JP2002334448A - Multilayer disk memory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer disk memory whose layers can be distinguished at of recording/playing back if there is at least one stamper. SOLUTION: In the disk memory which consists of a plurality of layers, preformat areas including the address of each layer, etc., are shifted relative to each other in the disk rotating direction if the preformat areas are identical between the respective layers. Which layer is being currently accessed is recognized by detecting the amount of phase lags relative to a layer taken as a reference at recording/playing back.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer (three-dimensional) multi-layer disk memory having a recording / reproducing surface in order to dramatically increase the storage capacity. The present invention relates to a multi-layer disk memory capable of easily performing a judgment.

[0002]

2. Description of the Related Art FIG. 1 shows the basic structure of a multi-layer disk memory of this type. In FIG. 1, a disk D having a shape as shown in the right diagram is enlarged in the disk thickness direction for simplicity of explanation as shown in the left diagram.

In order to record / reproduce data to / from a target layer, an objective lens L is moved up and down. At this time, focusing control is performed based on a focusing error signal as shown in FIG. A laser beam B emitted from L is aimed at a target layer.

Now, an outline of a typical three-dimensional memory shown in US Pat. No. 6,009,065 will be described. This conventional technique uses incoherent fluorescent light as reflected light, unlike a CD or DVD reflective optical disk. This realizes multilayering.

In the conventional reflection type, a 650 nm laser irradiates the second layer in order to detect the information of the second layer.
The light is modulated and reflected by the pits or recording marks of the second layer, and the light travels toward the photodetector. At this time, if pits or marks are formed on the first layer, all light is not transmitted and some light is reflected, so that the amount of light reaching the photodetector is attenuated.

On the other hand, in the fluorescence type, when a 650 nm laser is applied to the second layer to detect information, fluorescence as incoherent light of 680 nm having a different wavelength is emitted from the second layer. This fluorescence goes to the detector method without being attenuated without being absorbed or reflected by the first layer.
In other words, each layer has a layer structure using a material that is not absorbed or reflected by light in the 680 nm band.

In the case of the fluorescent type, in the case of reproduction only, the pit portion in the layer shown in FIG. 3 is filled with a material that emits fluorescent light when irradiated with the light for forming the layer. Emits fluorescence. This allows information to be detected. In the case of recording, a recording mark is formed in the groove in FIG. 3 by a laser according to the recording information. Since this recording mark does not emit fluorescence even when irradiated with a laser at the time of reproduction, recorded information can be detected. In any case, the fluorescence is transmitted through the first layer, so that a large signal-to-noise ratio can be obtained as compared with the conventional reflection type.

A control signal from a servo control circuit for recording and reproducing information using this fluorescent disk is amplified by a servo amplifier, and a focusing and tracking actuator is driven to adjust the position of the objective lens. Laser light from a laser light source driven by a laser driver enters the objective lens.

A desired layer on the disk rotated by the spindle motor is irradiated with laser light by an objective lens, and reflected light by the laser light irradiation is taken in through the objective lens, and then guided to an optical filter. Only the laser light in the desired wavelength range is converted into an optical signal by the photodetector, amplified by the preamplifier, and taken into the controller 1 through the signal operation circuit.

[0010]

In recording / reproducing such a multi-layer disc, when accessing a target layer, it is necessary to be able to determine whether or not the accessed layer is a target address. For example, in an optical disc,
The focus position is controlled by accessing the target layer with the beam. However, in order to reach the target layer, it is not enough to count and access the focus error signal to obtain sufficient reliability. That is, there is a possibility that a counting error may occur due to some disturbance (electrical noise or the like) on the way.

If different preformats are created for each layer of the disc so that the layers can be identified, a stamper for each layer is required. When the number of stampers increases, it is necessary to manufacture a plurality of stampers, as well as to manage them.

US Pat. No. 6,009,065 is a reproduction-only three-dimensional memory. In the case of reproduction-only, a different stamper is manufactured for each layer, so that information indicating the layer number is entered for each layer. Is easy.

An object of the present invention is to provide a multi-layer disc memory capable of discriminating a disc layer at the time of recording / reproducing if there is at least one stamper.

[0014]

According to a first aspect of the present invention, in a disk memory having a plurality of layers, if the preformat including the address of each layer is the same between the layers, the arrangement of the preformat between the layers is changed. It is characterized in that it is shifted in the disk rotation direction.

According to a second aspect of the present invention, address information capable of identifying the layer is written only to the reference layer, and from the phase difference of each layer preformat from the reference layer, which layer is the current access layer is determined. It is determined whether there is. With such a configuration, each layer can be distinguished from each other even with a small number of stampers.

A third aspect of the present invention is characterized in that a detector for generating one pulse per rotation of the disk is provided for determining the position of each layer. With this detector, the speed of one rotation of the disk, that is, the time can be easily measured, and the phase difference between the pulse detected by this detector and the address position detected by the accessed layer can be immediately known. You can determine if you have accessed.

According to a fourth aspect of the present invention, a mark is provided on the disk so that the detector can generate one pulse per rotation. In this way, even if the disk on the turntable slides, there is no phase shift between the detector output and the address position in the disk, so that a highly reliable layer can be accessed. Also, by making the mark have a certain relationship with the address position in each layer, the correctness of the access can be immediately determined.

According to a fifth aspect of the present invention, the measurement of the phase relationship is performed at a fixed time interval, and the phase relationship between the detector output pulse and the arrangement of the disk preformat is detected. It is characterized by detecting slip from the initial position. By doing so, the correctness of the determination of each layer can be maintained.

According to a sixth aspect of the present invention, when data is recorded, data indicating which layer is present is recorded. By doing so, it is possible to confirm that the data of the correct layer is being reproduced, so that a highly reliable system can be realized.

According to a seventh aspect of the present invention, when overwriting is performed, data representing the layer is always recorded after confirmation. By doing so, double writing can be prevented. That is, overwriting to other layers can be avoided.

According to an eighth aspect of the present invention, at least one layer determination area is provided at a radial position on the inner circumference or the outer circumference in the disk surface. Accordingly, when exposing the master disk of the stamper in the CLV format in which the data recording density is constant at each radial position of the disk employed in the CD, the layer position can be determined by the above method based on the information indicating the layer position when the information area is formed. In such a case, the way of inserting the layer information becomes complicated, and the effect of the accumulated error of the layer position information (address) position can be ignored. By providing a separate layer position determination area on the inner circumference side or outer circumference side outside the data area, it becomes possible to freely select a format in which the layer determination is easy.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a multi-layer disk memory according to the present invention, in a disk memory having a plurality of layers, if the preformat including the address of each layer is the same between the layers, the preformat between the layers is the same. Are shifted from each other in the disk rotation direction. Then, as described in the claims, address information capable of identifying the layer is written only to the reference layer, and from the value of the phase difference from the reference layer, which layer is the current access layer is used. It is determined whether there is. Thus, each layer can be distinguished by a small number of stampers.

In the data area in each layer of the disk memory in the embodiment, as shown in FIG. 4, a CAV format is formed, sectors S are formed at regular intervals, and an address portion at the head of the sector S is formed. To
A sector number is recorded as address information. In the CAV format, the information amount of each track is the same, the number of sectors per track is the same, and the sector address portions are aligned in the disk radial direction. The track address indicating the track position of one round differs at the radial position, and the track address is assigned in order from the inner circumferential side or the outer circumferential side.

As shown in FIG. 5, a layer determination area A is set in a plurality of innermost tracks in these data areas, and a sector number is also entered at the head of a sector in the layer determination area A. . In the present invention, when each layer has the same preformat, the phase between each layer is shifted from each other in the disk rotation direction.

FIG. 6 shows the position of each sector address portion of each layer in, for example, an 11-layer disk. Only the sixth layer in the middle is the sixth layer immediately after each sector address part.
The format is such that layer address information indicating the layer is inserted and the layer is recognized as the sixth layer. The sector address positions of the other layers have predetermined phase differences with respect to the sector address positions of the sixth layer.

The first layer is (2π / 11) × 5, and the second layer is (2π / 11) × 5.
π / 11) × 4, the third layer is (2π / 11) × 3, the fourth layer is (2π / 11) × 2, the fifth layer is (2π / 11) × 1, and the seventh layer is (2π / 11). 11) × (−1), the eighth layer is (2π / 11) ×
(-2), the ninth layer is (2π / 11) × (-3), the tenth layer is (2π / 11) × (-4), and the eleventh layer is (2π / 11) ×
(-5).

For example, when accessing the first layer, a controller (not shown) (a component in a hardware mechanism of a device for recording / reproducing on a disk) first searches for a light beam in the layer direction (focus direction) and moves to the sixth layer. At this point, the layer address information indicating the sixth layer is detected, and it is recognized that the access has been correctly performed. Then, based on the disk rotation time information, the controller calculates the phase difference (2π / 2π / 2π / で) based on the time difference at which the sector address in the plane of the first layer and the corresponding sector address in the plane of the sixth layer are detected.
11) x5 can be determined. This allows the first
If the sector address when accessing the layer almost coincides with the time, it can be confirmed that the layer is the first layer. In this way, the target layer can be accurately accessed.

A plurality of tracks in the layer determination area are divided into a plurality of sectors, and a sector number is entered at the head of each sector. As described above, in the CAV format, the sector numbers in each track are arranged radially. By recognizing the phase difference with the same sector number of the sixth layer at the moment when the sector number of the layer determination area of each layer is recognized, it can be determined whether or not the access has been performed correctly. Since the determination is made based on the phase difference between the sender numbers, the determination can be made without waiting for one rotation of the disk at worst. The controller can measure the time of one rotation of the disk from data such as the innermost peripheral address of the sixth layer, and corrects the time difference measurement.

When the data area is in the CLV format, the same control as in the above-described CAV format cannot be performed because the sector addresses are not aligned in the disk radial direction. When the data area is in the CLV format, the above-described layer determination area is configured in the above-described CAV format, and the same control is performed to perform the layer determination. In the case of the write type, after the layer determination is performed, data indicating the layer is recorded in all the areas indicating the layer determination in each sector in the layer determination area. In the above embodiment, information indicating the sixth layer is already preformatted at the factory in the sixth layer layer determination area. This is formed by a stamper or written and manufactured in a factory. As described above, if the layer determination area is used, the number of the layer can be determined by accessing the layer determination area without accessing the sixth layer. When there is no data in the layer determination area, the target layer is accessed by the method described above.

The multi-layer disk memory according to the third aspect is characterized in that a detector for generating one pulse per rotation of the disk is provided to determine the position of each layer.

For example, the speed of one rotation of the disk, that is, the time, can be measured easily by using a detector which attaches a rotary encoder for detecting the absolute position to the disk rotating shaft and generates a signal which generates one pulse per rotation. The phase difference between the pulse detected in step (1) and the address position detected in the accessed layer can be known, and it can be determined whether the correct layer has been accessed.

First, the beam is scanned from the direction of incidence of the beam on the disk, and when the first focusing error signal comes out, the focus is pulled in and the focusing operation is performed in the first layer. Then, the tracking operation is started, the address position is detected, and the phase difference between the address position and the detection position of the output pulse by the detector is measured. If the phase difference between the address position of the first layer and the detection position of the output pulse is known, the phase difference between the address position in another layer and the detection position of the output pulse can be predicted. Then, it can be determined that the access has been correctly performed by comparing the output pulse with the address position information.

In the multi-layer disk memory according to the fourth aspect, a reference mark M made of a member for reflecting light is formed on the outermost periphery of the disk as shown in FIG. 7, and is rotated by a rotary motor as shown in FIG. The reference mark detector 2 including a light projecting element and a light receiving element for optically reading the reference mark M with respect to the multilayer disc D
Is provided. With this configuration, as shown in FIG. 9, each time the multilayer disc makes one revolution, the reference mark detector 2
Output one pulse.

In this way, even if the disk on the turntable slides, the phase of the detector output and the address position in the disk do not shift, so that a highly reliable layer can be accessed. Also, by making the mark have a certain relationship with the address position in each layer, the correctness of the access can be immediately determined. If this mark cannot be detected due to some cause (scratch, rubbing, etc.), if the mark can be executed by accessing the first layer and confirming the layer, the mark on the layer in the disc can be obtained. It can be accessed even if it cannot be detected. In this case, the access time becomes longer.

In FIG. 8, there is a type of optical pickup which irradiates a light spot by accessing a target address (layer address, track address and sector address) of the multilayer disc D. The controller 1 controls the rotation motor, controls the optical pickup to access a target address, transmits and receives recording / reproducing data to and from the optical pickup, detects a signal from the reference mark detector 2, interfaces with a personal computer, corrects errors, modulates and demodulates. It has functions such as signal processing such as synchronous processing.

In the multi-layer disc according to the fifth aspect, a slip from the initial position of the disc is detected by detecting a phase relationship between the detector output pulse and the arrangement of the disc preformat at a predetermined fixed time interval. It is characterized by doing. After detecting the slip, the phase relationship between the detector output pulse and the arrangement of the disc preformat is detected again to determine the layer. By doing so, the correctness of the determination of each layer can be maintained.

According to the sixth aspect of the present invention, when data is recorded, data indicating which layer is present is also recorded. As shown in FIG. 10, in each sector, a layer address storage section 3 is provided at the head of the data storage section, and a layer address indicating layer information is stored in the area. The address portion includes a pit row (emboss portion) in which a track number indicating which track is located and a sector number indicating which sector is located are formed using a stamper. This makes it possible to know where on the disk surface the light spot is illuminating. The gap is
When writing the layer address information in the layer address recording section after the controller in the drive device immediately recognizes the address section, in order to avoid overwriting due to rotation fluctuation of the disk, or to detect the layer address after detecting the address. It is provided to secure the data processing time until writing or the rotation delay time. The data recording section naturally includes user data, an error correction code for ensuring data reliability, management information, and the like. In the gap portion provided at the end of the sector, the recording data length of the data recording portion becomes longer due to disk rotation fluctuation, and overwriting to the next address portion is avoided. By doing so, it is possible to confirm that the data of the correct layer is being reproduced, so that a highly reliable system can be realized.

The multi-layer disc according to the seventh aspect is characterized in that when overwriting, data indicating the layer is always recorded after confirmation. By doing so, double writing can be prevented. That is, overwriting to other layers can be avoided.

The multilayer disc according to the eighth aspect is characterized in that at least one layer determination area is provided at a radial position on the inner peripheral side or the outer peripheral side in the disk surface.
By this, when exposing the master of the stamper in the CLV format, when inserting information indicating the layer position when forming the information area so that the layer position can be determined by the method described above,
The method of inserting layer information becomes complicated, and the effect of the accumulated error of the layer position information (address) position can be ignored. By providing a separate layer position determination area on the inner circumference side or outer circumference side outside the data area, it becomes possible to freely select a format in which the layer determination is easy. As shown in FIG. 6, only the layer determination area of each layer is configured in the CAV format, and the layers are overlapped by shifting the phase of the sector address of each layer. In this way, the drive device can execute the determination of each layer.

When an address is formed by pits, zone CAV is known as a method of recording a large amount of information on the disk surface using zone CAV. This method divides zones concentrically in the disk radial direction. The linear density of each zone is almost the same, and each zone has a CAV format. Therefore, the number of sectors per track in each zone is small on the inner circumference side and larger on the outer circumference side. In addition, when the address is formed by bits, the crosstalk at the time of reproducing the recorded mark by the address pit can be avoided by performing the operation in the zone CAV as in the case of the CAV, as compared with the case where the address is formed by the CLV. In order to determine the layer in this format, when configuring each layer, the disk is configured with a phase shift similar to the CAV format. In this format, when determining the layer while keeping the disk rotation speed constant,
The time of the sector interval of each zone is different. The controller can measure the time difference (phase difference) between the pulse from the reference mark detector 2 and the head of the sector, and determine the layer using the zone information. That is, the time until the head of the sector differs for each zone. This zone CAV
When changing the rotation speed of the disk for each zone in order to make the data recording / reproducing frequency for each zone constant in the format, the time interval between sectors becomes constant. In consideration of this, the controller can measure the time difference (phase difference) between the pulse from the reference mark detector 2 and the head of the sector to determine the layer.

[0041]

According to the first aspect of the present invention, in a disk memory having a plurality of layers, if the preformat including the address of each layer is the same between the layers, the arrangement of the preformat between the layers is changed. The layers are shifted in the rotation direction, and the layer currently being accessed is determined by detecting the phase difference in each layer.
Then, as described in claim 2, address information capable of identifying the layer is written only to the reference layer, and from the value of the phase difference from the reference layer, which layer is the current access layer is determined. It is possible to determine whether or not there are, and each layer can be distinguished with a small number of stampers.

According to the third aspect of the present invention, since a detector for generating one pulse per one rotation of the disk is provided, the speed of one rotation of the disk, that is, the time can be easily measured, and the pulse detected by this detector is accessed. The phase difference from the address position detected in the layer can be known, and it can be determined whether the correct layer has been accessed.

According to a fourth aspect of the present invention, the disk is marked so that the detector can generate one pulse per rotation. Therefore, even if the disk on the turntable slides, the output of the detector and the address in the disk are obtained. Since there is no phase shift from the position, it is possible to access a highly reliable layer. Also, by making the mark have a certain relationship with the address position in each layer, the correctness of the access can be immediately determined.

According to a fifth aspect of the present invention, the measurement of the phase relation is performed at a fixed time interval to detect the phase relation between the detector output pulse and the arrangement of the disk preformat. As a result, slip from the initial position of the disk is detected, so that the correctness of the determination of each layer can be maintained.

According to the sixth aspect of the present invention, when data is recorded, data indicating which layer is present is also recorded, so that it can be confirmed that the data of the correct layer is reproduced. A highly reliable system can be realized.

According to the seventh aspect of the present invention, when overwriting, the data representing the layer is always recorded after confirmation, so that double writing can be prevented. That is, overwriting to other layers can be avoided.

According to the eighth aspect of the present invention, at least one layer determination area is provided at a radial position on the inner peripheral side or the outer peripheral side in the disk surface, so that when exposing the master of the stamper in the CLV format, the information area is formed. Sometimes, when the information indicating the layer position is inserted so that the layer position can be determined by the above method, the method of inserting the layer information becomes complicated, and the layer position information is
The influence of the accumulated error of the (address) position can be ignored. By providing a separate layer position determination area on the inner circumference side or outer circumference side outside the data area, it becomes possible to freely select a format in which the layer determination is easy.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a multilayer disk memory

FIG. 2 is a diagram showing a focusing error signal obtained during focusing.

FIG. 3 is a diagram showing details of the internal structure of the multilayer disc;

FIG. 4 is a diagram showing a CAV format adopted for a multilayer disc memory;

FIG. 5 is a diagram showing a layer determination area formed in the multilayer disk memory;

FIG. 6 is a diagram showing a layout of a layer determination area of each layer.

FIG. 7 is a view showing a layer reference mark formed on the multilayer disk memory;

FIG. 8 is a diagram showing a mechanism for detecting a reference mark in FIG. 7;

FIG. 9 is a time chart showing the reference mark detection timing.

FIG. 10 is a configuration diagram of a recording area in which a layer address recording unit for layer determination is provided in each sector.

[Explanation of symbols]

 Reference Signs List 1 controller 2 fiducial mark detector 3 layer address recording section A layer determination area D multi-layer disc M fiducial mark S sector

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 20/10 311 G11B 20/10 311 321 321Z 20/12 20/12

Claims (8)

[Claims] 1. In a disk memory having a plurality of layers, when the preformat including the address of each layer is the same between the layers, the arrangement of the preformat between the layers is shifted from each other in the disk rotation direction. A multilayer disk memory characterized by the above-mentioned. 2. The multi-layer disk memory according to claim 1, wherein address information capable of identifying the layer is written only to a reference layer. 3. The multi-layer disk memory according to claim 1, further comprising a detector that generates one pulse per rotation of the disk. 4. The multi-layer disk memory according to claim 3, wherein the disk is marked so that the detector can generate one pulse per rotation. 5. The multi-layer disk according to claim 1, wherein a phase relationship between the detector output pulse and the arrangement of the disk preformat is detected at a predetermined time interval. memory. 6. The optical disk memory according to claim 1, wherein when recording data, data indicating which layer is present is also recorded. 7. The optical disk memory according to claim 6, wherein, when overwriting, data indicating the layer is always recorded after confirmation. 8. The optical disk memory according to claim 1, wherein at least one layer determination area is provided at a radial position on an inner peripheral side or an outer peripheral side in a disk surface.