JP4272197B2 - DVD - Google Patents

Description

  The present invention belongs to the technical field of information recording media, and more particularly, to the technical field of information recording media capable of recording and reproducing optical information with so-called push-pull tracking servo control.

  In recent years, a so-called DVD having a recording capacity several times higher than that of a conventional CD (Compact Disc) has been widely used as an information recording medium capable of recording an image and sound for one movie.

  Recently, in addition to the reproduction-only DVD, which has been generalized, a DVD standard that can be recorded and reproduced multiple times and can be reproduced in an information reproduction apparatus for reproducing the reproduction-only DVD. As a result, a standard for so-called DVD-RW (DVD-Re-recordable) is being developed.

  Here, in the information recording medium that complies with the DVD-RW standard that is currently being formulated, the DVD-RW meanders at a constant frequency of about 0.3 micrometers in width and about 20 nanometers in depth. The groove track is formed as an information track on which optical information is recorded and reproduced. At this time, the reason why the groove track meanders is to generate a recording reference clock signal having an accurate frequency synchronized with the rotation of the DVD-RW by detecting the meandering frequency during information recording. .

  On the other hand, since the DVD-RW has basically the same recording capacity as a reproduction-only DVD, illegally copying images, etc. recorded on the reproduction-only DVD to the DVD-RW. Is also possible. At this time, an image or the like recorded on the reproduction-only DVD is usually protected by the copyright law, and therefore, if illegal copying as described above prevails, it is extremely disadvantageous for the copyright holder.

  Therefore, as a measure to prevent this illegal copying, in this standard, the area on the DVD-RW corresponding to the area where the control information for reproduction control is recorded in the reproduction-only DVD is made an unrecordable area. Therefore, it is trying to prevent the illegal copying.

  In addition, according to the standard, a reproduction-only area is provided on the unrecordable area, and predetermined reproduction control information and the like are allowed to be recorded in advance. In order to record the reproduction control information and the like, it is standardized to use so-called phase pits that are also used in a reproduction-only DVD.

  On the other hand, when optically recording and reproducing information on a DVD-RW using a light beam such as a laser beam, it is standardized to perform tracking servo control by a so-called push-pull method.

  However, if the tracking error signal is obtained by the push-pull method when reproducing the reproduction control information recorded by forming the phase pits in the reproduction-dedicated area described above, it is preliminarily formed in the reproduction-dedicated area. Pre-pits (that is, pre-pits formed in a land track formed adjacent to the above-described groove track and used for recording information on the groove track other than the read-only area (DVD- When the tracking error signal and the detection signal corresponding to the reproduction control signal cannot be obtained together with sufficient quality due to the influence of the interference with the pre-pit) for recording the address information indicating the recording position on the RW) There was a problem that there was.

  Therefore, the present invention has been made in view of the above-mentioned problems, and the problem is that the reproduction control information recorded therein is reproduced from the reproduction-only area formed on the DVD-RW. In some cases, an information recording medium capable of obtaining both a detection signal corresponding to the reproduction control information and a push-pull tracking error signal with sufficient quality is provided.

In order to solve the above problems, the invention described in claim 1 is to meander in a DVD (Digital Versatile Disc) in which recording information is optically recorded and reproduced while tracking servo control is performed by a push-pull method. However, a groove track formed continuously, and a groove track in which the recording information is recorded and reproduced by a phase change method using a light beam having a wavelength of 630 nanometers or more and 680 nanometers or less, and A recording / reproducing area having a land track, and a read-only area formed on the inner side of the recording / reproducing area in the information recording medium, wherein the area is 60 nm or more and 90 nm or less. a plurality of phase pits are previously formed by meandering, 630 nm or more 680 nano having a depth of Only the light beam information reproduction by having a wavelength of less Toru possible, and provided the land track, wherein the groove track and successive consecutive and read-only area is not formed together, a, Except the reproduction only area , at least the recording area, Ru said information recording is formed pre-pit indicating address information corresponding to the recording position on the medium is pre-Tei of the record information.

  Next, a preferred embodiment of the present invention will be described with reference to FIGS. The embodiment described below is an embodiment when the present invention is applied to a DVD-RW as an information recording medium, which is a DVD that can be rewritten a plurality of times, which has been standardized in recent years.

  FIG. 1 is a plan view of the DVD-RW according to the embodiment (plan view at the time of shipment from a manufacturing factory (hereinafter simply referred to as shipment)), and FIG. 2 is a DVD- on which pre-pits described later are formed. 3 is a cross-sectional view showing the structure of the RW, FIG. 3 is an enlarged plan view showing the structure of a read-only area and an impossible area, which will be described later, and FIG. 4 is a cross-sectional view showing the structure of the read-only area according to the present invention. FIG. 5 is a diagram showing a part of a recording format in DVD-RW, and FIG. 6 is a graph showing an experimental result corresponding to the present invention.

  As shown in FIG. 1, the DVD-RW 1 according to the embodiment, when shipped, records information on the DVD-RW 1 (information such as image information to be originally recorded on the DVD-RW 1 other than pre-information to be described later). A clamp hole CH used for fixing to a spindle motor (spindle motor for rotating the DVD-RW 1 at a preset rotation number) in an information recording apparatus (not shown) that records Further, only a reproduction-only area RA that can only reproduce information according to the present invention and an impossible area UA that cannot record and reproduce information are formed on a concentric circle.

  At this time, the reproduction-only area RA and the impossible area UA correspond to areas where control information for reproduction control is recorded on the reproduction-only DVD in order to prevent illegal copying with respect to the DVD-RW 1 as described above. The area on the DVD-RW 1 is an unrecordable area.

  In the information recording apparatus, after the initialization that is set in advance for recording information on the DVD-RW 1 is performed, the DVD-RW 1 includes the information as shown by the broken line in FIG. Control information used for recording and reproduction of recording information on the DVD-RW 1 from the circumferential side (specifically, setting information for setting the intensity of the light beam for recording and reproduction and recording control information used for the recording) Etc.), the control information area RI recorded by the initialization, the start information for starting the recording and reproduction, the lead-in area LI recorded by the initialization, and the information to be recorded on the DVD-RW1 Is formed (in FIG. 1, in FIG. 1, the read-only area RA and the impossible area already formed at the time of shipment are formed. In order to distinguish the UA from the control information area RI, the lead-in area LI, and the recording / reproduction area DA that are formed for the first time after the initialization, a section indicating the control information area RI, the lead-in area LI, and the recording / reproduction area DA The lines are broken lines.)

  At this time, after the initialization, both the reproduction-only area RA and the impossible area UA are included in the lead-in area LI.

  In addition, the lead-out area in which the end information indicating that the recording of the recording information on the DVD-RW 1 is finished is recorded on the outermost peripheral portion of the recording / reproducing area DA when the information recording on the entire DVD-RW 1 is finished. Will be formed.

  Next, the structure of the DVD-RW 1 in the recording / reproducing area DA will be described with reference to FIG. 2A is a perspective view showing the structure of the DVD-RW 1 in the recording / reproducing area DA, and FIG. 2B is a cross-sectional view of the groove track as viewed from the direction of the arrow in the perspective view.

  In the DVD-RW 1 according to the embodiment, in the area to be the lead-in area LI after the initialization in the information recording apparatus described above (excluding the reproduction-only area RA described later) and in the area to be the recording / reproduction area DA. At the time of shipment, address information indicating the recording position of information on the DVD-RW 1 is recorded as pre-information by forming a pre-pit 4 (generally referred to as a land pre-pit), which will be described later. ing.

  In addition, in the area to be the recording / reproducing area DA after the initialization, the entire recording operation for recording information on the DVD-RW1 (including the rotational speed control of the DVD-RW1) is similarly performed at the time of shipment. .) Is a reference to generate a recording clock signal used in the information recording apparatus to cause wobbling of the groove track 2 described later at the low frequency (that is, corresponding to the low frequency). Meandering at a period of time).

  Next, the structure will be specifically described.

  2 (a) and 2 (b), DVD-RW1 is a phase change type DVD-RW that is provided with a recording layer 11 made of a phase change thin film and is capable of writing information a plurality of times. A groove track 2 that is a power track, and a land track 3 for guiding a light beam B (having a wavelength of 650 nm) such as a laser beam as reproduction light or recording light to the groove track 2. Are formed on the substrate 9 adjacent to each other.

  Further, in each groove track 2, as shown in FIG. 2 (b) in particular, protective layers 5 and 8 having a function of protecting the recording layer 11 so as to sandwich the recording layer 11, and recorded recording information are recorded. A reflective layer 6 for reflecting the light beam B during reproduction, a recording layer 11, protective layers 5 and 8, and a resin layer 9A and a protective film 7 for further protecting the reflective layer 6 from the outside air, etc., are respectively substrates. 9 are stacked on top of each other.

  At this time, it is standardized that the depth of the groove track 2 is 20 nm or more and 35 nm or less at the position of the recording layer 11. The distance between the center lines of adjacent groove tracks 2 is 0.74 micrometers.

  On the other hand, pre-pits 4 corresponding to the pre-information are formed on the land track 3 at the time of shipment.

  Further, in the DVD-RW 1, the groove track 2 is wobbled so as to correspond to the low frequency (specifically, 140 kilohertz) signal used for generating the recording clock signal as described above.

  When recording information on the DVD-RW 1, the information recording apparatus detects the low frequency signal in the wobbling of the groove track 2, thereby acquiring the recording clock signal and recording operation of the DVD-RW 1. Control overall. In parallel with this, pre-information is acquired in advance by detecting the pre-pit 4 in the information recording apparatus, and the optimum output of the optical beam B as recording light is set based on the pre-information, and further the address Information or the like is acquired, and recording information is recorded at a corresponding recording position based on the address information.

  Here, as shown in FIG. 2A, when recording information is recorded, the light beam B is irradiated so that the center thereof coincides with the center of the groove track 2, and the phase corresponding to the recording information is recorded on the groove track 2. Recording information is formed by forming a change pit.

  At this time, the size of the light spot SP is set so that a part of the light spot SP is irradiated not only on the groove track 2 but also on the land track 3 as shown in FIG. Then, a push-pull method (radial push-pull using a photodetector divided by a dividing line parallel to the rotation direction of the DVD-RW 1) using a part of the reflected light of the light spot SP irradiated to the land track 3 is used. The pre-information is detected from the pre-pit 4 by the system), and the pre-information is acquired, and the multi-frequency signal is detected from the groove track 2 using the reflected light of the light spot SP irradiated on the groove track 2. Generation of a recording clock signal or acquisition of address information is executed.

  Further, the light beam B is applied to the groove track 2 accurately in the manner shown in FIG. 1A by following the position change of the groove track 2 (position change in the radial direction accompanying the rotation of the DVD-RW 1). It is standardized that so-called tracking servo control is also performed by the push-pull method described above.

  Next, the structure of the DVD-RW 1 in the read-only area RA will be described with reference to FIGS. FIG. 3 is an enlarged plan view showing the structure near the boundary between the read-only area RA and the impossible area UA in the DVD-RW 1, and FIG. 4A shows a phase pit described later in the read-only area RA. FIG. 4B is a cross-sectional view of the portion (AA ′ portion in FIG. 3) seen from the same direction as FIG. 2B, and FIG. 4B shows that the phase pit is not formed in the read-only area RA. It is sectional drawing seen from the direction similar to FIG.2 (b) of a part (BB 'part in FIG. 3).

  In the read-only area RA described above, the continuous groove track 2 and land track 3 as shown in FIG. 2 are not formed. In the reproduction-only area RA, reproduction control information used when reproducing recorded information from the DVD-RW 1 is intermittently wobbled at the same period as the groove track 2 as shown in FIG. (The wobbling state is indicated by the center line CL in FIG. 3.) The formed phase pit (that is, the same phase pit as that formed on a reproduction-only DVD, and the phase pit is formed) The light beam B irradiated to a certain area is diffracted by the phase pit, and is recorded by a phase pit (PI) for determining the presence or absence of the phase pit and detecting reproduction control information or the like.

  At this time, the depth of the phase pit PI in the read-only area RA is set to 60 nm or more and 90 nm or less (desirably 70 nm or more and 80 nm or less) at the position of the recording layer 11. Further, the interval between the center lines of the phase pits PI adjacent to each other in the radial direction of the DVD-RW 1 is set to 0.74 μm as in the case of the groove track 2.

  On the other hand, the read-only area RA in which the phase pit PI is not formed is a completely flat surface as shown in FIG.

  Further, the pre-pit 4 is not formed in the reproduction-only area RA. This is because if the phase pit PI and the pre-pit 4 are formed in the same region, they interfere with each other optically and cannot be detected.

  Next, the structure of the DVD-RW 1 in the impossible area UA 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.

  In the impossible area UA, phase pits PI 'are wobbled and irregularly formed.

  At this time, the depth of the phase pit PI ′ is set to 20 nm or more and 35 nm or less at the position of the recording layer 11 (that is, the same depth as that of the groove track 2). Even if phase change pits are formed on the recording layer 11 in the possible area UA by the light beam B, the contents cannot be detected due to interference with the phase pits PI ′ located above the phase change pits.

  In the impossible area UA, address information is recorded by the prepit 4. Therefore, at the time of recording the recording information, 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 / reproducing area DA along with the rotation of the DVD-RW 1. .

  Note that the phase pits PI and PI 'described above may be generally referred to as embossed prepits.

  Next, the recording format of the DVD-RW1 after the lead-in area LI and the recording / reproducing area DA are formed on the DVD-RW1 will be described with reference to FIG.

  As shown in FIG. 5, after the initialization, in the lead-in area LI, the initial zone IZ in which all zero data (“00h”) is recorded from the inner periphery side, the start information, etc. A reference code zone RZ in which a reference code including "Z" is recorded, a first buffer zone B1 in which all zero data is recorded, the above-described reproduction-only area RA and impossible area UA, and all zero data are recorded. The second buffer zone B2 is formed.

  Of these, the pre-pit 4 is formed in the lead-in area LI except for the read-only area RA. The address information indicated by the pre-pit 4 is the initial zone IZ as shown on the left of FIG. The reference code zone RZ and the first buffer zone B1 are set so as to be sequentially incremented (digitally increased) from the inner peripheral side, while the impossible area UA and the second buffer zone B2 are recorded / reproduced areas. It is set so as to decrement (decrease digitally) sequentially from the innermost circumference of DA (that is, the outermost circumference of the second buffer zone B2). Accordingly, the address information is discontinuous in the innermost and outermost peripheral portions of the read-only area RA.

  On the other hand, as to the so-called sector number in the recording information corresponding to the address information, as shown in the right of FIG. 5, the reproduction-only area RA is recorded in advance by the phase pit PI at the time of shipment. In the lead-in area LI excluding the impossible area UA, after initialization, the read-only area RA is set so as to be continuous including the sector number recorded therein. At this time, the impossible area UA is set so as to continuously change between the innermost periphery and the outermost periphery.

  Next, in the embodiment, the depth of the phase pit PI in the read-only area RA is set to be 60 nm or more and 90 nm or less (desirably 70 nm or more and 80 nm or less) deeper than the groove track 2. This will be described with reference to FIG.

  FIG. 6 shows an output level of a detection signal (detection signal corresponding to the sector number recorded by the phase pit PI) detected from the read-only area RA and tracking for push-pull tracking servo control. It is a graph (experimental result) which shows the relationship between the output level of an error signal, and the depth of phase pit PI. In addition, the experimental result shown in FIG. 6 is an experimental result when the wavelength of the light beam B is 630 nanometers or more and 680 nanometers or less.

  As described above, in order to accurately detect the tracking servo control in the read-only area RA and detect sector information or the like recorded in advance in the read-only area RA, both the detection signal and the tracking error signal described above are used. Although it is necessary to detect at a good output level, as shown in FIG. 6, if the depth of the phase pit PI is 60 nm or more and 90 nm or less (B region in FIG. 6), both signals are detected. It can be seen that detection can be performed with an allowable output level. If the depth is in the range of 70 nanometers or more and 80 nanometers or less (A region in FIG. 6), both signals can be detected best.

  Therefore, the phase pit PI of the embodiment has a depth of 60 to 90 nanometers (desirably 70 to 80 nanometers).

  As described above, according to the DVD-RW 1 of the embodiment, the phase pit PI formed in the read-only area RA has a depth of 60 nanometers or more and 90 nanometers or less. In the region RA, the detection signal and the tracking error signal can be acquired at a sufficient output level by the light beam B having a wavelength range of 630 nm or more and 680 nm or less.

  Further, when the depth of the phase pit PI formed in the read-only area RA is 70 nm or more and 80 nm or less, both the detection signal and the tracking error signal are acquired at a higher output level. Can do.

  Further, since the prepit 4 is formed at least in the recording / reproduction area DA excluding the reproduction-only area RA, it is possible to prevent the prepit 4 from obstructing the acquisition of the detection signal and the tracking error signal from the reproduction-only area RA. .

  Furthermore, since the impossible area UA is formed between the reproduction-only area RA and the recording / reproduction area DA, illegal copying and illegal reproduction with respect to the DVD-RW 1 is performed due to the existence of the reproduction-only area RA and the impossible area UA. It can be surely prevented.

  Further, the prepit 4 is formed in the impossible area UA, and the address information indicated by the prepit 4 in the impossible area UA is calculated backward from the address information corresponding to the innermost peripheral portion of the recording / reproducing area DA. Since it is set, information can be recorded in the recording / reproducing area DA while accurately grasping the recording position without being affected by the existence of the reproduction-only area RA.

  As described above, the information recording medium DVD-RW1 of the above embodiment meanders in the information recording medium DVD-RW1 in which information is optically recorded and reproduced while servo control is performed by the push-pull method. Recording / reproduction having a groove track 2 which is continuously formed and information is recorded and reproduced by a phase change method using a light beam B having a wavelength of 630 to 680 nm. A region DA and a reproduction-only region RA in which a plurality of phase pits PI having a depth of 60 to 90 nanometers meander and are formed in advance, and only information reproduction by the light beam B is possible. The recording position of information on the information recording medium DVD-RW1 is at least in the recording / reproducing area DA excluding the reproduction-only area RA. Pre-pit 4 is formed that indicates that the address information corresponds to.

  According to this, since the phase pit PI formed in the read-only area RA on the information recording medium DVD-RW1 has a depth of 60 nanometers or more and 90 nanometers or less, Both the detection signal corresponding to the information to be reproduced at a sufficient output level and the error signal for push-pull servo control can be acquired by the recording / reproducing light beam B having the above wavelength range.

  Therefore, by providing the reproduction-only area RA that can only be reproduced, illegal copying with respect to the information recording medium DVD-RW1 and illegal reproduction of the illegally copied information can be prevented, and the reproduction-only area RA can be prevented. Necessary information such as copy control information can be recorded in advance using the phase pit PI and can be reproduced well.

  In addition, since the prepit 4 indicating the address information is formed at least in the recording / reproducing area DA excluding the reproduction-only area RA in the information recording medium DVD-RW1, the detection signal and error signal from the reproduction-only area RA are formed by the prepit 4. Can be prevented from being obstructed.

  In the information recording medium DVD-RW1 of the above embodiment, the depth of the phase pit PI is 70 nanometers or more and 80 nanometers or less.

  According to this, since the depth of the phase pit PI formed in the read-only area RA is 70 nanometers or more and 80 nanometers or less, the detection signal and the error signal are obtained at a higher output level. can do.

  The information recording medium DVD-RW1 of the above embodiment has a plurality of phase pits PI that are meandering in advance and an impossible area UA in which information cannot be recorded and reproduced by the light beam B is a reproduction-only area. It is further formed in an area on the information recording medium DVD-RW1 between the RA and the recording / reproducing area DA.

  According to this, since the impossible area UA is formed between the reproduction-only area RA and the recording / reproducing area DA, the information recording medium DVD-RW1 is caused by the existence of the reproduction-only area RA and the impossible area UA. Unauthorized copying and unauthorized reproduction can be surely prevented.

  In the information recording medium DVD-RW1 of the above embodiment, the prepit 4 is formed in the impossible area UA, and the address information indicated by the prepit 4 in the impossible area UA is in the information recording medium DVD-RW1. Is set based on address information corresponding to the head of the recording / reproduction area DA.

  According to this, the prepit 4 is further formed in the impossible area UA, and the address information indicated by the prepit 4 in the impossible area UA is based on the address information corresponding to the head of the recording / reproducing area DA. Therefore, it is possible to record information in the recording / reproducing area DA while accurately grasping the recording position without being affected by the existence of the reproduction-only area RA.

It is a top view of DVD-RW which concerns on embodiment. It is a figure which shows the structure of DVD-RW in which the prepit is formed, (a) is a perspective view which shows the said structure, (b) is the sectional drawing. It is a plane enlarged view which shows the structure of the read-only area | region and impossible area which concern on embodiment. It is sectional drawing which shows the structure of the read-only area | region which concerns on embodiment, (a) is sectional drawing of the part in which the phase pit is formed, (b) is a step surface figure of the part in which the phase pit is not formed It is. It is a figure which shows a part of recording format in DVD-RW. It is a graph which shows the experimental result corresponding to embodiment.

Explanation of symbols

1 ... DVD-RW
2 ... Groove track 3 ... Land track 4 ... Pre-pit 5, 8 ... Protective layer 6 ... Reflective layer 7 ... Protective film 9 ... Substrate 9A ... Resin layer 11 ... Recording layer CH ... Clamp hole RA ... Read-only area UA ... Impossible area RI ... Control information area LI ... Lead-in area DA ... Recording / reproduction area B ... 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 (4)

In DVD (Digital Versatile Disc) in which recording information is optically recorded and reproduced while tracking servo control is performed by the push-pull method,
A groove track which is continuously formed while meandering, wherein the recording information is recorded and reproduced by a phase change method using a light beam having a wavelength of 630 nanometers or more and 680 nanometers or less ; A recording / reproducing area having a land track formed continuously ;
In the information recording medium, the read-only area is formed on the inner circumference side of the recording / reproducing area, and a plurality of phase pits having a depth of 60 nanometers or more and 90 nanometers or less are meandered in advance. A read-only area in which only the information reproduction by the light beam having a wavelength of 630 nanometers or more and 680 nanometers or less is possible , and the continuous groove track and the continuous land track are not formed together ,
With
The read-only area-out removal, at least in the recording area, DVD prepit indicating the address information corresponding to the recording position on the information recording medium of the record information is characterized Tei Rukoto preformed. The DVD of claim 1,
The DVD, wherein the phase pit has a depth of 70 nanometers or more and 80 nanometers or less. The DVD according to claim 1 or 2,
A plurality of phase pits that are shallower than the phase pits formed in the read-only area meander in advance as phase pits that carry the address information, so that information using the light beam An impossible area where recording and reproduction are both impossible, and an impossible area where the continuous groove track and the continuous land track are not formed together are the reproduction-only area and the recording / reproduction area. The DVD is further formed in an area on the information recording medium between the two. The DVD according to claim 3,
The prepits are formed in the impossible area,
The DVD according to claim 1, wherein the address information indicated by the pre-pits in the impossible area is set based on the address information corresponding to a head of the recording / reproducing area in the information recording medium.

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