JP2000146830A - Infrared microscope / FT-IR apparatus and method for analyzing recording medium - Google Patents

Abstract

[PROBLEMS] To provide an infrared microscopic / FT-IR apparatus and an analytical method capable of easily and accurately performing qualitative / quantitative analysis of an organic material on the surface of a high-density recording medium. An interference light source unit and a measurement unit are provided.
And a signal processing unit 30. In the measuring unit 20, a hemispherical prism 21 made of Ge, a variable incident angle device 22, and a detector 23 for sensing total reflected light from the sample surface are provided in a closed sample chamber. . Variable incident angle device 2
Reference numeral 2 denotes a pair of parabolic mirrors arranged opposite to each other. At the time of analysis using a single beam measuring device, the surface of the floppy disk as the sample S on the side where the magnetic layer is formed is brought into close contact with the bottom surface of the prism with a contact pressure of 10 kgf / cm ² or less.
The incident angle θ of the infrared light with respect to the prism is scanned, and the spectrum of the infrared light totally reflected on the sample surface is converted to the FT-I
Analyze with an R device. The same operation is performed for the reference R to obtain a profile of the organic lubricant content in the depth direction in the sample magnetic layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a prism is brought into close contact with the surface of a sample, infrared rays are incident on the prism at an arbitrary angle, and the spectrum of the infrared ray totally reflected on the sample surface is measured by FT.
The present invention relates to an infrared microscopic / FT-IR apparatus based on an attenuated total reflection method for analyzing a sample surface by analyzing with an IR apparatus, and a method for analyzing a high-density recording medium by using the apparatus.

[0002]

2. Description of the Related Art Magnetic recording media are widely used as audio tapes, video tapes, backup data cartridges, floppy disks, hard disks and the like. In particular, recently, studies on shortening the recording wavelength or high-density recording such as a digital recording method have been actively conducted, and the development of a magnetic recording medium having excellent electromagnetic conversion characteristics has been demanded.

[0003] In a coating type magnetic recording medium which is currently mainstream, thinning of a magnetic layer is being studied in order to improve electromagnetic conversion characteristics. This is a method for improving the electromagnetic conversion characteristics by reducing the self-demagnetization loss during recording, and various coating methods have been proposed in recent years.

[0004] In general, the surface is smoothed in order to minimize the spacing loss during recording and reproduction. In high-density recording, since the recording wavelength used is short, it is easily affected by surface roughness, and control of surface roughness is particularly important.

As described above, as the output of the magnetic tape increases, the smoothness of the surface of the magnetic layer must be made extremely good. Large contact area. Therefore, the coefficient of friction is increased, and the adhesion phenomenon (so-called sticking) is apt to occur, so that the magnetic tape lacks running properties and durability.

In order to solve these problems, the use of various organic lubricants has been studied. Conventionally, higher fatty acids or esters thereof have been added to the magnetic layer of the magnetic recording medium. Attempts have been made to lower the coefficient of friction by top coating or the like.

However, a method for quantitatively measuring the amount of the lubricant present on the surface of the magnetic recording medium and in the medium is as follows.
The only reality is that there is no other way to extract and analyze the lubricant with a solvent. However, this extraction method can only measure lubricants that dissolve in solvents (hexane, toluene, etc.).
In addition, measurement takes a very long time. Therefore, in the manufacturing process of the magnetic recording medium, it is very difficult to control the amount of the lubricant to be applied.

On the other hand, recording / recording represented by a hard disk
In a magnetic recording apparatus including a reproducing magnetic head and a magnetic recording medium as main components, a frictional force is generated between the magnetic head and the magnetic recording medium, which causes wear and tear of the magnetic head and the magnetic recording medium. Becomes When the wear damage reaches the magnetic layer, the information recorded on the magnetic layer is destroyed, which causes a so-called head crash phenomenon.To prevent this head crash, it is necessary to secure the reliability of the magnetic recording device. is important.

In order to prevent head crash, it is necessary to improve the wear resistance of the magnetic recording medium itself. Therefore, the magnetic layer is usually covered with a protective layer made of carbon, oxide, carbide, nitride, and the like. A lubricating film is formed on the protective layer. Such a lubricating film generally requires characteristics such as low surface energy, heat resistance, chemical stability, and lubricity. US Pat. No. 3,778,308 discloses a compound for forming a lubricating film. The perfluoroalkyl polyether-based or perfluoroalkyl compounds described in the specification are currently most frequently used.

[0010] Currently, the mainstream magnetic recording devices include:
A method of performing recording / reproduction by forming a space at a fixed interval between a magnetic head and a surface of a magnetic recording medium is used. This constant interval is called a flying height. In order to increase the recording density on a magnetic recording medium, it is necessary to further reduce the flying height of a magnetic head. However, as the density of magnetic recording devices has been increasing at a rapid pace in recent years, the flying height has been continuously decreasing. I am following. In recent years, as a limit of the flying height, a method of performing recording / reproduction while keeping a magnetic head in constant contact with the surface of a magnetic recording medium, that is, a so-called contact recording method has been proposed.

When the flying height decreases in this manner, the time required for the magnetic head and the surface of the magnetic recording medium to slide inevitably increases, so that the continuous sliding durability of the lubricating film is increased to increase the dynamic friction coefficient and the like. It is necessary to reduce wear. Further, in a magnetic recording apparatus employing such an extremely low flying system or a contact recording system, the surface roughness and undulation of the disk are reduced, so that a high maximum static friction force (adhesion) is easily generated between the head and the disk. . The sticking causes the disk not to start or the head to be damaged.

A major cause of sticking is the thickness of a lubricating film existing on the surface of a magnetic disk. Methods for quantifying the amount of lubricant present on the magnetic disk include an ellipsometer and XPS. With an ellipsometer, the roughness of the magnetic disk surface greatly affects the measurement, so that it is difficult to accurately measure the amount of the lubricant. Further, in XPS, since the measurement is performed in a vacuum, the lubricant on the surface of the magnetic disk disappears, and measurement using fluorine atoms is not suitable for measurement of a hydrocarbon-based lubricant.

As for an optical disk (phase change, magneto-optical, etc.), the spacing between the conventional disk and the optical head is several hundred nm to several μm, which is much larger than that of other magnetic recording systems. Therefore, a protective film having a thickness of about several hundred μm is formed on the recording layer. As described above, in the conventional optical disk, since the spacing is large, the protective layer and the like can be formed thick, and there is a sufficient margin for considering the tribological characteristics.

However, when performing optical recording in the near field where research and development are currently being carried out, the spacing between the recording layer and the optical head is considered to be 100 μm or less.
The thickness of the protective layer must be several tens nm or less. Therefore, the tribological characteristics required for near-field optical recording are almost the same as those required for current magnetic disks and the like. It has been considered to apply an organic thin film of about several nm as a lubricant layer on the disk surface. Therefore, in the case of an optical disk, it is necessary to study the amount of coating and the orientation of the lubricating film on the disk as in the case of the magnetic disk and the like.

As described above, the qualitative analysis and quantitative analysis of the lubricant on the medium surface and in the medium have conventionally relied on elemental analysis such as XPS. However, since this elemental analysis is usually performed in a vacuum, there is a concern that the lubricant may volatilize. In addition, atoms such as carbon and hydrogen cannot be distinguished from lubricants because they are always present as contaminants on the medium surface. Therefore, only when the fluorine atom is contained in the lubricant, the amount of the lubricant can be measured only from the fluorine atom amount.

Usually, compounds used as a lubricant include perfluoropolyether containing a fluorine atom,
Since there are hydrocarbon fatty acids and fatty acid esters other than perfluoroalkyl compounds, this method cannot be applied to the analysis of all lubricant compounds. In addition, in the high-sensitivity reflection absorption infrared spectroscopy, the absorption of the nonmagnetic support cannot be sufficiently removed, and the spectrum of the nonmagnetic support overlaps with the spectrum of the lubricant present thereon. It is very difficult to determine the spectrum.

[0017]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optical analyzer which can easily and accurately perform qualitative and quantitative analysis of an organic thin film on a high-density recording medium and an organic material in the medium. In other words, infrared microscopy
An object of the present invention is to provide an FT-IR apparatus and a method for analyzing a high-density recording medium using the FT-IR apparatus.

[0018]

In order to achieve the above object,
The infrared microscopic / FT-IR apparatus according to the present invention is configured such that a prism is brought into close contact with a sample surface, infrared light is incident on the prism at a predetermined angle, and the spectrum of the infrared light totally reflected on the sample surface is converted to an FT-IR. In the infrared microscopic / FT-IR device based on the attenuated total reflection method, which analyzes the surface of the sample by analyzing with the device, a hemispherical prism with a flat bottom surface is provided as a prism, and the sample mounting part is The optical system is characterized in that an incident optical system is provided with a variable incident angle optical system which is separated from each other by the hemispherical prism.

The present invention also relates to the infrared microscopic / FT-IR
The apparatus is characterized in that the optical system capable of changing the incident angle is housed in a closed sample chamber.

The present invention also relates to the infrared microscopic / FT-IR
In the apparatus, the optical system capable of changing the incident angle includes parabolic mirrors facing each other.

The present invention also relates to the infrared microscopic / FT-IR
The apparatus is characterized in that a contact pressure control device for finely adjusting the contact pressure between the bottom surface of the hemispherical prism and the sample surface is provided.

Further, the infrared microscopic / FT-IR according to the present invention
The apparatus analyzes the sample surface by attaching a prism to the sample surface, injecting infrared light into the prism at a predetermined angle, and analyzing the spectrum of the infrared light totally reflected on the sample surface with an FT-IR device. In the infrared microscopic / FT-IR apparatus based on the attenuated total reflection method, a hemispherical prism having a flat bottom surface is provided as a prism, and the adhesion pressure between the bottom surface of the hemispherical prism and the sample surface is reduced. A contact pressure control device for fine adjustment is provided.

Further, a method of analyzing a recording medium according to the present invention is characterized in that at least one of qualitative analysis and quantitative analysis of the surface of a sample is performed on the recording medium using the infrared microscopic / FT-IR apparatus. And

According to the present invention, in the method for analyzing a recording medium, the recording medium may be a non-magnetic support comprising a binder and a ferromagnetic powder as main components and a coating film of a magnetic paint containing an organic lubricant. It is a coating type magnetic recording medium having a magnetic layer formed thereon.

According to the present invention, there is provided the method for analyzing a recording medium, wherein the recording medium comprises a non-magnetic support, a thin metal film and a magnetic layer containing an organic lubricant formed on the thin metal film. A magnetic recording medium.

The present invention also provides the method for analyzing a recording medium, wherein the recording medium comprises an optical recording layer formed on a non-magnetic support, and an organic thin film containing an organic lubricant on the surface of the optical recording layer. It is characterized by being a formed thin film metal type optical recording medium.

According to the present invention, in the above-mentioned method for analyzing a recording medium, infrared light having a wavelength of 2 μm to 20 μm is incident.

Further, the present invention is characterized in that in the method for analyzing a recording medium, a hemispherical prism having a refractive index of 2.0 to 4.5 is used.

In the method for analyzing a high-density recording medium according to the present invention, it is preferable that the contact pressure control device sets the contact pressure between the sample surface under analysis and the bottom surface of the hemispherical prism to 10 kgf / cm ² or less.

In the present invention, the contact pressure is set to 1 as described above.
The reason that the infrared light is made incident on the prism while maintaining it at 0 kgf / cm ² or less is to make the sample surface and the bottom surface of the prism uniformly adhere over the entire contact surface thereof. A highly accurate analysis of the surface position can be performed, and an analysis result with good reproducibility can be obtained. When the sample is a recording medium such as a floppy disk, a magnetic tape, a magnetic disk, and an optical disk, the contact pressure is set to 10 kgf / cm.
^If it is higher than ² , the sample may be damaged, making analysis impossible.

As the contact pressure control device, a metal indenter, a pressing mechanism for bringing the metal indenter into close contact with the sample surface,
A pressure detecting mechanism for detecting a contact pressure between the sample surface and the bottom of the prism; and a control for appropriately moving the metal indenter by the pressing mechanism based on data detected by the pressure detecting mechanism to control the contact pressure within a predetermined range. And a mechanism having a mechanism. Specifically, the metal indenter is brought into close contact with the sample surface by a spring or a hydraulic mechanism, and the above-mentioned contact pressure is sensed by a sensor such as a piezoelectric element connected to the control mechanism.When the contact pressure is out of a predetermined range,
The pressing mechanism is operated by the control mechanism to move the metal indenter appropriately.

The high-density recording medium that can be analyzed according to the present invention includes: (1) a recording medium comprising a binder and ferromagnetic powder as a main component on a nonmagnetic support, and a magnetic medium containing an organic lubricant; A coating type magnetic recording medium in which a magnetic layer is formed by a paint film, (2) a metal thin film on a non-magnetic support,
A thin-film metal-type magnetic recording medium in which a magnetic layer containing an organic lubricant is formed on the metal thin film; and (3) an optical recording layer is formed on a non-magnetic support, and a surface of the optical recording layer is formed on the non-magnetic support. An example is a thin film metal type optical recording medium on which an organic thin film containing an organic lubricant is formed. Specific examples of these high-density recording media include magnetic tapes (audio tapes and video tapes), floppy disks, optical disks (magneto-optical disks, phase-change optical disks), and hard disks.

That is, according to the present invention, at least one of a qualitative analysis and a quantitative analysis of an organic material, particularly an organic lubricant, internally added or top-coated to the high-density recording medium can be simply and accurately performed. . The above-mentioned top-coated lubricant is a lubricant existing on the uppermost surface (the side opposite to the support) of the recording medium, and the internally added lubricant is in the medium, that is, the surface of the support and the recording medium. Lubricant present in the layer between the top surface. In the following, the organic lubricant may be abbreviated as a lubricant and the recording medium may be abbreviated as a medium.

In the method for analyzing a high-density recording medium according to the present invention, light in the infrared region having a wavelength of 1 μm to 20 μm is used, and the surface of a measurement sample (hereinafter sometimes referred to as a sample) is formed on the bottom surface of a hemispherical prism. (Smooth plane) with a predetermined contact pressure, and infrared light is incident on the spherical surface of this hemispherical prism (hereinafter, may be abbreviated as prism), and evanescent leaks from internal reflection in the prism. After obtaining a spectrum of an organic substance in the uppermost layer portion (depth 100 nm to several nm) of the sample surface by a wave, this is analyzed by a Fourier transformer. For the prism, a crystal that is transparent in the infrared region and has a refractive index as high as possible is used. A typical example is germanium (G
e) and silicon (Si).

In the ordinary high-sensitivity reflection-absorption infrared spectroscopy, light incident from a light source is absorbed by the sample unless the reflectance of the sample surface is considerably large, so that satisfactory measurement cannot be performed. This reflectivity is low for metal thin film type magnetic recording media, coating type magnetic recording media, and optical recording media, and it is impossible to analyze very small amounts of lubricant on the media surface and in media by high sensitivity reflection absorption infrared spectroscopy It is.

That is, in the above-mentioned high-sensitivity reflection-absorption infrared spectroscopy, measurement is performed by making light incident on the sample surface at an angle of about 80 ° and reflecting light on the sample surface. Use. The sample is generally suitable for analyzing organic substances on the surface of a metal base film having high reflectance, and is effective for analyzing organic substances on a hard disk. However, since the reflectance of a recording medium is usually very low (magnetic tape, floppy disk, etc.), analysis of organic substances is completely impossible with this analysis method. On the other hand, according to the present invention, highly accurate analysis can be performed on various types of samples regardless of the degree of reflectance.

In the ATR method (attenuated total reflection method using multiple reflection) using ordinary internal reflection infrared spectroscopy, samples are superimposed on both upper and lower surfaces of a plate-like prism, and a backing and a backing are provided on the back of each sample. A plate for fastening is stacked, and the whole is fastened with bolts and nuts, and this is set in a measuring device for analysis. However, in this method, it is very difficult to perform high-precision analysis because fine adjustment is required to bring the plate-like prism and the sample surface into uniform contact over the entire surface.
Further, when the amount of the object to be measured is different depending on the position on the sample surface, only the average value can be obtained. The distribution cannot be determined.

On the other hand, in the present invention, a hemispherical prism is used, and the contact pressure between the sample surface and the bottom surface of the prism is set within a predetermined range, so that both surfaces are brought into uniform contact over a wide range. In this case, the infrared light incident on the prism can be simply and reliably focused on a predetermined position on the sample surface. Therefore, it is possible to perform qualitative analysis and quantitative analysis of a trace amount of lubricant present on the surface of the medium and in the medium with high precision, and to have extremely high sensitivity for a minute region (a portion having a radius of 1 mm or less) on the sample surface. (High S / N ratio), the lubricant concentration can be determined.

When analyzing the lubricant of the recording medium according to the present invention, in order to perform a highly accurate analysis with good reproducibility, the difference in the adhesion pressure between the prism bottom surface and the sample surface in each analysis is several tens mgf / cm. it is necessary to control the ² within, and in accordance with the contact pressure control device, it was confirmed in studies by the present inventors can control the difference between the contact pressure at each time analyzed within a few mgf / cm ² ing.

In the present invention, infrared light having a wavelength of 2 μm to 20 μm is generally used. The reason is that organic materials have characteristic absorption characteristics over a wide infrared light range,
This is because most organic materials are absorbed in the wavelength region of light of 20 μm.

According to the present invention, 1 to 1
To analyze with high precision over a depth range of 2 μm, a hemispherical prism having a refractive index of 1.0 to 5.0, preferably 2.0 to 4.5 is used. In the present invention, the higher the refractive index of the prism, the more advantageous the analysis of the outermost surface of the sample. The smaller the refractive index, the more difficult the analysis of the outermost surface of the sample because infrared light penetrates deeper into the inside of the sample.

That is, in the analysis method of the present invention, light is totally reflected at the interface between the prism and the sample surface. At this time, evanescent light is generated from the prism surface. Only information can be obtained. When the refractive index of the prism is small (for example, 2.0), since the penetration depth is several μm or more, the depth of the sample outermost surface or a portion immediately below the outermost surface of the sample (this corresponds to the magnetic layer of the magnetic recording medium) Analysis becomes difficult. A prism having a refractive index of 2.0 to 4.5 can be easily obtained, and the outermost surface of the sample and its immediate vicinity can be analyzed with high precision. However, the prism is transparent in the infrared region and has a refractive index of more than 4.5. Is difficult to obtain.

The present invention is configured so as to be able to analyze the organic material inside the medium in addition to the analysis of the lubricant on the outermost surface of the medium. The reason is that the organic material in the recording medium, especially the lubricant, is one of the major factors that affect the reliability of the medium, and even if the amount of the lubricant is the same in the entire medium, the presence of the lubricant in the medium Condition (concentration distribution in the depth direction,
It is known that the reliability greatly differs depending on the concentration on the surface. The present invention has enabled, for the first time, high-precision analysis of organic materials in a medium, which was not possible with the prior art, and in this regard, the present invention has a very important technical meaning.

In the variable angle incident optical system according to the present invention,
Since the optical system is configured with the sample mounting portion and the above-mentioned hemispherical prism separated from each other, only the optical system can be sealed, and operations such as sample replacement can be facilitated. In addition, since the optical system is sealed, carbon dioxide or moisture does not enter the optical path of the optical system when the sample is replaced, so that noise generation due to these can be suppressed and the sample can be replaced. After this, it is not necessary to take extra waiting time for replacing the sample chamber with nitrogen gas or the like for removing these.

[0045]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment First, an optical system constituting an infrared microscope / FT-IR apparatus according to the present invention will be described with reference to FIG. This optical system is housed in a closed sample chamber, that is, a case H, pm1 and pm2 are parabolic mirrors facing each other, and P is a focal point thereof. A hemispherical prism (not shown) is arranged at the focal point P, and a sample is placed on this prism.
mi and mo are an entrance mirror and an exit mirror, respectively. The mirrors m1 and m2 for controlling the degree of incidence angle are arranged on a common movable stage ST so that they can move in parallel with the movable stage. M is a folding mirror, W1, W
Reference numeral 2 denotes an entrance window and an exit window, respectively. Further, in the case H, an opening / closing opening and an opening / closing lid for exchanging a sample are provided above the gap between the parabolic mirrors pm1 and pm2 (not shown).

The operation of the above optical system will be described. The infrared light incident on the case H from the entrance window W1 is incident on the incident mirror mi.
Is guided to the movable mirror m1. m1 is the movable stage ST
Moves in parallel with the optical path, and the incident position on the parabolic mirror pm1 can be changed while keeping the optical path parallel. All light incident on the parabolic mirror pm1 in parallel with the optical axis is incident on the focal point P. At this time, the position of incidence on the parabolic mirror pm1 moves (in FIG. 1, m1, m2 indicated by solid lines).
Moves to m1 and m2 indicated by dotted lines. ), The incident angle to the focal point P changes (the optical path indicated by the solid line changes to the optical path indicated by the dotted line). The light reflected at the focal point P exits from the parabolic mirror pm1 to the opposing parabolic mirror pm2 while maintaining the incident angle on the focal point P. The light emitted from the parabolic mirror pm2 is turned back by the turning mirror M, and the parabolic mirror pm1
The light is guided to the movable mirror m2 in parallel with the incident light. Thus, the operation of the movable stage ST allows the movable mirror m1 and the movable mirror m
By moving 2 in parallel, the angle of incidence on the focal point P (the position where the hemispherical prism is installed) becomes variable.

Further, since the optical system having a variable incident angle is accommodated in the closed case H (sample chamber), outside air can be prevented from entering the optical system due to the sample exchange above the focal point P. Also, sample exchange is easy.

Hereinafter, an embodiment of the present invention in which a floppy disk is used as a sample will be described with reference to the drawings. FIG. 2 is a schematic cross-sectional view showing a main configuration of the infrared microscope / FT-IR apparatus. FIG. 3 is an explanatory diagram showing the configuration of the single beam measuring device. FIG. 4 is a flowchart showing an analysis method by the analyzer of FIG.

The single beam measuring device is connected to the interference light source unit 10.
, A measuring unit 20 and a signal processing unit 30.
The interference light source unit 10 includes an infrared light source 11 and a movable mirror 12.
And a half mirror 13. The measuring section 20 is configured by providing a hemispherical prism 21, an incident angle varying device 22, and a detector 23 in a sample chamber (not shown). The signal processing unit 30 includes a signal amplifier 31, a Fourier transformer 32,
A refractive index calculator 33, a depth information calculator 34, a depth profile calculator 35, a memory 36, and a display 37 are provided, and these are connected in this order.

In the sample chamber, as shown in FIG. 2, the surface to be analyzed of the reference R (control), that is, the surface on the side of the magnetic layer on the surface of the support constituting the floppy disk, is provided with a hemispherical surface made of germanium or silicon. The prism 21 is set on the bottom surface of the prism 21 with an appropriate pressure of 10 kgf / cm ² or less using the contact pressure control device 24 having the above-described configuration. Then, an analysis operation is performed on the reference R in accordance with the flowchart shown in FIG.
Then, instead of the reference R, the sample S is set in the sample chamber in the same manner as described above, and the same analysis operation is performed.

In this case, the contact pressure Ps of the sample S to the prism 21 is set to the contact pressure R in the case of the reference R.
It is important to adjust the same or almost the same as s (to make the absolute value of the difference between Ps and Rs 10 mgf / cm ² or less) in order to enhance the analysis accuracy. Note that the reference R
Is different from sample S only in that no magnetic layer is formed. Hereinafter, the above operation will be described in more detail.

The refractive index of the hemispherical prism 21 is determined in advance by an appropriate means, and the refractive indices of the reference R and the analysis surface of the sample S are measured. For example, to measure the refractive index of the analysis target surface of the sample S,
The sample S is set in the measuring section 20 of FIG. 3 as shown in FIG. 2, and infrared light (wave number range is, for example, 40
The angle of incidence on the hemispherical prism 21 of 0cm ^-1 ~5000cm ^-1) θ (FIG. 2), 0 ° by the incident angle varying device 22
Within an appropriate range within a range of from 90 to 90 (for example, from 30 to 80).
Scan in °). During this time, the information signal unit 30 plots the infrared light absorption intensity of the sample S with respect to the incident angle θ, and the incident angle and the refractive index of the prism when the absorption intensity takes the minimum value (that is, when the light is totally reflected). Thus, the refractive index of the sample S is automatically calculated by the refractive index calculator 33.

Next, qualitative analysis and quantitative analysis of the organic material in the surface layer of the sample S are performed using the apparatus of FIG. 3 according to the flowchart of FIG. To do so, the incident angle θ of the infrared light from the infrared light source 11 to the hemispherical prism 21 is set to 0 ° to 90 ° by the incident angle varying device 22 in the same manner as described above.
Scan within an appropriate range of °. During this time, the reflected light from the sample S (the same is true for the reference R) is processed by the signal amplifier 31 and the Fourier transformer 32 of the signal processing unit 30 to obtain an infrared absorption spectrum. Thus, the depth profile is automatically calculated by the refractive index calculator 33.

[0054] That is the wavelength of the infrared light lambda, the incident angle theta, the refractive index n _P of the hemispherical prism 21 that is determined in advance, by the following [Equation 1] from the refractive index n _S of the sample S, each of the infrared light Penetration depth d (typically 100 nm) of the evanescent wave from the surface of the sample S to the inside at an incident angle of
数 several μm) is calculated.

[0055]

(Equation 1)

Then, from the penetration depth d and the absorption intensity of the infrared absorption spectrum (for example, see FIG. 7 described later), the depth profile calculation unit 34 and the depth profile calculation unit 35 calculate the depth profile. , That is, sample S
The concentration distribution of the organic material in the depth direction of is calculated quantitatively,
The result is recorded in the memory 36 and the display 37
Will be displayed. The qualitative analysis of the organic material is performed by analyzing the obtained infrared absorption spectrum by a conventional method. Further, the same operation as described above is performed for the reference R. Then, the results of the quantitative analysis and the qualitative analysis of the sample S are finally obtained by comparing the analysis result of the sample S with that of the reference R.

Embodiment 2 Another embodiment in which a floppy disk is used as a sample will be described with reference to the drawings. FIG. 5 is an explanatory diagram showing a configuration of an infrared microscopic / FT-IR device using a double beam, and FIG. 6 is a flowchart showing an analysis method by the analyzer of FIG.

The analyzer comprises the interference light source unit 10, the measurement unit 20 for the reference R, the measurement unit 40 for the sample S, the signal processing unit 50, and the signal processing unit 60. The configuration of the interference light source unit 10 is the same as that of the interference light source unit 10 in FIG. The configuration of the measuring units 20 and 40 is the same as that of the measuring unit 20 shown in FIG.
And the same as The measuring units 20 and 40 are connected to the interference light source unit 1
Contact 0 in parallel. The measuring unit 20 is a signal processing unit 50
Then, the measuring unit 40 communicates with the signal processing unit 60 in series.

The signal processing section 50 includes a signal amplifier 51, a Fourier transformer 52, a refractive index calculating section 53, and a depth information calculating section 5.
4 and the depth profile calculation unit 55 are connected in series in this order. The signal processor 60 includes a signal amplifier 61, a Fourier transformer 62, a refractive index calculator 63, and a depth information calculator 6
4. The depth profile calculator 65, the memory 66, and the display 67 are connected in series in this order. Further, the depth profile calculation unit 55 of the signal processing unit 50 is connected to the memory 66 of the signal processing unit 60.

The analyzer of FIG. 3 is configured to analyze the reference R and the sample S by using the common (single) measuring unit 20 and the signal processor 30, whereas the analyzer of FIG. Is configured such that (1) by providing a measuring unit 20 dedicated to the reference R and a measuring unit 40 dedicated to the sample S, the reflected light can be detected in parallel (simultaneously) with respect to the reference R and the sample S. And (2) the reflected light from the reference R by the signal processing unit 50 and the reflected light from the sample S by the signal processing unit 6.
0, and the profile analysis results of the organic material in the depth direction obtained are recorded in a common memory 66 and displayed on a common display unit 67. There is.

The analyzer shown in FIG. 5 can always perform simultaneous measurement for the reference R and the sample S, so that an extremely high-precision analysis result can be obtained.
It is superior to the analyzer of FIG. The procedure of the analysis method using the apparatus shown in FIG. 5 is the same as that in the first embodiment, and thus a specific description is omitted.

[0062]

EXAMPLES Examples of the present invention and comparative examples will be described below. Example 1 A magnetic coating having the following composition was applied on a support to form a magnetic layer, and a back coating having the following composition was applied on the lower surface of the support to form a back coat layer, thereby obtaining a magnetic recording medium. A tape was prototyped.

<Composition of Magnetic Layer Paint> 100 parts by weight of Fe-based metal ferromagnetic powder (coercive force = 160 kA / m, saturation magnetization = 145 Am ² / kg, specific surface area = 51 m ² / g, major axis length = 0 0.08 μm, needle ratio = 3) Polyvinyl chloride resin 14 parts by weight (MR-110 made by Nippon Zeon) Polyester polyurethane resin 3 parts by weight (Toyobo) 5 parts by weight of additive (Al ₂ O ₃ ) Lubricant (heptyl stearate) 0.5 parts by weight Solvent: (1) 150 parts by weight of methyl ethyl ketone (2) 150 parts by weight of cyclohexanone

In the preparation of the magnetic layer coating material, a ferromagnetic powder, a binder (resin), an additive, a lubricant and a solvent were mixed according to a conventional method, kneaded by an extruder, and dispersed by a sand mill for 6 hours. The magnetic layer paint 100 after this dispersion
3 parts by weight of polyisocyanate to 7 parts by weight
m, applied to one side of a PET (polyethylene terephthalate) film to a thickness of 6.5 μm, oriented by a solenoid coil, dried, calendered,
A curing treatment was performed. Further, a back coating having the following composition was applied to the opposite surface of the PET film, and cut into a width of 8 mm to obtain a magnetic tape.

<Composition of back coating> 100 parts by weight of carbon black # 50 100 parts by weight of polyester polyurethane resin (Nipporan N-2304) Solvent: (1) 500 parts by weight of methyl ethyl ketone (2) 500 parts by weight of cyclohexanone

Example 2 A magnetic tape was produced in the same manner as in Example 1 except that the amount of the lubricant was changed to 1 part by weight.

Example 3 A magnetic tape was produced in the same manner as in Example 1 except that the amount of the lubricant was changed to 2 parts by weight.

Example 4 A magnetic tape was produced in the same manner as in Example 1 except that the amount of the lubricant was changed to 3 parts by weight.

With respect to the magnetic tapes manufactured in Examples 1 to 4, the lubricant in the organic thin film (magnetic layer) on the recording medium was qualitatively analyzed by the apparatus shown in FIG. 3 and the content thereof was quantitatively analyzed. In addition, qualitative analysis and quantitative analysis of the lubricant (in the surface layer of the PET film, that is, in the uppermost layer portion of the PET film) in the recording medium were performed by comparing the area intensity of the stretching vibration peak of CH ₂ . 7 to 10 show the infrared absorption spectra obtained in Examples 1 to 4. These figures show the measurement results of the lubricant profile in the thickness direction of the magnetic tape.

In the apparatus shown in FIG. 3, the reference measurement was performed using the magnetic tape containing no lubricant as described above, and then the analysis was performed using the magnetic tape obtained in each of the examples. As a result, an infrared absorption spectrum of only the lubricant can be obtained. Further, since the molecular structure of the lubricant was known before the measurement, the qualitative analysis and the quantitative analysis of the lubricant could be performed by comparing the peak area intensities of the absorption spectrum peculiar to the molecular structure.

Comparative Example 1 The magnetic tape obtained in Example 4 was subjected to high-sensitivity reflection infrared absorption spectroscopy to obtain an absorption spectrum. The results are shown in FIG. As is clear from this figure, unlike the method of the present invention, neither qualitative analysis nor quantitative analysis of the lubricant was possible. It is considered that the cause is that infrared light passes through the sample in the high-sensitivity reflection infrared absorption spectroscopy, so that the influence of light interference is large, and the reflectance of the sample is very small. On the other hand, in the present invention, infrared light only reaches the surface layer of the support from the surface of the magnetic layer.

The graph of FIG. 12 relates to Examples 1 to 4, and shows the result of measuring the lubricant content in the magnetic layer at a specific point on the sample by the apparatus of FIG. It is. In this graph, the horizontal axis indicates the amount of lubricant added to the magnetic layer paint, and the vertical axis indicates the measured value of the lubricant content in the actually formed magnetic layer. Example 1,
The values on the horizontal axis are 0.5, corresponding to 2, 3, and 4, respectively.
In contrast to 1, 2, and 3, the value on the vertical axis is about 0.
5, 3, 60, and 80, and the ratio between the value on the horizontal axis and the value on the vertical axis is almost constant. As is apparent from the spectrum of Comparative Example 1 (FIG. 11), the lubricant content in the magnetic layer could not be measured at all by the high sensitivity reflection absorption method, whereas the result of FIG. measuring device·
It can be seen that the method allows the lubricant content in the magnetic layer to be measured with considerable accuracy.

Examples 5 to 8 In these examples, metal thin film type magnetic tapes were prepared and analyzed by the apparatus shown in FIG. That is, a 10 μm thick P
A 100 nm thick ferromagnetic metal thin film was formed on the ET film by applying a Co-Ni alloy by oblique deposition. Next, a film having a thickness of 15
A carbon film having a thickness of nm was formed, and a solution in which a lubricant (heptyl stearate) was dissolved at various concentrations in toluene was applied onto the film. This film was cut into a width of 8 mm to obtain a sample tape. In this case, the lubricant concentration of the toluene solution of the lubricant was 0.5 wt% in Example 5, 1 wt% in Example 6, 2 wt% in Example 7, and 3 wt% in Example 8. FIG. 13 shows the obtained infrared absorption spectrum.
To FIG.

Comparative Example 2 The sample tape obtained in Example 8 was subjected to high-sensitivity reflection infrared absorption spectroscopy to obtain an absorption spectrum. The results are shown in FIG. As is clear from this figure, neither qualitative analysis nor quantitative analysis of the lubricant was possible.

Embodiment 9 FIG. 18 relates to Embodiment 1. FIG. 18 shows the result of variably measuring the incident angle of the lubricant content in the magnetic layer at a specific point on the sample using the optical system of FIG. It is a graph shown. In this graph, each time the angle of incidence of infrared light is changed, the corresponding methylene and carbonyl absorptions of the lubricant change, which is consistent with the theoretical equation ([Equation 1] above). It can be seen that the depth of the sample corresponds to the change in the incident angle of the infrared light.

The graph of FIG. 19 plots the lubricant amount (relative value) in the sample depth direction based on the measurement result of FIG. In this sample, since the amount of the lubricant is linear with respect to the depth, it can be seen that the lubricant is uniformly distributed in the magnetic layer.

Further, in the above measurement, when the incident angle of the infrared light to the sample is changed, it is not necessary to open and close the sample chamber. Therefore, it is not necessary to replace the sample chamber with nitrogen after changing the incident angle. Only 15 minutes to measure points
Minutes.

Comparative Example 3 When a commercially available optical system (trade name: Seagull: manufactured by Harrick Co.) was used, the sample chamber was replaced with nitrogen for 30 minutes as the incident angle of infrared light changed. Requires
A total measurement time of 3 hours was required.

[0079]

As is apparent from the above description, according to the infrared microscope / FT-IR apparatus according to the present invention or the method for analyzing a recording medium using the same, a magnetic tape, a simple operation and a simple operation can be used. Performs qualitative and quantitative analysis of organic materials, especially organic lubricants, on the surface of high-density recording media such as floppy disks, optical disks, and hard disks (the surface of the medium and the portion immediately below the surface) with high precision and high reproducibility. There is an effect that can be. Such an effect cannot be obtained by conventional high sensitivity reflection absorption infrared absorption spectroscopy or internal reflection infrared spectroscopy.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an optical system of an infrared microscope / FT-IR apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing a main configuration of an infrared microscopic / FT-IR device according to the present invention.

FIG. 3 is an explanatory diagram showing a configuration of a single beam measuring device according to the present invention.

FIG. 4 is a flowchart showing an analysis method by the measuring device of FIG. 3;

FIG. 5 is an explanatory diagram showing a configuration of a double beam measuring device according to the present invention.

FIG. 6 is a flowchart showing an analysis method by the measuring device of FIG.

FIG. 7 is an infrared absorption spectrum obtained in Example 1 of the present invention.

FIG. 8 is an infrared absorption spectrum obtained in Example 2 of the present invention.

FIG. 9 is an infrared absorption spectrum obtained in Example 3 of the present invention.

FIG. 10 is an infrared absorption spectrum obtained in Example 4 of the present invention.

FIG. 11 is an infrared absorption spectrum obtained in Comparative Example 1.

FIG. 12 is a graph collectively showing the analysis results obtained in Examples 1 to 4 of the present invention.

FIG. 13 is an infrared absorption spectrum obtained in Example 5 of the present invention.

FIG. 14 is an infrared absorption spectrum obtained in Example 6 of the present invention.

FIG. 15 is an infrared absorption spectrum obtained in Example 7 of the present invention.

FIG. 16 is an infrared absorption spectrum obtained in Example 8 of the present invention.

FIG. 17 is an infrared absorption spectrum obtained in Comparative Example 2.

FIG. 18 relates to Example 9 of the present invention, and is a graph showing the relationship between the incident angle of infrared light on a sample and the absorbance of a specific functional group.

19 is a graph related to Example 9 of the present invention, in which a lubricant amount (relative value) in a sample depth direction is plotted based on the measurement result of FIG. 18.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Interference light source part, 20 ... Measurement part, 21 ... Hemispherical prism, 22 ... Incident angle variable device, 23 ... Detector, 24
... contact pressure control device, 30 ... signal processing unit, 33 ... refractive index calculation unit, 34 ... depth information calculation unit, 35 ... depth profile calculation unit, 40 ... interference light source unit, 50, 60 ... signal processing unit, H
... Sample chamber (closed case), M: folding mirror, P: focal point, ST: movable stage, W1: entrance window, W2: exit window, m1: movable mirror, m2: movable mirror, mi: entrance mirror, mo
... Outgoing mirror, pm1, pm2 ... Parabolic mirror

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G059 AA01 BB15 CC12 DD13 EE01 EE02 EE10 FF08 HH01 HH06 JJ12 JJ14 JJ30 KK01 MM05 MM10 MM20 PP04

Claims (11)

[Claims] 1. A sample surface portion is obtained by bringing a prism into close contact with a sample surface, making infrared light incident on the prism at a predetermined angle, and analyzing the spectrum of infrared light totally reflected on the sample surface by an FT-IR apparatus. In the infrared microscopic / FT-IR apparatus based on the attenuated total reflection method, which performs the analysis of the above, a hemispherical prism having a flat bottom surface as a prism is provided, and the sample mounting part and the incident optical system are controlled by the hemispherical prism. An infrared microscopic / FT-IR apparatus comprising an optical system having a variable incident angle separated from each other. 2. An infrared microscope / FT-IR apparatus according to claim 1, wherein said variable angle of incidence optical system is housed in a closed sample chamber. 3. An infrared microscope / FT-IR apparatus according to claim 1, wherein said variable-angle incident optical system includes parabolic mirrors facing each other. 4. The infrared micro-FT-IR according to claim 1, further comprising a contact pressure control device for finely adjusting a contact pressure between the bottom surface of the hemispherical prism and the sample surface.
apparatus. 5. A sample surface portion is obtained by closely attaching a prism to a sample surface, making infrared light incident on the prism at a predetermined angle, and analyzing the spectrum of infrared light totally reflected on the sample surface by an FT-IR apparatus. In the infrared microscopic / FT-IR apparatus based on the attenuated total reflection method, which performs the analysis of the above, a hemispherical prism having a smooth bottom surface is provided as a prism, and the hemispherical prism is in close contact with the sample surface. An infrared microscopic / FT-IR device comprising a contact pressure control device for finely adjusting pressure. 6. A recording medium characterized in that at least one of a qualitative analysis and a quantitative analysis of a sample surface portion is performed on the recording medium by using the infrared microscope / FT-IR apparatus according to claim 1 or 5. Analysis method. 7. A recording medium according to claim 6, wherein a magnetic layer is formed on a non-magnetic support by a coating film of a magnetic paint mainly composed of a binder and ferromagnetic powder and containing an organic lubricant. A method for analyzing a recording medium, which is a coating type magnetic recording medium. 8. The thin film metal type magnetic recording medium according to claim 6, wherein the recording medium has a metal thin film formed on a nonmagnetic support and a magnetic layer containing an organic lubricant formed on the metal thin film. A method for analyzing a recording medium, comprising: 9. The thin film metal type according to claim 6, wherein the recording medium has an optical recording layer formed on a nonmagnetic support, and an organic thin film containing an organic lubricant is formed on the surface of the optical recording layer. An analysis method for a recording medium, which is an optical recording medium. 10. The method according to claim 6, wherein the wavelength is 2 μm to 20 μm.
A method for analyzing a recording medium, wherein infrared light of μm is incident. 11. The method according to claim 6, wherein the refractive index is 2.0 to 2.0.
A method for analyzing a recording medium, comprising using the hemispherical prism of 4.5.