JP2001319371A - Information recording carrier and information recording carrier reproducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high density information recording carrier which exceeds the theoretical reproduction limit and a low-cost information recording carrier reproducer which reproduces the carrier. SOLUTION: The information recording carrier 1 comprises a substrate 2 and an ultra-microscopically discontinuous film 3 formed on the substrate 2. The information recording carrier reproducer 12 has a power driver 16 which supplies reproduction output capable of reading out a pattern which exceeds the theoretical reproduction limit and has been formed in the carrier 1 to a light source for reading out the recorded information of the carrier 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information record carrier and an information record carrier reproducing apparatus for recording / reproducing the information record carrier.

[0002]

2. Description of the Related Art An information recording carrier has been attracting attention as a central player of a recording medium in an advanced information society. In particular, information recording carriers capable of recording and reproducing high-density information at high speed using optical means have been widely used.
For example, as a read-only type information recording carrier using light of a wavelength of 780 nm, a CD on which music information or a program is recorded, a video CD on which image information is recorded, and the like are known. , CD-R, P
D and MO disks.

[0003] The recording density of these information record carriers has been increasingly improved with the advancement of information. The limit of the recording density is determined by the MTF (spatial frequency) of the optical system. This MTF is expressed as λ / 4NA, where λ is the reproduction wavelength and NA is the numerical aperture of the objective lens.
Therefore, in order to increase the recording density, it is necessary to decrease λ and increase NA.

For example, in a read-only DVD (digital versatile disc) released in 1996, λ
Is changed from the conventional 780 nm to 650 nm, and NA is changed from the conventional 0.45 to 0.6.
The detection limit of D was 271 nm in principle. As a result, a recording density approximately seven times as high as that of a CD was achieved in combination with other improved techniques. Such a situation is the same in an information recording carrier for recording / reproducing, such as DVD-R, DVD-RAM,
DVD-RW and DVD + RW have been developed.

Here, a read-only DVD will be specifically described below with reference to FIG. FIG. 10 is a sectional view showing a conventional information recording carrier used for a read-only DVD. First, the configuration of the conventional information recording carrier 21 will be described. A fine pattern 22A is formed on the surface of a transparent substrate 22 made of polycarbonate having a thickness of 0.6 mm. On this fine pattern 22A, a recording layer 23 made of a continuous aluminum film having a thickness of 70 nm, and a recording layer 23 having a thickness of 10 μm are formed.
m, an adhesive layer 24 made of an ultraviolet curable resin, and a thickness of 0.6
mm transparent polycarbonate substrate 25
Are sequentially laminated.

The fine pattern 22A is formed in a spiral shape and constitutes signals of various lengths of 3T to 14T and 14T. The length of the 3T signal, which is the shortest pit, is a pit length of 400 nm, which is 1.47 times the detection limit. In other words, the fine patterns 22A are all composed of signals longer than the detection limit.

The reproduction of the information recording carrier 21 is performed as follows. Reproducing light having a wavelength λ emitted from a light source such as a semiconductor laser is irradiated from the transparent substrate 22 side to generate diffracted light in the fine pattern 22A. Then, after the diffracted light is reflected by the recording layer 23, the reflected light is received by a photodetector (not shown), and an information signal is taken out and reproduced.

[0008]

However, in order to realize an information recording carrier having a higher density than a read-only DVD, it has been studied to make λ shorter and NA larger. There has been a problem that the cost of the information recording carrier reproducing apparatus for reproducing the carrier is significantly higher than the current state. In particular, a great burden is imposed on shortening the wavelength of a semiconductor laser, and for example, development of a semiconductor laser having a wavelength shorter than λ = 400 nm requires a large amount of cost.

For this reason, there has been a demand for an information recording carrier side capable of reducing the cost of an information recording carrier reproducing apparatus for reproducing an information recording carrier having a higher density than a DVD. That is, there is a need for an information record carrier reproducing apparatus for reproducing a signal having a pit length exceeding the theoretical reproduction limit. The present invention has been made in view of the above problems, and an object of the present invention is to provide a high-density information recording carrier exceeding a theoretical reproduction limit and an inexpensive information recording carrier reproducing apparatus for reproducing the same.

[0010]

Means for Solving the Problems A first invention of an information recording carrier according to the present invention comprises a support, a fine pattern formed on the support, and a microscopic pattern laminated on the fine pattern. And a continuous film. The second invention is characterized by comprising at least a support, a microscopic discontinuous film laminated on the support, and a recording layer. According to a third aspect of the present invention, in the information recording carrier according to the second aspect, the recording layer is made of at least one of a highly reflective material, a dye material, a phase change material, and a magneto-optical material. A fourth aspect of the present invention is the information recording carrier according to any one of claims 1, 2 and 3, wherein the microscopic discontinuous film is made of isolated material particles separated from each other, and the planar size of the isolated material particles Is 0.001-0.1μ
m, and the height of the uppermost surface of the isolated material particles;
The difference in the height of the gap between the isolated material particles is 0.1 to 20 nm.
It is characterized by being within the range. A fifth invention is the information recording carrier according to any one of claims 2, 3, and 4, wherein a fine pattern is formed between the support and the microscopic discontinuous film. I do. According to a sixth aspect of the present invention, in the information recording carrier according to the fifth aspect, a plane size of the isolated material particle is smaller than a minimum dimension of the fine pattern. An information record carrier reproducing apparatus according to the present invention includes a pickup having a light source for reading a record signal of an information record carrier, a demodulator for demodulating the record signal and outputting a data stream signal, and an interface for outputting the data stream signal to the outside. An information recording / reproducing apparatus comprising: a power driver for supplying to the light source a reproduction output capable of reading a pattern exceeding a theoretical reproduction limit formed on the information recording carrier.

[0011]

FIG. 1 shows an embodiment of an information record carrier and an information record carrier reproducing apparatus for reproducing the information record carrier according to the present invention.
This will be described with reference to FIGS. The same components as those of the conventional example are denoted by the same reference numerals, and description thereof will be omitted. FIG. 1 is a sectional view showing an information recording carrier according to an embodiment of the present invention. FIG. 2 is a plan view showing the morphology of the microscopic discontinuous film formed on the substrate surface. FIG. 3 is a cross-sectional view near the microscopic discontinuous film in the information recording carrier according to the embodiment of the present invention.
FIG. 4 shows a first example of the information record carrier according to the embodiment of the present invention.
It is sectional drawing which shows a modification. FIG. 5 is a sectional view showing a second modification of the information recording carrier of the embodiment of the present invention. FIG. 6 is a sectional view showing a third modification of the information recording carrier of the embodiment of the present invention. FIG. 7 is a sectional view showing a fourth modification of the information recording carrier of the embodiment of the present invention. FIG. 8 is a sectional view showing a fifth modification of the information recording carrier of the embodiment of the present invention. FIG. 9 is a block diagram showing an information record carrier reproducing apparatus for reproducing the information record carrier of the present invention.

First, an embodiment of the information recording carrier of the present invention will be described below with reference to FIGS. As shown in FIG. 1, an information recording carrier 1 according to an embodiment of the present invention
Is a microscopic discontinuous film 3 formed on the surface of a disk-shaped support 2. The microscopically discontinuous film 3 is a film in which the material constituting the microscopically discontinuous film 3 is not uniform and is discontinuous. The thickness of the support 2 is 0.2 to 3
mm, preferably 0.3 to 2 mm. The material of the support 2 is selected according to the principle of a reproducing apparatus or a recording / reproducing apparatus.

The reproduction light or the recording light is applied to the microscopic discontinuous film 3
When the light is incident from the side, any of synthetic resin, ceramic, and metal can be used as the material of the support 2. When the reproducing light or the recording light is incident from the support 2 side, a synthetic resin or ceramic can be used as a material of the support 2. In this case, in particular, the transmittance at the wavelength λ of the reproduction light or the recording light is 60% or more,
Desirably, a material that is 80% or more is selected.

The above-mentioned synthetic resins include various thermoplastic resins and thermosetting resins such as polycarbonate, polymethyl methacrylate, polystyrene, polycarbonate / polystyrene copolymer, polyvinyl chloride, alicyclic polyolefin, and polymethylpentene. Radiation-curable resins (including examples of ultraviolet-curable resins and visible-light curable resins) are preferred. Here, when the reproduction light or the recording light is incident from the microscopic discontinuous film 3 side, the synthetic resin is
It may be a mixture of metal powder or ceramic powder. Also, soda lime glass as ceramic,
Soda aluminosilicate glass, borosilicate glass, quartz glass, and the like.

A fine pattern 2A is formed on the surface of the support 2, and a microscopic discontinuous film 3 is formed on the fine pattern 2A.
May be formed. The fine pattern 2A is, for example, a group of pits or a group of grooves provided for reproduction. In particular, in the case of a read-only information recording carrier, the carrier is mainly composed of a pit group, and at least the shortest pit length of the modulated signal has a length equal to or less than a reproduction limit, that is, a length equal to or less than λ / 4NA.

Here, the microscopic discontinuous film 3 will be described in detail with reference to FIG. As shown in FIG. 2, when the microscopic discontinuous film 3 is microscopically observed with a transmission electron microscope (TEM), an atomic force microscope (AFM), or the like, the microscopic discontinuous film 3 It shows morphology. That is, it is an aggregate of the isolated material particles 3A microscopically isolated and dispersed.
A appear to be separated from each other.

As shown in FIG. 2, this isolated and dispersed state is a particle aggregate, an ellipsoid aggregate, or an amoeboid amorphous aggregate. Each of the isolated material particles 3A has a plane size (average diameter D) of 0.1 μm or less on average, and can be produced with D = 0.001 to 0.1 μm depending on the material and manufacturing conditions. The gap 3 between the isolated material particles 3A
Regarding B, it is considered that it is either a vacancy or an impurity gas mixed in the production process, but research has not progressed at this stage. At least such a microscopic discontinuous film 3
Is a continuous thin film (thi) with so-called bulk
n film) shows a different refractive index and extinction coefficient.

Although the microscopic discontinuous film 3 is a very thin film, the thickness of the film is the same as the conventional concept of the film thickness because the isolated material particles 3A are isolated and dispersed. Can not adapt. However, as shown in FIG. 3, the top surface S ₀ of the discrete isolated particles, by defining the difference between the surface S ₁ of the support 2 as a thickness H, the thickness H is the 0.1~20nm Range. The calculated film thickness H obtained by performing the area averaging process by regarding the gap 3B as a hole is in a range of approximately 0.01 to 15 nm.

Next, a method of manufacturing the microscopic discontinuous film 3 will be described. Such a microscopic discontinuous film 3 is formed by using any one of a metal, a metal alloy (including examples of oxides, nitrides, carbides, sulfides, and fluorides) and an organic material as a raw material, and reducing this raw material under low pressure. And can be produced by reconstituting on the support 2.

Specifically, in a low-pressure atmosphere containing at least one gas selected from water, hydrogen, oxygen, nitrogen, carbon dioxide, carbon monoxide, helium, argon, neon, xenon, and krypton, It decomposes to form a microscopic discontinuous film 3 on the surface of the support 2. The low pressure is from 10 ^-9 atmosphere to 10 ^-3 atmosphere, preferably from 10 ^-8 atmosphere to 1 atmosphere.
^0-4 atm.

At this time, when the generation time of the microscopic discontinuous film 3 becomes longer, another microscopic discontinuous film 3 is deposited on the microscopic discontinuous film 3, and as a result, It may be a continuous thin film. Therefore, it is necessary to pay attention to the generation time so that the film thickness H falls within the above-mentioned predetermined range.

In the decomposition of the raw material, heating and glow discharge may be used in combination. Regarding the temperature of the support 2, if the temperature is higher than the softening temperature of the support 2, the support 2 is deformed, and the deposited microscopic discontinuous film 3 itself is also undesirably deformed. For this reason, the temperature of the support 2 needs to be lower than the softening temperature of the support 2.

For example, when polycarbonate is used for the support 2, since the softening temperature is 140 ° C., the film is formed below this temperature. Desirable conditions include:
Molybdenum, silicon, germanium, or aluminum is selected as a raw material, and glow discharge is performed at low pressure.
It is preferable that the temperature of the support 2 is set at 10 to 30 ° C.

As a result of examining whether or not reproduction characteristics exceeding the theoretical reproduction limit can be obtained by performing reproduction using such an information recording carrier 1, a pattern (pit or mark) of λ / 4NA or less can be read. all right. That is, reproduction characteristics exceeding the theoretical reproduction limit were obtained. In particular,
When the plane size D of the isolated material particles 3A in the microscopic discontinuous film 3 is sufficiently smaller than the pattern size to be reproduced, a reproduction power higher than the minimum reproduction power at which a pattern exceeding the theoretical reproduction limit can be read is irradiated. Then, reproduction characteristics exceeding the reproduction limit can be obtained.

For example, when the minimum dimension (for example, the shortest pit length and the shortest mark length) of the reproduction pattern is 0.2 μm, the plane size D needs to be 0.1 μm or less. When the size is 0.1 μm, the plane size D needs to be 0.05 μm or less. Here, the pattern size to be reproduced refers to the size of the fine pattern 2A engraved on the support 2 in the case of a read-only type information recording carrier. Refers to the size of a given pattern.

The reason why the reproduction characteristics exceeding the theoretical resolution limit can be obtained by using the microscopic discontinuous film 3 is under investigation. However, since the expression power varies depending on the material and the film forming conditions, This is considered to be the result of physical interaction between the microscopic discontinuous film 3 and the reproduction light. As mentioned above,
When the information recording carrier 1 having the microscopic discontinuous film 3 formed on the support 2 is used, reproduction characteristics exceeding the theoretical resolution limit can be obtained.

Next, a first modification of the embodiment of the present invention will be described with reference to FIG. As shown in FIG. 4, the information recording carrier 4 in the first modification of the embodiment of the present invention has a thickness of 0.003 mm on the microscopic discontinuous film 3 of the information recording carrier 1 in the embodiment of the present invention. The resin layer 5 having a thickness of about 0.3 mm is laminated, and the other configuration is the same.
Examples of the material of the resin layer 5 include a thermosetting resin, various radiation-curable resins (including an ultraviolet-curable resin and a visible-light curable resin), an electron beam-curable resin, a moisture-curable resin, a multi-liquid mixed-curable resin, and a thermoplastic resin (for example, polycarbonate). )and so on.

As in the case of the support 2 described above, when the reproduction light or the recording light is incident from the support 2 side, the transmittance of the resin layer 5 with respect to the wavelength λ of the reproduction light or the recording light is , 60
% Or more, preferably 80% or more.
In this case, the same effects as those of the embodiment of the present invention can be obtained.

Next, a second modification of the embodiment of the present invention will be described with reference to FIG. As shown in FIG. 5, the information recording carrier 6 of the second modification of the embodiment of the present invention is different from the microscopic discontinuous film 3 of the information recording carrier 4 of the first modification.
The recording layer 7 is formed between the resin layer 5 and the resin layer 5 to improve the reflectance, and the other configuration is the same.

As the material of the recording layer 7, a known high reflectance recording material can be used as it is, for example, aluminum, gold, silver, copper, silicon, titanium, chromium, nickel, tantalum, molybdenum, iron, zinc, Metals such as gallium, arsenic, and palladium or alloys thereof (alloys include examples of oxides, nitrides, carbides, sulfides, and fluorides). In particular, aluminum, silver, and gold are suitable. In this case, since the reflectance can be improved in addition to the effects of the embodiment of the present invention, the S / N of the reproduced signal can be improved.

Here, the recording layer 7 may be replaced with a known recording material to enable recording and reproduction.
In this case, the material of the recording layer 7 shown in FIG. 5 includes a dye material, a phase change material, and a magneto-optical material according to the recording or reproducing principle.

At this time, the pattern (not shown) recorded on the recording layer 7 is mainly composed of mark groups, and at least the shortest pit length of the modulation signal is equal to or less than the reproduction limit, that is, equal to or less than λ / 4NA. Have. Examples of the dye material include a cyanine dye, a phthalocyanine dye,
Naphthalocyanine dye, azo dye, naphthoquinone dye,
There are fulgide dye, polymethine dye, acridine dye and the like.

As the above-mentioned phase change material, indium, antimony, tellurium, selenium, germanium, bismuth, vanadium, gallium, platinum, gold, silver, copper, tin,
There are alloys such as arsenic (alloys include examples of oxides, nitrides, carbides, sulfides, and fluorides), particularly GeSbT.
It is preferable to use e, AgInSbTe, CuAlTeSb, or the like. Alternatively, a stacked film of an indium alloy and a tellurium alloy may be used.

The magneto-optical materials described above include terbium, cobalt, iron, gadolinium, chromium, neodymium,
Dysprosium, bismuth, palladium, samarium,
Alloys such as holmium, proseodymium, manganese, titanium, palladium, erbium, ytterbium, lutetium, and tin (alloys are oxides, nitrides, carbides, sulfides,
Including examples of fluorides), especially TbFeCo, Gd
It is preferable to use a transition metal and a rare earth alloy as typified by FeCo and DyFeCo. Alternatively, an alternately laminated film of cobalt and platinum may be used.

Incidentally, these various materials are provided with an auxiliary film, for example, silicon, tantalum, zinc, magnesium, for the purpose of improving the reproduction output, the number of rewritings, and the storage stability.
An alloy (including an oxide, a nitride, or a carbide) of calcium, aluminum, chromium, zirconium, or the like, or a highly reflective film (aluminum, gold, silver, or the like) may be used in combination. In this case, the same effects as those of the embodiment of the present invention can be obtained.

Next, a third modification of the embodiment of the present invention will be described with reference to FIG. As shown in FIG. 6, the information recording carrier 8 of the third modification of the embodiment of the present invention is different from the recording layer 7 of the information recording carrier 6 of the second modification of the present invention shown in FIG. The order of lamination with the continuous film 3 is reversed.

Next, a fourth modification of the embodiment of the present invention will be described with reference to FIG. As shown in FIG. 7, an information recording carrier 9 according to a fourth modification of the embodiment of the present invention has a dummy support for increasing the mechanical strength of the information recording carrier 6 according to the second modification of the present invention shown in FIG. The body 10 is bonded on the resin layer 5. If the dummy support 10 is made of the same material and the same thickness as the support 2, the mechanical balance can be improved in addition to the effects of the embodiment of the present invention.

Next, a fifth modification of the embodiment of the present invention will be described with reference to FIG. As shown in FIG. 8, an information recording carrier 11 according to a fifth modification of the embodiment of the present invention includes:
Information recording carrier 6 in a second modification of the present invention shown in FIG.
Are prepared, and the resin layers 5 are bonded to each other with facing each other. This makes it possible to double the reproduction capacity in addition to the effects of the embodiment of the present invention.

Next, the information recording carrier 1 according to the embodiment of the present invention shown in FIG. 1 is mounted on a reproduction evaluation device, a laser beam is used as the reproduction beam, and the power of the laser beam is changed to change the C / N ratio.
(Carrier / noise) was measured, and it was examined whether a signal exceeding the theoretical reproduction limit could be reproduced. The power of the laser light was changed to 0.8 mW, 1.5 mW, and 0.7 mW. Here, the lowest laser light power at which a pattern equal to or larger than the theoretical reproduction limit can be read is 0.75 mW.

A sample of the information recording carrier 1 was prepared as follows. A support 2 made of polycarbonate having a diameter of 120 mm and a thickness of 0.6 mm is prepared, and a fine pattern 2A composed of a single frequency signal having a pit length of 260 nm is spirally formed on this surface (track pitch 0.74).
μm).

A microscopic discontinuous film 3 made of aluminum is formed on the fine pattern 2A. Specifically, the microscopic discontinuous film 3 is formed by setting the temperature of the support 2 to 30 ° C. and performing glow discharge in a low pressure of 10 ⁻⁴ atm containing argon as a main component of the residual gas. . At this time, the generation time was adjusted so that the plane size D was 0.1 μm and the film thickness H was 2 μm.
It was set to 0 nm. The C / N of the information recording carrier 1 is such that the wavelength λ of the reproduction light (laser light) is 650 nm and the numerical aperture NA is 0.1.
6 using a reproduction evaluation apparatus. The theoretical reproduction limit of this reproduction evaluation device is 271 nm.

(In the case of a power of 0.8 mW) First,
Reproduction was performed with the laser light power set to 0.8 mW. As a result, a single-frequency signal having a pit length of 260 nm was reproduced, and the C / N was 6 dB. Since the reproduction limit of this reproduction evaluation device was 271 nm, it was found that a signal exceeding the theoretical reproduction limit could be reproduced.

(In the case of power of 1.5 mW) Next, reproduction was performed with the laser light power set to 1.5 mW. As a result, a single frequency signal having a pit length of 260 nm can be reproduced,
C / N was 26 dB. That is, it was found that a signal exceeding the theoretical reproduction limit could be reproduced.

(In the case of a power of 0.7 mW) Next, reproduction was performed with the laser beam power set to 0.7 mW. As a result, a single frequency signal having a pit length of 260 nm could not be reproduced at all, and the C / N was 0 dB. That is, it was impossible to reproduce a signal exceeding the theoretical reproduction limit.

(Comparative Example) Here, for comparison, information recording in the case where the laser beam power was set to 1.5 mW and an aluminum continuous film having a thickness of 70 nm instead of the microscopic discontinuous film 3 was used. The C / N of the carrier was examined in the same manner as described above. As a result, a single frequency signal having a pit length of 260 nm could not be reproduced at all, and the C / N was 0 dB. That is, it was impossible to reproduce a signal exceeding the theoretical reproduction limit.

As described above, using the information recording carrier 1 on which the microscopic discontinuous film 3 made of aluminum is formed,
When the information recording carrier 1 is reproduced by irradiating a laser beam having a minimum reproduction power higher than a minimum reproduction power capable of reading a pattern higher than the theoretical reproduction limit, a signal having a pit length exceeding the theoretical reproduction limit can be reproduced.

Next, the first embodiment of the present invention shown in FIG.
The information recording carrier 4 according to the modified example is mounted on a reproduction evaluation device, a laser beam is used as the reproduction beam, and the power of the laser beam is changed to measure the C / N. I checked whether it was possible. The power of the laser light was changed to 0.5 mW, 2 mW, and 0.4 mW. Here, the power of the minimum laser beam from which a pattern exceeding the theoretical reproduction limit can be read is 0.45 mW. At this time, a sample of the information recording carrier 4 was produced as follows.
A support 2 made of polycarbonate having a diameter of 45 mm and a thickness of 0.6 mm was prepared, and a pit length of 220 nm was formed on this surface.
Is formed spirally (track pitch 0.6 μm).

A microscopic discontinuous film 3 made of molybdenum is formed on the fine pattern 2A. In particular,
The microscopic discontinuous film 3 is formed by heating and evaporating the support 2 at a temperature of 10 ° C. and at a low pressure of 10 ⁻⁵ atm with water as a main component of the residual gas. At this time, the generation time was adjusted so that the plane size D was 0.01 μm and the film thickness H was 15 nm. The resin layer 5 was made of an ultraviolet curable resin having a thickness of 8 μm. As described above, the C / N of the information record carrier 4
Was performed using a reproduction evaluation apparatus having a reproduction light (laser light) wavelength λ of 650 nm and a numerical aperture NA of 0.6. As described above, the theoretical playback limit of this playback evaluation device is 27
1 nm.

(In the case of power of 0.5 mW) First,
Reproduction was performed with the laser light power set to 0.5 mW. As a result, a single frequency signal having a pit length of 220 nm was reproduced, and the C / N was 3 dB. Since the reproduction limit of this reproduction evaluation device was 271 nm, it was found that a signal exceeding the theoretical reproduction limit could be reproduced.

(In the case of power of 2 mW) Next, reproduction was performed with the power of the laser beam set to 2 mW. As a result, a single frequency signal having a pit length of 220 nm can be reproduced, and C / N
Was 30 dB. That is, it was found that a signal exceeding the theoretical reproduction limit could be reproduced.

(In the case of power of 0.4 mW) Next, reproduction was performed with the power of the laser beam set to 0.4 mW. As a result, a single frequency signal having a pit length of 220 nm could not be reproduced at all, and the C / N was 0 dB. That is, it was impossible to reproduce a signal exceeding the theoretical reproduction limit.

(Comparative Example) Here, for comparison, the power of the laser beam was set to 2 mW, and the information recording carrier in the case of a 70-nm thick molybdenum continuous film instead of the microscopic discontinuous film 3 was used. C / N was examined in the same manner as above. As a result, a single frequency signal having a pit length of 220 nm could not be reproduced at all, and the C / N was 0 dB. That is, it was impossible to reproduce a signal exceeding the theoretical reproduction limit.

As described above, by using the information recording carrier 4 on which the microscopic discontinuous film 3 made of molybdenum is formed, the information recording carrier 4 must have a minimum reproduction power higher than the theoretical reproduction limit. When the laser beam is irradiated and reproduced, a signal having a pit length exceeding the theoretical reproduction limit can be reproduced.

The support 2 may be in the form of a disk, a card, or a tape. The information recording carriers 1, 4, 6, 8, 9, and 11 may be mounted inside a cartridge. In the case of a disk shape, the diameter is not limited to 120 mm and 45 mm, and the diameter is 4 mm.
It can take various sizes from 0 to 300mm, 51,
64, 80, 86, 95, 130, 200, 260, 3
It may be 00 mm.

The signal recorded on the fine pattern 2A or the recording layer 7 is not limited to a single frequency signal, but may be a modulation signal having various lengths. Specifically, the so-called (d, k)
All kinds of modulated signals called codes can be handled. Either a fixed length code or a variable length code can be used, and both mark edge recording and mark position recording are effective.

In particular, mark edge recording is a kind of fixed length code (2.10) RLL modulation (for example, 8
/ 15 modulation, 8/16 modulation, and 8/17 modulation), mark edge recording and recording, and variable length codes (2.7) modulation and (1.7) modulation are preferably used. In any case, the information record carrier 1, 4, 6, 8, 9, 11 according to the present invention
Of the signals of various lengths, at least the shortest pit length (or shortest mark length) has a length equal to or less than the theoretical reproduction limit.

Next, an information record carrier reproducing apparatus according to the present invention will be described with reference to FIG. An information record carrier reproducing device 12 of the present invention outputs a pickup 13 for reading a record signal recorded on the information record carrier 1, demodulates the record signal, performs error correction as necessary, and outputs a data stream signal. A demodulator 14, an interface 15 for outputting this data stream to the outside, and a pickup 1
3, a power driver 16 for supplying reproduction power to the information recording carrier 1 via the information recording medium 3, a turntable 17 on which the information recording carrier 1 is mounted and rotatable, a motor 18 for rotating the turntable 17, a pickup 13, The power driver 16 includes a servo 19 that performs feedback control of the motor 18, and the demodulator 14, the interface 15, and a controller 20 that controls the servo 19.

The information recording carrier 1 is a disk having a hole H at the center. A protrusion is formed at the center of the turntable 17, and the hole H of the information recording carrier is fitted to the protrusion.

The pickup 13 has a wavelength of about 650, for example.
It comprises at least a light source that emits light at a single wavelength of nm, an objective lens having a numerical aperture of NA 0.6, and a photodetector (photodetector) that receives light reflected from the information recording carrier 1. The power driver 16 is used for a conventional information record carrier reproducing apparatus.
A reproduction power of W or more can be given, and the setting of the reproduction power is performed based on the control of the controller 20.

More specifically, the reproduction power is stored in the controller 20 in advance, and the reproduction power is read out and supplied to the power driver 16. Alternatively, the reproduction power is experimentally recorded at various powers in a predetermined area of the information recording medium 1, and an optimum reproduction power is repeatedly obtained until the reproduction signal output reaches a predetermined value. The read power setting may be read out and supplied to the power driver 16. The output side of the interface 15 may be connected to an external output terminal (not shown), or may be directly connected to an image display device, an audio device, or a printing device (not shown).

Next, the operation of the information record carrier reproducing apparatus of the present invention will be described. The reproducing power stored in the controller 20 in advance is supplied to the pickup 13 via the power driver 16, and a convergent light beam L is incident on the information recording carrier 1 from a light source in the pickup 13 and then reflected there. The recording signal of the information recording carrier 1 is received by the photodetector and output to the demodulator 14.

At this time, under the control of the controller 20,
A servo 19 generates a focus error signal, a tracking error signal, and a rotation servo signal based on the reflected light of the information recording medium 1. The focus error signal and the tracking error signal are generated by the pickup 13, and the rotation servo signal is generated by the motor 18. Then, the pickup 13 follows the information recording carrier 1 and the rotation of the motor 18 is controlled.

The power setting output from the power driver 16 is 0.8 mW or more, preferably 20 dB or more in the case of the information recording carrier 1 in which a microscopic discontinuous film made of aluminum is formed. (For example, 1.5 mW). In the case of an information recording carrier using molybdenum as a raw material, the output is 0.5 mW or more, and desirably, a reproduced signal output (for example, 2 mW) of 20 dB or more is obtained.

Under the control of the controller 20, the demodulator 14 demodulates the recording signal, performs error correction as necessary, and outputs the obtained data stream to the interface 15. Further, it outputs a signal demodulated under the control of the controller 20 to the outside.

As described above, a signal having a pit length exceeding the theoretical reproduction limit can be reproduced only by providing the power driver 16 capable of obtaining a reproduction signal output of 20 dB or more capable of reading a pattern exceeding the theoretical reproduction limit. An inexpensive information record carrier reproducing apparatus can be obtained.

Although the holes H of the information recording carrier 1 are fitted to the projections of the turntable 17, they may be fixedly bonded and integrated, or may be a semi-fixed connection that can be freely attached and detached. The information recording carrier 1 has a disk shape, but is not limited to this, and may be a card shape or a tape shape.

Further, the wavelength used for reproduction or recording / reproduction is not limited to 650 nm, but may be 1300 nm, 9
80 nm, 830 nm, 780 nm, 635 nm, 53
2 nm, 515 nm, 458 nm, 442 nm, 430
nm, 413 nm, 405 nm, 400 nm, 370 n
m etc. can also be used. As a light source in the pickup 13, a semiconductor laser, a gas tube laser, a laser beam having passed through a harmonic converter and wavelength-converted, or the like can be used. The numerical aperture NA of the objective lens is set to 0.
4, 0.45, 0.55, 0.65, 0.7, 0.7
It may be 5, 0.8, 0.85, 0.9, or the like, or may be one or more numerical apertures represented by a solid immersion lens.

[0068]

According to the information recording medium of the present invention, it is possible to reproduce a pit length less than the theoretical reproduction limit, and it is possible to obtain an information recording medium having a higher density than a DVD. According to the information record carrier reproducing device of the present invention,
Since it has a power driver that supplies a reproduction output capable of reading a pattern exceeding the theoretical reproduction limit formed on the information recording carrier to the light source, it is possible to reproduce a signal having a pit length exceeding the theoretical reproduction limit. And the cost of the information record carrier reproducing apparatus is reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an information recording carrier according to an embodiment of the present invention.

FIG. 2 is a plan view showing a morphology of a microscopic discontinuous film formed on a substrate surface.

FIG. 3 is a cross-sectional view showing the vicinity of a microscopic discontinuous film in the information recording carrier according to the embodiment of the present invention.

FIG. 4 shows a first example of the information recording medium according to the embodiment of the present invention.
It is sectional drawing which shows a modification.

FIG. 5 shows a second example of the information record carrier according to the embodiment of the present invention.
It is sectional drawing which shows a modification.

FIG. 6 shows a third example of the information record carrier according to the embodiment of the present invention.
It is sectional drawing which shows a modification.

FIG. 7 shows a fourth example of the information recording carrier according to the embodiment of the present invention.
It is sectional drawing which shows a modification.

FIG. 8 shows a fifth example of the information recording carrier according to the embodiment of the present invention.
It is sectional drawing which shows a modification.

FIG. 9 is a block diagram showing an information record carrier reproducing apparatus for reproducing the information record carrier of the present invention.

FIG. 10 is a sectional view showing a conventional information recording carrier used for a read-only DVD.

[Explanation of symbols]

1, 4, 6, 8, 9, 11 ... information recording carrier, 2 ... support, 2A ... fine pattern, 3 ... microscopic discontinuous film, 3A
... isolated material particles, 5 ... resin layer, 7 ... recording layer, 10 ... dummy support, 12 ... information recording carrier reproducing device, 13 ... pickup, 14 ... demodulator, 15 ... interface, 16
... power driver, 17 ... turntable, 18 ... motor, 19 ... servo, 20 ... controller

Claims (7)

[Claims] An information recording carrier comprising: a support; a fine pattern formed on the support; and a microscopic discontinuous film laminated on the fine pattern. 2. An information recording carrier comprising at least a support, a microscopic discontinuous film laminated on the support, and a recording layer. 3. The information recording carrier according to claim 2, wherein said recording layer is made of at least one of a highly reflective material, a dye material, a phase change material, and a magneto-optical material. 4. The microscopic discontinuous film is composed of isolated material particles separated from each other, and the planar size of the isolated material particles is in the range of 0.001 to 0.1 μm. 4. The information recording carrier according to claim 1, wherein the difference between the height of the uppermost surface and the height of the gap between the isolated material particles is in the range of 0.1 to 20 nm. 5. The information recording carrier according to claim 2, wherein a fine pattern is formed between the support and the microscopic discontinuous film. 6. The information recording carrier according to claim 5, wherein a plane size of the isolated material particle is smaller than a minimum dimension of the fine pattern. 7. An information recording apparatus comprising: a pickup having a light source for reading a recording signal of an information recording carrier; a demodulator for demodulating the recording signal and outputting a data stream signal; and an interface for outputting the data stream signal to the outside. An information recording carrier reproducing apparatus, comprising: a power driver for supplying a reproduction output to the light source, the reproduction output being capable of reading a pattern exceeding a theoretical reproduction limit formed on the information recording medium.