JP3454165B2 - Information recording medium and information recording method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium and an information recording method, and more specifically, at least one recording layer made of a single material in the information recording medium has a non-rewritable memory area and a rewritable memory area. And an information recording method for the information recording medium.

[0002]

2. Description of the Related Art Recently, in various information recording media represented by optical recording media and magnetic recording media, for example, (1) CD
For example, a non-rewritable memory such as a ROM disk is pre-recorded, or (2) CD-R is writable only once, and the written memory is not rewritable. Is referred to as a "write-once type"), or (3) a rewritable memory area such as an MD, etc., and various information recording media of various recording forms are provided according to the application. There is.

Of the above, the write-once type of (2) is such that a non-rewritable memory is recorded over the user's permission, and the non-rewritable memory is recorded in advance at the time of manufacturing (for the user's permission). 1) CD etc.,
As a result, the recording medium is considered to be of the same quality.

In such a situation, a single information recording medium in which any two or more memory areas of the above (1) to (3) are set together, especially the essence as a recording medium is different. (1) and / or (2) and (3)
If you can provide a memory area with
It is very convenient and the functions and uses of the information recording medium are significantly expanded.

In practice, the so-called "hybrid disc" type of conventional CD-R is (1)
And the memory areas of (2) are also set (for example, published by Ohmsha, co-authored by Heitaro Nakajima / Hiroshi Ogawa; see page 268 of "Compact Disc Reader-Revised 3rd Edition"),
Further, Japanese Patent Application Laid-Open No. 6-12714 discloses an information recording medium having a rewritable magneto-optical medium film on a ROM disk in which pit rows are formed.

[0006]

However, the above-mentioned "hybrid disc" type CD-R has a technically homogeneous (1) non-rewritable memory area,
Since only the write-once type memory area of (2) is made to coexist, there is little technical newness, and there is a certain limit to the expansion of the function and application as an information recording medium.

On the other hand, in the information recording medium disclosed in JP-A-6-12714, the non-rewritable memory area (1) and the rewritable memory area (3) coexist. Memory area is set in another recording layer of different material and composition. Therefore, ROM
The manufacturing process is complicated, such as the fact that a magneto-optical medium film must be further formed after forming the pit row of the disk,
There is a problem that the manufacturing cost also rises.

In addition, as far as the inventor of the present invention knows, an information recording medium in which the write-once type memory area of (2) and the rewritable memory area of (3) are coexistent has not yet been provided. Absent.

Therefore, according to the present invention, the memory area of (1) and / or (2) and the memory area of (3) are set together, and there is a problem in manufacturing process or manufacturing cost as described above. And an information recording method for the information recording medium,
It is a problem to be solved.

The inventor of the present application has completed the invention of the present application including these as an embodiment, taking the following and as specific triggers. In certain materials, the choice of optical information recording means causes irreversible shape change or chemical change (non-rewritable information recording) on the one hand, and reversible chemical or optical change on the other hand. (Rewritable information record)
It has been found that these changes can be used for recording and reproducing information. Furthermore, as a particularly preferable information recording means selection for these recording materials, it is possible to perform the above-mentioned two types of information recording by selecting the type and / or the intensity of polarized light as recording light in the same optical information recording system. I found it.

[0011]

(Structure of First Invention) The structure of the first invention of the present application (the invention according to claim 1) for solving the above problems is made of a single material in an information recording medium. At least one recording layer has a non-rewritable memory area for recording information based on an irreversible change in a recording bit portion, and a rewritable memory area for recording information based on a reversible change in a recording bit portion, It is a recording medium.

(Configuration of Second Invention) The configuration of the second invention of the present application (the invention according to claim 2) for solving the above-mentioned problems is as follows.
The non-rewritable memory area according to the first aspect of the present invention is an information recording medium, which is a write-once type memory area.

(Configuration of Third Invention) The configuration of a third invention of the present application (an invention according to claim 3) for solving the above-mentioned problems is as follows.
In at least one recording layer made of the single material according to the first invention or the second invention, information recording based on irreversible shape change or chemical change of the recording bit portion in the non-rewritable memory area by the optical recording means. And an information recording medium in which information is recorded in the rewritable memory area based on the reversible chemical change or optical change of the recording bit portion.

(Structure of Fourth Invention) The structure of a fourth invention of the present application (an invention according to claim 4) for solving the above-mentioned problems is as follows.
At least one recording layer in the information recording medium is capable of performing information recording based on irreversible shape change or chemical change of the recording bit portion and information recording based on reversible chemical change or optical change of the recording bit portion. The recording information based on an irreversible shape change or chemical change of the recording bit portion is formed in the non-rewritable memory area set in the recording layer by the selected optical information recording means constituted by using one material. An information recording method of recording recording information based on a reversible chemical change or optical change of a recording bit portion in a rewritable memory area set in the recording layer.

(Structure of the Fifth Invention) The structure of the fifth invention of the present application (the invention according to claim 5) for solving the above-mentioned problems is as follows.
The selection of the optical information recording means in the fourth invention is
In the same optical information recording system, it is a rewritable memory for selecting the kind and / or the intensity of the polarization of the recording light, and for the information recording based on the shape change of the recording bit portion in the non-rewritable memory area. This is an information recording method in which information recording based on rewritable optical anisotropy of a recording bit portion is performed in each area.

[0016]

[Operations and effects of the invention] (Operations of the first and second inventions
(Effect) In the first invention, since the information recording medium is provided with both the non-rewritable memory area and the rewritable memory area, it is possible to use the information recording medium in various ways which has not been available in the past, and its use is remarkably increased. To be extended.

As an extended example of such an application, in so-called game software, when the progress state of the game is recorded on another memory card, the first invention enables processing on one recording medium.

Further, according to the second aspect of the invention, a part or the whole of the non-rewritable memory area is a so-called write-once type memory area, which is suitable for high-mix low-volume production.
That is, a large amount of unrecorded same medium is prepared at the time of manufacturing the information recording medium, and each RO required at the time of sale is manufactured.
The M section can be written and sold as a medium in which the ROM section and the RAM section coexist. For example, in the case of a system in which the user can select and purchase only the desired data and program section at the time of purchase, there is a great merit that the ROM section desired by the user can be manufactured at the time of purchase.

In the first and second inventions, the non-rewritable memory area and the rewritable memory area are set in the same recording layer made of a single material in at least one recording layer. Therefore, there is no problem in the manufacturing process or the manufacturing cost as in the above-mentioned conventional technique.

(Operations and Effects of the Third and Fourth Inventions) In the third invention, in the recording layer made of the above-mentioned single material, the recording bit portion is irreversible in the non-rewritable memory area by the optical recording means. One possible embodiment is that information is recorded based on a physical shape change or chemical change, and information is recorded on a rewritable memory area based on a reversible chemical change or optical change of a recording bit portion. Provided.

That is, as in the fourth aspect of the invention, the optical information recording means is appropriately selected to perform information recording based on the irreversible shape change or chemical change of the recording bit portion in the non-rewritable memory area. If information recording is performed in the rewritable memory area based on reversible chemical change or optical change of the recording bit portion, the information recording medium of the first invention or the second invention can be easily and advantageously realized. You can

(Operation / Effect of Fifth Invention) In the fifth invention, when the information recording of the fourth invention is performed, the information recording means is selected such that the polarized light is recording light in the same optical information recording system. It is possible to perform information recording easily and at low cost because of the selection of the type (linearly polarized light, circularly polarized light, random polarized light, etc.) and / or intensity.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the first to fifth inventions will be described. In the following, simply "the present invention"
When referring to, the first to fifth inventions are collectively referred to.

[Information Recording Medium] In the information recording medium according to the present invention, at least one recording layer made of a single material has a non-rewritable memory area for recording information based on an irreversible change of a recording bit portion, and a recording bit. It has a rewritable memory area for recording information based on a reversible change of a portion (hereinafter, such a recording layer is referred to as a “recording layer of the present invention”). A plurality of such recording layers of the present invention may be provided, and in addition, a recording layer having another kind of arbitrary structure and function, a non-recording layer, a substrate, a protective film in consideration of crosstalk of recorded information, Components such as a light reflecting film and other film bodies may be optionally included.

The information recording medium according to the present invention has various known uses as a recording medium for optical information and other information, for example,
It can be used as a recording medium for computers, a recording medium for music or video, and the like.

As an example, it is possible to record the data of the electronic dictionary as the non-rewritable information and the citation frequency of the dictionary and the data added to the dictionary data by the user as the rewritable information.

As another example, a so-called karaoke music may be recorded as the non-rewritable information, and a song sung by the user according to the karaoke may be recorded as the rewritable information.

As yet another example, a program such as a word processor or presentation creation software is recorded as non-rewritable information, and a temporary file or user setting information when the program is executed is recorded as rewritable information. The usage form is also possible.

Furthermore, it can be used as a recording medium for any of various uses that have not yet been specifically assumed.

[Constitution of Recording Layer of the Present Invention] In the information recording medium, a single recording layer or a plurality of recording layers of the present invention are provided, and information is recorded in one layer or two or more layers in the single recording layer of the present invention. be able to. Furthermore, two or more layers (two sheets) of the recording layer of the present invention in which information is recorded in one layer or two or more layers may be joined by an appropriate means.

When a plurality of recording layers of the present invention are used, non-recording is made of a material having a constant light-transmitting property between all or some of these layers and which does not cause a photoreaction confusing with the recording layer of the present invention. The interposition of layers may be desired to reduce crosstalk.

The recording layer of the present invention comprises a single material (hereinafter, rewritable information recording based on irreversible change of recording bit portion and rewritable information recording based on reversible change of recording bit portion) This is referred to as "the recording material of the present invention").

In the recording layer of the present invention, only the non-rewritable memory area and the rewritable memory area are set, and the corresponding information may not actually be recorded yet.
The corresponding information may already be recorded in a part or all of the set non-rewritable memory area and / or the rewritable memory area.

When information is already recorded in a part or all of the non-rewritable memory area, that part is a memory area corresponding to a conventional CD, and the part of the non-rewritable memory area is partly or wholly. If no information has been recorded yet, that part is the conventional write-once type C.
This is a memory area corresponding to D-R.

The non-rewritable memory area and the rewritable memory area in the recording layer of the present invention may be set so as to be partitioned in the in-plane direction of the recording layer of the present invention, but in a single recording layer of the present invention. When recording information on two or more layers,
It may be set so as to be divided in the layer direction.

Further, such "setting of memory area" means
The non-rewritable memory area in the same portion of the recording layer of the present invention is not necessarily meant as a spatial area section, and on the assumption that the non-rewritable memory signal and the rewritable memory signal can be separated when necessary. The rewritable memory area may be set as multiple recording.

The setting of these memory areas may be determined in advance by the manufacturer, or may be set freely by the user. At that time, the “setting of the memory area” may be forcibly determined by some setting means (for example, the rewritable memory area of the medium is processed such that unrewritable information cannot be recorded). , The non-rewritable memory area is subjected to processing that cannot record rewritable information,
Etc.), there is no such compulsory setting process, and the user may actually be allowed to freely set the memory area as his own convention.

The form of information recording in the non-rewritable memory area is not limited as long as it is a non-rewritable form based on the irreversible change of the recording bit portion, but one of the typical recording forms is optical recording. It is information recording based on irreversible shape change or chemical change of the recording bit portion by means, and particularly preferably information recording based on shape change.

The recording means for recording such information is not limited, but one of the typical recording means causes decomposition, melting, reaction, etc. of the material by light irradiation, and irreversible shape change or chemistry based on this. To make a difference. One of the more particularly advantageous recording means is to cause a shape change by selecting the type and / or intensity of the polarization of the recording light in the same optical information recording system.

The form of information recording in the rewritable memory area is not limited as long as it is a rewritable form based on the reversible change of the recording bit portion, but one of the typical recording forms is an optical recording means. The information recording is based on the reversible chemical change or the optical change of the recording bit portion, and particularly preferably the information recording based on the rewritable optical anisotropy of the recording bit portion.

The recording means for recording such information is not limited, but one of the typical recording means is to cause a reversible chemical change or optical change in the recording bit portion by light irradiation. One of the particularly advantageous recording means is to induce a rewritable optical anisotropy by selecting the type and / or intensity of the polarization of the recording light in the same optical information recording system.

When the information recording in the non-rewritable memory area and the information recording in the rewritable memory area are performed by selecting the type and / or the intensity of the polarization of the recording light in the same optical information recording system, the same optical There is an advantage that desired information can be recorded in each memory area easily and at low cost simply by changing the type and / or the intensity of polarized light in the target information recording system.

[Constituent Material of the Recording Layer of the Present Invention] The recording layer of the present invention is composed of the recording material of the present invention as defined above.
The recording material of the present invention is a material capable of forming recording pits and the like as non-rewritable information recording by mechanical means such as injection molding or extrusion molding and any other means, and / or rewritable information. The record includes, for example, a material capable of forming a rewritable record of any form such as a magnetic record.

However, a typical example of the recording material of the present invention is information recording based on irreversible shape change or chemical change of a recording bit portion by an optical information recording means,
It is a material capable of recording information based on reversible chemical change or optical change of the recording bit portion.

Particularly preferable materials are information recording based on an irreversible shape change of the recording bit portion and rewritable optical anisotropy of the recording bit portion by selecting the kind and / or intensity of the polarized light which is the recording light. It is a material that can perform information recording based on each.

In the non-rewritable information recording, for example, the reflectance, the transmittance, the change in the refractive index and the reflectance, the transmittance, the anisotropy of the refractive index due to the progress of the above-mentioned irreversible shape change and chemical change. Changes can be used to identify information.

In rewritable information recording, for example, a change in the degree of orientation of the photoreactive component upon irradiation with linearly polarized light, a phenomenon such as a reversible photoisomerization reaction, etc. can be utilized. Information can be identified by using changes in reflectance, transmittance, refractive index and changes in reflectance, transmittance, and anisotropy of refractive index due to changes in degree and photoisomerization reaction.

In the non-rewritable memory area and / or the rewritable memory area, all recording information may be recorded by the same method or different methods. Here, the “method” means what kind of characteristics the recorded portion and the non-recorded portion are distinguished from each other. For example, a difference in refractive index, a difference in absorbance, a difference in reflectance, a difference in birefringence, etc. A method can be used. For example, information may be recorded in a certain area of the memory area by the difference in the refractive index, and information may be recorded in the other area by the difference in the absorbance.
The recording light for recording non-rewritable information and the recording light for recording rewritable information may have different wavelengths or intensities. The wavelengths of the recording light and the reading light are not particularly limited, but in practice, ultraviolet light, visible light, and near infrared light are preferable.

[Photoreactive Component] A typical embodiment when the recording material of the present invention as described above is viewed from the chemical structure side is as follows.
A material containing the above-mentioned various irreversible change component A and the above-mentioned various reversible change component B in an appropriate matrix, or the component C having the above-mentioned characteristics of the component A and the component B as appropriate. It is a material contained in a matrix (hereinafter, the components A to C are referred to as "photoreactive components").

As the photoreactive component, a photoisomerization component or a photopolymerizable component can be used. A photoreactive component having a large anisotropy of light absorption is more preferable.

For example, a polymer having both a photoreactive component which is decomposed by irradiation with a linearly polarized light having a wavelength of 500 nm and at the same time has absorption anisotropy, and a photoreactive component which causes optical poling by irradiation with a linearly polarized light having a wavelength of 700 nm. When a material is used, the former non-rewritable information recording and the latter rewritable information recording can be performed by properly using the linearly polarized light of these wavelengths.

If the non-rewritable information and the rewritable information can be read at different wavelengths and do not interfere with each other, it is determined whether the polarization directions of the light for recording and reproducing the information are the same. Regardless of this, it is possible to record / reproduce information of both parties independently of each other with light of different wavelengths.

On the other hand, if the non-rewritable information and the rewritable information can be read with the same wavelength light, the polarization directions of the recording light for recording the both information are set to different directions, and the reading light for the both information is read. By making the polarization directions of the two different, it is possible to record and reproduce the information of both independently.

Further, for example, "Chemical formula 1" to "Chemical formula 7" described later
The material of is equivalent to the above-mentioned C component, and when these are used, only the rewritable optical anisotropy is induced in the rewritable memory area by changing the linearly polarized light of low intensity to the recording light (rewritable (Information 1) can be recorded) and the optical anisotropy in different directions can be induced by changing the polarization direction of the linearly polarized light. By irradiating recording light of high intensity other than linearly polarized light (circularly polarized light, random polarized light, etc.), only a shape change can be introduced into the non-rewritable memory area (recording of non-rewritable information 2).

When the above information 1 and information 2 are recorded on the same recording bit by these methods, it is preferable to record the information 2 first and then the information 1. If the information is recorded in the reverse order, the previously recorded information 1 may be erased when the information 2 is recorded.

Further, by using high-intensity linearly polarized light as recording light, the same recording bits constituting the non-rewritable memory area and the rewritable memory area, which are redundantly set in the multiplex recording method, are simultaneously recorded on the same recording bits. Appropriate information recording can also be performed.

In the above description, the material capable of inducing the rewritable optical anisotropy by the recording light of linearly polarized light means that the absorption changes the orientation degree, the molecular structure, and the electronic state of the molecule. A material that causes reversible changes such as
There is no limitation as long as the optical anisotropy is changed by these. .

When information is recorded by optical anisotropy,
From the viewpoint of information recording and reading accuracy, a photoreactive component having a large anisotropy of light absorption is preferable. The direction B in which the change in the optical characteristics is induced with respect to the polarization direction A of the recording light differs depending on the type of the photoreactive component. However, even when A and B are in the same direction, It is sufficient if the recording light induces a change in optical characteristics in a predetermined direction B with respect to the direction A.

When a photoreactive component that causes a chemical reaction due to absorption of light is used, only the photoreactive component having a transition moment parallel to the recording light in the matrix selectively causes a chemical reaction, resulting in recording. The optical characteristics of the polarization direction parallel to the light change significantly.

When a photoreactive component such as azobenzene which causes trans-cis photoisomerization is used, the proportion of the photoreactive component having a transition moment almost perpendicular to the recording light increases as a result of optical poling. When the reading light having a polarization direction substantially perpendicular to the recording light is used, the optical characteristics of the reading light largely change due to the irradiation of the recording light.

In the rewritable memory area,
For the same recording bit, it is possible to induce multiple changes in optical characteristics in different directions by linearly polarized light in different polarization directions, and therefore information may be recorded in multiplex by this method.

The shape change of the recording bit portion in the non-rewritable memory area due to the irradiation of the recording light causes irreversible decomposition, melting, reaction, etc. of the material by the recording light of high intensity, which causes the shape change. It is a thing. It is preferable that the amount of change in the shape change is non-linear rather than linear with respect to the light intensity, that is, the shape change is caused by the light intensity equal to or higher than a certain threshold.

The change in shape of the recording bit can be detected by the principle of a normal laser displacement meter, or by the principle of an atomic force microscope. At this time, even if the same recording bit also has information recording by optical anisotropy, it can be detected without being interfered with and without destroying or degrading the recording. Further, by using the principle of the scanning near-field optical microscope, it is possible to detect the shape change and the optical anisotropy at the same time.

[Matrix Material] As a material for forming the matrix in the optical recording material of the present invention, an inorganic material such as glass can be used in addition to an ordinary organic material such as a polymer material. Considering the uniform dispersibility or binding property of the photoreactive component, the organic material,
Polymer materials are particularly preferable.

The photoreactive component includes a form in which the photoreactive component is simply dispersed in the matrix to a form in which it is firmly bound to the molecules constituting the matrix material by a chemical bond such as covalent bond or ionic bond. Even if the density of the photoreactive component is high by the design of the polymer structure, the distribution density in the matrix can be controlled to be almost completely uniform, and from the viewpoint of heat resistance or stability over time of the information recording medium, It is preferably chemically bonded. When the matrix is a polymeric material and the photoreactive component is chemically bonded to it, the photoreactive component may be incorporated into the backbone of the polymer and / or the side chains of the polymer. May be formed.

The type of the polymeric material as the material constituting the matrix is not limited, but a urethane group (-O-CO-NH- group) and a urea group (-
NH-CO-NH- group, -NH-CO-N <group, -NH
-CO-N〓 group) or an amide group (-CO-NH- group), or a polymer having a ring structure such as a phenylene group in the main chain of the polymer is heat-resistant. Particularly preferred.

Further, such a polymer material may be of any molecular weight and polymerization degree as long as it can be molded into a predetermined recording medium shape, and the polymerized form may be linear, branched, ladder-shaped, star-shaped or the like. It may be in the form of. The polymer may be a homopolymer or a copolymer. The form of the copolymer in the copolymer is also not limited, and may be a block copolymer, a random copolymer, a graft copolymer or any other.

From the viewpoint of recording stability, it is preferable that the glass transition temperature of the polymer material is high, and particularly when the information recording medium is used in a normal environment, the glass transition temperature is 100 ° C.
The above is preferable, but even if the glass transition temperature is about room temperature or lower, it can be used depending on the use environment of the information recording medium.

From the above points, as specific examples of the polymer material containing the photoreactive component, a few specific examples will be given. In addition to those described in Examples, the following "Chemical formula 1" to "Chemical formula 5" will be given.
Examples thereof include those having a polymer structure shown in. In these specific examples, -X is a nitro group, a cyano group, a trifluoromethyl group, an aldehyde group or a carboxyl group, and -Y- is -N = N-, -CH = N- or -CH = CH-, -R
-Indicates a phenylene group, an oligomethylene group, a polymethylene group or a cyclohexane group, respectively.

[0070]

[Chemical 1]

[0071]

[Chemical 2]

[0072]

[Chemical 3]

[0073]

[Chemical 4]

[0074]

[Chemical 5]

[0075]

EXAMPLES Next, examples of the present invention will be described.

( Synthesis of Photoreactive Component ) 2-Methyl-4-
Nitroaniline (30.43 g) and water (300 mL) and hydrochloric acid (36)
% Aqueous solution (180 mL) and dissolved in a mixed solution and cooled to 3 ° C. 15.20 g of sodium nitrite dissolved in 100 mL of water was added thereto. The resulting solution was kept at 3 ° C and stirred for 1 hour.

Furthermore, m-tolyldiethanolamine (39.05 g) and water (300 mL) and hydrochloric acid 36% aqueous solution 3 were added thereto.
A solution dissolved in a mixed solution with 0 mL was gradually added over 60 minutes, and then stirred at 3 ° C. for 150 minutes to react.

The reaction mixture was neutralized with 141.6 g of potassium hydroxide dissolved in 700 mL of water, the crude product was separated by filtration, washed with water and dried. Repeat recrystallization purification 3 times,
4-N, N-bis (2-hydroxyethyl) amino-2,2′-dimethyl-4′-nitroazobenzene represented by “Chemical Formula 6” was obtained (yield; 62%, melting point; 169 °).
C).

[0079]

[Chemical 6] ( Synthesis of Polymer Containing Photoreactive Component ) 2.000 g of the compound of "Chemical Formula 6" and 2.095 g of 4,4'-diphenylmethane diisocyanate were mixed in 50 mL of N-methyl-2.
-Dissolved in pyrrolidone, stirred at room temperature for 15 minutes to react, and further stirred at 100 ° C for 60 minutes to react. After cooling the solution to 50 ° C., 20 mL of N 2
Trans-2 dissolved in methyl-2-pyrrolidone,
0.319 g of 5-dimethylpiperazine was added, and the mixture was reacted for 5 hours with stirring. The mixture was further heated under reduced pressure to 115 ° C., and 52 mL of N-methyl-2-pyrrolidone was gradually distilled off over 150 minutes.

The reaction mixture obtained was diluted with 180 mL of pyridine and filtered through a 0.1 μm filter,
The polymer was poured into ethanol and the precipitated polymer was filtered off. The obtained polymer was purified twice by a reprecipitation method to obtain a polymer represented by "Chemical formula 7"(yield; 92%, glass transition temperature; 141 ° C, 30 in N-methyl-2-pyrrolidone).
Intrinsic viscosity at ° C; 0.69 dL / g, absorption maximum wavelength: 475 nm).

[0081]

[Chemical 7] ( Preparation of Recording Medium ) The polymer of "Chemical formula 7" was dissolved in pyridine to prepare a 6.5 wt% solution. The solution was spin-coated on a slide glass under the condition of a rotation speed of 1,000 rpm and vacuum dried at 80 ° C. for 20 hours to prepare a recording medium having a recording layer having a thickness of about 1 μm.

( Recording of Concavity and Convexity and Optical Anisotropy ) The recording layer of the above recording medium was irradiated with an argon laser having a wavelength of 488 nm to record non-rewritable information due to a change in the shape of the concavo-convex and optical anisotropy. The rewritable information was recorded by induction. The optical anisotropy was evaluated by a polarization absorption spectrum, and the shape change of the unevenness was evaluated by an atomic force microscope.

Recording 1: When circularly polarized light having high irradiation energy is irradiated to a predetermined portion of the recording layer, which is assumed to be a non-rewritable memory area, the surface of the recording layer is dented, and unrecordable information is recorded. I was able to do it.

Recording 2: When another predetermined portion of the recording layer assumed as a rewritable memory area is irradiated with linearly polarized light having low irradiation energy, the shape of the surface of the recording layer does not change from that before irradiation, and the optical shape is not changed. Only anisotropy could be induced. Then, when the same portion was irradiated with circularly polarized light having low irradiation energy, the induced optical anisotropy was erased.
That is, rewritable information could be recorded and erased.

Recording 3: Assuming that the predetermined portion of the recording layer on which the recording 1 is performed is a memory area in which the non-rewritable memory area and the rewritable memory area are set to overlap each other, this portion On the other hand, when linearly polarized light having a lower irradiation energy was irradiated, the dents on the surface of the recording layer were preserved and the optical anisotropy was induced in that part. Then, when the same portion was irradiated with circularly polarized light having a low irradiation energy, the induced optical anisotropy was erased, but the dent on the surface of the recording layer was still preserved.

Recording 4: A predetermined portion of the recording layer, which is assumed to be a memory area in which the non-rewritable memory area and the rewritable memory area are overlapped, is irradiated with linearly polarized light having high irradiation energy. The surface of the recording layer was dented, and at the same time, optical anisotropy was induced. When this portion was then irradiated with circularly polarized light having low irradiation energy, the induced optical anisotropy was erased, but the dents on the surface of the recording layer were preserved.

Front page continued (72) Inventor Riki Egami 15-100 Wago, Hamamatsu-shi, Shizuoka Prefecture (72) Inventor Hirohiro Sugihara 5-15 Uejima, Hamamatsu-shi, Shizuoka Prefecture (72) Naomichi Okamoto Masuraku-cho, Hamamatsu-shi, Shizuoka Prefecture Address 2578 (56) Reference JP-A-1-184640 (JP, A) JP-A-2-273341 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 7/24

Claims (5)

(57) [Claims] 1. At least one recording layer is a recording bit portion.
Non-rewritable information record based on irreversible change of minutes,
Rewritable information based on reversible change of recorded bit part
From a single material that can record multiple recordings at the same site
Information recording medium, characterized by comprising. 2. The information recording medium according to claim 1, wherein a part or all of the memory area for recording the non-rewritable information is a write-once type memory area. . 3. The at least one recording layer made of the single material can not be rewritten by an optical recording means.
In the memory area for recording information, information recording is performed based on irreversible shape change or chemical change of the recording bit part,
3. The information recording according to claim 1, wherein information is recorded based on a reversible chemical change or optical change of a recording bit portion in a memory area for recording rewritable information. Medium. 4. At least one recording layer of an information recording medium, information recording based on irreversible shape change or chemical change of a recording bit portion and information recording based on reversible chemical change or optical change of a recording bit portion. Is composed of a single material capable of multiple recording in the same portion, and the recording bit portion is formed in the memory area for performing non-rewritable information recording set in the recording layer by the selected optical information recording means. Information recording based on the irreversible shape change or chemical change of the recording layer is recorded on the same portion of the recording layer as the memory area where at least a part of the area is the non-rewritable information recording. Information recording based on reversible chemical change or optical change of the recording bit portion should be recorded in the memory area for rewritable information recording set redundantly. Information recording method characterized by. 5. The selection of the optical information recording means is selection of the type and / or intensity of polarized light that is recording light in the same optical information recording system, and the non-rewritable information recording is performed. the information recording based on the shape change of the recording bit portion in the memory area for a rewritable information recording
5. The information recording method according to claim 4, wherein information recording based on rewritable optical anisotropy of the recording bit portion is performed in each of the memory areas for performing the information recording.