JP2000178750A - Production of functionally gradient material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for production a functionally gradient material capable of coating a base material with a functionally gradient thin film whose compsn. continuously changes in the thickness direction of the film and also capable of continuously forming a thin film at a high speed by executing plasma discharge in the vicinity of the atmosphere pressure without needing a high vacuum degree. SOLUTION: At the time of executing discharge plasma treatment in such a manner that, under a pressure near the atmosphere pressure, a base material 5 is arranged between a pair of counter electrodes 3, 4 so as to be continuously moved, and pulselike voltage in which the voltage rising time is <=100 μs, and an electric field intensity is 1 to 100 kV/cm is applied, the electric field intensity between the counter electrodes 3 and 4 is continuously changed along the running direction of the base material 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a functionally gradient material.

[0002]

2. Description of the Related Art A functionally graded material is a material based on a new concept. Functionally graded materials manufactured by using a gas phase synthesis method such as PVD or CVD include electric / magnetic, optical, chemical, biological / medical. Applications are desired in a wide range of fields such as aviation and space. It is known that the functionally graded material is effective as a means for preventing cracks and improving the adhesion to a substrate. Therefore, in recent years, applications to new optical materials by continuously changing the refractive index have been reported.

[0003] With the spread of color displays,
A high resolution is required, and a multi-layer deposited film utilizing light interference or a film coated with a CVD film and provided with an antireflection function has been put to practical use. However, antireflection coatings made of these multi-layer coatings are currently applied only to a limited number of high-grade products due to their high formation costs.
The challenge is to obtain a high-performance antireflection film at low cost.

[0004] For example, a plasma C
In forming a hard coat layer by the VD method, a method of reducing the reflectance over a wide area by continuously lowering the refractive index at a portion in contact with the plastic substrate in the thickness direction (Japanese Unexamined Patent Application Publication No. No. 56002) has been proposed.

[0005]

However, the above method requires a high degree of vacuum when forming the hard coat layer by the plasma CVD method, and thus the hard coat layer is continuously formed on the surface of the substrate. However, it is difficult to perform mass production, and the processing speed is slow.

[0006] The present invention solves the above-mentioned problems, and can coat a substrate with a functionally graded thin film whose composition continuously changes in the thickness direction of the film, does not require a high degree of vacuum, and is close to atmospheric pressure. It is an object of the present invention to provide a method for producing a functionally graded material, which can form a thin film continuously at high speed by performing a plasma discharge at a temperature.

[0007]

The method for producing a functionally graded material according to the invention described in claim 1 (hereinafter referred to as "the present invention") comprises:
At a pressure close to the atmospheric pressure, the substrate is disposed so as to continuously move between the pair of opposed electrodes, a reaction gas is introduced between the opposed electrodes, the voltage rise time is 100 μs or less, and the electric field strength is reduced. When a pulsed voltage of 1 to 100 kV / cm is applied to perform the discharge plasma treatment, the electric field strength between the opposing electrodes is continuously changed along the traveling direction of the substrate.

In the present invention, as a method of continuously changing the electric field strength between the opposed electrodes, the distance between the opposed electrodes is set along the running direction of the substrate.
Continuously changing method A method of arranging a solid dielectric whose thickness or composition continuously changes along the running direction of the base material on at least one of the opposing surfaces of the opposing electrode is exemplified.

In the present invention, at least two kinds of reactive gases may be introduced between the opposing electrodes so that the mixing ratio changes continuously along the running direction of the substrate. . In this case, a method is used in which one reactive gas is introduced from the inlet side of the base material between the opposed electrodes, and the other reactive gas is introduced from the outlet side of the base material between the opposed electrodes.

In the present invention, the term “under a pressure near the atmospheric pressure” refers to
Refers to a pressure of 100 to 800 Torr. The pressure is preferably in the range of 700 to 780 Torr, which facilitates pressure adjustment and makes the apparatus simple.

In the present invention, examples of the pair of opposed electrodes include those made of a simple metal such as copper and aluminum, alloys such as stainless steel and brass, and intermetallic compounds.
Examples of the electrode structure of the counter electrode include a parallel plate type (excluding the invention described in claim 2), a non-parallel plate type, a cylindrical counter plate type, a ball counter plate type, a hyperboloid counter plate type, and a coaxial cylindrical type structure. No.

In the invention according to claim 2, the distance between the electrodes is changed in order to continuously change the electric field strength between the opposed electrodes along the traveling direction of the substrate. The distance between the electrodes is determined in consideration of the thickness of the solid dielectric, the magnitude of the applied voltage, the purpose of utilizing plasma, and the like.
It is preferably 0 mm. If it is less than 1 mm, it is not enough to place the electrodes at intervals. If it exceeds 50 mm, it is difficult to generate uniform discharge plasma.

In the present invention, this is usually performed in a device in which a solid dielectric is provided on at least one of the opposing surfaces of the electrode. In this case, the portion where the plasma is generated is located between the solid dielectric and the electrode when a solid dielectric is provided on one of the electrodes, and between the solid dielectrics when the solid dielectric is provided on both of the electrodes. The space between them.

Examples of the material of the solid dielectric include plastics such as polytetrafluoroethylene and polyethylene terephthalate, glass, metal oxides such as silicon dioxide, aluminum oxide, zirconium dioxide and titanium dioxide, and double oxides such as barium titanate. And the like.

According to the third aspect of the present invention, in order to continuously change the electric field strength between the opposing electrodes along the traveling direction of the base material, at least one of the opposing surfaces of the opposing electrodes has:
A solid dielectric whose thickness or composition continuously changes along the running direction of the substrate is arranged.

In the present invention, in the glow discharge under a pressure close to the atmospheric pressure, the present inventor has found that the discharge current density reflects the plasma density and is a value that affects the surface treatment effect as shown below. Have been clarified by their research,
The discharge current density between the electrodes is 0.2 to 300 mA /
When the thickness is in the range of cm ² , uniform discharge plasma can be generated, and good surface treatment can be performed.

In the surface treatment, any treatment can be performed by selecting a gas (hereinafter, referred to as a reaction gas) existing in the discharge plasma generation space.

As the reaction gas, a metal-containing gas can be suitably used. Examples of the metal include Al, As, and B.
i, B, Ca, Cd, Cr, Co, Cu, Ga, Ge,
Au, In, Ir, Hf, Fe, Pb, Li, Na, M
g, Mn, Hg, Mo, Ni, P, Pt, Po, Rh,
Sb, Se, Si, Sn, Ta, Te, Ti, V, W,
Examples of the metal include Y, Zn, and Zr, and examples of the gas containing the metal include a reaction gas such as a metal organic compound, a metal-halogen compound, a metal-hydrogen compound, a metal-halogen compound, and a metal alkoxide. These may be used alone or in combination of two or more.

When the metal is Si, for example, tetramethylsilane [Si (CH ₃ ) ₄ ], dimethylsilane [S
i (CH ₃ ) ₂ H ₂ ], tetraethylsilane [Si (C ₂ H ₅ )
₄ ] and the like; metal halide compounds such as silicon tetrafluoride (SiF ₄ ), silicon chloride (SiCl ₄ ) and silicon chloride (SiH ₂ Cl ₂ ); monosilane (SiH ₄ ), disilane (SiH ₃ ) SiH ₃ ), trisilane (SiH ₃ SiH ₂ Si)
H ₃ ) and other metal hydrogen compounds; tetramethoxysilane [Si
(OCH ₃ ) ₄ ], tetraethoxysilane [Si (OC
₂ H ₅ ) ₄ ], triethoxymethylsilane [SiCH ₃ (OC ₂
H ₅ )] and the like. These may be used alone or in combination of two or more.

When the metal is Ti, for example, tetramethyl titanium [Ti (CH ₃ ) ₄ ], dimethyl titanium [T
i (CH ₃ ) ₂ H ₂ ], tetraethyl titanium [Ti (C ₂ H ₅ )
_4] an organometallic compound such as; 4 silicon fluoride (TiF _4), 4 silicon tetrachloride (TiCl _4), metal halide compounds such as 2 silicon tetrachloride (TiH ₂ Cl _2); Mono titanium (TiH _4), Jichitan (TiH ₃ TiH ₃ ), trititanium (TiH ₃ TiH ₂ Ti)
H ₃₎ metal hydride such as; tetramethoxy titanium [Ti
(OCH ₃ ) ₄ ], tetraisopropoxy titanium [Ti (O
CH ₃ CHCH ₃ ) ₄ ]. These may be used alone or in combination of two or more. Among the above-mentioned metal-containing gases, in consideration of safety, it is preferable that there is no danger of ignition or explosion in the atmosphere, such as metal alkoxides and metal halides, at normal temperature and in the air. Thus, metal alkoxides are preferably used.

If the metal-containing gas is a gas, it can be introduced into the discharge space as it is. If it is liquid or solid, it can be introduced into the discharge space via a vaporizer.
By using such a reaction gas, SiO ₂ , Ti
By forming a thin film of a metal oxide such as O ₂ or SnO ₂ , electrical and optical functions can be imparted to the substrate surface.

When a metal alkoxide is used as a reaction gas, it is preferable to add an oxygen gas in order to form a dense metal oxide thin film having a small amount of organic components. In this case, the oxygen gas is a metal alkoxide of 10%.
It is preferably at least volume%.

Further, by using a fluorine-containing compound gas as the above-mentioned reaction gas, a fluorine-containing polymer film can be formed on the surface of the substrate to lower the surface energy and obtain a water-repellent surface.

Further, by performing the treatment in an atmosphere of a monomer having a hydrophilic group and a polymerizable unsaturated bond in the molecule, a hydrophilic polymer film can be deposited.

As described above, a compound having more electrons is more advantageous as the atmospheric gas (reactive gas) in increasing the plasma density and performing high-speed processing. However, argon or nitrogen is preferred in that it is easily available and inexpensive.

Further, from the viewpoint of economy and safety, it is preferable to carry out the treatment in an atmosphere in which the reaction gas is diluted with an inert gas. Examples of the inert gas include rare gases such as helium gas, neon gas, argon gas, and xenon gas, and nitrogen gas. These may be used alone or in combination of two or more.

When a diluent gas is used, the ratio of the reaction gas is preferably 0.01 to 10% by volume.

As described above, a compound having more electrons is more advantageous as an atmospheric gas in increasing the plasma density and performing high-speed processing. Therefore, the most desirable choice in consideration of availability, economy, processing speed,
This is an atmosphere containing argon or nitrogen as a diluent gas.

In the present invention, at least two types of reactive gases are opposed between the opposed electrodes so that the mixing ratio thereof changes continuously along the running direction of the substrate. It is introduced between the electrodes.

The substrate used in the present invention includes
Examples thereof include plastics such as polyethylene, polypropylene, polystyrene, polycarbonate, polyethylene terephthalate, polytetrafluoroethylene, and acrylic resin, glass, ceramic, and metal. Examples of the shape of the substrate include a plate shape and a film shape, but are not particularly limited thereto. According to the surface treatment method of the present invention, it is possible to easily cope with the treatment of substrates having various shapes.

In the present invention, the electric field applied between the electrodes is pulsed, the voltage rise time is 100 μs or less, and the electric field intensity is 1 to 100 kV / cm.

FIG. 1 shows an example of a pulse voltage waveform. Waveforms (A) and (B) are impulse waveforms, waveform (C) is a square wave waveform, and waveform (D) is a modulation waveform. Although FIG. 1 shows an example in which voltage application is repeated positive and negative, a so-called one-sided waveform in which a voltage is applied to either the positive or negative polarity side may be used.

The pulse voltage waveform in the present invention is not limited to the above-mentioned waveform, but the shorter the rise time of the pulse, the more efficiently the gas is ionized during the generation of plasma. If the rise time of the pulse exceeds 100 μs, the discharge state easily shifts to an arc and becomes unstable, so that a high-density plasma state due to a pulse electric field cannot be expected. Further, it is better that the rise time is short. However, there is a limit to a device that has an electric field intensity large enough to generate plasma at normal pressure and generates a short rise time electric field. It is difficult to achieve a pulsed electric field with a rise time of less than. More preferably, the rise time is 50 ns to 5 μs. Here, the rise time refers to a time during which the voltage change is continuously positive.

It is preferable that the fall time of the pulse electric field is also steep.
It is preferable that the time scale is less than μs. For example, in the power supply device used in the embodiment of the present invention, the rise time and the fall time can be set to the same time, although it differs depending on the pulse electric field generation technique.

Further, modulation may be performed using pulses having different pulse waveforms, rise times, and frequencies.

The frequency of the pulse electric field is 0.5 kHz to 1
Preferably, it is 00 kHz. If the frequency is less than 0.5 kHz, the plasma density is low, so that it takes too much time for the treatment. If the frequency exceeds 100 kHz, arc discharge is likely to occur. More preferably, the frequency is 1 kHz or more. By applying such a high-frequency pulsed electric field, the processing speed can be greatly improved.

The pulse duration in the pulse electric field is preferably 1 to 1000 μs. 1μ
s, the discharge becomes unstable, and
If it exceeds s, it is easy to shift to arc discharge. More preferably, it is 3 μs to 200 μs. Here, one pulse duration is an example shown in FIG.
It refers to the time during which a pulse is continuous in a pulse electric field composed of N and OFF repetitions. In the case of the intermittent pulse as shown in FIG. 2A, the pulse duration is equal to the pulse width time, but in the case of the pulse having the waveform as shown in FIG. Means time including

Further, in order to stabilize the discharge, it is preferable to have an OFF time lasting at least 1 μs within a discharge time of 1 ms.

The above discharge is performed by applying a voltage.
Although the magnitude of the voltage is appropriately determined, in the present invention,
The electric field strength between the electrodes is set in a range of 1 to 100 kV / cm. If it is less than 1 kV / cm, it takes too much time for the treatment, and if it exceeds 100 kV / cm, arc discharge is likely to occur. In applying the pulse voltage, a direct current may be superimposed.

FIG. 3 shows a block diagram of a power supply when such a pulsed electric field is applied. FIG. 4 shows an equivalent circuit diagram of the power supply. In FIG. 4, SW is a semiconductor element functioning as a switch. By using a semiconductor element having a turn-on time and a turn-off time of 500 ns or less as the switch, the electric field strength as described above is 1 to 100 kV / cm, and the rise time and fall time of the pulse are 100 μs or less. Such a high voltage and high speed pulsed electric field can be realized.

Hereinafter, the principle of the power supply will be briefly described with reference to the equivalent circuit diagram of FIG. + E is a positive DC voltage supply unit, and -E is a negative DC voltage supply unit. SW1
Reference numerals 4 to 4 denote switch elements composed of the high-speed semiconductor elements as described above. D1 to D4 indicate diodes. I _{1 to} I ₄ indicate the direction of current flow.

[0042] First, when turned ON SW1, load of the positive polarity is charged in the flow direction current I _1. Then, the SW1 is turned OFF, by turning ON the SW2 instantaneously, the electric charge charged is charged in the direction of I ₃ through SW2 and D4. Next, when the switch SW3 is turned on after the switch SW2 is turned off, the load having the negative polarity causes the current I ₂
Charge in the direction of flow. Next, the SW3 is turned OFF, by turning ON the SW4 instantaneously, the electric charge charged is charged in the direction of I ₄ through SW4 and D2. By repeating the above series of operations, the output pulse of FIG. 5 can be obtained.

The advantages of this circuit are that even if the load impedance is high, the charged electric charge can be reliably discharged by operating SW2 and D4 or SW4 and D2, and high speed High-speed charging can be performed using SW1 and SW3, which are turn-on switch elements. Therefore, a pulse signal having a very fast rise time and fall time as shown in FIG. 5 can be obtained.

In the present invention, the applied voltage or the pulse frequency is continuously changed during the plasma processing time to be described later. In this case, the power supply voltage + E, -E is continuously changed during the processing time, so that the applied voltage or the pulse frequency is changed. The pulse frequency can be continuously changed by continuously changing the time for repeating the above series of operations.

In this case, only the applied voltage or only the pulse frequency may be changed continuously, or both the applied voltage and the pulse frequency may be changed continuously.

In the discharge obtained by the above method,
The discharge current density between the counter electrodes is 0.2 to 300 mA / c.
m ² is preferred.

The discharge current density refers to a value obtained by dividing the value of the current flowing between the electrodes by the discharge by the area of the discharge space in the direction orthogonal to the current flow direction, and a parallel plate type electrode is used. In this case, it corresponds to a value obtained by dividing the current value by the facing area. In the present invention, a pulse-shaped current flows to form a pulsed electric field between the electrodes. In this case, the maximum value of the pulse current, that is, the peak-peak value is divided by the above area.

(Function) In the method for producing a functionally graded material of the present invention, a substrate is disposed between a pair of opposing electrodes so as to be continuously moved under a pressure close to the atmospheric pressure, and between the opposing electrodes. The reaction gas is introduced and the voltage rise time is 100μ.
When a pulse-like voltage having an electric field strength of 1 to 100 kV / cm is applied to perform the discharge plasma treatment, the electric field strength between the opposed electrodes is continuously changed along the traveling direction of the base material. As a result, a thin film having a different film quality in the thickness direction is formed on the surface of the base material, and the film itself does not have a clear interface with the base material, and there is no stress concentration at the time of film formation. It is possible to obtain a functionally graded material having excellent adhesion to a thin film and having no clear interface in the film itself.

[0049]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 6 is a schematic sectional view showing an example of an apparatus for producing the functionally gradient material of the present invention cited in claim 2.

As shown in FIG. 6, the apparatus for producing a functionally graded material according to the present invention is provided with a pair of counter electrodes 3 and 4 in a container 2. It is electrically connected, the lower electrode 4 is grounded, and a pulse voltage is applied between the upper electrode 3 and the lower electrode 4. Solid dielectrics 32 and 42 are provided on opposite surfaces of the counter electrodes 3 and 4, respectively.
The distance between 2 and 42 is d1 in the running direction of the substrate 5.
Ｄd2. The base material 5 is introduced from the feeding roll 9 onto the solid dielectric 42 of the lower electrode 4.

On the other hand, a reaction gas introduction unit 6 is provided on the inlet side of the opposing electrodes 3, 4, and from the reaction gas supply unit 7 via the flow control unit 8, the reaction gas introduction unit 6
The reaction gas is continuously supplied between the solid dielectric 32 on the surface and the substrate 5. The substrate 5 travels in the plasma generated by applying a pulse voltage to the reaction gas, and a functionally graded thin film is formed on the surface of the substrate 5,
It is taken up by a take-up roll 92. In addition, seal mechanisms 10 are provided at the inlet and outlet of the base material 5 of the container 2, respectively, so that the base material 5 blocks the atmosphere that is caught in the container 2.

FIG. 7 is a schematic sectional view showing an example of an apparatus for producing the functionally gradient material of the present invention cited in claim 3.

As shown in FIG. 7, the apparatus for producing a functionally graded material of the present invention is provided with a pair of counter electrodes 13 and 14 in a container 12, and the upper electrode 13 is connected to a pulse power supply 11. It is electrically connected, the lower electrode 14 is grounded, and a pulse voltage is applied between the upper electrode 13 and the lower electrode 14. Solid dielectrics 132 and 142 are provided on opposite surfaces of the counter electrodes 13 and 14, respectively.
In the traveling direction of No. 5, the state changes as shown in FIG. Further, the distance between the solid dielectrics 132 and 142 changes continuously (d5 to d6) in the running direction of the base material 15, and the base material 15 is moved from the feeding roll 19 to the solid dielectric of the lower electrode 14. Introduced on body 142.

On the other hand, on the entrance side of the opposing electrodes 13 and 14,
A reaction gas introduction unit 16 is provided, and a reaction gas is supplied between the solid dielectric 132 of the upper electrode 13 and the base material 15 from the reaction gas introduction unit 16 via the flow rate control unit 18 from the reaction gas supply unit 17. It is made to supply continuously. The substrate 15 travels in a plasma generated by applying a pulse voltage to the reaction gas, a functionally graded thin film is formed on the surface of the substrate 15, and is wound up by a winding roll 192. In addition, seal mechanisms 110 are provided at the inlet and outlet of the base material 15 of the container 12, respectively, so that the air drawn into the container 12 by the base material 15 is blocked.

FIG. 9 is a schematic sectional view showing an example of an apparatus for producing the functionally gradient material of the present invention cited in claim 3.

As shown in FIG. 9, the apparatus for producing a functionally graded material of the present invention is provided with a pair of opposed electrodes 23 and 24 in a container 22. It is electrically connected, the lower electrode 24 is grounded, and a pulse voltage is applied between the upper electrode 23 and the lower electrode 24. Solid dielectrics 232 and 242 are provided on opposite surfaces of the counter electrodes 23 and 24, respectively.
5 is constant (d3 = d4) in the traveling direction, and the base material 25 is moved from the feeding roll 29 to the lower electrode 2.
4 on the solid dielectric 242.

On the other hand, reaction gas introduction portions 26, 26 are provided on the inlet side and the outlet side of the counter electrodes 23, 24, and the reaction gases are supplied from the reaction gas supply portions 27, 27 via flow rate control portions 28, 28. Two kinds of reaction gases are continuously supplied between the solid dielectric 232 of the upper electrode 23 and the base material 25 from the gas introduction portions 26, 26. The base material 25
Is driven in a plasma generated by applying a pulse voltage to the reaction gas, a functionally graded thin film is formed on the surface of the base material 25, and is taken up by a take-up roll 292. The seal mechanism 2 is provided at the inlet and outlet of the substrate 25 of the container 22.
10 are provided, respectively, and block the atmosphere trapped in the container 22 by the base material 25.

[0058]

EXAMPLES The present invention will be described in more detail with reference to Examples. In the following embodiments, the semiconductor devices (IXY) are used as the pulse power supplies 1, 11, 21 according to the equivalent circuit diagram of FIG.
A power supply manufactured by Heiden Laboratories, Inc. using a model number “TO-247AD” manufactured by S Company was used.

(Example 1) In the apparatus shown in FIG.
Upper electrode 3 and lower electrode 4 (SUS304, width 350m)
m, a length of 100 mm, and a thickness of 20 mm), a sprayed film of zirconium containing 8% by weight of yttrium oxide as a solid dielectric (dielectric constant 16, film thickness 500)
μm) was used. Upper electrode 3
The distance between the lower electrode 4 and the entrance side d1 = 3 mm, and the exit side d2
= 1 mm, and a 5 μm polyfunctional acrylic hard coat agent (manufactured by Dainichi Seika Co., Ltd., product number “EXF-3”) as the substrate 5
7 ”), a 80 μm-thick triacetylcellulose having a film formed thereon was fed out and disposed from the roll 9 to the take-up roll 92 via the solid dielectric 42 of the lower electrode 4.

Next, after the inside of the container 2 is evacuated to 1 Torr by an oil rotary pump (not shown), argon gas is introduced until the pressure reaches 760 Torr. The reaction gas was supplied from the reaction gas supply unit 7 via the flow rate control unit 8 while diluting with 3 SLM argon gas so that the tetraethyl orthosilicate became 0.5% by volume. It was supplied between the dielectric 32 and the substrate 5.

Next, the rising speed between the upper electrode 3 and the lower electrode 4 is 1 μs, the frequency is 8 kHz, and the applied voltage is ± 3 kV.
Was applied from the pulse power supply 1 to generate discharge plasma.

As described above, 1000 ° on the substrate 5
A functionally graded material on which a thin film was formed was obtained.

The refractive index of the surface of the thin film of the obtained functionally graded material was measured by an ellipsometer (manufactured by Mizojiri Optical Co., Ltd.) and found to be 1.46. Further, the thin film was etched in 200 ° by discharging in an argon gas, and the refractive index was measured. As a result, 1.45, 1.43, 1.42,.
41, indicating that the refractive index changed in the film thickness direction and the film quality changed.

(Embodiment 2) In the apparatus shown in FIG.
Upper electrode 13 and lower electrode 14 (made of SUS304, width 35)
0 mm, a length of 100 mm, and a thickness of 20 mm), from the entrance side to the exit side of the base material 15, as solid dielectrics 132 and 142, titanium silicon oxide (dielectric constant 65) and silicon oxide (dielectric constant) Dielectric constant 5.5) was used in which a gradient composition (film thickness 500 μm) as shown in FIG. 8 was tightly formed. The distance between the upper electrode 3 and the lower electrode 4 was set such that the inlet side d3 = the outlet side d4 = 2 mm.
m multifunctional acrylic hard coat agent (manufactured by Dainichi Seika Co., Ltd.
Roll 1 of 80 μm-thick triacetylcellulose on which a film made of product number “EXF-37” is formed
9 through the solid dielectric 142 of the lower electrode 14,
The winding roll 192 was provided.

Next, after the inside of the container 12 is evacuated to 1 Torr by an oil rotary pump (not shown), argon gas is introduced until the pressure reaches 760 Torr, and the substrate 15 is taken up by the take-up roll 192 at a transport speed of 1 m / min. min from the reaction gas supply unit 17 so that the tetraisopropoxy titanate becomes 0.2% by volume.
8 while diluting with 3 SLM of argon gas
From the reaction gas inlet 16, the solid dielectric 132 and the substrate 15
And between.

Next, the rising speed between the upper electrode 13 and the lower electrode 14 is 1 μs, the frequency is 4 kHz, and the applied voltage is ± 3.
A pulse voltage of kV was applied from the pulse power supply 11 to generate discharge plasma.

As described above, 800 ° on the substrate 15
A functionally graded material on which a thin film was formed was obtained.

The refractive index of the surface of the thin film of the obtained functionally graded material was measured by an ellipsometer (manufactured by Mizojiri Optical Co., Ltd.) and found to be 1.73. Further, the thin film was etched by 200 ° each, and the refractive index was measured. As a result, 1.75, 1.81,
1.89, indicating that the refractive index changed in the film thickness direction and the film quality changed.

(Embodiment 3) In the apparatus shown in FIG.
Upper electrode 23 and lower electrode 24 (made of SUS304, width 35)
0 mm, a length of 100 mm, and a thickness of 20 mm), a sprayed film of zirconium containing 8% by weight of yttrium oxide as a solid dielectric (relative dielectric constant 16, film thickness 5)
(00 μm) was used. The distance between the upper electrode 23 and the lower electrode 24 is d5 = 1 mm on the inlet side and d6 = 3 mm on the outlet side, and a 5 μm polyfunctional acrylic hard coat agent (Dainichi Seika Co., Ltd .;
F-37 ") and a 80-μm-thick triacetyl cellulose having a film formed thereon was fed from the roll 29 to the take-up roll 292 via the solid dielectric 242 of the lower electrode 24.

Next, the inside of the container 22 is evacuated to 1 Torr by an oil rotary pump (not shown), and then argon gas is introduced until the pressure reaches 760 Torr. min from the reaction gas supply unit 27 to the flow control unit 2 so that the tetraisopropoxy titanate becomes 0.5% by volume.
8 while diluting with 3 SLM of argon gas
From the reaction gas introduction part 26, the solid dielectric 232 and the substrate 25
And supplied from the inlet side. On the other hand, 3SLM is supplied from the reaction gas supply unit 272 via the flow rate control unit 282 so that tetraethyl orthosilicate becomes 0.5% by volume.
While diluting with argon gas, the reaction gas introduction unit 262
From the outlet side between the solid dielectric 232 and the substrate 25.

Next, a rising speed of 1 μs, a frequency of 8 kHz and an applied voltage of ± 3 between the upper electrode 23 and the lower electrode 24.
A pulse voltage of kV was applied from the pulse power supply 21 to generate discharge plasma.

As described above, 1000
A functionally graded material on which the thin film of Å was formed was obtained.

FIG. 10 shows the result of composition analysis of the obtained functionally graded material from the thin film surface to the substrate by Auger electron spectroscopy.
It was shown to. From this result, the thin film surface side to the substrate side, it was found that continuously changes from SiO ₂ to TiO _2.

On the other hand, the refractive index of the surface of the thin film measured by an ellipsometer (manufactured by Mizojiri Optical Co., Ltd.) was 1.30.
Further, the thin film was etched by 200 ° each, and the refractive index was measured. As a result, 1.45, 1.71, 1.93, and 2.09 from the thin film surface side toward the substrate, respectively.
It was found that the refractive index changed in the film thickness direction and the film quality changed.

[0075]

The method for producing a functionally graded material of the present invention is configured as described above, so that a substrate can be coated with a functionally graded thin film whose composition continuously changes in the thickness direction of the film, and By performing plasma discharge near the atmospheric pressure without requiring a high degree of vacuum, a thin film can be formed continuously at high speed.

[Brief description of the drawings]

FIG. 1 is a voltage waveform diagram showing an example of a pulse electric field.

FIG. 2 is an explanatory diagram of a pulse duration time.

FIG. 3 is a block diagram of a power supply that generates a pulse electric field.

FIG. 4 is an equivalent circuit diagram of a power supply that generates a pulse electric field.

FIG. 5 is a diagram of an output pulse signal corresponding to an operation table of a pulse electric field.

FIG. 6 is a schematic cross-sectional view showing one example of an apparatus for producing the functionally gradient material of the present invention cited in claim 2.

FIG. 7 is a schematic sectional view showing an example of an apparatus for producing the functionally gradient material of the present invention cited in claim 3.

FIG. 8 is a graph showing a composition distribution in a film thickness direction of a solid dielectric used in Example 2.

FIG. 9 is a schematic sectional view showing an example of an apparatus for producing the functionally gradient material of the present invention, cited in claim 4.

FIG. 10 is a graph showing the results of a composition analysis of the functionally gradient material obtained in Example 3 from the thin film surface to the substrate by Auger electron spectroscopy.

[Explanation of symbols]

 1, 11, 21 Pulse power supply 2, 12, 22 Container 3, 13, 23 Upper electrode 32, 132, 232 Solid dielectric 4, 14, 24 Lower electrode 42, 142, 242 Solid dielectric 5, 15, 25 Base material 6, 16, 26 Reaction gas introduction unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2K009 AA02 BB01 BB11 BB28 CC03 CC14 CC42 CC45 DD04 EE00 FF01 4K030 AA11 BA44 BA46 CA07 CA12 EA03 FA01 GA04 GA14 JA08 KA30

Claims (4)

[Claims] 1. A substrate is disposed between a pair of opposed electrodes so as to continuously move under a pressure close to the atmospheric pressure, a reaction gas is introduced between the opposed electrodes, and a voltage rise time is 100 μs. Hereinafter, when performing a discharge plasma treatment by applying a pulsed voltage having an electric field intensity of 1 to 100 kV / cm, the electric field intensity between the opposed electrodes is continuously changed along the traveling direction of the substrate. A method for producing a functionally graded material, characterized in that: 2. The tilt function according to claim 1, wherein the electric field intensity is continuously changed by continuously changing the distance between the opposed electrodes along the running direction of the base material. Material manufacturing method. 3. An electric field intensity is continuously changed by disposing a solid dielectric whose thickness or composition continuously changes along a running direction of a substrate on at least one of the opposing surfaces of the opposing electrode. The method for producing a functionally gradient material according to claim 1, wherein: 4. The method according to claim 1, wherein at least two kinds of reactive gases are introduced between the opposed electrodes so that a mixing ratio thereof changes continuously along the running direction of the substrate. Item 4. The method for producing a functionally graded material according to any one of Items 1 to 3.