JP3477168B6 - Optical disc having rewritable area and read-only area - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disc having a recordable or reproducible area (hereinafter referred to as a rewritable area) and a reproducible area (hereinafter referred to as a reproduction-only area).
[0002]
[Prior art]
When the rewritable area and the reproduction-only area are mixed on the optical disc, how to set the boundary between the rewritable area and the reproduction-only area becomes a problem.
[0003]
[Problems to be solved by the invention]
When the two areas are too close at the boundary between the rewritable area and the read-only area, data confusion occurs. On the other hand, if the two areas are separated from each other, the use efficiency of the optical disk is reduced.
[0004]
The present invention solves the above problem, determines the arrangement condition at the boundary between the rewritable area and the reproduction-only area, prevents the data in both areas from being confused, and makes both areas substantially adjacent to each other, or An object of the present invention is to provide a new optical disk that is arranged through lands having a certain width and does not cause a decrease in the utilization efficiency of the optical disk.
[0005]
[Means for Solving the Problems]
The invention for achieving the above object is as follows.
[0006]
The optical disk of the present invention has a rewritable area having a recording track formed in a spiral shape having a pitch Pa, in which lands and grooves are alternately connected on a switching line assumed on a predetermined radius, and a pitch Pb. A read-only area in which information is recorded in advance by a continuous mark row on a recording track formed in a spiral shape, and switching between the rewritable area and the read-only area is substantially on the radius. The optical disk is characterized in that it is performed along the switching line assumed in the above, and the above object is achieved.
[0007]
In the above-described optical disc, the rewritable area has a plurality of recording sectors, and each recording sector has a header area pre-formatted with marks representing address information and a data recording area for recording data. , The header area is 2K physical address areas PID (K is a positive integer)_iEach physical address area PID_iIncludes at least an address area Pid for storing sector address information and a physical address area PID₁.. PID_kIs offset from the groove recording track by about Pa / 2 in the first radial direction of the disk, and the physical address area PID_{k + 1}.. PID_2kMay be offset from the groove recording track by about Pa / 2 in the second radial direction of the disc.
[0008]
In the above-described optical disc, Pa and Pb may be substantially equal.
[0009]
The invention described in this specification is at least as follows. Both a groove and a land between the grooves are formed on the disk substrate in a circular shape, and a recording track of the groove corresponding to one round of the disk and a recording track of the land corresponding to one round of the disk are predetermined. A recording spiral is formed by being alternately connected on the switching line assumed on the radius, and the track pitch Pa of the recording track is set to a value smaller than λ / NA, and a lens having a predetermined numerical aperture NA. Including a phase change recording film in which a local reflectance change is generated by irradiating a laser beam with a predetermined wavelength λ collected by the laser beam, and information is obtained by the edge positions at the front and rear ends of the recording mark generated by the local reflectance change. A rewritable area in which a first information data recording area where recording is performed is arranged and an uneven pit row is formed and arranged in advance on the optical disc. Thus, a spiral recording track having a track pitch Pb substantially equal to the track pitch Pa of the recording track is formed, and a read-only area having a second information data recording area in which information data is recorded in advance is provided. The rewritable area has a plurality of recording sectors, and each recording sector has a first header area pre-formatted with embossed pits representing address information, and first information data for recording data The first header area includes at least a physical address area PID including an address area Pid for storing sector address information, and the physical address area PID is 2K times (K is a positive integer). Repeatedly, 2K physical address area PID is next PID₁... PID_{K ,}PID_{K + 1}... PID_2KWhen expressed in the first half PID₁... PID_{K ,}Is about Pa / 2 away from the groove recording sector track in the first radial direction of the disk, and the latter half PID_{K + 1}... PID_2K, Is a deviation of about Pa / 2 from the track of the groove recording sector in the second radial direction of the disk, and the rewritable area has a start track land composed of a spiral pattern of one round at the head end, and an end. The end of the physical address area PID that is deviated from the track of the rewritable area by about Pa / 2 is formed between the start track land and the end track land. It is an optical disc characterized by entering inside.
[0010]
According to the first aspect of the present invention, in the optical disk, the boundary between the rewritable area and the read-only area always has the start track land or the end track land existing in contact with the boundary line above the rewritable area. The surface level of the land is the same as the level of the read-only area of the boundary line. As a result, the boundary line between the rewritable area and the read-only area never touches the groove. The record mark of the rewritable area groove is not mistakenly mixed with the embossed mark of the read-only area.
[0011]
The portion of the physical address area PID having a deviation of about Pa / 2 from the track in the rewritable area has entered the start track land or the end track land. As a result, the part with the deviation does not enter the reproduction-only area. Accordingly, no crosstalk occurs between the data in the physical address area PID and the embossed mark in the reproduction-only area.
[0012]
The second invention is the optical disk of the first invention, and further includes an additional land located between the start track land and the adjacent read-only area and having a predetermined width, and is terminated. The optical disk includes another additional land located between the track land and the adjacent read-only area and having a predetermined width.
[0013]
According to the second invention, it is possible to prevent crosstalk between the rewritable area and the reproduction-only area by inserting an additional land. Further, since an additional land is provided, it is not necessary to adjust the arrangement between the tracks in the rewritable area and the reproduction-only area. Further, by detecting the additional land, it is possible to distinguish between the rewritable area and the reproduction-only area.
[0014]
A third invention is an optical disk according to the first invention, wherein the rewritable area and the reproduction-only area are formed at least in a lead-in area on the center side of the optical disk, and the reproduction-only area is controlled in advance. The optical disk is used as a control data zone in which data is written.
[0015]
According to the third aspect of the invention, the rewritable area and the reproduction-only area are provided in the lead-in area in the central portion of the optical disc. As a result, it is possible to add control data to the reproduction-only area used as the control data zone so that no data is written to the start track and the end track.
[0016]
4th invention is an optical disk based on the said 3rd invention, Comprising: The data which prohibits recording data on the said start track land and the end track land are contained in the said control data It is.
[0017]
According to the fourth aspect of the invention, data read from the read-only area is not confused with data read from the rewritable area. The reason is that no data is described in the start track or the end track land.
[0018]
A fifth invention is an optical disk according to the first invention, characterized in that switching between the read-only area and the rewritable area is performed substantially along a switching line.
[0019]
According to the fifth aspect, the leading ends of the tracks in the reproduction-only area and the rewritable area are arranged along the switching line. As a result, it is possible to easily seek the track and control the track. In addition, it is easy to find where the switching between the reproduction-only area and the rewritable area is.
[0020]
A sixth invention is an optical disk based on the first invention, wherein the wavelength λ of the laser beam is 650 nm, the lens numerical aperture NA is 0.6, and both the track pitch Pa and the track pitch Pb are 0.74 μm. The optical disc employs a modulation system that modulates 8 information bits into 16 channel bits, has a shortest recording mark length of 3 channel bits, and a longest recording mark length of 11 channel bits.
[0021]
According to the sixth aspect of the invention, it is possible to efficiently and compactly create a data format without wasting disk space.
[0022]
The optical disk of the seventh invention has the following configuration.
[0023]
Both a groove and a land between the grooves are formed on the disk substrate in a circular shape, and a recording track of the groove corresponding to one round of the disk and a recording track of the land corresponding to one round of the disk are predetermined. A recording spiral is formed by being alternately connected on the switching line assumed on the radius, and the track pitch Pa of the recording track is set to a value smaller than λ / NA, and a lens having a predetermined numerical aperture NA. Including a phase change recording film in which a local reflectance change is generated by irradiating a laser beam with a predetermined wavelength λ collected by the laser beam, and information is obtained by the edge positions at the front and rear ends of the recording mark generated by the local reflectance change. A rewritable area in which a first information data recording area where recording is performed is arranged and an uneven pit row is formed and arranged in advance on the optical disc. Thus, a spiral recording track having a track pitch Pb substantially equal to the track pitch Pa of the recording track is formed, and a read-only area having a second information data recording area in which information data is recorded in advance is provided. The rewritable area has a plurality of recording sectors, and each recording sector has a first header area pre-formatted with embossed pits representing address information, and first information data for recording data The first header area includes at least a physical address area PID including an address area Pid for storing sector address information, and the physical address area PID is 2K times (K is a positive integer). Repeatedly, 2K physical address area PID is next PID₁... PID_{K ,}PID_{K + 1}... PID_2KWhen expressed in the first half PID₁... PID_{K ,}Is about Pa / 2 away from the groove recording sector track in the first radial direction of the disk, and the latter half PID_{K + 1}... PID_2K, But a deviation of about Pa / 2 from the track of the groove recording sector is in the second radial direction of the disk, and the rewritable area is connected to the read-only area via a land having a width substantially equal to a plurality of track widths. It is an optical disc characterized by being located close to each other.
[0024]
The optical disk of the eighth invention has the following configuration.
[0025]
Both a groove and a land between the grooves are formed on the disk substrate in a circular shape, and a recording track of the groove corresponding to one round of the disk and a recording track of the land corresponding to one round of the disk are predetermined. A recording spiral is formed by being alternately connected on the switching line assumed on the radius, and the track pitch Pa of the recording track is set to a value smaller than λ / NA, and a lens having a predetermined numerical aperture NA. Including a phase change recording film in which a local reflectance change is generated by irradiating a laser beam with a predetermined wavelength λ collected by the laser beam, and information is obtained by the edge positions at the front and rear ends of the recording mark generated by the local reflectance change. A rewritable area in which a first information data recording area where recording is performed is arranged and an uneven pit row is formed and arranged in advance on the optical disc. Thus, a spiral recording track having a track pitch Pb substantially equal to the track pitch Pa of the recording track is formed, and a read-only area having a second information data recording area in which information data is recorded in advance is provided. The optical disk is characterized in that switching between the rewritable area and the reproduction-only area is substantially along a switching line.
[0026]
A ninth invention is an optical disk according to the eighth invention, characterized in that the groove pitch of the rewritable area is twice the pitch of the embossed mark of the reproduction-only area.
[0027]
According to the ninth aspect, data can be recorded in the rewritable area at the same density as the recording density used in the reproduction-only area.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The present invention can be more fully understood from the following detailed description and the accompanying drawings.
[0029]
(First Embodiment) An embodiment of the present invention will be described below with reference to the drawings.
[0030]
FIG. 1 shows a plan view of an optical disc 1 according to the present invention. The optical disk 1 is composed of a rewritable area (recordable or reproducible area) 2, a reproduction-only area (reproduction-only area) 3, a rewritable area 4, a reproduction-only area 6, and a rewritable area 7. .
[0031]
The inner areas 2, 3, and 4 constitute a lead-in area 5, the rewritable areas 2 and 4 are areas for inspecting the recording characteristics of the optical disc, and the read-only area 3 is the characteristics and format of the optical disc 1. Is an area recorded in advance.
[0032]
The read-only area 6 and the rewritable area 7 outside the lead-in area 5 constitute a data area 8 where audio data and video data are recorded.
[0033]
The arrangement of the rewritable area and the reproduction-only area provided on the optical disc 1 shown in FIG. 1 is merely an example. The optical disk 1 is provided with a spiral track from the inside to the outside, and data is recorded and reproduced along the track in the rewritable area, while data is reproduced along the track in the read-only area. The In the preferred embodiment, the track pitch is 0.74 μm.
[0034]
FIG. 2 is a diagram showing details of the rewritable area 2 and the reproduction-only area 3 formed on the substrate 10 having the refractive index n and the boundary portion thereof. The rewritable area 2 is composed of lands 11 that exist at the same level as the reference surface of the disk and extend along the track, and grooves 12 that are recessed from the reference surface by a predetermined amount Dp and extend along the track. In a preferred embodiment, the predetermined amount Dp is 0.07 μm. Further, the pitch Pa between the land 11 and the groove 12 adjacent thereto, that is, the distance between the center line of the land 11 and the center line of the groove 12 is 0.74 μm. Accordingly, the pitch of the land 11 itself (or the groove 12 itself) is twice the track pitch, that is, 1.48 μm.
[0035]
The surface of the land 11 or the groove 12 is provided with a phase change recording film 16, which is emitted locally from a laser beam emitted from a light source 17 and sent from a lens 18 having a predetermined numerical aperture NA. The irradiated portion undergoes a physical change, for example, a local change in reflectance, and binarized recording becomes possible. This irradiated portion is indicated by a recording mark 13. The recorded mark can be rewritten by irradiating the laser beam with the adjusted intensity again.
[0036]
In the preferred embodiment of the present invention, the wavelength λ of the laser beam is 650 nm, and the numerical aperture NA of the lens 18 is 0.6. The refractive index n of the optical disk substrate 10 is about 1.5. Note that the pitch Pa is smaller than λ / NA.
[0037]
In the track in the rewritable area, lands and grooves are alternately arranged in this way. This is to enable tracking of the laser beam.
[0038]
In FIG. 2, the read-only area 3 has a plurality of embossed marks 15, such as pits, arranged along a track on a land surface 14 that is at the same level as the reference surface of the disc. Since the embossed mark 15 is formed in advance, the user of the optical disk cannot erase or rewrite the embossed mark 15. The pitch Pb of the embossed marks 15 arranged adjacent to each other is 0.74 μm.
[0039]
The last track (referred to as the end track) adjacent to the reproduction-only area 3 in the rewritable area 2 is always composed of lands 11 as shown in FIG. 2, and such lands are handled as end track lands 11a. The land 11a which is the end track is configured to prohibit recording of any data. This prohibition is recorded in advance in accordance with the disk version protocol described above. The disc version is recorded in the read-only area 3 of the lead-in area 5. As shown in FIG. 4, the first track (referred to as the start track 11s) in the rewritable area 2 adjacent to the read-only area 3 is also formed of lands, and all recording is prohibited as with the end track. The
[0040]
In other words, in the rewritable area of the optical disk according to the present invention, grooves and lands are alternately arranged on the circumference of the disk, and the rewritable track always starts with a groove and ends with a groove. Furthermore, the first track land 11s is outside the rewritable groove at the beginning of the rewritable area, that is, on the inner peripheral side. The track land 11a at the end is outside the rewritable groove at the end of the rewritable area, that is, at the outer peripheral side. Data recording is prohibited in the first track land 11s and the last track land 11a. The first track land 11s and the end track land 11a are the first header first half 24 and the next half track whose width is deviated from the groove track of the read-only area adjacent to the first track land 11s and the end track land 11a. The header first half 25 is stored.
[0041]
FIG. 3 is an enlarged plan view of the rewritable area 2 and the reproduction-only area 3 as viewed from above, and one spiral track extends from the inside to the outside. In the rewritable area 2, the lands 11 and the grooves 12 are alternately arranged as described above. More specifically, the land 11 exists once around the predetermined switching line 26 and returns to the switching line 26 again. Subsequently, the groove 12 exists similarly. Moreover, the land 11 exists once. This switching line 26 is a virtual line extending in the radial direction from the center of the optical disc 1, and the land 11 and the groove 12 are switched on this line. Further, switching between the land 11 as the end track and the next reproduction-only area 3 is also performed on the switching line 26. That is, the switching point between the rewritable area and the reproduction-only area is always performed on the switching line 26. Further, as described above, the series of emboss marks 15 is formed on the spiral track of the reproduction-only area 3.
[0042]
The leading ends of the tracks in the rewritable area and the reproduction-only area are arranged along the switching line 26. As a result, it becomes easy to find the track and manage the track. Further, the location of the switching line 26 between the rewritable area and the reproduction-only area can be easily found.
[0043]
FIG. 4 shows an enlarged plan view of the rewritable area 2, the reproduction-only area 3, and the rewritable area 4 in the vicinity of the switching line 26. The track is divided into N sectors (N is a positive integer, for example, 17) 23 with a switching line 26 at the head. In the rewritable area 2, each sector 23 has a header area 21 at its head side and an information data recording area 22 that follows it through a mirror area. As will be described later, the read-only area 3 also has a header area 31 and an information data recording area 32. In particular, the header area 21 and the information data recording area 22 in the rewritable area 2 are designated as the first header area, the first data area, and the first data area. While referred to as an information data recording area, the header area 31 and the information data recording area 32 in the reproduction-only area 3 are referred to as a second header area and a second information data recording area.
[0044]
Further, the first header area 21 is divided into two parts, a header first half 24 and a header second half 25. The header first half portion 24 is located approximately one track half pitch from the center line of the groove 12 at a position shifted by 0.37 μm in the above example, while the header second half portion 25 is approximately spaced from the center line of the groove 12 to the other side. In the above example, it exists at a position shifted by 0.37 μm by the track half pitch. Details of the first header area 21 will be further described.
[0045]
As shown in FIG. 5, the header first half 24 is composed of a first area PID1 and a second area PID2 arranged continuously, and the header latter half 25 is a third area PID3 and a fourth area arranged successively. It consists of PID4. In each of the first to fourth areas, first to fourth identification codes are recorded, and sector addresses are also recorded. The address in this embodiment is modulated by a modulation method with a limited run length.
[0046]
FIG. 6 shows a specific data structure of the first header area 21 in the rewritable area. First, the signal format of the first header area 21 will be described. The first area PID1 includes a single frequency pattern area VFO1 for obtaining synchronous clock generation and detection timing during reproduction, an address mark area AM for recognizing the start of byte synchronization and detection timing during header reproduction, It comprises an address area Pid1 that holds sector address information, an address error detection area IED1 that holds a code for detecting an error in the address area, and a postamble area PA for completing modulation.
[0047]
Similarly, the second area PID2 is composed of a single frequency pattern area VFO2, an address mark area AM, an address area Pid2, an address error detection area IED2, and a postamble area PA.
[0048]
Similarly, the third area PID3 includes a single frequency pattern area VFO1, an address mark area AM, an address area Pid3, an address error detection area IED3, and a postamble area PA.
[0049]
Further, the fourth area PID4 includes a single frequency pattern area VFO2, an address mark area AM, an address area Pid4, an address error detection area IED4, and a postamble area PA.
[0050]
The modulation method is a method in which 8 information bits are modulated at a ratio of 16 channel bits, the channel bit with the shortest recording mark length is 3 bits, and the channel bit with the longest recording mark length is 11 bits.
[0051]
Each of the single frequency pattern areas VFO1 is an area where a specific pattern, for example, (00010001) repetitive patterns are recorded, and an oscillation circuit (PLL circuit shown in FIG. 8) in the reproduction circuit within the period of VFO1. Used for sync pull-in of the recovered clock generated from The length of the area VFO1 is set to a length that can include the edges of a sufficient number of recording marks for synchronization pull-in, and is preferably 36 bytes in the present invention.
[0052]
In addition, the same specific pattern is repeatedly recorded in each of the single frequency pattern areas VFO2, and the VFO2 has a length that can include the edges of a sufficient number of recording marks for re-synchronization of the reproduction clock. In this case, it is preferably 8 bytes.
[0053]
Each of the address mark areas AM has a length that can include a channel bit pattern having a recording mark length that does not appear in the modulation bit string, and is longer than the longest recording mark length of the modulation method. In this embodiment, 3 bytes are preferred.
[0054]
Each of the address areas Pid1, Pid2, Pid3, and Pid4 is an address for identifying a recording sector, and is preferably 4 bytes in the present invention.
[0055]
Each of the address error detection areas IED1, IED2, IED3, and IED4 has a length capable of detecting a reproduction error in the address area Pid with a known maximum error rate, and is preferably 2 bytes in the present invention.
[0056]
The postamble PA area has a length longer than that required by the modulation method and a length that can terminate the recording mark. In the present invention, the postamble area PA is preferably 1 byte.
[0057]
Further, as shown in FIG. 6, a mirror area 121 follows the first header area 21. The mirror region 121 is present on a flat surface where no groove or emboss mark is formed, and corrects, for example, tracking deviation. The detailed format of the first information data recording area 22 following the mirror area 121 will be described below.
[0058]
The first information data recording area 22 includes a gap area 122, a first guard data area, a single frequency pattern (VFO3) area 124, a pre-synchronization area, a data area 125, a postamble area, a guard data area 126, A buffer area 128 is included. The gap area 122, the first guard data area, the single frequency pattern (VFO3) area 124, and the pre-synchronization area are collectively referred to as the first buffer area, while the second guard data area 126 and the buffer Regions 128 together form a second buffer region.
[0059]
The gap region 122 is a region to which no signal is assigned, and is provided for adjusting the laser power.
[0060]
The first and second guard data area numbers 126 are arranged at the start and end portions of the recording data in order to compensate for the deterioration of the recording medium when repeated recording / playback is performed.
[0061]
In addition, the recording medium has a property that the deterioration progresses if the same data is repeatedly recorded in the same place. In order to compensate for this, the length of the guard data area before and after the data area is adjusted to move the recording position of the data area. By adjusting the length of the guard data area, the total length of the first guard data area and the second guard data area is constant.
[0062]
The single frequency pattern (VFO3) region 124 has a specific pattern, for example, a specific pulse width having a modulation code, in order to set the oscillation frequency of the oscillation circuit (in the PLL 152 of FIG. 8) in the reproduction circuit. This is an area for recording a repeated pattern.
[0063]
The presync area is a synchronization signal for detecting the head of the data area, and records a code pattern having a large autocorrelation.
[0064]
The data area 125 includes an error correction code and the like, and is an area for recording data that the user wants to store. This data can be erased and rewritten.
[0065]
The postamble area has a length longer than that required by the modulation method and a length that can terminate the recording mark. In the present invention, the postamble area is preferably 1 byte.
[0066]
The buffer area 128 is an area where nothing is recorded, and is provided to absorb a timing shift that occurs as a result of the rotational jitter of the optical disc 1. Therefore, the end 123b of the recording data can be prevented from overlapping the next header area.
[0067]
In the preferred embodiment of the present invention, the mirror area 121 is 2 bytes, the gap area 122 is 10 bytes, the single frequency pattern (VFO3) area 124 is 35 bytes, the pre-synchronization area is 3 bytes, and the data area 125 is 2418. The byte and postamble area is set to 1 byte, and the buffer area 128 is set to 40 bytes. The first guard data area is 19 ± 4 bytes, the second guard data area is 41 ± 4 bytes, and the total length of both guard data areas is constant at 60 bytes.
[0068]
In this embodiment, it should be noted that the length of the first and second guard data areas is expanded and contracted to move the position of the data area. However, the present invention is not limited to this. For example, the same effect can be obtained even when the lengths of the gap region and the buffer region are similarly expanded and contracted.
[0069]
FIG. 7 shows a signal format of the header area 31 (described above as the second header area) in the reproduction-only area. Secondly, the header area 31 is a data series having the same data arrangement and the same data capacity as the header area 21 and modulated by the same modulation code.
[0070]
The second header area 31 is followed by a 2-byte mirror area 130, followed by a second information data recording area 32. The detailed format of the second information data recording area 32 will be described below.
[0071]
In the data area 131, information data is recorded in advance by embossed pit rows. Therefore, this data area 131 can only be reproduced.
[0072]
The postamble area PA has a length longer than that required by the modulation method and a length that can terminate the recording mark. The postamble area PA is preferably 1 byte.
[0073]
In the second information data recording area 32, all the embossed pit rows are recorded in advance when the disc is manufactured. In contrast to this, the first information data recording area 22 is repeatedly recorded by the user using the recording marks. Therefore, the recording state of the second information data recording area 32 is more stable than the recording state of the first information data recording area 22. Therefore, in the second information data recording area 32, the gap area 122, the guard data area 126, and the buffer area 128 are not required.
[0074]
Therefore, the second information data recording area 32 has the same length as the first information data recording area 22 and the data area 131 has the same length as the data area 125. , The first dummy data is put in a location corresponding to the first buffer area, and the second dummy data is put in a location corresponding to the second buffer area.
[0075]
In the data format shown in FIG. 7, a 28-byte first pad area and a 1-byte postamble area are added as the first dummy area. These two areas correspond to the gap area and the first guard data area in the first information data recording area 22. Further, as described above, the length of the guard data area can be adjusted, and the position of the first dummy area is aligned with the center of the length of the variable guard data area range. The postamble area has a length (1 byte) longer than that required by the modulation method and records a pattern that can complete a recording code and a recording mark. In addition, the same pattern recorded in the VFO area (35 bytes) of the single wavelength pattern and the presync area (3 bytes) included in the first guard area is the VFO area (35 bytes of the single wavelength pattern in the first dummy area). ) And the presync area (3 bytes).
[0076]
Next, in order to create a second dummy area in the second data recording area 32 following the postamble area PA of the data area 131, an 80-byte second pad area and a 1-byte postamble are added. These two areas correspond to the second guard data area and the buffer area in the first information data recording area 22. Similar to the first dummy area, the position of the second dummy area is aligned with the center of the length of the corresponding variable guard data area range. The postamble area is recorded with a length (1 byte) longer than that required by the modulation method and a pattern capable of terminating the recording code and the recording mark.
[0077]
A predetermined specific pattern is recorded in the first pad area and the second pad area. As this pattern, for example, there is a single frequency pattern that repeats inversion at a constant cycle similar to the VFO region, a pattern by predetermined data, or the like.
[0078]
Returning to FIG. 4, it is assumed that the reading spot of the laser beam is traveling on the land track along the arrow A1. If it goes around the disk substantially, it proceeds toward the arrow A2, and eventually reaches the switching line 26. Next, if the switching line 26 is exceeded, the groove track is moved along the arrow B1. If it makes almost one turn, it proceeds toward the arrow B2 and reaches the switching line 26 again. In this manner, in the rewritable area 2, the land track and the groove track are alternately switched every round. The end track of the rewritable area 2 is configured such that the land 11 always comes. When the land 11 that is the end track ends, the end track is switched to the reproduction-only area 3 on the switching line 26. In addition, it is set so that no recording mark is attached to the end track of the rewritable area 2.
[0079]
Similarly, when switching from the read-only area 3 to the rewritable area 4, the land 11 is provided on the starting track of the rewritable area 4 and data writing to the land 11 is completely prohibited.
[0080]
FIG. 8 is a simple block diagram of a reproduction signal processing circuit for reproducing an optical disc having any one of the signal formats of FIG. 6 and FIG. In FIG. 8, a track 139 is a track of the groove 12 or land 11 on the optical disc 1. A split light detector 140 receives the reflected light from the track, and converts the reflected light from the uneven pits in the reproduction-only area and the recording marks in the rewritable area into a reproduction signal. Then, the sum signal of the split photodetector 140 is output by the operational amplifier 141, and the difference signal is output by the operational amplifier 142. The selection switch 143 switches between the sum signal and the difference signal and inputs to the binarization circuit 144.
[0081]
The difference signal output is detected by the envelope detector 145, and when the difference signal output exceeds a predetermined threshold value, the switch 143 is switched to the difference signal output side. In the signal format of FIG. 4, since the difference signal output is equal to or greater than a predetermined threshold only in the first header area 21 of the rewritable area, the switch is switched to the difference signal output side. When the first header area 21 is reproduced, the selection switch 143 outputs only the difference signal. In the first information data recording area 22 in the rewritable area and all areas in the reproduction-only area, the difference signal output is below a predetermined threshold value, so that the switch 143 outputs a sum signal during reproduction from these areas. Output.
[0082]
The digitizing circuit 144 operates according to threshold values set for the sum signal and the difference signal, and digitizes the reproduction signal. The PLL 152 extracts a reproduction clock from the digitized signal and inputs it to a PID regenerator 153 that reproduces each header area. The timing signal generator 154 outputs a gate signal for reading user data, and the digital signal is demodulated into binary data by the demodulator 155.
[0083]
(Second Embodiment) FIGS. 9 and 10 show a second embodiment of an optical disk having a rewritable area and a read-only area according to the present invention. The difference between the optical disk of the first embodiment and the optical disk of the second embodiment is that additional lands 11b and 11c are provided near the end track land 11a and the start track land 11s, and the format of data in the read-only area is set. The point is to change.
[0084]
First, the additional lands are described below. Recording of any kind of recording data on the additional lands 11b and 11c is prohibited. This recording prohibition is completed by writing information describing that recording in the read-only area 3 of the lead-in area 5 is prohibited.
[0085]
In the example shown in FIG. 9, the width Pc of the additional lands 11b and 11c is 3.26 m as an example. However, the width Pc is not so limited and can be selected appropriately. According to a preferred embodiment of the present invention, the width Pc is 0.68-5.42 m (including the numbers at both ends), and the terminal track land 11a and the additional land 11b are both referred to as a “coupling zone”. Similarly, both the starting track land 11s and the additional land 11c are referred to as “joining zone”. The coupling zone is a mirror area with high reflection.
[0086]
The installation of additional lands 11b and 11c simplifies the adjustment of the cutting machine when manufacturing the disc. In general, the cutting machine uses a first laser for making a rewritable area groove and address, and a second laser for making an embossed mark in the read-only area during the cutting operation. If the additional lands 11b and 11c are not installed as shown in FIGS. 2 and 4, it is necessary to switch from the first laser to the second laser during one rotation of the terminal track land 11a. Therefore, it is necessary to accurately maintain the arrangement of tracks in the rewritable area using the second laser and the arrangement of tracks in the reproduction-only area using the second laser. Therefore, a high degree of accuracy is required for positioning the beam spots of the first and second lasers. However, this adjustment is difficult. On the other hand, the installation of the additional land according to the present invention gives additional time to switching from the first laser to the second laser, and is dedicated to playback using an array of tracks in the rewritable area using the first laser and the second laser. It is unnecessary to keep the track arrangement of the area accurate. Furthermore, since the movement between the rewritable area and the reproduction-only area can be performed by a seek operation during reproduction, it is not necessary to maintain an accurate track arrangement in the rewritable area and the reproduction-only area. That is, no tracking management is required in the combined zone.
[0087]
Further, it should be noted that the widths of the additional lands 11b and 11c are about 10 times larger than the track pitch, and the entire surfaces of the additional lands 11b and 11c are mirror surfaces. Therefore, it becomes easy to detect the additional land during the seek operation. Since the additional land is located between each rewritable area and the reproduction-only area, there is a switch between the rewritable area and the reproduction-only area every time the optical head passes the additional land. Therefore, if the first accessed area located on the inner periphery of the disc is a rewritable area, it is easy to determine whether the optical head is currently located in the rewritable area or the read-only area when an additional land is detected. Can be detected.
[0088]
The detection signal corresponding to the additional land can be used as a tracking switching signal. This is because push-pull tracking control is used in the rewritable area and phase difference tracking control is used in the reproduction-only area.
[0089]
Furthermore, it should be noted that crosstalk between the rewritable area 2 and the reproduction-only area 3 can be avoided by providing an additional land.
[0090]
The data format of the playback-only area is described below.
[0091]
As shown in FIG. 10, there are M sectors 23 ′ in the read-only area 3 and N sectors 23 in the rewritable area 2. M is greater than N, and the difference between M and N depends on the radial distance from the center of the disk.
[0092]
FIG. 11 shows a schematic diagram of the format of the sector 23 'of the read-only area 3 shown in FIG.
[0093]
Each of the sectors 23 'includes 2418 bytes, and has the same format as the data area 23 of the sector 23 of the read-only area of the first embodiment. Of the 2418 bytes, 2048 bytes are user data, and the rest are error correction codes. Furthermore, each sector has many frames. Each frame has a length of 91 bytes, and a 2-byte synchronization code is added. One sector includes 26 frames. A 4-byte address code (ID) representing the logical address of the sector is assigned to the first frame of the sector. Following the address code (ID) is a 2-byte address code (ID) error detection code (IED), followed by a 6-byte reserved zone (RSV) that records various sector information.
[0094]
The sector of the read-only area of the second embodiment shown in FIG. 11 is different from the sector of the read-only area of the first embodiment shown in FIG. 7 in that the first dummy area and the second This is removal of the dummy area, simplification of the structure of the header area 31, and retention of the same format of the data area. It is obvious that the user data area of the read-only area of the optical disc shown in FIG. 11 is larger than that of the optical disc shown in FIG. Further, the data area 131 'format of the reproduction-only area shown in FIG. 11 is the same as that of the data area 125 of the rewritable area.
[0095]
FIG. 12 shows a simple block diagram of a reproduction signal processing circuit for reproducing the optical disk shown in FIGS. As shown in FIG. 12, the track of the optical disc 1 is scanned by the optical head 107. Data detected by the optical head 107 is digitized by the digital circuit 109, the reproduction clock is extracted by the PLL circuit, and the clock is applied to the switch 108. Data detected by the optical head is also sent to the additional land detector 113. Each time an additional land is detected, the additional land detector switches between terminals A and B of switch 108. Terminal A is connected to timing generator 111 and demodulator 112. Thereby, data from the rewritable area is processed. The terminal B is connected to the timing generator 115 and the demodulator 116. As a result, data from the reproduction-only area is processed.
[0096]
As described above, in the optical disc according to the second embodiment of the present invention, one rotation of the first track on the inner periphery side of the rewritable area is defined as the start track land. One rotation of the last track on the outer periphery side of the rewritable area is defined as a terminal track land. It is possible to catch either the header first half 24 or the header second half 25 in which a half track width is shifted from the groove track in the rewritable area adjacent to the start track land 11s and the end track land 11a. As a result, no crosstalk occurs between the shifted header portion data and the adjacent rewritable area data.
[0097]
Further, it is possible to easily detect between the rewritable area and the reproduction-only area.
[0098]
With the optical disc and signal format according to the present invention, the first header area can be reproduced in the rewritable area regardless of whether the groove track or the land track is tracked. For the optical disc according to the present invention, it is not necessary to provide separate header areas for the rewritable area groove track and land track.
[0099]
In addition, the same data format is used for the data area (2418 byte area) between the rewritable area and the reproduction-only area, so that sector management in the rewritable area is compatible with sector management in the reproduction-only area. You can hold it. As a result, the reproduction circuit can have a common circuit such as a digital circuit and a PLL circuit used for data from the rewritable area and the reproduction-dedicated area.
[0100]
The first header area and the second header area are formatted by the same modulation code using the same data string and the same data capacity, and the data format of the first data recording area is also rewritten according to the present invention. An optical disc including a possible area and a read-only area has the same data capacity as the data format of the second data recording area having data modulated using the same modulation code. Therefore, a common reproduction circuit can be used to reproduce signals from the rewritable area and the reproduction-only area. There is no need to provide two reproduction signal processing circuits (one for the rewritable area and the other for the reproduction-only area). Therefore, the required circuit scale is smaller than that of the conventional optical disk reproducing circuit. By using the optical disk according to the present invention, it is possible to realize a reproduction signal processing circuit with a simple circuit configuration and extremely high reliability.
[0101]
While the invention has been described above, it will be appreciated that various modifications can be made. Such variations are not to be regarded as a departure from the spirit and scope of the invention. Such variations readily conceivable to those skilled in the art are clearly included within the scope of the following claims.
[0102]
【The invention's effect】
The optical disc of the present invention has a configuration in which a land and a groove are switched on a switching line (a virtual line extending in the radial direction from the center of the optical disc). Switching between the rewritable area and the read-only area is always performed on the switching line. Done. This facilitates searching for tracks and managing (controlling) tracks. Also, the location of the switching line between the rewritable area and the reproduction-only area can be easily found.
[Brief description of the drawings]
FIG. 1 is a plan view of an optical disc according to a first embodiment of the present invention.
FIG. 2 is a partially enlarged perspective view of the optical disc according to the first embodiment of the present invention.
FIG. 3 is a plan view showing an outline of a track of the optical disc according to the first embodiment of the invention.
FIG. 4 is an enlarged plan view in the vicinity of a switching line between a rewritable area and a reproduction-only area of the optical disc according to the first embodiment of the present invention.
FIG. 5 is an enlarged explanatory diagram of an address portion in a rewritable area of the optical disc according to the present invention.
FIG. 6 is a detailed explanatory diagram of a data format of a sector area in a rewritable area.
FIG. 7 is a detailed explanatory diagram of a data format of a sector area in a read-only area according to the first embodiment of the present invention.
FIG. 8 is a block diagram of a reproducing circuit for an optical disc according to the first embodiment of the present invention.
FIG. 9 is a partially enlarged perspective view of an optical disc according to a second embodiment of the present invention.
FIG. 10 is an enlarged plan view in the vicinity of a switching line between a rewritable area and a read-only area of an optical disc according to a second embodiment of the present invention.
FIG. 11 is a detailed explanatory diagram of a data format of a sector area in a read-only area according to a second embodiment of the present invention.
FIG. 12 is a block diagram of an optical disc reproducing circuit according to a second embodiment of the present invention.
[Explanation of symbols]
1 optical disc, 2, 4, 7 rewritable area, 3, 6 playback-only area, 5 lead-in area, 8 data area, 10 substrate, 11 lands, 11a track lands at the end, 11b, 11c additional lands, 11s First track land, 12 groove, 13 recording mark, 14 land surface, 15 embossed mark, 16 phase change recording film, 17 light source, 18 lens, 21, 31 header area, 22, 32 information data recording area, 23 , 23 'sector, 24 header first half, 25 header second half, 26 switching line, 107 optical head, 108, 143 switch, 109 digital circuit, 110, 152 PLL circuit, 111, 115 timing generator, 112, 116, 155 Demodulator, 113 additional land detectors, 21, 130 Mirror area, 122 Gap area, 123, 126 Guard data area, 124 Single frequency pattern area, 125, 131 Data area, 128 Buffer area, 139 tracks, 140 split photodetector, 141, 142 operational amplifier, 144 2 Binary circuit, 145 envelope detector, 153 PID regenerator, 154 timing signal generator, AM address mark area, IED1, IED2, IED3, IED4 address error detection area, PA postamble area, PID1, PID2, PID3, PID4 area , Pid1, Pid2, Pid3, Pid4 address area, VFO1, VFO2, VFO3, VFO4 single frequency pattern area.

Claims (2)

A rewritable area having a recording track formed in a spiral shape in which lands and grooves are alternately connected on a switching line assumed on a predetermined radius and having a pitch Pa,
An optical disc having a read-only area in which information is recorded in advance by a continuous mark row on a recording track formed in a spiral shape having a pitch Pb,
The rewritable area has a plurality of recording sectors, and each recording sector has a header area pre-formatted with a mark representing address information and a data recording area for recording data,
The header area has 2K physical address areas PID _i (K is an integer of 2 or more ), and each physical address area PID _i has at least an address area Pid for storing sector address information and a predetermined repetition pattern. And a single frequency pattern region VFO recorded with
Physical address area _PID 1, · · PID _K are positioned shifted to the first radial direction of the optical disk by about Pa / 2 from the recording track on the groove, the physical address area _PID K + 1, ·· _{PID 2K} are on the grooves Is shifted from the recording track by about Pa / 2 in the second radial direction of the optical disc,
Physical address area _PID 1, the length of the single frequency pattern area VFO1 included in the physical address area PID ₁ beginning of · · PID _K are physical address area _PID 2, the physical address of the · · PID _K Configured to be longer than the length of the single frequency pattern VFO2 included in the region,
Physical address area _PID K + 1, the length of the single frequency pattern area VFO1 included in the physical address area _{PID K + 1} beginning of · · _{PID 2K} are physical address area _PID K + 2, the physical address of the · · _{PID 2K} Configured to be longer than the length of the single frequency pattern VFO2 included in the region,
An optical disc characterized in that the switching between the rewritable area and the read-only area is performed substantially along a switching line assumed on the radius. The optical disc of claim 1, wherein the optical disc upper Symbol Pa and Pb are characterized by a substantially equal this.

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