JPH04163737A - Optical tape - Google Patents

Abstract

PURPOSE:To enable the obtaining of an optical tape better both in recording/ reproduction characteristic and tape running property by specifying an average roughness at the center line of a surface desired to form a recording layer of an intermediate layer between a base film and the recording layer while the average roughness at the center line of a surface on the side opposite to the intermediate layer forming surface of the base film is specified. CONSTITUTION:Average roughness is set below 50Angstrom at the center line of a surface desired to form a recording layer of an intermediate layer between a base film 3 and the recording layer 2 while the average roughness is set at 50-1000Angstrom at the center line of a surface on the side opposite to the intermediate layer forming surface of the base film 3. In other words, the base film 3 herein used is preferably 100-1000Angstrom in the center line average roughness and the intermediate layer is provided on the side of the recording layer forming surface to reduce the center line average roughness. Material herein used for the base film is a resin such as polyethylene terephthalate, polyimide, polyvinyl chloride or polycarbonate. This enables the obtaining of an optical tape better both in recording/reproduction property and tape running property.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical tape, and in particular to an optical tape used as a recording medium in an optical recording and reproducing device, which has both recording and reproducing characteristics and tape runnability. This invention relates to a significantly improved optical tape.

[Prior Art] Conventionally, magnetic recording media have been generally used as information recording tapes, and in order to improve the information recording density, methods using optical recording and reproducing systems have been proposed.

However, the structure of such an optical tape is conventionally
Te-As-5e metal film on a plastic base film (JP-A-57-33447), Te-3e, 5e-In- on a polyimide tape substrate.
Sb-based and Ag-Zn-based alloys are RF-magnetronized.
A method in which a protective layer is formed by battering and a protective layer is further formed thereon (Japanese Patent Application Laid-Open No. 132251/1983) has been reported.

On the other hand, in order to smooth the running of the tape, a recording layer is formed on one side of the base film and an anti-reflection layer is formed on the other side. Optical tape with anti-friction and friction-reducing effects (
JP-A-1-286130) has been reported.

[Problems to be Solved by the Invention] However, in conventional optical tapes manufactured using base films with smooth tape running properties, when information is recorded and reproduced using an optical recording and reproducing system, it is difficult to record and reproduce information. There was a problem that good playback characteristics could not be obtained. Conversely, when a base film that provides good recording and reproducing characteristics in an optical recording and reproducing system is used, there is a problem in that smooth tape running properties cannot be obtained. this is,
If the surface roughness of the base film is rough, it will have excellent running properties, but the optical playback properties will be poor; conversely, if the surface flatness is improved, it will have excellent optical playback properties, but the tape running This is because the quality decreases.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide an optical tape having good recording/reproducing characteristics and tape running properties.

[Means for Solving the Problems] The optical tape of the present invention includes a base film and a recording layer provided on the base film via an intermediate layer.
In an optical tape capable of optically recording and reproducing information, the centerline average roughness of the recording layer forming surface of the intermediate layer is 50 Å or less, and the centerline of the surface of the base film opposite to the intermediate layer forming surface. It is characterized by an average roughness of 50 to 1000.

The present invention will be explained in detail below.

The optical tape of the present invention has a centerline average roughness of 50 to 1000, preferably 100 to 1000, on the surface opposite to the surface on which the recording layer is formed, and has an intermediate layer between the recording layer and the base film. is provided, and the center line average roughness of the surface on which the recording layer is formed is 50 Å or less. That is, in the present invention, a base film with a centerline average roughness of 50 to 1000, preferably 100 to 1000, is used, and an intermediate layer is provided on the side on which the recording layer is formed to reduce the centerline average roughness. .

Examples of the material for the base film used in the present invention include plastics such as polyethylene terephthalate, polyimide, polyvinyl chloride, and polycarbonate. Moreover, the thickness of such a base film is generally about 1 to 1100 LL.

In the present invention, a coating layer having particles dispersed therein is provided as a base film on the surface opposite to the recording layer formation surface of the base film having a centerline average roughness of less than 50. 50-1000 people, preferably 1
A film with a roughened surface of 0.00 to 1000 may also be used.

Examples of the intermediate layer provided on the recording layer forming side of the base film include a layer of ultraviolet curing resin, epoxy resin, acrylic resin, acrylic epoxy resin, melamine resin, phenol resin, urethane resin, and other thermosetting resins. It will be done. The thickness of such an intermediate layer is preferably about 0.05 to 20 μm.

Furthermore, as the recording medium formed on the intermediate layer, either a type that reads changes in reflectance or a type that reads rotation of the plane of polarization can be adopted. Further, the recording layer may have a layered structure in which a protective layer, an interference layer, and a reflective layer are laminated as necessary.

Methods for forming the recording layer (including a protective layer, interference layer, and reflective layer as necessary) include physical vapor deposition (PVD) such as sputtering, chemical vapor deposition (CVD) such as plasma CVD, etc. Applicable. Among these methods, to form a recording layer by the PVD method, a target of a predetermined composition is usually used to deposit a predetermined layer configuration on a base film by electron beam evaporation or sputtering. In addition, a method using ion blating can also be adopted.

In forming such a recording layer, if the film deposition rate is too fast, it will increase the film stress, and if it is too slow, it will affect the productivity. It is preferable to form.

[Function] The optical tape of the present invention has a relatively large center line average roughness of 50 to 1000 on the surface opposite to the surface on which the recording layer is formed of the base film, so that smooth and stable running properties can be ensured. I can do it.

Moreover, due to the interposition of the intermediate layer, the center line average roughness of the surface on which the recording layer is formed is as small as 50 Å or less, so that good recording and reproducing characteristics can be obtained using an optical recording and reproducing system.

[Examples] The present invention will be explained in more detail by giving Examples, Comparative Examples, and Reference Examples below, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. .

In addition, in the examples and comparative examples, the center line average roughness is J
Based on IS B 0651, the shape of the stylus is 0.2
This is a value measured using a stylus type surface roughness measuring device with a diameter of 0.2 μm.

Further, the physical property values of the base films (1) to (m) used in the following examples are as shown in Table 1 below.

Table 1 Example 1.2 Using PET film 1 (Example 1) or ■ (Example 2) having a center line average roughness shown in Table 1 and a thickness of 15 μm as the base film, the recording layer was formed. An ultraviolet curable resin layer was formed on the side surface by a coating method to a thickness of 5 μm to form an intermediate layer. The surface roughness of the recording layer forming surface at this time was as shown in Table 2. An optical tape was produced using the base film in which the intermediate layer was formed in this way.

That is, first, a base film is introduced into a magnetron sputtering apparatus, and after exhausting to a pressure of 5X10-'Pa or less,
r was introduced for 30 seconds, and the pressure was adjusted to 0.3 Pa. In this state, a Ta chip was placed on the A°C target and sputtering was performed to form a reflective layer of Al25tTas.
It was formed to a thickness of 0.00 people. Next, after evacuating the inside of the chamber, Ar was introduced for 30 seconds, the pressure inside the chamber was set to 0.3 Pa, and Tb and F e o oc O l were introduced.

A recording layer (magnetic layer) with a thickness of 400 mm was formed by simultaneous sputtering with the following targets. After that, after evacuating the chamber again, Ar was applied at 30 sccm and 02 was applied for 4 seconds.
ccm was introduced and the pressure was adjusted to 0.5 Pa. In this state, reactive sputtering was performed using a Ta target with an input power of 500 W to form a tantalum oxide interference layer of 75%.
Sample No. 1 with the following layer structure was formed to a thickness of 0.
2 was produced.

Each of the obtained samples was initialized in a magnetic field of 25 kOe at room temperature, and then the reproduction characteristics (noise characteristics) were measured using a magneto-optical optical head under the following conditions.

Direct foot presentation tape running speed: 2. Om/s Reproduction power: 0.6 mW Figure 1 shows the noise level at 500 kHz of each sample measured under the above conditions by irradiating a laser beam from the interference layer side.

In addition, running properties were investigated using the method shown in FIGS. 3 and 4.

That is, sample 1 is attached to the side of fixed drum 11,
The base film 3 used in the production of sample 1 was stretched over the fixed drum 11 and the rotating drum 12, and the recording layer 2 surface and the surface of the base film 3 were brought into contact with each other under a constant tension, and the rotating drum 12 was It was rotated at 1800 r, p, m, and the axial load at that time was measured. Furthermore, after the measurement, the presence or absence of defects on the tape surface was observed using a microscope.

Samples with poor running properties have a large initial axial load, and stable rotation cannot be obtained, and in severe cases, running in a contact state cannot be obtained. Furthermore, the occurrence of defects on the tape surface after measurement was also significant. The runnability was judged according to the following criteria based on the magnitude of the axial load and the state of defects on the tape surface after measurement, and the results are shown in Table 2.

1 tate j"Usu iLya ○... The shaft load is small, stable and smooth running is achieved, and there are almost no defects on the tape surface after measurement.

X: The axle load is large, making it difficult or impossible to drive.
There were also large defects on the tape surface after measurement.

In addition, in Table 2, the noise characteristics were evaluated based on the following criteria, and the results are also listed.

Noise ゛○...Noise level -60 dBm or less x...Noise level exceeds -60 dBm The results are shown in Table 2.

Comparative Example 1 Example 1 except that the film ■ shown in Table 1 with a center line average roughness of less than 50 was used as the base film.
Sample No. 3 was prepared in the same manner as above, and the noise characteristics,
The running performance was investigated.

The results are shown in FIG. 1 and Table 2.

Comparative Examples 2 to 4 Sample No. 2 was prepared in the same manner as in Example 1.2 and Comparative Example except that no intermediate layer was provided.

4.5.6 was produced and its noise characteristics and running performance were investigated.

The results are shown in Figure 2 and Table 2.

Reference Example Sample No. 7 was prepared in the same manner as in Example 1 except that a glass substrate for optical disk (mirror surface part) was used instead of the base film. Recording was performed under the following conditions, and the noise characteristics were determined, and the results are shown in FIGS. 1, 2, and Table 2.

Translation: Leave it to your mouth. Linear speed: 2. Om/s Playback power: 0.6mW Recording frequency: 500kHz Erase power: 4mW Erase magnetic field knee 3000e Recording power: 4mW Recording magnetic field: 2000e The following is clear from Table 2.

That is, even though an intermediate layer was provided, Sample No. 3 using a base film with a small center line average roughness had excellent noise characteristics but poor runnability. On the other hand, even if a base film with a large centerline average roughness is used, sample No. 4.5, which does not include an intermediate layer, has excellent running properties but poor noise characteristics. Also, sample No. 6
Although it does not have an intermediate layer, it has excellent noise characteristics because the center line average roughness of the base film is small. However, this sample No. 096 has poor running performance.

As described above, with the conventional method, it has not been possible to obtain a sample that is excellent in both playback characteristics and tape running properties in an optical recording/playback system.

On the other hand, sample No. according to the present invention.

1.2 provides an optical tape that has good noise characteristics similar to those of glass substrates for optical disks, exhibits good characteristics in optical recording and reproducing systems, and also has good tape running properties.

That is, in sample No. 1.2, a PET film having a large center line average roughness and good running characteristics was used.
By providing an ultraviolet curable resin layer as an intermediate layer on the side where the recording layer is formed of this PET film, the center line average roughness is reduced, thereby making it possible to obtain an optical tape that provides good playback characteristics in an optical recording and playback system. .

[Effects of the Invention] As detailed above, according to the optical tape of the present invention, good recording and reproducing characteristics can be obtained by the optical recording and reproducing system,
Moreover, an optical tape having good tape running properties is provided.

[Brief explanation of drawings]

Figures 1 and 2 are graphs showing the noise characteristics obtained in Examples, Comparative Examples, and Reference Examples, Figure 3 is a cross-sectional view explaining the running performance measurement method, and Figure 4 is the section ■ in Figure 3. This is an enlarged view. 1...sample, 2...recording layer, 3...
Base film, 11...Fixed drum, 12...
・Rotating drum. Agent Patent Attorney Tsuyoshi Shigeno

Claims (1)

[Claims] (1) In an optical tape capable of optically recording and reproducing information, which has a base film and a recording layer provided on the base film via an intermediate layer, the center line of the recording layer forming surface of the intermediate layer An optical tape having an average roughness of 50 Å or less, and a centerline average roughness of a surface of the base film opposite to the intermediate layer forming surface of 50 to 1000 Å.