JP3260341B2 - Information recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium, and more particularly to a high-density information recording medium and a high-density optical recording medium whose track width is smaller than detecting means such as a light spot or a magnetic head.

[0002]

2. Description of the Related Art A conventional example of a medium for performing high-density (narrow track) recording is disclosed in, for example, JP-A-6-17.
No. 6404. In this example, as a recording medium, an optical recording medium having a groove portion and an inter-groove portion on a substrate and having an information recording area in both the groove portion and the inter-groove portion is used, and a boundary portion between the groove portion and the inter-groove portion is used. Pre-pits are arranged on the virtual extension line as identification information of a recording unit (sector). Thereby, the recording information is recorded in both the groove portion and the inter-groove portion, and the identification (address) information indicating the recording area is carried by the pre-pit, and one pre-pit is used for the pair of the groove portion and the inter-groove portion. Address information is shared. When this method is applied to, for example, a phase-change type recording medium or a magneto-optical recording medium, in the groove portion and the inter-groove portion, the information of the adjacent inter-groove portion or the groove portion is not mixed due to the interference effect in the light spot ( Since crosstalk is eliminated), there is a feature that the track can be narrowed and high-density recording can be performed.

[0003]

However, in the above conventional example, since information indicating the position on the medium is concentrated in the pre-pit portion, and since the pre-pit portions are discretely arranged, the pre-pit portions other than the above-mentioned pre-pit portion are not arranged. Location information cannot be obtained for the part. For this reason, it is difficult to control the speed of the disk precisely and with high reliability, and there is a problem particularly in terms of reliability against defects and the like.

A first object of the present invention is to solve the above problems and to provide a high-density, high-reliability information recording medium by allocating position information to portions other than the pre-pits. A second object of the present invention is to provide a high-density, high-reliability information recording / reproducing method by solving the above-mentioned problems and using an information recording medium in which position information is also assigned to portions other than the pre-pits. is there.

[0005]

According to the present invention, the following means are used in order to achieve the first object. (1) In an information recording medium having a substantially spiral or concentric track formed on a disk-shaped substrate by both a groove portion and a groove portion interposed between the groove portions, the recording medium is grouped into a plurality of regions in a radial direction. In each group, each track is divided into arc-shaped recording units of the same central angle radially aligned in the radial direction, and identification information indicating the recording unit is arranged for each recording unit, The arcs are grouped so that the length of the arc is approximately constant between the groups.
The groove portion and the inter-groove portion were formed by rocking (wobbling) in the radial direction.

[0006] With this, the identification information is provided for each recording unit, and the position information can be reliably obtained even in the recording portion by the swing of the groove portion and the inter-groove portion as the recording portion. This allows access and enables accurate positioning of recorded information. Further, since the recording units are arranged radially in the radial direction, access between tracks becomes easy, and crosstalk between positional information of each recording unit is minimized. Since the recording units are arranged so that the lengths of the arcs are substantially the same, the recording density becomes substantially uniform in the disk, and the entire surface of the disk can be used efficiently. In addition, precise correction of tracking deviation can be performed using this swing.

(2) The period and the phase of the swing of the groove portion and the inter-groove portion are radially aligned with the adjacent tracks in each group. As a result, the swing between adjacent tracks can be reliably reproduced without interference, and the width of each track becomes constant, so that the recording characteristics are not affected. (3) A constant integer multiple of the oscillation period of the groove portion and the inter-groove portion is set to match the length of the arc-shaped recording unit. This makes it possible to reliably detect the start point and the end point of the recording unit by using the oscillation cycle, and to detect an accurate position in the recording unit. In addition, since the length of the recording unit and the oscillation period are synchronized, by controlling the oscillation frequency to be constant, it is possible to automatically keep the relative speed of the recording medium constant at all times.

(4) The maximum value of the swing amplitude of the groove and the space between the grooves is made smaller than 1/10 of the track width. Thereby, the influence of the swing on the recording / reproducing characteristics is reduced by one.
−cos (180/10) = − 26 dB or less, and the S / N (〜20 dB) required for normal recording and reproduction
The effect on B) can be suppressed to a negligible level.

(5) The identification information is formed by pre-pits, which are minute concaves or convexes disposed at the portions where the grooves and the spaces between the grooves are interrupted. This facilitates mass production of the information recording medium provided with the identification information in advance by a simple manufacturing process such as injection molding, thereby improving the productivity of the information recording medium.

(6) The identification information is arranged at an intermediate portion between the track and a track adjacent to the track. Thereby, one piece of identification information can be shared by two tracks, so that the identification information assigned to one information area is duplicated, and the reliability is improved. Whether the identification information is located on the left or right of the information track can be identified by using a difference in position in the direction along the track. Further, since the relationship between the identification information of the adjacent track and the identification information of the track has a certain relationship, the track can be identified from the identification information of the adjacent track.

(7) The groove track and the inter-groove track are
At least one portion per circumference was arranged so as to be connected to each other from the groove to the groove or from the groove to the groove. This makes it possible to continuously access the groove recording track from the groove recording track, thereby improving the effective transfer speed of information and recording continuous information such as moving image information without any breaks. Reproduction becomes easy. In the present invention, the following means are used to achieve the second object.

(8) Using the above-described recording medium, light is irradiated to the track, and the reflected light of the light is detected by a photodetector divided into at least two parts, thereby detecting a swing signal. Recording / reproduction is performed by controlling the rotation of the recording medium so that the signal period is constant. This makes it possible to easily and accurately control the rotation of the disk-shaped medium so that the speed of the light spot on the recording medium becomes substantially constant.

(9) Using the above-described recording medium, a track is irradiated with light, and the reflected light of the light is detected by at least two divided photodetectors, thereby detecting a swing signal, and Recording was performed using a clock generated so as to be synchronized with the signal phase. This makes it easy to keep the length of each recording unit on the recording medium constant, so that the length of the extra gap on the recording medium can be minimized.

(10) The above recording medium is used to irradiate light to a track, and the reflected light of the light is detected by a photodetector divided into at least two parts, thereby detecting a swing signal and detecting division. Track deviation is detected by comparing the amplitude of the swing signal obtained by each detector of the detector. As a result, recording / reproduction can always be performed while monitoring the track deviation amount, so that the reliability of the positioning servo is dramatically improved.

(11) An optical disk having a concentric or spiral groove structure along a track, the groove structure swinging in the radial direction of the optical disk, and the track of the optical disk is a track at a radial boundary. The recording unit is divided into a plurality of recording units in the direction, and among the recording units divided by the radial boundary line, one in which at least two recording units adjacent in the radial direction of the optical disk constitute one zone is used. In one zone, the number of swings of the groove structure included in each recording unit was made substantially the same.

As a result, the position information can be reliably obtained even in the recording section by the swing, so that the recorded information can be accessed with certainty and the position of the recorded information can be accurately positioned. Further, since the recording units are radially aligned in the group (zone) in the radial direction, access between tracks is facilitated, and crosstalk between positional information of each recording unit is minimized. The recording unit here does not necessarily need to match the length of the sector. For example, two or more sectors may be collectively used as a recording unit. The recording unit may be a logical sector or a logical block for error correction by grouping a plurality of units. In any case, the recording unit referred to here is an area of a substantially constant length provided in the disc.

(12) An optical disk having a concentric or spiral groove structure along a track, the groove structure oscillating in the radial direction of the optical disk, and the track of the optical disk has a radial boundary line. The optical disk is divided into a plurality of recording units in the circumferential direction, and one zone is constituted by at least two recording units radially adjacent to each other among recording units divided by a radial boundary line. Zones were included, and the number of swings of the groove structure included in one unit was almost the same in any zone.

As a result, the relationship between the information recording unit and the length of the swing becomes equal over the entire surface of the disk, so that the signal obtained from the swing is used without switching between zones to control the rotational speed and to record the clock signal. Can be generated. For this reason, the density in the disk can be made substantially uniform with a device having a simple configuration, and it is easy to efficiently use the entire surface of the disk.

(13) An optical disk having a concentric or spiral groove structure, wherein the groove structure swings in the radial direction of the optical disk, and the groove structure of the optical disk is a radial boundary line in the circumferential direction of the optical disk. The recording unit is divided into a plurality of recording units, and at least two recording units radially adjacent to each other among the recording units divided by a radial boundary line constitute one zone. The rocking periods of the groove structures adjacent in the radial direction are configured to be substantially the same. Or

(14) An optical disk having a concentric or spiral groove structure, wherein the groove structure oscillates in the radial direction of the optical disk, and the groove structure of the optical disk has a radial boundary line around the optical disk. The recording unit is divided into a plurality of recording units in the direction, and at least two recording units radially adjacent to each other among the recording units divided by the radial boundary line constitute one zone, and light is emitted within one zone. The period of the rocking of the groove structure is substantially the same between the unit areas adjacent to each other in the disk radial direction, and the number of times of the rocking is the same.

Thus, since the position information can be reliably obtained in the recording section, the recorded information can be reliably accessed and the position of the recorded information can be accurately positioned. further,
Swing is radially aligned within the group (zone) in the radial direction, and the phase of the swing is aligned between the grooves, making it easy to access between tracks and detecting the swing with high signal quality. It becomes easier to do. Strictly speaking, this oscillation has a period that is proportional to the radial position of the groove in one zone, but it is almost the same for grooves that are close to each other like grooves in one zone. good. Note that the number of swings does not necessarily have to be an integer within a unit area.

(15) An optical disk having a concentric or spiral groove structure, wherein the groove structure swings in the radial direction of the optical disk, and the groove structure of the optical disk is a radial boundary line in the circumferential direction of the optical disk. The recording unit is divided into a plurality of recording units, and one zone is constituted by at least two recording units that are radially adjacent to each other among the recording units divided by a radial boundary line. In all the zones, the unit regions adjacent to each other in the radial direction of the optical disk have substantially the same period of the rocking of the groove structure and the same number of times of rocking.

As a result, the relationship between the unit of information recording and the length of the swing becomes equal on the entire surface of the disk. Therefore, by using the signal obtained from the swing without switching between zones, it is possible to control the rotation speed and record. Since it is possible to generate a clock, it is possible to make the density in the disk substantially uniform with a device having a simple configuration,
It is easy to efficiently use the entire disk.

(16) An optical disk having a concentric or spiral groove structure along a track, wherein the groove structure oscillates in the radial direction of the optical disk, and the track of the optical disk has a radial boundary at the track direction. The recording unit is divided into a plurality of recording units, and at least two recording units adjacent in the radial direction of the optical disk among the recording units divided by the radial boundary line constitute one zone. The center angle corresponding to one cycle of the oscillation of the groove structure included in each recording unit was the same, and the wobble start positions in each recording unit were radially aligned in the radial direction. As a result, the swing between adjacent tracks can be reliably reproduced without interference, and the width of each track becomes constant, so that the recording characteristics are not affected.

(17) An optical disk having a concentric or spiral groove structure along a track, wherein the groove structure swings in the radial direction of the optical disk, and the track of the optical disk has a radial boundary line. The recording unit is divided into a plurality of recording units in the circumferential direction of the optical disc, and at least two recording units which are radially adjacent to each other among the recording units divided by a radial boundary line.
One zone is composed of one recording unit, and when N is one integer common to all recording units on the optical disk, the optical disk is assumed to include a plurality of zones, and one recording of each zone is performed. The period of all swings included in the unit was set to be approximately 1 / N times the length of the recording unit.

As a result, the relationship between the unit of information recording and the length of the swing becomes equal on the entire surface of the disk. Therefore, by using the signal obtained from the swing without switching between zones, it is possible to control the rotation speed and record. Since the clock can be generated, the density in the disk can be made substantially uniform with a device having a simple configuration. Therefore, it is easy to efficiently use the entire surface of the disk. In addition, since the integral multiple of the oscillation period is equal to the length of the recording unit, the oscillation phase can be connected to an adjacent recording unit without any irregularity. It is easy to generate a timing signal such as a clock over a recording unit to be recorded. The fact that the swings are connected without any irregularity means that the phases of the swings are continuous between adjacent recording units, and the swings are always physically connected continuously. No need. In other words, a structure in which the oscillation is lost for several periods at the boundary between the recording units may be used. However, if the missing portion is supplemented (supplemented), the adjacent recording unit areas will be
What is necessary is just to be comprised so that the phase of oscillation may be connected continuously.

(18) Identification information is provided for each recording unit. This makes it easy to access the recording unit on the disk, and identifies the position of the light spot at all positions on the disk by combining the signal detected from the swing with the identification information. Becomes possible, the reliability of recording and reproduction is improved, and the positioning accuracy of the recorded information on the recording medium can be improved, so that the buffer area at the time of recording can be reduced, and as a result, As a result, it is possible to increase the recording capacity. Also,
Even if a part of the identification information on the disc cannot be detected due to a defect or the like, the light spot position can be identified by the light spot position information obtained from the swing, so that the reliability of recording and reproduction is dramatically improved. By utilizing this fact, for example, the reliability of recording and reproduction can be ensured without performing any inspection on the recording medium at the time of shipping the medium, so that the cost of the recording medium can be greatly reduced. .
In addition, it is extremely resistant to dirt, so that it is not necessary to protect it by putting it in a case or the like. For this reason, it becomes possible to provide a low-cost medium.

(19) The above identification information is formed by pre-pits comprising optical concaves or convexes. This makes it easy to mass-produce disks by the replica method, etc.
It is possible to provide stable and reliable identification information that does not deteriorate.

(20) An information recording area is provided along the center line of the groove structure and the center line between the groove structures. This makes it possible to arrange recording information at a high density. That is, a high density (large capacity) medium can be realized.

(21) The recording medium is irradiated with light, and the reflected light is detected by a photodetector, thereby detecting a swing signal, and using the swing signal, a recording or reproduction timing signal is detected. I decided to get it. Accordingly, the position information can be reliably obtained even in the recording portion by the swing of the groove portion and the inter-groove portion, which is the recording portion, so that the recording information can be securely accessed and the accurate positioning of the recording information can be performed. That is, the reliability of recording and reproduction and the recording accuracy are improved.

(22) By irradiating the recording medium with light and detecting the reflected light of the light with a photodetector, an oscillating signal is detected, and at least the recorded information and the identification information are identified by using the oscillating signal. It was decided to obtain the start or end timing of any recording or reproduction. Due to the swing of the groove and the groove between the recording portions, the timing information can be obtained even when the recording unit and the appearance timing of the identification signal are not constant because the rotation speed of the disc is not stable. Is reliably obtained, so that the recorded information can be securely accessed. For this reason, access speed is improved,
Since an inexpensive motor can be used, the cost of the apparatus can be reduced.

(23) At least one piece of identification information is detected by irradiating the recording medium with light, and when detecting at least one piece of subsequent identification information following the identification information, it is determined that the subsequent identification information has been detected. The identification information detection signal shown, or, using the pseudo-subsequent identification information detection signal generated using the recording or reproduction timing signal obtained from the above-mentioned swing, the recording of the recording area to be identified by the subsequent identification information or Playback was decided. As a result, even when the subsequent identification information cannot be detected due to a defect or dirt,
Since the recording area to be identified by the subsequent identification information can be accessed using the signal obtained from the swing, the reliability of recording and reproduction is dramatically improved.

(24) When detecting the identification information by irradiating the recording medium with light, if the identification information cannot be detected, the timing signal obtained from the swing is used as a substitute for the identification information to record or record. An information recording / reproducing method characterized by performing reproduction. As a result, due to defects or dirt,
Even when the subsequent identification information cannot be detected, the recording area can be securely accessed using the swing signal, so that the reliability of recording and reproduction is dramatically improved. For this reason, for example, the reliability of recording / reproduction can be ensured without performing any inspection on the recording medium when the medium is shipped, so that the cost of the recording medium can be significantly reduced.
In addition, it is extremely resistant to dirt, so that it is not necessary to protect it by putting it in a case or the like. For this reason, it becomes possible to provide a low-cost medium.

(25) The recording medium is irradiated with light, and the reflected light of the light is detected by a photodetector to detect a swing signal, and a recording or reproduction timing signal is generated from the swing signal. At this time, at least a portion where the identification information is arranged is interpolated by a signal synchronized with a series of immediately preceding swing signals. Thereby, the recording / reproducing timing signal obtained from the swing information is not disturbed by the identification signal of the identification information section, and the position information from the swing information can be reliably obtained even at a position immediately after the identification information. . That is, this makes it possible to reliably access the area immediately after the undetectable identification information, thereby ensuring the reliability of recording and reproduction. That is, real-time recording / reproduction and highly reliable recording can be performed without any loss of information.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Information Recording Medium FIG. 5 shows the arrangement of tracks and sectors on a recording medium according to the present invention. A plurality of groups 91, 92, 93 are arranged in the radial direction of the disk-shaped recording medium 8. The track 3 is wobbled by a small amount in the radial direction. Each track is divided into a plurality of arc-shaped sectors (recording units) 1 aligned in the radial direction. As the length of the arc-shaped sector 1 becomes substantially constant irrespective of the group, the number of divisions of the sector per circumference increases as the group is located at a position with a larger radius.

FIG. 1 shows an example of the arrangement of tracks in one group of the information recording medium of the present invention. The groove information tracks 3 having a width of 0.7 μm and the depth of 60 nm and the inter-groove information tracks 4 having a width of 0.7 μm are alternately arranged. The groove information track 3 and the inter-groove information track 4 are connected to each other by a switching unit 5. That is, the groove 3 is configured to be connected to the adjacent groove 3 after one round of the track, and the groove 4 is configured to be connected to the adjacent groove 3 after the circle of the track. Each track is divided into a plurality of arc-shaped recording units 1 such as sectors, and identification information 2 is arranged at the head of each information recording unit 1. In this example, the length of the sector is about 8 mm and 20
This corresponds to a user capacity of 48 bytes. The groove portion and the inter-groove portion are wobbled in the radial direction with an amplitude of about 20 nm. The cycle of the wobble was set to 1/145 of the sector length, that is, about 55 μm. The ratio of 1: 145 was selected such that the wobble period became an integral multiple of the length of the recording data (channel bit length). This makes it easy to generate a recording clock from the wobble.

FIGS. 2 and 3 are enlarged partial plan views of each information identification information portion. FIG. 2 shows a portion 6 in which tracks before and after the identification information are connected by a groove portion and a groove portion.
FIG. 3 shows a portion where the front and rear tracks are connected at the groove portion and the inter-groove portion, that is, the identification information is different between adjacent tracks at positions in the direction along the information track, and
It is arranged so as to coincide with the next track. In FIG. 2, the identification information includes a first position 21 and a second position 22.
Are radially aligned at two locations in the radial direction. The front and rear tracks are connected by a groove 3 and a groove 4. In the example of this figure, each piece of identification information corresponds to the recording area of the information track on the right side. Further, the identification information corresponding to the groove information track 3 on the right side of the figure is located at a first position 21, and the identification information corresponding to the inter-groove information track 4 is located at a second position 22. That is, the identification information is arranged such that the position in the direction along the information track is different between adjacent tracks and coincides with the two adjacent tracks.

In the switching section 5 shown in FIG. 3, tracks before and after the identification information are connected to each other at the groove portion and the inter-groove portion. Also in this case, each piece of identification information corresponds to the recording area of the information track on the right side, and the identification information corresponding to the groove information track 3 on the right side of the figure is located at the first position 21 and the groove information track 4 is located at the first position 21. The corresponding identification information is located at the second position 22.

For this reason, for example, when the light spot 7 scans on the inter-groove portion 4, only one of the pits is always reproduced, and there is no fear that crosstalk from an adjacent track will occur. Therefore, it is possible to satisfactorily reproduce the address information allocated to the pre-pits without crosstalk. The pre-pit address information is 8 / in this example.
It is recorded by 16 modulation codes (channel bit length: 0.2 μm).

FIG. 4 is a perspective view of the configuration of the track and the identification information according to the present embodiment, and shows that the identification information is formed by small pits (pits) 23. In the present embodiment, the pits 23 are evenly arranged on both sides of the track (land portion or groove portion), so that the pits 23 cancel out the influence on the tracking servo signal. Therefore, the track offset can be kept sufficiently small. Further, for example,
When the inter-groove portion 4 is reproduced, the address information of the first pre-pit portion 21 and the address information of the second pre-pit portion 22 are reproduced continuously. Therefore, by arranging information so that address information is obtained by combining the two, an address (track number), that is, identification information can be set independently of the inter-groove portion 4 and the groove portion 3. . That is, the first
By continuously reproducing the address information of the pre-pit portion 21 and the second pre-pit portion 22, the land portion and the groove portion can be identified.

FIG. 6 shows a specific example of identification information numbering.
Shown in The identification information of the recording area 11 and the recording area 12 is shown. In this example, information is recorded / reproduced while relatively scanning the detected spot from left to right. For example, the groove track K on the left side is connected to the inter-groove track K + 1 on the right side of the switching unit 5. The left inter-groove track K + 1 is continuous after one round of this track. In this example, for example, the identification information of the information recording area 81 of the groove track K is N-1 + S. Here, S indicates the sum of optical recording information units per track circumference. When the identification information section 6 of this track is reproduced by a light spot or the like, N-1 + 2S is reproduced as identification information at the first position, and N-1 + S is reproduced as identification information at the second position. In this case, by determining that the smaller number is always used as the recording area number, N-1-S is adopted as the identification information of the information recording area 81 of the groove track K. Similarly, when the inter-groove track K-1 is scanned, N-1 is adopted as the identification information at the first position as the identification information. At the same time, it is possible to distinguish between the groove portion and the inter-groove portion depending on whether the identification information at the first position or the identification information at the second position is employed.

When the information track in the track switching section 5 is reproduced, the correspondence between the identification information and the recording information and the determination of the groove portion and the inter-groove portion can be performed in the same manner. Therefore, the following polarity can be switched between the groove track and the groove track by utilizing this relationship. In this example, the case where the identification information part is the first and second two sets is shown, but any number may be used as long as it is a plurality of sets. For example, in the case of four sets, the first and third pre-pit parts are placed on the lower side of the groove. And the second and fourth pre-pits may be arranged above the groove.
By increasing the number of pre-pit portions, reliability against defects and the like is improved. Here, a phase-change recording film (GeSbTe) was used as the recording film. Therefore, the recording mark is formed in the form of an amorphous region.

Second Embodiment Information Recording / Reproducing Method An example of a recording / reproducing method using the recording medium of the first embodiment is shown in FIG.
This will be described with reference to FIG. The recording medium 8 of the first embodiment is
Rotated by 2. The light intensity control means 171 controls the light generation means 131 to generate the light 122 so that the light intensity is instructed by the central control means 151, and the light
Numeral 22 is condensed by the condensing means 132 to form the light spot 7 on the information recording medium 8. Using the reflected light 123 from the light spot 7, the light is detected by the light detecting means 133.
This light detecting means is composed of a plurality of divided photodetectors. The reproducing means 191 reproduces information on the medium using the reproduced signal 130 from the photodetector. To detect the wobble of the track on the medium, the differential output between the outputs of the multi-segment detector is used. This is based on the fact that the intensity distribution of the diffracted light from the light spot changes depending on the positional relationship between the light spot and the track. Based on the wobble signal detected by the reproducing means, information on the positional relationship between the spot and the track, and further based on the pre-pit identification information,
The position control means 161 controls the position of the light condensing means 132 and controls the rotation frequency of the motor 162. The control of the rotation frequency is performed so that the frequency of the reproduced wobble signal becomes a predetermined constant value. By performing the rotation control in this manner, the motor can be automatically controlled at an appropriate rotation speed irrespective of the group on the medium, and the rotation information is about 55 μm in one cycle. The rotation information density is very high,
High-precision rotation control becomes possible. Further, since the rotation information is arranged throughout one rotation of the disk, even if a part of the rotation information is lost due to dirt or defect, it can be reproduced with high reliability without any problem.

<< Embodiment 3 >> Information Recording / Reproducing Method A method for recording / reproducing by generating a clock synchronized with the phase of a wobble signal at the time of recording / reproducing information will be described. To generate this clock, a PLL (Phase-Lo
cked Loop) circuit. Since this clock is accurately synchronized with the wobble information of the recording medium, by performing recording and reproduction using this clock, recording and reproduction can be performed at a timing completely synchronized with the position on the medium. Recording / reproduction can be performed without providing an unnecessary buffer area on the recording medium, a medium with high format efficiency can be used, and the recording capacity is improved. Further, since the wobble information (rotation information) is arranged everywhere in one rotation of the disk, even if a part of the wobble information is lost due to dirt or defect, it can be reproduced with high reliability without any problem.

Embodiment 4 Information Recording Medium FIG. 5 shows a track and sector arrangement of a recording medium according to an embodiment of the present invention. Disc-shaped recording medium 8 having a diameter of 120 mm
A plurality of zones (groups) 91, 92, 9 in the radial direction of
3 are arranged. In this example, a radius of about 24 mm to 58 mm was divided into 24 zones. Therefore,
The width of a zone occupied by one zone is about 1.4 mm. The track 3 is wobbled by a small amount in the radial direction. Each track is divided into a plurality of arc-shaped sectors (recording units) 1 aligned in the radial direction. As the length of the arc-shaped sector 1 becomes substantially constant irrespective of the zone (group), the number of divisions of one peripheral sector increases as the radius of the zone increases. In this embodiment, the recording area is divided into 17 recording units 1 per circumference in a zone (innermost peripheral zone) around a radius of 25 mm, and the number of divisions increases by one as moving to the outer peripheral zone. I have to. By using recording media grouped such that the number of divisions on the outer periphery is increased, the length of the recording unit 1 on the inner and outer periphery can be made substantially constant, that is, the density can be made substantially constant, Surface area can be used effectively. In addition, since recording and reproduction can be controlled at the same rotation speed and recording frequency in each group, the configuration of an apparatus using a medium is simplified. Of course, the length of the recording unit is slightly different between the inside and outside of each zone.

FIG. 1 shows an example of the arrangement of tracks in one group of the information recording medium of the present invention. 0.74 μm width,
A groove information track 3 having a depth of 60 nm and a width of 0.74 μm
Are arranged alternately. In each zone, approximately 950 groove tracks and the same number of inter-groove tracks are arranged. The groove information track 3 and the inter-groove information track 4 are connected to each other by a switching section 5 located at one place around the circumference of the disk. That is, the groove 3 is configured to be connected to the adjacent groove 3 after one round of the track, and the groove 4 is configured to be connected to the adjacent groove 3 after the circle of the track. Each track is divided into a plurality of arc-shaped recording units 1, and identification information 2 is arranged at the head of each information recording unit 1. In this example, the length of the recording unit is about 8.5 mm, which corresponds to a user capacity of 2048 bytes.

The groove and the space between the grooves are wobbled in the radial direction with a half-value amplitude of about 20 nm. The wobble period was set to 1/232 of the sector length, that is, about 37 μm. Here, the ratio of 1: 232 is set to this value not only in one group (zone) but also in all recording units on the disc. This 1: 2
The ratio of 32 indicates that the wobble period is an integral multiple of the unit length (channel bit length) of the recording data (186 in this example).
Times). Therefore, when the length of the recording unit is represented by the number of channel bits, 232 × 186 = 43152.
It corresponds to a channel bit. Since the wobble period is an integral multiple of the recording channel bit, a recording clock can be easily generated by multiplying the wobble frequency by an integer. Further, since the relationship between the information recording unit 1 and the length of the swing becomes equal on the entire surface of the disk, the recording clock can be generated by using the signal obtained from the swing without switching between zones. Therefore, the density in the disk can be made substantially uniform with a device having a simple configuration, and it is easy to efficiently use the entire surface of the disk. Furthermore, by performing rotation control so that the frequency of this wobble becomes constant,
Regardless of the position of the recording medium, the relative linear velocity between the light spot and the medium can be controlled to be substantially constant. in this way,
By controlling the linear velocity to be substantially constant, recording and reproduction can be performed under the same recording conditions regardless of the location of the medium.
Since the control of the recording and reproducing characteristics of the medium is simplified, the recording device and the medium can be easily configured. Here, since the length of the recording area 1 is slightly different between the inside and outside of the zone,
Needless to say, the length of the wobble in a period of one integral number of the recording unit also differs between the inner and outer peripheries of the zone, and the linear velocity slightly changes accordingly. However, since the central angle formed by the recording unit in the zone is constant, the rotation speed (angular velocity) in the zone is constant, so that high-speed access in the zone is possible.

In this case, since the integral multiple (232 times) of the period of the wobble (oscillation) coincides with the length of the recording unit 1, the oscillation between the adjacent recording units 1 is performed. Can be connected without any odd part, so that it is easy to generate a timing signal such as a clock over the continuous recording unit 1 using the swing. this,
The fact that the swings are connected without any irregularity means that the phases of the swings are continuous between the adjacent recording units 1, and it is necessary that the swings are physically connected continuously. There is no. That is, a structure in which the oscillation is lost over several periods at the boundary portion of the recording unit 1 may be used. In this case, if the missing portion is supplemented, the adjacent recording unit regions 1 can be used together. It is sufficient if the phase of the swing is continuously connected. Actually, in the present embodiment, the identification information 2 composed of pre-pits is arranged at the head of the recording unit, and neither the groove 3 nor the inter-groove 4 exists, so that no wobble is formed. For this identification information 2, the wobble is missing for about 11.2 cycles. Therefore, the number of wobbles actually present is about 220.8, but the length of the recording information unit is set to be exactly 232 times the wobble period.

Here, the recording unit referred to in the present embodiment does not necessarily have to match the length of a sector. For example, identification information may be arranged as a recording unit by combining two or more sectors. The recording unit may be a logical sector or a logical block for error correction by grouping a plurality of units. In any case, the recording unit referred to in the present embodiment is an area having a substantially constant length in which identification information is arranged at the head.

FIGS. 2 and 3 are enlarged partial plan views of each information identification information portion. FIG. 2 shows a portion 6 in which tracks before and after the identification information are connected by a groove portion and a groove portion.
FIG. 3 shows a portion where the front and rear tracks are connected at the groove portion and the inter-groove portion, that is, the identification information has different positions in the direction along the information track between adjacent tracks, and is different from the two tracks. The portions that are arranged to match are shown. In FIG. 2, the identification information is radially arranged at two locations, a first location 21 and a second location 22, in the radial direction. The front and rear tracks are connected by a groove 3 and a groove 4. In the example of this figure, each piece of identification information corresponds to the recording area of the information track on the right side. Further, the identification information corresponding to the groove information track 3 on the right side of the figure is located at a first position 21, and the identification information corresponding to the inter-groove information track 4 is located at a second position 22. That is, the identification information is arranged such that the position in the direction along the information track is different between adjacent tracks and coincides with the two adjacent tracks.

The wobbles are formed so as to have a sine wave shape starting at the same phase for all the information tracks, and start immediately after the identification information section or start through a slight buffer area. Has become. In this way, when the points at which the phase of the sinusoidal wobble becomes 0 degree are connected by adjacent tracks, they are radially arranged in the radial direction. For this reason, the track width does not change due to the wobble. For this reason, there is no fear that the wobble adversely affects the recording / reproducing characteristics. If the phases of the wobbles are not aligned in each track, a portion where the width of the track is modulated by the wobbles is formed, which greatly affects the recording / reproducing characteristics. Therefore, as in the present invention, it is very important for the realization of the present invention that the phases of the wobbles (including the polarity) between adjacent tracks are aligned.

In the switching section 5 of FIG. 3, tracks before and after the identification information are connected to each other at the groove portion and the inter-groove portion. In this case as well, each piece of identification information corresponds to the recording area of the information track on the right side, and the identification information corresponding to the groove information track 3 on the right side of FIG. Are arranged at the second position 22.

For this reason, for example, when the light spot 7 scans on the inter-groove portion 4, only one of the pits is always reproduced, and there is no fear that crosstalk from an adjacent track will occur. Therefore, it is possible to satisfactorily reproduce the address information allocated to the pre-pits without crosstalk. The pre-pit address information is 8 / in this example.
It is recorded by 16 modulation codes (channel bit length: 0.2 μm). Therefore, the shortest pit length is about 0.6 μm. From the viewpoint of simplification of the recording / reproducing apparatus, it is desirable that the modulation code of the pre-pit portion and the modulation code of the recording portion of the user information be the same. In this embodiment, the modulation code
Both recording linear densities are the same. Therefore, most of the circuits can be shared.

FIG. 4 is a perspective view of the configuration of the track and the identification information according to the present embodiment, and shows that the identification information is formed by small pits (pits) 23. In the present embodiment, the pits 23 are evenly arranged on both sides of the track (land portion or groove portion), so that the pits 23 cancel out the influence on the tracking servo signal. Therefore, the track offset can be kept sufficiently small. Further, for example,
When the inter-groove portion 4 is reproduced, the address information of the first pre-pit portion 21 and the address information of the second pre-pit portion 22 are reproduced continuously. Therefore, by arranging information so that address information is obtained by combining the two, an address (track number), that is, identification information can be set independently of the inter-groove portion 4 and the groove portion 3. . That is, the first
By continuously reproducing the address information of the pre-pit portion 21 and the second pre-pit portion 22, the land portion and the groove portion can be identified.

FIG. 6 shows a specific example of numbering of identification information.
Shown in The identification information of the recording area 11 and the recording area 12 is shown. In this example, information is recorded / reproduced while relatively scanning the detected spot from left to right. For example, the groove track K on the left side is connected to the inter-groove track K + 1 on the right side of the switching unit 5. The left inter-groove track K + 1 is continuous after one round of this track. In this example, for example, the identification information of the information recording area 81 of the groove track K is N-1 + S. Here, S indicates the sum of optical recording information units around one track. When the identification information section 6 of this track is reproduced by a light spot or the like, N-1 + 2S is reproduced as identification information at the first position, and N-1 + S is reproduced as identification information at the second position. in this case,
By determining to always use the smaller number as the recording area number, N-1-S is adopted as the identification information of the information recording area 81 of the groove track K. Similarly, when the inter-groove track K-1 is scanned, N-1 is adopted as the identification information at the first position as the identification information. At the same time, it is possible to distinguish between the groove portion and the inter-groove portion depending on whether the identification information at the first position or the identification information at the second position is employed.

When an information track in the track switching section 5 is reproduced, the correspondence between the identification information and the recording area and the determination of the groove portion and the groove portion can be performed in the same manner. Therefore, the following polarity can be switched between the groove track and the groove track by utilizing this relationship. In this example, the case where the identification information part is the first and second two sets is shown, but any number may be used as long as it is a plurality of sets. For example, in the case of four sets, the first and second pre-pit parts are located below the groove. (Radially inward), and the third and fourth pre-pits may be disposed above the groove (radially outward). Or, first,
The third pre-pit portion may be arranged below the groove, and the second and fourth pre-pits may be arranged above the groove. By increasing the number of pre-pit portions, reliability against defects and the like is improved. Here, a phase change type recording film (Ge
SbTe) was used. Therefore, the recording mark is formed in the form of an amorphous region.

Fifth Embodiment Information Recording / Reproducing Method An example in which recording / reproducing is performed by the apparatus shown in FIG. 7 using the recording medium of the fourth embodiment will be described below. The recording medium 8 of the fourth embodiment is rotated by a motor 162. The light intensity control means 1 is controlled so that the light intensity is instructed by the central control means 151.
Reference numeral 71 controls the light generating means 131 to generate light 122. The light 122 is condensed by the condensing means 132 to form the light spot 7 on the information recording medium 8. Using the reflected light 123 from the light spot 7, the light detecting means 133 is used.
To detect. This light detecting means is composed of a plurality of divided photodetectors. The reproducing means 191 reproduces information on the medium using the reproduced signal 130 from the photodetector. To detect the wobble of the track on the medium, the differential output between the outputs of the multi-segment detector is used. This is based on the fact that the intensity distribution of the diffracted light from the light spot changes depending on the positional relationship between the light spot and the track.
Based on the wobble signal detected by the reproducing means, information on the positional relationship between the spot and the track, and further on the pre-pit identification information, the position control means 161 controls the position of the light condensing means 132 and the rotational frequency of the motor 162. Control. The control of the rotation frequency is performed so that the frequency of the reproduced wobble signal becomes a predetermined constant value. In this way, by performing the rotation control, the motor can be automatically controlled at an appropriate rotation speed regardless of the zone on the medium.
Since one cycle is 7 μm, the density of rotation information is extremely high, and high-precision rotation control is possible. Further, since the rotation information is arranged throughout one rotation of the disk, even if a part of the rotation information is lost due to dirt or defect, it can be reproduced with high reliability without any problem.

FIG. 8 shows an example of the reproduced signal 41 of the wobble information and the reproduced signal 42 of the identification information section. Here, it is assumed that the number of the identification information units is four. 1st, 2nd
It is assumed that the identification information 31 and 32 are on the lower side of the groove, and the third and fourth identification information 33 and 34 are on the upper side. In this example, a photodetector divided into at least two in the radial direction is used as a detector, and a differential signal between the two detectors is obtained. That is, a detection system similar to the push-pull signal detection system used for normal tracking control and the like was used. However, since the frequencies of the wobble signal and the identification information signal are higher than the band for the tracking servo, an amplifying device and a differential circuit of a high frequency specification were prepared. Reproduction signals 421, 422, 423, and 424 were obtained corresponding to the first, second, third, and fourth identification information 31, 32, 33, and 34, respectively.
When the light spot does not cover the pre-pits of the identification information portion, the reflected light is evenly incident on the above-mentioned split detector, so that the reproduced signal (differential signal) output is almost zero.
In the state where the light spot partially overlaps the pre-pit (FIG. 2), the distribution of the reflected light from the light spot is largely biased due to the diffraction effect, and the output of the split detector is unbalanced. A differential signal output is obtained. Since the direction of the deviation at this time differs depending on the positional relationship between the light spot and the pits, the polarities of the differential outputs corresponding to the identification information 31 and 32 and the differential outputs corresponding to the identification information 33 and 34 are inverted. Therefore, even if this polarity is used, it is possible to identify which track of the groove or the groove is located at the light spot. The identification information is obtained by binarizing and decoding the signal obtained in this way by a tracking slice circuit. At this time, since the error detection information is added to the identification information, it is determined whether or not the error has been correctly detected, and only the correct one of the plurality of pieces of identification information can be used.

The detection of the wobble signal is performed in the same manner. That is, since the positional relationship between the light spot and the groove is modulated by the wobble, a signal output 41 as shown in FIG. 8 is obtained. However, wobble amplitude (track displacement: 20 nm)
Is smaller than the displacement amount of the identification information (about 0.3 μm), so that the amplitude of the wobble signal is correspondingly smaller.

Next, an example of a method for obtaining a timing signal (clock signal) from the wobble signal detected in this way is shown in FIG. First, the reproduced signal of FIG.
The amplitude of the identification information section is limited by passing through the limiter circuit of FIG. Next, only the signal of the component synchronized with the wobble signal is extracted using the band pass filter of FIG. Next, binarization is performed by a comparator shown in FIG. 10C, and finally, a phase comparator, a filter circuit,
A clock signal is obtained using a VCO (Voltage Controlled Oscillator) and a phase locked oscillator (PLL) having a period of 186 minutes. At this time, the characteristics of the filter used for the PLL include:
In this example, the wobble signal is set so as to be sufficiently lower than the frequency corresponding to the 11.2 wobble cycle so as not to be affected by a missing portion (identification information section) of the wobble signal. In this embodiment, since the frequency of the wobble is about 160 kHz, the frequency band of the PLL is set to about 2 kHz. This frequency corresponds to the frequency corresponding to the length of the recording unit (about 700
(Hz) is desirable from the viewpoint of speeding up access.

Thus, a clock signal synchronized with the wobble signal was obtained. A method for recording and reproducing information using the clock signal and the identification information will be described below. FIG. 9 shows a timing chart of recording and reproduction. (A), (b), (c), and (d) are an identification information detection signal, a wobble signal, a clock signal, and a recording / reproducing timing signal. The identification information detection signal is a signal indicating that the identification information has been normally detected. Normally, a recording unit area to be recorded / reproduced is identified based on this signal, and the timing of recording and reproduction is controlled. In the present invention, when the identification information cannot be normally detected as shown in FIG. 9 (in the figure, the mark “x” indicates that the identification information could not be detected), the last normally detected identification information is used as a reference. The recording / reproduction timing signal is obtained by counting the clock signal obtained from the wobble signal and substituting the identification information detection signal. In this way, even when the identification information cannot be detected normally, a recording / reproducing timing signal can be obtained. Since this signal is generated from a wobble signal synchronized with the recording medium, the rotation speed of the medium is reduced. Even if there is an error such as, it is obtained accurately,
Even when a plurality of pieces of identification information cannot be detected consecutively, there is no possibility that errors are accumulated. For this reason, it is possible to construct a recording / reproducing apparatus that allows a great deal of errors in the identification information itself.

As described above, by combining the signal detected from the wobble with the identification information, the position of the light spot can be identified at every position on the disk, so that the reliability of the recording / reproduction is improved. By utilizing this fact, the reliability of recording / reproduction can be ensured without performing any inspection on the recording medium at the time of shipping the medium, thereby greatly reducing the cost of the recording medium. It becomes possible. In addition, it is extremely resistant to dirt, so that it is not necessary to protect it by putting it in a case or the like. For this reason, it becomes possible to provide a low-cost medium.

According to the above embodiment, the reliability of recording / reproducing is greatly improved. For example, the reliability of recording / reproducing can be ensured without inspecting the recording medium at the time of shipping the medium. The cost of the medium can be significantly reduced.
In addition, it is extremely resistant to dirt, so that it is not necessary to protect it by putting it in a case or the like. For this reason, a low-cost medium can be provided.

Further, by arranging the recording units radially in the radial direction, access between tracks is facilitated and crosstalk between positional information of each recording unit is minimized. In addition, by arranging the recording units such that the lengths of the arcs are substantially the same, the recording density becomes substantially uniform in the disk, and the entire surface of the disk can be used efficiently.

Further, the start point and the end point of the recording unit can be reliably detected by using the oscillation cycle, and the accurate position in the recording unit can be detected. In addition, since the length of the recording unit and the oscillation period are completely synchronized, the rotation speed of the recording medium is automatically controlled by controlling the oscillation frequency to be constant, and the relative speed of the recording medium is substantially constant. Can be controlled so that Further, since it is easy to make the length of each recording unit on the recording medium constant, the length of an extra gap on the recording medium can be minimized. Furthermore, since recording / reproduction can be performed while monitoring the track deviation amount, the reliability of the positioning servo is dramatically improved.

[0066]

According to the present invention, the identification information is provided for each recording unit, and the position information is reliably obtained even in the recording portion by the swing of the groove portion and the inter-groove portion as the recording portion. The recorded information can be accessed, and accurate positioning of the recorded information becomes possible.

[Brief description of the drawings]

FIG. 1 is a plan view showing a track arrangement of an embodiment of an information recording medium of the present invention.

FIG. 2 is a plan view showing an arrangement of identification information in one embodiment of the information recording medium of the present invention.

FIG. 3 is a plan view showing an arrangement of identification information of a track connecting portion in one embodiment of the information recording medium of the present invention.

FIG. 4 is a partially enlarged perspective view of the information recording medium of the present invention.

FIG. 5 is a plan view showing group division of an embodiment of the information recording medium of the present invention.

FIG. 6 is a plan view showing an example of numbering of identification information of an embodiment of the information recording medium of the present invention.

FIG. 7 is a block diagram showing an example of a recording / reproducing apparatus using the information recording medium of the present invention.

FIG. 8 is a waveform chart showing an example of a reproduced signal obtained from the information recording medium of the present invention.

FIG. 9 is a waveform chart showing an example of a signal used for recording and reproduction on the information recording medium of the present invention.

FIG. 10 is an explanatory diagram showing an example of a recording / reproducing method using the information recording medium of the present invention.

[Explanation of symbols]

1 recording unit, 2 identification information, 3 groove portion, 4 groove portion,
5: track switching unit, 6: non-switching unit, 7: light spot, 15: swing, 16: one cycle of swing, 21: first
, Identification information arranged at the second position, 23 pits, 11, 12 recording units, 81, 82 information recording unit.

──────────────────────────────────────────────────続 き Continued on the front page (72) Motoyuki Suzuki, Inventor 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture, Hitachi, Ltd. Video Information Media Division (72) Inventor Nobuhiro Tokujuku Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa 292 Hitachi, Ltd. Video Information Media Division (72) Inventor Kuki Sugiyama 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd.Video Information Media Division (72) Inventor Hiroyuki Minemura Yokohama, Kanagawa Prefecture 292 Yoshida-cho, Totsuka-ku, Hitachi, Ltd.Video Information Media Division (72) Inventor Tetsuya Fushimi 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd.Video Information Media Division (56) References JP Hei 7-210873 (JP, A) A) Patent 2856390 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B ^7/ 00-7/013 G11B 7/24

Claims (1)

(57) [Claims] 1. An information recording medium having a concentric or spiral groove structure along a track, wherein the groove structure swings in a radial direction of the information recording medium, and the track has a radial boundary. One zone is composed of at least two recording units which are divided into a plurality of recording units in a track direction and which are radially adjacent to the information recording medium among the recording units divided at the radial boundary,
The oscillation period of the groove structure included in each recording unit in the one zone is substantially the same, and each recording unit is provided with the groove and the portion where the oscillation is interrupted. the length Ri integral multiple der of the period of the oscillating, the broken portion is of the groove structure to the interrupted portion
When swinging is compensated for, recording units adjacent in the circumferential direction
Is configured so that the swing phases are connected continuously.
Information recording medium, characterized in that there.