JPH09306025A - Optical recording medium and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical recording medium capable of improving production efficiency and capable of performing a high density recording by forming a first recording layer whose optical characteristic is changed by being irradiated with a light having a first wavelength and a second recording layer whose optical characteristic is changed by being irradiated with a light having a second wavelength. SOLUTION: On the first recording layer 11 of an optical recording medium, a tracking area 31 and a data area 32 are provided by being separated and marks for tracking 33a, 33b and a synchronizing signal mark 34 are transferringly formed en bloc on the tracking area 31. The tracking marks 33a, 33b are formed at positions decentered at both sides a little from a track center line 38 in a pair an the synchronizing mark 34 is formed on the center line 38. Absorption rates in a wavelength 500-800nm of these marks are increased by the anisotropic reaction of photochromatic dystuff material due to the irradiating of a light, however, the absorption rate of a peripheral part is low and the transmissivity of the part is high. The form change of the recording layer 11 is not generated by the forming of tracking marks or the like. A second recording layer 13 is coated with dystuff material having the second wavelength while being formed on the recording layer 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium on / from which information signals can be additionally recorded or rewritten at high density, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a write-once type optical disc is known as an optical recording medium capable of recording information signals at high density. FIG. 2 shows a method of manufacturing such a conventional optical disc.
This will be described with reference to 0. The manufacturing process of an optical disc is roughly divided into two processes. One is the stamper manufacturing process, and the other is the disk duplication process.

In the stamper manufacturing process, first, a master 40 is prepared as shown in FIG. A glass disk is usually used as the master disk 40, and the surface thereof is polished.
Washed.

Next, as shown in (b), a photoresist film 41 is applied to the surface of the master 40 with a uniform thickness.

Master 4 coated with photoresist film 41
0 indicates that the information signal is recorded by the cutting device as shown in FIG. The information signal is recorded by rotating the master 40 and converging the laser light 45 modulated by the signal to be recorded and irradiating the photoresist film 41 with light to expose it. By gradually moving the irradiation position of the laser light 45 in the radial direction, the master 40
A tracking groove is formed in a spiral shape on the disk, and an address signal, a synchronization signal, and the like are similarly recorded if necessary.

The exposed master 40 is developed. As a result, as shown in FIG.
Only the exposed part of 1 is removed.

After the surface of the developed master 40 is made conductive, a thick electroformed film 42 made of a metal such as nickel is deposited and formed as shown in FIG.

When the formed electroformed film 42 is peeled off,
As shown in (f), a stamper 43 is completed, on the surface of which a row of spiral concaves and convexes corresponding to an address signal, a synchronizing signal, etc. and a groove for tracking are formed.

Next, the stamper 43 obtained by the above steps is used to mass-copy an optical disk. This step will be described below.

The stamper 43 is attached to the mold 44 of the injection molding machine as shown in (g). A transparent resin material such as PC (polycarbonate) or PMMA (polymethylmethacrylate) melted at high temperature is injected into the mold 44 to mold the substrate 46. After the substrate 46 is cooled, the center hole is punched out and taken out from the injection molding machine. On the surface of the substrate 46, as shown in (h), pits 47 on the surface of the stamper 43 in which irregularities are reversed and grooves for tracking are transferred and formed. Pit 4 formed
The length of 7 is usually about 0.4 μm to 2 μm, and the width of the tracking groove is usually about 0.4 μm to 1 μm.

On the surface of the taken-out substrate 46, as shown in (i), a recording layer 48 made of a cyanine dye or the like is applied and formed by a method such as spin coating. Further, if necessary, vapor deposition may be performed on the recording layer 48 as shown in (j).
The reflection film 49 made of metal such as gold or aluminum is formed by a method such as sputtering. Further, a protective film 50 made of a resin material is applied and formed on the reflective film 49 to complete the optical disc 51.

The optical disk 51 manufactured in this way
An information signal is recorded on the recording medium and the recorded information signal is reproduced by the recording / reproducing apparatus shown in FIG. Here, 1 is a spindle motor for rotationally driving the optical disk 51, 2 is an optical head, 8 is a reproducing circuit of an information signal, and 9 is a servo circuit. The optical head 2 includes a laser light source 3, a beam splitter 4, an objective lens 5, a detector 6, and an actuator 7 that drives the objective lens. When an information signal is recorded on the optical disc 51, the laser light source 3 is turned on while the optical disc 51 is rotationally driven by the spindle motor 1, and the high power laser light modulated by the information signal to be recorded is converted into the beam splitter 4. ,
Through the objective lens 5, the recording layer 48 of the optical disk 51 is converged and irradiated with a minute light spot. Holes (pits) are formed in the irradiated part of the laser light by the dye material that constitutes the recording layer absorbing the light and raising the temperature and causing thermal decomposition or melting.
Is formed. An information signal is recorded by associating a binary signal with the presence or absence of this pit.

Next, when reproducing the information signal recorded on the optical disk 51, the laser light source 3 is turned on while the optical disk 51 is rotationally driven by the spindle motor 1, and the low power laser light is directed to the beam splitter 4 and the objective. Through the lens 5, the recording layer 48 of the optical disc 51 is converged and irradiated with a minute light spot. The light reflected by the reflection film of the optical disc 51 is reflected by the beam splitter 4 and enters the detector 6. The detector 6 converts the amount of incident light into an electric signal and reproduces the information signal and the servo circuit 9
Output to The amount of light reflected by the reflective film changes depending on the pits of the recorded information signal, the preformed address signal, the pits of the synchronization signal, and the tracking groove.
As a result, the reproducing circuit 8 reproduces and outputs the information signal, the address signal, and the synchronizing signal from the output signal of the detector 6.

At the same time, the servo circuit 9 detects from the output signal of the detector 6 the displacement in the radial direction from the center of the track (pit row) at the light spot position and the displacement of the focus in the direction perpendicular to the surface of the optical disc 51. Based on this detection signal, a drive signal is output to the actuator 7, whereby the objective lens 5 is driven and control is performed so that the light spot always follows the track accurately.

Conventionally, in addition to the above-mentioned injection molding method, a substrate manufacturing method such as a compression molding method or a 2P (photopolymer) method is also known. In such a method as well, a stamper is used to form a substrate. It is the same as the injection molding method in that a groove for tracking and a pit for an address signal, a synchronization signal, etc. are transferred and formed.

[0016]

As described above, in the conventional write-once type optical disk, tracking grooves, address signals, pits for synchronization signals, etc. are formed on the substrate by the injection molding method. Therefore, even in this process, the time required is as long as 10 to 20 seconds for one substrate, so that the production capacity is low and it is not suitable for mass production. If mass production is required, a large number of injection molding apparatuses are required. Since it is necessary to prepare for it, a large amount of capital investment occurs, and there is a problem that the manufacturing cost cannot be reduced.

Since the substrates are manufactured by injection molding one by one as described above, the optical disks are processed one by one or in a small number in all subsequent steps,
Furthermore, it had to be transported to the next step, and there was a problem that the production efficiency was even worse.

Particularly, in the step of coating and forming the recording layer by spin coating, not only the time required for one sheet is as long as about 10 seconds, but also the constituent material of the recording layer (cyanine dye etc.) scattered around the disk at the time of coating. Since it is difficult to recover and recycle the material), the use efficiency of the material is extremely low at 10% or less, resulting in an increase in manufacturing cost.

Furthermore, in the above-mentioned injection molding method, it is difficult to form the tracking groove further narrower due to the limit of the transfer ability due to the fluidity of the resin material and the pits of the address signal and the synchronizing signal to be smaller. However, there is a problem that the recording density (track density and linear recording density) of the information signal cannot be increased.

Further, since the stamper deteriorates due to repeated use, it needs to be replaced each time, and a large number of stampers must be prepared when mass-producing optical discs.

The present invention has been made to solve the above-mentioned problems, and since tracking guides and marks, address signals, synchronization signal marks, etc. can be formed on a substrate in a short time, An object of the present invention is to provide an optical recording medium capable of improving production efficiency and capable of recording high density information, and a method for manufacturing the optical recording medium.

[0022]

That is, the present invention is made of a material whose light transmittance, reflectance, or absorptance is changed by irradiation with light having a first wavelength, and the first light is used. The first recording layer having the tracking guide or the tracking mark in which any of the light transmittance, the reflectance, and the absorptance is different from the surroundings due to the irradiation with the second irradiation with the light having the second wavelength. A second recording layer, which is formed of a material whose light transmittance, reflectance, or absorptance changes, and which can record an information signal by irradiation with the light of the second wavelength, is laminated on the substrate. And an optical recording medium.

Further, a step of forming a first recording layer made of a material whose light transmittance, reflectance or absorptance is changed on the substrate by irradiating light of the first wavelength, and Irradiating light having a wavelength of, and forming a tracking guide or a tracking mark in the first recording layer,
And a step of forming a second recording layer made of a material whose light transmittance, reflectance, or absorptance changes by irradiation with light of the second wavelength.

Further, in another invention of the present application, the light transmittance, the reflectance, and the absorptance of the light are changed between two states by the irradiation of the light of the first wavelength and the irradiation of the light of the second wavelength. And a tracking region having a tracking mark having a light transmittance, a reflectance, or an absorptance different from those of the surroundings by irradiation with light having a first or second wavelength. A light having a recording layer provided on a substrate, the recording layer having a data area having a data recording track capable of recording an information signal by irradiation with light having a wavelength of 1 or light having a wavelength of the second wavelength. Recording medium

Furthermore, the present invention provides a method of manufacturing an optical recording medium, which comprises a recording layer in which a tracking area and a data area in which an information signal can be recorded are formed separately. Forming a recording layer made of a material that changes between two states having different light transmittances, reflectances, or absorptivities due to light irradiation and light irradiation of a second wavelength; The layer is irradiated with the light of the first wavelength or the light of the second wavelength to form a tracking mark in the tracking region in which one of the light transmittance, the reflectance, and the absorptance is different from the surroundings, At the same time, the step of bringing the data recording track of the data area into a state in which the information signal can be recorded is included.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The first recording layer of the present invention has optical properties (light transmittance, reflectance,
Indicates either of the absorption rates. same as below. ) Is formed of a material such as a photochromic dye. As this material, a material whose optical characteristics change when irradiated with light of the second wavelength can be used. However, when a material whose optical characteristics do not change is selected, the tracking guide and the tracking mark have the second wavelength. Since it is not erased by the light, it is more preferable because the reliability is improved.

Further, since the tracking guide and the tracking mark in the first recording layer may have different optical characteristics from the surroundings, when forming this, the portion to be formed is irradiated with light, The state of the optical characteristics of this portion may be changed from the initial state, or the optical state of the surrounding portion may be changed from the initial state by irradiating light around the portion where the guides and marks are formed. But good.

The second recording layer of the present invention is formed of a material such as a photochromic dye whose optical characteristics change when it is irradiated with light of a second wavelength different from the light of the first wavelength. A rewritable recording medium can be realized by using a material that reversibly changes its state by irradiation with light having a third wavelength different from the second wavelength.

In such a two-layer recording layer,
The order of stacking the first recording layer and the second recording layer is such that the signal of the layer (upper layer) laminated thereon is read through the layer (lower layer) that is in close contact with the substrate so that the transmittance, reflectance, and absorptivity can be read. May be the lower layer or the upper layer if

The step of irradiating light of the first wavelength to form the tracking guide or the tracking mark in the first recording layer can be performed before or after forming the second recording layer. Is. That is, after forming the first recording layer, irradiation with light of the first wavelength may be performed to form a guide or mark for tracking, and the second recording layer may be formed thereon. In addition, after the first and second recording layers are continuously formed, light having a first wavelength is irradiated to the first recording layer.
It is also possible to form a tracking guide or mark in the recording layer. However, especially when the second recording layer is made of a material whose optical characteristics can be reversibly changed by irradiation with light having a third wavelength relatively close to the first wavelength, In order to prevent changes in the optical characteristics of the second recording layer due to light irradiation, it is preferable to form a tracking guide or the like on the first recording layer before forming the second recording layer.

In the present invention, the method of irradiating light is not particularly limited, and for example, it is possible to scan a laser beam to form a pattern such as a guide or mark for tracking, but normally, a guide or mark is used. It is preferable to collectively irradiate light through a mask having a pattern because the process can be completed in a short time.

The recording layer of a different invention of the present application is the first
The recording layer comprises a single recording layer made of a material such as a photochromic dye that changes between two states having different optical characteristics by irradiation with light having a wavelength of 2 and irradiation with light having a second wavelength. In this configuration, by providing the tracking area and the data area separately, the mark in the tracking area is not erased.

As the material which can be used in the present invention and whose optical characteristics are changed, photochromic dye materials are preferable, and diarylethene-based, spiropyran-based and fulgide-based organic dye materials are particularly preferable. For example, the compounds represented by formula (I) are preferable.

[0034]

Embedded image (In the formula, A and B are substituents selected from the groups represented by the following formula (II), and R ¹ to R in the formulas (I) and (II)
R ¹⁵ represents a substituent such as an alkyl group. )

[0035]

Embedded image

The application of this compound to the recording layer (first recording layer, second recording layer, etc.) of the present invention has the characteristics requiring the above-mentioned substituents A and B and substituents R ^{1 to} R ^15. It can be done by changing it together.

[0037]

EXAMPLES The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention.

[Embodiment 1] A first embodiment of an optical recording medium and a method of manufacturing the same according to the present invention will be described below with reference to the drawings. In this embodiment, the optical recording medium is an optical disc.

FIG. 1A shows an outline of the manufacturing process of the optical recording medium according to the present invention, and FIG. 1B shows the appearance of the optical recording medium in each process. Here, 10 is a substrate of the optical recording medium, which is made of a transparent resin, for example, a long sheet of polyethylene terephthalate, polyimide, polysulfone, polyphenylene sulfide, polycarbonate, polyester or the like. The width of the sheet is, for example, 80 to 150 mm, and the thickness is 0.05 to 0.8 mm. The substrate is wound around the delivery cylinder 18, and is delivered sequentially with the rotation of the delivery cylinder 18, and in the process of transportation, the first step (first recording layer formation), the second step (transfer), and the third step are performed. Step (second recording layer formation), fourth step (reflection film formation), fifth step
The optical disk 16 as an optical recording medium is continuously manufactured through the steps (protective film formation) and the sixth step (cutting). The surplus portion of the substrate 10 after cutting is wound around the winding cylinder 19. Hereinafter, each step will be described.

[First Step (Formation of First Recording Layer)] On the surface of the substrate 10 delivered from the delivery cylinder 18, first, the first recording layer 11 made of a photochromic dye material is formed by coating. The photochromic dye material used here has the property of changing its optical characteristics upon irradiation with light of the first wavelength. As examples of such materials, organic dye materials such as diarylethene-based, spiropyran-based, and fulgide-based materials are known, and these materials have a wavelength of 500.
When a light shorter than 1 nm (first wavelength) is irradiated, the dye energy causes an isomerization reaction of the dye molecule, and the absorptance at a wavelength of 500 to 800 nm increases. The material after the reaction is stable and has a wavelength of 500 to 800 nm.
Even if the light of the (second wavelength) is irradiated, the light transmittance, reflectance,
No change in absorption occurs.

The photochromic dye material is dissolved in a solvent and applied by a known method such as roll coating, blade coating or gravure coating, and then the solvent is volatilized to form a film having a thickness of 1 μm or less. If necessary, a photochromic dye material may be contained in a binder made of a resin material to form a coating.

The coating speed can be sufficiently high as 20 to 80 cm / sec (corresponding to 1 second or less per disk), and the use efficiency of the photochromic dye material is about 40%. High compared to conventional spin coating.

[Second Step (Transfer)] In the next step, 50
By irradiating a mask having a pattern such as a tracking mark or a tracking guide with light having a specific wavelength shorter than 0 nm and projecting an image of the pattern onto the first recording layer 11, the first recording layer Is exposed. As a result, a tracking mark, a tracking guide, or the like is transferred to the first recording layer 11.

This transfer process will be described in detail with reference to FIG. Here, 20 is a high pressure mercury lamp which is a light source, 2
Reference numeral 1 is a condenser lens, 22 is a mask, 23 is a reduction projection lens, and 24 is a stage.

An example of the structure of the mask 22 used here is shown in FIGS. 3, 4 and 8. 3 is an overall view, FIG. 4 is a partially enlarged view of an example of a mask on which a tracking mark pattern is formed, and FIG. 8 is a partially enlarged view of an example of a mask on which a tracking guide pattern is formed. 2A is a top view and FIG. 1B is a cross-sectional view. The mask 22 is a glass substrate 25 and Cr formed on the surface thereof.
The pattern 26 is made of a metal film such as.

In the example shown in FIG. 4, pattern 2
In FIG. 6, a known patterning technique is used, and the tracking marks 27a and 27b and the synchronization signal mark 28 are formed by the removed portion of the metal film. Here, the two tracking marks 27a and 27b are formed in pairs at positions slightly displaced from the track center line 30 to both sides, and the sync signal mark 28 is formed on the track center line 30. Here, a large number of such pairs of tracking marks and synchronization signal marks are formed on the spiral track. Address signal marks are also similarly formed as needed.

Further, in the example shown in FIG. 8, the tracking guide 29 is formed by the remaining portion after the metal film is removed. The tracking guide 29 is formed in a band shape on the track center line 30. Further, a synchronization signal mark and an address signal mark are also formed if necessary.

In the transfer process, as shown in FIG.
First, the substrate 10 is placed on the stage 2 with the first recording layer 11 facing upward.
It is fixed in close contact with the upper surface of 4. Stage 24 here
The upper surface of is processed with high flatness. The substrate 10 may be fixed in close contact with the stage 24 by using a method such as vacuum suction.

Next, light of a specific wavelength generated by the high-pressure mercury lamp 20, for example, g-line (wavelength 436 nm) or h-line (wavelength 405 nm) or i-line (wavelength 365 nm) is passed through the condenser lens 21 to the pattern 2 on the mask 22.
The entire surface of 6 is uniformly irradiated. Here, light is blocked at the remaining portion of the metal film of the pattern 26, and light is transmitted at the removed portion of the metal film. Therefore, the image of the pattern 26 is projected by the transmitted light through the reduction projection lens 23 onto the first recording layer 11. Here, the ratio of the image sizes of the pattern 26 and the pattern 26 projected on the first recording layer 11 is
It is about 5: 1 to 2: 1. In the image of the pattern 26 projected on the first recording layer 11, the photochromic dye material forming the first recording layer 11 reacts with the irradiated portion of the light transmitted through the removed portion of the metal film, and as a result, Wavelength 50
The absorption at 0-800 nm increases. On the other hand, the absorptance of the portion which is blocked by the remaining portion of the metal film and is not irradiated with light is not changed and is low.

FIGS. 5 and 9 show a partially enlarged view of the state of the optical recording medium after the pattern transfer using the masks shown in FIGS. 4 and 8. (A) is a top view and (b) is a sectional view.

In the example shown in FIG. 5, a tracking area 31 and a data area 32 are provided separately in the recording layer 11 of the optical recording medium, and tracking marks 33a and 33 are provided.
b and the synchronization signal mark 34 are collectively formed on the tracking area 31 of the first recording layer 11 by transfer. Here, the two tracking marks 33a and 33b are formed in pairs at positions slightly displaced from the track center line 38 to the both sides, and the synchronization signal mark 34 is formed on the track center line 38. Here, a large number of such pairs of tracking marks and synchronization signal marks are formed on the spiral track.

The portions of the tracking marks 33a and 33b and the synchronization signal mark 34 have wavelengths of 500 to 500 as a result of the isomerization reaction of the photochromic dye material by irradiation of light.
The absorption at 800 nm is increasing. In addition, a portion around the portion not irradiated with light has a low absorptance and a high transmittance. Further, the data area 32 also has a low absorptivity and a high transmittance. Incidentally, in the formation of such tracking marks and synchronization signal marks, the shape change of the first recording layer 11 is not accompanied.

In the example shown in FIG. 9, the first recording layer 1
A tracking guide 35 is collectively transferred and formed on the sheet 1 by irradiation of light. Tracking guide 35
Are formed in a band shape on the track center line 38. The portion of the tracking guide 35 is not irradiated with light, and the extension 5
It has a low absorptance at 00 to 800 nm and a high transmittance. Further, in the portion between the tracking guides 35, as a result of the isomerization reaction of the photochromic dye material by irradiation of light, the absorptance at a wavelength of 500 to 800 nm increases.

[Third Step (Formation of Second Recording Layer)] In the next step, the second recording layer 13 is formed. 6 and 1
0 is a partially enlarged view of the state after the second recording layer 13 is formed in the optical recording medium in which the pattern is transferred using the masks shown in FIGS. 4 and 8. (A) is a top view and (b) is a sectional view. Second made of photochromic dye material
The recording layer 13 is formed by coating on the first recording layer 11. The photochromic dye material used here is the second
It has the property of changing its optical characteristics by irradiation with light of this wavelength. As examples of such materials, organic dye materials such as diarylethene-based, spiropyran-based, and fulgide-based materials are known, and these materials have wavelengths of 500 to 800.
When a high-power light of nm (second wavelength) is irradiated, the dye molecule causes an isomerization reaction due to the energy of the light,
The absorptance at a wavelength of 500 to 800 nm decreases. If necessary, before or after coating and forming the second recording layer, these materials are irradiated with light having a wavelength shorter than 500 nm (third wavelength), and the dye energy is isomerized by light energy. A reaction is caused to occur, and the wavelength is 500 to 800 nm.
It is advisable to keep the absorption rate in water in an increased state. Further, here it is desirable to use a material having a characteristic that it reacts when irradiated with high power light but does not react when irradiated with low power light.

The photochromic dye material is dissolved in a solvent and applied by a known method such as roll coating, blade coating or gravure coating, and then the solvent is volatilized to form a film having a thickness of 1 μm or less. If necessary, a photochromic dye material may be contained in a binder made of a resin material to form a coating.

[Fourth Step (Reflection Film Formation)] In the next step, the reflection film 14 is formed on the second recording layer 13. The reflective film 14 may be formed into a thin film by vacuum-depositing a material having a high reflectance, for example, a metal such as Al, or may be formed by coating a material such as a pigment material having a relatively high reflectance. If the reflectance of the second recording layer 13 itself is sufficiently high, it is not necessary to form the reflective film 14.

[Fifth Step (Protective Film Formation)] In the next step, a protective film 15 made of a resin material or the like is applied and formed on the reflective film 14. If the first recording layer 11, the second recording layer 13, and the reflective film 14 have sufficiently high corrosion resistance, it is not necessary to form the protective film 15.

[Sixth Step (Cutting)] In the next step, the substrate is cut into a predetermined shape and the optical disk 16 which is an optical recording medium.
Is completed. Here, as an example, the optical disc 16 has a diameter of 50 to 120 mm, and at the same time, a central hole 17 for mounting the recording / reproducing apparatus is provided at the center of the optical disc 16. Generally, a cut portion used for positioning the optical recording medium and the recording / reproducing apparatus, for example, a center hole in an optical disc, is required to have relative positional accuracy with respect to a tracking mark or a tracking guide. Therefore, in the second step (transfer), the positioning mark for cutting is transferred and formed together with the tracking mark or the tracking guide, and this positioning mark is optically detected in the cutting step. The substrate 10 may be positioned in the cutting device by the so that the cutting is performed with high positional accuracy.

Alternatively, the centering hole or the like may be cut using a cutting device in a state where the tracking mark or the tracking guide or the like is fixed during transfer. In this case, the relative positional accuracy between the center hole and the transferred tracking marks, tracking guides, and the like is almost determined only by the positional accuracy between the mask and the cutting processing device. If you adjust and fix the cutting device with high position accuracy,
It is not necessary to detect and position the cutting position of the substrate with high position accuracy each time the cutting process is performed, and a center hole with sufficiently high relative position accuracy with respect to the tracking marks and tracking guides is formed. Of.

The optical disc manufactured in this way is
Recording and reproduction are performed by a recording / reproducing apparatus similar to the conventional recording / reproducing apparatus shown in FIG.

FIG. 7 is a partially enlarged view of the state after recording the information signal of the optical disc on which the pattern is transferred using the mask shown in FIG. (A) is a top view and (b) is a sectional view. When recording the information signal in the data area 32 of the optical disc, the wavelength of 500 is applied from the substrate side 10 of the optical disc.
At ˜800 nm, a high power laser beam modulated by an information signal is irradiated onto the recording layer while converging it into a minute light spot.
In the data area 32, the photochromic dye material forming the second recording layer reacts at the portion of the second recording layer 13 which is transmitted through the first recording layer 11 and irradiated with the laser beam,
As a result of the decrease in the absorptance at the wavelength of 500 to 800 nm, the data recording track 3 provided in the data area 32
An information signal mark 37 is formed at 6.

Next, when reproducing the information signal thus recorded, a low power laser beam having a wavelength of 500 to 800 nm is irradiated onto the recording layer of the optical disc while converging it into a minute light spot. The portions of the tracking marks 33a and 33b and the synchronization signal mark 34 formed on the first recording layer 11 have an absorption rate at a wavelength of 500 to 800 nm higher than that of the surroundings, and are formed on the second recording layer 13. The information signal mark 37 has a wavelength of 500 to 8
The absorptance at 00 nm is lower than that of the surroundings. Therefore, the amount of light reflected by the reflection film 14 of the optical disk changes depending on the tracking marks 33a and 33b, the synchronization signal mark 34, and the information signal mark 37. Therefore, the information signal recorded in the data area 32 can be reproduced by detecting the change in the light amount of the reflected light, and the signal reproduced from the pair of tracking marks 33a and 33b in the tracking area 31 can be used to reproduce the light spot position. A displacement in the radial direction from the track center line 38 is detected, and tracking control is thereby performed. The signal reproduced from the sync signal mark 34 is used for recording and reproducing the information signal in the data area 32.

Next, FIG. 11 is a partially enlarged view of the state after recording the information signal of the optical disc on which the pattern is transferred using the mask shown in FIG. When recording the information signal, the wavelength is 500 to 800 nm from the substrate 10 side of the optical disc.
Then, a high-power laser beam modulated by an information signal is focused on a small light spot on the recording layer and irradiated. The light is transmitted through the tracking guide 35 formed on the first recording layer 11,
The portion where the second recording layer 13 is irradiated with the laser beam is the second
The information signal mark 37 is formed as a result of the photochromic dye material forming the recording layer 13 reacting, and the absorptance at a wavelength of 500 to 800 nm being smaller than that of the surroundings.

Next, when reproducing the information signal recorded in this way, a laser beam having a wavelength of 500 to 800 nm and a low power is focused on a recording layer of the optical disc and irradiated with a minute light spot. The portion of the information signal mark 37 formed on the second recording layer 13 has a wavelength of 500 to 800 nm.
The absorption rate at is lower than that of the surroundings. Therefore, the amount of light reflected by the reflective film 14 of the optical disk changes depending on the information signal mark 37. Therefore, the information signal recorded can be reproduced by detecting the change in the light amount of the reflected light. Further, the portion of the tracking guide 35 formed on the first recording layer 11 has a low absorptance at a wavelength of 500 to 800 nm, and the portion between the tracking guides has a high absorptivity. Therefore, the displacement of the light spot position from the track center line 38 in the radial direction is detected from the reflected light, and the tracking control is performed thereby.

Here, in the present embodiment, the recording layer is composed of two layers, and the photochromic material constituting the first recording layer has a light transmittance, a reflectance, Since the change in the absorptance does not occur, the tracking mark, the synchronization signal mark, the tracking guide, etc. will not be erased if light with a wavelength of 500 to 800 nm is used for reproduction. The second recording layer also has a wavelength of 500.
Reacts by irradiation of high power light at ~ 800 nm,
The information signal mark is not erased by reproduction if it is made of a photochromic material having a property of not reacting when irradiated with low power light.

The second recording layer is formed with a wavelength of 500 to 800.
Irradiation of light of nm (second wavelength) and a wavelength different from the second wavelength, for example, a wavelength shorter than 500 nm (third wavelength)
Of light having a second wavelength and a light having a third wavelength are used for recording and erasing information signals. Then, not only a write-once type optical recording medium but also a rewritable type optical recording medium can be realized.

[Embodiment 2] A second embodiment of the optical recording medium and the manufacturing method thereof according to the present invention will be described below with reference to the drawings. The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Also in this embodiment, the optical recording medium is an optical disk.

FIG. 12A shows the outline of the manufacturing process of the optical recording medium according to the present invention, and FIG. 12B shows the appearance of the optical recording medium in each process. The substrate is sequentially delivered as the delivery cylinder 18 rotates, and in the process of transportation, the first process (recording layer formation), the second process (transfer), the third process (reflection film formation), and the fourth process (protection) are performed. After the film formation) and the fifth step (cutting), the optical disk 16 as an optical recording medium is continuously manufactured.

[First Step (Formation of First Recording Layer)] On the surface of the substrate 10 delivered from the delivery cylinder 18, a recording layer 12 made of a photochromic dye material is first applied and formed. The photochromic dye material used here has the property of changing between two states having different optical characteristics upon irradiation with light having a first wavelength and irradiation with light having a second wavelength. As examples of such materials, organic dye materials such as diarylethene-based, spiropyran-based, and fulgide-based materials are known, and these materials have a wavelength of 500 n.
When a light shorter than m (first wavelength) is irradiated, the dye molecule causes an isomerization reaction due to the energy of the light, and the absorptance at a wavelength of 500 to 800 nm increases. When light with a wavelength of 500 to 800 nm (second wavelength) is further irradiated, the molecules of the dye cause an isomerization reaction, and the wavelength of 500
The absorptance at ~ 800 nm decreases and returns to the original state.

The photochromic dye material is dissolved in a solvent and applied by a known method such as roll coating, blade coating or gravure coating, and then the solvent is volatilized to form a film having a thickness of 1 μm or less. If necessary, a photochromic dye material may be contained in a binder made of a resin material to form a coating.

The coating speed can be sufficiently high as 20 to 80 cm / sec (corresponding to 1 sec or less per disk), and the use efficiency of the photochromic dye material is about 40%. High compared to conventional spin coating.

[Second Step (Transfer)] In the next step, 50
Tracking marks with a specific wavelength of 0 nm or less,
The recording layer is exposed by irradiating a mask having a pattern such as sync signal marks and data recording tracks and projecting an image of the pattern onto the recording layer. As a result, tracking marks, synchronization signal marks, data recording tracks, etc. are transferred to the recording layer.

The transfer process is almost the same as that of the first embodiment and is as shown in FIG. The overall structure of the mask used here is as shown in FIG. 3, and is composed of the glass substrate 25 and the pattern 26 formed on the surface of the metal film such as Cr. 13 and 16 are partially enlarged views of an example of a mask on which patterns of tracking marks and synchronization signal marks are formed. In each drawing, (a) is a top view,
(B) is a sectional view.

In the example shown in FIG. 13, the tracking marks 27a, 2a are formed by the remaining portion of the metal film, and in the example shown in FIG.
7b and the synchronization signal mark 28 are formed. Here, the two tracking marks 27a and 27b are formed in pairs at positions slightly displaced from the track center line 30 to both sides, and the sync signal mark 28 is formed on the track center line 30. Here, a large number of such pairs of tracking marks and synchronization signal marks are formed on the spiral track. Address signal marks are also similarly formed as needed.

Further, in the example shown in FIG. 16, the data recording track 39 is formed by the removed portion of the metal film. The data recording track 39 includes a pair of tracking marks and a sync signal mark, and one mark before or after the mark.
It is formed between the pair of tracking marks and the synchronization signal mark, and is formed in a band shape on the track center line 30.

In the transfer process, as shown in FIG.
First, the substrate 10 is fixed to the upper surface of the stage 24 with the recording layer 12 facing upward. Here, the upper surface of the stage 24 is processed with high flatness. The substrate may be fixed in close contact with the stage 24 by using a method such as vacuum suction.

Next, light of a specific wavelength generated by the high-pressure mercury lamp 20, for example, g-line (wavelength 436 nm) or h-line (wavelength 405 nm) or i-line (wavelength 365 nm) is passed through the condenser lens 21 to the pattern 2 on the mask 22.
The entire surface of 6 is uniformly irradiated. Here, light is blocked at the remaining portion of the metal film of the pattern 26, and light is transmitted at the removed portion of the metal film. Therefore, the image of the pattern 26 is projected on the recording layer 12 through the reduction projection lens 26 by the transmitted light. Here, the ratio of the image sizes of the pattern 26 and the pattern 26 projected on the recording layer 11 is about 5: 1 to 2: 1. In the image of the pattern 26 projected on the recording layer 12, the photochromic dye material forming the recording layer 12 reacts with the irradiated portion of the light transmitted through the removed portion of the metal film, and as a result, absorption at a wavelength of 500 to 800 nm. The rate increases. On the other hand, the absorptance of the portion which is blocked by the remaining portion of the metal film and is not irradiated with light is not changed and is low.

FIGS. 13 and 1 are shown in FIGS. 14 and 17.
The state of the optical recording medium after the pattern transfer is performed using the mask shown in FIG. (A) is a top view,
(B) is a sectional view. In these examples, a tracking area 31 and a data area 32 are separately provided in the recording layer 12 of the optical recording medium.

In the example shown in FIG. 14, the tracking marks 33a and 33b and the synchronization signal mark 34 are
It is transferred and formed collectively on the tracking area 31 of the recording layer 12. Here, the two tracking marks 33
The a and 33b are formed in pairs at positions slightly displaced from the track center line 38 on both sides, and the sync signal mark 34 is formed on the track center line 38. Here, a large number of such pairs of tracking marks and synchronization signal marks are formed on the spiral track.

The areas around the tracking marks 33a and 33b and the synchronizing signal mark 34 in the tracking area 31 and the data area 32 are wavelengths 500 to 8 as a result of the isomerization reaction of the photochromic dye material by the irradiation of light.
The absorption rate at 00 nm is increasing. Data area 3
In No. 2, the absorptance is increased in the entire area including the data recording track 36 where the information signal is recorded.
Further, the portions of the tracking marks 33a and 33b and the synchronization signal mark 34 are not irradiated with light, and the absorptance does not change and is low. It should be noted that in the formation of such tracking marks and synchronization signal marks, the shape of the recording layer 12 does not change.

In the example shown in FIG. 17, the tracking marks 33a and 33b and the synchronization signal mark 34 are collectively formed on the tracking area 31 of the recording layer 12, and the data recording track 36 is formed on the data area 32 at one time. . Here, the two tracking marks 33a, 33
b are formed in pairs at positions slightly displaced from the track center line 38 on both sides, and the sync signal mark 34 is formed on the track center line 38. The data recording track 36 is formed between a pair of sync signal marks and a pair of sync signal marks before or after the sync signal mark, and is formed in a band shape on the track center line 38. Here, many pairs of such tracking marks, synchronization signal marks, and data recording tracks are formed on a spiral track.

The tracking marks 33a and 33b and the synchronizing signal mark 34 in the tracking region 31 have an increased absorptance at a wavelength of 500 to 800 nm as a result of the isomerization reaction of the photochromic dye material by irradiation of light. Data recording track 3 in the data area 32
The portion 6 also has an increased absorptance at a wavelength of 500 to 800 nm due to light irradiation. In addition, the tracking mark, the synchronization signal mark, and the portion around the data recording track are not irradiated with light, and the absorptance is low.

[Third Step (Reflective Film Formation), Fourth Step (Protective Film Formation), Fifth Step (Cutting)] The third to fifth steps can be performed in the same manner as in Example 1.

The optical disc manufactured in this way is
Recording and reproduction are performed by a recording / reproducing apparatus almost similar to the conventional recording / reproducing apparatus shown in FIG. FIGS. 15 and 18 show a partially enlarged view of a state after information signal recording of the optical recording medium on which the pattern has been transferred using the masks shown in FIGS. (A) is a top view and (b) is a sectional view.

When recording an information signal in the data area 32 of the optical disc, a high power laser beam having a wavelength of 500 to 800 nm and modulated by the information signal is minutely recorded on the recording layer 12 from the substrate 10 side of the optical disc. Irradiate after converging to a special light spot. As shown in FIGS. 15 and 18, the wavelength 50
Data region 3 with increased absorption at 0-800 nm
In the data recording track 36 of No. 2, the photochromic dye material reacts with the portion irradiated with the high-power laser beam, and the absorptance at the wavelength of 500 to 800 nm decreases, so that the information signal mark 37 is formed.

Next, when reproducing the information signal recorded in this way, a low power laser beam having a wavelength of 500 to 800 nm is irradiated onto the recording layer 12 of the optical disc while converging it into a minute light spot. In the example shown in FIG. 15, in the tracking area 31 of the recording layer 12, the portions of the tracking marks 33a and 33b and the synchronization signal mark 34 have a low absorptance at a wavelength of 500 to 800 nm, and the surrounding portions have an increased absorptivity. ing. In the example shown in FIG. 18, in the tracking area 31 of the recording layer 12, the tracking marks 33a and 33b and the synchronization signal mark 34 have an increased absorptance at a wavelength of 500 to 800 nm, and the surrounding portions have an absorptivity. Low. In addition, in both the examples shown in FIG. 15 and FIG.
An information signal mark 37 having a reduced absorption rate is formed on the data recording track 36 of FIG. Therefore, the amount of light reflected by the reflective film 14 of the optical disk changes due to the tracking marks 33a and 33b, the synchronization signal mark 34, and the information signal mark 37. Therefore, the information signal recorded in the data area 32 can be reproduced by detecting the change in the light amount of the reflected light. Tracking area 3
One pair of tracking marks 33a, 33b
From the signal reproduced from, the displacement of the light spot position from the track center line 38 in the radial direction is detected, and thereby tracking control is performed. The signal reproduced from the sync signal mark 34 is used for recording and reproducing the information signal in the data area 32.

If the recording layer is made of a photochromic material having a characteristic that it reacts when irradiated with high-power light and does not react when irradiated with low-power light, a tracking mark and a sync signal mark are reproduced by reproduction. , The information signal mark is never erased. Further, in the present embodiment, the tracking area and the data area are separately provided even though the recording layer is one layer. Therefore, the tracking area can be irradiated with a high power laser during recording. Therefore, the tracking mark and the sync signal mark are not erased.

Further, the recording layer has different optical characteristics due to the irradiation of the light of the first wavelength and the irradiation of the light of the second wavelength.
If it is composed of a material that reversibly changes between two states and the light of the first wavelength and the light of the second wavelength are used for recording and erasing information signals, not only a write-once type optical recording medium but also A rewritable optical recording medium can also be realized.

In the second step (transfer) of each embodiment of the method for manufacturing an optical recording medium described above, the intensity of light of a specific wavelength generated by the high pressure mercury lamp is 500 mW / on the recording layer of the optical recording medium. cm ² , the energy required for the isomerization reaction of the photochromic dye material constituting the recording layer is 200
With mJ / cm ² , the light irradiation time is 0.4 seconds per one transfer process. When an excimer laser that is pulse-lighted is used as the light source, the light energy density per pulse is 5 mJ / cm ² , and the pulse frequency is 5
When the frequency is 00 Hz, one transfer process takes 0.08 seconds.
Furthermore, by simultaneously transferring data to a plurality of optical recording media using a mask on which a plurality of patterns are formed, it is possible to further increase the production capacity.

In the above embodiment, light is uniformly applied to the entire surface of the pattern on the mask and the pattern is collectively transferred and formed on the recording layer. However, light is partially applied to the pattern on the mask. The entire pattern may be transferred to the recording layer by scanning the entire surface of the recording layer while irradiating. However, in order to reduce the required time, it is desirable to transfer the entire pattern at once.

In the second step (transfer) of the above embodiment, the mask is held with a sufficient space between it and the substrate, and the image of the pattern formed on the mask is projected onto the recording layer in a reduced size. Then, the tracking marks, sync signal marks, tracking guides, data recording tracks, etc. formed on the mask on the recording layer are reduced and transferred.
An image of the same size as the pattern may be projected onto the recording layer without being reduced, and transferred at the same size as the pattern.

Further, the mask and the substrate are brought into close contact with each other, an image of the same size as the pattern formed on the mask is projected on the recording layer, and a tracking mark and a synchronization signal having the same size as the pattern formed on the mask are formed. Marks, tracking guides, etc. may be transferred.

Further, the mask is placed close to the substrate with a minute interval, and an image of approximately the same size as the pattern formed on the mask is projected onto the recording layer, and the size of the pattern formed on the mask is approximately the same. The tracking marks, synchronization signal marks, tracking guides, data recording tracks, etc. may be transferred.

However, it is difficult to expose a large area at a time when the mask pattern is projected in a reduced size, but since a high resolution is obtained, a small-sized and large-capacity optical recording medium is manufactured. However, when transferring the mask pattern at the same size, it is possible to expose a large area at once, and it is possible to manufacture a relatively large optical recording medium and It is suitable for a case where a plurality of patterns are formed on the substrate and are simultaneously exposed to transfer to a plurality of optical recording media.

Further, when the mask and the substrate are not brought into close contact with each other and are held with a space therebetween, it is desirable that the mask is not deteriorated even by repeated use and can be used semipermanently.

The order of the steps of the method for manufacturing an optical recording medium according to the present invention is not necessarily limited to the order shown in the above-mentioned embodiments. For example, the cutting step may be performed before the transfer step.

A high pressure mercury lamp was used as a light source in the second step (transfer) of each of the above-mentioned embodiments, but other than this, a KrF excimer laser (wavelength 248 nm) or A
An rF excimer laser (wavelength 193 nm) may be used as a light source. Generally, the shorter the wavelength of the light source is, the higher the resolution of transfer is. When the light having the wavelength of 365 nm is used, the mark having the length and the width of 0.3 μm is obtained, and the light having the wavelength of 248 nm is used. A 0.2 μm mark can be formed by transfer.

In each of the above embodiments, the first wavelength, that is, the wavelength of the light used for transfer in the manufacture of the optical recording medium is shorter than 500 nm, and the second wavelength, that is, the information signal to the optical recording medium. The wavelength of light used for recording is 50
Although the wavelength is set to 0 to 800 nm, the wavelength of light in the present invention is not necessarily limited to this. For example, the wavelength of light used for transfer and the wavelength of light used for recording or reproducing an information signal in the manufacture of an optical recording medium may be the same, or the first wavelength may be longer than the second wavelength. Further, the wavelength of light used for recording the information signal and the wavelength of light used for reproduction can be made different.

In the embodiment, light is irradiated to change the light absorption rate of the recording layer to transfer and form a tracking mark, a tracking mark, a synchronization signal mark, a data recording track, or an information signal mark. However, the light transmittance or reflectance of the recording layer may be changed.

In the embodiments described above, the optical recording medium is an optical disk, but the present invention is not limited to this, and is also applicable to optical recording media such as optical cards and optical tapes.

[0101]

Since the recording medium of the present invention is formed with the tracking guide, the tracking mark, the synchronization signal mark and the like without changing the shape of the surface of the recording layer, it is required to be manufactured. The time can be greatly shortened compared to the manufacturing method such as the conventional injection molding method in which tracking guides, pits of synchronization signals are formed by changing the shape of the substrate, which enables mass production of optical recording media. And is effective in reducing the manufacturing cost. In particular, by irradiating the light of the first wavelength through the mask to collectively form the pattern on the recording layer, it is possible to greatly improve the production efficiency. Furthermore, it is possible to transfer to a plurality of optical recording media at the same time by using a mask having a plurality of patterns formed thereon, and it is possible to further increase the production capacity.

Also, using a substrate made of a long sheet,
If the recording medium is continuously manufactured through each process in the process of transferring the substrate, the time required in the process of coating and forming the recording layer is shortened as compared with the conventional spin coating, and the use efficiency of the material is improved. As a result, the mass production with further improved manufacturing efficiency as compared with the conventional manufacturing method becomes possible, and it is effective in reducing the manufacturing cost.

Unlike the conventional manufacturing method, the optical characteristics of a specific wavelength are partially changed without changing the shape of the surface of the recording layer. Since marks and the like are transferred and formed, the transfer resolution can be increased, and signals can be recorded at higher recording densities (track density and linear recording density). As a result, a large capacity recording medium can be realized. Especially, the wavelength of light used for transfer is 50
This effect is large when the length is shorter than 0 nm.

Further, when the mask is not brought into close contact with the recording medium in the transfer step, the mask can be used semipermanently and repeatedly, so that the recording medium can be mass-produced with a small amount of the mask.

When the recording layer of the present invention is composed of two layers, the photochromic material forming the first recording layer is
Assuming that no change in light transmittance, reflectance, or absorptance occurs even when light of a second wavelength (for example, 500 to 800 nm) is irradiated, light of the second wavelength (500 to 800 nm) is used for reproduction. Even if it is used, the tracking mark and the sync signal mark are not erased.

The second recording layer also has a wavelength of 500 to 80.
The information signal mark is not erased by reproduction by using a photochromic material having a characteristic that it reacts when irradiated with high power light at 0 nm and does not react when irradiated with low power light.

In addition, the second recording layer is formed with the second wavelength (500
(-800 nm) and a third wavelength different from the second wavelength (e.g. shorter than 500 nm), a material that reversibly changes between two states having different optical properties. A second wavelength light and a third
If the light of the wavelength of is used for recording and erasing the information signal,
It is possible to realize not only a write-once type optical recording medium but also a rewritable type optical recording medium.

Further, in the different invention of the present application in which the recording layer is composed of one layer, it is preferable that the recording layer is made of a photochromic material having a characteristic that it reacts when irradiated with high power light and does not react when irradiated with low power light. , The tracking mark synchronization signal mark and the information signal mark are not erased by the reproduction. Further, since the tracking area and the data area are separated, the tracking area is not irradiated with a high power laser even during recording, so that the tracking mark and the synchronization signal mark are not erased. .

Further, the recording layer has different optical characteristics due to the irradiation of the light of the first wavelength and the irradiation of the light of the second wavelength.
If it is composed of a material that reversibly changes between two states and the light of the first wavelength and the light of the second wavelength are used for recording and erasing information signals, not only a write-once type optical recording medium but also A rewritable optical recording medium can also be realized.

[Brief description of drawings]

FIG. 1 is an example of a manufacturing process of an optical recording medium of the present invention.

FIG. 2 is a diagram illustrating a mask pattern transfer process.

FIG. 3 is a diagram showing a configuration of a mask.

FIG. 4 is a partial enlarged view of a mask according to an embodiment of the present invention.

FIG. 5 is a diagram showing an optical recording medium which is in the process of being manufactured after the transfer step in one embodiment of the present invention.

FIG. 6 is a diagram showing an optical recording medium after formation of a second recording layer in one example of the present invention.

FIG. 7 is a diagram showing an optical recording medium after recording an information signal in one example of the present invention.

FIG. 8 is a partial enlarged view of a mask according to an embodiment of the present invention.

FIG. 9 is a diagram showing an optical recording medium in the process of being manufactured after the transfer step in one example of the present invention.

FIG. 10 is a diagram showing an optical recording medium after formation of a second recording layer in one example of the present invention.

FIG. 11 is a diagram showing an optical recording medium after recording an information signal in one example of the present invention.

FIG. 12 is a diagram showing a manufacturing process of the optical recording medium in one example of the present invention.

FIG. 13 is a partially enlarged view of the mask according to the embodiment of the present invention.

FIG. 14 is a diagram showing an optical recording medium after a transfer process in one example of the present invention.

FIG. 15 is a diagram showing an optical recording medium after recording an information signal in one example of the present invention.

FIG. 16 is a partially enlarged view of the mask according to the embodiment of the present invention.

FIG. 17 is a diagram showing an optical recording medium after a transfer process according to an example of the present invention.

FIG. 18 is a diagram showing an optical recording medium after recording an information signal in one example of the present invention.

FIG. 19 is a diagram showing a schematic configuration of a recording / reproducing apparatus.

FIG. 20 is a diagram showing a manufacturing process of a conventional optical disc.

[Explanation of symbols]

 10 Substrate 11 First Recording Layer 12 Recording Layer 13 Second Recording Layer 14 Reflective Film 15 Protective Film 20 High Pressure Mercury Lamp 21 Condenser Lens 22 Mask 23 Reduction Projection Lens 24 Stage 31 Tracking Area 32 Data Area 33a, 33b Tracking Mark 34 sync signal mark 35 tracking guide 36 data recording track 37 information signal mark 38 track center line

Claims (10)

[Claims] 1. A material formed of a material whose light transmittance, reflectance, or absorptance is changed by irradiation with light of a first wavelength, and the light transmittance or reflection of light by irradiation of the first light. rate,
A first recording layer having a tracking guide or a tracking mark in which one of the absorptances is different from the surroundings, and the light transmittance, the reflectance, and the absorptance of the light by irradiation with the light of the second wavelength. A second recording layer, which is formed of a material in which any of them is changed and is capable of recording an information signal by irradiation with the light having the second wavelength, is provided by being laminated on a substrate. recoding media. 2. The first recording layer is made of a material whose transmittance, reflectance and absorptance of light do not change even when irradiated with the light of the second wavelength.
An optical recording medium according to claim 1. 3. The second recording layer has a light transmittance, a reflectance, or an absorptance that is changed by irradiation with light having a high power at the second wavelength. The material is made of a material that does not change any of light transmittance, reflectance, and absorptance when irradiated with low-power light.
Or the optical recording medium according to 2. 4. The second recording layer has any of a light transmittance, a reflectance, and an absorptance when irradiated with light having the second wavelength and light having a third wavelength different from the second wavelength. The optical recording medium according to claim 2 or 3, wherein the optical recording medium is made of a material that reversibly changes between two different states. 5. A step of forming, on a substrate, a first recording layer made of a material whose light transmittance, reflectance or absorptance is changed by irradiation with light having a first wavelength, and Of the light having the wavelength of 10 nm to form the tracking guide or the tracking mark in the first recording layer, and the irradiation of the light having the second wavelength causes any of the light transmittance, the reflectance, and the absorptance. And a step of forming a second recording layer made of a material whose shape changes. 6. A step of forming, on a substrate, a first recording layer made of a material whose light transmittance, reflectance, or absorptance changes by irradiation with light having a first wavelength, and the step of forming the first recording layer. Irradiating the first layer formed by the method with light having a first wavelength to form a tracking guide or a tracking mark in the first recording layer, and a tracking guide or a tracking mark by the step. On the first recording layer on which the mark is formed, a second recording layer made of a material whose light transmittance, reflectance or absorptance is changed by irradiation with light of the second wavelength is laminated. A method for manufacturing an optical recording medium, which comprises a step of forming the optical recording medium. 7. A material that changes between two states having different light transmittances, reflectances, or absorptivities due to irradiation with light having a first wavelength and irradiation with light having a second wavelength. , A tracking region having a tracking mark in which one of the transmittance, reflectance, and absorption of light by irradiation with the light of the first or second wavelength is different from the surrounding area, and the light of the first wavelength Alternatively, the optical recording medium is characterized in that a recording layer having a data area having a data recording track capable of recording an information signal by irradiation with the light of the second wavelength is provided on the substrate. 8. The recording layer has a light transmissivity depending on irradiation with light of high power at the first wavelength or the second wavelength,
It is made of a material whose reflectance or absorptance is changed and whose transmittance, reflectance or absorptance of light is not changed by the irradiation of light of low power at the first wavelength or the second wavelength. The optical recording medium according to claim 7, wherein: 9. The recording layer is reversible between two states having different light transmittance, reflectance, or absorptivity upon irradiation with the light having the first wavelength and the light having the second wavelength. 9. The optical recording medium according to claim 7, which is made of a material that changes to. 10. A method of manufacturing an optical recording medium provided with a recording layer in which a tracking area and a data area in which an information signal can be recorded are formed separately, wherein a substrate is irradiated with light of a first wavelength. And a step of forming a recording layer made of a material that changes between two states having different light transmittances, reflectances, or absorptivities upon irradiation with light of the second wavelength, and the recording layer, By irradiating the light having the first wavelength or the light having the second wavelength, a tracking mark having a light transmittance, a reflectance, or an absorptance different from that of the surrounding is formed in the tracking region, and at the same time, the data region And a step of bringing the data recording track of 1. into a state in which an information signal can be recorded.