JP2005037806A - Manufacturing method of optical filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an optical filter which has high transparency, has a flat surface and does not necessitate degassing etc. when being stuck together with other member. <P>SOLUTION: The manufacturing method of optical filter comprises a flattened layer forming process that applies coating liquid for forming a flattened layer including at least transparent resin on a metal mesh in an electromagnetic wave shielding substrate consisting of an transparent substrate, an adhesive layer formed on the transparent substrate and the metal mesh formed on the adhesive layer, thereafter, hardening the coated liquid and forming a flattened layer and a flattening process that presses the flattened layer at a temperature of the glass transition temperature (Tg) of the transparent resin or more and, thereby, flattens the surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing an optical filter having electromagnetic wave shielding properties that can be used in a plasma display or the like.

  Conventionally, electronic devices that generate electromagnetic waves that are directly used by humans, such as display electron tubes for plasma displays, have been required to limit the intensity of electromagnetic wave emission to within the standard in consideration of the effects on the human body. Has been. In order to meet these demands, in general, an electromagnetic wave shield or the like is used to remove or attenuate an electromagnetic wave that flows out to the outside of an electronic device or the like that generates an electromagnetic wave, and a plasma display panel (hereinafter also referred to as PDP). In general, a display panel having a good transparency is provided on the front surface of the display panel.

As a method for shielding these electromagnetic waves, a method of laminating a metal such as silver by sputtering, a method of laminating a mesh made of a metal thin film on a transparent substrate (for example, Patent Document 1), etc. are known. .
When a mesh made of a metal thin film is used for such electromagnetic wave shielding, the cross-section is irregularly reflected when the metal mesh is viewed from an oblique direction, and the viewing angle is reduced. It was necessary to carry out the transparency treatment by laminating.
Furthermore, the optical filter is required to have a function of cutting or absorbing near infrared rays generated from the inside of the display in order to prevent malfunction of other devices and operability of remote control. Etc. are used.

  Therefore, a method has been proposed in which an adhesive layer for transparency is formed on the mesh made of the metal thin film, and an infrared absorbing film is laminated on the adhesive layer. However, in this method, when the pressure-sensitive adhesive layer is applied, bubbles at the bottom corners of the mesh void portion are difficult to escape, and when the pressure-sensitive adhesive layer and the metal mesh are bonded together, the bubbles are bitten by the optical layer. It causes the transparency of the filter to decrease. Therefore, after pasting the infrared absorbing film and the metal mesh, it is necessary to perform defoaming treatment such as leaving for a certain period of time in a reduced pressure environment in the autoclave, which causes problems in terms of manufacturing efficiency and cost. there were. Furthermore, even when the adhesive layer is formed, the unevenness of the surface of the metal mesh affects the flatness of the surface of the adhesive layer, and the unevenness of the surface of the adhesive layer results in poor transparency of the optical filter. there were.

JP 2002-311843 A

  Therefore, it is desired to provide a method for producing an optical filter that has high transparency, has a flat surface, and does not require defoaming treatment or the like when bonded to another member.

The present invention provides at least a transparent resin on the metal mesh of the electromagnetic wave shielding substrate having a transparent substrate, an adhesive layer formed on the transparent substrate, and a metal mesh formed on the adhesive layer. A planarization layer forming step of forming a planarization layer by curing after applying the coating liquid for forming a planarization layer containing,
A flattening step of flattening the surface by pressurizing the flattening layer at a temperature equal to or higher than the glass transition temperature (Tg) of the transparent resin is provided. .

  According to the present invention, since the flattening layer forming coating liquid is applied onto the metal mesh by the flattening layer forming step, the flattening layer is also formed in the void portion of the metal mesh, It is possible to prevent irregular reflection of the mesh cross section. Furthermore, since the flattened layer surface after the flattened layer forming step is flattened by the flattened step, the surface has no irregularities, and there is no irregular reflection of the metal mesh cross section. A filter can be manufactured.

  In addition, since the optical film manufactured according to the present invention has a flat surface, the optical filter manufactured according to the present invention and other members such as an infrared absorbing film and a plasma display panel are provided. At the time of pasting, air bubbles are not bitten and it is possible to eliminate the need for defoaming treatment or the like.

  In this invention, it is preferable that the glass transition point temperature (Tg) of the said transparent resin exists in the range of 30 to 150 degreeC. Thereby, in the planarization step, the planarization layer can be easily planarized at a temperature equal to or higher than the glass transition temperature of the resin.

  In the present invention, the pressurization is preferably performed by a mirror roll. This is because the surface of the planarization layer can be planarized efficiently.

  Furthermore, in this invention, the infrared absorber may contain in the said planarization layer. Thereby, it is not necessary to separately bond an infrared absorption film or the like to the optical filter manufactured according to the present invention, and an optical filter having an infrared absorption function and an electromagnetic wave shielding function can be manufactured.

  According to the present invention, since the flattening layer forming coating liquid is applied onto the metal mesh by the flattening layer forming step, the flattening layer is also formed in the void portion of the metal mesh, It is possible to prevent irregular reflection of the mesh cross section. Furthermore, since the flattened layer surface after the flattened layer forming step is flattened by the flattened step, the surface has no irregularities, and there is no irregular reflection of the metal mesh cross section. A filter can be manufactured.

  In addition, since the optical film manufactured according to the present invention has a flat surface, the optical filter manufactured according to the present invention and other members such as an infrared absorbing film and a plasma display panel are provided. At the time of pasting, air bubbles are not bitten and it is possible to eliminate the need for defoaming treatment or the like.

The present invention relates to a method for manufacturing an optical filter having high transparency and a flat surface.
The method for producing an optical filter of the present invention includes a transparent substrate, an adhesive layer formed on the transparent substrate, and a metal mesh formed on the adhesive layer. In addition, after applying a flattening layer forming coating solution containing at least a transparent resin, a flattening layer forming step of forming a flattening layer by curing,
A flattening step of flattening the surface by pressing the flattening layer at a temperature equal to or higher than the glass transition temperature (Tg) of the transparent resin.

  An example of the manufacturing method of the optical filter of this invention is demonstrated using FIG. The method for producing an optical filter of the present invention first includes an electromagnetic wave shielding comprising a transparent substrate 1, an adhesive layer 2 formed on the transparent substrate 1, and a metal mesh 3 formed on the adhesive layer 2. A planarization layer forming step for forming the planarization layer 5 on the metal mesh 3 in the substrate 4 is performed (FIG. 1A). Next, for example, using a mirror roll 6, a planarization step is performed in which the surface of the planarization layer 5 is pressurized at a temperature higher than the glass transition temperature (Tg) of the transparent resin contained in the planarization layer 5 (FIG. 1). (B)). Thereby, it can be set as the highly transparent optical filter which does not have an unevenness | corrugation etc. on the surface of the planarization layer 5 (FIG.1 (c)).

According to the present invention, since the planarizing layer forming coating liquid is applied onto the metal mesh in the planarizing layer forming step, the planarizing layer is filled in the voids of the metal mesh. Thereby, when the said metal mesh is seen from diagonally, it can prevent that light irregularly reflects in a mesh cross section. Further, since the surface of the flattening layer is flattened by the flattening step, an optical filter having no irregularities on the surface and having high transparency can be obtained. In addition, since the surface of the flattening layer is flat, bubbles may be caught when the optical filter manufactured according to the present invention is bonded to another member such as an infrared absorption film or a plasma display panel. Therefore, an optical filter that does not require a defoaming process or the like can be obtained.
Hereafter, each process in the manufacturing method of the above optical filters of this invention is demonstrated.

1. Flattening Layer Forming Step First, the flattening layer forming step in the optical filter manufacturing method of the present invention will be described. The planarization layer forming step in the method for producing an optical filter of the present invention is for electromagnetic wave shielding having a transparent base material, an adhesive layer formed on the transparent base material, and a metal mesh formed on the adhesive layer. In this step, a flattening layer is formed by applying a flattening layer-forming coating solution containing at least a transparent resin onto the metal mesh of the substrate, followed by curing.
In this step, first, the electromagnetic wave shielding substrate and the flattening layer forming coating solution are prepared, and then the flattening layer forming coating solution is applied onto the metal mesh in the electromagnetic wave shielding substrate. It can be carried out. Hereinafter, each structure used for this process is demonstrated.

(Coating liquid for flattening layer formation)
First, the flattening layer forming coating solution used in the flattening layer forming step of the present invention will be described. The planarization layer forming coating solution used in this step contains at least a transparent resin, and is applied onto a metal mesh in an electromagnetic wave shielding substrate described later.

  In the present invention, the transparent resin used in the flattening layer-forming coating solution is not particularly limited as long as it is transparent to visible light. Resin, ester resin, polycarbonate resin, urethane resin, cyclic polyolefin resin, polystyrene resin, or polytetrafluoroethylene (PTFE), a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether Perfluoroalkoxy resin (PFA), tetrafluoroethylene and hexafluoropropylene copolymer (FEP), tetrafluoroethylene and perfluoroalkyl vinyl ether and hexafluoropropylene copolymer (EPE), copolymer of tetrafluoroethylene and ethylene or propylene (ETFE), polychlorotrifluoroethylene resin (PCTFE), copolymer of ethylene and chlorotrifluoroethylene (ECTFE), vinylidene fluoride resin (PVDF), fluororesin such as vinyl fluoride resin (PVF) , Polyimide resins such as polyimide, polyamideimide, polyetherimide, and the like. Among them, acrylic resins, ester resins, and polycarbonate resins are preferable.

In the present invention, planarization is performed at a temperature equal to or higher than the glass transition temperature of the transparent resin in the planarization step described later, and therefore the glass transition temperature (Tg) of the transparent resin is 30 ° C. to 150 ° C. It is preferable to be within the range, particularly 40 ° C to 120 ° C.
The average molecular weight of the transparent resin is preferably in the range of 500 to 600,000, particularly 10,000 to 400,000. This is because a transparent resin having the above properties can be obtained.

  Here, the flattening layer forming coating solution used in this step is usually prepared by dissolving the transparent resin in a solvent or the like to obtain a target viscosity. Examples of the solvent used in the flattening layer forming coating solution in this step include ethyl acetate, toluene, methyl ethyl ketone (MEK), xylene, isopropyl alcohol (IPA), chloroform, tetrahydrofuran (THF), dimethylformamide ( DMF), acetonitrile, trifluoropropanol and the like.

  Further, at this time, the viscosity of the coating liquid for forming the flattening layer is appropriately selected depending on the application method, the type of resin, and the like, but is usually within a range of 0.01 Pa · s to 100 Pa · s. Especially, it is preferable to be in the range of 0.1 Pa · s to 10 Pa · s. Thereby, in this step, when applied onto a metal mesh, which will be described later, the flattening layer can be filled with a coating solution for forming a flattening layer and prevent irregular reflection of the cross section of the metal mesh. Because it can be.

  Here, in the present invention, the flattening layer forming coating solution may contain an infrared absorber. This is because the planarization layer can also perform the function of absorbing infrared rays, and a process of separately bonding an infrared absorbing film or the like is not necessary.

  Thus, when the infrared absorbing agent is contained in the planarization layer forming coating solution, among the above-described transparent resins, the hydroxyl value of the transparent resin is 10 or less, particularly 5 or less, particularly 0. Preferably there is. This is because when a hydroxyl group is present in the transparent resin, it may react with the hydroxyl group depending on the type of infrared absorber, and the hydroxyl value in the transparent resin is within the above range. This is because, for example, an infrared absorber having a counter ion can be prevented from reacting with a hydroxyl group contained in the transparent resin. Further, by using such a transparent resin, it is possible to obtain an optical filter having a function of absorbing infrared rays stably, and further, it is possible to expand the range of selection of infrared absorbers. Here, the hydroxyl value means the amount of potassium hydroxide required to neutralize acetic acid bonded to a hydroxyl group when 1 g of a sample is acetylated.

  Furthermore, it is preferable that the acid value of the transparent resin is 10 or less, particularly 5 or less, particularly 0. This is because the acid contained in the transparent resin can prevent the infrared absorber from reacting and the like, and can provide a more stable optical filter having an infrared absorption function. Here, the acid value means the amount of potassium hydroxide required to neutralize 1 g of the sample.

  Here, the infrared absorber used in the present invention is not particularly limited as long as it is a material that absorbs light in the infrared region. In general, the infrared region refers to a region of 800 to 1200 nm. In the infrared absorbent used in the present invention, the light transmittance in the region is preferably 20% or less, more preferably 10% or less. The above-mentioned transmittance is a value measured by a spectrophotometer UV-3100PC manufactured by Shimadzu Corporation according to the method described in JIS Z 8722 “Color Measurement Method—Reflection and Transmission Object Color”.

  Specific examples of infrared absorbers that can be used in the present invention include tin oxide, indium oxide, magnesium oxide, titanium oxide, chromium oxide, zirconium oxide, nickel oxide, aluminum oxide, zinc oxide, iron oxide, and antimony oxide. Inorganic infrared absorbers such as lead oxide and bismuth oxide, cyanine compounds, phthalocyanine compounds, naphthalocyanine compounds, naphthoquinone compounds, anthraquinone compounds, aluminum compounds, pyrylium compounds, cerium compounds, squarylium compounds, One or more organic infrared absorbers such as diimoniums, copper complexes, nickel complexes, and dithiol complexes can be used.

  Moreover, as said organic infrared absorber, specifically, (it is made from Nippon Kayaku Co., Ltd .: brand name) IRG-002, IRG-003, IRG-022, IRG-023, IRG-040, (hereinafter, Japan) Product name: IR-1, IR-10, IR-12, IR-14, TX-EX-906B, TX-EX-910B (hereinafter, Mitsui Chemicals Fine: product name) SIR-128 , SIR-130, SIR-132, SIR-159 (hereinafter referred to as Midori Chemical Co., Ltd .: trade name) MIR-101, MIR-111, MIR-121, MIR-102, MIR-1011, MIR-1021, etc. It is done.

  In addition to the above-described materials, the coating liquid for forming a flattening layer used in the present invention contains a filler, a softening material, an antioxidant, an ultraviolet absorber, a crosslinking agent, and the like as necessary. You may do.

(Electromagnetic wave shielding substrate)
Next, the electromagnetic wave shielding substrate used in this step will be described.
The electromagnetic wave shielding substrate used in this step has a transparent base material, an adhesive layer formed on the transparent base material, and a metal mesh formed on the adhesive layer. Hereinafter, each structure of the electromagnetic wave shielding substrate used in this step will be described.

a. Metal Mesh First, the metal mesh of the electromagnetic wave shielding substrate used in this step will be described. The metal mesh used in this step has a function of shielding electromagnetic waves generated from a plasma display or the like. Such a metal mesh is formed by laminating a metal foil on a transparent base material described later by an adhesive layer described later and etching the metal foil into a mesh shape.

In this step, the metal mesh is not particularly limited as long as it has electromagnetic wave shielding properties. For example, copper, iron, nickel, chromium, aluminum, gold, silver, stainless steel, Tungsten, chromium, titanium, or the like can be used.
In the present invention, among the above, copper is preferable from the viewpoints of electromagnetic shielding properties, etching processing suitability, and handling properties. Moreover, as a kind of copper foil used, although rolled copper foil, electrolytic copper foil, etc. are mentioned, it is especially preferable that it is electrolytic copper foil. This is because the thickness can be made uniform with a thickness of 10 μm or less, and the adhesion with chromium oxide or the like can be made good when blackened.

Here, in the present invention, it is preferable that one side or both sides of the metal foil is blackened. The blackening process is a process of blackening the surface of the metal mesh with chromium oxide or the like. In the optical filter, the blackened surface is arranged to be a surface on the viewer side. The external light on the surface of the optical filter is absorbed by chromium oxide or the like formed on the surface of the metal mesh by this blackening treatment, so that it is possible to prevent light from being scattered on the surface of the optical filter, and good visibility Therefore, the optical filter can be obtained. Such a blackening treatment can be performed by applying a blackening treatment liquid to the metal foil. As a blackening treatment method, different oxycarboxylic acid compounds such as tartaric acid, malonic acid, citric acid, and lactic acid are added to a CrO ₂ aqueous solution or a chromic anhydride aqueous solution to convert a part of hexavalent chromium into trivalent chromium. The reduced solution or the like can be applied by a roll coating method, an air curtain method, an electrostatic atomization method, a squeeze roll coating method, a dipping method or the like and dried. In addition, this blackening process may be performed after a metal foil is bonded to a transparent base material described later by an adhesive layer described later and etched into a mesh shape.

  In the present invention, it is preferable that the black density of the surface of the blackened metal foil is 0.6 or more. This is because the visibility can be further improved. Here, the black density is set to the density standard ANSI T as the observation viewing angle 10 °, the observation light source D50, and the illumination type using GRETAG SPM100-11 (manufactured by KIMOTO) of COLOR CONTROL SYSTEM. It is a value measured later.

Moreover, in this invention, it is preferable that the film thickness of the said metal foil exists in the range of 1 micrometer-100 micrometers, especially in the range of 5 micrometers-20 micrometers. If the film thickness is larger than the above range, it becomes difficult to make the pattern line width fine and fine by etching, and if it is thinner than the above range, sufficient electromagnetic wave shielding properties cannot be obtained.
Furthermore, in this invention, it is preferable that the said metal foil has the 10-point average roughness based on JISB0601 in the range of 0.5 micrometer-10 micrometers. If it is smaller than the above range, even if the blackening treatment is performed, the external light on the surface of the optical filter is specularly reflected, so that the visibility is deteriorated. This is because it becomes difficult to apply the resist or the resist.

  Here, the etching of the metal foil is performed after being bonded onto a transparent substrate described later using an adhesive layer described later. In the present invention, this etching can be performed by an ordinary photolithography method, for example, by applying a resist on the surface of a metal foil, drying, and then exposing the resist with a pattern plate and developing the resist. Can do.

The metal mesh as described above used in the present invention preferably has a surface resistance in the range of 10 ⁻⁸ Ω / □ to 5 Ω / □, and more preferably in the range of 10 ⁻⁴ Ω / □ to 3Ω / □. In general, the electromagnetic wave shielding property can be measured by surface resistance. It can be said that the lower the surface resistance, the better the electromagnetic wave shielding property. Here, the value of the surface resistance is determined by a method described in JIS K 7194 “Resistivity test method by conductive probe four-probe method” by a surface resistance measuring device, Loresta-GP Co., Ltd., Dia Instruments. It is a measured value.

  In the present invention, the metal mesh after the etching treatment is preferably in the range of 50 μm □ to 500 μm □, more preferably in the range of 100 μm □ to 400 μm □, particularly in the range of 200 μm □ to 300 μm □, Further, the mesh line width is preferably in the range of 5 μm to 20 μm. If the mesh line width is thinner than the above range, disconnection may occur, which is not preferable from the electromagnetic shielding surface, and if the mesh line width is thicker than the above range, the visible light transmittance is low, This is because, for example, the brightness of the plasma display is lowered, which is not preferable.

b. Next, the transparent substrate in the electromagnetic wave shielding substrate used in the present invention will be described. The transparent substrate used in the present invention is transparent to visible light, and is an adhesive layer described later and the metal mesh laminated on the adhesive layer.

In the present invention, the type of the transparent substrate is not particularly limited as long as the transparent substrate has transparency and an adhesive layer can be formed. For example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN) ), Polycarbonate, acrylic (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, etc., and in particular, from the viewpoint of cost and handleability, it should be PET Is preferred.
Moreover, in this invention, it is preferable that the film thickness of this transparent base material exists in the range of 12 micrometers-300 micrometers.

c. Next, the adhesive layer in the electromagnetic wave shielding plate used in the present invention will be described. The type of the adhesive layer used in the present invention is not particularly limited as long as it is a layer capable of adhering the above-described metal mesh and transparent substrate. Since the metal foil and the transparent base material constituting the mesh are bonded to each other by the adhesive layer, and then the metal foil is meshed by etching, the adhesive layer preferably has etching resistance.

In the present invention, specific examples of the material for the adhesive layer include acrylic, ester, urethane, fluorine, polyimide, epoxy, polyurethane ester, and the like.
Further, the adhesive layer used in the present invention may be an ultraviolet curable type or a thermosetting type. In the present invention, the transparent substrate and the metal foil can be bonded by using a dry lamination method, a wet lamination method or the like using these adhesive layers.

In this invention, it is preferable that the film thickness of this contact bonding layer exists in the range of 0.5 micrometer-50 micrometers. As a result, the transparent base material and the metal mesh can be firmly bonded, and the transparent base material can be prevented from being affected by the etching solution during etching to form the metal mesh. It is.
In the present invention, the adhesive layer may contain an infrared absorbent as described in the above-mentioned section of the flattening layer forming coating solution. This is because an infrared absorption function can be imparted to the optical filter manufactured according to the present invention without bonding an infrared absorption film or the like.

d. Next, the electromagnetic wave shielding substrate used in the present invention will be described. The electromagnetic wave shielding substrate used in the present invention is not particularly limited as long as the adhesive layer is formed on the transparent base material and the metal mesh is formed on the adhesive layer. Depending on the above, in addition to the metal mesh, the transparent substrate, and the adhesive layer, a reinforcing material or the like may be included.

(Coating and curing of coating liquid for flattening layer formation)
Next, application | coating and hardening of the said coating liquid for planarization layer formation in this process are demonstrated. In this step, the flattening layer is formed by applying and curing the above-described flattening layer forming coating solution on the metal mesh in the electromagnetic wave shielding substrate described above.

  The application of the flattening layer-forming coating liquid in this step is not particularly limited as long as it can be applied onto the electromagnetic wave shielding substrate. For example, spin coating, Known coating methods such as a roll coating method, a spray coating method, a dip coating method, and a bead coating method can be used.

  As for the curing method, if it is possible to cure the flattening layer forming coating liquid applied by the above method, it is appropriately selected depending on the flattening layer forming coating liquid, A known curing method can be used.

  The flattening layer formed in this way is preferably formed so as to cover the surface of the metal mesh. That is, it is preferably thicker than the thickness of the metal mesh. Specifically, the average film thickness of a portion where the metal mesh is not formed, for example, a shown in FIG. 1A, is in the range of 10 μm to 50 μm. Preferably there is. This is because the surface can be flattened by the flattening step described later without being affected by the unevenness of the metal mesh.

2. Flattening Step Next, the flattening step in the optical filter manufacturing method of the present invention will be described. In the planarization step of the present invention, the planarization layer formed by the planarization layer formation step is planarized by pressing at a temperature equal to or higher than the glass transition temperature of the transparent resin contained in the planarization layer. This is a step of flattening the layer surface.

In this step, the method is not particularly limited as long as the surface of the flattening layer can be pressed and flattened. For example, a mirror roll, a hard metal steel plate, a hard metal sphere, etc. In the present invention, it is preferable to pressurize using a mirror roll to flatten the surface of the flattening layer. This is because the planarizing layer can be planarized efficiently.
Further, in this step, the pressure which is pressurized on the kind of the transparent resin or the like, but is appropriately selected usually in the range of linear pressure ^{0.1kg / cm 2 ~30kg / cm 2} , inter alia 1 kg / It is preferable to be within the range of cm ^{2 to} 10 kg / cm ² .
The planarization step is performed at the glass transition temperature (Tg) of the transparent resin, and the specific temperature is appropriately selected from the glass transition temperature (Tg) of the transparent resin. Usually, it is preferably in the range of 30 ° C to 170 ° C, and more preferably in the range of 50 ° C to 120 ° C.

Here, the surface of the optical filter after being flattened by this step can be quantified by the surface roughness. According to JIS B0601-1984, the surface roughness meter is SE-3AK manufactured by KASEKA Laboratory. It is preferable that the measured surface roughness Rz is in the range of 0.05 to 5, particularly 0.1 to 3.
Further, the surface roughness is reflected in haze (turbidity), and haze is measured by the method described in JIS K 7105 “Testing methods for optical properties of plastics” manufactured by Color Computer SM-C Suga Test Instruments. Can be measured. About this haze, it is preferable that it is 0.1-3 in the range of 0.05-5. This is because, for example, when other members are bonded onto the planarizing layer, an optical filter having high transparency and no defoaming treatment can be obtained without air bubbles being bitten. .

In addition, the transparency of the optical filter manufactured according to the present invention is preferably such that the luminous transmittance is 40% or more, and especially 50% or more. This is because when the optical filter is used in, for example, a plasma display, the visibility can be improved. Here, the visible light means light in a range of 380 nm to 780 nm, and the luminous transmittance is JIS Z8701 color expression method XYZ table using a spectrophotometer UV-3100 (Shimadzu Corporation). Measured according to the measurement method described in the color system and X ₁₀ Y ₁₀ Z ₁₀ display system, and measured the transmittance in the range of 380 nm to 780 nm calculated by JIS Z 8722 color measurement method-reflection and transmission object color It is the value.

3. Other In the present invention, in addition to the flattening layer forming step and the flattening step, a step of attaching an infrared absorbing film on the flattened layer after the flattening step as necessary, for example, neon light And a step of attaching a neon light absorbing layer that absorbs light.
The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described in more detail through examples and comparative examples.

(Example 1)
<Preparation of electromagnetic shielding substrate>
Copper foil (Furukawa Circuit Foil, EXP-WS, thickness 10 μm) and polyethylene terephthalate (Toyobo A4300 thickness 100 μm), one side of which is blackened by chromate treatment, are urethane adhesives ( After dry lamination with Tg of 20 ° C, average molecular weight of 30,000, acid value of 1, and hydroxyl value of 9), the resist is coated on the copper foil, and then exposed and developed to remove unnecessary copper foil portions. Was removed by etching to form a metal mesh of 300 μm □ and a line width of 10 μm. At this time, when the PDP panel is manufactured, the blackened surface is set to be the viewing side (human side), and thus is set to the non-bonding surface side.

<Fabrication of planarization layer>
Next, in a transparent resin acrylic binder (Tg 100 ° C., average molecular weight 250,000, acid value 0, hydroxyl value 0) diluted with a solvent to a solid content of 20 wt%, Nippon Kayaku IRG-022 (diimonium dye) A total of 0.5 g / m ² of infrared absorbing dyes of 0.3 g / m ² and IR-1 (phthalocyanine-based) 0.2 g / m ² manufactured by Nippon Shokubai was mixed. The resin binder mixed with the red ray absorbing dye was applied on the electromagnetic shielding mesh prepared above with an applicator so that the dry film thickness was 30 μm (non-mesh part film thickness), and the wind speed was 5 to 20 m / sec. The film was dried at 100 ° C. for 1 minute in an oven exposed to dry air. After coating and drying, the surface of the flattened layer is pressed against the surface of the flattened layer by applying a pressure of 120 ° C. and a line thickness of 1 kg / cm ^{2 with} a mirror roll having a surface unevenness higher than the Tg of the resin binder. A planarization layer was prepared by erasing.

<Preparation of adhesive layer>
On the release film surface, an acrylic adhesive (Tg-40 ° C., average molecular weight 650,000, acid value 7, hydroxyl value 0) diluted with a solvent to a solid content of 20% is applied to a dry film thickness of 10 μm. And it dried for 1 minute at 100 degreeC in the oven which the dry air with a wind speed of 5-20 m / sec hits, and produced the adhesion layer. The adhesive layer was adhered to the transparent substrate (PET) side of the electromagnetic wave shield with a laminate roll having a temperature of 23 ° C. and a linear pressure of 1 kg / cm ² . Thereafter, the release film was peeled off, and the pressure-sensitive adhesive surface side was laminated on the PDP front panel.

(Example 2)
The same procedure as in Example 1 was performed except that the adhesive layer was adhered to the flattening layer side of the electromagnetic wave shield and laminated on the PDP front panel.

(Example 3)
The same process as in Example 1 was performed except that the planarizing layer was formed to have a dry film thickness of 20 μm (non-mesh portion film thickness).

(Example 4)
The same process as in Example 1 was performed except that the planarizing layer was formed to have a dry film thickness of 15 μm (non-mesh film thickness).

(Example 5)
The same procedure as in Example 1 was conducted except that the electromagnetic wave shielding substrate was as follows and the planarizing layer did not contain an infrared absorber.

<Preparation of electromagnetic shielding substrate>
A transparent resin acrylic binder (Tg 60 ° C., average molecular weight 250,000, acid value 0, hydroxyl value) diluted with polyethylene terephthalate (Toyobo A4300 thickness 100 μm) as an infrared absorber-containing adhesive layer with a solid content of 20 wt%. 0), Nippon Kayaku IRG-022 (diimonium dye) 0.3 g / m ² and Nippon Shokubai IR-1 (phthalocyanine) 0.2 g / m ² are combined. 0.5 g / m ^{2 was} mixed. The resin binder mixed with the red ray absorbing dye is coated on the PET so as to have a dry film thickness of 20 μm with an applicator, and is dried at 100 ° C. for 1 minute in an oven that receives dry air with a wind speed of 5 to 20 m / sec. Dried to form an adhesive layer.
The adhesive layer and a copper foil (Furukawa Circuit Foil, EXP-WS, thickness 9 μm) whose one side was blackened by chromate treatment were bonded together by dry lamination. At this time, the lamellar temperature was set to 80 ° C. which is equal to or higher than Tg of the transparent adhesive layer, and the linear pressure was set to 1 kg / cm ² . Then, after apply | coating a resist on the said copper foil, by exposing and developing, the unnecessary copper foil part was etched away and the metal mesh of 300 micrometers square and line width 10 micrometers was formed. At this time, when the PDP panel is manufactured, the blackened surface is set to be the viewing side (human side), and thus is set to the non-bonding surface side.

(Example 6)
Example 1 except that the adhesive layer was as follows, the planarizing layer did not contain an infrared absorber, and the adhesive layer was adhered to the planarizing layer side of the electromagnetic wave shield and laminated on the PDP front panel. The same was done.

<Preparation of adhesive layer>
IRG-022 (diimonium dye) manufactured by Nippon Kayaku Co., Ltd. in an acrylic binder (Tg-40 ° C., average molecular weight 650,000, acid value 7, hydroxyl value 0) as an adhesive layer on the release film. 3g / ^{m 2} and Japan catalyst made of IR-1 (phthalocyanine) was performed using two types of infrared-absorbing dye of 0.2g / ^{m 2} narrowing mix a total of 0.5g / ^{m 2.} The resin binder mixed with the red ray absorbing dye is coated with an applicator so as to have a dry film thickness of 10 μm, and dried at 100 ° C. for 1 minute in an oven in which dry air with a wind speed of 5 to 20 m / sec is applied. A containing adhesive layer was formed.

(Example 7)
The flattening layer was formed in the same manner as in Example 1 except that a transparent resin urethane binder (Tg 30 ° C., average molecular weight 50,000, acid value 25, hydroxyl value 10) was used instead of the transparent resin acrylic binder. It was.

(Example 8)
The flattening layer was formed in the same manner as in Example 1 except that a transparent resin urethane binder (Tg 50 ° C., average molecular weight 50,000, acid value 25, hydroxyl value 10) was used instead of the transparent resin acrylic binder. It was.

(Comparative Example 1)
The same operation as in Example 1 was performed except that the flattening was not performed with a mirror roll.

(Comparative Example 2)
The same operation as in Example 2 was performed except that the flattening was not performed with a mirror roll.

(Comparative Example 3)
The same operation as in Example 3 was performed except that the flattening was not performed with a mirror roll.

(Comparative Example 4)
The same operation as in Example 4 was performed except that the flattening was not performed with a mirror roll.

(Comparative Example 5)
The same operation as in Example 5 was performed except that the flattening was not performed with a mirror roll.

(Comparative Example 6)
The same operation as in Example 6 was performed except that the flattening was not performed with a mirror roll.

(Comparative Example 7)
It carried out similarly to Example 7 except not having planarized with the mirror roll.

(Comparative Example 8)
The same operation as in Example 8 was performed except that the flattening was not performed with a mirror roll.

<Evaluation>
Surface roughness (Rz) and transparency (haze: turbidity) of the optical film obtained by laminating the electromagnetic wave shield and the flattening layer obtained in Examples 1 to 8 and Comparative Examples 1 to 8. Table 1 and Table 2 show the measurement results of the aperture ratio, the visibility, the transparency, the luminous transmittance and the infrared transmittance immediately after production, and the luminous transmittance and the infrared transmittance after 90 hours at 60 ° C. for 90%. .

The above measurement was performed under the following measurement conditions.
Surface roughness: According to JIS B0601-1984, surface roughness was measured with SE-3AK manufactured by KASEKA Laboratory.
Transparency: Haze was measured by the method described in JIS K 7105 “Testing method for optical properties of plastic” manufactured by Color Computer SM-C Suga Test Instruments.
Aperture ratio: A photograph of the surface of the electromagnetic shielding mesh was taken using an optical microscope, the areas of the copper mesh portion and the void portion of the photograph were measured, and the aperture ratio was calculated from the area ratio.
Visibility: Confirmation was made visually.
Transparency: Haze (turbidity) was measured by the method described in JIS K 7105 “Testing method for optical properties of plastic” manufactured by Color Computer SM-C Suga Test Instruments.
Luminous transmittance: measured using a spectrophotometer UV-3100 (Shimadzu Corporation) according to the measurement method described in JIS Z8701 color expression method XYZ color system and X ₁₀ Y ₁₀ Z ₁₀ display system, and JIS Z 8722 The transmittance in the range of 380 nm to 780 nm calculated by the color measurement method-reflected and transmitted object color was measured.
Infrared transmittance: Spectrophotometer UV-3100PC Measured by Shimadzu Corporation according to the method described in JIS Z 8722 “Measurement method of color—reflection and transmission object color”.

  The optical films in Examples 1 to 8 of the present invention obtained above were compared with Comparative Examples 1 to 8 in which both transparency (Rz) and haze were not flattened with a mirror roll. It was low and the flatness was good.

  For Example 1 to Example 8, when an optical film with a flattened electromagnetic wave shield is directly laminated on the surface of the plasma display, the etched cross section of the electromagnetic wave shield mesh is caused by the effect of flattening the metal mesh. It had transparency and good electromagnetic wave shielding ability to recognize an image without glare even when viewed from an oblique direction near the blind spot of the plasma display without irregular reflection.

  In addition, it has an infrared absorption filter having a transparent resin base material on which an infrared absorption layer, an adhesive layer and the like are usually laminated, but in the present invention, the near infrared ray generated from the inside of the display with the smallest possible layer structure coated on the display. (Light) was cut or absorbed, and the light emitted from the display panel and the incident external light, in particular, a specific wavelength of visible light could be absorbed. Thereby, there was no malfunction of other equipment, and good visibility was obtained by improving the contrast of the image on the display screen. In addition, with respect to electromagnetic wave shielding, by using a mesh made of a copper thin film, it was particularly suitable for etching processing, and the electromagnetic wave shielding effect could be enhanced. Furthermore, by blackening the mesh made of a metal thin film, the ability to absorb outside light is particularly enhanced, and the visibility can be further improved.

  Here, with respect to Example 1 to Example 6, even after the wet heat resistance test 60 ° C. and 90% for 1000 hours, the infrared absorption performance was maintained in the initial state and was in a good state. However, for Example 7 and Example 8, the surface flatness, which is the object of the present invention, is good, but the acid and hydroxyl groups of the resin used for the planarization layer containing the infrared absorber are included. Due to the influence, the infrared transmittance and the like were lowered.

It is process drawing which shows an example of the optical filter manufacturing method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transparent base material 2 ... Adhesion layer 3 ... Metal mesh 4 ... Substrate for electromagnetic wave shielding 5 ... Flattening layer

Claims (4)

Planarization containing at least a transparent resin on the metal mesh of the electromagnetic shielding substrate having a transparent substrate, an adhesive layer formed on the transparent substrate, and a metal mesh formed on the adhesive layer A planarization layer forming step of forming a planarization layer by applying a coating liquid for layer formation and then curing,
A flattening step of flattening the surface by pressurizing the flattening layer at a temperature equal to or higher than the glass transition temperature (Tg) of the transparent resin.   2. The method for producing an optical filter according to claim 1, wherein a glass transition temperature (Tg) of the transparent resin is within a range of 30 ° C. to 150 ° C. 3.   The method of manufacturing an optical filter according to claim 1, wherein the pressurization is performed by a mirror roll.   The method for producing an optical filter according to any one of claims 1 to 3, wherein an infrared absorber is contained in the planarizing layer.

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