WO2008026426A1

WO2008026426A1 - Optical information recording medium

Info

Publication number: WO2008026426A1
Application number: PCT/JP2007/065356
Authority: WO
Inventors: Hirohisa Yamada; Masaki Yamamoto; Yasuhiro Harada; Go Mori; Hideharu Tajima; Nobuyuki Takamori
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2006-08-28
Filing date: 2007-08-06
Publication date: 2008-03-06
Also published as: JP4597240B2; JPWO2008026426A1

Abstract

An optical information recording medium (1) includes a thin film portion (20) on a substrate (30). The thin film portion (20) has a reproduction layer for changing an optical multiplex interference state when a refractive index n and an attenuation coefficient k are changed by increase of the temperature and a light absorbing layer (22) which absorbs a part of the incident reproduced light and converts the light into heat so as to increase the temperature of the reproduction layer (21). The reproduction layer (21) and the light absorbing layer (22) are arranged in this order from the reproduced light incident side. When the wavelength of the adjacent minimal value and the maximal value in the wavelength distribution of the refractive index of the thin film portion (20) at the room temperature are λmin and λmax and the wavelength of the reproduced light is λr, the reproduction layer (21) satisfies the relationship: λmin < λr < λmax. This realizes an optical information recording medium where information is recorded by the random pattern method including a recording mark not greater than the optical diffraction limit and capable of effectively performing stable ultra-resolution reproduction and improving the recording density.

Description

Specification

Optical information recording medium

Technical field

[0001] The present invention relates to an optical information recording medium capable of recording and reproducing information or only reproducing using light. In particular, the present invention relates to an optical information recording medium using a super-resolution medium technology capable of reproducing a recording mark having an optical resolution or less determined by a diffraction-limited light spot diameter.

Background art

In recent years, with the advancement of advanced information technology, information communication, and multimedia technology, demands for higher density and larger capacity of optical information recording media have increased!

[0003] The upper limit of the recording density of an optical information recording medium is mainly limited by the spot diameter of a light beam for recording or reproducing information. This is because as the recording mark diameter of an optical information recording medium is reduced and the recording density is increased, a plurality of marks are included in the spot area, and each mark cannot be detected! / It is.

[0004] By the way, the spot diameter of the light beam is approximately expressed as λ / ΝΑ where λ is the wavelength of the light source and 開口 is the numerical aperture of the object lens for forming the light spot. Therefore, the optical information recording medium has been improved in recording density by shortening the wavelength λ of the light source and increasing the numerical aperture of the objective lens to reduce the spot diameter of the light beam.

However, the wavelength λ of the light source is considered to be limited by the wavelength in the ultraviolet region due to the absorption of the optical element and the limitation of the sensitivity characteristics of the detector. Further, the improvement of the numerical aperture of the objective lens is almost limited by the allowable amount of tilt of the optical information recording medium. Therefore, there is a limit to improving the recording density by reducing the spot diameter of the light beam.

[0006] Therefore, an optical information recording medium using super-resolution technology, which is a technology capable of reproducing a mark having a length less than the diffraction limit of the reproduction optical system (hereinafter referred to as the light diffraction limit or less), has been developed. I have Hereinafter, an optical information recording medium using this technique is called a super-resolution optical information recording medium, and reproducing a recording pit having a mark length less than the optical diffraction limit using this technique is called super-resolution reproduction. The optical diffraction limit value is theoretically known to be λ / (2 · 2 · ΝΑ) when the wavelength of the reproduction light is obtained and the numerical aperture of the objective lens is ΝΑ. In practice, this The optical diffraction limit value includes a certain width.

[0007] As a technique that enables super-resolution reproduction exceeding this limit, there is a super-resolution technique as shown in Patent Documents;

[0008] Specifically, in Patent Document 1, the reflectance of the thin film portion changes according to the incident light intensity, and the wavelength distribution of the reflectance of the thin film portion at room temperature is the wavelength of the incident light for reproduction. By setting the composition and film thickness of the optical multi-interference film so that it takes a minimum value within the range of ± 80 nm, the effective spot diameter of the light beam is reduced and super-resolution reproduction is possible. An optical information recording medium is disclosed.

[0009] Further, Patent Document 2 discloses an optical information recording medium having a temperature sensitive layer in which the optical characteristics of a light beam change as the temperature rises due to light beam irradiation. This temperature-sensitive layer has a relationship of r 100 <a <λ r when the optical absorption edge wavelength of the temperature-sensitive layer is λ a (nm) and the wavelength of the light beam is λ r (nm). An optical information recording medium is disclosed in which the material of the temperature sensitive layer is selected and / or the film thickness is set, so that the effective spot diameter of the light beam is reduced and super-resolution reproduction is possible. .

[0010] Further, in Patent Document 3, a detailed reproduction principle is unknown. Light that enables super-resolution reproduction by providing a functional layer made of a single metal, semiconductor, or the like on an information recording surface having unevenness. An information recording medium is disclosed.

[0011] In addition, in the optical information recording media described in Patent Documents !! to 3, a system is commonly employed in which marks having the same shape below the optical diffraction limit are arranged in a signal reproducing direction. These optical information recording media reproduce single-frequency repetitive phase pits (mark-space ratio 1: 1, hereinafter referred to as monotone pattern method), and C / N (Carrier to Noise ratio, (Carrier-to-noise ratio). This evaluation describes that the recording density can be improved and super-resolution reproduction can be performed.

However, in general, in the reproduction beam scanning direction, the minimum length pre-pit that is the shortest mark length and several types of pre-pits based on the length are defined by the standards, and these lengths are different. A system in which prepits are arranged in order in the direction of signal reproduction in accordance with the rules stipulated by the standard is used (hereinafter referred to as random pattern system). [0013] Thus, compared to the case where information is recorded using a mark having the same length below the optical diffraction limit, a random pattern method using a mark having a length below the optical diffraction limit as a reference for the minimum mark is used. To record information at a higher density.

[0014] There are many practical examples of this random pattern method. For example, in the case of CD, EFM (8-14) modulation (Eight to Fourteen Modulation) is adopted. Also, in the case of DVD, Blu-RayDisc (BD; registered trademark) and HD-DVD, the modulation method is different from that of CD, EFMPlus (8-16) modulation method for DVD, 1-7PP modulation method for HD, HD — DVD uses ETM (8-12) modulation method. In other words, in many optical information recording media, a random pattern method capable of improving the recording density is adopted.

As described above, in the case of a random pattern method which is a general recording method, jitter is important as an evaluation index. Hereinafter, jitter will be described.

When reproducing an optical information recording medium, when a reproduction light beam is irradiated onto a mark on which information is recorded, a signal is generated by detecting a change in the amount of reflected light (reflection intensity). The Actually, in this process, a signal conversion point position error, that is, jitter occurs. Jitter is caused by a variety of factors, but may be caused by noise (laser noise, crosstalk due to reflected diffracted light from adjacent tracks, noise due to media defects, etc.). When the jitter becomes large, a read error occurs in the reproduction system, and stable reproduction becomes difficult. Therefore, jitter reduction is indispensable in order to enable stable super-resolution reproduction and to increase the density of super-resolution optical information storage media.

By the way, when reproducing an optical information recording medium having only a mark length larger than the optical diffraction limit, the jitter is reduced as the C / N is improved. Therefore, since there is a correlation between C / N and jitter, it is only necessary to evaluate only C / N and improve the C / N.

[0018] However, the power to be described later in detail. We have included a random pattern including a mark having a length less than or equal to the optical diffraction limit (a plurality of lengths of convexes and / or concaves are arranged according to recorded information, and light Information is recorded in a way that includes convex and / or concave lengths below the diffraction limit) The present inventors have found that the above-described correlation does not always hold when reproducing the recorded optical information recording medium. In other words, in the case of an optical information recording medium in which information is recorded by a random pattern method including a recording mark having a length less than or equal to the optical diffraction limit, improvement of C / N alone does not necessarily lead to reduction of jitter. I understood.

That is, it is composed of a substrate on which information is recorded in a monotone pattern system having a mark length equal to or less than the optical diffraction limit and having the same shape of the marks arranged at equal intervals, and super-resolution reproduction is possible. Good C / N is obtained in an optical information recording medium. This means that the reproduction characteristics of an optical information recording medium in which information is recorded only by the same mark below the optical diffraction limit and super-resolution reproduction is possible. It shows that it is guaranteed. However, information that is recorded in a random pattern system that includes marks with a length less than or equal to the optical diffraction limit and that can be recorded with higher density! /, That enables super-resolution reproduction There is no guarantee for the playback characteristics of the recorded information medium.

[0020] Therefore, in an optical information recording medium capable of super-resolution reproduction by a random pattern method, the correlation between C / N and jitter does not always hold, so C / N is improved. At the same time, it is necessary to consider reducing jitter. In other words, the reduction of jitter is important for the realization of a super-resolution medium compatible with a higher pattern density random pattern method.

[0021] Further, in general, an optical information recording medium using super-resolution technology often has insufficient reproduction durability, and the power consumption of a drive device with high power of a light beam irradiated during reproduction is high. There is also the problem of becoming higher.

Patent Document 1: Japanese Patent Publication “JP 2005-18964 Publication (Publication Date: January 20, 2005)”

Patent Document 2: Japanese Published Patent Publication “Japanese Patent Laid-Open No. 2006-73169 (Publication Date: March 16, 2006)”

Patent Document 3: Japanese Patent Publication “Japanese Unexamined Patent Publication No. 2001-250274 (Publication Date: September 14, 2001)”

Disclosure of the invention

[0022] The present invention has been made in view of the above problems, and its purpose is to achieve stable supersolution. Realizing an optical information recording medium on which information is recorded by a random pattern method including marks having a length less than or equal to the optical diffraction limit, which enables efficient image reproduction and further improvement in recording density There is.

In the first optical information recording medium according to the present invention, in order to solve the above problems, the reflectance changes from the incident side of the reproduction light based on the change in the state of the light transmitting layer and the optical multiple interference. An optical information recording medium in which a thin film portion and a substrate on which information is recorded by a random pattern method consisting of convex and / or concave corresponding to recording information are sequentially laminated, wherein the thin film portion is for reproducing light. As the temperature rises in order from the incident side, the optical constant at the wavelength of the reproduction light, which changes the refractive index and extinction coefficient, changes the optical multiple interference state, and the incident layer. A light absorption layer that raises the temperature of the reproduction layer by absorbing a portion of the reproduced light that is converted into heat, and has a wavelength distribution of the reflectance at room temperature of the thin film portion. O! /, The local minimum and local maximum will be next to each other Length, respectively, and min Oyobie max, when the e r the wavelength of the reproduction light, the relationship of λ min <λ r <λ max is satisfied.

[0024] In a random pattern type optical information recording medium including a recording mark having a length less than or equal to the optical diffraction limit manufactured by using a conventional super-resolution technique, even when C / N is improved. Jitter is not always reduced. Therefore, reducing jitter is important for stable super-resolution reproduction.

[0025] According to the above configuration, the translucent layer, the thin film portion, and the substrate are laminated in this order from the side on which the reproduction light is incident, and adjacent to each other in the reflectance wavelength distribution of the thin film portion at room temperature. The thin film portion is formed so that the relationship of min <λ τ <λ max is established, where the minimum and maximum wavelengths to be matched are min and max, respectively, and the wavelength of the reproduction light is r. Has been.

In this case, the refractive index at the high temperature of the reproducing layer constituting the thin film portion increases as compared with that at the room temperature. Along with this, the wavelength distribution of the reflectance of the thin film portion at high temperature shifts to the longer wavelength side in the same manner as that at room temperature. The wavelength distribution of reflectance at room temperature of the thin film part is! /, Where the minimum and maximum adjacent wavelengths are min and max, respectively. So of the playback light The reflectivity of the thin film portion at the wavelength r decreases at higher temperatures (see FIG. 1). Furthermore, as the extinction coefficient of the reproducing layer increases, the transmittance of the reproducing layer decreases. As a result, the extinction coefficient of the reproducing layer works to reduce the reflectivity of the thin film portion. In this way, each change in refractive index and extinction coefficient enhances the decrease in reflectivity of the thin film portion.

[0027] Therefore, in the high temperature region of the light spot of the reproduction light, both the refractive index and the extinction coefficient work to lower the reflectivity of the thin film portion, and the change in reflectivity is enhanced, thereby effectively reducing jitter. It will be possible to achieve this. That is, read errors occur in the reproduction system, and stable super-resolution reproduction can be performed efficiently, and the reproduction sensitivity of the optical information recording medium can be improved.

[0028] The wavelength distribution of the reflectance of the thin film portion depends on the film thickness of the thin film portion. For this reason, it is possible to form the thin film portion by setting the film thickness of the reproducing layer so that the relationship of max≤λτ≤min is established in the wavelength distribution of the reflectance of the thin film portion at room temperature. Noh. In this case, the refractive index n at a high temperature of the reproducing layer constituting the thin film portion increases as compared with that at room temperature. Along with this, the wavelength distribution of reflectance at high temperatures in the thin film part shifts to the longer wavelength side compared to that at room temperature (see Fig. 5). That is, since λ max approaches the wavelength λ r of the reproduction light, the reflectance of the thin film portion at the wavelength λ r of the reproduction light increases at a high temperature. However, at this time, the extinction coefficient k of the reproducing layer increases, and thus the transmittance of the reproducing layer decreases. As a result, the extinction coefficient k of the reproducing layer works to reduce the reflectivity of the thin film portion. Thus, changes in the refractive index n and the extinction coefficient k do not enhance the reflectance change of the thin film portion. Therefore, it is preferable that the thin film portion has the structure according to the present invention!

[0029] Further, since the wavelength distribution of the reflectance of the thin film portion depends on the film thickness of the thin film portion, the reflectance control of the optical information recording medium can be easily performed, and the production cost of the optical information recording medium is reduced. The power to make it becomes S Kanakura.

[0030] Further, according to the above configuration, in the thin film portion, the reproduction layer that changes the state of optical multiple interference due to a temperature rise and the light absorption layer that raises the temperature of the reproduction layer are separately formed. Therefore, it is possible to improve the reproduction durability. [0031] In order to solve the above problems, the second optical information recording medium according to the present invention provides information from the incident side of the reproduction light by a random pattern method consisting of convex and / or concave corresponding to the recorded information. Is an optical information recording medium in which a thin film portion whose reflectivity changes based on a change in the state of optical multiple interference is laminated, and the thin film portion is from the incident side of the reproduction light. In turn, as the temperature rises, the optical constant at the wavelength of the reproduction light, which changes the refractive index and extinction coefficient, changes the state of optical multiple interference, and the incident reproduction A light absorption layer that raises the temperature of the regeneration layer by absorbing part of the light and converting it into heat, and the adjacent local minimum value in the wavelength distribution of the reflectance of the thin film portion at room temperature And the maximum wavelength And min Oyo Bie max, when the e r the wavelength of the reproduction light, to establish the relationship min <λ τ <λ max

[0032] According to the above configuration, the substrate and the thin film portion are sequentially laminated from the side on which the reproduction light is incident, and the adjacent local minimum value and local maximum value in the wavelength distribution of the reflectance of the thin film portion at room temperature. The thin film portion is formed so that the relationship of min <λ τ <λ max is established, where min and e max are the wavelengths to be obtained, and r is the wavelength of the reproduction light.

In this case, the refractive index at the high temperature of the reproducing layer constituting the thin film portion increases as compared with that at the room temperature. Along with this, the wavelength distribution of the reflectance of the thin film portion at high temperature shifts to the longer wavelength side in the same manner as that at room temperature. The wavelength distribution of reflectance at room temperature of the thin film part is! /, Where the minimum and maximum adjacent wavelengths are min and max, respectively. Therefore, the reflectivity of the thin film portion at the wavelength r of the reproduction light decreases at a high temperature (see Fig. 1). Furthermore, as the extinction coefficient of the reproducing layer increases, the transmittance of the reproducing layer decreases. As a result, the extinction coefficient of the reproducing layer works to reduce the reflectivity of the thin film portion. In this way, each change in refractive index and extinction coefficient enhances the decrease in reflectivity of the thin film portion.

[0034] Therefore, in the high temperature region of the light spot of the reproduction light, both the refractive index and the extinction coefficient work to lower the reflectivity of the thin film portion, and the change in reflectivity is enhanced, thereby effectively reducing jitter. It will be possible to achieve this. That is, reading in the playback system However, an error occurs, so that stable super-resolution reproduction can be performed efficiently, and the reproduction sensitivity of the optical information recording medium can be improved.

[0035] Further, since the wavelength distribution of the reflectance of the thin film portion depends on the film thickness of the thin film portion, the reflectance control of the optical information recording medium can be easily performed, and the production cost of the optical information recording medium is reduced. The power to make it becomes S Kanakura.

Furthermore, according to the above configuration, in the thin film portion, the reproducing layer that changes the state of optical multiple interference due to a temperature rise and the light absorption layer that raises the temperature of the reproducing layer are separately formed. Therefore, it is possible to improve the reproduction durability.

[0037] In order to solve the above problems, the third optical information recording medium according to the present invention has a translucent layer, a metal oxide, or a mixture containing the metal oxide as main components from the incident side of the reproduction light. The information is recorded by a metal oxide layer made of Si, Ge, or a thin film layer made of a mixture mainly composed of Si, Ge, or which force, and a random pattern method of convex and / or concave according to the recorded information. The optical information recording medium in which the substrate is laminated in order, and the wavelength distribution of the reflectance at the room temperature of the thin film portion composed of the metal oxide layer and the thin film layer, the wavelength having the adjacent minimum value and the maximum value is determined. When min and e max are set, and the wavelength of the reproduction light is r, the relationship of min λ τ <λ max is established.

[0038] According to the above configuration, the optical information recording medium has a metal oxide layer mainly made of a metal oxide and a thin film layer made of a mixture mainly composed of Si, Ge, or which force. And the thin film part is comprised by the said metal oxide layer and thin film layer.

[0039] In the wavelength distribution of the reflectance of the thin film portion at room temperature, when the adjacent local minimum and local maximum wavelengths are min and max, respectively, and the reproduction light wavelength is r, The thin film portion is formed so that the relationship of l min <λΐ <λ max is established.

In this case, the refractive index at a high temperature of the reproducing layer constituting the thin film portion increases as compared with that at a room temperature. Along with this, the wavelength distribution of the reflectance of the thin film portion at high temperature shifts to the longer wavelength side in the same manner as that at room temperature. The wavelength distribution of reflectance at room temperature of the thin film part is! /, Where the minimum and maximum adjacent wavelengths are min and max, respectively. Therefore, the reflectivity of the thin film portion at the wavelength r of the reproduction light decreases at a high temperature (see Fig. 1). further, As the extinction coefficient of the reproducing layer increases, the transmittance of the reproducing layer decreases. As a result, the extinction coefficient of the reproducing layer works to reduce the reflectivity of the thin film portion. In this way, each change in refractive index and extinction coefficient enhances the decrease in reflectivity of the thin film portion.

Yes

[0041] Therefore, in the high temperature region of the light spot of the reproduction light, both the refractive index and the extinction coefficient work to lower the reflectivity of the thin film portion, and the change in reflectivity is enhanced, so that the jitter is efficiently reduced. It will be possible to achieve this. That is, read errors occur in the reproduction system, and stable super-resolution reproduction can be performed efficiently, and the reproduction sensitivity of the optical information recording medium can be improved.

[0042] Further, since the wavelength distribution of the reflectance of the thin film portion depends on the film thickness of the thin film portion, the reflectance control of the optical information recording medium can be easily performed, and the production cost of the optical information recording medium is reduced. The power to make it becomes S Kanakura.

[0043] Further, according to the above configuration, in the thin film portion, the reproduction layer that changes the state of optical multiple interference due to the temperature rise and the light absorption layer that raises the temperature of the reproduction layer are separately formed. Therefore, it is possible to improve the reproduction durability.

In the fourth optical information recording medium according to the present invention, in order to solve the above-mentioned problem, information is recorded from the incident side of the reproduction light by a random pattern method composed of convex and / or concave according to the recording information. And a metal oxide, or a metal oxide layer composed of the metal oxide as a main component, and a thin film layer composed of Si or Ge, or a mixture based on either of them. In the optical information recording medium laminated in order, in the wavelength distribution of the reflectance at room temperature of the thin film portion composed of the metal oxide layer and the thin film layer, adjacent minimum and maximum wavelengths are set to min and When max is set and r is the wavelength of the reproduction light, the relationship min <λ τ <λ max is established.

[0045] According to the above configuration, the optical information recording medium has a metal oxide layer mainly made of a metal oxide and a thin film layer made of a mixture mainly composed of Si, Ge, or which force. And the thin film part is comprised by the said metal oxide layer and thin film layer.

[0046] Further, in the wavelength distribution of the reflectance of the thin film portion at room temperature, the minimum and maximum wavelengths adjacent to each other are min and max, respectively, and the wavelength of the reproduction light is r. Then, the thin film portion is formed so that the relationship of l min <λ τ <λ max is established.

[[00004488]] Therefore, the refractive index and extinction of the regenerated raw light in the high and high temperature region of the light spot. Both coefficient factors work to lower the anti-reflective emissivity of the thin film part, and the change in anti-reflective emissivity increases and increases the strength. As a result, it can be considered that it will become possible to achieve a low reduction and reduction of the jitter in an efficient manner. . Susuna, that is, reading and reading in a regenerative reproduction system, and erroneous errors occur. This is an efficient and efficient way to perform the re-playing of the resolution and improves the sensitivity of the re-playing of the optical information recording / recording medium. This is what makes you uplifted. .

[[00004499]] Also, the wave length distribution of the anti-reflection emissivity of the thin film portion depends on the film thickness of the thin film portion. Therefore, it is possible to easily and easily control the anti-reflective emissivity control of the optical information recording / recording medium body. This will reduce the production cost of the information recording / recording medium, and this will be the power SS Kanakura. .

[[00005500]] Furthermore, according to the above configuration, according to the above configuration, the thin film portion is covered with the temperature and temperature. A regenerated biolayer that changes the state of the photo-optics multi-multilayer interference, and the temperature temperature of the regenerated biolayer is increased and raised. The light-absorbing and absorbing layer to be formed is separated and formed into a separated shape, which improves the durability of the regenerated raw material. And become possible. .

[[00005511]] Other objectives, features, and superior points of the present invention are described below. It will take ten minutes enough. . In addition, the advantages of the present invention are clearly and clearly made clear by the following explanation with reference to the attached drawings. Let ’s do it. .

Simple and simple explanation on the drawing

[[00005522]] [[Fig. 11]] This shows one embodiment of the present invention, and is a recording medium for optical information recording / recording medium. Measurement of anti-reflectance emissivity of constant wave wavelength

FIG. 2 is a schematic diagram of an optical system of a recording / reproducing apparatus capable of recording / reproducing information using the optical information recording medium of the present invention.

FIG. 3, showing Embodiment 1 of the present invention, is a sectional view showing a schematic configuration of an optical information recording medium.

4 is a diagram showing a schematic configuration of prepits provided on a substrate on which the optical information recording medium shown in FIG. 3 is formed.

[FIG. 5U is a diagram showing a spectral spectrum with respect to the measurement wavelength of the reflectance of the optical information recording medium in the case of a relationship of max≤λτ≤λmin.

FIG. 6 shows Example 1 of the optical information recording medium shown in FIG. 3, wherein the thickness of the reproducing layer is

It is sectional drawing which shows schematic structure of the optical information recording medium set to 11 lnm.

FIG. 7 shows Comparative Example 1 of the optical information recording medium shown in FIG.

It is sectional drawing which shows schematic structure of the optical information recording medium set to 144 nm.

FIG. 8 is a cross-sectional view showing a schematic configuration of an optical information recording medium that does not use the super-resolution medium technology, showing Comparative Example 2 of the optical information recording medium shown in FIG.

FIG. 9 is a cross-sectional view showing a schematic configuration of an optical information recording medium shown in FIG. 6, in which Comparative Example 3 of the optical information recording medium shown in FIG.

FIG. 10 is a diagram showing a change in jitter with respect to reproducing optical laser power in the optical information recording media shown in FIGS. 6 to 9, respectively.

FIG. 11 is a diagram showing a change in jitter with respect to the thickness of the light absorption layer of the optical information recording medium shown in FIG.

FIG. 12, showing Embodiment 2 of the present invention, is a cross-sectional view showing a schematic configuration of an optical information recording medium when reproducing light is incident from the substrate side.

Explanation of symbols

1, 2, 6 Optical information recording media

10 Translucent layer

20 Thin film part

21 Playback layer

22 Light absorption layer 30 substrates

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1]

One embodiment of the present invention is described below with reference to FIGS.

First, the main configuration of a recording / reproducing apparatus capable of recording / reproducing information with respect to the optical information recording medium of the present invention will be described.

The recording / reproducing apparatus includes a laser light source, condensing optical means, relative motion means, photoelectric conversion means, servo means, address information detection means, and a reproduction signal demodulation circuit.

As the laser light source, for example, a semiconductor laser that emits light with a wavelength of 406 nm can be used.

[0058] The condensing optical means condenses the laser light generated by the laser device force in the form of a beam on an optical information recording medium, and includes optical components such as a condensing lens and a beam splitter.

[0059] The relative motion means is for moving the condensing optical means and the optical information recording medium relative to each other, and is composed of a linear actuator such as a swing arm. The movement includes at least one of a movement in which the optical information recording medium rotates or translates, and a movement in which the condensing lens included in the condensing optical means moves in a direction perpendicular to the optical axis.

[0060] The photoelectric conversion means converts the level of reflected light from the optical information recording medium into an electric signal, and the servo means performs autofocus and tracking of the laser light.

[0061] The address information detecting means detects address information from an electrical signal obtained by reproducing an address information mark provided on the optical information recording medium. The reproduction signal demodulating circuit The recorded information is reproduced from the reflected light of the recording medium.

Of these components, the laser light source, the condensing optical means, the photoelectric conversion means, and the servo means are housed in an optical head that performs relative motion with the optical information recording medium by the relative motion means. . It is also possible to place the laser light source and the photoelectric conversion means in a separate case from the condensing optical means. [0063] In addition, it is preferable that the recording / reproducing apparatus further includes means for adjusting the angle formed between the focused laser beam and the optical information recording medium. In addition, the deterioration of the light spot due to the occurrence of aberration can be prevented.

FIG. 2 shows a configuration diagram of a general optical system when the optical information recording medium mounted on such a recording / reproducing apparatus as an optical head is a disc-shaped optical disk. The optical system includes a semiconductor laser 61, a collimating lens 62, a beam shaping prism 63, a beam splitter 64, an objective lens 65, and a detection optical system 67.

Laser light from the semiconductor laser 61 as a light source is converted into substantially parallel light by the collimator lens 62, and the light intensity distribution is shaped into a substantially circular shape by the beam shaping prism 63. The substantially circular parallel light passes through the beam splitter 64 and is then focused on the optical information recording medium 66 by the objective lens 65. This reflected light is branched by the beam splitter 64 and guided to the detection optical system 67.

The spindle motor 68 rotates the optical information recording medium 66 to scan the optical spot on the optical information recording medium 66. The detection optical system 67 discriminates signals from changes in the polarization direction of reflected light and changes in reflected light intensity, and at the same time reads the recording marks recorded on the optical information recording medium 66 and simultaneously records the optical information of the light spot. By detecting a defocus signal and a track position shift signal with respect to the medium 66 and feeding back to the drive system of the objective lens 65, the position shift of the light spot is corrected. For example, the numerical aperture (NA) of the objective lens is set to 0.85.

In such an optical information recording / reproducing apparatus, the optical information recording medium 66 and the optical information recording medium 66 according to the present invention adopting the super-resolution medium technology as the optical information recording medium 66 and the super-resolution medium technology. It is desirable to be able to record / reproduce both the optical disc and the ordinary optical information recording medium. Therefore, in the optical information recording / reproducing apparatus, the gain of the detector, the reproduction light intensity, the recording light intensity, the recording waveform, in the case of the optical information recording medium according to the present invention and in the case of the normal optical information recording medium, The optical information recording medium is configured to be able to switch the number of rotations. However, since these are in an electrically controllable range, it is not necessary to make significant changes to the optical system as compared with an apparatus that records and reproduces only ordinary media.

Next, an optical information recording medium using the super-resolution medium technique according to the present invention will be described. . FIG. 3 is a cross-sectional view showing a schematic configuration of the optical information recording medium 1 according to the present embodiment.

As shown in FIG. 3, the optical information recording medium 1 includes a light-transmitting layer 10, a thin film portion 20, and a substrate 30, and is formed in this order from the reproduction light incident surface.

[0070] The light transmissive layer 10 may be made of a material that can sufficiently transmit the reproduction light. For example, the light transmissive layer 10 is formed of polycarbonate film, ultraviolet curable resin, or the like. As a result, it is possible to prevent the thin film portion 20 from being broken by an external factor.

As shown in FIG. 4, the substrate 30 is formed with concavity and convexity prepits (pits) 31 corresponding to recording information in a concentric or spiral shape. The optical characteristics of the material constituting the substrate 30 are not particularly limited and may be transparent or opaque. Examples of the material constituting the substrate 30 include glass, polycarbonate, amorphous polyolefin, thermoplastic polyimide, thermoplastic transparent resins such as PET, PEN, and PES, thermosetting polyimide, and ultraviolet curable acrylic resin. Examples thereof include curable transparent resins, metals, and the like, and combinations thereof.

The thin film portion 20 includes a reproduction layer 21 and a light absorption layer 22, and is formed in this order from the reproduction light incident surface. In addition to 1S formed by the reproduction layer 21 and the light absorption layer 22, the thin film portion 20 includes, for example, a reflection that reflects reproduction light between the light absorption layer 22 and the substrate 30. A layer may be provided.

[0073] When the temperature rises, the reproduction layer 21 changes the refractive index n and the extinction coefficient k, which are optical constants at the wavelength of the reproduction light, and causes optical multiple interference. The light absorption layer 22 absorbs a part of the reproduction light and converts it into heat, thereby raising the temperature of the reproduction layer 21.

[0074] Specifically, when the reproduction light is incident on the optical information recording medium 1, the light absorption layer 22 absorbs a part of the reproduction light and converts it into heat. When this heat is supplied to the reproduction layer 21, a high temperature region and a low temperature region are generated in the light spot region of the reproduction light on the reproduction layer 21. Corresponding to this temperature distribution, in the high temperature region, the refractive index n and the extinction coefficient k, which are the optical constants of the reproducing layer 21, change, respectively, thereby changing the complex refractive index. Along with this, the state of optical multiple interference in the reproduction layer 21 changes, and as a result, the reflectance of the reproduction layer 21 changes.

[0075] Therefore, when the reflectance of a part of the light spot changes according to the incident intensity of the reproduction light, the recording mark that is in the light spot area and is smaller than the light spot is emphasized and read. Ability to do S. As a result, the effective reproduction spot can be reduced, so that super-resolution reproduction is possible and the recording density can be improved.

[0076] In addition, the material constituting the reproduction layer 21 is excellent in durability that the composition or shape hardly changes even when a chemical structural change is repeated due to a temperature change. And metal oxides. Specific examples include zinc oxide, tin oxide, indium oxide, nickel oxide, vanadium oxide, titanium oxide, cerium oxide, strontium titanate, cobalt oxide, and tantalum oxide. Of these, zinc oxide is particularly preferable because it is inexpensive and has a low environmental impact. A mixture containing these as main components may also be used.

Furthermore, the thickness S of the reproducing layer 21 is preferably 80 nm or more and less than 120 nm from experiments and theoretical values. The film thickness of the reproducing layer 21 will be described in detail later.

[0078] Further, as a material constituting the light absorption layer 22, any material that absorbs light to some extent and can effectively raise the temperature of the reproduction layer 21 can be used. Examples include metals, phase change materials, and organic dyes. In particular, organic dyes are expensive, and phase change materials are difficult to manage. Therefore, Si or Ge or a mixture based on Si or Ge is cheaper than semiconductors or metalloids such as Si and Ge. Is preferred.

Furthermore, the light absorption layer 22 is formed on the substrate 30 so that the unevenness of the prepits 31 is reflected. The light absorption layer 22 is usually formed by a magnetron sputtering method. However, the atoms forming the light absorption layer 22 evaporated by sputtering do not necessarily enter the substrate 30 completely perpendicularly. For this reason, if the thickness of the light absorption layer 22 is greater than 500 nm, the unevenness of the prepits 31 may not be accurately reflected. Therefore, the film thickness of the light absorption layer 22 is preferably 500 nm or less. The film thickness of the light absorption layer 22 will be described in detail later.

[0080] As described above, since the thickness of the reproducing layer 21 is set to 80 nm or more and less than 120, the wavelength distribution of the reflectance of the thin film portion 20 at room temperature (30 ° C) is As shown in FIG. 1, when the adjacent local minimum and local maximum values are min and max, respectively, and the wavelength of the reproduction light is r, min <r <max.

In this case, the refractive index n of the reproducing layer 21 forming the thin film portion 20 increases as the temperature increases. . Accordingly, as shown in FIG. 1, the wavelength distribution of the reflectance of the thin film portion 20 at a high temperature (200 ° C.) is shifted to the longer wavelength side as compared with the wavelength distribution at room temperature. For this reason, at the wavelength r of the reproduction light, the reflectance of the thin film portion 20 at a high temperature is lower than the reflectance at a room temperature. Further, since the extinction coefficient k of the reproducing layer 21 increases as the temperature increases, the transmittance of the reproducing layer 21 is reduced accordingly. Therefore, the reflectance of the thin film portion 20 is lowered at the wavelength r of the reproduction light. Therefore, when the wavelength distribution of the reflectance of the thin film portion 20 at room temperature is λ min and λ τ <λ max, the refractive index n and the extinction coefficient k in the high temperature region of the light spot of the reproduction light Both act to enhance the change in the reflectivity of the thin film portion 20.

[0082] Note that the film thickness of the reproducing layer 21 is preferably set to 80 nm or more and less than 120 nm, but it can be set at less than 80 nm or 120 nm or more even at room temperature. The force S can be applied so that the wavelength distribution of the reflectance of the thin film portion 20 satisfies min <λ τ <λ max.

However, when the thickness of the reproducing layer 21 is less than 80 nm, the effect of optical multiple interference cannot be obtained sufficiently, and there is a possibility that stable super-resolution reproduction cannot be performed. Further, when the thickness of the reproducing layer 21 is 120 nm or more, there is a possibility that the minimum value of the reflectance is around 00 nm in the wavelength dependence of the reflectance of the thin film portion 20. At this time, for example, when a Blu-ray optical system is used, the wavelength of the reproduction light and the wavelength that takes the minimum value of the reflectance are close to each other. For this reason, when the optical information recording medium is reproduced, the necessary reflected light cannot be obtained sufficiently, and the focus focus is increased. Furthermore, when the optical information recording medium is reproduced, the heat supplied from the light absorption layer 22 cannot be sufficiently obtained, and there is a possibility that the reproduction sensitivity is lowered.

Therefore, the thickness of the reproducing layer 21 is preferably set to 80 nm or more and less than 120 nm.

On the other hand, FIG. 5 shows the wavelength distribution of the reflectance of the thin film portion 20 at room temperature (30 ° C.) when the thickness of the reproducing layer 21 is 144 nm. As shown in FIG. 5, the relationship between the adjacent minimum value λ min and maximum value λ max of the wavelength distribution and the wavelength λ r of the reproduction light is λ max ≤ λ τ ≤ λ min. Also in this case, the refractive index n of the reproducing layer 21 forming the thin film portion 20 increases as the temperature increases. Accordingly, the wavelength distribution of the reflectance of the thin film portion 20 at a high temperature (200 ° C.) is shifted to the longer wavelength side as compared with the wavelength distribution at room temperature, as shown in FIG. For this reason, at the wavelength r of the reproduction light, the reflectance of the thin film portion 20 at a high temperature is higher than the reflectance at a room temperature. On the other hand, the extinction coefficient k of the reproducing layer 21 increases as the temperature increases, and accordingly, the transmittance of the reproducing layer 21 is decreased. For this reason, the reflectance of the thin film portion 20 is lowered at the wavelength of the reproduction light. Therefore, when the wavelength distribution of the reflectivity of the thin film portion 20 at room temperature is max≤ λ τ≤ λ min, the refractive index n and the extinction coefficient k are It can be seen that the change in the reflectivity of the thin film portion 20 is strengthened.

As described above, when the wavelength distribution of the reflectance of the thin film portion 20 at room temperature is min <λ τ <λ max, the refractive index n and the extinction coefficient k are the reflectance of the thin film portion 20. Jitter can be reduced because it works to increase the rate drop. That is, since the optical information recording medium 1 can efficiently perform stable super-resolution reproduction, the reproduction sensitivity of the optical information recording medium 1 can be improved.

Further, the thin film portion 20 of the optical information recording medium 1 is separately formed into a reproducing layer 21 and a light absorbing layer 22. Thereby, since the role is shared in the thin film portion 20, it is possible to improve the reproduction durability.

Furthermore, the wavelength distribution of the reflectance of the thin film portion 20 at room temperature can be appropriately changed according to the film thickness of the reproducing layer 21. Accordingly, since the reflectance control of the optical information recording medium 1 can be easily performed, the production cost of the optical information recording medium 1 can be reduced.

[0090] Note that the jitter is reduced by setting the film thickness of the reproducing layer 21 so that the wavelength distribution of the reflectance of the thin film portion 20 at room temperature is λ min <λ r <λ max. Hereinafter, the present invention will be described in detail by showing examples.

[0091] (Example)

As shown in FIG. 6, the optical information recording medium 2 is Example 1 of the optical information recording medium 1, and is the most preferable example of the optical information recording medium 1. The optical information recording medium 2 includes a translucent layer 10, A thin film portion 20 and a substrate 30 are provided, and are formed in this order from the reproduction light incident surface.

[0092] The light-transmitting layer 10 includes a polycarbonate film 11 (film thickness: 80 in) and a transparent adhesive layer 12 (film thickness).

: 2 (^ 111) and is formed in this order from the reproduction light incident surface. The thin film portion 20 includes a reproduction layer 21 (thickness: 11 lnm) made of zinc oxide and a light absorption layer 22 (thickness: 50 nm) made of Ge, and is formed in this order from the reproduction light incident surface. The substrate 30 is made of a polyolefin resin.

In the above configuration, the film thickness of the thin film portion 20 of the optical information recording medium 2 in Example 1 is set so that the relationship of l min <λ τ <λ max is satisfied.

Further, as shown in FIG. 7, the optical information recording medium 3 is a comparative example 1 of the optical information recording medium 1, and includes a light-transmitting layer 10, a thin film portion 20, and a substrate 30, and is reproduced. They are formed in this order from the light incident surface.

[0095] The light transmitting layer 10 includes a polycarbonate film 11 (film thickness: 80 in) and a transparent adhesive layer 12 (film thickness).

: 2 (^ 111) and is formed in this order from the reproduction light incident surface. The thin film portion 20 includes a reproduction layer 21 (thickness: 144 nm) made of zinc oxide and a light absorption layer 22 (thickness: 50 nm) made of Ge, and is formed in this order from the reproduction light incident surface. The substrate 30 is made of a polyolefin resin. That is, the thickness of the reproducing layer 21 of the optical information recording medium 3 is set to 120 nm or more, which is thicker than the thickness of the reproducing layer 21 of the optical information recording medium 2. In the above configuration, the film thickness of the thin film portion 20 of the optical information recording medium 3 in Comparative Example 1 is set so as to satisfy the relationship of max ≦ λτ ≦ min.

Here, the optical information recording media 2 and 3 are produced by the following method, for example.

[0097] First, in 5 X 10_ ⁴ (Pa) in a sputtering apparatus which is evacuated to less, on a substrate 30 made of 0. 05mm thick polyolefin-based resin, after placing the Ge 3-inch diameter as a target, sputtering Argon gas is fed into the device and high-frequency power 200W is supplied. As a result, the light absorption layer 22 made of Ge and having a thickness of 50 nm is formed on the substrate 30.

[0098] Next, after arranging zinc oxide as a target in the sputtering apparatus, a mixed gas of argon and oxygen (argon flow rate: oxygen flow rate = 16: 1) is fed and high-frequency power 200W is supplied. As a result, a reproducing layer 21 made of zinc oxide and having a thickness of 11 lnm or 144 nm is formed on the light absorption layer 22, and as a result, the thin film portion 20 is formed on the substrate 30. [0099] Thereafter, the disk having the thin film portion 20 formed on the substrate 30 is taken out into the atmosphere, and the polycarbonate film 11 having a thickness of 80 nm and the transparent adhesive layer 12 having a thickness of 20 nm are used on the thin film portion 20. And paste them together. Thereby, the translucent layer 10 is formed on the thin film portion 20. In this way, optical information recording media 2 and 3 are produced.

Further, as shown in FIG. 8, the optical information recording medium 4 is a comparative example 2 with respect to the optical information recording medium 2, and does not use the super-resolution medium technology! / Show me!

The optical information recording medium 4 includes a light transmitting layer 10, a thin film layered portion 40, and a substrate 30, and is formed in this order from the reproduction light incident surface!

[0102] The light transmissive layer 10 includes a polycarbonate film 11 (film thickness: 80 111) and a transparent adhesive layer 12 (film thickness: 20 ^ m), and is formed in this order from the reproduction light incident surface! /, The The film thickness of the thin film layered portion 40 made of Au is 50 nm. The substrate 30 is made of a polyolefin resin.

Further, as shown in FIG. 9, the optical information recording medium 5 is a comparative example 3 with respect to the optical information recording medium 2, and shows the super-resolution optical information recording medium described in Patent Document 3! / The

[0104] The optical information recording medium 5 includes a light transmitting layer 10, a thin film layered portion 50, and a substrate 30, and is formed in this order from the reproduction light incident surface.

[0105] The light-transmitting layer 10 includes a polycarbonate film 11 (film thickness: 80 111) and a transparent adhesive layer 12 (film thickness).

20 111) and is formed in this order from the reproduction light incident surface. The film thickness of the thin film layered portion 50 made of Ge is 50 nm. The substrate 30 is made of a polyolefin resin.

Further, as shown in FIG. 4, the substrate 30 forming the optical information recording media 2, 3, 4 and 5 has a monotone pattern system having a mark length of 0 · 12 m which is not more than the optical diffraction limit. Is used, and single frequency repetitive phase pits (mark'space ratio 1: 1) are recorded.

[0107] Furthermore, in this example, according to the random pattern method, the number of the prepits with the minimum length that is the shortest mark (0.12 m) at the length equal to or less than the optical diffraction limit, Prepits of various lengths are arranged in order in the signal reproduction direction according to the rules defined by the standard. That is, in this embodiment, the shortest mark length (0.12 ^ 111 ) Prepits with several lengths are arranged according to the standard, so prepits with a mark length below the optical diffraction limit and prepits with a mark length longer than the optical diffraction limit are mixed. In other words, prepits that include a recording mark length that is less than or equal to the optical system resolution limit of the playback device and prepits that are longer than the optical system resolution limit of the playback device and have a recording mark length are mixed. Information is recorded at!

First, the results of measuring the C / N of the reproduction signal in the optical information recording media of Example 1, Comparative Example 2 and Comparative Example 3 are shown. At this time, C / N was measured when monopit pattern type prepits were reproduced that were prepits recorded on each optical information recording medium and having a length less than the optical diffraction limit and having a length of 0.12 m. . The measurement was performed with an optical disk evaluator having a wavelength of 406 nm, an objective lens numerical aperture of NAO. 85, and an upper limit of the reproduction laser power of 2. OmW.

The arrival C / N, which represents the C / N when the reproduction laser power increases and becomes saturated, was 42 dB in Example 1, 10 dB in Comparative Example 2, and 39 dB in Comparative Example 3. In general, it is said that an optical information recording medium can be put to practical use if the reaching C / N is 30 dB or more. Therefore, since Comparative Example 2 is a normal optical information recording medium that does not use super-resolution medium technology, the mark length below the optical limit cannot be reproduced. On the other hand, in Example 1 and Comparative Example 3, It can be seen that resolution reproduction is possible.

[0110] Next, the results of measuring the jitter of Example 1 and Comparative Examples 1 to 3 in the disk evaluator are shown. At this time, jitter was measured when a random pattern type prepit was reproduced with several types of prepits formed on the basis of the minimum length prepit (mark length 0.12 111).

FIG. 10 shows the change in jitter with respect to the reproduction light laser power in Example 1 and Comparative Examples 1 to 3.

[0112] First, Example 1 and Comparative Example 2 are compared. The jitter bottom value of Example 1 is about 7% lower than the jitter bottom value of Comparative Example 2. That is, it can be seen that the random pattern type optical information recording medium 2 having a mark with a length less than or equal to the optical diffraction limit can perform more stable super-resolution reproduction more efficiently than Comparative Example 2. .

[0113] Next, Example 1 and Comparative Example 1 are compared. As described above, Example 1 and Comparative Example 1 In addition, the jitter bottom is almost unchanged. However, the jitter becomes the bottom when the reproduction laser power is 0.5 mW in Example 1, and when the reproduction optical laser power is 1.6 mW in Comparative Example 1. That is, it can be seen that the reproduction laser power in Example 1 is 1/3 or less of the reproduction laser power in Comparative Example 1 and has a jitter bottom value. Therefore, the optical information recording medium 2 of Example 1 enables stable super-resolution reproduction with low power compared to the optical information recording medium 3 of Comparative Example 1.

[0114] Further, Example 1 and Comparative Example 3 are compared. Example 1 and Comparative Example 3 are recorded in a monotone pattern method, and the C / N when a prepit having a length less than the optical diffraction limit is reproduced has a good C / N value. It was found that resolution reproduction is possible.

[0115] However, in Comparative Example 3, compared to Comparative Example 2 in which super-resolution reproduction is not possible, as shown in FIG. 10, the random pattern method having a mark with a length less than or equal to the optical diffraction limit causes jitter to be reduced. It turns out that it is not reduced. That is, in Comparative Example 3, even when good C / N was obtained in the reproduction of a single frequency repetitive phase pit (monotone pattern method) of a mark having a length shorter than the optical diffraction limit, The random pattern method with the following lengths and marks longer than the optical diffraction limit reduces jitter! / ,! Thus, in an optical information recording medium on which information is recorded by a random pattern method in which a mark having a length less than the optical diffraction limit and a mark having a length longer than the optical diffraction limit are mixed, the C / N and jitter are not recorded. It can be said that the correlation is not necessarily established.

[0116] In other words, good C / N can be obtained with a mark having a length less than or equal to the optical diffraction limit. The power S that guarantees the reproduction characteristics, the information is recorded in a random pattern method that can be recorded at higher density! /, And the reproduction characteristics of super-resolution media are guaranteed! /, That's right! This means that in a super-resolution optical information recording medium that supports a random pattern method with a higher recording density, a recording mark with a length less than the optical diffraction limit and a recording mark with a length longer than the optical diffraction limit are evaluated for reproduction. This indicates that jitter evaluation is important.

[0117] The optical information recording medium 2 according to Example 1 is designed such that the wavelength distribution of the reflectance of the thin film portion 20 at room temperature satisfies min <λτ <λmax. To be In both cases, jitter is also reduced. That is, Example 1 is more stable than the optical information recording medium 3 according to Comparative Example 1, which is designed such that the wavelength distribution of the reflectance of the thin film portion 20 at room temperature is max≤λτ≤min. this and power ^s Wakakaru it is possible to perform super-resolution reproduction efficiently.

Next, an optical information recording medium in which the film thickness of the light absorption layer 22 of Example 1 was changed was produced, and the jitter of each optical information recording medium was measured using the disk evaluator. As shown in FIG. 11, the film thickness of the light absorption layer 22 is such that the jitter decreases as the film thickness increases.

[0119] If the thickness of the light absorption layer 22 is less than 5 nm, the film thickness is too thin, so that the reproduction durability when the reproduction light is incident cannot be ensured. Therefore, the film thickness of the light absorption layer 22 is preferably 5 nm or more.

Further, as shown in FIG. 11, when the thickness of the light absorption layer 22 is 5 nm or more, the jitter is reduced, but when the thickness is 50 nm or more, the jitter value is almost zero. Since it does not change, there is no further reduction in jitter. Therefore, it is preferable to set the thickness of the light absorption layer to 50 nm or more in order to ensure that the jitter is reduced.

However, as described above, when the light absorption layer 22 is formed by the sputtering method, when the film thickness of the light absorption layer 22 is greater than 500 nm, the unevenness of the prepits 31 on the substrate 30 is accurately determined. It will be impossible to reflect. Therefore, the film thickness of the light absorption layer 22 is preferably 500 nm or less.

Thus, by appropriately setting the film thickness of the light absorption layer 22, jitter can be reduced, that is, stable super-resolution reproduction can be performed efficiently. Further, when the thickness of the light absorption layer 22 is set to 50 nm or more and 500 nm or less, it becomes possible to reliably reduce the jitter.

[0123] In the optical information recording medium 1 and the optical information recording medium 2 that is an example thereof, the light transmitting layer 10, the thin film portion 20, and the substrate 30 are formed in this order from the reproduction light incident surface. Power that is not limited to this film formation.

[Embodiment 2]

Another embodiment of the present invention will be described as follows. Embodiment For members having the same function as 1, the same reference numerals are given, and the description thereof is omitted.

FIG. 12 is a cross-sectional view showing a schematic configuration of the optical information recording medium 6 of the present embodiment. Note that members having the same functions as those of the optical information recording media 1 and 2 are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 12, the optical information recording medium 6 includes a substrate 30 and a thin film portion 20, and is formed in this order from the reproduction light incident surface. The thin film portion 20 includes a reproducing layer 21 and a light absorbing layer 22 and is formed in this order from the reproducing light incident surface. That is, the optical information recording medium 6 is different from the optical information recording media 1 and 2 in that the light transmitting layer 10 that functions as a protective film is not formed.

[0127] The optical information recording medium 6 is not limited to the above configuration. For example, the optical information recording medium 6 further includes an intermediate layer (not shown) made of a transparent resin, and an information recording layer for recording and / or reproducing information. (Not shown) and the board | substrate 30 may be sufficient. This configuration conforms to the DVD (HD—DVD) standard.

[0128] Also in the optical information recording medium 6, the wavelength distribution of the reflectance of the thin film portion 20 at room temperature is

It is possible to set the thickness of the reproducing layer 21 in an appropriate range so that l min <λ τ <λ max. When the wavelength distribution is min <λ τ <λ max, the refractive index n and the extinction coefficient k of the reproducing layer 21 enhance the decrease in the reflectance of the thin film portion 20 when the temperature becomes high. Therefore, it is possible to reduce jitter. That is, the optical information recording medium 6 can efficiently perform stable super-resolution reproduction.

Further, the thin film portion 20 of the optical information recording medium 6 is similar to the optical information recording media 1 and 2 in the reproducing layer.

21 and the light absorption layer 22 are formed separately. Thereby, since the role is shared in the thin film portion 20, it is possible to improve the reproduction durability. In addition, since the optical information recording medium 6 performs optical reading through the substrate 30, even if the reproduction light incident surface of the substrate 30 is damaged, reading errors are unlikely to occur.

Accordingly, in the optical information recording medium according to the present embodiment, since the substrate is positioned on the side where the reproduction light is incident, the substrate functions as a protective film, and it is not necessary to separately provide a protective film or the like. . Therefore, optical information recording is cheaper than optical information recording media with a protective film or the like provided separately. A medium can be provided. In addition, since optical readout is performed through the substrate, it is possible to prevent reading errors even when the substrate on the reproduction light incident side is damaged.

[0131] The optical information recording media 1, 2 and 6 may be read-only optical information recording media composed of a read-only substrate, and information recording having a recording film on which information can be recorded. It can be an optical information recording medium! /.

[0132] Specifically, the optical information recording media 1, 2 and 6 are CD-ROM (Compact Disk Read Only Memory), D—R (and ompact Disk Recordable 8 CD—RAV (and ompact Disk Rewrita ble). ), DVD—ROM (Digital Versatile Disk Read Only Memory), DVD-RW (Digital Versatile Disk Rewritable), BD (Blu-ray Disc), BD—ROM, etc. Optically readable disc, magneto-optical disc, phase change The present invention can be applied to an optical disc such as a type disc, etc. The present invention is not limited to the recording method and the size of the optical information recording medium.

[0133] As described above, the first optical information recording medium according to the present invention is based on the change in the state of the light-transmitting layer and the optical multiple interference from the incident side of the reproduction light in order to solve the above problem. An optical information recording medium in which a thin film portion having a change in reflectance and a substrate on which information is recorded by a random pattern method corresponding to recording information and having a convex pattern and / or a concave pattern are sequentially stacked. Changes the state of optical multiple interference by changing the refractive index and extinction coefficient, which are the optical constants in the wavelength of the reproduction light, by increasing the temperature in order from the incident side of the reproduction light. And a light absorption layer that raises the temperature of the reproduction layer by absorbing a part of the incident reproduction light and converting it into heat, and has a reflectance of the thin film portion at room temperature. In the wavelength distribution, adjacent local minima and Wavelength to be Daine respectively, and min Oyobie max, when the e r the wavelength of the reproduction light, the relationship of λ πήη <λ r <λ max is satisfied.

[0134] In a random pattern type optical information recording medium including a recording mark with a length less than or equal to the optical diffraction limit produced using a conventional super-resolution technology, even when C / N is improved. Jitter is not always reduced. Therefore, reducing jitter is important for stable super-resolution reproduction. [0135] According to the above configuration, the translucent layer, the thin film portion, and the substrate are laminated in this order from the side on which the reproduction light is incident, and adjacent to each other in the reflectance wavelength distribution of the thin film portion at room temperature. The thin film portion is formed so that the relationship of min <λ τ <λ max is established, where the minimum and maximum wavelengths to be matched are min and max, respectively, and the wavelength of the reproduction light is r. Has been.

In this case, the refractive index at the high temperature of the reproducing layer constituting the thin film portion increases as compared with that at room temperature. Along with this, the wavelength distribution of the reflectance of the thin film portion at high temperature shifts to the longer wavelength side in the same manner as that at room temperature. The wavelength distribution of reflectance at room temperature of the thin film part is! /, Where the minimum and maximum adjacent wavelengths are min and max, respectively. Therefore, the reflectivity of the thin film portion at the wavelength r of the reproduction light decreases at a high temperature (see Fig. 1). Furthermore, as the extinction coefficient of the reproducing layer increases, the transmittance of the reproducing layer decreases. As a result, the extinction coefficient of the reproducing layer works to reduce the reflectivity of the thin film portion. In this way, each change in refractive index and extinction coefficient enhances the decrease in reflectivity of the thin film portion.

[0137] Therefore, in the high temperature region of the light spot of the reproduction light, both the refractive index and the extinction coefficient work to lower the reflectivity of the thin film portion, and the change in reflectivity is enhanced, thereby effectively reducing jitter. It will be possible to achieve this. That is, read errors occur in the reproduction system, and stable super-resolution reproduction can be performed efficiently, and the reproduction sensitivity of the optical information recording medium can be improved.

[0138] The wavelength distribution of the reflectance of the thin film portion depends on the film thickness of the thin film portion. For this reason, it is possible to form the thin film portion by setting the film thickness of the reproducing layer so that the relationship of max≤λλ≤min is established in the wavelength distribution of the reflectance of the thin film portion at room temperature. Noh. In this case, the refractive index n at a high temperature of the reproducing layer constituting the thin film portion increases as compared with that at room temperature. Along with this, the wavelength distribution of reflectance at high temperatures in the thin film part shifts to the longer wavelength side compared to that at room temperature (see Fig. 5). That is, since λ max approaches the wavelength λ r of the reproduction light, the reflectance of the thin film portion at the wavelength λ r of the reproduction light increases at a high temperature. However, at this time, the extinction coefficient k of the reproducing layer Increases, so the transmittance of the playback layer decreases. As a result, the extinction coefficient k of the reproducing layer works to reduce the reflectivity of the thin film portion. Thus, changes in the refractive index n and the extinction coefficient k do not enhance the reflectance change of the thin film portion. Therefore, it is preferable that the thin film portion has the structure according to the present invention!

[0139] Furthermore, since the wavelength distribution of the reflectance of the thin film portion depends on the film thickness of the thin film portion, the reflectance control of the optical information recording medium can be easily performed, and the production cost of the optical information recording medium is reduced. The power to make it becomes S Kanakura.

[0140] Furthermore, according to the above configuration, in the thin film portion, the reproducing layer that changes the state of optical multiple interference due to a temperature rise and the light absorption layer that raises the temperature of the reproducing layer are separately formed. Therefore, it is possible to improve the reproduction durability.

[0141] In order to solve the above-described problem, the second optical information recording medium according to the present invention uses the random pattern method of convex and / or concave corresponding to the recording information from the incident side of the reproduction light. Is an optical information recording medium in which a thin film portion whose reflectivity changes based on a change in the state of optical multiple interference is laminated, and the thin film portion is from the incident side of the reproduction light. In turn, as the temperature rises, the optical constant at the wavelength of the reproduction light, which changes the refractive index and extinction coefficient, changes the state of optical multiple interference, and the incident reproduction A light absorption layer that raises the temperature of the regeneration layer by absorbing part of the light and converting it into heat, and the adjacent local minimum value in the wavelength distribution of the reflectance of the thin film portion at room temperature And the maximum wavelength And min Oyo Bie max, when the e r the wavelength of the reproduction light, to establish the relationship min <λ τ <λ max

[0142] According to the above configuration, the substrate and the thin film portion are sequentially laminated from the side on which the reproduction light is incident, and the adjacent local minimum value and local maximum value in the wavelength distribution of the reflectance of the thin film portion at room temperature. The thin film portion is formed so that the relationship of min <λ τ <λ max is established, where min and e max are the wavelengths to be obtained, and r is the wavelength of the reproduction light.

In this case, the refractive index at the high temperature of the reproducing layer constituting the thin film portion increases as compared with that at room temperature. Along with this, the wavelength distribution of the reflectance of the thin film portion at high temperature shifts to the longer wavelength side in the same manner as that at room temperature. Thin film part at room temperature In the wavelength distribution of the reflectance, when the adjacent minimum and maximum wavelengths are min and max, respectively, λ min approaches the wavelength r of the reproduction light, so the wavelength of the reproduction light The reflectivity of the thin film portion at r decreases at higher temperatures (see FIG. 1). Furthermore, as the extinction coefficient of the reproducing layer increases, the transmittance of the reproducing layer decreases. As a result, the extinction coefficient of the reproducing layer works to reduce the reflectivity of the thin film portion. In this way, each change in refractive index and extinction coefficient enhances the decrease in reflectivity of the thin film portion.

[0144] Therefore, in the high temperature region of the light spot of the reproduction light, both the refractive index and the extinction coefficient work to lower the reflectivity of the thin film portion, and the change in reflectivity is enhanced, so that the jitter is efficiently reduced. It will be possible to achieve this. That is, read errors occur in the reproduction system, and stable super-resolution reproduction can be performed efficiently, and the reproduction sensitivity of the optical information recording medium can be improved.

[0145] Further, since the wavelength distribution of the reflectance of the thin film portion depends on the film thickness of the thin film portion, the reflectance control of the optical information recording medium can be easily performed, and the production cost of the optical information recording medium is reduced. The power to make it becomes S Kanakura.

[0146] Further, according to the above configuration, in the thin film portion, the reproduction layer that changes the state of optical multiple interference due to a temperature rise and the light absorption layer that raises the temperature of the reproduction layer are separately formed. Therefore, it is possible to improve the reproduction durability.

[0147] In the first and second optical information recording media of the present invention described above, the light absorption layer is preferably made of Si or Ge, or a mixture containing either of them as a main component. According to this, the temperature of the reproducing layer is effectively increased, and it is cheaper than organic dyes, semiconductors, metalloids, etc., and is easier to manage than phase change materials, and thus provides an inexpensive optical information recording medium. The power S

In the first and second optical information recording media of the present invention described above, the reproducing layer is preferably made of a metal oxide or a mixture containing the metal oxide as a main component. According to this, since the metal oxide is chemically stable, the metal oxide is not easily damaged by the incident reproduction light. For this reason, it becomes possible to improve the reproduction durability of the optical information recording medium. In addition, since metal oxides can be recovered as metals by reduction treatment, optical information recording It becomes possible to improve the recycling efficiency of the medium.

[0149] In the first and second optical information recording media of the present invention, the metal oxide is preferably zinc oxide or a mixture containing zinc oxide as a main component. According to this, since zinc oxide is a particularly chemically stable substance among metal oxides, it is not melted by the incidence of reproduction light. For this reason, zinc oxide is less susceptible to destruction due to the incidence of reproduction light than when other metal oxides are used for the thin film! For this reason, it becomes possible to further improve the reproduction durability of the optical information recording medium. In addition, zinc oxide is a low-cost metal oxide and has a low environmental impact. As a result, production costs can be reduced, and an environment-friendly optical information recording medium can be provided.

[0150] In order to solve the above problems, the third optical information recording medium according to the present invention has a translucent layer, a metal oxide, or a mixture containing the metal oxide as main components from the incident side of the reproduction light. The information is recorded by a metal oxide layer made of Si, Ge, or a thin film layer made of a mixture mainly composed of Si, Ge, or which force, and a random pattern method of convex and / or concave according to the recorded information. The optical information recording medium in which the substrate is laminated in order, and the wavelength distribution of the reflectance at the room temperature of the thin film portion composed of the metal oxide layer and the thin film layer, the wavelength having the adjacent minimum value and the maximum value is determined. When min and e max are set, and the wavelength of the reproduction light is r, the relationship of min λ τ <λ max is established.

[0151] According to the above configuration, the optical information recording medium has a metal oxide layer mainly made of a metal oxide and a thin film layer made of a mixture mainly composed of Si, Ge, or which force. And the thin film part is comprised by the said metal oxide layer and thin film layer.

[0152] Further, in the wavelength distribution of the reflectance of the thin film portion at room temperature, when the adjacent local minimum and local maximum wavelengths are min and max, respectively, and the reproduction light wavelength is r, The thin film portion is formed so that the relationship of l min <λΐ <λ max is established.

In this case, the refractive index at the high temperature of the reproducing layer constituting the thin film portion increases as compared with that at room temperature. Along with this, the wavelength distribution of the reflectance of the thin film portion at high temperature shifts to the longer wavelength side in the same manner as that at room temperature. The wavelength distribution of the reflectance of the thin film at room temperature! /, And the adjacent local minimum and local maximum wavelengths, When min and e max are set, λ min approaches the wavelength r of the reproduction light, so the reflectivity of the thin film portion at the wavelength r of the reproduction light decreases as the temperature rises (see FIG. 1). Further, as the extinction coefficient of the reproducing layer increases, the transmittance of the reproducing layer decreases. As a result, the extinction coefficient of the reproducing layer works to reduce the reflectivity of the thin film portion. In this way, each change in refractive index and extinction coefficient enhances the decrease in reflectivity of the thin film portion.

Yes

[0154] Therefore, in the high temperature region of the light spot of the reproduction light, both the refractive index and the extinction coefficient work to lower the reflectance of the thin film portion, and the change in reflectance is enhanced, so that the jitter is efficiently reduced. It will be possible to achieve this. That is, read errors occur in the reproduction system, and stable super-resolution reproduction can be performed efficiently, and the reproduction sensitivity of the optical information recording medium can be improved.

[0155] Further, since the wavelength distribution of the reflectance of the thin film portion depends on the film thickness of the thin film portion, the reflectance control of the optical information recording medium can be easily performed, and the production cost of the optical information recording medium is reduced. The power to make it becomes S Kanakura.

[0156] Further, according to the above configuration, in the thin film portion, the reproduction layer that changes the state of optical multiple interference due to the temperature rise and the light absorption layer that raises the temperature of the reproduction layer are separately formed. Therefore, it is possible to improve the reproduction durability.

In the fourth optical information recording medium according to the present invention, in order to solve the above-mentioned problem, information is recorded from the incident side of the reproduction light by a random pattern method composed of convex and / or concave according to the recorded information. And a metal oxide, or a metal oxide layer composed of the metal oxide as a main component, and a thin film layer composed of Si or Ge, or a mixture based on either of them. In the optical information recording medium laminated in order, in the wavelength distribution of the reflectance at room temperature of the thin film portion composed of the metal oxide layer and the thin film layer, adjacent minimum and maximum wavelengths are set to min and When max is set and r is the wavelength of the reproduction light, the relationship min <λ τ <λ max is established.

[0158] According to the above configuration, the optical information recording medium has a metal oxide layer mainly made of a metal oxide and a thin film layer made of a mixture mainly composed of Si or Ge, or which force. And the thin film part is comprised by the said metal oxide layer and thin film layer. [0159] Further, in the wavelength distribution of the reflectance of the thin film portion at room temperature, when the adjacent local minimum and local maximum wavelengths are min and max, respectively, and the reproduction light wavelength is r, The thin film portion is formed so that the relationship of l min <λ τ <λ max is established.

[0160] In this case, the refractive index at a high temperature of the reproducing layer constituting the thin film portion increases as compared with that at room temperature. Along with this, the wavelength distribution of the reflectance of the thin film portion at high temperature shifts to the longer wavelength side in the same manner as that at room temperature. The wavelength distribution of reflectance at room temperature of the thin film part is! /, Where the minimum and maximum adjacent wavelengths are min and max, respectively. Therefore, the reflectivity of the thin film portion at the wavelength r of the reproduction light decreases at a high temperature (see Fig. 1). Further, as the extinction coefficient of the reproducing layer increases, the transmittance of the reproducing layer decreases. As a result, the extinction coefficient of the reproducing layer works to reduce the reflectivity of the thin film portion. In this way, each change in refractive index and extinction coefficient enhances the decrease in reflectivity of the thin film portion.

[0161] Therefore, in the high temperature region of the light spot of the reproduction light, both the refractive index and the extinction coefficient work to lower the reflectivity of the thin film portion, and the change in reflectivity is enhanced, so that the jitter is efficiently reduced. It will be possible to achieve this. That is, read errors occur in the reproduction system, and stable super-resolution reproduction can be performed efficiently, and the reproduction sensitivity of the optical information recording medium can be improved.

[0162] Further, since the wavelength distribution of the reflectance of the thin film portion depends on the film thickness of the thin film portion, the reflectance control of the optical information recording medium can be easily performed, and the production cost of the optical information recording medium is reduced. The power to make it becomes S Kanakura.

[0163] Furthermore, according to the above configuration, in the thin film portion, the reproducing layer that changes the state of optical multiple interference due to a temperature rise and the light absorption layer that raises the temperature of the reproducing layer are separately formed. Therefore, it is possible to improve the reproduction durability.

In the third and fourth optical information recording media of the present invention described above, the metal oxide layer is preferably made of zinc oxide or a mixture containing zinc oxide as a main component. According to this, since zinc oxide is a particularly chemically stable substance among metal oxides, it does not melt when incident on the reproduction light. For this reason, zinc oxide is thin. It is less susceptible to damage due to the incidence of reproduction light than when other metal oxides are used for the film part. For this reason, it becomes possible to further improve the reproduction durability of the optical information recording medium. In addition, zinc oxide is an inexpensive metal oxide that has a low environmental impact. Therefore, the production cost can be reduced, and an environmentally conscious optical information recording medium can be provided.

[0165] The thickness of the reproducing layer is preferably 80 nm or more and less than 120 nm. If the thickness of the reproducing layer is less than 80 nm, it is considered that the effect of optical multiple interference cannot be obtained sufficiently! / And there is a possibility that stable super-resolution reproduction cannot be performed. In addition, when the thickness of the reproducing layer is 120 ηm or more, there is a thickness of the reproducing layer such that the minimum wavelength is around 400 ηm in the wavelength dependence of the reflectance of the thin film portion. In this case, for example, when reproducing an optical information recording medium in a Blu-ray optical system, there is a possibility that the reproducing layer cannot sufficiently obtain reflected light. For this reason, it is considered that the focus force S will be applied. Further, when the thickness of the reproducing layer is further increased, the reflectance of the thin film portion is considered to decrease the reproducing sensitivity because the heat supplied from the light absorbing layer is not sufficient when reproducing the optical information recording medium. .

[0166] According to the above configuration, since the above problem can be avoided, the optical information recording medium can be designed so that the relationship of min <λ τ <λ max is surely established. It becomes possible to reduce the jitter efficiently. In other words, stable super-resolution reproduction can be performed efficiently.

In addition, by setting the film thickness of the reproducing layer to 80 nm or more and less than 120 nm, jitter can be reduced, and the necessary power consumption of the reproducing light laser power can be reduced. As a result, it is possible to reduce the power consumption of the drive and to prevent deterioration of the reproducing optical element, and to prevent deterioration of the optical information recording medium due to irradiation of the reproducing light laser.

[0168] The thickness of the light absorption layer is preferably 5 nm or more and 500 nm or less. If the film thickness is less than 5 nm, it is considered that the reproduction durability cannot be ensured because the film thickness is too thin. In addition, when the thickness of the light absorption layer is made thicker than 500 nm, for example, when the light absorption layer is formed by the magnetron sputtering method, the atoms forming the light absorption layer evaporated by sputtering are completely on the substrate. It is not always perpendicular to the light. For this reason, the uneven pin on the substrate It is difficult to accurately reflect the network. Therefore, by setting the thickness of the light absorption layer to 5 nm or more and 500 ηm or less, it is possible to improve the reproduction durability and accurately reflect the uneven shape of the pit. Also, with the above configuration, jitter can be efficiently reduced and stable reproduction can be achieved.

[0169] The thickness of the light absorption layer is preferably 50 nm or more and 500 nm or less. As the film thickness of the light absorption layer increases, the jitter S is reduced, and when the film thickness of the light absorption layer is increased from 50 nm, the jitter reduction becomes approximately the same. Therefore, it is possible to reliably reduce jitter by setting the film thickness of the light absorption layer to 50 nm or more.

[0170] The optical information recording medium of the present application may be a reproduction-only optical information recording medium composed of a reproduction-only substrate, and an information-recordable optical information recording having a recording film capable of recording information is possible. It may be a medium.

[0171] As described above, the optical information recording medium according to the present invention has a thin film portion whose reflectance changes based on a change in the state of optical multiple interference, and the thin film portion is on the incident side of the reproduction light. More sequentially, as the temperature rises, a reproducing layer that changes the state of optical multiple interference as the refractive index and extinction coefficient, which are optical constants at the wavelength of the reproduced light, are changed. A light absorbing layer that absorbs a part of the reproduced light and converts it into heat to raise the temperature of the reproducing layer.

[0172] Further, as described above, the optical information recording medium according to the present invention has a metal oxide or a metal oxide layer composed of a mixture containing the metal oxide as a main component, and Si or Ge, or either of them. And a thin film portion made of the metal oxide and the thin film layer.

[0173] In the wavelength distribution of the reflectance of the thin film portion at room temperature, when the adjacent minimum and maximum wavelengths are min and max, respectively, and the wavelength of the reproduction light is r, min < Since the relationship of λ τ <λ max is established, jitter can be effectively reduced even in an optical information recording medium corresponding to recorded information and recorded information by a random pattern method consisting of convex and / or concave. Therefore, stable super-resolution reproduction can be performed efficiently. This produces an effect that an optical information recording medium with improved recording density can be provided. [0174] Furthermore, the optical information recording medium according to the present invention, corresponding to the recorded information, absorbs at least a part of the reproduced light in order on a substrate on which information is recorded in a random pattern consisting of convex and / or concave. A light-absorbing layer that is converted into heat, a reproducing layer that is heated by the heat generation of the light-absorbing layer, increases the refractive index n and extinction coefficient k at the wavelength of the regenerated light, and generates optical multiple interference; An optical information recording medium in which a light-transmitting layer is laminated and reproduction light is incident from the surface of the light-transmitting layer, and in the wavelength distribution of reflectance at room temperature of a thin film portion composed of the light-absorbing layer and the reproduction layer, When the adjacent minimum and maximum wavelengths are set to min and I max, the reproduction light wavelength r is set to be min λ τ <λ max. The light absorption layer is made of S, Ge, or a mixture containing either of them as a main component. Further, the reproduction layer is mainly made of a metal oxide, and the metal oxide layer is mainly made of zinc oxide.

[0175] In addition, optical multiple interference occurs sequentially on a substrate on which information is recorded in a random pattern consisting of convex and / or concave according to the recorded information, and the refractive index n at the reproduction light wavelength due to temperature rise. And a reproducing layer in which the extinction coefficient k increases and a light absorbing layer that absorbs part of the reproduced light and converts it into heat and supplies heat to the reproduced layer, and the reproduced light is incident from the substrate surface. In the wavelength distribution of the reflectance at room temperature of the thin film portion composed of the reproducing layer and the light absorbing layer, adjacent minimum and maximum wavelengths are represented by / L min and λ, respectively. When max is set, it is set so that 光生光 Ϊ 皮; ¾ λ r or L min <λ τ <λ max. Further, the light absorption layer is made of Si, Ge, or a mixture containing either of them as a main component. Furthermore, the reproduction layer is mainly made of a metal oxide. Further, the metal oxide layer is mainly composed of zinc oxide.

[0176] In addition, at least S or Ge, or a mixture containing either of them as a main component in order on a substrate on which information is recorded in a random pattern of convex and / or concave according to the recorded information. An optical information recording medium in which a thin film layer made of a material, a metal oxide layer mainly made of a metal oxide, and a light-transmitting layer are laminated, and reproduction light is incident from the surface of the light-transmitting layer, In the wavelength distribution of the reflectance at room temperature of the thin film layer and the thin film portion made of the metal oxide layer, when the adjacent minimum and maximum wavelengths are min and λ max, respectively, the reproduction light wave length r is obtained. Min is set so that λ τ <λ max. Also, the metal oxide layer Is mainly composed of zinc oxide.

[0177] In addition, on a substrate on which information is recorded in a random pattern composed of convex and / or concave according to the recorded information, a metal oxide layer mainly made of metal oxide, S or Ge, Alternatively, an optical information recording medium in which a thin film layer made of a mixture containing either of them as a main component is laminated and reproduction light is incident from the substrate surface, the thin film portion comprising the metal oxide layer and the thin film layer. In the wavelength distribution of reflectance at room temperature, when the adjacent minimum and maximum wavelengths are set to min and max, respectively, the reproduction light wavelength is set so that min <r <max. Yes. The metal oxide layer is mainly composed of zinc oxide. Furthermore, the thickness of the reproducing layer is 80 nm or more and less than 120 nm.

[0178] In the optical information recording medium according to the present invention, the thickness of the light absorption layer is 5 nm or more and 500 nm or less. Furthermore, the film thickness of the light absorption layer is 50 nm or more and 500 nm or less.

[0179] The specific embodiments or examples made in the detailed description section of the invention are to clarify the technical contents of the present invention, and are limited to such specific examples. Therefore, the present invention should not be interpreted in a narrow sense, and can be carried out with modifications within the spirit of the present invention and within the scope of the following claims! .

Industrial applicability

[0180] The optical information recording medium according to the present invention is applicable to both a read-only type having a concavo-convex recording surface on which information is recorded in advance and a type having a recording film capable of recording information. It is possible.

Claims

The scope of the claims

[1] From the incident side of the reproduction light, a translucent layer, a thin film portion whose reflectance changes based on a change in the state of optical multiple interference, and a random pattern consisting of convex and / or concave corresponding to recording information An optical information recording medium in which a substrate on which information is recorded by a method is sequentially laminated, and the thin film portion has an optical constant at a wavelength of the reproduction light as the temperature rises sequentially from the incident side of the reproduction light. A reproducing layer that changes the state of optical multiple interference with changing the refractive index and extinction coefficient;

A light absorption layer that raises the temperature of the reproduction layer by absorbing a part of the incident reproduction light and converting it into heat,

In the wavelength distribution of the reflectance of the thin film portion at room temperature, when the adjacent minimum and maximum wavelengths are min and max, respectively, and the wavelength of the reproduction light is r, An optical information recording medium characterized in that a relationship of min <λ τ <λ max is established.

[2] The optical information recording medium according to [1], wherein the light absorption layer is made of Si or Ge, or a mixture containing either of them as a main component.

[3] The optical information recording medium according to [1] or [2], wherein the reproduction layer is made of a metal oxide or a mixture containing the metal oxide as a main component.

[4] The optical information recording medium according to claim 3, wherein the metal oxide is zinc oxide.

[5] From the incident side of the reproduction light, the reflectance is based on the substrate on which the information is recorded by the random pattern of convex and / or concave corresponding to the recorded information and the change in the state of optical multiple interference. An optical information recording medium in which a changing thin film portion is laminated,

The thin film portion is in a state of optical multiple interference as the temperature rises in order from the incident side of the reproduction light and the refractive index and extinction coefficient, which are optical constants at the wavelength of the reproduction light, are changed. A playback layer that changes

In the wavelength distribution of the reflectance of the thin film portion at room temperature, the adjacent minimum and maximum wavelengths are min and max, respectively, and the reproduction light wavelength is r. An optical information recording medium wherein the relationship of min <λΐ <λmax is established.

6. The optical information recording medium according to claim 5, wherein the light absorption layer is made of Si or Ge, or a mixture containing either of them as a main component.

7. The optical information recording medium according to claim 5 or 6, wherein the reproduction layer is made of a metal oxide or a mixture containing the metal oxide as a main component.

8. The optical information recording medium according to claim 7, wherein the metal oxide is zinc oxide or a mixture containing zinc oxide as a main component.

[9] From the incident side of the reproduction light, a translucent layer, a metal oxide or a metal oxide layer made of a mixture containing the metal oxide as a main component, and Si or Ge, or one of the main components An optical information recording medium in which a thin film layer made of a mixture and a substrate on which information is recorded by a random pattern method consisting of convexes and / or concaves according to the recorded information are sequentially laminated, the metal oxide In the wavelength distribution of reflectivity at room temperature of the thin film part consisting of a layer and a thin film layer, the minimum and maximum adjacent wavelengths are denoted as min and max, respectively, and the wavelength of the reproduction light is defined as r. An optical information recording medium characterized in that a relationship of λ τ <λ max is established.

10. The optical information recording medium according to claim 9, wherein the metal oxide layer is made of zinc oxide.

[11] A substrate on which information is recorded by a random pattern method of convex and / or concave according to recorded information from the incident side of the reproduction light, and a metal oxide or the metal oxide as a main component An optical information recording medium in which a metal oxide layer made of a mixture and a thin film layer made of a mixture containing Si or Ge as a main component are sequentially laminated. The optical information recording medium comprises the metal oxide layer and the thin film layer. In the wavelength distribution of the reflectance of the thin film at room temperature, when the adjacent local minimum and maximum wavelengths are min and max, respectively, and the wavelength of the reproduction light is r, min λ τ <λ max An optical information recording medium characterized by

12. The optical information recording medium according to claim 11, wherein the metal oxide layer is made of zinc oxide or a mixture containing zinc oxide as a main component.

[13] The optical information recording medium according to any one of [1] to [12], wherein the thickness of the reproducing layer is not less than 80 nm and less than 120 nm.

[14] The optical information recording medium according to any one of [1] to [12], wherein the thickness of the light absorption layer is 5 nm or more and 500 nm or less.

[15] The optical information recording medium according to any one of [1] to [12], wherein the thickness of the light absorption layer is from 50 nm to 500 nm.