JP2003303419A - Optical disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk in which a high C/N is secured, the constitution of a demodulation circuit is simplified and two kinds of sub information are superimposed on a data track. <P>SOLUTION: In recording sub information such as an address in a rewritable optical disk such as a phase transition medium and an MO medium or a write- once type optical disk such as a pigment base medium, a track groove for recording the sub information is formed while wobbling it in the radial direction of the optical disk, one of data '0'/'1' constituting first sub information is recorded by the wobble of a first frequency, the other of the data '0'/'1' constituting the first sub information is recorded by the wobble composed of the section of the wobble of the first frequency and the section of the wobble of a second frequency different from the first frequency, and the data '0'/'1' constituting second sub information are recorded by the presence/absence of the phase transition of the wobble. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rewritable optical disc using a phase change medium or a magneto-optical (MO) medium,
Alternatively, the present invention relates to a write-once type (write-once type) optical disc using a dye-based medium or the like, and particularly relates to an optical disc in which addresses and the like are stored by a wobble recording method suitable for handling a large amount of data such as image data and audio data. .

[0002]

2. Description of the Related Art DVDs (digital video disks), MO disks, CDs (compact disks) and the like have been commercialized as large-capacity storage media used in computers and the like. Further, with the spread of computers, users often edit data stored in a storage medium, and there is an increasing need for a storage medium that can change or add data.

As a rewritable storage medium in which a user can change data many times, a DVD-RAM (a memory capable of reading and writing at any time) using a phase change medium, an MO disk using an MO medium, CD-RW (Re
Writable). Further, as a write-once type (write-once type) storage medium in which a user can write data only once, there is a CD-R using a dye-based medium. Sub-information such as an address for recognizing a position where data is written on these storage media is stored in advance in these storage media.

In order to store the sub information such as the address,
On the DVD-RAM or MO disc, an ID section (Identification section) is arranged as a pre-pit for each frame which is the minimum unit for storing user data. However, this pre-pit address method has drawbacks that it is difficult to manufacture a disk and the utilization efficiency of the physical format is poor.

On the other hand, a wobble recording system by FM modulation (frequency modulation) is used for address management in the above-mentioned CD-RW and CD-R. Here, the wobble means meandering, and indicates a structure in which tracks on the disk meander in the radial direction of the disk. Then, in the CD-RW and the CD-R, the address is changed by changing the frequency of the wobble (meander) of the track.
That is, it is stored by FM (frequency) modulation of the wobble. FIG. 5 is a diagram showing a conventional recording method using FM modulation. As shown in FIG. 5, sub information such as an address is recorded by changing the frequency of the wobble between data "0" and data "1". There is.

[0006] In this case, for example, a CD 1x speed (linear speed 1.2 m
/ s), the wobble frequency is 21.05KHz: data “0” and the wobble frequency is 23.05KHz: data “1”. As a result, in the data demodulation circuit, a frequency change of ± 1KHz around 22.05KHZ occurs. It is necessary to detect and determine the data “0” and “1”. Naturally, the frequency spectrum distribution has a characteristic that it is divided into two peaks of 21.05 KHz and 23.05 KHz that are very close to each other, and there is a problem that it is difficult to secure a high C / N ratio. On the other hand, it is necessary to detect a minute difference in frequency. Has a high C / N
Ratio is required. Further, since the physical lengths of the data "0" and "1" are different (due to different frequencies), the demodulation circuit becomes complicated. Further, there is a drawback that only one type of sub information such as an address can be superimposed on the wobble track.

[0007]

The present invention has been made in consideration of such circumstances, and its purpose is to achieve high C /
An object of the present invention is to provide an optical disc that can secure an N ratio, can simplify the configuration of a demodulation circuit, and can superimpose two types of sub information on a data track.

[0008]

The present invention has been made to solve the above-mentioned problems, and the invention described in claim 1 is a rewritable optical disk such as a phase change medium or an MO medium or a dye-based medium. In the write-once type optical disc, the track groove for recording data is formed while wobbled in the radial direction of the disc, and one of binary logical data “0” / “1” forming the first sub information is formed. The other one of the binary logic data “0” / “1” which is recorded by the wobble of the first frequency and constitutes the first sub-information,
Binary logical data "0" / "1" recorded by a wobble composed of a wobble section of the first frequency and a wobble section of a second frequency different from the first frequency and forming second sub information. Is recorded according to the presence or absence of the phase transition of the wobble.

According to a second aspect of the present invention, in the optical disc of the first aspect, the first sub information is constituted by 2
In the wobble in which the other of the value logic data “0” / “1” is recorded, the wobble section of the second frequency is configured to be an integral multiple of the cycle of the wobble of the first frequency. Characterize. According to a third aspect of the present invention, in the optical disc according to the first or second aspect, the second frequency is 2k times (k; a positive integer) or 1 / (2k) times the first frequency. Is characterized in that.

The invention described in claim 4 is the optical disk described in claim 3, wherein the value of the suspension k is 1. According to a fifth aspect of the present invention, in the optical disc according to any one of the first to fourth aspects, the second frequency section is arranged so as to be displaced so that the section of the second frequency does not match the transition point of the phase of the wobble. It is characterized by being. According to a sixth aspect of the present invention, in the optical disc according to any one of the first to fifth aspects, the binary logical data “1” forming the second sub-information has a phase of the wobble. It is characterized in that it is recorded by the transition to the wobble phase of the immediately preceding data.

According to a seventh aspect of the invention, in the optical disc according to any one of the first to sixth aspects, the phase transition is in the vicinity of 180 degrees. The invention described in claim 8 is the optical disc according to any one of claims 1 to 7, wherein the first or second optical disc is used.
One or both of the sub-information of is the address information.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing the structure of the optical disc according to the embodiment. Optical disc DS
A track is provided on the surface of, and first and second types of sub-information are pre-recorded along the track. User data is superposed and recorded on the track on which the sub information is recorded. Here, the sub-information is information other than user data, and a typical example is an address. Further, various parameter information related to the disc is also included in the sub information.

The optical disk DS is, for example, a rewritable optical disk such as a DVD-RAM, a CD-RW using a phase change medium, an MO disk using an MO medium, or a write-once such as a CD-R using a dye-based medium. Type optical disc. As shown in the figure, a wobble track WT1 is provided on the surface of the optical disc DS, and user data is recorded along the wobble track WT1. Here, the wobble means a meander, and indicates a structure in which tracks are meandered in the radial direction of the optical disc DS.

FIG. 3 is an enlarged view showing the detailed structure of the wobble track WT1 on the optical disc DS. A meandering track groove T is provided on the surface of the optical disc DS, the bottom of the track groove T is called a groove G, and a portion sandwiched between adjacent track grooves T is called a land L.
The waviness (meander) of the track groove T is called a wobble. When user data is recorded on the optical disc DS by using the land & groove recording method, recording marks P are formed on both the land L and the groove G. Also,
When the user data is recorded by the groove recording method, the recording mark P is formed only on the groove G. Then, to read the recorded data, the optical disc DS
Light H is incident from the bottom surface of the.

Next, the recording method of the above-mentioned first and second sub information will be described. FIG. 1 is a diagram for explaining a recording method in an optical disc according to the first embodiment of the present invention. In the optical disc according to the first embodiment,
Recording the first side information by frequency modulation of the wobble,
The second side information is recorded by wobble phase modulation.

That is, first, FIGS. 1A and 1B.
As shown in, the data "1" of the first sub information is recorded by the wobble of the frequency Fw and the data "0".
Is the wolve section of the frequency Fw and 1 / of the frequency Fw
It is recorded by a wobble composed of a wobble section of two frequencies Fwb (= Fw / 2). In this case, the data ”
1 "is recorded by 12 cycles (12Tw) of the frequency Fw wobble, and data" 0 "is 5 cycles of the frequency Fw wobble (5Tw) + 1 cycle of the frequency Fwb wobble (2Tw) + 5 cycles of the frequency Fw wobble (5Tw). Recorded by.

As shown in FIGS. 1C and 1D, the second sub information is recorded depending on whether the phase of the wobble waveform of the immediately preceding data is shifted by 180 degrees or not. That is, the data "1" is recorded by the wobble waveform in which the phase of the wobble waveform of the immediately preceding data is shifted by 180 degrees, and the data "0" is recorded by the wobble waveform without phase shift.

In the optical disc according to the first embodiment, as shown in FIGS. 1E to 1G, the first and second sub information are superposed and recorded by the frequency modulation and the phase modulation of the wobble described above. Has been done. In the example of FIG. 1, first, the first sub information “0” is recorded by a wobble having a section of frequency Fw and a section of frequency Fwb, and the second sub information “0” is recorded immediately before. It is recorded by setting no shift from the waveform. Next, the first sub information "1" is recorded by the wobble of the frequency Fw, and the second sub information "1" is recorded by shifting the wobble waveform immediately before by 180 degrees. The same applies to the following first sub-information "0" and second sub-information "1".

Next, a recording method for an optical disc according to the second embodiment of the present invention will be described with reference to FIG. First, in the first sub information, as shown in FIGS. 4A and 4B, data “1” is recorded by the wobble of the frequency Fw, and data “0” is the wobble section of the frequency Fw. And the frequency Fwb (= 2F
It is recorded by a wobble consisting of the wobble section of w). In this case, the data “1” is recorded by 12 cycles (12 Tw) of the frequency Fw wobble, and the data “0” is frequency Fw wobble 5 cycles (5 Tw) + frequency Fwb wobble 4 cycles (2 Tw) + frequency Fw wobble. It is recorded by 5 cycles (5 Tw).

The recording method of the second sub information is the same as that of the first embodiment described above (see FIGS. 4C and 4D). Then, in the optical disc according to the second embodiment,
As shown in FIGS. 4E to 4G, the first and second sub-information are superposed and recorded by the frequency modulation and the phase modulation of the wobble described above.

As described above, according to the first and second embodiments, the sub-information data "0" and "1" can be easily expressed, and the first sub-information data "0". Also, the physical lengths for expressing the data “1” can be made equal (both 12 Tw in the example of FIG. 1). Further, as a characteristic of two wobble frequencies, Fw = 2 × Fwb or F
Since they are set to a harmonic relationship of wb / 2, they are two frequencies but emphasize each other, and as a result,
It is also possible to easily realize a high C / N ratio. Further, in the sub information demodulation circuit, the PL
Even when an L (Phase Locked Loop) signal is generated, it can be realized extremely easily due to the above characteristics.

Further, in the above embodiment, in order to prevent the portion where the frequency is changed by frequency modulation and the portion where the phase is changed by phase modulation from overlapping, the wobble (1 1
It is arranged at the intermediate point of 2Tw section), and the phase transition point by the phase modulation is arranged at the end of the wobble expressing one data. As a result, mutual influences can be prevented and the demodulation circuit can be easily configured.

Further, in the above-mentioned embodiment, by using frequency modulation and phase modulation together, it is possible to form two different types of sub-information in one track groove. It is possible to superimpose a double amount of information as compared with a simple method in which only one sub information is formed in the track groove. As a result, according to the present invention, it is possible to provide a physical format of an optical disc suitable for extremely large capacity.

[0024]

As described above, according to the first aspect of the present invention, by combining frequency modulation and phase modulation, it is possible to superimpose two types of sub-information on one track groove, and a large capacity is achieved. It is possible to provide a disc format suitable for conversion. Further, according to the invention of claim 2, the physical length required for expressing "0" and "1" forming the first sub-information can be made constant, which simplifies the demodulation circuit. Can be configured to. Further, according to the third aspect of the invention, the first and second frequencies have a harmonic relationship with each other, so that there is an advantage that the C / N ratio is easily secured. Also, the PLL operation can be realized very easily, and the demodulation circuit can be easily configured.

Further, according to the invention of claim 4, the variation width of the frequency of the wobble can be set to a necessary minimum. According to the invention of claim 5, frequency modulation and phase modulation do not adversely affect each other during demodulation,
As a result, it is possible to reliably separate and demodulate the first and second sub information with a simple configuration. Further, according to the invention of claim 6, only the phase transition need be performed, not the absolute phase information of the wobble, so that the phase modulation can be realized with an extremely simple configuration.

Further, according to the invention of claim 7, the amplitude information can be superposed on the track groove with a very simple structure, and the disc manufacturing becomes very easy. Further, claim 8
According to the invention, since the address information is recorded as the sub information, it is not necessary to specially provide an area for indicating the address information in the disc format, and an extremely highly efficient format can be provided.

[Brief description of drawings]

FIG. 1 is a waveform diagram for explaining a sub information recording system for an optical disc according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an optical disc and its track structure according to the same embodiment.

FIG. 3 is an enlarged perspective view showing a configuration of tracks of the optical disc shown in FIG.

FIG. 4 is a waveform diagram for explaining a sub information recording system for an optical disc according to a second embodiment of the present invention.

FIG. 5 is a waveform diagram for explaining a sub information recording method in a conventional optical disc.

[Explanation of symbols]

DS ... Optical disc WT1 ... wobble truck

Claims (8)

[Claims] 1. A rewritable optical disc such as a phase change medium or an MO medium or a write-once optical disc such as a dye-based medium, in which track grooves for recording data are formed while wobbled in the radial direction of the disc. Binary logical data “0” / “1” that compose the sub information of 1
One of them is recorded by a wobble of a first frequency, and binary logic data “0” / which constitutes the first sub information is recorded.
The other one of "1" is recorded by a wobble including a wobble section of the first frequency and a wobble section of a second frequency different from the first frequency, and binary logic which constitutes second sub information. Data “0” / “1”
Is recorded depending on the presence or absence of the phase transition of the wobble. 2. In the wobble for recording the other of the binary logic data “0” / “1” forming the first sub-information, the wobble section of the second frequency corresponds to the first frequency. The optical disc according to claim 1, wherein the optical disc is configured to be an integral multiple of the period of the wobble. 3. The method according to claim 1, wherein the second frequency is 2k times (k; a positive integer) or 1 / (2k) times the first frequency. optical disk. 4. The optical disk according to claim 3, wherein the value of the suspension k is 1. 5. The section according to any one of claims 1 to 4, wherein the sections of the second frequency are arranged so as not to coincide with a transition point of the phase of the wobble. Optical disc. 6. The binary logical data “1” that constitutes the second sub-information is recorded when the phase of the wobble is changed from the phase of the wobble of the immediately preceding data. The optical disc according to any one of claims 1 to 5. 7. The optical disc according to claim 1, wherein the phase transition is in the vicinity of 180 degrees. 8. The optical disc according to claim 1, wherein one or both of the first and second sub-information is address information.