JP2007164983A - Information recording carrier and method of reproducing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information recording carrier using address recording without recording capacity reduction nor mutual interference with a signal track. <P>SOLUTION: A groove constituting the information recording carrier meanders, and data is subjected to frequency shift keying. This meandering groove and a straight groove are alternately arranged, and especially a single or a plurality of waves are digitally recorded as 1 channel bit. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an information record carrier used in a system for recording and / or reproducing information, in particular by optical means, and a method for reproducing the information record carrier.

  Conventionally, there is a system for reading information by relatively moving an information record carrier, and optical means, magnetic means, electrostatic capacity means, and the like are used for reproduction. Among these, a system that performs recording and / or reproduction by optical means has deeply penetrated daily life (here, “recording and / or reproduction” means three modes of recording only, reproduction only, and recording and reproduction). . For example, there are DVD-RAM and DVD-RW as a recording / reproducing information recording carrier using light of wavelength λ = 650 nm (“DVD” means a digital versatile disk). As described above, although the record / reproduction type information record carrier has been put into practical use and has appeared on the market, the development of a technique for efficiently embedding address information in the record / reproduction type information record carrier is still in the process of development. Record carriers require improved conventional address recording techniques or new address recording techniques.

  The purpose of efficiently embedding address information is to first embed address information at a low error rate without effectively reducing the area used for recording and reproduction, and secondly, the embedded address information is mainly used. This is to embed the recording mark with a low error rate without interfering with the recording / reproducing area.

  Regarding the first target, for example, in an information record carrier employing a header type address represented by DVD-RAM, the address information is recorded by a pit string (referred to as a header) by cutting the main recording / reproducing area. . Since the header has the same format as the read-only information record carrier, the error rate of the address information can be kept very low. However, since recording cannot be performed in this header area, the total capacity of an information record carrier with a limited area is reduced. Therefore, an address recording method that does not use a header is necessary.

  Regarding the second target, for example, in an information record carrier employing a land pre-pit type address typified by DVD-RW, the recording / reproducing area is continuous and there is no cut area. The address information is prepared as pits, but the pits (land pre-pits) are distributed over a wide area and recorded between the recording tracks. Accordingly, although the recording capacity does not decrease, the land prepit and the recording signal (recording mark) are arranged in parallel, so that both signals interfere with each other. As a result, the error rate of the address increases and the error rate of the recording mark also increases. Therefore, an address recording method that does not use land prepits is required.

  As a solution to such a requirement, there is a method in which address information is recorded by continuously forming grooves substantially parallel to the information record carrier and wobbling the grooves. For example, for a rewritable DVD disc (so-called DVD + RW) described in ECMA / TC31 / 99/43, an address recording method is defined in which a groove is meandered by phase shift modulation. According to this recording method, since the address is recorded in the groove by phase shift keying, a header is unnecessary and there is no loss of capacity.

  FIG. 16 illustrates the concept of phase shift modulation in this rewritable DVD disc. On the information record carrier (not shown), a plurality of substantially parallel groove continuous bodies 150 are formed as a fine pattern. The continuous body 150 includes a groove 151 and an inter-groove portion 152, and is substantially parallel to each other. The groove 151 and the groove portion 152 have different heights (the difference in height is, for example, λ / 8n where λ is the recording wavelength and n is the refractive index of the recording light transmitting member). The grooves 151 meander in a sinusoidal shape.

As shown in FIG. 17, the address is recorded in such a manner that phase information is given to the groove 151. That is, sin0 and sinπ are treated as 0 and 1, respectively, and address information is recorded. In the reproduction, since the phase switching point 153 carries address information, the push-pull signal can be reproduced by, for example, envelope detection.
When address information is recorded by phase shift modulation in this way, a header is not necessary and there is no loss of capacity. Reproduction is also possible by known envelope detection.

  However, the present inventor examined the address recording method under various adverse conditions. Specifically, the present inventor attempted to reproduce the address by recording user data in the groove 151 of the phase change disk created by this method. However, it has been found that the recorded user data leaks into the address signal, causing a failure in address detection.

  There is no frequency overlap between the recorded data and the address information because the information density is extremely different. However, from the viewpoint of address reproduction, it has been found that recorded user data behaves like noise, and that the detection of the address, specifically the detection of the phase switching point 153, is often erroneous. As a countermeasure, when the envelope detection playback was changed to synchronous detection playback, the error rate dropped by almost an order of magnitude, but the effect was still small. In addition, we tried to increase the meandering of the sine wave so that the error rate would be small, but although it was effective to some extent, it also increased interference, and the error rate of user recording deteriorated or was severe Sometimes tracking became unstable.

Such a problem is caused by the fact that this address recording method depends on a minute shape change of the phase switching point 153.
In addition, in this address recording method, the address of the adjacent track leaks, and the phenomenon of interference with the main address at a frequency of once every several tracks is also observed, coupled with the difficulty in detecting the phase switching point 153, and the reliability of the information record carrier Was significantly reduced. Accordingly, there has been a demand for a recording method based on modulation other than phase shift modulation and a novel groove continuum configuration while taking advantage of data recording by groove meandering.

  Therefore, the present invention proposes a groove modulation method instead of phase shift modulation, and the main object is to embed address information efficiently. Specifically, first, the address is embedded at a low error rate without effectively reducing the area used for recording / reproduction, and the second embedded address does not interfere with the main recording / reproduction area, It is to embed the recording mark with a low error rate, and thirdly, it is configured to prevent the embedded address from interfering with an adjacent address.

  In the present invention, a gallium nitride-based compound semiconductor light-emitting device (for example, described in Japanese Patent No. 2778405) developed in recent years to increase the recording density of an information record carrier, that is, a short wavelength laser emitting near λ = 350 to 450 nm, Consider that the noise is higher than conventional lasers.

In addition, there is known a technique for multilayering information record carriers in order to increase the recording capacity, but it is also considered that the noise in the reproduction system increases due to this multilayering.
In addition, the present invention also takes into consideration that it corresponds to a light transmission layer incident type information recording carrier developed in recent years in a physical structure.

  An object of the present invention is to provide an information record carrier, an information record carrier reproduction method, and an information record carrier reproduction device in which addresses are efficiently embedded, taking into consideration the latest technical background.

In order to solve the above-described problems, the present invention provides an information record carrier having the following configuration and a method for reproducing the information record carrier.
(1) a support having a fine pattern composed of concentric or spiral tracks;
A recording layer formed on the fine pattern;
And at least a light-transmitting layer formed on the recording layer,
An information recording carrier for reproducing by irradiating the recording layer with a light beam obtained by condensing a laser beam by an objective lens through the translucent layer,
The track is a continuous track of 360 degrees and has at least a meandering groove region,
The meandering groove region is composed of meandering grooves having a frequency shift modulated wave as a groove waveform shape,
The frequency shift modulated wave is composed of a high-frequency wave and a low-frequency wave, and the frequency of the high-frequency wave and the low-frequency wave so that a value obtained by dividing the frequency of the high-frequency wave by the frequency of the low-frequency wave is 1.5. And the phase of the high frequency wave and the phase of the low frequency wave so that the phase of the high frequency wave and the phase of the low frequency wave are continuous at the switching point between the high frequency wave and the low frequency wave. An information record carrier comprising: selecting a wave phase; and both the amplitude direction of the high frequency wave and the amplitude direction of the low frequency wave are radial directions of the information record carrier.
(2) When the wavelength of the laser beam is λ and the numerical aperture of the objective lens is NA,
The pitch P between the tracks has a relationship of P <λ / NA,
When the λ is 405 nm and the NA is 0.85, the thickness of the light transmitting layer is 0.02 to 0.12 mm, and the thickness variation of the light transmitting layer over one surface of the information record carrier is ± 0. 2. The information recording carrier according to claim 1, wherein the information recording carrier has a shape of 002 mm or less.
(3) a support having a fine pattern comprising concentric circular or spiral tracks;
A recording layer formed on the fine pattern;
And at least a light-transmitting layer formed on the recording layer,
An information recording carrier for reproducing by irradiating the recording layer through the light transmitting layer using a light beam obtained by condensing laser light with an objective lens,
The track is formed by arranging a meandering groove region and a straight groove region in which a straight groove is formed adjacent to each other in the radial direction,
The meandering groove region is composed of a meandering groove having a frequency shift modulated wave based on a rectangular wave as a groove waveform shape,
The frequency shift modulated wave is composed of a high frequency wave and a low frequency wave, and the frequency of the high frequency wave is such that a value obtained by dividing the frequency of the high frequency wave by the frequency of the low frequency wave is 1.05 to 5.0. The phase of the high-frequency wave is selected such that the phase of the high-frequency wave and the phase of the low-frequency wave are continuous at a switching point between the high-frequency wave and the low-frequency wave. And the phase of the low frequency wave, and the amplitude direction of the high frequency wave and the amplitude direction of the low frequency wave are both radial directions of the information record carrier.
(4) A method for reproducing an information record carrier for reproducing the information record carrier according to any one of claims 1 to 3,
Irradiating the recording layer with the light beam through the translucent layer;
Generating a push-pull signal based on reflected light from the recording layer of the light beam applied to the recording layer;
And a step of demodulating the frequency shift modulated wave from the push-pull signal.

  As is clear from the above detailed description, according to the information record carrier of the present invention, the track having the meandering groove region and the track having the straight groove region are alternately arranged, so that each has a low error rate and no crosstalk. In addition, it is possible to provide an information record carrier capable of reproducing digital data satisfactorily. In addition, even when a mark is recorded in an inter-groove portion between a track having a meandering groove region and a track having a linear groove region, there is almost no mutual interference with an adjacent track. It is possible to maintain and ensure a high density recording capacity without reducing the capacity.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 21 using preferred examples.
First, an embodiment of the present invention will be described with reference to FIGS. An information record carrier 1 according to an embodiment of the present invention is an information record carrier in which at least one of recording and reproduction is performed mainly by optical means. For example, a phase change recording type information record carrier, a dye type information record carrier, a magneto-optical type information record carrier, a photo-assisted magnetic type information record carrier, and the like.
As shown in FIG. 1, a concave / convex fine pattern is formed as a recording / reproducing area on the surface (laser light irradiation surface) or inside of the information record carrier 1, and the planar structure has a plurality of substantially parallel grooves. The parallel groove | channel continuous body 100 formed adjacently is comprised. In the example of FIG. 1, the parallel groove continuum 100 is drawn in an arc shape for a very small part thereof, but the arc may be continuously connected 360 degrees concentrically or spirally.

  In FIG. 1, the information record carrier 1 is depicted as a circle, but the present invention is not limited to that shape. The card-shaped information record carrier 1 described in FIG. 2 may be used, and in particular, the parallel groove continuous body 100 may be formed in parallel to one side of the card. Moreover, the card-shaped information recording carrier 1 described in FIG. 3 may be used, and the parallel groove continuous body 100 may be formed in a circular shape as in FIG. Although not shown in the drawings, the information record carrier 1 may be tape-shaped or may be perforated.

  The data to be recorded in the present invention is digital data, and is recorded as a groove shape on at least a part of the parallel groove continuous body 100. Therefore, it is permanent data that cannot be rewritten. The type of data is not particularly limited, but it can handle address information, anti-duplication information, encrypted information, an encryption key, and the like. Here, the address information is an absolute address assigned to the entire surface of the information record carrier 1, a relative address assigned to a partial area, a track number, a sector number, a frame number, a field number, time information, an error correction code, etc. For example, the data described in decimal or hexadecimal format is converted into binary format (including examples of BCD code and Gray code). In the following description, for easy understanding, digital data to be recorded is described as address data.

FIG. 4 is an enlarged view of the parallel groove continuum 100 described in FIGS. 1 to 3 and shows its planar fine structure. The parallel groove continuum 100 includes a track 201 having at least a meandering groove region and a track 203 having at least a linear groove region, which are substantially parallel to each other in a macro manner and are alternately arranged. For the sake of explanation, the space between the track 201 having the meandering groove region and the track 203 having the linear groove region is referred to as an inter-groove portion 202. The track 201 having the meandering groove region and the track 203 having the straight groove region have the same height and are different from the height of the inter-groove portion 202.

  Here, the pitch between the track 201 having the meandering groove region and the track 203 having the straight groove region is P, the wavelength of the reproduction light for reproducing the information recording carrier 1 according to the present invention is λ, and the numerical aperture of the objective lens When NA is NA, P <λ / NA is established. For example, as with DVD, when λ = 650 nm and NA = 0.6, P <1083 nm. For example, when a gallium nitride-based compound semiconductor light-emitting element and a high NA pickup are used, P <476 nm when λ = 405 nm and NA = 0.85.

  In the drawing, the track 201 having the meandering groove region and the track 203 having the straight groove region are depicted narrower than the inter-groove portion 202, but each groove width is not limited. Further, the width of the track 201 having the meandering groove region and the width of the track 203 having the straight groove region may be the same or different.

  Further, the meandering fundamental wave is not limited to a sine wave, but can be selected from a triangular wave, a rectangular wave, etc. In particular, when a sine wave is selected, high-frequency components are not included, and high-quality recording with a limited band can be performed. Further, the track 201 having the meandering groove region and the track 203 having the straight groove region may be any of a line shape, a concentric circle shape, and a spiral shape. In particular, in the case of the circular or arc parallel groove continuum 100 as shown in FIGS. 1 and 3, the track 201 having the meandering groove region has a constant angular velocity (CAV) or a constant linear velocity (CLV). ), Or different zones are formed for each radius, and the recording is recorded in a ZCAV (zone constant angular velocity) or ZCLV (zone constant linear velocity) format in which the control is different for each zone. The track 203 having the linear groove region may be a continuous line extending 360 degrees. In any case, what is important is that the meandering groove areas and the linear groove areas are alternately arranged adjacent to each other, and in the case of a disc-shaped information record carrier, these are successively adjacent in the radial direction. Is.

  A track 201 having a meandering groove region records data by frequency shift modulation, and specifically comprises a plurality of portions in which a groove meanders at a constant frequency. Specifically, in the case of binary (binary) data, shape recording is performed by frequency shift modulation using a high frequency portion and a low frequency portion. Further, when the n-value data is multi-valued, the shape is recorded by frequency shift modulation using n types of frequency portions. Hereinafter, an example in which the data is binary will be described with reference to FIG.

  FIG. 5 shows an example in which the data 1, 0, 1, 1, 0 are recorded in shape, and includes a high frequency portion 301 and a low frequency portion 300. The high frequency portion 301 and the low frequency portion 300 correspond to data bits 1 and 0, respectively, and are digitally recorded with the frequency switched for each channel bit. Here, the number of waves constituting each frequency portion is not limited, and the number of waves is composed of one or more waves. However, in order to correctly detect the frequency in the reproducing apparatus and to obtain a certain data transfer rate, considering that it is not redundant, each data bit described above is in the range of 1 to 100 waves, preferably 1 to 30 waves. It is desirable to configure each of the frequency portions corresponding to. The amplitudes of the high frequency portion 301 and the low frequency portion 300 may be the same. However, the amplitude ratio is not limited, and the amplitude of the high frequency portion 301 may be formed larger than that of the low frequency portion 300 in consideration of the frequency characteristics of the playback device. However, in any case, it is necessary to form the amplitude Δ with a relationship of Δ <P with the pitch P. In this way, since the track 201 having the meandering groove region and the track 203 having the straight groove region are not in contact with each other, the address shift-modulated to the different track 201 is reproduced. Sometimes avoids crosstalk. Here, the amplitude Δ refers to the amount of deviation from the center line of the frequency shift modulation to the maximum point or minimum point of the wave. Note that the recorded data can be read by using the push-pull method as in the case of phase shift keying.

  Further, the information record carrier 1 according to the present invention does not limit the physical length of the channel bits constituted by the high frequency portion 301 and the low frequency portion 300 and the magnitude of the amplitude thereof. For example, in FIG. 5, the physical length of the low frequency portion 300 is set longer than that of the high frequency portion 301.

  Further, like the track 211 having the meandering groove region shown in FIG. 6, the amplitudes of the high frequency portion 303 and the low frequency portion 302 are equal to each other, and the length of the high frequency portion 301 is equal to the low frequency portion. The length of 302 may be the same. In this way, 0 and 1 determinations can be made with a sufficient amplitude threshold during reproduction, and series data can be read with one time threshold, thereby simplifying the reproduction circuit. In addition, there is an advantage that the influence can be minimized when there is jitter (fluctuation in the time axis direction) in the reproduction data. If the codes to be recorded are ideally symmetric, the total length of the high frequency portion 301 and the total length of the low frequency portion 302 are equal, and the reproduction signal has no DC component. This is advantageous because it does not burden the data decoding and servo.

  5 and 6, the high-frequency portion 301 and the low-frequency portion 302 are connected so as to rise at the channel bit switching point. However, at this time, since a phase jump occurs with a probability of 50%, a high frequency component is generated, and the power efficiency per frequency is deteriorated. FIG. 7 shows an example in which the high frequency portion 301 and the low frequency portion 302 are arranged so that the phase continuity is maintained at the channel bit switching point of the meandering groove region 221 in order to improve such a problem. That is, the start phase of the low frequency portion 304 is selected so that the end of the high frequency portion 305 and the start of the low frequency portion 304 are in the same phase direction. The reverse is also true, and the start phase of the high frequency portion 305 is selected so that the end of the low frequency portion 304 and the start of the high frequency portion 305 are in the same phase direction. With this selection, phase continuity is maintained, power efficiency is improved, and the reproduction envelope is constant, so that the data error rate of the information record carrier 1 is improved.

  The frequency of the high frequency portion 301 and the low frequency portion 302 can be selected arbitrarily. However, in order to avoid interference with the frequency band in which the user records data on the information record carrier 1, the high frequency portion 301 is divided into the low frequency portion 302. Compared to, it is required that the frequency is not significantly higher. On the other hand, in order to improve the reproduction error rate of the address data, it is desirable that the frequency difference between the high-frequency portion 301 and the low-frequency portion 302 has a certain degree and the separation property is kept good. From these viewpoints, the frequency ratio (high frequency / low frequency) of the high frequency portion 301 and the low frequency portion 302 is in the range of 1.05 to 5.0, particularly in the range of 1.09 to 1.67. It is desirable. In other words, the phase relationship between the two frequencies is in the range of 2π ± (π / 20.5) to ± (π / 0.75), particularly 2π ± (π / 12) to 2π when the reference phase is 2π. A range of ± (π / 2) (that is, 360 ± 15 degrees to ± 90 degrees) is desirable.

  Of these, in particular, when the frequency ratio (high frequency / low frequency) is 1.5 times as shown in the example of FIG. 7, the two frequencies have a single wave phase of −π / 2.5 (high frequency). And a phase relationship shifted to + π / 2.5 (low frequency) (that is, 2π ± (π / 2.5) when the reference phase is 2π). In other words, the relationship is shifted to 360 ± 72 degrees. These two frequencies can be expressed by integer multiples (here, triple and double) of a single frequency (here 0.5). Therefore, there is an advantage that the demodulation circuit can be simplified. A circuit having a window of 0.5 also facilitates clock generation. Demodulation can also be performed by a synchronous detection circuit, in which case the error rate can be significantly reduced.

  As described above, the information recording carrier 1 according to the present invention includes at least the track 201 (201, 211, 221) having the meandering groove region and the track 203 having the groove portion 202 and at least the linear groove region. These are formed substantially parallel to each other macroscopically and alternately with each other to constitute a parallel groove continuous body 100. The pitch between the center of the track 201 having the meandering groove region and the center of the track 203 having the straight groove region is P, the wavelength of the reproduction light for reproducing the information recording carrier 1 according to the present invention is λ, and the objective lens When the numerical aperture of NA is NA, P <λ / NA is established. Of these, the groove 201 (201, 211, 221) having a meandering region meanders by frequency shift modulation, and its planar structure has a high frequency portion 301 (301, 303, 305) and a low frequency portion 300 (300, 302). , 304).

  Thus, digital data is recorded on the information record carrier 1 according to the present invention by frequency shift modulation. Corresponding to the change of the meandering frequency, 0 and 1 are recorded, so that the discrimination ability of 0 and 1 is excellent. In particular, it does not include minute phase information as in phase shift modulation employed in writable DVDs, so a low error rate can be obtained even with a relatively small C / N. Even if a recording mark is recorded in the groove track (201 and 203) or between the grooves 202 and noise is superimposed, the data meanderingly recorded in the groove track in advance is not disturbed.

  As for mutual interference (crosstalk) between adjacent groove data, the linear groove 203 is inserted between the grooves 201 (201, 211, 221) having meandering regions. There is no address crosstalk. Therefore, almost no data error occurs due to crosstalk, and the address error rate can be kept low even for a pattern in which the distance to the adjacent track changes instantaneously, such as CLV.

  The configuration and effects of the information record carrier 1 according to the present invention have been frequently described above. The present invention is not limited to the information record carrier 1 illustrated in FIGS. 1 to 7, and various modifications and applications can be made in accordance with the gist of the present invention. For example, in the description of frequency shift modulation using FIGS. 5 to 7, a sine wave is used as a fundamental wave, but a cosine wave may be used as a fundamental wave.

  In the present invention, a track 201 having at least a meandering groove region, an inter-groove portion 202, and a track 203 having at least a straight groove region are alternately formed, and the meandering groove region is constituted by at least frequency shift modulation. An information record carrier 1 is provided, and there are various ways to apply it to a disc-shaped information record carrier. For example, as described above, the information recording carrier may be configured such that these tracks are concentrically formed and have a large number of tracks that are self-closed at 360 degrees. Further, the information recording carrier may be configured such that these tracks are formed in a spiral shape and the track 201, the inter-groove portion 202, and the track 203 are not overlapped or connected to each other. At this time, the entire information record carrier is composed of three spirals of a track 201, a groove portion 202, and a track 203. Further, as a modification of the pattern, an information record carrier configured such that the meandering groove region and the linear groove region are reversed at predetermined angles may be used.

  Further, for example, in the description so far, the recording method has been described using the method of directly recording data as it is, but the present invention is not limited to this direct recording. That is, in direct recording, when a long address data string is recorded, 0 may continue or 1 may continue, and a DC component may occur in the data. In order to avoid this, a method may be adopted in which data is recorded after baseband modulation. That is, 0 and 1 are replaced with another code in advance, and the continuation of 0 and 1 is made a certain value or less. As such a method, Manchester code, PE modulation, MFM modulation, M2 modulation, NRZI modulation, NRZ modulation, RZ modulation, differential modulation, etc. can be used alone or in combination.

  As a baseband modulation method particularly suitable for the information record carrier 1 according to the present invention, there is a Manchester code (biphase modulation, two-phase modulation). In this method, 2 bits are applied to 1 bit of data to be recorded as shown in FIG. That is, 00 or 11 is assigned to data 0 to be recorded, and 01 or 10 is assigned to data 1. When connecting data, it is necessary to start from the inverted code of the previous code.

  As described in FIG. 9, the address data “100001” becomes a code string “010011001101”. The original address data is asymmetric data in which four consecutive 0s are included, and the occurrence probability of 0 is twice that of 1. On the other hand, when modulation is performed, the maximum number of consecutive 0s or 1s is two, and the appearance probabilities of 0s and 1s are converted into equal symmetrical data. The baseband modulation in which the continuation of the same bit is limited to a certain value or less as described above has an effect of improving the stability of reading, and is therefore a preprocess suitable for handling long address data.

  There is also a method in which address data is highly decomposed and distributedly recorded. For example, as a first embodiment of distributed address recording, a recording method in which data is recorded in combination with data “101X” (X is 0 or 1) in combination with dummy data “101”, and this data string is arranged at regular intervals. There is. That is, as shown in FIG. 18, “101” is arranged at regular intervals (here, every 11 bits) as data trigger Tr, and X is arranged subsequently. That is, data can be restored by extracting “X” immediately after the data trigger Tr with “101” as the data trigger Tr. In this example, if “1” is considered as data, it can be restored in the order of data presence, absence, and presence, so that “101” can be reproduced as address information. This method is effective for a format in which a data string to be handled may be read over time. Here, it is assumed that 1-bit data extracted at regular intervals is defined as a word, and the word is integrated to form address information.

  In other words, the data recorded by frequency shift keying is address information, and is composed at least of data triggers provided at regular intervals and data assigned to predetermined positions between the data triggers. This is an information record carrier on which address information is recorded depending on the presence or absence of this data.

  As a modification of this method, as shown in FIG. 19, the data trigger Tr and the data may be formed apart by a predetermined bit interval (second embodiment of address distributed recording). Here, the data trigger Tr is “11”, which is arranged every 11 bits. Data is recorded at regular intervals with or without “101”. That is, 1-bit data is restored by taking in data from the fourth bit to the sixth bit following the data trigger Tr. it can. In this example, since data can be restored in the order of presence, absence, and existence, “101” can be reproduced as address information. In this recording method, since the data trigger Tr and the data are separated, reading errors can be reduced.

  As a third example of highly distributed recording, a first specific data pattern (for example, “11”) is arranged (recorded) at regular intervals. Then, the second specific data pattern (for example, “101”) is arranged between the first specific data patterns. The position where the second specific data pattern is arranged is a position advanced by predetermined bits (distance, time) with respect to the first specific data pattern, and in particular, two positions are assigned. That is, as shown in the example of FIG. 20 (third embodiment of address distribution recording), as the first specific data pattern, the data trigger Tr “11” is arranged at regular intervals (here, every 11 bits). The second specific data pattern “101” is arranged in the area. There are two arrangement positions of the second specific data pattern, from the third bit to the fifth bit, or from the fifth bit to the seventh bit, and it is decoded by determining which position is arranged. I do. In this example, since the third bit start, the fifth bit start, and the third bit start are arranged in this order, “101” can be reproduced as the address information. Since this recording method can add whether or not the data “101” can be read as one of the criteria for determining reliability, it is particularly effective when address information is desired to have high reliability.

  In other words, the data recorded by frequency shift keying is address information, and is composed at least of data triggers provided at regular intervals and data assigned to predetermined positions between the data triggers. This is an information record carrier on which address information is recorded according to the relative distance between the data trigger and the data.

  In the description of the third example of the highly distributed recording, the distributed recording method using the position difference using the first specific data pattern and the second specific data pattern has been described. When a pattern with extremely high reading accuracy can be prepared, the first specific data pattern and the second specific data pattern may be the same. That is, for a specific data pattern recorded at a constant time interval, a specific pattern shorter than the time interval may be extracted, and further, the distance interval (time interval) may be measured for decoding. Specifically, as in the fourth embodiment of address distribution recording shown in FIG. 21, for example, the data trigger Tr “11” is arranged at regular intervals (here, every 11 bits) as the first specific data pattern. In the meantime, the second specific data pattern “11” which is common to Tr is arranged. There are two arrangements of the second specific data pattern, the 3rd to 5th bits, or the 5th to 7th bits, and it is determined which position is arranged. Decrypt. In this example, since the third bit start, the fifth bit start, and the third bit start are arranged in this order, “101” can be reproduced as the address information. This recording method has an advantage that the reproducing circuit can be simplified because only one specific data pattern needs to be prepared.

  Heretofore, various types of highly dispersed recording have been described. That is, according to this recording method, the address information is recorded as data broken down bit by bit (in any method). Specifically, first, dummy data of about several bits is prepared as a data trigger Tr. Subsequently, a data string composed of a series of single data (for example, a series of 0) is prepared, and once connected by a single data string so that the data triggers Tr are arranged at regular intervals. The address information broken down bit by bit is recorded so that a part of a single data string is converted according to a predetermined rule. That is, the bit at a position advanced by a predetermined distance from the data trigger Tr is converted by a predetermined rule and recorded.

  On the other hand, during reproduction, data triggers Tr arranged at regular intervals are detected from a data sequence of frequency shift modulation. Then, from the data excluding the data trigger Tr, 1-bit data (corresponding to “word” in FIGS. 18 to 21) is extracted by collating with a predetermined rule. The extracted 1-bit data is accumulated to restore the address information.

  Note that since data recorded in a meandering manner can handle a relatively large amount of data even in a distributed recording method, not only address data but also other sub information can be handled. For example, the type of the information record carrier, the size of the information record carrier, the assumed recording capacity of the information record carrier, the assumed recording linear density of the information record carrier, the assumed recording linear velocity of the information record carrier, the track pitch of the information record carrier, the recording strategy information, Playback power information, manufacturer information, serial number, lot number, management number, copyright related information, key for encryption creation, key for decryption, encrypted data, recording permission code, recording rejection code, Specific data selected at least from a reproduction permission code, a reproduction refusal code, etc. can be mentioned, and an error correction code for these data may be included.

  Further, since the address data is a small amount with respect to the main information, the track 231 having the meandering groove region may be divided into two regions in a macro manner as shown in FIG. That is, a frequency shift modulation area 400 in which address data is recorded and a single modulation area 401 for extracting a clock. Hereinafter, for convenience, the frequency shift modulation area 400 is referred to as an address area 400, and the single modulation area 401 is referred to as a clock area 401. As described above, the former is composed of a high frequency portion and a low frequency portion. The latter is composed only of a constant frequency portion.

  Although the fundamental wave shape and amplitude amount of these two regions may be different, it is desirable that they are the same in view of simplification and stabilization of the recording circuit and the reproducing circuit. Regarding the frequency, the high-frequency portion, the low-frequency portion, and the frequency of the clock region 401 may be different from each other. However, the single frequency of the clock region 401 is the same as either the high-frequency portion or the low-frequency portion. Since the physical length used for clock extraction can be slightly increased, it is easy to perform stable clock extraction, which is advantageous.

  Further, a start bit signal, a stop bit signal, a synchronization signal, etc. for clarifying the division may be recorded at the boundary between these two areas. For example, as an example of such a signal, a single space formed by cutting the track 231 (having the same height as the inter-groove portion 232), an alternating repeating pattern of pits and spaces, or the like is appropriate. In FIG. 10, the shape of the fundamental wave of the clock domain 401 is a sine wave. However, since the clock can be stably extracted in the reproduction of the clock domain and there is no leakage of high-frequency components to user data recording, it is preferable. Can be used. The shape of the fundamental wave in the clock region 401 may be a cosine wave.

  Further, a single frequency for clock may be superimposed and recorded on the frequency shift modulation area 400. That is, a frequency different from either the high frequency side or the low frequency side constituting the frequency shift modulation address may be superimposed. Further, either the high frequency side or the low frequency side may be superimposed on the frequency shift modulation address. Similarly, an integer multiple of one of the frequencies on the high frequency side or the low frequency side, or a frequency that is a fraction of an integer may be superimposed.

  As described above, even if the clock frequency is superimposed on the frequency shift modulation address, the frequency can be separated by a known bandpass filter. Therefore, the address and the clock can be separated and reproduced separately. Therefore, even if the frequency shift modulation region 400 is formed over a long distance, the clock can be extracted continuously, and thus stable reproduction is possible.

  Next, as another application of the information record carrier 1 according to the present invention, application to a light-transmitting layer incident type information record carrier developed in recent years will be described. Unlike the conventional information record carrier, the light-transmitting layer incident type information record carrier has a very thin light-transmitting layer having a thickness of about 0.1 mm with respect to the total thickness of 1.2 mm. Alternatively, recording or reproduction is performed by irradiating reproduction laser light. With such a structure, a high numerical aperture NA can be handled, and the recording density can be increased.

  FIG. 11 schematically shows a cross-sectional structure of the light-transmitting layer incident type information recording carrier 1 and a reproducing method. The light transmitting layer incident type information recording carrier 1 includes at least a support 13, a recording layer 12, and a light transmitting layer 11. On the side of the support 13 in contact with the recording layer 12, the above-described fine pattern made of the groove G or land L is formed. The laser beam 91 responsible for recording or reproduction is incident from the light transmitting layer 11 side through the objective lens 90. The light that has passed through the light-transmitting layer 11 is applied to the recording layer 12, and reproduction or recording / reproduction is performed. In the conventional information record carrier, light is irradiated from the support 13 side, but in the light transmitting layer incident type information record carrier 1, the incident direction is opposite. The names of the groove G and the land L are, according to the definition of JIS (Japanese Industrial Standard), the groove L is a groove closer to the incident surface, and the land L is a groove farther from the incident surface (for example, JIS- X6271-1991). In FIG. 11, the positions of the groove G and the land L are illustrated according to this definition, and the laser beam 91 is irradiated on the groove G side in this example.

  When the address recording described above is applied to the information record carrier 1 having such a configuration, the track 201 having the above-described meandering groove region and the track 203 having the linear groove region on the groove G and the land L, It was examined which of the groove portions 202 is suitable. This problem is deeply related not only to address data but also to whether the recording is to be performed on either the groove G or the land L for the user to record / reproduce on the recording layer 12. When considering from such a viewpoint, the user recording on the recording layer 12 is selectively recorded only in the groove G, so that the reproduction jitter and error rate can be suppressed low, and the recording repeatability is also excellent. found. This is because the groove G is positioned closer to (close to) the laser beam 91 (objective lens 90 side) than the land L, so that the groove G is irradiated with the heat of the laser beam 91 from the land L. Is easy to accumulate. As a result, not only the recording sensitivity in the groove G becomes high, but also the shape of the recording mark formed thereon becomes uniform, and thus it has been found that the groove G can perform ideal recording. On the other hand, when a similar mark is recorded on the land L, the heat generated by the laser light 91 is more easily dissipated than the groove G, and therefore the shape of the recording mark formed there is uneven. This is because it has been found that L cannot perform ideal recording.

  When recording / reproduction is limited to the groove G in this way, the track 201 having the meandering groove region (and the track 203 having the straight groove region) is arranged on the land L side, and the groove portion 202 is arranged on the groove G side. It turned out to be appropriate to arrange. That is, if this configuration is reversed, the center of the track 201 having the meandering groove region is irradiated with the laser beam 91, and the address is reproduced with an output about twice that of the case where the address is arranged on the land L side. The However, in the next track, the laser beam is also irradiated to the center of the track 203 having the linear groove region, and the address is not reproduced at all. Therefore, only one address is reproduced every two rounds, and it is not useful as the address of the information record carrier 1.

  Here, the difference between the height of the groove G and the land L (in other words, the height of the fine pattern) is preferably λ / 8n to λ / 20n in consideration of the push-pull reproduction. Here, n is the refractive index at λ of the translucent layer 11. In particular, since the reflectance of the recording layer 12 decreases due to the presence of the fine pattern 20, it is desirable that the depth of the land L is shallow, and a limit of λ / 10n or less is appropriate as a limit for not deteriorating the jitter of the reproduction signal. Further, since the output of the push-pull signal at the time of tracking increases with the depth of the land L, λ / 18n or more is appropriate as a limit value capable of tracking. That is, λ / 10n to λ / 18n is preferable.

  Further, when the interval between the track 201 having the meandering groove region and the track 203 having the linear groove region is the pitch P (the interval between the groove portion 202 and the groove portion 202 is also the pitch P), the reproduction spot diameter S On the other hand, the relationship of P ≦ S is satisfied. Here, the reproduction spot diameter S is calculated as S = λ / NA from the wavelength λ of the laser beam used for reproduction and the numerical aperture NA of the objective lens. In other words, the pitch P satisfies the relationship P ≦ λ / NA. For example, when the blue-violet laser described above is used, λ is in the range of 350 to 450 nm, and when a high NA lens is used, the NA is 0.75 to 0.9. Therefore, the pitch P is set to 250 to 600 nm. Further, in consideration of recording a digital image by HDTV (High Definition Television) for about 2 hours, the pitch P is preferably 250 to 450 nm. In particular, when NA is 0.85 to 0.9, 250 to 400 nm is particularly desirable. In particular, when NA is 0.85 to 0.9 and λ is 350 to 410 nm, 250 to 360 nm is particularly desirable.

  As a signal system used for recording on the recording layer 12, that is, user recording, for example, a modulation signal called a so-called (d, k) code can be used. The (d, k) modulation signal can be a fixed length code or a variable length code. For example, as an example of (d, k) modulation of a fixed length code, EFM, EFM plus (8-16 modulation) with d = 2 and k = 10, and a modulation signal (D8-15) described in Japanese Patent Laid-Open No. 2000-286709. Modulation), D1, 7 modulation (described in Japanese Patent Application No. 2001-80205) with d = 1 and k = 7, and modulation signal (D4, 6 modulation) described in Japanese Patent Application Laid-Open No. 2000-332613 with d = 1, k = 9. , D = 3, and k = 17 (3, 17) modulation. Further, as an example of (d, k) modulation of a variable length code, a modulated signal (1, 7PP modulation) described in JP-A-11-346154 with d = 1 and k = 7, d = 4 and k = 21. (4, 21) modulation or the like can be suitably used.

  Accordingly, the sectional structure and reproducing method of the information recording carrier 1 according to the present invention are as shown in FIGS. FIG. 13 illustrates a cross-sectional structure of the information recording carrier 1 according to the present invention, which includes at least a support 13, a recording layer 12, and a light transmitting layer 11. Here, the disk-shaped information recording carrier is illustrated as a cross-sectional view cut in the radial direction. The fine pattern (FIG. 4) described above is formed on the side of the support 13 in contact with the recording layer 12. In particular, the track 201 having the meandering groove region and the track 203 having the linear groove region are on the land L side. The groove portion 202 is arranged on the groove G side.

  The laser beam 91 responsible for recording or reproduction is incident from the light transmitting layer 11 side through the objective lens 90. The light that has passed through the light-transmitting layer 11 is applied to the recording layer 12, and reproduction or recording / reproduction is performed.

  FIG. 12 is a plan view of the fine pattern 100 for explaining the reproducing method. Accordingly, the track 201 having the meandering groove region and the track 203 having the straight groove region are alternately arranged, and an inter-groove portion 202 is provided therebetween. Note that the cross-sectional view shown in FIG. 13 is a cross-sectional view of FIG. 12 taken along line segment CR. The track 201 having the meandering groove region, the track 203 having the straight groove region, and the inter-groove portion 202 are substantially parallel to each other, and extend in a direction perpendicular to the radial direction and parallel to the tangential direction. In FIG. 12, the reproduction laser beam 91 is also illustrated, and the spot is focused on the groove portion 202 (groove G side), and reproduction or recording / reproduction can be performed. The reproduction laser beam 91 simultaneously irradiates the wall surfaces of both the track 201 having the meandering groove region and the track 203 having the linear groove region. Therefore, even if recording / reproduction is performed on the inter-groove portion 202, the frequency shift modulation signal can be reproduced by the push-pull method.

  That is, a push-pull signal can be generated by appropriately selecting an output difference of a four-divided photodetector incorporated in a reproduction pickup (not shown). The laser beam 91 of FIG. 12 is projected with four photo-detectors as A, B, C, and D. For example, by generating an output difference in the radial direction, that is, (A + B) − (C + D) A pull signal is obtained. As a result, it is possible to satisfactorily reproduce the data subjected to frequency shift modulation.

  At the same time, this push-pull signal knows whether the data is recorded on the right side or the left side (in the case of a disc-shaped information record carrier, on the inner or outer side) with respect to the inter-groove portion 202. It also becomes a means. For example, the (A + B) signal and the (C + D) signal are compared, and the side on which the reproduction output fluctuates can be determined as the recording side. This has a strong effect when data recording is adapted to address recording. That is, in the information recording carrier 1 according to the present invention, the address data is alternately recorded with the track 203 having the linear groove region, so that the address is output only for one track per two tracks. However, if the push-pull signal can determine whether the data is recorded on the right side or the left side (in the case of a disc-shaped information record carrier, the inner circumference side or the outer circumference side), new binary information can be stored. Therefore, one track address can be obtained for one track.

  FIG. 14 illustrates a method for reproducing such address information for the fine pattern 132 formed on the information record carrier 1. The fine pattern 132 is macroscopically divided into two areas, and includes a clock area 401 for extracting a clock and an address area 400 in which address data is recorded. The latter is composed of a high frequency portion and a low frequency portion.

  The basic planar structure of FIG. 14 is the same as FIG. The reproduction light 91 traces the track from the bottom to the top as shown in FIG. That is, first track 1 (Tr1, 232) is traced, and then track 2 (Tr2, 232) is traced. At this time, by using the (A + B)-(C + D) signal, a signal recorded in the groove 231 having the meandering region can be obtained, but as it is, the track 1 (Tr1, 232), the track 2 (Tr2, 232) The same signal is output in both cases. Therefore, it is not known from the (A + B)-(C + D) signal alone whether the odd track or the even track is being traced.

  However, here, if the determination means for comparing the (A + B) signal with the (C + D) signal and determining the side where the reproduction output fluctuates at a constant period is the recording side, it is determined whether the track is an odd track or an even track. The track can be specified. In the case of FIG. 14, when Tr1 is reproduced as a result of the determination, a signal sequence of right 0, 1, 0, 1, 1 is obtained, and when Tr2 is reproduced, left 0, 1, 0, 1, 1 is obtained. Is obtained. By using such a reproduction method, the address and the track can be uniquely determined. Such even / odd track determination is not necessarily performed in the address area 400. Since it is continuous with the clock region 401, the determination may be made in the clock region 401 before or after the address region 400 is read.

  Further, in addition to the address area 400 and the clock area 401, the determination may be performed using, for example, a track even / odd determination pit provided separately. The determination means at this time is not limited to the comparison between the (A + B) signal and the (C + D) signal because it changes depending on the arrangement of pits and the type of recording code.

  Now, the support 13, the recording layer 12, and the light transmitting layer 11 in FIG. 13 will be described in detail. The support 13 is a base having a function of mechanically holding the recording layer 12 and the light transmitting layer 11 formed thereon. As this material, synthetic resin, ceramic, or metal is used. Typical examples of synthetic resins include polycarbonate, polymethyl methacrylate, polystyrene, polycarbonate / polystyrene copolymers, polyvinyl chloride, alicyclic polyolefin, polymethylpentene, and other thermoplastic resins, thermosetting resins, and various energy ray curable resins. (Including examples of ultraviolet curable resins, visible light curable resins, and electron beam curable resins) can be suitably used. In addition, these may be a synthetic resin blended with metal powder or ceramic powder.

  As typical examples of ceramic, soda lime glass, soda aluminosilicate glass, borosilicate glass, quartz glass, and the like can be used. In addition, as a typical example of the metal, a metal plate having no translucency such as aluminum can be used. The thickness of the support 13 is preferably 0.3 to 3 mm, and more preferably 0.5 to 2 mm because of the necessity of mechanically holding it. Further, when the information recording carrier 1 has a disk shape, the support 13, the recording layer 12, the light transmitting layer 11, etc. are supported so that the total thickness is 1.2 mm for compatibility with the conventional optical disc. It is desirable to design the thickness of the body 13.

  The recording layer 12 is a thin film layer having a function of reading information or recording or rewriting information. As the material of the recording layer 12, a Kerr rotation angle before and after recording represented by a material that causes a change in reflectance and / or a refractive index before and after recording represented by a phase change material, or a magneto-optical material. A material that causes a change, or a material that causes a change in refractive index and / or depth before and after recording, represented by a dye material, is used.

  Specific examples of phase change materials include alloys such as indium, antimony, tellurium, selenium, germanium, bismuth, vanadium, gallium, platinum, gold, silver, copper, aluminum, silicon, palladium, tin, and arsenic. In particular, alloys such as GeSbTe, AgInTeSb, CuAlSbTe, and AgAlSbTe are suitable. As a trace additive element to these alloys, Cu, Ba, Co, Cr, Ni, Pt, Si, Sr, Au, Cd, Li, Mo, Mn, Zn, Fe, Pb, Na, Cs, Ga, Pd, Bi, Containing at least one element selected from the group consisting of Sn, Ti, V, Ge, Se, S, As, Tl, In, Pd, Pt, and Ni in a total of 0.01 atomic% or more and less than 10 atomic%. You can also.

The composition of each element is, for example, Ge ₂ Sb ₂ Te ₅ , Ge ₁ Sb ₂ Te ₄ , Ge ₈ Sb ₆₉ Te ₂₃ , Ge ₈ Sb ₇₄ Te ₁₈ , Ge ₅ Sb ₇₁ Te ₂₄ , Ge ₅ Sb ₇₆ as a GeSbTe system. Te ₁₉ , Ge ₁₀ Sb ₆₈ Te ₂₂ , Ge ₁₀ Sb ₇₂ Te ₁₈ are available, and there are systems in which metals such as Sn and In are added to the GeSbTe system. As the AgInSbTe system, Ag ₄ In ₄ Sb ₆₆ Te ₂₆ and Ag ₄ In ₄ Sb ₆₄ Te ₂₈ , Ag ₂ In ₆ Sb ₆₄ Te ₂₈ , Ag ₃ In ₅ Sb ₆₄ Te ₂₈ , Ag ₂ In ₆ Sb ₆₆ Te ₂₆ , AgInSbTe series metals and semiconductors such as Cu, Fe, and Ge were added. There is a system. CuAlSbTe system,
There is an AgAlSbTe system.

  Specific examples of the magneto-optical material include terbium, cobalt, iron, gadolinium, chromium, neodymium, dysprosium, bismuth, palladium, samarium, holmium, proseodymium, manganese, titanium, palladium, erbium, ytterbium, lutetium and tin. Alloys (alloys include examples of oxides, nitrides, carbides, sulfides, fluorides) can be used, and are composed of alloys of transition metals and rare earths as represented by TbFeCo, GdFeCo, DyFeCo, etc. It is preferable to do this. Further, the recording layer 12 may be formed by using an alternate laminated film of cobalt and platinum.

  Specific examples of the dye material include porphyrin dyes, cyanine dyes, phthalocyanine dyes, naphthalocyanine dyes, azo dyes, naphthoquinone dyes, fulgide dyes, polymethine dyes, acridine dyes, and the like.

  In addition to the materials responsible for recording, the recording layer 12 may include or be laminated with an auxiliary material for the purpose of enhancing recording performance or reproduction performance. For example, as auxiliary materials, alloys such as silicon, tantalum, zinc, magnesium, calcium, aluminum, chromium, zirconium (including oxides, nitrides, carbides, sulfides, fluorides) and highly reflective films (aluminum, gold, etc.) Further, a heat sink material such as silver or various alloys containing one or more of these may be used in combination. In particular, when the recording layer 12 is a phase change material, for example, a dielectric material such as ZnS, SiO, SiN, SiC, AlO, AlN, MgF, and ZrO is laminated on the above-described recording material to obtain an appropriate reflectance. (For example, the reflectance is 12 to 24%), and the amount of reproduction light can be increased, and the number of rewrites, reproduction characteristics, recording characteristics, reproduction stability, and storage stability can be improved.

  The light transmissive layer 11 has a function of guiding the converged reproduction light to the recording layer 12 with a small optical distortion. For example, a material having a transmittance of 70% or more, desirably 80% or more at the reproduction wavelength λ can be suitably used. The light-transmitting layer 11 needs to have little optical anisotropy, and specifically, in order to suppress a decrease in reproduction light, birefringence is specifically ± 100 nm or less in a 90 degree (vertical) incident double pass. Preferably, a material having a thickness of ± 50 nm or less is used. As materials having such characteristics, synthetic resins such as polycarbonate, polymethyl methacrylate, cellulose triacetate, cellulose diacetate, polystyrene, polycarbonate / polystyrene copolymer, polyvinyl chloride, alicyclic polyolefin, and polymethylpentene may be used. it can.

  The light transmissive layer 11 may have a function of mechanically and chemically protecting the recording layer 12. As a material having such a function, a material having high rigidity can be used. For example, transparent ceramic (for example, soda lime glass, soda aluminosilicate glass, borosilicate glass, quartz glass), thermosetting resin, energy ray curable resin (For example, ultraviolet curable resin, visible light curable resin, electron beam curable resin) is preferably used. The thickness of the translucent layer 11 is preferably 2 mm or less, particularly 1.2 mm or less from the viewpoint of reducing birefringence (optical anisotropy). When the information recording carrier reproducing apparatus is used with an NA of 0.7 or more, it is preferably 0.4 mm or less from the viewpoint of suppressing optical aberration when the information recording carrier 1 is tilted. In the case of 85 or more, it is preferably 0.12 mm or less. Further, from the viewpoint of preventing scratches on the recording layer 12, 0.02 mm or more is desirable. That is, a desirable range when NA is 0.85 or more is a range of 0.02 to 0.12 mm. Further, the variation in the thickness of one surface is desirably ± 0.003 mm at maximum because the NA of the objective lens is large. In particular, when the objective lens NA is 0.85 or more, it is desirably ± 0.002 mm or less. Further, particularly when the objective lens NA is 0.9, it is desirably ± 0.001 mm or less.

The translucent layer 11 is not limited to a single layer structure as shown in FIG.
Although not shown, a known antistatic layer, lubricating layer, hard coat layer, or the like may be formed on the side of the light transmitting layer 11 opposite to the recording layer 12. As a specific material for the lubrication layer, a liquid lubricant in which surface energy is adjusted by modifying silicon or fluorine on a hydrocarbon polymer can be used. The thickness of the lubricating layer is preferably about 0.1 nm to 10 nm.
Specific materials for the hard coat layer include thermosetting resins that transmit 70% or more of light of wavelength λ, various energy ray curable resins (ultraviolet curable resins, visible light curable resins, and electron beam curable resins). ), A moisture curable resin, a multi-component mixed curable resin, and a solvent-containing thermoplastic resin.

  In addition, it is desirable that the hard coat layer has a pencil scratch test value of JIS standard K5400 having a certain value or more in consideration of the abrasion resistance of the light transmissive layer 11. The hardest material of the objective lens of the information record carrier reproducing apparatus is glass. In consideration of this, the pencil scratch test value of the hard coat layer is particularly preferably H or more. This is because if it is less than this test value, the generation of dust due to scraping of the hard coat layer becomes significant, and the error rate rapidly deteriorates. The thickness of the hard coat layer is preferably 0.001 mm or more in consideration of impact resistance, and is preferably 0.01 mm or less in consideration of the warp of the entire information recording carrier 1.

In addition, as another material of the hard coat layer, light of wavelength λ is transmitted 70% or more, and a simple substance such as carbon, molybdenum, silicon or an alloy thereof (oxide, nitride, sulfide, etc.) having a pencil scratch test value H or more. (Including examples of fluoride and carbide) can also be used (film thickness of 1 to 1000 nm).
Furthermore, although not shown, label printing may be performed on the side of the support 13 opposite to the recording layer 12. For example, various energy ray curable resins (including examples of ultraviolet curable resins, visible light curable resins, and electron beam curable resins) containing various pigments and dyes can be suitably used for the printing material. 0.001 mm or more is desirable, and 0.05 mm or less is desirable in consideration of the warp of the entire information record carriers 1, 2, 3, and 4.

Furthermore, a hologram for recognizing the information record carrier 1 or a fine pattern that can be visually observed may be formed in addition to the predetermined area used for recording.
In addition, the information record carriers 1 to 4 may be configured such that the entire information record carrier is put in a cartridge in order to improve the mounting property to the reproducing device or the recording device and the protection property on handling.
Further, when the information record carriers 1 to 4 are disc-shaped, the size is not limited. For example, the information record carriers 1 to 4 can take various sizes with a diameter of 20 to 400 mm, and have diameters of 30, 32, 35, 41, 51, 60, 65. 80, 88, 120, 130, 200, 300, 356 mm, etc.

  By the way, as another application of the information record carrier 1 according to the present invention, there is a method of adopting a sawtooth wave as a fundamental wave. That is, although not shown in the figure, the sawtooth can take two values: rising slowly, falling steep, rising steep, and falling gently. Since this has little interference with the data recording method of the present invention, multi-value data recording by combination becomes possible. For example, when the frequency shift modulation is binary, quaternary data recording is possible by combination.

  Further, the information record carrier 1 according to the present invention can be expanded to constitute a multilayer stack information record carrier. In particular, in the two-layer information record carrier 1 as shown in FIG. Recording can be frequency shift modulation with a sawtooth wave first type as a fundamental wave, and address recording of the second layer can be frequency shift modulation with a sawtooth wave second type as a fundamental wave. Here, the sawtooth first type refers to, for example, a slow rise and a steep fall, and the sawtooth second type refers to, for example, a steep rise and a gentle fall. With this configuration, when the reproduced push-pull signal is input to the high-band filter and the differential component is extracted, the rising vector and the falling vector are clearly generated, and layer determination can be performed. In other words, the layer determination of the first layer and the second layer can be performed faster than the decoding of the address data, which is advantageous for shortening the access time during recording and reproduction. Note that FIG. 15 is supplemented. This is a cross-sectional view showing a carrier in which the thin light-transmitting layer information recording carrier described in FIG. Although the description common to FIG. 11 is omitted, the information record carrier 1 is laminated in the order of the support 13, the first recording layer 17, the first light transmitting layer 16, the second recording layer 15, and the second light transmitting layer 14. Yes. The functions and constituent materials of the first recording layer 17 and the second recording layer 15 and the functions and constituent materials of the first light transmitting layer 16 and the second light transmitting layer 14 are the same as the recording layer 12 and the light transmitting layer described in FIG. The 11 functions and constituent materials are basically the same. However, a material in which each constituent material is optimized so that the laser 91 can be transmitted through the second recording layer 15 and recorded on the first recording layer 17 is used.

  Next, examples of the present invention will be described.

Example 1
A disc-shaped information recording carrier 1 having the structure shown in FIG. 10 was produced. The pitch P of the track 231 having the meandering groove region and the track 233 having the straight groove region is 0.32 μm, the width of each groove is 0.16 μm, and the width of the inter-groove portion 232 is 0.16 μm. The track 231 having the meandering groove region and the track 233 having the straight groove region are arranged in the land portion L of FIG. 11, and the inter-groove portion 232 is arranged in the groove portion G. The track 231 having the meandering groove region is composed of only the address region 400 (length 5.5 μm) and the clock region 401, and six address regions are arranged per circuit. In both the address area 400 and the clock area 401, the fundamental wave is a sine wave. The track 233 having the linear groove region was a continuous linear groove having a continuous 360 °.

  For the address region 400, as shown in FIG. 7, the phase difference between the high frequency portion 305 and the low frequency portion 304 is ± π / 7.6, and the phase shift continuity is random at the channel bit switching point. Address data was recorded in information units in which one low-frequency partial wave is one channel bit. Note that the frequency of the low frequency portion was matched with the single frequency of the clock region 401. The amplitudes of the high frequency portion 305, the low frequency portion 304, and the clock region 401 are the same. As pre-processing for recording, the address data was subjected to baseband modulation using Manchester code, and further subjected to differential modulation.

  The disc-shaped information record carrier 1 was a phase change rewrite disc having a recording layer 12 containing AgInSbTe as a main recording material, and the information record carrier 1 capable of recording / reproducing through the 0.1 mm translucent layer 11 was completed.

  Such a disk-shaped information recording carrier 1 was irradiated with laser light 91 from a pickup 90 having a wavelength of λ405 nm (gallium nitride light emitting element) and NA of 0.85 to the groove portion G, and user data was recorded and reproduced. First, before recording, a single frequency was read from the clock domain by a push-pull method, and C / N was measured. Then, a good clock signal of 35 dB at C / N could be reproduced without interference of adjacent addresses (RBW 1 kHz). Subsequently, the address area was selectively reproduced by the push-pull method, and the error rate of the address was measured. The error rate was as good as 4.5E-5. Also, the determination on the inner and outer peripheral sides of the address could be performed well.

  Subsequently, user recording was performed on the groove portion 232 of the disc-shaped information recording carrier 1. Specifically, random user data composed of 2T to 8T was recorded 10 times by using a modulation signal (17PP modulation) described in JP-A-11-346154. Here, the shortest mark length (2T) was set to 0.151 μm. When this recorded signal was reproduced, a good error rate with a jitter of 8.7% and an error rate of 4E-6 was obtained. When the error rate of the address was measured again, it was 7E-5, which was a good error rate although a slight increase in error was observed. There was no particular interference between address information and user data. Further, the determination on the inner and outer peripheral sides of the address could be performed satisfactorily without being disturbed.

(Example 2)
A disc-shaped information recording carrier 1 having the structure shown in FIG. 10 was produced. The pitch P of the track 231 having the meandering groove region and the track 233 having the straight groove region is 0.32 μm, the width of each groove is 0.16 μm, and the width of the inter-groove portion 232 is 0.16 μm. The track 231 having the meandering groove region and the track 233 having the straight groove region are arranged in the land portion L of FIG. 11, and the inter-groove portion 232 is arranged in the groove portion G. The track 231 having the meandering groove region is composed of only the address region 400 (length 5.5 μm) and the clock region 401, and six address regions are arranged per circuit. In both the address area 400 and the clock area 401, the fundamental wave is a sine wave. The track 233 having the linear groove region was a continuous linear groove having a continuous 360 °.

  For the address region 400, the phase difference between the high frequency portion and the low frequency portion is ± π / 2.5, and the phase shift continuity is maintained at the channel bit switching point. Address data was recorded in information units with a wave as one channel bit. Note that the frequency of the low frequency portion was matched with the single frequency of the clock region 401. The amplitudes of the high frequency portion 305, the low frequency portion 304, and the clock region 401 are the same. As preprocessing for recording, the address data was subjected to baseband modulation using Manchester code.

The disc-shaped information record carrier 1 was a phase change rewrite disc having a recording layer 12 containing AgInSbTe as a main recording material, and the information record carrier 1 capable of recording / reproducing through the 0.1 mm translucent layer 11 was completed.
Note that the frequency of the low frequency portion was matched with the single frequency of the clock region 401. The amplitudes of the high frequency portion 305, the low frequency portion 304, and the clock region 401 are the same. As preprocessing for recording, the address data was subjected to baseband modulation using Manchester code.

  Such a disk-shaped information recording carrier 1 was irradiated with laser light 91 from a pickup 90 having a wavelength of λ405 nm (gallium nitride light emitting element) and NA of 0.85 to the groove portion G, and user data was recorded and reproduced. First, before recording, a single frequency was read from the clock domain by a push-pull method, and C / N was measured. Then, a good clock signal of 35 dB at C / N could be reproduced without interference of adjacent addresses (RBW 1 kHz). Subsequently, the address area was selectively reproduced by the push-pull method, and the error rate of the address was measured. The error rate was as good as 2.5E-5. Also, the determination on the inner and outer peripheral sides of the address could be performed well.

  Subsequently, user recording was performed on the groove portion 232 of the disc-shaped information recording carrier 1. Specifically, random user data composed of 2T to 10T and 13T (synchronization signal) was recorded 10 times using a modulation signal (D4, 6 modulation) described in Japanese Patent Application No. 2000-80205. Here, the shortest mark length (2T) was set to 0.154 μm. When this recorded signal was reproduced, a good error rate with a jitter of 8.6% and an error rate of 3.5E-6 was obtained. When the error rate of the address was re-measured, it was 3E-5, which was a good error rate although a slight error increase was observed. There was no particular interference between address information and user data. Further, the determination on the inner and outer peripheral sides of the address could be performed satisfactorily without being disturbed.

(Example 3)
A disc-shaped information recording carrier 1 having the structure shown in FIG. 10 was produced. The pitch P of the groove 231 having the meandering region and the linear groove 233 is 0.32 μm, the width of each groove is 0.16 μm, and the width of the inter-groove portion 232 is 0.16 μm. The track 231 having the meandering groove region and the track 233 having the straight groove region are arranged in the land portion L of FIG. 11, and the inter-groove portion 232 is arranged in the groove portion G. The track 231 having the meandering groove region is composed of only the address region 400 (length: 30 μm) and the clock region 401, and three address regions are arranged per circle. In both the address area 400 and the clock area 401, the fundamental wave is a sine wave. The track 233 having the linear groove region was a continuous linear groove having a continuous 360 °.

  For the address region 400, the phase difference between the high-frequency portion and the low-frequency portion is ± π / 11, and the phase continuity at the channel bit switching point is random. Address data was recorded in units of information. Note that the frequency of the high frequency portion was made to coincide with the single frequency of the clock region 401. The amplitudes of the high frequency portion 305, the low frequency portion 304, and the clock region 401 are the same. As preprocessing for recording, the address data was subjected to baseband modulation using Manchester code.

  The disc-shaped information record carrier 1 was a phase change rewrite disc having a recording layer 12 whose main recording material was Ge-doped SbTe, and the information record carrier 1 capable of recording / reproducing through the 0.1 mm translucent layer 11 was completed.

  Such a disk-shaped information recording carrier 1 was irradiated with laser light 91 from a pickup 90 having a wavelength of λ405 nm (gallium nitride light emitting element) and NA of 0.85 to the groove portion G, and user data was recorded and reproduced. First, before recording, a single frequency was read from the clock domain by a push-pull method, and C / N was measured. Then, a good clock signal of 35 dB at C / N could be reproduced without interference of adjacent addresses (RBW 1 kHz). Subsequently, the address area was selectively reproduced by the push-pull method, and the error rate of the address was measured. The error rate was as good as 1E-4. Also, the determination on the inner and outer peripheral sides of the address could be performed well.

  Subsequently, user recording was performed on the groove portion 232 of the disc-shaped information recording carrier 1. Specifically, random user data composed of 3T to 11T and 12T (synchronization signal) was recorded 100 times by using a modulation signal (D8-15 modulation) described in JP-A-2000-286709. Here, the shortest mark length (3T) was set to 0.185 μm. When this recorded signal was reproduced, a good error rate with a jitter of 7.7% and an error rate of 8E-7 was obtained. When the error rate of the address was measured again, it was 2.5E-4, which was a good error rate although a slight error increase was observed. There was no particular interference between address information and user data. Further, the determination on the inner and outer peripheral sides of the address could be performed satisfactorily without being disturbed.

It is a figure which shows the 1st Example of the information record carrier based on this invention. It is a figure which shows the 2nd Example of the information record carrier based on this invention. It is a figure which shows the 3rd Example of the information record carrier based on this invention. It is a figure which shows the planar fine structure of the information record carrier based on this invention. It is a figure which shows the structure of the groove | channel formed in the information recording carrier based on this invention. It is a figure which shows the other structure of the groove | channel formed in the information recording carrier based on this invention. It is a figure which shows other structure of the groove | channel formed in the information recording carrier based on this invention. It is a figure which shows the change of the data before baseband modulation and after baseband modulation. It is a figure which shows the specific example of the change of the data before baseband modulation and after baseband modulation. It is a figure which shows another structure of the groove | channel formed in the information recording carrier based on this invention. It is sectional drawing showing a thin translucent layer information recording carrier. 1 is a plan view showing an information record carrier and a reproducing method thereof according to the present invention. It is sectional drawing showing a thin translucent layer information recording carrier and its reproducing method. 1 is a plan view showing an information record carrier and a reproducing method thereof according to the present invention. FIG. 12 is a cross-sectional view showing a carrier in which the thin light-transmitting layer information recording carrier described in FIG. It is a figure which shows the concept of the phase shift modulation in a rewritable DVD disc. It is a figure which shows the concept of the recording state of the address information in a rewritable DVD disc. It is a figure which shows the specific example of 1st Embodiment of address information dispersion | distribution recording. It is a figure which shows the specific example of 2nd Embodiment of address information dispersion | distribution recording. It is a figure which shows the specific example of 3rd Embodiment of address information dispersion | distribution recording. It is a figure which shows the specific example of 4th Embodiment of address information dispersion | distribution recording.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Information recording carrier 100 Parallel groove | channel continuous body 201,211,221 Serpentine groove | channel 202 Groove part 203,213,223 Straight groove 300,302,304 Low frequency part 301,303,305 High frequency part 400 Frequency shift modulation area (address area) )
401 Single modulation domain (clock domain)

Claims (4)

A support having a fine pattern consisting of concentric or spiral tracks;
A recording layer formed on the fine pattern;
And at least a light-transmitting layer formed on the recording layer,
An information recording carrier for reproducing by irradiating the recording layer with a light beam obtained by condensing a laser beam by an objective lens through the translucent layer,
The track is a continuous track of 360 degrees and has at least a meandering groove region,
The meandering groove region is composed of meandering grooves having a frequency shift modulated wave as a groove waveform shape,
The frequency shift modulated wave is composed of a high-frequency wave and a low-frequency wave, and the frequency of the high-frequency wave and the low-frequency wave so that a value obtained by dividing the frequency of the high-frequency wave by the frequency of the low-frequency wave is 1.5. And the phase of the high frequency wave and the phase of the low frequency wave so that the phase of the high frequency wave and the phase of the low frequency wave are continuous at the switching point between the high frequency wave and the low frequency wave. An information record carrier comprising: selecting a wave phase; and both the amplitude direction of the high frequency wave and the amplitude direction of the low frequency wave are radial directions of the information record carrier. When the wavelength of the laser beam is λ and the numerical aperture of the objective lens is NA,
The pitch P between the tracks has a relationship of P <λ / NA,
When the λ is 405 nm and the NA is 0.85, the thickness of the light transmitting layer is 0.02 to 0.12 mm, and the thickness variation of the light transmitting layer over one surface of the information record carrier is ± 0. 2. The information recording carrier according to claim 1, wherein the information recording carrier has a shape of 002 mm or less. A support having a fine pattern consisting of concentric or spiral tracks;
A recording layer formed on the fine pattern;
And at least a light-transmitting layer formed on the recording layer,
An information recording carrier for reproducing by irradiating the recording layer through the light transmitting layer using a light beam obtained by condensing laser light with an objective lens,
The track is formed by arranging a meandering groove region and a straight groove region in which a straight groove is formed adjacent to each other in the radial direction,
The meandering groove region is composed of a meandering groove having a frequency shift modulated wave based on a rectangular wave as a groove waveform shape,
The frequency shift modulated wave is composed of a high frequency wave and a low frequency wave, and the frequency of the high frequency wave is such that a value obtained by dividing the frequency of the high frequency wave by the frequency of the low frequency wave is 1.05 to 5.0. The phase of the high-frequency wave is selected such that the phase of the high-frequency wave and the phase of the low-frequency wave are continuous at a switching point between the high-frequency wave and the low-frequency wave. And the phase of the low frequency wave, and the amplitude direction of the high frequency wave and the amplitude direction of the low frequency wave are both radial directions of the information record carrier. A method for reproducing an information record carrier for reproducing the information record carrier according to any one of claims 1 to 3,
Irradiating the recording layer with the light beam through the translucent layer;
Generating a push-pull signal based on reflected light from the recording layer of the light beam applied to the recording layer;
And a step of demodulating the frequency shift modulated wave from the push-pull signal.

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