the shift amount between the center of the guide groove and the center line of the intermediate address is measured. The shift amount is shifted by the same amount as the shift amount in the opposite direction, and a substrate corresponding to FIG. 2 is formed by the same process as the predetermined manufacturing process.
[0048]
The amount of deviation between the center of the guide groove and the center line of the intermediate address shown here is obtained from 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. Value.
[0049]
With the above configuration, the shift amount between the center position of the guide groove and the center line of the intermediate address generated in the manufacturing process of the optical recording medium is corrected, and the center line of the guide groove and the intermediate position in the optical recording medium completed in the final form are corrected. It becomes possible to match the center positions of the addresses. As a result, the off-track at the time of control that occurs when the recording medium is tilted in the radial direction is compensated by the track center servo using the intermediate address, so that stable recording and reproduction can be performed.
[0050]
Next, a master recording apparatus for creating a master for obtaining a substrate for an optical recording medium of the present invention will be described with reference to the block diagram of FIG. In FIG. 1, the guide groove in the recording area (section) is shown in the form of a non-modulated parallel guide groove. However, in the following embodiments of FIGS. 3 and 4, in the recording area (section), The wobble groove is a meandering guide groove.
[0051]
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 sensitizes the photoresist layer is reflected by the mirror 24 and enters the EO modulator (electro / optical element) 25. The EO modulator intensity-modulates the incident light beam according to the modulation signal corresponding to the address signal from the format control unit 26 that controls the entire mastering apparatus.
[0052]
Next, the light beam emitted from the EO modulator 25 and reflected by the second mirror 27 is a control voltage for shifting the position of the intermediate address from the format control unit 26 by 1/2 track pitch in the track direction. Accordingly, the first EO deflector 28 deflects the light beam. The first EO deflector 28 operates in the address section, but does not deflect in the recording area. The EO deflector according to the present invention corresponds to the first EO deflector.
[0053]
Next, the second EO deflector 29 deflects the light beam according to a wobble voltage for causing the guide groove from the format control unit 26 to meander according to a predetermined frequency.
[0054]
The light beam from the second EO deflector 29 is reflected by the third mirror 30, is focused on a minute spot by the objective lens 31, and irradiates the photoresist layer on the surface of the glass master disk 21.
[0055]
Although the details are omitted in the drawing, the present recording system is provided with a focus control system using an auxiliary beam for keeping the distance between the objective lens 31 and the glass master 21 constant.
[0056]
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. In accordance with a recording start signal from an external controller, recording is started. First, an address signal converted into a code signal is generated from the address generation circuit 41 at a timing synchronized with a signal indicating the rotational position from the spindle motor 23, and address modulation is performed. The modulated signal is output to the EO modulator 25 via the device 42.
[0057]
The offset voltage generation circuit 45 determines the position in the zone from the output of the track count circuit 44 that measures the number of tracks in the zone of the address signal of the address generation circuit 41, generates an offset voltage according to the result, and generates an address deflection. Output to the unit 43.
[0058]
The address deflection circuit 43 is synchronized with the timing of the modulation signal corresponding to the first address pit string and the second address pit string in accordance with the timing signal synchronized with the address modulation signal output from the address signal generator 41. Thus, a first deflection signal that is shifted equidistant from side to side with respect to the center of the guide groove is generated, and a signal obtained by superimposing the first deflection signal and the output voltage of the offset voltage circuit 45 is used as the first EO deflection. To the device 28.
[0059]
FIG. 5 shows the dependence of the output voltage of the offset voltage circuit 45 on the radial position. A positive offset voltage Vf1 is generated at the start of the zone where the zone (N) starts, and the offset voltage is lowered toward the center of the zone, and is zero at the center of the zone. Further, a negative offset voltage is applied to the zone end, and a negative Vf2 offset voltage is generated at the zone end.
[0060]
Although the method of continuously changing the offset voltage with respect to the zone position has been described here, 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.
[0061]
Also, for different zones, the offset voltage for each zone is calculated based on the value measured for the center position deviation of the intermediate address using a disk that was prototyped by a conventional method that does not change the intermediate address condition between zones. It is preferable to set.
[0062]
However, from the viewpoint of simplifying the circuit of the offset voltage generation circuit 45, when the variation of the shift amount value is small between each of the divided zones, as shown in FIG. For example, also in the zone (N + 1) on the outer peripheral side, the offset voltage of Vf1 is set at the start of the zone, zero at the center, and Vf2 at the end of the zone. As a result, the offset voltage generation circuit can be simplified.
[0063]
FIG. 6 is a diagram showing an output waveform in the address area of the deflection signal from the address deflection circuit 43. FIG. 6B shows the address deflection voltage at the center of the zone, and since the output from the offset voltage circuit 45 is zero, the voltage to be shifted equidistantly to the left and right by the 1/2 track pitch with respect to the guide groove. Is generated, and a positive deflection voltage Va is output for the first first address pit row, and a deflection voltage Vb having the same value as Va and a negative polarity is output for the subsequent second address pit row. To do.
[0064]
FIG. 6A shows the zone start end, and the offset voltage Vf1 is input from the offset voltage circuit. The address deflection circuit 43 applies the voltage (Va + Vf1) to the first address pit and the second address pit. Is output with a voltage (Vb + Vf1).
[0065]
On the other hand, FIG. 6C shows a zone termination portion, and the offset voltage Vf2 is inputted from the offset voltage circuit. The address deflection circuit 43 applies the voltage (Va + Vf2) to the first address pit and the second address. A voltage (Vb + Vf2) is output to the pit. When the deflection voltage is positive, the light beam moves in the outer peripheral direction with respect to the glass master. As a result, the center position of the intermediate address is shifted to the outer peripheral side at the start end of the zone, and is formed at the position shifted to the inner peripheral side at the end of the zone.
[0066]
Next, a second method for correcting the shift amount of the intermediate address according to the zone position will be described. In the second method, the guide groove is wobbled in the recording area, and the degree of deflection to be wobbled and the degree of deflection to be offset are approximately the same, and the pair of address pit strings is generated in comparison with this. 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 offset. Is. By doing so, it is possible to use a deflector with low cost.
[0067]
The format control unit 26 shown in FIG. 7 applies an offset to the second EO deflector used for the modulation of the groove wobble when using a wobbled guide groove. I am trying to correct it.
[0068]
Since the address deflection circuit 71 shifts the distance from the center of the guide groove by an equal distance in accordance with the timing synchronized with the address modulation signal generated from the address signal generator, the first address pit row and the second address pit Signals having the same voltage difference and different polarities are output to the first EO deflector 28 for the columns.
[0069]
The offset voltage generation circuit 73 discriminates the position in the zone by counting the number of tracks for each zone by 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 according to the result. An offset voltage is generated and output to the groove wobble circuit 72.
[0070]
The groove wobble circuit 72 generates a wobble voltage for meandering the guide groove left and right at the timing corresponding to the guide groove.
[0071]
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 region.
[0072]
FIG. 8 is a diagram showing the radial position dependency of the output voltage of the offset voltage generation circuit 73. In FIG. A positive offset voltage Vf3 is generated at the start point of the zone, and the offset voltage is lowered as it goes to the center of the zone, and is zero at the center of the zone. Further, a negative offset voltage is applied to the zone end, and a negative Vf4 offset voltage is generated at the zone end.
[0073]
FIG. 9 is a diagram showing an output waveform in the vicinity of the address area of the deflection signal from the groove wobble circuit 72. FIG. 9B shows the address deflection voltage at the center of the zone. In the area corresponding to the guide groove, a wobble voltage Vw corresponding to the wobble amount of the guide groove is output, and from the offset voltage circuit 73 in the intermediate address area. Since the output of is zero, the voltage is at a zero level.
[0074]
FIG. 9A shows the zone start end, and the offset voltage Vf3 is input from the offset voltage circuit, and the intermediate address region outputs the voltage (Vf3). On the other hand, FIG. 9C shows a zone termination portion, and the offset voltage Vf4 is input from the offset voltage circuit, and the groove wobble circuit 72 outputs a voltage (Vf4) in the intermediate address region. When the deflection voltage is positive, the light beam moves in the outer peripheral direction with respect to the glass master. As a result, the center position of the intermediate address is shifted to the outer peripheral side at the start end of the zone, and is formed at the position shifted to the inner peripheral side at the end of the zone.
[0075]
FIG. 10 is a diagram showing an example of a substrate on which intermediate addresses according to the present invention are created using a circuit in which guide grooves are wobbled and using the circuit shown in FIG. The difference from FIG. 1 is that the recording track groove track 91 and land track 92 meander, but the average track center is the center line.
[0076]
By applying the correction of the present invention, the center of the intermediate address is shifted by d91 in the outer peripheral direction at the start end of the zone, and the inner end is shifted by d92 at the end of the zone.
[0077]
With the above configuration, the guide groove and the intermediate address position in the zone can be corrected by applying an offset voltage to the second deflector for wobbling the guide groove.
[0078]
Here, the method of continuously changing the offset voltage with respect to the zone position has been described, but 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.
[0079]
Also, for different zones, the offset voltage for each zone is set based on the measured value of the center position deviation of the intermediate address using a substrate prototyped by a conventional method that does not change the intermediate address condition between zones in advance. It is preferable to set appropriately for each.
[0080]
However, from the viewpoint of simplifying the circuit of the offset voltage generating circuit 45, 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. For example, in the zone (N + 1) on the outer peripheral side, similarly to the zone (N), the offset voltage generation circuit is set to the offset voltage of Vf1 at the zone start end, zero at the center, and Vf2 at the zone end. It can be simplified.
[0081]
Next, a process of manufacturing a mold (stamper) for forming a substrate using the master recording apparatus of FIG. 3 will be described.
[0082]
The master recording apparatus is controlled by the above-described two types of format control units, and the glass master having the photoresist on the surface is exposed. Next, after removing the exposed portion by an etching process, a conductive layer is deposited on the surface. Furthermore, a metal layer such as Ni is formed on the surface by electroforming, and the metal layer is peeled off to obtain a mold.
[0083]
Next, this mold is mounted on an injection molding machine, a resin material such as polycarbonate or PMMA is injected, and the resin substrate having a guide groove and an intermediate address on the surface can be obtained by peeling from the mold.
[0084]
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 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.
[0085]
As a specific example, a ZnS-SiO2 dielectric layer as a recording layer on a substrate made of a polycarbonate resin having a thickness of 0.6 mm with a guide groove having a track pitch of 0.6 μm and an intermediate address according to the present invention, A GeSbTe phase change recording thin film layer, a ZnS-SiO2 dielectric layer, and an Al alloy reflective layer are sequentially formed by a sputtering method. On the Al alloy reflective layer, a phase change type optical recording medium is obtained by adhering a protective cover made of polycarbonate resin having a thickness of 0.6 mm using an ultraviolet curable resin layer.
[0086]
By irradiating the recording thin film layer with a high-power laser beam on a stripe having a length of 100 μm while rotating this recording medium, by performing an initialization process for changing from an amorphous state as sputtered to a crystalline state, A phase change optical recording medium is obtained.
[0087]
In the initialization step when the recording material layer is a magneto-optical recording material, light is irradiated and a magnetization direction is set to a constant direction while a magnetic field is applied.
[0088]
As a result of these processes, in the optical recording medium obtained through the above-described series of manufacturing steps using the substrate shown in FIG. 1 or FIG. 10, the center of the guide groove and the center of the intermediate address are Match. As a result, by applying tracking servo in which the light beam follows the center position of the intermediate address, stable tracking servo is possible even when the substrate or the optical head is tilted.
[0089]
Although the intermediate address provided between the land track and the groove track has been described here, the present invention is applicable to a recording medium having a guide groove and an address pit and having a different number of sectors in a zone. It is possible. For example, the center position correction can be performed in the same manner for a recording medium in a format arranged so that the center of the address pit matches the center of the guide track.
[0090]
【The invention's effect】
As described above, according to the present invention, the guide groove of the completed optical recording medium can be matched with the center position of the intermediate address, and the malfunction in the zone boundary region of the track center servo using the intermediate address is eliminated. And stable tracking servo becomes possible.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the 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 misalignment of intermediate addresses according to the present invention.
FIG. 3 is a block diagram showing 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 graph showing the zone position dependence of the offset voltage of the EO deflector according to the present invention.
FIG. 6 is a diagram showing the zone position dependence of the deflection voltage of the EO deflector according to the present invention.
FIG. 7 is a block diagram showing a configuration of a second format control unit of 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 groove wobble form of an optical recording medium.
FIG. 11 is a diagram illustrating a configuration of a substrate of an optical recording medium.
[Explanation of symbols]
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 1st EO deflector
29 2nd EO deflector
45 Offset voltage generator
d1, d2 deviation

Claims (16)

A plurality of recording tracks formed in at least guide grooves on the disc; and
An address portion formed of an address pit row provided between the recording tracks of the guide groove along the information reading direction of the recording track;
The recording track of the guide groove is divided into predetermined zones,
The center of the address portion corresponding to the recording track of at least the outermost or innermost guide groove of each zone is:
The guide groove is arranged so as to be shifted relative to the center of the recording track in the radial direction of the disk ,
The address part consists of a pair of intermediate addresses present at positions shifted in the radial direction of the disk,
The center of the address part is a center line between the central axes of the intermediate addresses,
The shift direction of the center of the address portion is opposite to each other in a shift corresponding to the outermost recording track and a shift corresponding to the innermost recording track in the same zone. Substrate for optical recording media. The amount of shift of the center of the address portion is within said each zone, the light according to claim 1, characterized in that decreasing continuously or stepwise toward the outermost periphery thereof or innermost in the central portion Substrate for recording medium. An optical recording medium substrate used for producing an optical recording medium by a predetermined manufacturing method,
The amount and direction of the center shift of the address part is
An optical recording medium is produced by the manufacturing method using a calibration substrate in which the amount of shift of the center of the address part is zero, and the center of the address part appearing in a reproduction signal when the optical recording medium is reproduced. 2. The optical recording medium substrate according to claim 1, wherein the shift amount and direction are an amount and a direction that cancel each other. Claim 1 or the upper surface of the substrate for the optical recording medium according to 2, an optical recording medium comprising the recording thin film layer of phase change type. The optical recording medium according to claim 4 , wherein the phase change recording thin film layer has been initialized. A master for producing the optical recording medium substrate according to claim 1,
A master for producing a substrate for an optical recording medium, wherein the guide groove and the portion corresponding to the address portion are formed on a glass master having a photoresist layer. A master recording apparatus for creating a master for creating the optical recording medium substrate according to claim 6 ,
A light source for exposing the photoresist layer of the glass master,
An optical modulator that modulates light of the light source according to an address signal;
A deflector for deflecting the light-modulated light,
(A) A parallel or meandering guide groove is formed for the recording track section, and (b) the light beam is shifted in the radial direction of the master for the address section section. The center of the address section 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 master recording apparatus comprising: an EO deflector for deflecting the light-modulated light. A master recording apparatus for recording information on a master for producing the optical recording medium substrate according to claim 6 ,
A light source for exposing the photoresist layer of the glass master,
An optical modulator that modulates light of the light source according to an address signal;
A light beam output that deflects the optically modulated light beam in synchronization with the timing of the address signal and forms the address portion in a state where the center of the address portion coincides with the center of the recording track of the guide groove. A first EO deflector that
The light output from the first EO deflector is input, and (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 section corresponding to the recording track of the guide groove at least on the outermost or innermost side of each zone is in relation to the center of the recording track of the guide groove. A master recording apparatus comprising: a second EO deflector for deflecting the light beam in the radial direction of the master so as to shift relative to the radial direction of the disk. The direction of light deflection in the address section by the second EO deflector is the same for the deflection corresponding to the outermost recording track and the deflection corresponding to the innermost recording track in the same zone. The master recording apparatus according to claim 8 , wherein the master recording apparatus is in the reverse direction. The amount of deflection in the address section by the second EO deflector is decreased continuously or stepwise from the outermost or innermost circumference to the central section in each zone. 9. The master recording apparatus according to 9 . A master recording apparatus for recording information on a master for creating a substrate for an optical recording medium used for making an optical recording medium by a predetermined manufacturing method,
The direction and amount of deflection of the light beam by the second EO deflector are as follows:
An optical recording medium is produced 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 shift of the center of the address portion that appears in the reproduction signal when this is reproduced. it claims 7 a deflection direction and deflection amount to offset the amount and direction master recording apparatus according to any one of 1 0. A signal generator for generating a signal for driving the EO deflector, which is used in the master recording apparatus according to claim 7 ,
A binary signal corresponding to the address signal is output to the optical modulator;
To the EO deflector, (a) a voltage for forming a parallel or meandering guide groove is output to the recording track section, and (b) the light beam is applied to the master disk for the address section section. The center of the address section corresponding to the recording track of at least the outermost or innermost guide groove of each zone is shifted with respect to the center of the recording track of the guide groove. A signal generator for outputting a shift voltage for deflecting the light-modulated light so as to be relatively shifted in the radial direction of the light. A signal generator for generating a signal for driving the first EO deflector and the second EO deflector, which is used in the master recording apparatus according to claim 8 ,
A binary signal corresponding to the address signal is output to the optical modulator;
The first EO deflector deflects the optically 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. Output the voltage to be
To the second EO deflector, (a) for the recording track section, the guide groove meandering along the direction of the address pit row is formed, and (b) the address section 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 in the radial direction of the disc with respect to the center of the recording track of the guide groove. A signal generator for outputting an offset voltage for deflecting the light beam in a radial direction of the master so as to shift relatively. The shift voltage to the EO deflector or the second EO deflector is opposite in polarity between the voltage corresponding to the outermost recording track and the voltage corresponding to the innermost recording track in the same zone. signal generating apparatus according to claim 1 2 or 1 3, characterized in that it. The shift voltage to the EO deflector or the second EO deflector decreases continuously or stepwise in the respective zones from the outermost periphery or the innermost periphery to the central portion. signal generating apparatus according to claim 1 2 or 1 3. A signal generator used in a master recording device for recording information on a master for producing a substrate for an optical recording medium used for making an optical recording medium by a predetermined manufacturing method,
The polarity and magnitude of the shift voltage to the EO deflector or the second EO deflector is prepared by the manufacturing method using the calibration substrate in which the shift amount of the address part is zero. and, a signal generating apparatus according to claim 1 2 or 1 3, characterized in this that the a polarity and magnitude to offset the amount and direction of the address portion of the shift appearing in the reproduced signal obtained by reproducing.

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