JP2006302747A - Reflection preventive film for field emission display, and field emission display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflection preventive film for FED having a high transmittance throughout the whole visible light range and suppressing migration of alkali metal ion such as Na<SP>+</SP>or the like in the face plate of a field emission display, and having a high productivity and an FED device which has good visibility and in which migration of alkali metal ion such as Na<SP>+</SP>or the like in the face plate is suppressed. <P>SOLUTION: The reflection preventive film 1 for FED has a reflection preventive layer 20 on one face of a substrate 10 and a conductive layer 30 on the other face. The surface resistance value of the conductive layer 30 is 10<SP>4</SP>-10<SP>11</SP>Ω/sq. and luminous transmittance of the reflection preventive film 1 for FED is 90% or more. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an antireflection film for a field emission display and a field emission display device.

  As a next-generation thin display device, a field emission display (hereinafter referred to as FED) has been attracting attention. The FED is formed on a glass element substrate, a glass face plate disposed away from the element substrate, a plurality of electron guns disposed on an inner surface of the element substrate, and an inner surface of the face plate. It consists of a phosphor layer and a metal back. The electron beam output from the electron gun is irradiated onto a metal back to which a high voltage is applied, and excites the phosphor to emit light. An image is displayed on the outer surface of the face plate by the light emission of the phosphor.

In the FED, it is known that when a high voltage is applied to the metal back on the inner surface of the face plate, alkali metal ions such as Na ⁺ in the glass move from the inner surface to the outer surface of the face plate (migration). ing. Then, when alkali metal ions such as Na ⁺ are deposited on the outer surface of the face plate, (i) the outer surface of the face plate is roughened. (Ii) The deposited Na ⁺ reacts with moisture in the air to form water. A problem arises in that it becomes an oxide, and the outer surface of the face plate is eroded, resulting in white turbidity.

  In order to solve this problem, it has been proposed to provide a conductive layer made of a conductive material called a potential regulating layer on a protective plate provided on the outer surface of the face plate (paragraph [0117] to Patent Document 1). [0130]). The protective plate is provided with an antistatic layer having antireflection and antistatic functions on one surface of a substrate, and a conductive layer made of a carbon paste having a plurality of openings on the other surface of the substrate. Is provided.

However, recently, there is an increasing demand for (i) further improving the transmittance of the protective plate over the entire visible light region, and (ii) further improving the productivity of the protective plate.
JP 2000-235837 A

In order to meet these requirements, it is conceivable to provide a transparent metal oxide layer such as In ₂ O ₃ —SnO ₂ (ITO) instead of the carbon paste. However, normal ITO has low resistance (chemical resistance) to the adhesive used to attach the protective plate to the face plate, so the resistance value changes when the transparent metal oxide layer is attacked by the adhesive. As a result, the function as the potential regulating layer cannot be satisfied, and there is a problem that migration of alkali metal ions such as Na ⁺ cannot be suppressed.

Accordingly, an object of the present invention is to provide an antireflection film for FED that has high transmittance over the entire visible light region, suppresses migration of alkali metal ions such as Na ^{+ in} the faceplate of the FED, and has high productivity. An object of the present invention is to provide an FED apparatus in which migration of alkali metal ions such as Na ⁺ in the face plate is suppressed.

The antireflection film for FED of the present invention is an antireflection film for FED in which an antireflection layer is provided on one surface of a substrate and a conductive layer is provided on the other surface, and the surface resistance value of the conductive layer is Is 10 ⁴ to 10 ¹¹ Ω / □, and the luminous transmittance of the antireflection film is 90% or more.
The conductive layer is composed of SnO ₂ and In ₂ O ₃ and contains 30 to 50 atomic percent of Sn in total (100 atomic percent) of Sn and In, or Ga ₂ O ₃ and In ₂ O. ₃ and SnO ₂ , Ga is contained in 2 to 15 atomic% in the total of Ga, In and Sn (100 atomic%), and In is in the total (100 atomic%) of Ga, In and Sn. A layer containing 2 to 15 atomic% is preferable.

The antireflection layer has, in order from the substrate side, a first oxide layer having a refractive index of 1.7 to 2.2 and a surface resistance value of 10 ⁴ to 10 ¹¹ Ω / □, and a refractive index. A second oxide layer having a refractive index of 1.6 or less, a second oxide layer having a refractive index of 1.6 or less, a second oxide layer having a refractive index of 1.6 or less, a third oxide layer containing 90% by mass or more of a mixture of In ₂ O ₃ and CeO ₂ A layer composed of an oxide layer is preferable.
The FED device of the present invention has an FED main body and the antireflection film for FED of the present invention directly attached to the viewing side of the FED main body.

The antireflection film for FED of the present invention has high transmittance over the entire visible light region, suppresses migration of alkali metal ions such as Na ^{+ in} the face plate of the FED, and has good productivity.
The FED apparatus of the present invention has good visibility and suppresses migration of alkali metal ions such as Na ⁺ in the face plate.

<Antireflection film for FED>
FIG. 1 is a schematic cross-sectional view showing an example of the antireflection film for FED of the present invention. The antireflection film 1 for FED includes a base material 10, a transparent antireflection layer 20 provided on one surface of the base material 10, and a transparent conductive layer 30 provided on the other surface of the base material 10. And an adhesive layer 40 provided on the conductive layer 30.
The luminous transmittance of the antireflection film 1 for FED needs to be 90% or more, and thereby has excellent visible light transmittance. The luminous transmittance in the present invention is measured in accordance with JIS Z 8701.

(Base material)
The substrate 10 may be a plastic film that is smooth and can transmit light having a wavelength in the visible light region.
Examples of the plastic include polyethylene terephthalate, polycarbonate, triacetyl cellulose, polyether sulfone, and polymethyl methacrylate.
The thickness of the base material 10 is suitably selected according to a use, and 50-200 micrometers is preferable. The base material 10 may be composed of a single layer or may be a laminate composed of a plurality of layers.

(Antireflection layer)
As the antireflection layer in the present invention, conventionally known antireflection layers can be applied as necessary. The antireflection layer 20 includes a first oxide layer 21, a second oxide layer 22, a third oxide layer 23, and a fourth oxide layer 24 from the substrate 10 side. A layer having both antistatic and antireflection functions is preferred.

The first oxide layer 21 may be a layer having a refractive index of 1.7 to 2.2 and a surface resistance value of 10 ⁴ to 10 ¹¹ Ω / □. By providing the first oxide layer 21, antistatic properties and electromagnetic wave shielding properties due to high conductivity are exhibited. In addition, since the first oxide layer 21 has a refractive index of 1.7 or more, it also serves as a high refractive index layer. Further, since the refractive index is 2.2 or less, it has appropriate characteristics as a low reflection film. The “refractive index” in the present invention is a refractive index in light having a wavelength of 550 nm.

The first oxide layer 21 is made of, for example, a mixture of In ₂ O ₃ (indium oxide) and SnO ₂ (tin oxide) (hereinafter referred to as ITO), and Sn is composed of Sn and In. A layer containing 5 to 20 atom% in the total (100 atom%), a layer made of SnO ₂ , a mixture of ZnO (zinc oxide) and Al ₂ O ₃ (aluminum oxide) (hereinafter referred to as AZO), And the layer etc. which contain Al 2-10 atomic% in the sum (100 atomic%) of Al and Zn, etc. are mentioned.

In the ITO layer, other metals other than Sn and In may be included as appropriate as an oxide as long as the physical properties are not impaired. For example, Ga, Si, Al, Mg, etc. may be included.
In the SnO ₂ layer, other metals other than Sn may be appropriately contained as necessary as long as the physical properties are not impaired. For example, In, Ga, Si, Al, Mg, etc. may be included.
In the AZO layer, other metals other than Al and Zn may be appropriately contained as necessary as long as the physical properties are not impaired. For example, In, Ga, Si, Mg, etc. may be included.

  The physical film thickness (hereinafter simply referred to as “film thickness”) of the first oxide layer 21 is preferably 30 nm or less, and particularly preferably 10 to 20 nm. The “film thickness” in the present invention is a film thickness measured by a stylus type surface roughness measuring machine.

The second oxide layer 22 and the fourth oxide layer 24 are low refractive index layers having a refractive index of 1.6 or less.
Examples of the second oxide layer 22 and the fourth oxide layer 24 include layers made of SiO ₂ (silicon dioxide).
In the 2nd oxide layer 22 and the 4th oxide layer 24, other metals other than Si may be suitably contained as needed as long as the physical properties are not impaired. For example, In, Sn, Ga, Al, Mg, etc. may be included.

The thickness of the second oxide layer 22 is preferably 20 to 40 nm, and more preferably 25 to 35 nm.
The thickness of the fourth oxide layer 24 is preferably 80 to 100 nm, and more preferably 85 to 95 nm.

The third oxide layer 23 is a mixture of In ₂ O ₃ and CeO ₂ (cerium oxide) (hereinafter referred to as ICO) in an amount of 90% by mass in the third oxide layer 23 (100% by mass). It is a layer containing the above. The third oxide layer 23 preferably contains 95% by mass or more of ICO, and is most preferably a layer made of only ICO. Moreover, it is preferable that the 3rd oxide layer 23 contains 10-30 atomic% in the sum (100 atomic%) of Ce and Ce.
In the third oxide layer 23, other metals other than Ce and In may be appropriately included as an oxide as required, as long as the physical properties are not impaired. For example, Sn, Ga, Al, Mg, etc. may be contained, and it is preferable that Sn is contained.

  The refractive index of the third oxide layer 23 is preferably 1.7 to 2.5, and more preferably 2 to 2.3. The third oxide layer 23 serves as a high refractive index layer. When the third oxide layer 23 contains 90% by mass or more of ICO, high transmittance can be obtained in the wavelength region of 420 to 450 nm, and high water resistance can be obtained.

The film thickness of the third oxide layer 23 is preferably 110 to 150 nm, and more preferably 120 to 140 nm.
As a method for forming each oxide layer, a physical vapor deposition method such as a vacuum vapor deposition method, a reactive vapor deposition method, an ion beam assisted vapor deposition method, a sputtering method or an ion plate method; a chemical vapor deposition method such as a plasma CVD method, etc. Is mentioned. The sputtering method is particularly preferable because it is easy to obtain a uniform film thickness in a large area.

The surface resistance value of the antireflection layer 20 of the antireflection film 1 for FED is preferably 10 ⁴ to 10 ¹¹ Ω / □. 10 ⁴ Ω / □ or more is preferable from the viewpoint of suppressing the occurrence of discharge, and 10 ¹¹ Ω / □ or less is preferable from the viewpoint of antistatic properties.

(Conductive layer)
The conductive layer 30 has a surface resistance value of 10 ⁴ to 10 ¹¹ Ω / □. Thereby, migration of alkali metal ions such as Na ⁺ in the face plate can be suppressed.

The conductive layer 30 is composed of SnO ₂ and In ₂ O ₃ and contains Sn in a total amount (100 atomic%) of Sn and In (30 to 50 atomic%, preferably 30 to 45 atomic%) ( Hereinafter, this is referred to as the present ITO layer.) Or Ga ₂ O ₃ , In ₂ O ₃ and SnO _2, and Ga is contained in 2 to 15 atomic% in the total (100 atomic%) of Ga, In and Sn. And a layer containing 2 to 15 atomic% of In (total of 100 atomic%) of Ga, In and Sn (hereinafter referred to as a GIT layer). When the conductive layer 30 is the present ITO layer or GIT layer, the function as a potential regulating layer can be sufficiently exerted, and migration in the FED faceplate can be suppressed.

By setting the Sn ratio in the ITO layer or the Ga and In ratio in the GIT layer within this range, the ITO layer or the GIT layer has sufficient chemical resistance while maintaining the visible light transmittance. As a result, the function as the potential regulating layer is not deteriorated for a long period of time, and the migration of the FED face plate can be suppressed for a long period of time. Moreover, since it has chemical resistance, it becomes difficult to be attacked by the pressure-sensitive adhesive, and as a result, a decrease in transmittance is suppressed. Also, by setting the Sn ratio in the present ITO layer or the Ga and In ratio in the GIT layer within this range, the gas barrier property is enhanced and the moisture permeation is suppressed. As a result, the Na ⁺ in the FED faceplate is increased. Migration of alkali metal ions such as is further suppressed.

  In the present ITO layer, other metals other than Sn and In may be appropriately included as an oxide as required, as long as the physical properties are not impaired. For example, Ga, Si, Al, Mg, etc. may be included.

  In the GIT layer, other metals other than Ga, In, and Sn may be appropriately included as necessary as long as the physical properties are not impaired. For example, Al, Mg, Si, etc. may be included.

5-20 nm is preferable and, as for the film thickness of the conductive layer 30, 5-10 nm is especially preferable.
As a method for forming the conductive layer 30, physical vapor deposition such as vacuum vapor deposition, reactive vapor deposition, ion beam assisted vapor deposition, sputtering, ion plate, etc .; chemical vapor deposition such as plasma CVD, etc. Can be mentioned. The sputtering method is particularly preferable because it is easy to obtain a uniform film thickness in a large area.

(Adhesive layer)
The adhesive layer 40 is a layer for attaching the FED antireflection film 1 to the outer surface of the FED face plate.
What is necessary is just to use a well-known adhesive as an adhesive. Repairability (easiness of reattaching work, such as removing the FED antireflection film 1 after attaching the FED antireflection film 1 to the face plate and then attaching the FED antireflection film 1 to the face plate again) For this purpose, an adhesive that has a low adhesive strength within 7 days after the antireflection film 1 for FED is attached to the face plate and has a high adhesive strength after 14 days is preferable.

In the antireflection film 1 for FED described above, since the conductive layer 30 is a specific ITO layer or GIT layer, the conductive layer 30 has sufficient chemical resistance while maintaining visible light transmittance. It becomes difficult to be attacked by the adhesive. As a result, since the function as the potential regulating layer does not deteriorate for a long time, the migration of the FED face plate can be suppressed. Moreover, the fall of the transmittance | permeability is suppressed.
In addition, since the conductive layer 30 is a layer made of a metal oxide, it is easier to form than the conventional layer made of carbon paste, and the productivity is good. Moreover, the visible light transmittance is also high.

(Other forms)
The antireflection layer in the antireflection film for FED of the present invention is not limited to the four-layer structure in the illustrated example, and may be any layer having both antireflection and antistatic functions.

The antireflection film for FED of the present invention may be provided with an antifouling layer on the antireflection layer 20 in order to protect the antireflection layer 20 and enhance the antifouling performance. By providing the antifouling layer, the function of the antireflection layer 20 is not hindered and can be easily wiped off when the outermost surface is soiled with fingerprints.
As the antifouling layer, an oil-repellent film containing perfluorosilane, fluorocarbon or the like is preferable.

Examples of the method for forming the antifouling layer include a vapor deposition method, a sputtering method, a coating drying method and the like as appropriate.
The film thickness of the antifouling layer is preferably 20 nm or less, and more preferably 10 nm or less.

The antireflection film for FED of the present invention may have a hard coat layer between the substrate 10 and the antireflection layer 20 in order to impart a desired hardness to the antireflection film 1 for FED.
The hard coat layer is preferably a material that is transparent and has a refractive index equal to the refractive index of the substrate 10 or a refractive index within ± 0.1 with respect to the refractive index of the substrate 10. Examples of the material of the hard coat layer include an ultraviolet curable acrylic resin, a silicone resin, or a material in which an additive is added thereto.

Examples of the method for forming the hard coat layer include known coating methods such as a bar coating method, a doctor blade method, a reverse roll coating method, and a gravure roll coating method.
The film thickness of the hard coat layer is preferably 10 μm or less.

Furthermore, an oxidation barrier layer may be provided between the base material 10 and the first oxide layer 21 in order to prevent oxidation during film formation and improve adhesion in all or part of each oxide layer. Good.
The oxidation barrier layer is a thin film formed to prevent oxidation of another layer formed thereunder, and has no optical meaning. Examples of the oxidation barrier layer include various metals or metal nitrides such as silicon nitride.

Examples of the method for forming the oxidation barrier layer include vapor deposition, sputtering, and CVD.
The film thickness of the oxidation barrier layer is preferably 5 nm or less.

<FED device>
The FED device of the present invention has an FED main body and the antireflection film for FED of the present invention directly attached to the viewing side of the FED main body. As a result, migration of alkali metal ions such as Na ⁺ in the face plate can be suppressed, and an FED device with good visibility can be obtained without causing clouding.

  The FED main body is formed on the inner surface of the face plate, for example, a glass element substrate, a glass face plate disposed away from the element substrate, a plurality of electron guns disposed on the inner surface of the element substrate, and the like. A phosphor layer and a metal back. The antireflection film for FED is attached to the outer surface of the face plate via an adhesive layer.

[Example 1]
(Conductive layer)
First, the surface of a polyethylene terephthalate (PET) film having a length and width of 50 cm and a thickness of 100 μm as the substrate 10 was cleaned by dry cleaning using an ion beam. In dry cleaning by an ion beam, argon ions ionized by an ion beam source into which a mixed gas of about 70% by volume of argon gas and about 30% by volume of oxygen gas is introduced into a sputtering apparatus and power of 100 W is applied. And irradiating the surface of the substrate 10 with oxygen ions.

While introducing a mixed gas of 7.5 volume% oxygen gas and 92.5 volume% argon gas into the magnetron sputtering apparatus, a mixed target of In ₂ O ₃ and SnO ₂ [In ₂ O ₃ : SnO ₂ = 60 : 40 (mass ratio)], pressure sputtering is performed under the conditions of pressure 0.15 Pa, frequency 100 kHz, power density 1.0 W / cm ² , inversion pulse width 1 μsec, and the surface of the substrate 10 has a thickness of 10 nm. Layer 30 was formed. When measured with an electron probe microanalyzer (EPMA), Sn is 37.4 atomic% and In is 62.6 atomic% in the total of Sn and In (100 atomic%) in the conductive layer 30. Met.

The surface resistance value of the conductive layer 40 was measured according to JIS K6911 using a digital ultrahigh resistance meter R8340 manufactured by Advantest Corporation. As a result, it was 5.0 × 10 ⁵ Ω / □. Further, the luminous transmittance (stimulus value Y defined in JIS Z 8701) measured from the conductive layer 30 side by a color analyzer TC1800 manufactured by Tokyo Denshoku Co., Ltd. was 89.54%. A transmission spectrum of a film having a conductive layer is shown in FIG.

(Antireflection layer)
Subsequently, the antireflection layer 20 was formed on the surface of the substrate 10 opposite to the surface on which the conductive layer 30 was provided.
First, the surface of the substrate 10 was cleaned by dry cleaning using an ion beam. In dry cleaning using an ion beam, a mixture gas of 67 volume% argon gas and 33 volume% oxygen gas is introduced into a sputtering apparatus, and argon ions and oxygen ionized by an ion beam source to which power of 100 W is applied. This was performed by irradiating the surface of the substrate 10 with ions.

While introducing a mixed gas of 2% by volume oxygen gas and 98% by volume argon gas into the magnetron sputtering apparatus, an ITO target [In ₂ O ₃ : SnO ₂ = 90: 10 (mass ratio)] was used and the pressure was 0. Pulse sputtering was performed under the conditions of .35 Pa, frequency 100 kHz, power density 1.5 W / cm ² , inversion pulse width 1.0 μsec, and the first oxide layer 21 (refractive index = 2.0) was formed.

While introducing a mixed gas of 40 volume% oxygen gas and 60 volume% argon gas into the magnetron sputtering apparatus, using a SiC (silicon carbide) target (trade name: SC, manufactured by Asahi Glass Ceramics Co., Ltd.), a pressure of 0.35 Pa The second oxide having a thickness of 30 nm made of SiO _{2 is} formed on the surface of the first oxide layer 21 by performing pulse sputtering under the conditions of a frequency of 100 kHz, a power density of 3.5 W / cm ² , and an inversion pulse width of 4.5 μs. Layer 22 (refractive index = 1.47) was formed.

While introducing a mixed gas of 1% by volume of oxygen gas and 99% by volume of argon gas into a magnetron sputtering apparatus, using an ICO target [In ₂ O ₃ : CeO ₂ = 70: 30 (mass ratio)], a pressure of 0 The third oxide layer 23 having a thickness of 125 nm is formed on the surface of the second oxide layer 22 by performing pulse sputtering under the conditions of .35 Pa, frequency 100 kHz, power density 3.6 W / cm ² , and inversion pulse width 1.0 μsec. (Refractive index = 2.2) was formed.

While introducing a mixed gas of 40 volume% oxygen gas and 60 volume% argon gas into the magnetron sputtering apparatus, using a polycrystalline silicon target, pressure 0.25 Pa, frequency 100 kHz, power density 5.0 W / cm ² , Pulse sputtering was performed under the condition of an inversion pulse width of 4.5 μs to form a 90 nm thick fourth oxide layer 24 (refractive index = 1.47) made of SiO _{2 on the} surface of the third oxide layer 23. .

  The luminous transmittance (stimulus value Y defined in JIS Z 8701) measured from the side of the antireflection layer 20 with a color analyzer TC1800 manufactured by Tokyo Denshoku was 94.85%. The luminous reflectance (stimulus value Y defined in JIS Z 8701) measured from the antireflection layer 20 side with a spectrophotometer (manufactured by Shimadzu Corporation, UV-3150) was 0.63%. The transmission spectrum of a film having a conductive layer and an antireflection layer is shown in FIG. 2, and the reflection spectrum is shown in FIG.

The chemical resistance of the conductive layer 30 of the film was evaluated as follows. The results are shown in Table 1.
Citric acid aqueous solution, phosphoric acid aqueous solution, magic phosphorus (trade name, manufactured by Kao Co., Ltd.), acetone, Mypet (trade name, manufactured by Kao Co., Ltd.) 2.5 μL each was dropped onto the conductive layer 30 and left for 24 hours, then wiped off, appearance Was observed. A case where no change was observed in the dropped portion was evaluated as ◯, and a case where a change was observed in the dropped portion was evaluated as ×.

(Adhesive layer)
An adhesive layer 40 (acrylic adhesive) having a length of 50 cm, a width of 50 cm, and a thickness of 20 μm is formed on the conductive layer 30, and exposed portions of the conductive layer 30 for measuring the surface resistance value are formed on both sides of the adhesive layer 40. Thus, an antireflection film 1 for FED was obtained. The pressure-sensitive adhesive of the pressure-sensitive adhesive layer 40 has a repairing property so that the adhesive strength becomes 2 to 10 N / 25 mm until 7 days after the formation of the pressure-sensitive adhesive layer 40, and the pressure-sensitive adhesive strength becomes 20 N / 25 mm after 14 days. Using.

The surface resistance value of the conductive layer 30 after the pressure-sensitive adhesive layer 40 was formed was measured according to JIS K6911 using a digital ultrahigh resistance meter R8340 manufactured by Advantest Corporation. Further, luminous transmittance (stimulus value Y defined in JIS Z 8701) was measured from the antireflection layer 20 side by a color analyzer TC1800 manufactured by Tokyo Denshoku Co., Ltd.
Next, the FED antireflection film 1 was left in an environment of a temperature of 60 ° C. and a humidity of 90% for 500 hours to perform a durability test of the FED antireflection film 1. The surface resistance value and luminous transmittance after the durability test were measured in the same manner.
As for the surface resistance value, a value in the range of 10 ⁴ to 10 ¹¹ Ω / □ was indicated as ◯, and a value outside the range was indicated as ×. With respect to the luminous transmittance, those that were 90% or more before the endurance test were marked with ◯, and those that were less than 90% were marked with ×. Further, after the endurance test, the case where the deterioration of the luminous transmittance was less than 5% was evaluated as “◯”, and the case where it was 5% or more was evaluated as “X”. The results are shown in Table 2.

[Comparative Example 1]
An antireflection film for FED was obtained and evaluated in the same manner as in Example 1 except that the conductive layer was formed as follows. The results are shown in Tables 1 and 2.
While introducing a mixed gas of 7.5 volume% oxygen gas and 92.5 volume% argon gas into the magnetron sputtering apparatus, a mixed target of In ₂ O ₃ and SnO ₂ [In ₂ O ₃ : SnO ₂ = 90 : 10 (mass ratio)], pulse sputtering is performed under the conditions of pressure 0.15 Pa, frequency 100 kHz, power density 1.0 W / cm ² , inversion pulse width 1 μsec, and the surface of the substrate 10 has a thickness of 10 nm. A layer was formed. When measured with an ESCA5500 manufactured by ULVAC-PHI, the conductive layer was measured with an electron probe microanalyzer (EPMA), and the total of Sn and In (100 atomic%) in the conductive layer 30 was Sn. Was 8.1 atomic%, and In was 91.9 atomic%.

[Comparative Example 2]
An antireflection film for FED was obtained and evaluated in the same manner as in Example 1 except that the conductive layer was formed as follows. The results are shown in Tables 1 and 2.
While introducing a mixed gas of 5 volume% oxygen gas and 95 volume% argon gas into the magnetron sputtering apparatus, an AZO target [ZnO: Al ₂ O ₃ = 95: 5 (mass ratio)] was used and a pressure of 0. Pulse sputtering was performed under the conditions of 21 Pa, a frequency of 100 kHz, a power density of 1.0 W / cm ² , and an inversion pulse width of 1 μsec, and a conductive layer having a thickness of 10 nm was formed on the surface of the substrate 10.

[Comparative Example 3]
An antireflection film for FED was obtained and evaluated in the same manner as in Example 1 except that the conductive layer was formed as follows. The results are shown in Tables 1 and 2.
While introducing a mixed gas of 38% by volume oxygen gas and 62% by volume argon gas into the magnetron sputtering apparatus, using a Sn target with a purity of 99.9%, pressure 0.32 Pa, frequency 50 kHz, power density 1.0 W. Pulsed sputtering was performed under the conditions of / cm ² and a reversal pulse width of 1 μs to form a conductive layer having a thickness of 10 nm on the surface of the substrate 10.

The antireflection film for FED of Example 1 had low luminous reflectance and high luminous transmittance. Moreover, it had an appropriate surface resistance value and was excellent in antistatic properties. Moreover, it was excellent in chemical resistance, and the change of the surface resistance value and luminous transmittance by an adhesive was suppressed.
Since the antireflection film for FED of Comparative Example 1 had a low Sn ratio in the conductive layer, it was inferior in chemical resistance (acid resistance), and the surface resistance value after the durability test was high.
In the antireflection film for FED of Comparative Example 2, since the conductive layer was AZO, the surface resistance value was high before the endurance test and the chemical resistance was inferior, so the transmittance after the endurance test was low.
The antireflection film for FED of Comparative Example 3 had a high surface resistance before the endurance test because the conductive layer was only SnO ₂ .

  The antireflection film for FED of the present invention has low reflectance and high transmittance over the entire visible light region, excellent antistatic properties, and can suppress migration of the FED faceplate. Useful.

It is a schematic sectional drawing which shows an example of the antireflection film for FED of this invention. It is a transmission spectrum of the film which has a conductive layer, and the film which has a conductive layer and an antireflection layer. It is a reflection spectrum of the film which has a conductive layer and an antireflection layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antireflection film for FED 10 Base material 20 Antireflection layer 30 Conductive layer

Claims (4)

An antireflection film for a field emission display in which an antireflection layer is provided on one surface of a substrate and a conductive layer is provided on the other surface,
An antireflection film for a field emission display, wherein the conductive layer has a surface resistance value of 10 ⁴ to 10 ¹¹ Ω / □ and a luminous transmittance of the antireflection film is 90% or more. The conductive layer is made of SnO ₂ and In ₂ O ₃ and contains 30 to 50 atomic% of Sn in total (100 atomic%) of Sn and In, or Ga ₂ O ₃ , In ₂ O ₃ and SnO ₂ , Ga is contained in 2 to 15 atomic% in the total of Ga, In and Sn (100 atomic%), and In is in the total (100 atomic%) of Ga, In and Sn. The antireflection film for a field emission display according to claim 1, which is a layer containing 2 to 15 atomic%. The antireflection layer has, in order from the substrate side, a first oxide layer having a refractive index of 1.7 to 2.2 and a surface resistance value of 10 ⁴ to 10 ¹¹ Ω / □, and a refractive index. A second oxide layer having a refractive index of 1.6 or less, a second oxide layer having a refractive index of 1.6 or less, a second oxide layer having a refractive index of 1.6 or less, a third oxide layer containing 90% by mass or more of a mixture of In ₂ O ₃ and CeO ₂ The antireflection film for field emission display according to claim 1 or 2, wherein the antireflection film is a layer composed of an oxide layer. The field emission display itself,
The field emission display apparatus which has the antireflection film for field emission displays as described in any one of Claims 1-3 directly affixed on the visual recognition side of this field emission display main body.

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