JPH09259438A - Multilayered disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the access time at the time of continuous access of a head to data tracks of recording layers vertically adjacent to each other in the multilayered disk. SOLUTION: In the multilayered disk 10 constituted by arranging plural discoid recording layers having helical data tracks formed, helical patterns of the data tracks on the individual recording layers 1, 2 and 3 are arranged alternately clockwise and counter clockwise as seen from the side of a head 5 to access the tracks, and the direction of recording data to such a circular- formed data track is specified alternately to be the direction from an inner circumferential part of the disk to an outer circumferential part and the direction from the outer circumferential part to the inner circumferential part in the individual recording layers 1, 2 and 3 adjacent to each other up and down. When the multilayered disk 10 is exclusively used for read-out only, recording lengths of data recorded in the data tracks on the individual recording layers 1, 2 and 3 are approximately equalized, and are recorded in positions overlapped with each in the vertical direction on the individual recording layers 1, 2 and 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer disc, and more particularly to a multi-layer disc made by arranging a plurality of disc-shaped recording layers in which data tracks for recording data are spirally formed.

[0002]

2. Description of the Related Art Speaking of conventional recording media, there are known audio compact compact cassettes using a magnetic tape and video recording video cassettes. However,
Since the data recorded on these recording media cannot be randomly accessed and the recorded data is analog information, the reproduced data may include noise, or the data may deteriorate when copied, or the data may be recorded for a long time. There was a problem such as deterioration of data when saved.

Therefore, as a recording medium, data is converted into a digital signal and recorded on a data track on a disk, the data track is irradiated with a laser beam, and the return light is used for reading. Optical discs capable of achieving this have been put into practical use. In this optical disc,
Recesses or protrusions called pits are formed in rows on a data track of an optical disc to record data, the presence or absence of pits is made to correspond to “1” or “0” of data, and a laser beam is applied to these pits. It is read only by irradiating and using the reflected light to read out. Typical examples of such an optical disc include a CD (compact disc) for music, an LD (laser disc) for video, and a compact DV for video.
Development of D (digital video disc) is also in progress. Such CDs, LDs for long-term recording, and DVDs
In, the data is continuously recorded in a spiral form from the inner peripheral portion to the outer peripheral portion of the disc, and the linear velocity at the time of data reading is constant (CLV).

Further, in recent years, a magneto-optical disk capable of recording data on a recording medium with a laser beam and magnetism and reading the data using the laser beam has also been put into practical use. As a typical example of such a magneto-optical disk, an MD (mini disk) and a magneto-optical disk used as an external memory of a computer are known. MD is also CLV, and data is continuously recorded in a spiral form from the inner peripheral portion to the outer peripheral portion.

On the other hand, an optical disc such as a CD has a specification that data is recorded on only one side. Therefore, in order to increase the recording capacity, in addition to increasing the recording density of the recording medium on the disc, a recording layer on the disc is used. There is a method of making multiple layers. As the multi-layer disc, a two-layer type such as a DVD can be considered, but in the future, a multi-layer disc having three or more layers is also possible.

[0006]

However, if data tracks are recorded in each recording layer of a multi-layer disc in a spiral shape from the inner peripheral portion toward the outer peripheral portion in the same manner as in the conventional optical discs, data is recorded. There is a problem that the access time when the head moves between layers becomes long.
That is, when writing data to the first recording layer as much as possible and then writing data to the second recording layer, or after reading data from the first recording layer, When reading the subsequent data from the data in the second recording layer, the head has to move from the outermost peripheral portion to the innermost peripheral portion of the disk, and there is a problem that access takes time.

Therefore, according to the present invention, in a multi-layer disc, the access time can be shortened when the head continuously accesses the data tracks of the recording layers vertically adjacent to each other. The purpose is to provide.

[0008]

FIG. 1 shows the principle configuration of the present invention for achieving the above object. According to the present invention, as shown in FIG. 1, in a multi-layer disc constituted by arranging a plurality of disc-shaped recording layers in which data tracks for recording data are spirally formed, for example, a disc having three layers. In a multi-layer disc 10 formed by stacking recording layers 1, 2, and 3 in layers,
The spiral shapes of the data tracks 2 and 3 are arranged such that the right-handed spiral shape and the left-handed spiral shape are alternately arranged when viewed from the side where the head 5 for accessing the data track is located. I am trying.

In this case, there are two kinds of data recording directions on the spiral data track, that is, the direction from the inner peripheral portion of the disc toward the outer peripheral portion and the direction from the outer peripheral portion of the disc toward the inner peripheral portion. The adjacent recording layers are configured so that the data recording directions on the data tracks are different from each other. When the multi-layer disc is a read-only disc, the recording lengths of the data recorded on the data tracks on each recording layer are made substantially equal, and the data are overlapped in the vertical direction on each recording layer. It should be recorded in.

According to the multi-layer disc of the present invention, the data tracks formed on each recording layer of the multi-layer disc are alternately spiraled from the inner circumference side to the outer circumference side of the disk and in the opposite direction. Therefore, the data recorded on each recording layer is continuous at the outermost or innermost portion of the disc, and the head is used when the head continuously accesses the data on the recording layers that are vertically adjacent to each other. The movement amount of the head is minimized and the head access time is shortened.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to specific examples with reference to the accompanying drawings. In addition,
The multi-layer disc targeted by the present invention is a multi-layer disc in which data tracks for recording data are spirally formed. FIG. 2 is an assembly perspective view showing the structure of the multilayer disc 30 according to the first embodiment of the present invention.
In this embodiment, a multi-layer disc 30 will be described in which three disc-shaped recording layers 1, 2, and 3 are stacked. When the head 5 is located outside the first recording layer 1, a disk-shaped substrate layer made of a member such as polycarbonate is arranged outside the first recording layer 1, between the recording layers, or between the recording layers. A protective layer or the like may be arranged outside the third recording layer 3, but the existence of these layers is not directly related to the present invention. Therefore, in the following embodiments, description and illustration of these substrate layers and protective layers will be given. Is omitted.

In the multi-layer disc 30 having the three-layer structure of the first embodiment, the recording layers 1, 2, and 3 to be overlapped with each other.
The spiral shape of the data track formed above is seen from the side where the head 5 for accessing the data track is located, the first recording layer 1 has a right-handed swirl shape, and the second recording layer 2 has a left-handed swirl shape. In the recording layer 3 of No. 3, as the right-handed spiral shape again, the right-handed spiral shape and the left-handed spiral shape are alternately arranged.

Further, in this embodiment, there are two types of data recording directions on the spiral data track: a direction from the inner peripheral portion of the disc to the outer peripheral portion and a direction from the outer peripheral portion of the disc to the inner peripheral portion. The recording layers 1, 2 and 3 which are vertically adjacent to each other are configured so that the recording directions of data on the data tracks are different from each other. That is, as shown in FIG. 2, when the rotation direction of the multilayer disc 30 is counterclockwise when viewed from the side where the head 5 is located, the data recording direction in the first recording layer 1 is the inner circumference of the disc. From the outer edge to the outer edge, and in the second recording layer 2, the data recording direction is from the outer edge to the inner edge of the disc.
In the third recording layer 3, the data recording direction is the direction from the inner peripheral portion to the outer peripheral portion of the disc.

Here, when the writing or reading of data by the head 5 is performed in order from the first recording layer 1 to the second recording layer 2 and the third recording layer 3, the data is read on the first recording layer 1. Data is recorded on the data track T1 from the spiral start point A on the inner peripheral portion toward the end point B of the spiral on the outer peripheral portion, and the data is recorded on the data track T2 on the second recording layer 2 in the spiral portion on the outer peripheral portion. The data is recorded from the end point C of the spiral to the spiral start point D of the outer peripheral part, and in the data track T3 on the third recording layer 3, the data is recorded from the spiral start point E of the inner peripheral part to the end point F of the spiral of the outer peripheral part. Recorded towards. The recording direction of this data is shown in the vertical cross section of the multilayer disc 30 in FIG. 3 (a). In this case, the data address is
As shown in FIG. 3B, the spiral starting point A of the first recording layer 1
From the point toward the end point B of the spiral. In addition, the address of the end point B (outer peripheral portion) of the spiral of the first recording layer 1 and the second
The address of the data in the second recording layer 2 increases from the end point C of the spiral toward the spiral start point D. Similarly, the spiral starting point D (inner peripheral portion) of the second recording layer 1
And the address of the spiral start point E (inner peripheral portion) of the third recording layer 3 are continuous, and the address of the data in the third recording layer 3 is from the spiral start point E to the end point D of the spiral. Grows toward. In the embodiment configured as described above, when the head 5 continuously reproduces all the data on the multilayer disc 30, the head 5 is the first disc of the multilayer disc 30 as shown in FIG. 2 (a). The reproduction of data is started from the point A on the inner peripheral portion of the recording layer 1 and is moved in the outer peripheral direction of the multilayer disc 30. When the head 5 reaches the point B on the outer peripheral portion of the first recording layer 1, the head 5 changes the data reading layer from the first recording layer 1 to the second recording layer 2. The read layer of the head 5 can be changed by changing the focal length of the laser beam. Then, the head 5 continuously reproduces data from the point C on the outer peripheral portion of the second recording layer 2 and moves in the inner peripheral direction of the multilayer disc 30. After that, when the head 5 reaches the point D on the inner peripheral portion of the second recording layer 2, the head 5 changes the data reading layer from the second recording layer 2 to the third recording layer 3. Further, the head 5 continuously reproduces data from the point E on the inner peripheral portion of the third recording layer 3, and the multilayer disc 30
And the reproduction is ended at the point F on the outer peripheral portion.

As a result, the reproduction of data from the multi-layer disc 30 is in the order of A → B → C → D → E → F, and B → C and D → E only change the read layer. The head 5 can read continuous data without moving. Rotation control is constant linear velocity (CLV)
In the case of the multi-layered disc as described above, in CLV, it takes time for the head 5 to access (move) the disc. For example, if data is recorded in a spiral shape in the same turning direction from the inner peripheral portion to the outer peripheral portion on each of the recording layers 1 to 3 of the multi-layered disc 30, the head 5 is a disc having a diameter of 12 cm. When reading is started from the innermost peripheral portion of the first recording layer 1 and reaches the outermost peripheral portion, the head 5 has to access the innermost peripheral portion in order to read the next data, and this access requires 120 ms. ~ 250
It takes ms.

On the other hand, in the multilayer disc 30 of the present invention,
Even when the head 5 starts reading from the innermost peripheral portion of the first recording layer 1 and reaches the outermost peripheral portion, the head 5 hardly moves and the focal length of the laser beam emitted from the head is changed. All you have to do is change the readout layer. Since the change of this layer is only a few ms, in the multi-layer disc 30 of the present invention, the read time of the data when the read data is spread over a plurality of layers is set based on the above-mentioned conventional technique. It can be significantly shortened compared to a disc.

Further, the change of the read layer depends on the head, and the same effect can be obtained even with an inexpensive drive device which does not use a high torque motor. by the way,
If the multi-layer disc is a read-only disc and the data is written so that the data can be written in order from the first recording layer, when the data written to the last recording layer is less than the storage capacity of the recording layer, The access time becomes long when the head reads to the end of the data and then returns to the beginning of the data. A multilayer disc according to a second embodiment of the present invention, which solves this problem, will be described below with reference to FIGS.

First, the multi-layer disc is a two-layer disc 2.
A case in which the storage capacity is 0 and the storage capacity of one layer is 5 gigabytes will be described with reference to FIGS. 4 (a) to 4 (c). It is assumed that the write data is 8-gigabyte data as shown in FIG. Here, as shown in FIG. 4 (b), 5 gigabytes of data are written to the first recording layer 1 to fill its storage capacity, and then the remaining 3 gigabytes of data are written to the second recording layer 2. Think about the case. When reproducing such a two-layer type disc 20, first, 5 GB data recorded on the first recording layer 1 is moved from the inner peripheral portion to the outer peripheral portion of the first recording layer 1 by a head (not shown). Then, the data of the second recording layer 2 is read from the outer peripheral portion toward the inner peripheral portion. Then, when the data of the first portion of the first recording layer 1 is read again after the reading of the data of the second recording layer 2 is completed,
The head moves from the end portion of the data recorded on the inner peripheral side of the second recording layer 2 to the data recording area of 2 gigabytes without data and moves to the innermost peripheral portion of the first recording layer 1. There must be. Therefore, when the data recorded on the dual-layer disc 20 is repeatedly reproduced many times, 2
After reading all the data recorded on the layered disc 20, as shown by the dotted line in FIG. 4 (b), the head needs an access time to move the data recording area of 2 gigabytes. .

In view of such a problem, in the present invention, when writing data on a read-only multi-layer disc, the recording length of the data recorded on the data track on each recording layer is made substantially equal, and The recording is performed at positions vertically overlapping on each recording layer. For example, when writing data of 8 gigabytes as shown in FIG. 4 (a) to the dual-layer disc 20, the data of 4 gigabytes obtained by dividing this data into two equal parts is shown in FIG. 4 (c). Then, the data is distributed and written to the first recording layer 1 and the second recording layer 2. The data to be distributed and written in the first recording layer 1 and the second recording layer 2 is the two-layer disc 20.
Write so that they overlap in the axial direction of.

When reproducing a two-layer disc 20 on which data is recorded as shown in FIG. 4 (c), the leading end of the data on the first recording layer 1 and the end of the data on the second recording layer are substantially the same. Since the end of the data on the first recording layer 1 and the end of the data on the second recording layer 2 coincide, the two-layer disc 20
Even in the case where the data recorded in (1) is repeatedly reproduced many times, the access distance of the head is shortened and the access performance is improved even in the random access.

Next, the multilayer disc is a three-layer disc 3
The case where the storage capacity is 0 and the storage capacity of one layer is 5 gigabytes will be described with reference to FIGS. 5 (a) to 5 (c). It is assumed that the write data is 12 gigabyte data as shown in FIG. Here, as shown in FIG. 5 (b), 5 gigabytes of data are written in the first recording layer 1 and the second recording layer 2 to fill the storage capacity, and then the data is left in the third recording layer 3. Consider the case where 2 gigabytes of data are written.

When reproducing such a three-layer disc 30, first of all, the first recording layer 1 is read by a head (not shown).
The data of 5 gigabytes recorded on the first recording layer 1 is read from the inner peripheral portion toward the outer peripheral portion, and then the second recording layer 2 is recorded.
The data of the recording layer 2 is read from the outer peripheral portion toward the inner peripheral portion, and the remaining 2 gigabytes of data is further read from the inner peripheral portion of the third recording layer 3 toward the outer peripheral portion. Then, when the data of the first portion of the first recording layer 1 is read again after the reading of the data of the third recording layer 3 is completed, the head is recorded on the outer peripheral side of the third recording layer 3. It is necessary to move the data recording area of 2 gigabytes from the end portion of the data to the innermost peripheral portion of the first recording layer 1. Therefore, in the case where the data recorded on the three-layer disc 30 is repeatedly reproduced, after reading all the data recorded on the three-layer disc 30, the dotted line in FIG. As shown by,
Access time is required to move the gigabyte data recording area.

Therefore, when writing 12 gigabytes of data to the three-layer disc 30 as shown in FIG.
The data of 4 gigabytes obtained by dividing this data into three equal parts is shown in FIG.
As shown in (c), the data is distributed and written to the first recording layer 1, the second recording layer 2, and the third recording layer 3. Then, the data to be distributed and written to the first recording layer 1 to the third recording layer 3 are written so as to overlap in the axial direction of the three-layer disc 30.

When reproducing the three-layer type disc 30 on which data is recorded as shown in FIG. 5C, the front end of the data of each recording layer 1 to 3 and the end of the data are substantially the same. Even when the data recorded on the three-layer disc 30 is repeatedly reproduced many times, the access distance of the head is shortened and the access performance is improved even for random access.

[0025]

As described above, according to the present invention, in the multi-layer disc, the data tracks formed on the respective recording layers are alternately directed from the inner side to the outer side of the disc and the opposite direction. Since it has a spiral shape, the data recorded in each recording layer is continuous at the outermost or innermost portion of the disc, and the head continuously accesses the data of the discs vertically adjacent to each other. In this case, the amount of movement of the head is minimized and the head access time can be shortened.

[Brief description of drawings]

FIG. 1 is a principle configurational diagram showing a configuration of a multilayer disc of the present invention.

FIG. 2 is an assembled perspective view showing a configuration of an embodiment of a multi-layer disc of the present invention.

3A is an explanatory diagram showing an example of a recording direction of data on each recording layer of the multilayer disc of FIG. 2, and FIG. 3B is an explanatory diagram showing addresses of the data of FIG.

FIG. 4A is an explanatory diagram showing an example of the amount of data to be recorded on a dual-layer disc, and FIG. 4B is a diagram showing the amount of data of FIG. FIG. 3C is an explanatory view for explaining the problems in the case, and FIG. 3C is an explanatory view for explaining the embodiment of the present invention in the case where the data amount in FIG. .

5A is an explanatory diagram showing an example of the amount of data to be recorded on a three-layer type disc, and FIG. 5B is a diagram showing the amount of data of FIG. FIG. 3C is an explanatory view for explaining the problems in the case, and FIG. 3C is an explanatory view for explaining the embodiment of the present invention in the case where the data amount in FIG. .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st recording layer 2 ... 2nd recording layer 3 ... 3rd recording layer 5 ... Head 10 ... Multilayer type disc 20 ... Two-layer type disc 30 ... Three-layer type disc

Claims (3)

[Claims] 1. A multi-layered disc comprising a plurality of disc-shaped recording layers in which data tracks for recording data are spirally formed, wherein the data tracks on each of the recording layers have a spiral shape. When viewed from the side where the head for accessing the data track is located, a right-handed spiral shape and a left-handed spiral shape are alternately arranged. 2. The multilayer disc according to claim 1, wherein data is recorded on the spiral-shaped data track from an inner peripheral portion to an outer peripheral portion of the disc and from an outer peripheral portion of the disc. There are two kinds of directions toward the inner peripheral portion, and the recording directions of the data on the data tracks are different in each of the vertically adjacent recording layers. 3. The multi-layer disc according to claim 1, wherein the multi-layer disc is a read-only disc, and a recording length of data recorded in a data track on each of the recording layers is substantially the same. A multi-layer disc, which is even and in which data is recorded at positions vertically overlapping on each recording layer.