JP4249753B2 - Optical recording medium, optical recording medium manufacturing apparatus, and optical recording medium manufacturing method - Google Patents

Description

The present invention belongs to the technical field of optical recording media such as DVDs, and particularly to the technical field of optical recording media formed by meandering recording tracks.

In recent years, DVDs are widely used as large-capacity optical information recording media. In addition to a reproduction-only DVD, a standard relating to DVD-RW (DVD-Re-recordable) capable of recording and reproducing recorded information is being formulated. A groove track as a recording track is formed in a predetermined pattern on an optical disc conforming to the DVD-RW standard. The groove track is wobbled by being meandered at a constant period, and can be used as a reference signal synchronized with the rotation of the DVD-RW by extracting a wobble signal having a constant frequency during recording.

On the other hand, since recording on the DVD-RW is possible, for example, various content data recorded on the DVD-ROM can be illegally copied on the DVD-RW. Content such as images and music is usually subject to copyright protection, and it is required to protect the copyright effectively by preventing illegal copying of the DVD-RW by some method.

Therefore, the DVD-RW (Ver. 1.0) standard defines a measure for preventing illegal copying, and the DVD-RW area corresponding to the recording area where the reproduction control data or the like in the DVD-ROM is recorded. Predetermined data is embedded in advance as an emboss pit sequence (phase pit sequence). According to this, even if other reproduction control data is overwritten and recorded in such an area, the reproduction signal of the overwritten data cannot be read by interfering with the reproduction signal by the embossed pit row, substantially. Overwriting recording of other reproduction control data is disabled.

However, since the area where the embossed pit row is embedded is equivalent to the intermittent formation of the groove, the area where the output data of the wobble signal extracted from the area is recorded as a continuous groove is recorded. The output level of the wobble signal extracted from the DVD-RW is lower than the output level of the wobble signal, making it impossible to stably detect DVD-RW synchronization.

Accordingly, the present invention has been made in view of the above-described problems, and optical information that can always maintain a constant level of a wobble signal based on wobbling applied to a groove track and realize stable synchronization control. An object is to provide a recording medium.

In order to solve the above problems, the optical recording medium according to claim 1 is formed by meandering in order to extract a wobble signal having a constant frequency in an optical recording medium capable of optically recording recording information. A first area in which the recording information is recorded and a phase pit string corresponding to control data necessary for reproduction control of the recording information are meanderingly arranged on the groove track, and the phase pit string is controlled by the control A second region formed with a pit depth that enables reading of data and prevents reading of other data overwritten on the phase pit row, and a phase pit row corresponding to predetermined data meander. The phase pit row can read a prepit including address information indicating a recording position on the optical recording medium, and can be read on the phase pit row. A third area formed with a pit depth that prevents reading of other recorded data, and the meandering amplitude of the second area and the meandering amplitude of the third area are extracted from the respective areas. The wobble signal output level is set to be substantially the same as the output level of the wobble signal extracted from the first region.

According to the present invention, using the optical recording medium, recording information is recorded in the first area, and a plurality of phase pits are formed in the second area and the third area, respectively. Plays the role of preventing copying. At this time, since each region has a meandering shape, a wobble signal can be extracted. Even if the pit depth is different between the second region and the third region, the wobbling amplitude is set appropriately, so that the wobble signal substantially the same as that in the first region serving as a reference is used. The output level can be obtained. Therefore, the output level of the wobble signal can always be kept constant in different areas of the optical recording medium, and can be used for highly accurate synchronization control.

The optical recording medium according to claim 2 is the optical recording medium according to claim 1, wherein the prepits are formed at least in the first area and the third area. To do.

According to the present invention, in addition to the same operation as that of the first aspect of the invention, the prepit is formed in a region other than the second region. Therefore, even when the phase pits of the second region and the third region are formed with greatly different pit depths according to the presence or absence of the pre-pits, the wobble signal output level is kept the same as described above. Can do.

The optical recording medium according to claim 3 is the optical recording medium according to claim 2, wherein the pit depth of the third region is set to be the same as the groove track depth of the second region. It is characterized by that.

According to this invention, in addition to the operation similar to that of the first and second aspects of the invention, the groove track depth in the first region and the pit depth in the third region are the same. Therefore, the first region and the third region can keep the output level of the wobble signal the same as described above only by changing only the meandering amplitude of each other.

The optical recording medium according to claim 4 is the optical recording medium according to claim 3, wherein the first region has a groove track depth of 30 nm, and the second region has pits. The depth is set to 80 nm, the average duty of the pit row is set to about 50%, the meandering amplitude is set to about 2.7 times the meandering amplitude of the first region, and the third region has a pit depth of 30 nm, The average duty of the pit row is set to about 80%, and the meandering amplitude is set to about 1.3 times the meandering amplitude of the first region.

According to this invention, specific conditions are given to the invention according to claim 3. Therefore, it is possible to give a design condition suitable for a configuration using a DVD-RW.

The optical recording medium according to claim 5 is the optical recording medium according to claim 2, wherein the meandering amplitude of the third region is set to be the same as the meandering amplitude of the first region. It is characterized by.

According to the present invention, in addition to the same operation as that of the first and second aspects, the meandering amplitude of the first region and the meandering amplitude of the third region are the same. Therefore, the output level of the wobble signal can be kept the same as described above only by changing the groove track depth of the first region and the pit depth of the third region.

The optical recording medium according to claim 6 is the optical recording medium according to claim 5, wherein the first region has a groove track depth of 30 nm, and the second region has a pit. The depth is set to 80 nm, the average duty of the pit row is set to about 50%, and the meandering amplitude is set to about 2.7 times the meandering amplitude of the first region. The third region has a pit depth of 50 nm, The average duty of the pit row is set to approximately 80%, and the meandering amplitude is set to be the same as the meandering amplitude of the first region.

According to the present invention, specific conditions are given to the invention according to claim 5. Therefore, it is possible to give a design condition suitable for a configuration using a DVD-RW.

The optical recording medium manufacturing apparatus according to claim 7 is an optical recording medium manufacturing apparatus that manufactures an optical recording medium capable of optically recording recording information by using an optical disc master, using a wobble signal having a constant frequency. A first area forming means for forming a first area on which the recording information is recorded, which is cut by the modulated optical beam while meandering the groove track while meandering the groove track, and modulated by the wobble signal Using a light beam, it is possible to read out the control data from the phase pit string corresponding to the control data necessary for reproduction control of the recorded information, and read out other data overwritten on the phase pit string. A second region forming means for forming a second region by cutting while meandering the optical disc master with a pit depth that prevents Using a light beam modulated by the wobble signal, it is possible to read a prepit including address information indicating a recording position on the optical recording medium from a phase pit row corresponding to predetermined data, and the phase pit A third region forming means for forming a third region by cutting while meandering the optical disc master with a pit depth that prevents reading of other data overwritten on the row; In the area forming means and the third area forming means, the output level of the wobble signal extracted from the respective areas at the time of reproduction of the optical recording medium manufactured using the optical disc master is extracted from the first area. The degree of modulation of the light beam by the wobble signal is set so that the output level of the wobble signal is substantially the same. The features.

The optical recording medium manufacturing apparatus according to claim 9 is an optical recording medium manufacturing method in which an optical recording medium capable of optically recording recording information is manufactured using an optical disc master. A first area forming step of forming a first area in which the recorded information is recorded by cutting the optical disk master while meandering a groove track using a light beam modulated by a signal, and modulating by the wobble signal The phase pit sequence corresponding to the control data necessary for the reproduction control of the recorded information is read using the optical beam, and the control data can be read, and other data overwritten and recorded on the phase pit sequence The second region forming process for forming the second region by cutting while meandering the optical disc master according to the pit depth that hinders reading And using a light beam modulated by the wobble signal, a phase pit sequence corresponding to predetermined data can be read out from a prepit including address information indicating a recording position on the optical recording medium, and A third region forming step of forming a third region by cutting while meandering the optical disc master with a pit depth that prevents reading of other data overwritten on the phase pit row, and In the second region forming step and the third region forming step, the output level of the wobble signal extracted from each of the regions when the optical recording medium manufactured using the optical disc master is reproduced is the first region forming step. The degree of modulation of the light beam by the wobble signal is set so that it is substantially the same as the output level of the wobble signal extracted from the area. Characterized in that it.

According to the invention described in each of claims 7 and 9, the first area where the groove track is cut and the second area where the plurality of phase pits are provided are provided on the optical disc master used for manufacturing the optical recording medium. And the third region are formed. At this time, since modulation is performed with a wobble signal of a light beam used for forming each region, a meandering pattern is formed for each region. Even if the pit depth to be cut is different between the second area and the third area, the degree of modulation is set appropriately, so that it is substantially the same as the case of the reference first area. Can be formed with a meandering amplitude of Therefore, the optical recording medium manufactured using the stamper can always keep the output level of the wobble signal constant in different regions, and can perform highly accurate synchronous control.

The optical recording medium manufacturing apparatus according to claim 8 is the optical recording medium manufacturing apparatus according to claim 7, wherein the first area forming means and the third area forming means form the pre-pits. It is characterized by that.

The optical recording medium manufacturing apparatus according to claim 10 is the optical recording medium manufacturing method according to claim 9, wherein the pre-pits are formed in the first region forming step and the third region forming step. It is characterized by that.

According to the eighth and tenth aspects of the present invention, in addition to the same action as that of the seventh and ninth aspects, the prepits are formed in the first and third regions. Therefore, even if the phase pits of the second region and the third region are formed with different pit depths depending on the presence or absence of the pre-pits, the optical type manufactured using the stamper as described above The recording medium can always keep the output level of the wobble signal constant in different areas.

According to the present invention, the level of the wobble signal extracted by meandering each area on the optical recording medium provided with the first area, the second area, and the third area is always kept constant. Synchronous control can be performed stably.

A preferred embodiment of the present invention will be described with reference to FIGS. In the following, an embodiment in which the present invention is applied to a DVD-RW as an optical recording medium capable of recording record information will be described.

FIG. 1 is a plan view of a DVD-RW according to this embodiment, and is a plan view of the DVD-RW at the time of shipment. As shown in FIG. 1, the DVD-RW 1 according to the present embodiment has a clamp hole used for fixing to a spindle motor of an information recording apparatus (not shown) that records recording information on the DVD-RW 1 at the time of shipment. CH is opened in the center. Also, the DVD-RW 1 has a second area (reproduction-only area RA) in which emboss pit rows corresponding to control data necessary for reproduction control of recorded information are embedded, and an emboss pit row corresponding to predetermined data. The embedded third area (impossible area UA) is formed concentrically. According to the present embodiment, control data can be read from the embossed pit string in the reproduction-only area RA, and predetermined data cannot be read from the embossed pit string in the impossible area UA. The read-only area RA and the impossible area UA are areas on the DVD-RW 1 corresponding to a recording area for DVD-ROM playback control information and the like in order to prevent illegal copying of the DVD-RW 1 as described above. This is an area where other control data cannot be overwritten.

In the information recording apparatus, after the initialization process is first performed when recording information on the DVD-RW 1, the DVD-RW 1 has an inner peripheral side as shown by a broken line in FIG. A control information area RI, a lead-in area L1, and a recording area DA as a first area of the present invention are formed.

In the control information area R1, control information used for recording and reproducing the recording information with respect to the DVD-RW1 is recorded at the time of initialization. Specific control information includes, for example, setting information of the intensity of a light beam for recording and reproduction, recording control information used for recording, and the like. In the lead-in area L1, start information indicating the start of recording and reproduction is recorded at the time of initialization. The recording area DA is an area for actually recording recording information such as various contents on the DVD-RW 1. In FIG. 1, the partition lines of the read-only area RA and the impossible area UA that are already formed at the time of shipment are indicated by solid lines, and the control information area RI, lead-in area LI, recording area formed after initialization are shown. Each partition line of DA is distinguished by a broken line.

At the time when the above initialization process for the DVD-RW 1 is completed, both the reproduction-only area RA and the impossible area UA are included in the lead-in area LI. Further, when recording of the recording information on the entire DVD-RW 1 is completed, a lead-out area in which end information indicating the end of recording is recorded is formed in the outermost peripheral portion of the recording area DA.

Next, FIG. 2 is a cross-sectional view showing the structure of the DVD-RW 1 in which pre-pits described later are formed. 2A is a perspective view showing the structure of the DVD-RW 1 in the recording area DA, and FIG. 2B is a cross-sectional view of the groove track as viewed from the direction of the arrow in FIG. .

In the DVD-RW 1, the pre-pits 4 are formed on the land track 3 in the area excluding the read-only area RA at the time of shipment. In this pre-pit 4, address information indicating a recording position when recording on the DVD-RW 1 is recorded as pre-information.

Similarly, the groove track 2 of the DVD-RW 1 is wobbled to generate a wobble signal used for synchronous control of the entire recording operation such as rotation control at the time of shipment. That is, the groove track 2 meandering at a constant cycle is formed in advance on the DVD-RW 1.

2A and 2B, a DVD-RW 1 is a phase change type optical disc having a recording layer 11 made of a phase change thin film. A groove track 2 as a recording track and a guide adjacent to the groove track 2 are shown. Land tracks 3 as tracks are alternately formed on the substrate 9. The groove track 2 is irradiated with a light beam B having a wavelength of 650 nm during reproduction or recording, and the light beam B can be guided to the groove track 2 by the action of the land track 3.

2B, the groove track 2 has a cross-sectional structure in which a resin layer 9A, a reflective layer 6, a protective layer 8, a recording layer 11, a protective layer 5, and a protective film 7 are sequentially laminated on a substrate 9. It has become. The protective layers 5 and 8 are disposed so as to sandwich the recording layer 11 and have a function of protecting the recording layer 11. The reflective layer 6 plays a role of reflecting the irradiated light beam B. The protective film 7 and the resin layer 9A are provided to protect each of the above layers from the outside air.

At this time, the depth of the groove track 2 is set to 20 nm or more and 35 nm or less at the position of the recording layer 11, and the interval between the center lines of two adjacent groove tracks 2 is set to 0.74 μm.

On the other hand, as described above, pre-pits 4 corresponding to the pre-information are formed on the land track 3 at the time of shipment. When the information recording apparatus records the record information on the DVD-RW 1, the pre-pit 4 is detected and pre-recorded pre-information is acquired as will be described later. Based on this, the optical beam B is recorded. The optimum output and the like are set, and recording is performed at a predetermined recording position of the recording information based on the address information as pre-information.

Further, as shown in FIG. 2A, the groove track 2 is formed in a meandering manner and is subjected to the wobbling. The wobble signal extracted based on the wobbling of the groove track 2 is a periodic signal having a relatively low frequency (specifically, 140 kHz). Moreover, since the wobbling amplitude as the meandering amplitude of the groove track 2 is kept constant, the level of the extracted wobble signal is also constant. When the information recording apparatus records the record information on the DVD-RW 1, the wobble signal is extracted from the detection signal from the groove track 2, and the overall operation of the DVD-RW 1 is controlled using this as a synchronization reference.

Here, as shown in FIG. 2A, when recording information is recorded on the DVD-RW 1, the light beam B is irradiated so as to trace the center of the groove track 2, and the phase change is performed on the groove track 2. Recording information is recorded by forming pits in a predetermined pattern.

At this time, the light spot SP formed by the light beam B has such a size that a part of the light spot SP can be irradiated onto the land track 3 in addition to the groove track 2 as shown in FIG. Is set to the correct position. Then, the pre-information carried by the pre-pit 4 is obtained by a push-pull method (radial push-pull method using a photodetector divided by a dividing line parallel to the rotation direction of the DVD-RW 1) using reflected light of the light spot SP. Detected. The tracking servo control for causing the light beam B to follow the groove track 2 is also performed based on the push-pull method.

Next, the structure of the read-only area RA formed on the DVD-RW 1 will be described with reference to FIGS. FIG. 3 is an enlarged plan view showing a structure near the boundary between the reproduction-only area RA and the impossible area UA. 4A is a cross-sectional view of the read-only area RA viewed from the AA ′ portion in FIG. 3, and FIG. 4B is a read-only area RA viewed from the BB ′ portion in FIG. FIG. 4A is a cross-sectional view corresponding to FIG. 2A, and FIG. 4B is a cross-sectional view corresponding to FIG.

In the reproduction-only area RA, the continuous groove track 2 and land track 3 as shown in FIG. 2 are not formed. On the other hand, as shown in FIG. 3, a plurality of phase pits PI as embossed pit rows carrying reproduction control information and the like used when reproducing the DVD-RW 1 are formed in the reproduction-only area RA. Based on this phase pit PI, the level of reflected light changes due to diffraction that occurs when the light beam B is irradiated, so that it is possible to determine the presence or absence of the phase pit PI and detect reproduction control information or the like. Become.

As shown in FIG. 3, pit rows intermittently arranged along the center line CL are meandered by the phase pits PI formed in the read-only area RA, and wobbling is performed at a constant period. The period in which the pit row of the phase pit PI meanders is set to the same period as the wobbling period of the groove track 2 shown in FIG. Further, the wobbling amplitude of the pit row of the phase pit PI is appropriately set in consideration of the level of the wobble signal as will be described later. Thus, also when tracing the pit row of the phase pits PI in the reproduction-only area RA, the wobble signal can be extracted.

Here, the depth of the phase pit PI in the read-only area RA allows the control data to be read and prevents reading of other control data overwritten on the phase pit row. The position is 60 nm or more and 90 nm or less. Further, the distance between the center lines of the phase pits PI adjacent to each other in the radial direction of the DVD-RW 1 is 0.74 μm as in the case of the groove track 2. In this embodiment, the phase of the wobble signal based on the pit row of the phase pits PI in the read-only area RA is set to the same level as the wobble signal based on the wobbling applied to the groove track 2. Although the depth of the pit PI is set appropriately, details will be described later.

Note that the portion where the phase pits PI are not formed in the read-only area RA is completely flat as shown in FIG.

In addition, the prepit 4 is not formed in the reproduction-only area RA. This is because the phase pit PI and the pre-pit 4 are formed at the same depth as will be described later, and if they are present in the same region, they interfere with each other optically, making it difficult to detect both. is there.

Next, the structure of the impossible area UA formed on the DVD-RW 1 will be described with reference to FIG. In the above-mentioned impossible area UA, as shown in FIG. 3, the continuous groove track 2 and land track 3 are not formed as in the reproduction-only area RA. On the other hand, in the impossible area UA, a plurality of phase pits PI 'as embossed pit rows are formed and correspond to predetermined data modulated by 8-16. Further, wobbling is also applied to the pit row of the phase pit P ′.

Here, the depth of the phase pit PI ′ in the impossible area UA enables reading of the pre-pit 4 and prevents reading of other control data overwritten on the phase pit row. The position is 20 nm or more and 35 nm or less, which is the same as the groove track 2. When the recording layer 11 in the impossible area UA configured in this way is irradiated with a light beam to form a phase change pit, the phase change occurs due to interference with the phase pit PI ′ above the recording layer 11. The contents of the pit cannot be detected.

In the impossible area UA, address information is recorded by the prepit 4. Therefore, the recording position on the DVD-RW 1 can be grasped by the information recording apparatus before the recording light beam B reaches the recording area DA as the DVD-RW 1 rotates during recording.

Next, a recording format in the DVD-RW 1 according to the present embodiment will be described with reference to FIG. FIG. 5 is a diagram showing a part of the recording format of the DVD-RW 1 after the lead-in area LI and the recording area DA are formed.

As shown in FIG. 5, after the initialization process is performed, the lead-in area LI includes an initial zone IZ, a reference code zone RZ, and a first buffer zone B1 from the inner periphery side. The reproduction-only area RA and the impossible area UA described above and the second buffer zone B2 are formed. Among these, zero data is recorded in all bit strings in the initial zone IZ, the first buffer zone B1, and the second buffer zone B2. In addition, a reference code including the start information and the like is recorded in the reference code zone RZ.

As shown on the left side of FIG. 5, the address information carried by the pre-pit 4 is set so that the initial zone IZ, the reference code zone RZ, and the first buffer zone B1 are sequentially incremented from the inner peripheral side. On the other hand, the impossible area UA and the second buffer zone B2 are set so as to be sequentially decremented from the innermost periphery of the recording area DA (the outermost periphery of the second buffer zone B2). As described above, no address information is set in the read-only area RA in which the pre-pit 4 is not formed, so that the address information is set discontinuously before and after that.

On the other hand, the sector number corresponding to the DVD format is set as shown on the right side of FIG. That is, for the read-only area RA, the sector number is recorded in advance by the phase pit PI at the time of shipment, whereas in the lead-in area LI excluding the read-only area RA and the impossible area UA, The sector number to be arranged in is set. At this time, with respect to the impossible area UA, the sector number is set so as to continuously change between the innermost peripheral portion and the outermost peripheral portion.

Next, the relationship between the depth of the phase pit PI and the optical characteristics in the read-only area RA will be described with reference to FIG. FIG. 6 shows the experimental results regarding the relationship between the output level of the detection signal detected by the phase pit PI and the output level of the tracking error signal based on the push-pull method with respect to the depth of the phase pit PI in the read-only area RA. FIG.

As described above, in order to detect the sector information recorded by the phase pits while accurately performing the tracking servo control in the read-only area RA, both the detection signal and the tracking error signal have a good output level. Need to be detected. In FIG. 6, in order to make the output levels of both the detection signal and the tracking error signal within an allowable range, the depth of the phase pit PI needs to be set to 60 nm or more and 90 nm or less (B region in FIG. 6). If the depth of the phase pit PI is set to 70 nm or more and 80 nm or less (A region in FIG. 6), the output levels of both the detection signal and the tracking error signal can be further optimized.

Next, a cutting apparatus for manufacturing the DVD-RW 1 having the above structure will be described with reference to FIG. FIG. 7 is a block diagram showing a schematic configuration of the cutting apparatus according to the present embodiment.

As shown in FIG. 7, the cutting apparatus according to this embodiment includes a land data generator 20, a parallel / serial converter 21, a preformat encoder 22, a clock signal generator 23, a laser generator 24, , Optical modulator 25, objective lens 26, spindle motor 29, rotation detector 30, rotation servo circuit 31, feed unit 32, position detector 33, feed servo circuit 34, CPU 40, groove A data generator 50, a wobble signal generator 51, a variable gain amplifier 52, and a switch 53 are included.

The optical disc master is composed of a glass substrate 27 and a resist 28 coated on the glass substrate 27. The resist 28 is exposed to light beams BG and BL, which will be described later, to form pits having shapes corresponding to changes in the intensity of the light beams BG and BL.

In FIG. 7, the land data generator 20 outputs parallel data corresponding to the pattern of the prepits 4 formed on the land track 3 under the control of the CPU 40. The output parallel data is converted into serial data by the parallel / serial converter 21. The serial data is input to the preformat encoder 22, and the land track 3 and the prepit 4 are actually formed on the optical disc master based on the preformatting clock signal supplied from the clock signal generator 23. A land data signal SL is generated and output to the optical modulator 25.

On the other hand, the groove data generator 50 generates groove data corresponding to the pattern of the groove track 2 or the phase pits PI and PI ′ to be formed in advance under the control of the CPU 40 and outputs it as a control signal to the switch 53. .

The wobble signal generator 51 generates a wobble signal for wobbling the groove track 2. The wobble signal is amplified by the variable gain amplifier 52 with a predetermined wobble gain based on the control of the CPU 40 and then output to the switch 53.

As described above, the switch 53 receives the wobble signal to which the gain is applied and the ground level, and performs switching control based on the groove data output from the groove data generator 50. As a result, a groove data signal SG for actually forming the shape of the groove track 2 on the optical disk master is output to the optical modulator 25.

The laser generator 24 emits a first light beam BG for forming a groove track and a second light beam BL for forming a prepit 4 of the land track 3 to the optical disc master. In the optical modulator 25 described above, the first light beam BG is modulated based on the groove data signal SG, while the second light beam BL is modulated based on the land data signal SL. Is done. Further, the laser power in the laser generator 24 is controlled at a predetermined timing according to the control of the CPU 40. Then, the light beams BG and BL are condensed on the optical disc master via the objective lens 26.

At this time, the spindle motor 29 rotates the optical disc master, and the rotation detector 30 detects the rotation of the optical disc master. Thereby, the rotation servo circuit 31 controls the rotation of the optical disk master and outputs a rotation pulse synchronized with the rotation.

The position detector 33 detects the position of the feed unit 32 and outputs the detection signal to the feed servo circuit 34. The feed servo circuit 34 acquires the position information of the feed unit 32 based on the detection signal from the position detector 33, and thereby servo-controls the movement of the feed unit 32.

By performing the above-described operation, a concave / convex shape corresponding to the spiral track and the embossed pit row is formed on the optical disc master, and a stamper disc as a die for manufacturing the optical disc based on the optical disc master is provided. Will be created. Thereafter, a replication process using a stamper disk is executed, and DVD-RW1 as a replica disk according to the present invention is mass-produced.

Next, an optical disk master cutting process performed in the cutting apparatus according to the present embodiment will be described with reference to flowcharts shown in FIGS. This process is mainly performed by the CPU 40 in accordance with a control program stored in a memory means (not shown).

As shown in FIG. 8, when processing in the cutting device is started, initial setting of the wobble gain in the variable gain amplifier 52 and the laser power in the laser generator 24 is performed (step S1). Here, the wobble gain when the groove track 2 is formed with a standard wobbling amount is set, and the laser power is set so that the depth of the groove track 2 is 30 nm.

Subsequently, the formation of the pre-pits 4 of the groove track 2 and the land track 3 is started on the optical disc master (step S2). That is, while controlling the rotation servo circuit 31 and the feed servo circuit 34, the laser generator 24 is driven and controlled to start irradiation of the optical disc master with the first light beam BG and the second light beam BL.

Then, with reference to the address information to be recorded in the prepit 4, it is determined whether or not the reproduction-only area RA has been reached (step S3). As shown in FIG. 5, the start address 002F20h of the reproduction-only area RA may be detected. If the result of determination in step S3 is that the reproduction-only area RA has been reached (step S3; YES), the reproduction-only area RA is formed (step S4).

Here, the specific process of step S4 will be described with reference to FIG. When the process for forming the reproduction-only area RA shown in FIG. 9 is started, the pre-pit 4 is not formed in the reproduction-only area RA as described above. Therefore, the irradiation of the second light beam BL by the laser generator 24 to the optical disc master is stopped.

Next, the wobble gain is set so as to match the wobbling amplitude of the phase pit PI in the reproduction-only area RA (step S12). Further, the laser power is set so as to match the depth of the phase pit PI in the reproduction-only area RA (step S13). The specific setting of the wobbling amplitude and the phase pit PI depth in the reproduction-only area RA will be described later.

Next, the sector number to be recorded using the phase pit PI in the reproduction-only area RA is set to 002F200h (step S14). As shown in FIG. 5, this corresponds to the top sector number of the reproduction-only area RA.

Next, the formation of the phase pit PI in the reproduction-only area RA is started (step S15). As a result, a pit row of the phase pits PI is formed with a predetermined wobbling amplitude and pit depth in the reproduction-only area RA.

After step S15, it is determined whether or not the impossible area UA has been reached by referring to the sector number (step S16). As shown in FIG. 5, the sector number corresponding to the start address 002FD0h of the impossible area UA may be detected. As a result of the determination in step S16, when the impossible area UA is reached (step S16; YES), the process proceeds to step S5 in FIG.

Next, as shown in FIG. 8, the formation process of the impossible area UA is performed (step S5). Here, the specific process of step S5 will be described with reference to FIG. When the formation process of the impossible area UA shown in FIG. 10 is started, it is necessary to form the prepit 4 in the impossible area UA as described above, so the address recorded by the prepit 4 is set to 002FD0h. As described above, this corresponds to the leading address of the impossible area UA.

Then, the recording of the pre-pit 4 that has been paused in step S11 is resumed (step S22). Thereafter, the second optical beam BL is applied to the optical disc master by the laser generator 24.

Next, the wobble gain is set so as to match the wobbling amplitude of the phase pit PI 'in the impossible area UA (step S23). Further, the laser power is set so as to match the depth of the phase pit PI 'in the reproduction-only area RA (step S24). The specific setting of the wobbling amplitude and the depth of the phase pit PI ′ in the impossible area UA will be described later.

Next, formation of the phase pit PI 'in the impossible area UA is started (step S25). As a result, in the impossible area UA, a pit row of the phase pit PI 'is formed with a predetermined wobbling amplitude and depth, and a pre-pit 4 carrying address information is formed adjacent thereto.

After step S25, it is determined whether or not the second buffer zone B2 has been reached while referring to the address information (step S26). As shown in FIG. 5, it is only necessary to detect the start address 002FE0h of the second buffer zone B2. If the result of determination in step S26 is that the second buffer zone B2 has been reached (step S26; YES), the flow proceeds to step S6 in FIG.

Next, as shown in FIG. 8, the wobble gain and laser power whose settings have been changed as described above are returned to the initial setting state similar to step S1 (step S6). Thereafter, a groove track 2 having a standard wobbling amount and a depth of 30 nm is formed.

After step S6, it is determined whether or not a predetermined recording end position on the DVD-RW 1 has been reached while referring to the address information (step S7). As a result, when the recording end position is reached (step S7; YES), the cutting process of FIGS.

Next, in the present embodiment, an example of a specific configuration related to the reproduction-only area RA and the impossible area UA will be described. In the following embodiments, the wobbling amplitude and the pit depth for the phase pits PI and PI ′ should be appropriately set in order to optimize the output level of the wobble signal in the read-only area RA and the impossible area UA. It is a parameter.

First, the simulation result about the relationship between each said parameter and the output characteristic of a wobble signal is demonstrated using FIG.11 and FIG.12. FIG. 11 is a simulation example in which the relationship between the output level of the tracking error signal based on the push-pull method and the pit depth (groove depth) is obtained. FIG. 12 is a simulation example in which the relationship between the wobble signal output level and the wobbling amplitude is obtained.

In FIG. 11, the characteristics of the groove portion where the groove track 2 is formed and the two types of pit rows including phase pits having a duty of 80% and 50% instead of the groove track 2 are shown in comparison. Note that the three characteristics in FIG. 11 correspond to the case where the wobbling amplitude is a constant value. In FIG. 11, the vertical axis represents the output level of the tracking error signal. However, since the output levels of the wobble signal and tracking error signal are proportional to each other, the same curve can be obtained even if the vertical axis of FIG. It becomes.

Here, the duty of the pit row represents an average value of the ratios of the phase pit formation portions in the length in the track direction. In the read-only area RA in which sector information and the like are recorded, since the pit arrangement has no degree of freedom, a duty of approximately 50% is assumed. On the other hand, in the impossible area UA in which the pit arrangement is random, the duty can be adjusted to some extent, and a duty of 80% is assumed as a condition closer to the groove portion. In the case of the groove portion, the duty can be regarded as 100%.

As can be seen from FIG. 11, when the pit depth (groove depth) is the same, the output level also decreases as the duty decreases. This is because the phase change given to the irradiated light beam is reduced by reducing the phase pit portion.

In FIG. 11, the groove depth of the groove portion is set to 30 nm corresponding to the standard. In the reproduction-only area RA, the depth of the phase pit PI is set to 80 nm in a suitable range based on the optical characteristics shown in FIG. On the other hand, in the impossible area UA, it is necessary to reduce the pit depth of the phase pit PI ′ in consideration of the detection performance of the pre-pit 4. Here, it is assumed that the depth of the phase pit PI 'in the impossible area UA is set to two types of 30 nm and 50 nm. In FIG. 11, the positions of the set pit depths (groove depths) are indicated by dotted lines.

Next, FIG. 12 shows a change in the output level of the wobble signal when the wobbling amplitude is changed when the pit depth (groove depth) is set to the above condition. The case where 30 nm is set as the depth of the phase pit PI 'in the impossible area UA corresponds to the condition A, and the case where it is set to 50 nm corresponds to the condition B.

As is apparent from FIG. 12, the wobbling amplitude and the output level of the wobble signal are in a proportional relationship. Further, corresponding to the characteristics shown in FIG. 11, even when the wobbling amplitude is the same, the wobble signal extracted in the order of the condition B of the groove portion and the impossible area UA, the condition A of the impossible area UA, and the reproduction-only area RA. The output level decreases. Therefore, in this embodiment, a decrease in the output level of the wobble signal due to the difference in the above conditions as shown in FIG. 12 is compensated by adjusting the wobbling amplitude.

Based on the above discussion, two examples of the DVD-RW according to the present embodiment will be described with reference to FIGS. FIG. 13 is a diagram showing the configuration of the first embodiment, and FIG. 14 is a diagram showing the configuration of the second embodiment.

In the two embodiments shown in FIGS. 13 and 14, the condition of the groove portion and the condition of the reproduction-only area RA are common. That is, the groove depth is set to 30 nm, and the wobbling amplitude X is set to a predetermined amount as a standard. The phase pit PI in the reproduction-only area RA has a pit depth set to 80 nm and a wobbling amplitude set to 2.7X under the condition of a duty of 50%.

In the first embodiment shown in FIG. 13, the phase pit PI ′ in the impossible area UA has a pit depth of 30 nm and a wobbling amplitude of 1.3 × under the condition of a duty of 80%. Is set. At this time, as shown in the lower part of FIG. 12, the wobble signal extracted in the impossible area UA and the reproduction-only area RA is similar to the output level Y of the wobble signal output level Y extracted in the groove section. I understand that

Next, in the second embodiment shown in FIG. 14, the phase pit PI ′ in the impossible area UA is set to a pit depth of 50 nm and a wobbling amplitude to X under the condition of a duty of 80%. Is done. Also in this case, as shown in the lower part of FIG. 13, the output level Y of the wobble signal extracted in the impossible area UA and the reproduction-only area RA is similar to the output level Y of the wobble signal extracted in the groove section. It turns out that it becomes.

Thus, both the first and second embodiments can make the output level of the wobble signal in each region substantially the same. In the first embodiment, a common pit depth (groove depth) of 30 nm is set for the groove portion and the impossible area UA. On the other hand, in the second embodiment, a common wobbling amplitude X is set for the groove portion and the impossible area UA.

As described above, according to the DVD-RW 1 according to the present embodiment, conditions such as the pit depth and the wobbling amplitude are provided even when the reproduction-only area RA and the impossible area UA for preventing illegal copying are provided. By setting appropriately, the output level of the wobble signal based on the wobbling of each region can be kept constant. As a result, it is possible to stabilize the synchronization control when recording / reproduction is controlled using the wobble signal.

In addition, this invention is not limited to embodiment mentioned above. For example, in the above-described embodiment, the DVD-RW has been described as an optical recording medium capable of optically recording recording information. However, an optical recording medium based on another format such as a DVD-R may be used. The present invention is applicable.

Further, according to the above-described cutting apparatus as the optical recording medium manufacturing apparatus, the pre-pit 4 and the groove track 2 are respectively cut on the optical disk master by different light beams BG and BL. The prepit 4 can also be formed by greatly diffracting one light beam in the radial direction of the disk by 25. Further, according to such an optical recording medium manufacturing apparatus, the depth of the phase pit is changed by adjusting the power of the light beam, but it is also possible to perform them under the control of the optical modulator 25.

It is a top view of DVD-RW concerning this embodiment. It is a figure which shows the structure of DVD-RW in which the prepit was formed, (a) is a perspective view, (b) is sectional drawing. It is a plane enlarged view which shows the structure of a read-only area | region and an impossible area | region. 4A and 4B are cross-sectional views showing the structure of a read-only area, where FIG. 4A is a cross-sectional view of a portion where phase pits are formed, and FIG. It is a figure which shows a part of recording format in DVD-RW which concerns on this embodiment. It is a figure which shows the experimental result corresponding to this embodiment. It is a block diagram showing a schematic structure of a cutting device concerning this embodiment. It is a flowchart which shows the optical disk master cutting process performed in the cutting apparatus which concerns on this embodiment. It is a flowchart which shows the formation process of a read-only area | region among the cutting processes of the optical disk original disk performed in the cutting apparatus which concerns on this embodiment. It is a flowchart which shows the formation process of an impossible area among the cutting processes of the optical disk original disc performed in the cutting apparatus which concerns on this embodiment. It is a figure which shows the example of a simulation which calculated | required the relationship of the output level of the tracking error signal with respect to pit depth (groove depth) among the simulation results corresponding to this embodiment. It is a figure which shows the example of a simulation which calculated | required the relationship of the output level of the wobble signal with respect to a wobbling amplitude among the simulation results corresponding to this embodiment. It is a figure which shows the structure of the 1st Example in DVD-RW which concerns on this embodiment. It is a figure which shows the structure of the 2nd Example in DVD-RW which concerns on this embodiment.

Explanation of symbols

1 ... DVD-RW
2 ... groove track 3 ... land track 4 ... pre-pits 5, 8 ... protective layer 6 ... reflective layer 7 ... protective film 9 ... substrate 9A ... resin layer 11 ... recording layer 20 ... land data generator 21 ... parallel / serial generator 22 ... preformat encoder 23 ... clock signal generator 24 ... laser generator 25 ... optical modulator 26 ... objective lens 27 ... glass substrate 28 ... resist 29 ... spindle motor 30 ... rotation detector 31 ... rotation servo circuit 32 ... feed unit 33 ... Position detector 34 ... Feed servo circuit 40 ... CPU
50 ... Groove data generator 51 ... Wobble signal generator 52 ... Variable gain amplifier 53 ... Switch CH ... Clamp hole RA ... Read-only area (second area)
UA ... impossible area (third area)
RI ... control information area LI ... lead-in area DA ... recording area (first area)
B ... light beam BG ... first light beam BL ... second light beam SP ... light spot PI, PI '... phase pit IZ ... initial zone RZ ... reference code zone B1 ... first buffer zone B2 ... second buffer zone

Claims (10)

In an optical recording medium capable of optically recording recording information, a first area in which the recording information is recorded on a groove track formed in a meandering manner to extract a wobble signal having a constant frequency, and the recording Other data recorded in an overwritten manner on the phase pit row, in which the phase pit row corresponding to the control data necessary for information reproduction control is arranged in a meandering manner, and the phase pit row can read the control data. And a phase pit row corresponding to predetermined data are arranged in a meandering manner, and the phase pit row indicates a recording position on the optical recording medium. It is possible to read the pre-pit including the address information shown, and it is formed with a pit depth that prevents reading of other data overwritten on the phase pit row. A meandering amplitude of the second region and a meandering amplitude of the third region, the output level of the wobble signal extracted from each region is extracted from the first region. An optical recording medium, wherein the optical recording medium is set to be substantially the same as an output level of a wobble signal. The optical recording medium according to claim 1, wherein the pre-pits are formed at least in the first area and the third area. 3. The optical recording medium according to claim 2, wherein the pit depth of the third area is set to be the same as the depth of the groove track of the second area. The first region has a groove track depth of 30 nm, the second region has a pit depth of 80 nm, an average pit row duty of approximately 50%, and a meandering amplitude of the first region. Each of the third regions is set to approximately 2.7 times the meandering amplitude, the pit depth is 30 nm, the average duty of the pit row is about 80%, and the meandering amplitude is about 1 of the meandering amplitude of the first region. The optical recording medium according to claim 3, wherein the optical recording medium is set to 3 times. The optical recording medium according to claim 2, wherein the meandering amplitude of the third region is set to be the same as the meandering amplitude of the first region. The first region has a groove track depth of 30 nm, the second region has a pit depth of 80 nm, an average pit row duty of approximately 50%, and a meandering amplitude of the first region. Each of the third regions is set to approximately 2.7 times the meandering amplitude, the pit depth is 50 nm, the average duty of the pit row is about 80%, and the meandering amplitude is the same as the meandering amplitude of the first region. The optical recording medium according to claim 5, wherein each is set. In an optical recording medium manufacturing apparatus for manufacturing an optical recording medium capable of optically recording recording information using an optical disc master, while a groove track is meandered using a light beam modulated by a wobble signal having a constant frequency. Necessary for the reproduction control of the recorded information using the first area forming means for forming the first area where the recording information is recorded by cutting on the optical disc master and the light beam modulated by the wobble signal While the phase pit row corresponding to the control data is meandering to the optical disc master by a pit depth that enables reading of the control data and prevents reading of other data overwritten on the phase pit row. A second region forming means for cutting and forming a second region; and a light beam modulated by the wobble signal. The phase pit sequence corresponding to the predetermined data can be read out from the pre-pit including address information indicating the recording position on the optical recording medium, and other data overwritten and recorded on the phase pit sequence is recorded. A third region forming means for forming a third region by cutting while meandering the optical disc master with a pit depth that prevents reading, and forming the second region forming unit and the third region forming unit. In the means, the output level of the wobble signal extracted from the respective areas at the time of reproduction of the optical recording medium manufactured using the optical disc master is substantially the same as the output level of the wobble signal extracted from the first area. The optical recording medium manufacturing apparatus is characterized in that the degree of modulation of the light beam by the wobble signal is set. 8. The optical recording medium manufacturing apparatus according to claim 7, wherein the first region forming unit and the third region forming unit form the pre-pits. In an optical recording medium manufacturing method in which an optical recording medium capable of optically recording recording information is manufactured using an optical disc master, a groove track is meandered using a light beam modulated by a wobble signal having a constant frequency. Necessary for the reproduction control of the recording information by using the first area forming step for forming the first area where the recording information is recorded by cutting on the optical disc master and the light beam modulated by the wobble signal. While the phase pit row corresponding to the control data is meandering to the optical disc master by a pit depth that enables reading of the control data and prevents reading of other data overwritten on the phase pit row. A second region forming step of cutting and forming a second region; and a light beam modulated by the wobble signal The phase pit sequence corresponding to the predetermined data can be read out from the pre-pit including address information indicating the recording position on the optical recording medium, and other data overwritten and recorded on the phase pit sequence is recorded. A third region forming step of forming a third region by cutting while meandering the optical disc master with a pit depth that prevents reading, and forming the second region and the third region In the step, the output level of the wobble signal extracted from each of the areas when reproducing the optical recording medium manufactured using the optical disc master is substantially the same as the output level of the wobble signal extracted from the first area. The optical recording medium manufacturing method is characterized in that the degree of modulation of the light beam by the wobble signal is set. The optical recording medium manufacturing method according to claim 9, wherein the pre-pits are formed in the first region forming step and the third region forming step.

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