JPH0287343A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To decrease the block error rate of pits by interposing a bond layer which imparts inter-layer bondability between a light reflection layer and other layer which sandwiches this layer. CONSTITUTION:The bond layer 6 which imparts inter-layer bondability is interposed between the light reflection layer 3 and the other layer which sandwiches this layer. Laser light is, therefore, converged and the inter-layer peeling takes place only in the extremely narrow range where the energy is concentrated at the time of irradiating the light absorption layer 2 with the laser light 7 to form the pit 5. The pits 5 which are distinct as compared with the case in which the bond layer 6 is not interposed are formed in this way. The resolving power of the pits 5 is thus enhanced and the block error rate is lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical information recording medium that is irradiated with a laser beam and reproduces recorded data using the reflected light.

[Prior Art] An optical information recording medium that can record data by irradiation with laser light is TeX BiX MnW QB.
By irradiating laser light through a recording layer consisting of a pigment layer such as S, cyanine, merocyanine, phthalocyanine, etc.
Data is recorded by forming pits by deforming, sublimating, evaporating, or denaturing the recording layer. When reproducing the recorded data, a laser beam with a lower power than that during recording is emitted from the substrate I side with n, r < Qj L, .
Due to the difference in reflected light between the pit and other parts,
Read the signal.

In order to solve the various problems with such conventional recordable optical information recording media, the inventors of the present invention have developed a cyanide film on the transparent substrate 1 either directly or through another layer, as shown in the drawings. A light absorption layer 2 made of a dye or the like absorbs laser light and generates heat, generating gas and increasing pressure, and a light reflection layer 3 made of a gold fi film is formed thereon directly or via another layer. devised a recordable optical information recording medium. According to this optical information recording medium, the so-called typical RO
A recordable optical information recording medium that satisfies the CD format specified for compact discs (CDs), which are M-type optical information recording media, in terms of reflectance of laser light, degree of modulation of data reproduction signals, etc. is obtained.

A typical example of the formation process of bit 6 in this optical information recording medium is shown in FIG. That is, as shown in the figure, when the laser beam 7 from the optical pickup 8 is focused on the light absorption layer 2, the light absorption layer absorbs the laser beam 7, generates heat, generates gas, and increases the pressure. do. For this reason, it deforms itself while deforming a relatively soft adjacent layer, for example, the transparent substrate 1, and forms a recessed bit 5 on the surface of the transparent substrate 1.

In this way, in the above-mentioned optical information recording medium, concave bits similar to those formed on a CD by means such as a press are formed on the surface of the transparent substrate l, and behind the concave bits, the light reflecting the laser beam is formed. Since the reflective layer 3 is thin, the reflectance of the laser beam is high,
In addition, a reproduced signal with a high degree of modulation can be obtained.

[Problems to be Solved by the Invention] In the above-mentioned optical information recording medium, a problem in forming bits is the binding property between the light reflective layer 3 and other layers in contact with it. That is, as shown in FIG. 4(a), when a bit is formed, gas is generated in the light absorption layer 2, and when the pressure increases, the light reflection layer 3, which has the weakest binding force,
and the light absorption layer 2 are separated by ψJ, gas generated from the light absorption layer 2 accumulates there, and a void 10 is formed. When this gap is formed locally in the narrow area where bit 5 is formed, the laser beam incident for reproduction will be scattered and absorbed there, causing bit 6 and other parts to This has the advantage that there is a large difference in the amount of reflected laser light, and the C/N ratio of the reproduced signal can be increased.

However, if the void IO caused by the peeling is formed over a wide range as shown by the broken line in FIG. This delamination, which has a high block error rate of so-called bit 5, occurs not only when it occurs on the side where the laser beam is incident on the light reflection layer 3, but also when it occurs on the back side thereof, the same problem occurs.

That is, if delamination occurs on the back side of the light reflective layer 3 during the formation of the bit 6, if the binding force between the light reflective layer 3 and the layer in contact with the back side is weak, the delamination will occur over a wide range. It happens over a period of time. In this case, the surface disturbance of the light reflecting layer 3 is spread over a wide range, so the amount of reflected light is reduced, and the bit 5
The resolution of the bit 5 decreases, and a so-called bit 5 block error rate occurs frequently.

It has been found that such a problem of interlayer peeling occurring over a wide range often occurs when the adhesiveness between the light reflective layer 3 and other layers in contact with it is poor. The light reflecting layer 3 is formed by depositing a gold B film on the surface of the disk by sputtering or vacuum deposition, so that
Bonding properties with adjacent layers tend to deteriorate,
The problem is the increase in the block error rate.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the problems with the optical information recording medium.

[Means for Solving the Problems] In other words, the gist of the means adopted in the present invention to achieve the above object is to use a laser beam provided directly or via another layer on the transparent substrate l. Absorbing light absorption layer 2
and a light reflecting layer 3 that reflects laser light and is provided directly on the light absorbing layer 2 or via another layer, the light reflecting layer 3 and another layer sandwiching the light reflecting layer 3. A binding layer 6 that provides interlayer binding between the two
This is an optical information recording medium characterized in that a.

[Function] In this optical information recording medium, the binding B6 that provides binding properties between these layers is interposed between the light reflective layer 3 and other layers in contact with it, so the fourth As shown in the figure, when the light absorption layer 2 is irradiated with a laser beam 7 to form a bit 5, the laser beam 7 is converged and delamination occurs only in a very narrow range where the energy is concentrated. Therefore, compared to the case where the binding layer 6 is not interposed, clear pits 5 can be formed, the resolution of the pits 50 can be increased, and the block error rate can be reduced.

[Embodiments] Next, embodiments of the present invention will be described in detail with reference to the drawings.

Examples of the schematic structure of the optical information recording medium according to the present invention are shown in FIGS. 1 to 3. In the figure, 1 is a light-transmitting substrate, and 2 is a light-absorbing layer formed thereon, which absorbs the irradiated laser light and generates heat, causing melting, evaporation, sublimation, etc.
This layer deforms or denatures and has the function of forming pits on the surface of the light-transmitting substrate l.

Reference numeral 3 indicates a light reflecting layer formed thereon to reflect laser light, and reference numeral 4 indicates a protective layer provided on the outside thereof.

In the present invention, as described above, the binding layer 6 that provides binding properties for living rooms is interposed between the light reflective layer 3 and at least one of the other layers sandwiching it.

This binding layer 6 is made of a material that can provide a stronger binding force to the light reflecting layer 3 than the other layers, since it is intended to improve the binding between the light reflecting layer 3 and other layers in contact with it. It is necessary to select and use.

Note that FIG. 2 shows the state before recording with laser light, and
The figure schematically shows the state after recording, that is, the state in which the surface of the substrate 1 is partially deformed and pits 5 are formed due to local thermal deformation of the light absorption layer 2 during laser beam irradiation. .

Furthermore, FIG. 4(a) shows that when the binding layer 6 is provided on the incident side of the laser beam 7 from the optical pickup 8 of the light reflection layer 3,
FIG. 6B shows a case where a binding layer 6 is provided on the back side. Of course, it is also possible to provide the binding layer 6 on both sides of the light reflecting layer 3.

A specific example of this optical information recording medium will be described below.

(Example 1) A translucent substrate 1 was formed by injection molding and had a diameter of 46 to 117 mmφ, a width of 0°8 μm1 and a depth of O.
-08ams pitch 1. Thickness L for growing 6μm spiral pre-groove 8 2mmz Outer diameter 1
A polycarbonate M disk (manufactured by Teijin Kasei ■, trade name: Panlite) having a diameter of 20 mm and an inner diameter of 15 mm was used.

0.65 g of 1,1' dibutyl3. 3. 3'3'
Te!・Ramethyl 4. 5. 4', 5' Dibenzoindodicarbocyanine perchlorate (manufactured by Japan Photosensitive Color Research Institute, product number NK3219) was dissolved in 10 cc of diacetone alcohol solvent, and this was applied to the surface of the above substrate 1 by a spin code method. , a light absorption layer 2 having a thickness of 130 nm was formed.

Next, a reflective layer 3 was formed by depositing an Ag film with a thickness of 50 nm on the entire surface of the disk with a diameter of 45 to 118 mm by sputtering. Furthermore, this reflective layer 3
On top of this, polybutadiene resin is applied as a binding layer 6 to a thickness of 20 mm.
It is formed using nm spin code, and then silicon acrylic (
A 2 .mu.m thick spin cord was used to form the resin. On top of this, an ultraviolet curable resin was spin coated and cured by irradiating ultraviolet rays to form a protective layer 4 with a thickness of 10 .mu.m.

The thus obtained optical disc was irradiated with a semiconductor laser having a wavelength of 780 nm at a line iMt, 2 m/sect, and a recording power of 6.0 mW to record an EFM signal. This optical disc is then inserted into a commercially available CD player (Aur
ex XR-V73, reproduction light wavelength λ = 780 nm)
When reproduced, the eye pattern of the reproduced signal was clear and the block error rate was 2.5×10 −3 .

(Example 2) In the above Example 1, a polycarbonate disk (manufactured by Mitsubishi Gas Chemical (llil, product name:
In addition, an Au film was formed as the light-reflecting layer 3, and a 20 nm thick film was used as a binding layer 6 between the light-reflecting layer 3 and the protective layer 4 made of ultraviolet curing resin. An optical disc was manufactured in the same manner as in Example 1, except that the saturated polyester resin layer was formed by spin cording, and a 2 μm thick epoxy resin layer was formed thereon by spin cording.

EFM signals were recorded on the thus obtained optical disc in the same manner as in Example 1, and then this optical disc was
When played on a commercially available CD player, the eye pattern of the playback signal was clear and the block error rate was 2.
．． It was 8X10-3.

(Example 3) In Example 1 above, a polystyrene disc was used as the light-transmitting substrate 1, and the pregroove on this disc was wobbled at 22.1 kHz with an amplitude of 30 m, and the light absorption layer The film thickness of layer 2 was 90 nm, and an acrylic resin layer with a thickness of 40 mm was formed between the light absorption layer 2 and the light reflection layer 3 by a spin cord method, and a binding layer 6 was formed on this layer.
As a result, an epoxy resin layer with a thickness of 10 m was formed using a spin cord, and an Au film was formed thereon as a light reflection layer 3, and a protective layer 4 was formed directly on this light reflection layer 3. Except for this, an optical disc was manufactured in the same manner as in Example 1 above.

EFM signals were recorded on the thus obtained optical disc in the same manner as in Example 1, and then this optical disc was
When reproduced with a commercially available C and D player, the eye pattern of the reproduced signal was clear and the block error rate was 3.5XlO''2.

(Example 4) In Example 1 above, a polystyrene disk was used as the light-transmitting substrate 1, and polyamide resin was spun on the light-reflecting layer 3 to a thickness of 20 mm as a binding WJ6. An optical disk was manufactured in the same manner as in Example 1, except that a polyester resin was formed using a spin cord to a thickness of 2 μm, and a protective layer 4 was formed thereon. .

EFM signals were recorded on the thus obtained optical disc in the same manner as in Example 1, and then this optical disc was
When played on a commercially available CD player, the eye pattern of the playback signal was clear and the block error rate was 3.
．． It was 0x10-3.

(Example 5) As the light-transmitting substrate 1, a polyolefin disk (manufactured by Mitsui Petrochemical Co., Ltd.) having a pregroove similar to that of Example 1 on the surface was used, and 0.65 g of 111' dibutyl 3. 3.3'3'Tetramethyl 5.5' diethoxyindodicarbocyanine perchlorate was dissolved in 10 cc of diacetone alcohol solvent and applied by a spin code method to form a light absorption layer 2 with a film thickness of 90 mm. did.

Next, on this light absorption layer 2, acrylic resin is applied to a thickness of 40 mm.
After forming the bonding layer 6 using a spin cord so as to have a thickness of 10 mm, vinyl chloride was formed thereon as a bonding layer 6 using a spin cord so as to have a thickness of 10 mm. And the diameter above this is 45
An Au film with a thickness of 50 nm was formed on the entire surface of a region of 118 mmφ by sputtering to form a light reflecting layer 3. Further, an ultraviolet curable resin was spin-coded on the light reflecting layer 3, and was cured by irradiating ultraviolet rays to form a protective layer 4 having a thickness of 10 μm.

EFM signals were recorded on the thus obtained optical disc in the same manner as in Example 1, and then this optical disc was
When played on a commercially available CD player, the eye pattern of the playback signal was clear and the block error rate was 3.
．． It was 7X10-3.

(Example 6) In the above Example 5, an epoxy disk was used as the transparent substrate 1, a light reflection layer 3 made of an AI film was directly formed on the light absorption layer 2, and the light reflection layer 3 Tie layer 6 on top of
An optical disc was manufactured in the same manner as in Example 5 above, except that a urethane resin was formed with a spin cord to a thickness of 20 mm, and then a protective layer 4 was formed on the resulting optical disc. E in the same manner as in Example 1 above.
When an FM signal was recorded and the optical disc was then played back on a commercially available CD player, the eye pattern of the playback signal was clear and the block error rate was 3.2X.
It was 10-3.

(Example 7) In the above Example 5, a polymethyl methacrylate disk (manufactured by Mitsubishi Rayon ■, trade name: Niaclipet) was used as the light-transmitting substrate l, and a light-reflecting layer 3 was placed on the light-absorbing layer 2.
A 1M isocyanate resin was formed with a spin cord to a thickness of 20 nm as a binding layer 6 on the light reflecting layer 3, and a fluororesin was further formed on this to a thickness of 2 nm.
A protective layer 4 is formed on the spin code so that the thickness of
An optical disc was manufactured in the same manner as in Example 5 above, except that the following was formed.

EFM signals were recorded on the thus obtained optical disc in the same manner as in Example 1, and then this optical disc was
When played on a commercially available CD player, the eye pattern of the playback signal was clear and the block error rate was 3.
．． 4X] 0-3.

(Example 8) In the above Example 5, a polymethyl methacrylate circle or plate (manufactured by Kyowa Gas Kagaku ■, trade name: Parapet) was used as the light-transmitting substrate I, and the film thickness was 40 mm on the light absorption layer 2.
A light reflection layer 3 made of an 8=2 alloy thin film of Au and Sb was formed on a SiO2 layer of 100 nm thick by sputtering, and a polyisoprene resin was formed as a binding layer 6 on the light reflection layer 3. An optical disc was manufactured in the same manner as in Example 5, except that the protective layer 4 was formed on the 20-nm-thick film using a spin cord.

EFM signals were recorded on the thus obtained optical disc in the same manner as in Example 1, and then this optical disc was
When played on a commercially available CD player, the eye pattern of the playback signal was clear and the block error rate was 2.
．． It was 9XlO-3.

(Example 9) In the above Example 5, a polycarbonate disk was used as the transparent substrate I, a light reflection layer 3 was formed directly on the light absorption layer 2, and a light reflection layer 3 was formed on the light reflection layer 3. An optical disc was produced in the same manner as in Example 5, except that the protective layer 4 was formed by laminating an ultraviolet curable resin with a spin cord to a thickness of 1100 nm and a polycarbonate sheet as the adhesive layer 6. did.

EFM signals were recorded on the thus obtained optical disc in the same manner as in Example 1, and then this optical disc was
When played on a commercially available CD player, the eye pattern of the playback signal was clear and the block error rate was 3.
．． It was 3XIQ-3.

(Example 10) A polycarbonate disk similar to that of Example 1 was used as the light-transmitting substrate 1, and the surface thereof was coated with 0.65-111' dibutyl 3.3.3'3' tetramethyl 5.5' jetoxy. Indocicabonanine barchlorate was dissolved in 10 cc of diacetone alcohol solvent and applied by a spin code method to form a light absorption layer 2 with a thickness of 130 nm.

On the other hand, on the surface of an A1 disk with a thickness of 100 μm as the protective layer 4, a disk plated with Au with a thickness of 1'750 nm as the light reflecting layer 3 was placed.

Then, on the light absorption layer 2 of the former disk, an epoxy resin with a thickness of 1100 nm was spin-coded as a binding layer 6, and after this binding layer 6 was applied, the Au plating of the latter disk was applied. The two discs were glued together with their sides aligned to produce an optical disc.

EFM signals were recorded on the thus obtained optical disc in the same manner as in Example 1, and then this optical disc was
When nT was played using a commercially available CD player, the eye pattern of the playback signal was clear and the block error rate was 3.5XI0I.

(Comparative Example) In Example 1 above, silicon acrylic resin and protective layer 4 were provided directly on light reflective layer 3 without spin-coding polybutadiene resin as binding layer 6 on light reflective layer 3. Except for this, an optical disc was manufactured in the same manner as in Example 1 above.

EFM signals were recorded on the thus obtained optical disc in the same manner as in Example 1, and then this optical disc was
When played on a commercially available CD player, the eye pattern of the playback signal was clear and the block error rate was 1.
．． It was 5X10-2.

[Effects of the Invention] As explained above, according to the optical information recording medium of the present invention,
Laser light! When forming concave bits similar to CDs on the surface of the substrate by flash firing, locally clear bits can be formed, making it possible to increase bit resolution and record data with a low block error rate. 4. Drawing (Dill Su3Q)
A schematic half-sectional perspective view showing an example of the structure of an optical information recording medium,
Figure 2 is an enlarged view of section A in Figure 1 before optical recording, and Figure 3 is
FIG. 1 is an enlarged view of part A after optical recording, and FIG. 4 is a schematic vertical cross-sectional view of a main part showing an example of the form of a bit formed in the same embodiment.

Claims (1)

[Claims] A light absorption layer 2 that absorbs laser light, which is provided directly on the transparent substrate 1 or through another layer; and a laser light absorption layer 2 that is provided on the light absorption layer 2, either directly or through another layer. In an optical information recording medium having a light reflective layer 3 that reflects light, between the light reflective layer 3 and at least one of the other layers sandwiching the light reflective layer 3,
An optical information recording medium characterized in that a binding layer 6 is interposed to provide binding properties between layers.