JP2003099981A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium whose friction characteristics(friction force and/or friction coefficiency) of the surface of the optical recording medium, especially the surface of a light transmission layer or a hard coat layer is lowered. SOLUTION: The optical recording medium is provided with a substrate 11, a recording layer 13 set up on the substrate 11, and a hard coat layer 15 set up on the recording layer 13, and recording/reproducing of data is performed by irradiating a laser beam via the hard coat layer 15. The friction coefficient measured by rotating the optical recording medium at the rotating speed of 50 to 300 rpm, and impressing a planar load of 5 to 50 g/cm<2> to the surface of the hard coat layer 15 via a self adhesion type bonded textile of continuous fiber whose major component is cellulose is equal or less than 1.5. Accordingly, the getting of a scratch on the surface of a translucent base substance which is a light entrance plane is effectively prevented.

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, and more particularly to an optical recording medium in which the occurrence of scratches on the light incident surface is effectively prevented.

[0002]

2. Description of the Related Art In recent years, optical recording media represented by CDs and DVDs have been widely used as recording media for recording a large amount of digital data. Generally, a read-only optical recording medium has a light-transmitting layer (light-transmitting substrate), a reflective layer, and a protective layer laminated in this order from the light-incident surface side. Each layer is laminated in the order of a light transmitting layer (light transmitting substrate), a recording layer, a reflecting layer, and a protective layer. In a read-only optical recording medium, the reflective layer serves as an information recording layer, and in a writable optical recording medium, the recording layer serves as an information recording layer. In any type of optical recording medium, when reading data, a reproducing laser is irradiated from the light transmitting layer side and the reflected light is detected. When writing data on a writable optical recording medium, a recording laser is irradiated from the light transmitting layer side, and the chemical state or physical state of the recording layer is recorded by the thermal energy and / or the light energy. It can be changed based on the power data.

Here, the laser applied to the optical recording medium is focused by an optical system so that a beam spot having a predetermined diameter is formed on the reflection layer or the recording layer. Therefore, if a flaw is present on the surface of the light transmitting layer, the beam spot may not be formed correctly, and a read error or a write error may occur. As a method for preventing the occurrence of such scratches, conventionally known is a method of providing a hard coat layer having high hardness on the surface of the light transmitting layer.

[0004]

By the way, in recent years, the numerical aperture (NA) of the objective lens for focusing the recording / reproducing laser beam is increased to 0.7 or more, for example, to about 0.85, and recording / reproducing is performed. The wavelength λ of the reproduction laser light is 400
Attempts have been made to reduce the focused spot diameter of laser light by shortening it to about nm, thereby recording a large amount of digital data. When the NA is increased in this way, the tolerance of warpage or tilt of the optical recording medium, that is, the tilt margin becomes small. Therefore, in order to secure a sufficient tilt margin, the thickness of the light transmitting layer (light transmitting substrate) is required. Need to be thin. For example, NA = 0.85, λ = 4
When it is set to about 00 nm, it is required to reduce the thickness of the light transmission layer to about 100 μm in order to secure a sufficient tilt margin.

Further, if the NA is increased, the working distance (working distance) between the objective lens and the surface of the optical recording medium becomes small. For example, when NA is set to about 0.85, the working distance becomes It is about 100 μm, which is remarkably narrower than the conventional one.

However, when the working distance becomes extremely narrow, the surface of the optical recording medium is highly likely to come into contact with the objective lens or the support for supporting the objective lens during the rotation of the optical recording medium. If such contact occurs during the rotation of the optical recording medium, the surface of the light transmitting layer of the optical recording medium may be fatally damaged. The occurrence of scratches due to such contact can be suppressed to some extent by providing the above-mentioned hard coat layer. However, when the light transmission layer is thinned to about 100 μm, the recording / reproducing laser light on the surface of the light transmission layer is reduced. Since the condensing diameter is also significantly reduced, even a scratch or stain of a size that does not cause a reading error or a writing error in the conventional optical recording medium easily becomes a reading error or a writing error. Therefore, merely increasing the hardness of the hard coat layer is not sufficient to reduce scratches caused by contact during rotation.

The present inventors not only increase the hardness of the hard coat layer but also increase the friction coefficient of the hard coat layer surface in order to effectively reduce scratches on the surface of the optical recording medium caused by contact during rotation. It was concluded that reducing it is effective.

Therefore, an object of the present invention is to provide an optical recording medium in which the friction characteristics (friction force and / or friction coefficient) of the surface of the optical recording medium, particularly the surface of the light transmitting layer or the hard coat layer are reduced. .

Another object of the present invention is an optical recording medium of the type which records / reproduces data without physical contact, wherein the friction characteristic of the light incident surface is reduced. Is to provide.

[0010]

As described above, the present invention is
In order to effectively reduce scratches on the surface of the optical recording medium caused by contact with the objective lens and the support that supports the optical recording medium during rotation, the friction coefficient of the surface of the optical recording medium should be reduced and Based on the idea that it is effective to mitigate the damage of 1., the present invention provides an optical recording medium in which the friction coefficient is reduced to a predetermined value or less.

An object of the present invention is to provide a substrate, an information recording layer provided on the substrate, and a translucent substrate provided on the information recording layer, with the translucent substrate interposed therebetween. An optical recording medium in which data is recorded / reproduced by irradiating the information recording layer with a laser beam, wherein the surface of the transparent substrate is rotated while rotating the optical recording medium at a rotation speed of 50 to 3000 rpm. 5 to 50 g / cm ₂ through a self-adhesive long-fiber non-woven fabric containing cellulose as a main component
The coefficient of friction measured by applying a planar load is 1.5
It is achieved by an optical recording medium characterized by the following.

According to the present invention, since the friction coefficient of the surface of the light-transmissive substrate is suppressed to 1.5 or less, the generation of scratches on the surface of the light-transmissive substrate, which is the light incident surface, is effectively generated. To be prevented.

In a preferred embodiment of the present invention, the friction coefficient is 100 to 1500 revolutions of the optical recording medium.
This is the value when set to rpm.

In a preferred embodiment of the present invention, the coefficient of friction of the surface of the translucent substrate is 1.0 or less.

According to a further preferred aspect of the present invention, since the friction coefficient of the surface of the light-transmitting substrate is suppressed to 1.0 or less, the surface of the light-transmitting substrate, which is the light incident surface, is not damaged. Outbreak is prevented more effectively.

In a further preferred aspect of the present invention, the coefficient of friction of the surface of the translucent substrate is 0.8 or less.

According to a further preferred aspect of the present invention, since the friction coefficient of the surface of the transparent substrate is suppressed to 0.8 or less, the surface of the transparent substrate, which is the light incident surface, is not scratched. Outbreaks are prevented even more effectively.

[0018] In a further preferred aspect of the present invention, the translucent substrate comprises a light transmissive layer and a hard coat layer provided on the surface thereof.

In a further preferred aspect of the present invention, the thickness of the light transmitting layer is 5 to 300 μm.

In a further preferred aspect of the present invention, the hard coat layer contains a lubricant.

[0021] In a further preferred aspect of the present invention, the lubricant is a silicone lubricant, a fluorine lubricant or a fatty acid ester lubricant.

In a further preferred aspect of the present invention, the content of the lubricant is 0.1 to 5.0% by mass.

In a further preferred aspect of the present invention, the coefficient of friction is such that the cumulative number of revolutions of the optical recording medium is 1.
It is a value in the region of 00 times or less.

[0024] In a further preferred aspect of the present invention, the coefficient of friction is such that the cumulative number of revolutions of the optical recording medium is 1.
It is the value at the time of 000 times.

In a further preferred aspect of the present invention, the coefficient of friction is such that the cumulative number of revolutions of the optical recording medium is 1.
It is the value at the time of 0000 times.

In a further preferred aspect of the present invention, the coefficient of friction is a value after storage for 100 to 1000 hours in an environment of a temperature of 80 ° C. and a relative humidity of 5% or less.

[0027]

DETAILED DESCRIPTION OF THE INVENTION Referring to the accompanying drawings,
A preferred embodiment of the present invention will be described in detail.

FIG. 1 shows an optical recording medium 1 according to this embodiment.
It is sectional drawing which shows the structure of 0 roughly.

As shown in FIG. 1, an optical recording medium 10 according to this embodiment has a substrate 11 having a thickness of about 1.1 mm.
And a reflective layer 12 having a thickness of 70 to 130 nm and a thickness of 1
Recording layer 13 having a thickness of 00 to 250 nm and a thickness of 5 to 300 μm
and a hard coat layer 15 having a thickness of 0.5 to 10 μm. Also, the optical recording medium 1
A hole 16 is provided in the central portion of 0. The substrate 11 is made of polycarbonate, and the reflective layer 12 is made of an alloy containing silver as a main component. The recording layer 13 has a multi-layer structure in which a dielectric film is sandwiched between the upper and lower sides of a phase change film on which data is actually recorded. Further, the light transmission layer 14 and the hard coat layer 15 are made of an ultraviolet curable resin or a resin sheet such as polycarbonate or polyolefin. At the time of reading data from the optical recording medium 10 having such a structure, a reading laser is irradiated from the hard coat layer 15 side to detect the difference in reflected light amount. Further, when writing data to the optical recording medium 10, a writing laser is irradiated from the hard coat layer 15 side to change the state of the recording layer 13 (the crystal structure of the phase change film).
In the present specification, the light transmitting layer 14 and the hard coat layer 1
5 may be collectively referred to as a “translucent substrate”.

In the optical recording medium 10 according to this embodiment, the coefficient of friction of the surface of the hard coat layer 15 is 1.5 or less, preferably 1.0 or less, and more preferably 0.8 or less. . In order to obtain such a value as the friction coefficient of the surface of the hard coat layer 15, it is effective to make the hard coat layer 15 contain a lubricant. As the lubricant, it is preferable to select a silicone-based lubricant, a fluorine-based lubricant, or a fatty acid ester-based lubricant, and the content thereof is preferably about 0.1 to 5.0% by mass. Further, the optical recording medium 10 according to the present embodiment
In, after being stored in a high temperature environment for a long time, specifically, after being stored in an environment of a temperature of 60 to 90 degrees and a relative humidity of 30% or less, preferably 5% or less for 100 to 1000 hours. The friction coefficient of the surface of the hard coat layer 15 preferably has the above value. Further, it is more preferable that the friction coefficient of the surface of the hard coat layer 15 has the above value even after being stored in a high temperature and high humidity environment for a long time.

Next, a method of measuring the friction coefficient of the surface of the hard coat layer 15 will be described.

FIG. 2 is a diagram for explaining a method of measuring the friction coefficient of the surface of the hard coat layer 15.

As shown in FIG. 2, the hard coat layer 1
In the measurement of the friction coefficient of the surface of No. 5, the rotation mechanism 1 for rotating the optical recording medium 10 according to the present embodiment, the measuring thin film piece 2 as the measuring member, and the measuring thin film piece 2 are the measurement targets. A weight 3 that is pressed against the surface of the optical recording medium and a transducer 4 that detects the tensile force generated on the thin film piece for measurement 2 are used.

The thin film piece 2 for measurement is used to convert the frictional force generated between the thin film piece 2 for measurement and the surface of the rotating optical recording medium (here, the surface of the hard coat layer 15) into tensile force, and is not particularly limited. However, since it is possible to effectively judge the difference in the surface characteristics of each optical recording medium, it is preferable that the material is a fiber aggregate, and in particular, a fiber formed mainly by an organic substance by spinning / press bonding. Aggregation,
For example, it is preferable to use a self-adhesive long-fiber nonwoven fabric containing cellulose as a main component.

The weight 3 has a cylindrical shape with a flat bottom surface,
On the bottom surface, the load on the thin film piece 2 for measurement is planarly applied.
The cushioning material 5 is provided so as to be even. Especially limited
Polyurea is not used as a cushioning material.
It is preferable to use tongue, silicone rubber or the like. Well
Also, the bottom area of the weight 3 is 0.5 mm^Two~ 900 mm
^TwoIt is preferable that the load on the thin film piece for measurement 2 is
0.5g / cm^Two~ 50g / cm^TwoLike to be
Good

In measuring the frictional characteristics, first, the optical recording medium 10 according to the present embodiment is placed on the rotary table (not shown) of the measuring device with the hard coat layer 15 facing upward, and then, The measuring thin film piece 2 and the weight 3 are placed on the surface of the optical recording medium 10. In this state, the rotating mechanism 1 is operated to move the optical recording medium 10 to 50 to 3000 rp.
m, preferably 100-1500 rpm.
This state is shown in FIG.

At this time, the surface of the optical recording medium 10 and the weight 3
The measurement thin film piece 2 is pulled in the rotation direction of the optical recording medium 10 by the frictional force generated between the measurement thin film piece 2 and the measurement thin film piece 2 which is loaded by The tensile force is converted into an electric signal by the transducer 4, which makes it possible to specify the frictional characteristics of the surface of the optical recording medium 10, that is, the frictional force and / or the friction coefficient.

The friction characteristic of the surface of the optical recording medium 10 is measured by such a method by measuring the friction characteristic of the surface of the magnetic field modulation head side, not the optical pickup side of the MD (mini disk) which is a magnetic field modulation type optical recording medium. It is characterized by being accurate and having good reproducibility as compared with the case of using an apparatus for measurement. Here, MD (mini disk)
Is a device used to measure the frictional force and / or the coefficient of friction of the surface on the side contacted by the magnetic field modulation head, and is related to the measurement using such a device. Is described on page 20 of the appendix to the Minidisk system standard (RainbowBook). Such a measuring device is not suitable for measuring the frictional force and / or the frictional coefficient of the light incident surface of an optical recording medium of the type in which data is recorded / reproduced without making physical contact.

In the optical recording medium 10 according to the present embodiment, the friction coefficient of the surface of the hard coat layer 15 measured by the method described above is set to 1.5 or less as described above. Therefore, in recording / reproducing data on / from the optical recording medium 10, a high N of about NA = 0.85 is obtained.
Even when the A lens is used and the working distance (working distance) between the objective lens and the surface (hard coat layer 15) of the optical recording medium 10 is set to about 100 μm, the optical recording medium 10 is rotated during rotation. Optical recording medium 10
Since the occurrence of scratches due to the contact between the surface of the (hard coat layer 15) and the objective lens or the support that supports the objective lens is suppressed, the reliability can be significantly improved.

In particular, if the friction coefficient of the surface of the hard coat layer 15 is set to 1.0 or less, the occurrence of such scratches can be suppressed more effectively, and further, the hard coat layer 1
If the friction coefficient of the surface of No. 5 is set to 0.8 or less, the occurrence of such scratches can be suppressed more effectively.

[0041]

【Example】Example 1 15 sheets of light with different hard coat layers
Friction on the surface of recording media (Sample # 1 to Sample # 15)
The coefficient was measured using the friction property measuring method described above.

In this measurement, as the thin film piece 2 for measurement, a non-woven fabric having a length of 100 mm and a width of 25 mm (manufactured by Asahi Kasei Co., Ltd., Bencott lint-free CT) was used.
-8) was used. Here, the length of the thin film piece 2 for measurement means
This is the direction in which the pulling force acts, and in FIG. As the weight 3, a weight having a diameter of 20 mm and a weight of 31 g was used. The weight 3 was placed so that its center was located at a distance of 40 mm from the center of the optical recording medium. Under these conditions, the rotation speed of the optical recording medium by the rotating mechanism 1 was set to 670 rpm, and the friction coefficient was measured for each optical recording medium.

Here, in the 15 optical recording media (Sample # 1 to Sample # 15) to be measured, all of the hard coat layers 15 were UV curable resins (manufactured by Nippon Kayaku Co., Ltd., HOD- 3200) and different kinds and amounts of lubricants added to the ultraviolet curable resin were prepared. Table 1 shows the types and addition amounts of the lubricant contained in the hard coat layer 15 of each sample.
Further, in all the samples, the thickness of the hard coat layer was 3.5 μm.

[0044]

[Table 1] FIG. 3 is a graph showing the measurement results of the friction coefficient of Samples # 1 to # 5, and FIG. 4 is a graph showing the measurement results of the friction coefficient of Samples # 6 to # 10.
FIG. 5 is a graph showing the measurement results of the coefficient of friction of Sample # 11 to Sample # 15. 3 to 5,
The vertical axis represents the coefficient of friction, and the horizontal axis represents the cumulative number of rotations of the optical recording medium. Referring to FIGS. 3 to 5, the hard coat layer 1
It can be seen that the larger the amount of lubricant contained in 5, the lower the coefficient of friction.

Further, referring to FIGS. 3 to 5, for all the samples, the initial state (cumulative rotation speed = 100)
It can be confirmed that the coefficient of friction is less than 0.8 in (less than or equal to times). The friction coefficient in the initial state (cumulative rotation speed = 100 times or less) means the friction coefficient of the surface of the hard coat layer 15 in the state (new state) immediately after the production of each sample. Therefore, in each of the samples, the coefficient of friction of the surface of the hard coat layer 15 in a state immediately after production (new state) is extremely low (0.8 or less).
I understand.

Further, referring to FIGS. 3 to 5, Samples # 3 and # 3 having a lubricant content of 1.0 wt% or more.
4, # 5, # 8, # 9, # 10, # 13, # 14, # 1
No. 5, sample # 1 having a friction coefficient of 0.8 or less at a cumulative number of revolutions of 1000 and a lubricant content of 0.1% by mass or 0.5% by mass,
It can be confirmed that the friction coefficient of # 2, # 6, # 7, # 11, and # 12 is 1.0 or less at the time when the cumulative number of rotations is 1000 times. In each sample, the friction coefficient at the time when the cumulative rotation speed is 1000 times is higher than the friction coefficient in the initial state (cumulative rotation speed = 100 times or less) is that the lubricant contained in the hard coat layer 15 is measured. This is because it was wiped by the thin film piece 2.
That is, the friction coefficient at the time when the cumulative number of rotations is 1000 is the hard coat layer after the user frequently wipes dust and dirt adhering to the surface of the light incident surface of the optical recording medium with a non-woven fabric, tissue paper or the like. 15 means the coefficient of friction of the surface. Therefore, the coefficient of friction of the surface of the hard coat layer 15 after the user frequently wipes dust and dirt adhering to the surface of the light incident surface of the optical recording medium with a non-woven fabric, tissue paper, etc. Samples # 3, # 4, # 5, # with 1.0 wt% or more
Sample # 1 in which # 8, # 9, # 10, # 13, # 14, and # 15 are very low (0.8 or less) and the lubricant content is 0.1% by mass or 0.5% by mass , # 2, #
6, # 7, # 11, and # 12 are sufficiently low (1.
(0 or less).

Further, referring to FIGS. 3 to 5, samples # 4, # having a lubricant content of 3.0 wt% or more are used.
Regarding Nos. 5, # 9, # 10, # 14, and # 15, the coefficient of friction was 0.8 or less when the cumulative number of revolutions was 10,000, and the content of the lubricant was 0.5% by mass or 1%. 0.0% by weight of Samples # 2, # 3, # 7, # 8,
It can be confirmed that the friction coefficient of # 12 and # 13 is 1.0 or less at the time when the cumulative number of rotations is 10,000. Further, it can be confirmed that the friction coefficient is 1.5 or less at the time when the cumulative number of rotations is close to 10,000 times in all the samples. Here, the friction coefficient at the time when the cumulative number of rotations is 10000 times or in the vicinity thereof means that the user very often wipes dust and dirt adhering to the surface of the light incident surface of the optical recording medium with a non-woven fabric or a tissue paper. And the coefficient of friction of the surface of the hard coat layer 15 after being frequently wiped with a waste cloth containing water or a detergent solution. Therefore, the coefficient of friction of the surface of the hard coat layer 15 after the user frequently wipes dust and dirt adhering to the surface of the light incident surface of the optical recording medium with a non-woven fabric, tissue paper, etc. Sample # 4 with 3.0 wt% or more,
Samples # 2, # having very low levels of # 5, # 9, # 10, # 14, and # 15 (0.8 or less) and a lubricant content of 0.5% by mass or 1.0% by mass. 3, # 7, #
It can be seen that the values of 8, # 12, and # 13 are sufficiently low (1.0 or less), and all of the samples are suppressed to some extent (1.5 or less).

[0048]Example 2 Next, the samples # 1, # 3, # 5, # 6, and
The same 9 sheets as # 8, # 10, # 11, # 13 and # 15
Samples are prepared and these are kept at a temperature of 80 degrees and a relative humidity of 5% or less.
It stored for 200 hours under the following environment. Then the above example
Measure the coefficient of friction on the surface of each sample in the same way as in 1.
went.

In FIG. 6, # 1, # 3, # 5, # 6, # 8,
It is a graph which shows the measurement result of the friction coefficient of # 10, # 11, # 13, and # 15. In FIG. 6, the vertical axis represents the coefficient of friction and the horizontal axis represents the cumulative number of rotations of the optical recording medium. Referring to FIG. 6, when the temperature is 80 degrees and the relative humidity is 5% or less,
It can be seen that, even after storage for 00 hours, each sample has substantially the same characteristics as those obtained in Example 1.

As described above, in the optical recording medium 10 according to the present embodiment, since the hard coat layer 15 serving as the light incident surface has a low friction coefficient, the surface of the light incident surface is scratched. It has the characteristic of being hard to stick to. Therefore, recording / recording of data on / from the optical recording medium 10 is performed.
In the reproduction, a high NA lens with NA = 0.85 is used, and the working distance (working distance) between the objective lens and the surface (hard coat layer 15) of the optical recording medium 10 is set to about 100 μm. Even if the surface of the optical recording medium 10 (the hard coat layer 15) is in contact with the objective lens or the support that supports the objective lens during the rotation of the optical recording medium 10, the occurrence of scratches is suppressed. It is possible to significantly improve the sex.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. It goes without saying that it is a thing.

For example, the structure of the optical recording medium 10 according to the above embodiment is an example of the optical recording medium to which the present invention is preferably applied, and the structure of the optical recording medium to which the present invention is applied is not limited thereto. Not something. Therefore, the optical recording medium according to the present invention may be a read-only optical recording medium. Further, the optical recording medium according to the present invention may be a magnetic field modulation type optical recording medium such as a magneto-optical recording medium. In this case, it is not the side in contact with the magnetic head but the incident surface of the recording / reproducing light. Friction coefficient is set to 1.5 or less. However, the effect of suppressing the occurrence of scratches due to the reduction of the friction coefficient of the surface of the light incident surface is prominent when contact is made with the objective lens or the support body that supports the objective lens. It is particularly suitable for an optical recording medium in which the light transmission layer 14 is thinned to about 5 to 300 μm.

Further, the optical recording medium 1 according to the above embodiment.
In the measurement of the friction coefficient of 0, the weight 3 having a flat bottom surface is used to bring the surface of the optical recording medium and the thin film piece 2 for measurement into contact with each other by applying a uniform load in plan view. May be applied to the measurement thin film piece 2 by any method as long as they are brought into contact with each other by applying a uniform load on the plane. Further, instead of the thin film piece for measurement, a measurement member having a sufficient weight for effective measurement is used, and the weight 3 is not used, and friction with the surface of the optical recording medium 10 is caused by its own weight. I don't mind getting.

Furthermore, in the measurement of the friction coefficient of the optical recording medium 10 according to the above embodiment, the weight 3 having a cylindrical shape is used, but the shape of the weight 3 is a cylindrical shape as long as the bottom surface is flat. It is not mandatory to be there.

[0055]

As described above, in the present invention, since the friction coefficient of the surface of the optical recording medium on the light incident surface side is reduced, the surface on the light incident surface side is not easily scratched. Therefore, according to the present invention, it is possible to provide a highly reliable optical recording medium.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing the structure of an optical recording medium 10 according to a preferred embodiment of the present invention.

FIG. 2 is a diagram for explaining a method of measuring the friction coefficient of the surface of the hard coat layer 15.

FIG. 3 is a graph showing measurement results of friction coefficients of Sample # 1 to Sample # 5.

FIG. 4 is a graph showing measurement results of friction coefficients of Sample # 6 to Sample # 10.

FIG. 5 is a graph showing measurement results of friction coefficients of Sample # 11 to Sample # 15.

FIG. 6 Samples # 1, # 3, # after storage test
It is a graph which shows the measurement result of the friction coefficient of 5, # 6, # 8, # 10, # 11, # 13, and # 15.

[Explanation of symbols]

1 rotation mechanism 2 Thin film piece for measurement 3 weights 4 transducer 5 cushioning material 10 Optical recording medium 11 board 12 Reflective layer 13 recording layer 14 Light transmission layer 15 Hard coat layer 16 holes

Claims (13)

[Claims] 1. A substrate, an information recording layer provided on the substrate, and a translucent substrate provided on the information recording layer, and the information recording layer is provided on the information recording layer via the translucent substrate. An optical recording medium for recording / reproducing data by irradiating a laser beam, wherein the optical recording medium is 50-3000.
It is measured by applying a planar load of 5 to 50 g / cm ₂ to the surface of the translucent substrate through a self-adhesive long-fiber nonwoven fabric containing cellulose as a main component while rotating at a rotation speed of rpm. An optical recording medium having a friction coefficient of 1.5 or less. 2. The optical recording medium according to claim 1, wherein the friction coefficient is a value when the rotation speed of the optical recording medium is set to 100 to 1500 rpm. 3. The friction coefficient of the surface of the translucent substrate is 1.
It is 0 or less, The optical recording medium of Claim 1 or 2 characterized by the above-mentioned. 4. The friction coefficient of the surface of the translucent substrate is 0.
The optical recording medium according to claim 3, wherein the optical recording medium is 8 or less. 5. The optical recording medium according to claim 1, wherein the translucent substrate comprises a light transmissive layer and a hard coat layer provided on the surface thereof. 6. The optical recording medium according to claim 5, wherein the light transmitting layer has a thickness of 5 to 300 μm. 7. The optical recording medium according to claim 5, wherein the hard coat layer contains a lubricant. 8. The optical recording medium according to claim 7, wherein the lubricant is a silicone lubricant, a fluorine lubricant or a fatty acid ester lubricant. 9. The optical recording medium according to claim 7, wherein the content of the lubricant is 0.1 to 5.0 mass%. 10. The optical recording medium according to claim 1, wherein the coefficient of friction is a value in a region where the cumulative number of rotations of the optical recording medium is 100 times or less. 11. The optical recording medium according to claim 1, wherein the coefficient of friction is a value at a time when the cumulative number of rotations of the optical recording medium is 1000 times. 12. The optical recording medium according to claim 1, wherein the friction coefficient is a value at the time when the cumulative number of rotations of the optical recording medium is 10,000 times. 13. The coefficient of friction is a temperature of 80 degrees, 5%
The value after being stored for 100 to 1000 hours in the following relative humidity environment.
3. The optical recording medium according to any one of 2.