JP2004171773A - Information storage medium, information reproducing method, and information reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the performance and to reduce the manufacturing cost in an information storage medium provided with a plurality of information storage layer in one disk type information storage medium, an information reproducing method and an information reproducing device reproducing data for every sector unit using the information storage medium. <P>SOLUTION: This optical disk has recording layers of at least first layer and second layer in which one side is arranged above the other side so that information recorded in respective layers can be read out optically from one side of the disk. Tracks are formed on the second recording layers of the first layer and the second layer, and a plurality of sectors are provided along the tracks. Tracks of the first layer and the second layer are spiral type, the tracks are arranged so that a winding direction of the spiral pattern of the first layer and the second layer are inverse direction each other when they are seen from the same side of the disk. An address of a sector provided at the recording layer of the first layer is increased from the most inner periphery to the most outer periphery, and an address of a sector provided at the recording layer of the second layer is increased from the most outer periphery to the most inner periphery. Sector addresses of the first layer and the second layer arranged at almost corresponding positions in the radial direction of the disk have complementary relation. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to an information storage medium having a plurality of information storage layers on a single disc-shaped information storage medium, and an information reproducing method and an information reproducing apparatus for reproducing data in sector units using the information storage medium. .

  A conventional optical disk medium has only one recording layer, and an optical disk having a plurality of recording layers has not been considered. However, a magnetic storage medium usually has a plurality of recording layers on each magnetic disk. FIG. 9 shows the structure of such a magnetic storage medium. Usually, a magnetic disk is provided with a plurality of disk-shaped magnetic storage media D1 and D2, and magnetic heads M1, M2, M3 and M4 for reading and writing on four recording surfaces, respectively. These read / write magnetic heads M1, M2, M3, M4 are respectively provided at one ends of swing arms A1, A2, A3, A4 which are simultaneously rotated by a pulse motor. Thus, the read / write recording surface can be switched simply by selecting an appropriate magnetic head. A number of concentric tracks are formed on each recording surface, and each track is divided into a number of sectors. Each of these sectors generally has a capacity of 512 bytes to 2048 bytes, and is used as a unit for recording information. At the head of the sector, an address consisting of a track number and a sector number is written. The magnetic disk drive positions the head based on the address information. Track numbers are assigned in ascending order from the outer circumference to the inner circumference.

However, in the conventional optical disk medium, a spiral groove, not a concentric circle, is formed as a track. For example, the track number and sector number of an optical disc medium (for example, a 90 mm magneto-optical disc conforming to the ISO 10090 standard) specified for information processing are the same as those of a magnetic disc except that the track shape is spiral. Assigned.
The address of each sector in an optical disk medium which was first developed for audio recording and later diverted for information processing, that is, a CD-ROM, is expressed using minutes, seconds, and frames.

  The recording density of a CD-ROM or the like is constant over the entire surface of the disk in order to maximize the disk storage capacity. Further, in order to keep the amount of information reproduced per unit time constant, the disk is rotated by a CLV (constant gland velocity) method. In the CLV method, the disk is rotated at a variable speed corresponding to the radial position on the disk so that the beam spot converged on the disk by the optical head scans a fixed distance on the disk per unit time. Further, a disk having a constant recording density over the entire surface of the disk is also known as a CLV type disk.

FIG. 10 shows a sector arrangement of a CLV type disk. In FIG. 10, the fan-shaped small pieces are sectors. Each sector is spirally connected. Since the recording density is constant, the size (capacity) of each sector is the same from the inner circumference to the outer circumference.
FIG. 11 shows the internal structure of a sector. Each sector has a header portion with an address for uniquely identifying the sector, a data portion in which user data is recorded, and an ECC (error correction code) in which a code used to correct an error during reproduction is recorded. Correction code) block.

In recent years, the moving image compression technology has advanced, and it has become possible to store a high-quality moving image equivalent to that of a movie theater on a single optical disk. Such a disc is known as a DVD (Digital Video Disc).
A DVD can store about 135 minutes of high-quality moving images on a single sheet. However, not all video sources are about 135 minutes. Therefore, it has been proposed to double the capacity by forming two recording layers on one optical disc. FIG. 12 shows the principle of reproducing data from an optical disk having two recording layers, which will be described below.

  When forming each recording layer, a pit row and a land row are formed on a transparent substrate, and aluminum is deposited thereon. A transparent photocurable resin is injected between the first recording layer and the second recording layer. The thickness of the aluminum on the first recording layer is adjusted so that half of the incident light is reflected and half is transmitted. The thickness of the aluminum on the second recording layer is adjusted to reflect all of the incident light. By moving the objective lens that converges the laser light closer to or farther from the optical disc, the beam spot (focal point) of the laser light can be converged on the aluminum of the first or second recording layer.

  Here, each recording layer of the DVD medium will be described below. Like a conventional optical disk and magnetic disk, a DVD medium records information by dividing the information into sector units. The sector arrangement of each recording layer of the DVD medium is similar to the sector arrangement of the CLV type disk shown in FIG. The structure of each sector is the same as that of the conventional information storage medium, and has the sector structure shown in FIG.

  FIGS. 13A, 13B, 13C, and 13D show the spiral groove, the rotational speed, and the reproduction direction of the conventional information storage medium having the two recording layers described above. 13A shows the spiral groove pattern of the first recording layer, FIG. 13B shows the spiral groove pattern of the second recording layer, FIG. 13C shows the rotation speed of the disk, and FIG. 13D shows the reproduction of the disk. Indicates the direction. As shown in FIG. 13D, user data is recorded in the data blocks of the first and second recording layers. In order to confirm the current position even when the head overruns from the data block, the address of the sector is also recorded in the leading area and the leading area (shown by hatching in FIG. 13D).

When the information storage medium is rotated clockwise, both the first and second recording layers are reproduced from the inner periphery to the outer periphery. Also, the rotation speed of the information storage medium is inversely proportional to the radius, and therefore, decreases as the head moves from the inner circumference to the outer circumference. In order to continue reproduction from the first layer to the second layer of the recording layer, it is necessary to move the head from the outer periphery to the inner periphery and adjust the rotation speed of the medium in parallel with the movement.
In the case of an information storage medium having two or more recording layers, there are two things that need to be considered when addressing sectors. First, it is desirable that every address be unique in the information storage medium. If the same address exists in both the first recording layer and the second recording layer, the desired information is recorded in either the first recording layer or the second recording layer by using only the address. The inconvenience of not knowing arises. Second, it is desirable that addresses assigned to the respective layers can be easily converted to addresses of the first layer. The reason is that the address is position information, and when moving to a target sector, the moving distance must be calculated based on the address. In particular, in the information storage medium of the CLV system, the number of sectors per one round of the disk is proportional to the radius at which the sector is located, and the number of sectors counted from the center of the disk is proportional to the area up to the radius at which the sector is located. In other words, the number of grooves and the address of each sector counted from the center of the disk have a square root relationship.

  An apparatus that reproduces a CLV-type disc must calculate the square root in order to determine the number of grooves to be traversed necessary to position a head at a target sector. If it is difficult to convert the address of each layer to the address of the first layer, a different square root must be calculated for each layer.

  Generally, in the standard of an optical disk medium, a center value and a deviation are defined with respect to a groove interval and a radius of an innermost groove. Therefore, if the address located at the innermost periphery is indefinite with respect to the radius of the innermost peripheral groove, the above-described calculation for obtaining the square root increases indefinite terms. As described above, when the address located at the innermost circumference of each layer is indefinite, the time and the table required for obtaining the square root increase. As a result, an apparatus for reproducing such a disc results in an increase in the cost of the table required for obtaining the square root and an increase in the processing time required for obtaining the square root.

  Conventionally, an optical disk having a plurality of recording layers has been proposed in order to increase the recording capacity per storage medium. As with magnetic disks, such optical disks utilize both sides of the information storage medium. One example is disclosed in Japanese Patent Application Laid-Open No. Hei 2-103732. The cited document discloses that the spiral track on the first side and the spiral track on the second side are reversed in order to enable smooth continuous playback from the first side to the second side. ing.

  However, the recording surfaces of the conventional double recording layer type optical disks are all opposite, and the reflectances of both surfaces are the same. Therefore, one optical head is provided on each side, and one optical head is provided in the reproducing apparatus in total. An optical head is an expensive device because it generally includes a semiconductor laser generator suitable for a light source, an optical device for adjusting the intensity of light, and an electromagnetic coil generator for adjusting a focal point. Therefore, the reproducing device used in connection with the conventional optical disk of the double recording layer type is ultimately a very expensive device.

Since there are two separate optical heads for the first and second sides of the optical disc, the first optical head for the first side surface is on the outermost track and the second side is A second optical head for the surface may be on the innermost track. Also, due to recent technical development called jitter-free reproduction technology, it is possible to reproduce correctly even when the rotation speed of the disk deviates from an appropriate speed. Therefore, in order to perform smooth continuous reproduction from the first side to the second side, the first head is moved from the inner periphery to the outer periphery, and then the second head is moved from the outer periphery to the inner periphery, or vice versa. That is, the use of a reproducing apparatus that moves the first head from the outer circumference to the inner circumference, and then moves the second head from the inner circumference to the outer circumference. There are no restrictions. The first head may play from the inner circumference to the outer circumference, and then the second head may play from the inner circumference to the outer circumference.
Further, in the conventional dual recording layer type optical disk, two individual heads were required, so that the same address could be used on the first side and the second side.

JP-A-2-103732

As can be seen from the above, in the conventional double recording layer type optical disk, it has been considered that smooth continuous reproduction from the first side to the second side can be realized using only one optical head. I never did. In a conventional double recording layer type optical disk, a plurality of optical heads are provided from the first side to the second side in order to realize smooth and continuous reproduction. Alternatively, as one of the solutions, the head is moved instantaneously from the inner circumference to the outer circumference or vice versa, and at the same time, the rotation speed of the disk is changed. However, from a practical point of view, such a device cannot be realized.
As described above, a problem of the conventional information storage medium is that the grooves are formed and the addresses are assigned without considering the continuous reproduction over a plurality of recording layers. As a result, the performance of an apparatus for reproducing such an information storage medium is reduced and the cost is increased.

In order to solve the above-mentioned problem, the present invention provides an information storage medium having a plurality of recording layers, and in which odd-numbered layers and even-numbered layers have spiral playback directions opposite to each other. Further, in the sectors on the odd-numbered layers and the sectors on the even-numbered layers located at the same radius, the addresses assigned to the respective sectors have a complement relation.
An information reproducing method for reproducing data in units of sectors from an information storage medium having a plurality of recording layers includes a spiral direction recognition step for recognizing a spiral moving direction of each layer, and a sector on an odd-numbered layer located at the same radius. An address conversion step of providing a continuous logical space over a plurality of layers to an information storage medium to which a number having a complement relation is assigned as an address of a sector on an even-numbered layer, and an access distance to a specific address Is calculated.

  The information reproducing apparatus of the present invention for reproducing data in sector units from an information storage medium having a plurality of recording layers includes a spiral direction recognizing means for recognizing a spiral moving direction of each layer and an odd-numbered layer located at the same radius. Address conversion means for providing a continuous logical space over a plurality of layers to an information storage medium to which a number having a complement relation is assigned as an address of a sector on an even-numbered layer and a sector on an even-numbered layer; Moving distance calculating means for obtaining an access distance.

According to one aspect of the present invention, an optical disc comprises:
One or more recording layers, one of which is disposed above the other, so that information recorded on each layer can be optically read from one side of the disc;
A track formed on the first and second recording layers and provided with a plurality of sectors, wherein the tracks on the first and second layers are spiral and have the same shape as the disk. And tracks arranged so that the winding directions of the spiral patterns of the first layer and the second layer are opposite when viewed from the side.

According to another aspect of the present invention, an optical disc comprises:
One or more recording layers, one of which is disposed above the other, so that information recorded on each layer can be optically read from one side of the disc;
A track formed on the first and second recording layers and provided with a plurality of sectors;
The addresses of the sectors given to the sectors, and the addresses of the sectors on the first recording layer increase from one circumferential side to the other circumferential side, and the one circumferential side is the innermost. The other peripheral side is the other innermost or outermost peripheral side, and the address of the sector on the second recording layer is the other peripheral side. And the address of the sector increasing from the side toward the one peripheral side,
The addresses of the sectors on the one layer and the addresses of the sectors on the other layer, which are allocated to the sectors of the track substantially corresponding to each other, have a complement relation.

According to still another aspect of the present invention, in an optical disc reproducing method for reproducing an optical disc,
The optical disk is
One or more recording layers, one of which is disposed above the other, so that information recorded on each layer can be optically read from one side of the disc;
A track formed on the first and second recording layers and provided with a plurality of sectors;
The address of the sector given to the sector, and the address of the sector on the first recording layer increases from one circumferential side to the other circumferential side, and the one circumferential side is the innermost. The other circumferential side is the other inner circumferential side or the outermost circumferential side, and the address of the sector on the second recording layer is the other circumferential side. And the address of the sector increasing from the side toward the one peripheral side.
The addresses of the sectors on the one layer and the addresses of the sectors on the other layer, which are allocated to the sectors of the track that substantially correspond to each other, have a complement relation,
The method comprises:
Detecting the ascending direction of the address of the sector on the optical disc;
Moving the optical head device to a target position on the layer;
Playing the disc in the direction detected by the detecting step.

According to still another aspect of the present invention, in an optical disc reproducing method for reproducing an optical disc,
The optical disk is
One or more recording layers, one of which is disposed above the other, so that information recorded on each layer can be optically read from one side of the disc;
A track formed on the first and second recording layers and provided with a plurality of sectors;
The address of the sector given to the sector, and the address of the sector on the first recording layer increases from one circumferential side to the other circumferential side, and the one circumferential side is the innermost. The other circumferential side is the other inner circumferential side or the outermost circumferential side, and the address of the sector on the second recording layer is the other circumferential side. And the address of the sector increasing from the side toward the one peripheral side.
The addresses of the sectors on the one layer and the addresses of the sectors on the other layer, which are allocated to the sectors of the track that substantially correspond to each other, have a complement relation,
The method comprises:
Detecting the address of the current sector on which the optical head device is focused;
Detecting the number of the recording layer on which the optical device is focused;
Converting the detected address into a continuous logical space that is shared with the address of the first recording layer when the detected recording layer number is the second recording layer number.

According to still another aspect of the present invention, in an optical disc reproducing apparatus for reproducing an optical disc,
The optical disk is
One or more recording layers, one of which is disposed above the other, so that information recorded on each layer can be optically read from one side of the disc;
A track formed on the first and second recording layers and provided with a plurality of sectors;
The address of the sector given to the sector, and the address of the sector on the first recording layer increases from one circumferential side to the other circumferential side, and the one circumferential side is the innermost. The other circumferential side is the other inner circumferential side or the outermost circumferential side, and the address of the sector on the second recording layer is the other circumferential side. And the address of the sector increasing from the side toward the one peripheral side.
The addresses of the sectors on the one layer and the addresses of the sectors on the other layer, which are allocated to the sectors of the track that substantially correspond to each other, have a complement relation,
The device comprises:
Means for detecting the ascending direction of the address of the sector on the optical disc;
Means for moving the optical head device to a target position on the layer;
Means for playing the disc in the direction detected by the detecting step.

According to yet another aspect of the present invention, there is provided an optical disc reproducing apparatus for reproducing an optical disc,
The optical disk is
One or more recording layers, one of which is disposed above the other, so that information recorded on each layer can be optically read from one side of the disc;
A track formed on the first and second recording layers and provided with a plurality of sectors;
The address of the sector given to the sector, and the address of the sector on the first recording layer increases from one circumferential side to the other circumferential side, and the one circumferential side is the innermost. The other circumferential side is the other inner circumferential side or the outermost circumferential side, and the address of the sector on the second recording layer is the other circumferential side. And the address of the sector increasing from the side toward the one peripheral side.
The addresses of the sectors on the one layer and the addresses of the sectors on the other layer, which are allocated to the sectors of the track that substantially correspond to each other, have a complement relation,
The device comprises:
Means for detecting the address of the current sector to which the optical head device is focused;
Means for detecting the number of the recording layer on which the optical device is focused;
Means for converting the detected address to a continuous logical space shared with the address of the first recording layer when the detected recording layer number is the second recording layer number.

By means of the above configuration, it is possible to provide an information storage medium capable of continuously reproducing information over a plurality of recording layers. In each recording layer of the information storage medium having a plurality of recording layers, the address of each sector on the n-th layer (n ≧ 2) is a complement of the address given to the sector having the same radial position in the first layer. Given from logical operations including operations. Therefore, in a continuous data reproduction operation in units of sectors over a plurality of recording layers, data is reproduced in an order in which the sector numbers increase in ascending order.
Further, if the reproducing direction of the spiral recording pattern on the information storage medium having a plurality of recording layers can be recognized, an information reproducing apparatus can be provided. When the reproducing direction of the spiral recording pattern is different for each recording layer of the information storage medium, the information reproducing apparatus can also generate a continuous logical space over a plurality of recording layers.

As a result, an information reproducing apparatus capable of continuously reproducing data over a plurality of recording layers can be provided at low cost and with high performance.
Embodiments of an information storage medium according to the present invention will be described below with reference to the drawings. FIGS. The figure shows a groove, a rotation speed, and a reproduction direction. The optical disc according to the first embodiment of the present invention includes first and second recording layers L1 and L2. 1A shows the spiral groove shape of the first layer L1, FIG. 1B shows the spiral groove shape of the second layer L2, FIG. 1C shows the rotation speed of the medium, and FIG. 1D shows the reproducing direction. As shown in FIG. 1D, user data is recorded in the data blocks of the first layer L1 and the second layer L2. On the other hand, as shown in FIG. 13D, a sector address is also recorded in the leading area 1a and the leading area 1b so that the current position can be confirmed even when the head overruns from the data area.

  A first feature of the present invention is that the sector address X on the first layer L1 and the sector address X 'on the second layer L2 are in a complementary relationship with each other. Ideally, sector addresses X and X 'face each other, but for the purposes of the present invention, sector addresses X and X' are on the same orbiting track, counting from the innermost track, or such. It only has to be near the truck.

  The first advantage is that a continuous logical space is obtained at the address of the outermost (or innermost) sector of the first layer and that of the second layer, which will be described with reference to FIG. 7A. explain in detail.

The second advantage is that the change rate of the address of the sector on the first layer and that on the second layer are symmetrical with respect to the disk. This will be described in detail with reference to FIG.
When the information storage medium is rotated clockwise, the first recording layer L1 is reproduced from the inner periphery to the outer periphery. By using the constant gland velocity (CLV) drive control, the rotation speed of the information storage medium is inversely proportional to the radius as shown in FIG. 1C. Accordingly, when the head is positioned at a given radial position on the disk, the rotation speed is the same for both the first layer L1 and the second layer L2.

As shown in FIG. 1D, when switching the reproduction from the first layer L1 to the second layer L2, there is no need to change the rotation direction of the disc when switching from the first layer to the second layer, and the head is moved from the outer periphery to the inner periphery. You don't have to.
FIG. 2 shows a reproduction direction of an information storage medium having four recording layers L1, L2, L3, and L4. In this embodiment, the first layer L1 and the third layer L3 are reproduced from the inner periphery to the outer periphery, and the second layer L2 and the fourth layer L4 are reproduced from the outer periphery to the inner periphery. Similarly to the switching of the recording layer between the first layer and the second layer, when the second layer and the third layer of the recording layer are switched or the third layer and the fourth layer of the recording layer are switched, the rotation direction of the disc is changed. There is no need to change or move the head.

When the present invention is applied to a digital video disk medium for recording moving images, a delay due to layer switching leads to interruption of an image, so that the substantial effect of this switching method is considerably large.
As described above, in the first embodiment of the present invention, it is possible to provide an information storage medium capable of continuously reproducing information over a plurality of recording layers.
However, if the conventional information recording medium is addressed to the information recording medium in which the recording grooves are formed so that the information can be continuously reproduced from the first layer to the second layer, the first layer becomes an address. Are reproduced in ascending order, and the second layer is reproduced in descending order of addresses. Taking the minutes, seconds, and frames that are the addressing of the audio CD as an example, the minutes, seconds, and frames decrease in the second recording layer as the music piece progresses.

  Further, when the first sector of the second layer is reproduced after the last sector of the first layer, the address of the outermost sector of the first layer is set as the address of the outermost sector of the second layer. Then, the address of any sector in the second layer is not uniquely determined. For example, if the address of the outermost sector on the first layer is X, the address of the sector at the same radial position on the second layer is X + 1, and all the sectors on the second layer depend on X. Incidentally, the address of the outermost sector of the audio CD is not fixed.

  A second feature of the present invention is that the disc has a plurality of recording layers, and the reproducing direction is opposite between the even-numbered layer and the radix-th layer. Therefore, according to the present invention, when the tracks are provided spirally as shown in FIG. 10, the spiral patterns of the first layer L1 and the second layer L2 are viewed from the laser beam source side as shown in FIG. Sometimes it is wound in the opposite direction. The spiral pattern in FIG. 10 is called counterclockwise winding. Accordingly, when the disc is viewed from the objective lens shown in FIG. 12, the first layer L1 is wound counterclockwise and the second layer L2 is wound clockwise. 1A and 1B also illustrate this.

  According to the present invention, the above arrangement can be realized by preparing two transparent layers each having a pattern similar to that described in FIG. The difference between the two layers is unique data recorded along a spiral track. For example, the surface of one layer having a track groove is mirror-finished, and the surface of the other layer having a track groove is semi-mirror finished, for example, by vapor deposition of an aluminum thin film. Next, as shown in FIG. 12, the two layers are faced with track grooves, and a photocurable resin TR is deposited and bonded between the surfaces. Thus, from the perspective of the disc, the spiral in one layer is counter-clockwise and the spiral in the other layer is clockwise. This arrangement has the following advantages.

The first advantage is that the reproduction direction of one layer goes from the inner track to the outer track, while the other layer goes from the outer track to the inner track, and vice versa. Therefore, the movement of the optical head when reproducing both layers requires only one reciprocation from the inner circumference to the outer circumference and from the outer circumference to the inner circumference.
Another advantage is that a cutting device for cutting a mold for forming a layer only needs to cut a mold in one spiral direction. As is clear from the above, the spiral winding directions of the first and second layers are the same when viewed from the grooved surface. Therefore, a cutting device for cutting a mold for forming a layer only needs to cut a mold in one spiral winding direction.

FIG. 3 shows a method of addressing an information storage medium having a two-layer structure according to the second embodiment of the present invention. In this embodiment, the address of the second-layer sector is the complement X ′ of the address X of the first-layer sector located at the same radius r (the prime symbol “′” indicates the complement). For example, if the arbitrary address of the first layer L1 is 030000h, the second layer sector located at the same radial position as this is FCFFFFh (where h is a hexadecimal number). This can be determined in the following four steps.
(1) 0 3 00 0 0 0 Hex (2) 0000 0011 0000 0000 0000 0000 0000 Binary (3) 1111 1100 1111 1111 1111 1111 Bit inversion (4) FCFFFFF Hexadecimal However, diagonal lines in FIG. The function of the part is the introduction part 1a and the derivation part 1b.

  The solid portion is a user data area between the introduction section 1a and the derivation section 1b of the first layer. In this embodiment, the address of the sector located at the innermost radius Rin of the first layer is Xin, Let Xout be the address of the sector located at the outer radius Rout. Here, Xin <Xout. The sector addresses of the first layer are assigned in ascending order from the inner periphery to the outer periphery, and the sector addresses of the second layer are assigned in ascending order from the outer periphery to the inner periphery by using the complement of the first layer. Can be Therefore, when the data of each sector is reproduced in the reproduction direction as shown in FIG. 1D, the sector addresses are assigned in ascending order from the first layer to the second layer as described later with reference to FIG. 7A. It is understood that it can be done.

In the case of an information storage medium having a four-layer structure, a bit indicating whether the address is the first reciprocation or the second reciprocation in the reproduction direction in FIG.
FIG. 4 shows a method of addressing an information storage medium having four layers L1, L2, L3, L4 according to the second embodiment of the present invention. According to this method, for example, the addresses of the sectors on the second, third, and fourth layers having the same radius as the sector having the address of 00300000h on the first layer are the addresses of 0FCFFFFh, 1030000h, and 1FCFFFFh, respectively. Granted.
Therefore, when the data of the sector written in the reproduction direction as shown in FIG. 2 is reproduced, the sector addresses are assigned in ascending order from the first layer to the fourth layer. As a result, the bits indicating the first and second round trips in the reproduction direction and the most significant bit (MSB) of the other addresses are 00b in the first layer, 01b in the second layer, 10b in the third layer, and 4b in the third layer. The layer number is 11b (here, b indicates a binary number). Therefore, by reading the above two bits, it is possible to identify which recording layer the sector is on.

  As described above, in the second embodiment of the present invention, in each recording layer of the information storage medium having a plurality of recording layers, the address of each sector on the nth layer Ln (n ≧ 2) is the first address. It is given from a logical operation including a complement operation for an address given to a sector having the same radial position in the layer. Therefore, data reproduced in a continuous sector unit over a plurality of recording layers is reproduced in ascending order of the sector number.

  FIG. 5 is a block diagram showing a configuration example of the information reproducing apparatus according to the third embodiment of the present invention. In FIG. 5, 1 is an optical disk, 2 is a disk motor, 3 is a lens, 4 is an actuator, 5 is a laser drive circuit, 6 is a photodetector, 7 is a transfer table, 8 is a preamplifier, 9 is a servo circuit, and 10 is two A digitizing circuit, 11 is a demodulation circuit, 12 is an error correction circuit, 13 is a CPU, 14 is a rotation detection signal, 15 is a disk motor drive signal, 16 is a laser drive signal, 17 is a light detection signal, 18 is a servo error signal, 19 is an actuator drive signal, 20 is a transfer table drive signal, 21 is an analog data signal, 22 is a binary data signal, 23 is a demodulation data signal, 24 is a correction data signal, and 25 is an internal bus. The lens 3, the actuator 4, the photodetector 6, the laser drive circuit 5, and the transfer table 7 constitute an optical head device.

  The CPU 13 controls the overall operation of the information reproducing apparatus via the internal bus 25 according to a built-in control program. The light reflected from the optical disk 1 becomes a light detection signal 17 by the light detector 6, and is added and subtracted by the preamplifier 8 to become a servo error signal 18 and an analog data signal 21. Further, the analog data signal 21 is subjected to A / D (analog / digital) conversion by the binarization circuit 10 to become a binarization data signal 22, and the binarization data signal 22 is then demodulated by the demodulation circuit 11. It becomes a demodulated data signal 23. Next, the demodulated data signal 23 becomes an error-free corrected data signal 24 by the error correction circuit 12. The servo error signal 18 is fed back to the actuator 4 as an actuator drive signal 19 by the servo circuit 9, and is used for focusing control and tracking control of the lens 3.

  In the case of a DVD-ROM drive used as a computer peripheral device such as a CD-ROM drive, a host interface circuit (not shown) is added, a correction data signal 24 is received from the error correction circuit 12, and a host interface such as SCSI is provided. Data is exchanged with a host computer (not shown) via a bus (not shown). In the case of a DVD player that operates as a consumer device such as a CD player, an AV decoder circuit (not shown) for expanding compressed moving images and audio is added, and the data is expanded after receiving a correction data signal 24 from the error correction circuit 12. Video and audio are output via a video terminal (not shown).

In the reproduction procedure of the information reproducing apparatus in the third embodiment of the present invention, the following three processes are performed in order to reproduce an information storage medium in which the addresses of the first and second layers have a complement relation in a two-layer structure. Will be needed.
(1) Recognize the reproducing direction of the spiral recording pattern of each layer.
(2) Convert a sector address into a continuous logical space over a plurality of layers.
(3) The moving distance of each layer to a desired address is obtained.
FIG. 6A is a flowchart used to explain a spiral direction recognizing means for recognizing a reproducing direction of a spiral recording pattern of each layer according to the third embodiment of the present invention. In this embodiment, the sector addresses are numbered in the order of reproduction, and it is assumed that the optical head is currently focused on the first layer.

In the first step 601 of the process, the current sector address X, that is, the current sector address is stored.
In step 602, the optical head is moved to the outer periphery by a predetermined amount.
In step 603, the current address of the sector address Y is stored.
In step 604, X and Y are compared. If X <Y, the process proceeds to step 605; otherwise, the process proceeds to step 606.
In step 605, the reproduction direction of the first layer is determined from the inner circumference to the outer circumference.
In step 606, the reproduction direction of the first layer is determined from the outer circumference to the inner circumference.
In step 607, the servo circuit 9 is instructed to change the focal position to the second layer.
At step 608, the current address of the sector address X is stored.
In step 609, the optical head is moved to the outer peripheral side by a predetermined amount.
At step 610, the current address of the sector address Y is stored.
In step 611, the address X and the address Y are compared. If X <Y, the process proceeds to step 612. If X <Y, the process proceeds to step 613.
In step 612, the reproduction direction of the first layer is determined from the inner circumference to the outer circumference.
In step 613, the reproduction direction of the first layer is determined in the same manner as from the outer circumference to the inner circumference.

  FIG. 6B is also a flowchart used to describe a modification of the spiral direction recognition means for recognizing the reproduction direction of the spiral recording pattern on each layer in the third embodiment of the present invention. In this embodiment, the spiral direction on a given layer is from the inner circumference to the outer circumference, and the MSB of the address of the layer is 0 according to the complement relation between the addresses of the layer. It is assumed that the focus position is the first layer. Similarly, when the spiral direction of a given layer is from the outer circumference to the inner circumference, the MSB of that layer is 1.

In the first step 621 of this processing, if the MSB is 0, the process proceeds to step 622, and if the MSB is 1, the process proceeds to step 623.
In step 622, the reproduction direction of the first layer is determined from the inner circumference to the outer circumference.
In step 623, similarly, the reproduction direction of the first layer is determined from the outer circumference to the inner circumference.
In step 624, the servo circuit 9 is instructed to change the focus position to the second layer.
In step 625, the MSB of the address of the current sector in the second layer is evaluated. If the MSB is 0, the process proceeds to step 626. If the MSB is 1, the process proceeds to step 627.
Therefore, in step 626, the reproduction direction of the second layer is determined from the inner circumference to the outer circumference.
Similarly, in step 627, the reproduction direction of the second layer is recognized from the outer circumference to the inner circumference.
As described above, according to the third embodiment of the present invention, it is possible to provide an information reproducing apparatus capable of recognizing a reproducing direction of a spiral recording path of an information storage medium having a plurality of recording layers.

  After the spiral winding direction is detected, that is, after the ascending order of the sector addresses is detected, the optical head is moved to the target position. Here, this target position is a calculated target position slightly different from the operator's desired target position. For example, the operator's desired target position is a sector at address 50,000h, but the calculated target position as the actual destination of the optical head is 4FFF6h, which is 10 sectors before the operator's desired target position. By detecting the spiral winding direction, it is possible to calculate the sector address not in front of the target position desired by the operator but in the front. The maximum retreat amount from the operator's desired target position is about one round of the track. Thereafter, when the optical head is moved to the calculated target position, reproduction is performed immediately before the operator-desired target position.

The present invention is not limited to the relationship between the MSB value of each sector address and the spiral movement direction of each layer described above. When the spiral movement direction is from the inner circumference to the outer circumference, the MSB is 1 and the spiral movement direction is It is obvious that the same effect can be realized even if the MSB is 0 when the distance is from the outer circumference to the inner circumference.
FIGS. 7A and 7B are flowcharts used to explain an address conversion means for providing a continuous logical space over a plurality of layers in the third embodiment of the present invention. In this example, as described above, when the spiral movement direction in the layer is from the inner circumference to the outer circumference, the MSB of the address on the layer is 0 due to the complement relation between the addresses on the layer, and conversely, the spiral movement When the direction is from the outer circumference to the inner circumference, the MSB of the address on that layer is 1.

  FIG. 7A is a flowchart for converting an address represented by a variable X on the information storage medium shown in FIG. 3 into a continuous logical space, that is, a continuous value represented by a variable N used by a host computer. Show. Here, the variable X represents an actual sector address written on the optical disk, and the variable N represents a converted sector address used by the host computer of the reproducing apparatus. In the following calculation, the constant Xin represents the address of the innermost sector, and the constant Xout 'represents the complement of Xout. The constant Xin is a number other than zero, but is set to a predetermined number such as 030000h. The constants Xout and Xin are stored in advance in the introduction section of the optical disc, and can be deleted by the apparatus when the disc is inserted.

In the first step 701, the address of the current sector where the optical head is currently located is read, and the address is set as a variable X.
In the next step 702, the MSB of the variable X is evaluated. If the MSB is 0, the process proceeds to step 704. If the MSB is 1, the process proceeds to step 703.
In step 703, (2 × Xout + 2) is added to the variable X. (Since −Xout ′ = Xout + 1, X × X−Xout ′ + Xout + 1 is the same as X × X + Xout + 1 + Xout + 1, so that the calculation can be simplified.)
In step 704, the difference value (variable X−Xin) is substituted for the variable N.

  The variable N obtained according to the flowchart of FIG. 7A is a continuous address starting from 0 in a plain region sandwiched between the hatched portions of the first and second layers. Therefore, the host computer can regard a disk having these two layers as a disk having one layer and double the capacity. In other words, the host computer recognizes the address of the outermost sector of the first layer and that of the second layer as a continuous number without a gap.

An example of such a calculation is shown below in detail for the addresses Xout and Xout 'of the outermost sector. First,
Xin = 030000h
and
Xout = 060000h
And
Since Xout 'is a complement of Xout, Xout' can be calculated by the following equation (1).
Xout '= 1000000h-1-060000h = F9FFFFh (1)
When the calculations are performed in steps 701, 702, and 704 to process the first-side address data, the following calculation (2) is performed in step 704. However, it is assumed that the current head position is at Xout.
N = Xout'-Xin-060000h-030000h = 030000h (2)
This indicates that the host computer recognizes that the address of the outermost sector on the first side of the disk is 030000h.

When the calculations are performed in steps 701, 702, and 704 to process the address data on the second side, the following calculation (3) is performed in step 704. However, it is assumed that the current head position is at Xout '.
N = Xout '+ (2 × Xout + 2) -Xin
= F9FFFFh + 060000h + 060000h + 2-030000h
= FFFFFFh + 060000h + 2-030000h
= 105FFFFh + 2-030000h
(The MSB of the first term overflows.)
= 060001h-030000h = 030001h (3)
This indicates that the host computer recognizes that the address of the outermost sector on the second side of the disk is 030001h. As described above, from the equations (2) and (3), in the computer, that is, in the continuous logical space, the addresses of the outermost sectors on the first side and the second side are recognized as continuous numbers. You can see that

FIG. 7A is a flowchart for converting a continuous logical space represented by N into a specific sector address represented by X of the information storage medium shown in FIG.
In step 711, the value of (N + Xin) is substituted for the variable X.
In step 712, the variable X is evaluated. If the variable X is larger than Xout, the process proceeds to step 712; otherwise, the process ends.
In step 713, the variable X is substituted for the difference value (X− (2 × Xout + 2)).
The variable X obtained according to the flowchart of FIG. 7B is a sector address of the information storage medium shown in FIG.
As described above, according to the third embodiment of the present invention, information capable of generating a continuous logical space over a plurality of recording layers on an information storage medium having different spiral reproduction directions every other layer. A playback device can be provided.

The present invention is not limited to the relationship between the MSB value of each sector address and the spiral movement direction of each layer described above. When the spiral movement direction is from the inner circumference to the outer circumference, the MSB is 1 and the spiral movement direction is It is obvious that the same effect can be realized even if the MSB is 0 when the distance is from the outer circumference to the inner circumference.
The relationship between addresses and groove positions in the CLV method will be described.
Since the groove width d is constant over the entire surface of the information storage medium, the relationship (Equation 1) below is established between the number of grooves T counted from the innermost circumference and the radius r in the first layer.
T = (r-Rin) / d (1)
Next, assuming that r is the radius and (X-Xin) is the address difference value between the address Xin on the inner circumference and the current address X, the recording density is constant over the entire surface of the information storage medium. In Equation (5), the area obtained from the right side of Equation (5) is equal to the area obtained from the left side.
(X-Xin) × s × d = π × (r × r-Rin × Rin) (5)
Here, s is the sector length, d is the groove width, and π is the pi. If the radius r is eliminated from the equations (4) and (5), the following relationship (Equation 3) holds in the first layer between the number T of grooves and the address X counted from the innermost circumference.
T = [{(y-Xin) × s × d ÷ π) + Rin × Rin} 1 / 2-Rin] ÷ d (6)

  Equation (5) is satisfied for the first and second layers when the change rate of the address of the sector on the first layer and that on the second layer are symmetrical with respect to the disk as shown in FIG. Only. In order to make the change rates of the sector addresses of the first layer and the second layer the same, it is necessary to select the sector addresses of the first layer and the second layer so that the sector addresses have a complement relation to each other.

  FIG. 8 is a flowchart showing a moving distance calculating means for obtaining a moving distance to a desired address in the third embodiment of the present invention. In this example, when the spiral movement direction in the layer is from the inner periphery to the outer periphery, the MSB of the address on the layer is 0, and when the spiral movement direction in the layer is from the outer periphery to the inner periphery, the MSB is It is assumed that the MSB of the address is 1. Further, it is assumed that the address of a desired sector to which the optical head is moved has been calculated as a variable z by the CPU 13.

In the first step 801 of this process, the MSB of the variable Z is evaluated. If the MSB is 0, the process proceeds to step 802, and if the MSB is 1, the process proceeds to step 803.
At step 802, the variable Z is substituted for the variable X.
In step 803, the complement of the variable Z is substituted for the variable X.
In step 804, the value T obtained based on the equation (6) is set as a target groove number W (the number of grooves counted from the innermost circumference).
At step 805, the address of the current sector is read out and set to a variable X.
In step 806, the MSB values of the variable X and the variable W are compared. If X and Z are equal, the process proceeds to step 811; otherwise, the process proceeds to step 807.
In step 807, if the MSB of the variable X is 0, the process proceeds to step 808. If the MSB is 1, the process proceeds to step 809.
In step 808, the servo circuit 9 is instructed to move the focus position to the second layer.
In step 809, the servo circuit 9 is instructed to move the focus position to the first layer.
At step 810, the address of the current sector is read out and set to a variable X.
In step 811, if the MSB of the variable X is 0, the process proceeds to step 813. If the MSB is 1, the process proceeds to step (812).
At step 812, the complement of X is substituted for the variable X.
In step 813, the value T obtained based on the equation (6) is set as the current groove number V.
In step 814, the following difference value (target groove number W)-(current groove number V) is added to the number of moving grooves U (the number of grooves that the magnetic head has to move).
Is assigned.

  Therefore, it is determined from the MSB of the address whether the destination is the first layer or the second layer, and if the destination is the second layer, the complement of the address is obtained. The number of grooves can be calculated for each layer. Methods such as Expression (6) including the square root include a method using a table, a method using an approximate expression, and a method using the Newton method. Regardless of which method is used, since the complement relation of addresses is used, the addresses of a plurality of layers can be obtained by using a common operation, whereby the program incorporated in the CPU 13 can be reduced in size and executed at high speed.

As described above, according to the third embodiment of the present invention, it is possible to provide an information reproducing apparatus capable of moving to a specific address on an information storage medium having different spiral reproducing directions every other layer.
The present invention is not limited to the above-described relationship between the MSB value of the address of each sector and the spiral movement direction in each layer. When the spiral movement direction is from the inner circumference to the outer circumference, the MSB is 1 and the spiral movement direction is It is clear that the same effect can be realized even when the MSB is 0 when the direction is from the outer circumference to the inner circumference.
As described above, it is possible to provide an information storage medium that can be continuously reproduced over a plurality of recording layers.

In each of the recording layers of the information storage medium having a plurality of recording layers, the address of each sector on the n-th layer Ln (n ≧ 2) is a complement operation with respect to the address of the sector having the same radial position on the first layer. From the logical operation that contains Therefore, in a continuous data reproduction operation in units of sectors over a plurality of recording layers, data is reproduced in an order in which the sector numbers increase in ascending order.
Further, an information reproducing apparatus capable of recognizing a spiral reproducing direction on an information storage medium having a plurality of recording layers can be provided. When the spiral reproduction direction is different for each recording layer of the information storage medium, the above-described information reproduction apparatus generates a continuous logical space over a plurality of recording layers and moves to a desired address on the information storage medium. It is also possible.

As a result, it is possible to provide an inexpensive and high-performance information reproducing apparatus that continuously reproduces data over a plurality of recording layers.
While the invention has been described above, it can be modified in various ways. Such modifications do not depart from the spirit and scope of the invention and any such modifications obvious to one skilled in the art are intended to be included within the scope of the following claims.

1A and 1B show spiral groove shapes of two recording layers according to the present invention, FIG. 1C is a graph showing rotation speed, and FIG. 1D is a recording layer according to a first embodiment of the present invention. FIG. 3 is a diagram showing a reproduction direction of an information storage medium having two of the following. FIG. 3 is a diagram illustrating a reproduction direction of an information storage medium having four recording layers according to the first embodiment of the present invention. FIG. 14 is a diagram illustrating addressing of an information storage medium having two recording layers according to a second embodiment of the present invention. FIG. 14 is a diagram illustrating addressing of an information storage medium having four recording layers according to a second embodiment of the present invention. It is a block diagram of an information reproducing device in a third example of the present invention. 13 is a flowchart illustrating a calculation for recognizing a spiral reproduction direction of each layer according to the third embodiment of the present invention. It is a flowchart which shows the changed aspect of the flowchart of FIG. 6A. 13 is a flowchart illustrating an operation of converting a detected address of a sector into a continuous logical space over a plurality of layers according to the fourth embodiment of the present invention. 11 is a flowchart illustrating an operation of converting a continuous logical space over a plurality of layers into an address of a sector according to a fourth embodiment of the present invention. 9 is a flowchart illustrating a calculation for calculating a moving distance of the optical head when moving from a current position to a target position. FIG. 11 is a diagram showing a magnetic disk having a plurality of recording surfaces in a conventional example. FIG. 3 is a plan view of a CLV (constant gland velocity) type disk. FIG. 2 is a diagram showing an internal sector structure of a disk. FIG. 3 is a diagram showing an optical disc having two recording layers. 13A and 13B show spiral grooves of two recording layers according to the prior art, FIG. 13C shows a rotational speed, and FIG. 13D shows an information storage medium having two recording layers according to the prior art. FIG. 3 is a diagram illustrating a reproduction direction.

Explanation of reference numerals

1: optical disk 2: disk motor 5: laser drive circuit 6: photodetector 7: transfer table 8: preamplifier 9: servo circuit 10: binarization circuit 11: demodulation circuit 12: error correction circuit

Claims (4)

An optical disc reproducing method for reproducing an optical disc, comprising:
The optical disc is
One or more recording layers, one of which is disposed above the other, so that information recorded on each layer can be optically read from one side of the disc;
A track formed on the first and second recording layers and provided with a plurality of sectors;
Addresses of the sectors given to the sectors, wherein the addresses of the sectors on the first recording layer increase from one peripheral side to the other peripheral side, and the one peripheral side is the innermost. The other peripheral side is the other inner peripheral side or the outermost peripheral side, and the address of the sector on the second recording layer is the other peripheral side. And the address of the sector increasing from the side toward the one peripheral side,
The addresses of the sectors on the one layer and the addresses of the sectors on the other layer, which are allocated to the sectors of the track that substantially correspond to each other, have a complement relation,
The method comprises:
Detecting the address of the current sector on which the optical head device is focused;
Detecting the number of the recording layer on which the optical head device is focused;
Converting the detected address into a continuous logical space shared with the address of the first recording layer, if the detected recording layer number is that of the second recording layer. Calculating a target sector address to which the optical head is moved;
Calculating the distance to move the optical head from the current sector address to the target sector address;
Moving the optical head based on the calculated distance. An optical disc reproducing device for reproducing an optical disc,
The optical disc is
One or more recording layers, one of which is disposed above the other, so that information recorded on each layer can be optically read from one side of the disc;
A track formed on the first and second recording layers and provided with a plurality of sectors;
Addresses of the sectors given to the sectors, wherein the addresses of the sectors on the first recording layer increase from one peripheral side to the other peripheral side, and the one peripheral side is the innermost. The other peripheral side is the other inner peripheral side or the outermost peripheral side, and the address of the sector on the second recording layer is the other peripheral side. And the address of the sector increasing from the side toward the one peripheral side,
The addresses of the sectors on the one layer and the addresses of the sectors on the other layer, which are allocated to the sectors of the track that substantially correspond to each other, have a complement relation,
The device comprises:
A device for detecting the address of the current sector to which the optical head device is focused;
A device for detecting the number of the recording layer on which the optical head device is focused;
An apparatus for converting the detected address to a continuous logical space shared with the address of the first recording layer when the detected recording layer number is that of the second layer. Means for calculating a target sector address to which the optical head is moved;
Means for calculating the distance to move the optical head from the current sector address to the target sector address;
4. The optical disc reproducing apparatus according to claim 3, further comprising: means for moving the optical head based on the calculated distance.

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