JP2007264579A - Optical filter for display and plasma display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical filter which makes display of an PDP visible with high contrast and can be supplied at a low cost with satisfactory mass productivity in an optical filter to be directly attached as a plate to the front of an image display glass plate of the PDP. <P>SOLUTION: The optical filter to be directly attached to the front of the image display glass plate G of the plasma display comprises a multilayered structure having a polyethylene terephthalate base material 11, a plurality of functional layers and adhesive layers. The optical filter 10 is characterized in that the refractive indices of the adhesive layers 12, 17 interposed between the polyethylene terephthalate base material 11 and the fuctional layer or between the functional layers are so adjusted as to exist in the middle of the refractive indices of the respective layers when the refractive index difference of the two layers verging on the adhesives is ≥0.10. The plasma display is constituted by pasting such optical filter to the front of the image display glass plate G via the adhesive layers 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical filter suitable for a display, particularly a plasma display, and a plasma display.

  Image display on a plasma display panel (hereinafter sometimes abbreviated as PDP) is caused by excitation of xenon and neon filled in the PDP by discharge, and a line spectrum from the ultraviolet region to the near infrared region is generated. When the ultraviolet rays in this light hit the phosphor, visible light for image display is generated from the phosphor.

As described above, near infrared light having a wavelength of 800 nm to 1000 nm is emitted from the PDP in addition to visible light, which may cause malfunction of an infrared remote controller such as a plasma display device or a video device. Moreover, since electromagnetic waves with a frequency of 30 MHz to 130 MHz are generated from the PDP, it may affect surrounding computers or computer-utilized devices, and may affect human bodies and animals. It is said that it is desired not to leak the generated electromagnetic wave to the outside as much as possible.
Furthermore, orange light emission may occur from neon filled in the PDP, and the color tone of the image may be out of order.
Further, when external light (fluorescent lamp) is inserted into the front surface of the PDP, the contrast of the image is lowered due to the reflected light, making it difficult to see the screen.

  For this reason, in a plasma display, an optical filter in which an electromagnetic wave shielding layer, a near infrared absorption layer, a color correction layer, and an antireflection layer are laminated on a substrate made of tempered glass or plastic is disposed on the front surface of the PDP. , Prevention of leakage of electromagnetic waves, leakage of near infrared rays, correction of color tone, and prevention of reflection of external light.

  Further, the surface temperature of the front surface of the PDP may reach about 90 ° C. However, the front surface of the PDP is cooled by arranging this optical filter with a gap for air cooling in front of the PDP. At the same time, by arranging an optical filter with a gap in front of the PDP, it protects the front of the PDP made of tempered glass from direct impact from the outside, and prevents damage to the front of the PDP.

  By the way, the PDP is required to be thin, but the above-described plasma display is not sufficient in terms of thinning because the air-cooling gap is provided. Moreover, the presence of the air-cooling gap causes a problem that the external light is reflected twice between the filter and the front surface of the PDP, and the contour of the image is blurred.

In order to prevent such double reflection, an optical filter has been developed for being attached directly to the front surface of the PDP. For example, on one surface of the light-transmitting film, a (meth) acrylic resin containing at least one selected from a neon cut dye, a xenon cut dye and a near infrared cut dye and carbon black and containing a crosslinking agent is used as an adhesive component. Disclosed is a coloring / adhesive film for electronic displays in which an adhesive layer is provided and at least one layer selected from a hard coat layer, a conductive layer, an antiglare layer and an antireflection layer is laminated on the other surface. (For example, refer to Patent Document 1).
However, this coloring and pressure-sensitive adhesive film for electronic displays has been tried to give various functions to the pressure-sensitive adhesive layer to be attached to the front surface of the PDP and to reduce the layer structure. No consideration is given to a decrease in contrast due to interface reflection caused by the difference between the refractive index of the glass plate on the front surface of the PDP, the pressure-sensitive adhesive layer, and the light-transmitting film.
That is, the contrast is
Contrast = (white display brightness + external light reflection) / (black display brightness + external light reflection)
Assuming that white luminance = 100, black luminance = 2, and external light reflection = 10, when there is no external light reflection, contrast = 100/2 = 50. = 110/12 = 9.2, and the contrast decreases.
In the conventional PDP direct attachment filter, assuming that the optical filter outer surface reflectance is 0.5%, the optical filter transmittance is 40%, and the PDP interface reflection is about 5%.
External light reflection = 0.5 + (40 × 0.05 × 0.4) = 1.3%
External light reflection is assumed, and the interface reflection between the directly attached optical filter and the PDP is assumed to be affected.

On the other hand, Patent Document 2 relates to a filter for a display device such as a cathode ray tube, a liquid crystal display device, and a plasma display device, and a method for manufacturing the same, and in particular, has high surface strength and excellent scratch resistance. A filter for a display device and a method for manufacturing the same are disclosed, in which reflection of external light between layers (interfaces) of the pressure-sensitive adhesive layer for application is suppressed, and the filter can be reused by peeling.
The display device filter disclosed in Patent Document 2 is used by forming at least one antireflection optical thin film on one surface of a glass substrate and sticking the other surface to the display surface of the display device. In the filter for a display device, the first pressure-sensitive adhesive layer formed on the surface of the glass substrate attached to the display device, and the first pressure-sensitive adhesive layer attached to the first pressure-sensitive adhesive layer A plastic film layer made of a material whose refractive index matches or substantially matches that of the agent layer, and the first pressure-sensitive adhesive layer and the plastic film layer that are attached to the display surface of the plastic film layer and the display device, And a second pressure-sensitive adhesive layer made of a material having the same or almost the same refractive index. In the filter for a display device of the present invention, it is preferable that the range in which the refractive indexes substantially coincide is a range in which the difference in refractive index is ± 0.02 in the visible light intermediate region (450 nm to 650 nm). It is said.

  That is, the refractive indexes of the three layers of the first pressure-sensitive adhesive layer, the plastic film layer, and the second pressure-sensitive adhesive layer that are interposed between the glass on the display surface of the display device and the glass substrate of the filter are made to match or substantially match. As a specific example, the refractive index of the display panel and the substrate (thickness: 200 μm) is 1.54, whereas the refractive index of the glass is 1.54 and the acrylic adhesive (refractive index is 1.48). ), Polymethyl methacrylate film (refractive index 1.48) as a resin film, Example 2: acrylic adhesive (refractive index 1.48), cellulose triacetate (TAC, refractive index 1.48) as a resin film, Example 3: A combination of a silicon-based adhesive (refractive index 1.43) and polychlorotrifluoroethylene (PCTFE, refractive index 1.43) as a resin film is disclosed.

However, in the configuration of the filter described in Patent Document 2, the resin film is interposed for reinforcement of thin flat glass (thickness 0.03 to 1 mm) as a glass substrate, removal of the filter, reworkability, etc. A functional layer is not formed on the resin film layer.
In addition, polyethylene terephthalate (hereinafter sometimes referred to as PET) is suitable as a substrate for optical filters because of its excellent transparency, mechanical properties, heat resistance, weather resistance, price, and continuous productivity of filters. It is also known to use PET as a substrate (base material) instead of the glass substrate, but in that case, no consideration is given to how the refractive index of the adhesive layer should be.
That is, conventionally, in an optical filter that is directly attached as a front plate to an image display glass plate of a plasma display, a polyethylene terephthalate substrate and a functional layer in a multilayer structure having a polyethylene terephthalate substrate, a functional layer, and an adhesive layer. The refractive index of the adhesive layer interposed between the layers and / or the adhesive layer interposed between the functional layers is not considered in terms of preventing reflection of external light and improving the contrast.

JP 2003-82302 A JP-A-11-305006

  The present invention has been made in view of the above problems. In an optical filter that is directly attached to the front surface of an image display glass plate of a PDP, the display of the PDP can be visually recognized with high contrast, and mass productivity is good. The main object is to provide an optical filter that can be supplied at low cost.

In order to solve the above-mentioned problems, the present inventors have proposed an adhesive layer interposed between the polyethylene terephthalate base material and the functional layer and an adhesive layer interposed between the functional layers in order to reduce external light reflection. Paying attention to the refractive index of the agent layer, the inventors have intensively studied the method of adjusting the refractive index, and have completed the present invention.
That is, the present invention
(1) A multilayer optical filter having a polyethylene terephthalate base, a plurality of functional layers and an adhesive layer, which is directly attached to the front surface of an image display glass plate of a plasma display,
The refractive index of the adhesive layer between the polyethylene terephthalate substrate and the functional layer, or between the functional layers, and when the refractive index difference between the two layers in contact with the adhesive is 0.10 or more, the refraction of each layer An optical filter characterized by being adjusted to be located in the middle of the rate,
(2) A multilayer optical filter having a polyethylene terephthalate substrate, a plurality of functional layers and an adhesive layer, which is directly attached to the front surface of an image display glass plate of a plasma display,
When the refractive index difference between the two layers in contact with the adhesive is less than 0.1, the refractive index of the adhesive layer interposed between the polyethylene terephthalate substrate and the functional layer or between the functional layers is less than 0.1. An optical filter characterized by being adjusted to an average value of refractive index within ± 0.05;
(3) The optical filter according to (1) or (2), wherein the adhesive layer contains 10 to 50% by mass of an acrylic adhesive component and metal compound fine particles having an average particle diameter for adjusting the refractive index of 5 to 200 nm. ,
(4) The optical filter according to any one of (1) to (3), wherein the adhesive layer is a pressure-sensitive adhesive layer.
(5) Said (1)-(4) which has an adhesive layer for affixing on the image display glass plate of a display on one surface of a plastic base material, and has a functional layer containing a plastic base material on the other surface. ) The optical filter according to any one of
(6) The optical filter according to any one of (1) to (5), wherein the functional layer includes an electromagnetic wave shielding layer, a near infrared absorption layer, and an antireflection layer,
(7) The optical layer according to (6), wherein the functional layer further includes a toning layer, a neon light absorption layer, and an antifouling layer, and (8) the plasma display panel and the front surface of the image display glass plate of the plasma display panel There is provided a plasma display comprising: the optical filter according to any one of (1) to (7), which is bonded to the substrate via the adhesive layer.

  According to the present invention, in an optical filter directly attached to the front surface of an image display glass plate of a PDP, an optical filter that can visually recognize the display of the PDP with high contrast and can be supplied at a low cost with a high productivity is used. A high-contrast PDP can be provided.

The optical filter of the present invention is a multilayer optical filter having a polyethylene terephthalate substrate, a plurality of functional layers and an adhesive layer, which is directly attached to the front surface of an image display glass plate of a plasma display,
The refractive index of the adhesive layer between the polyethylene terephthalate substrate and the functional layer, or between the functional layers, and when the refractive index difference between the two layers in contact with the adhesive is 0.10 or more, the refraction of each layer It is adjusted so that it is located in the middle of the refractive index, or when the difference in refractive index is less than 0.1, it is adjusted within the average value ± 0.05 of the refractive index of the two layers. It is an optical filter.
In the present invention, the functional layer means an electromagnetic wave shielding layer, a near infrared absorption layer, a color correction layer, an antireflection layer, an antiglare layer, an antifouling layer, a hard coat layer, and the like.
The plasma display of the present invention is a PDP comprising a plasma display panel and the optical filter of the present invention.
Hereinafter, the present invention will be described in detail with reference to the drawings.

[Example 1]
FIG. 1 is a cross-sectional view showing an example of an optical filter for plasma display according to the present invention. The optical filter 10 for plasma display is formed of a polyethylene terephthalate (hereinafter abbreviated as “PET”) base 11 and an adhesive layer 12, an electromagnetic wave shielding layer 13, and a flattened layer formed in order on one surface thereof. It has a toning adhesive layer 14 that also serves as a layer, a PET base material 15, a near infrared absorption layer 16, an adhesive layer 17 that also serves as a neon light absorption layer, a PET base material layer 18, and an antireflection layer 19, and the PET base material 11 has a pressure-sensitive adhesive layer 20 formed on the other surface of 11 for sticking this laminate to the display glass plate G of the PDP.
These layer structures are formed by forming the functional layers of the electromagnetic wave shielding layer member 13, the near-infrared absorbing layer 16, and the antireflection layer 19 on the PET base materials 11, 15, 18 and further coating the PET base material with an adhesive. Then, the adhesive layer 12, the toning adhesive layer 14, and the neon light absorbing adhesive layer 17 are directly formed, or a semi-cured adhesive that has already been prepared and sandwiched between release sheets is dry-laminated, This is achieved by preparing a functional layer for each PET substrate unit and laminating it.
The adhesive layer 20 for attaching the laminate as an optical filter to the image display glass plate G of the PDP may be formed by directly coating the PET substrate 11 with an adhesive, or the already formed peeling. A type of adhesive may be dry laminated.
The optical filter 10 of the present invention shown in FIG. 1 can be divided into two members. That is, an electromagnetic wave shielding member 1 having an PET layer 11, an adhesive layer 12 that is optionally provided, and an electromagnetic wave shielding layer 13, a PET substrate 15, and the PET substrate 15. The toning adhesive layer 14 provided on one side of the surface, the near infrared absorption layer 16 provided in order on the other side, the PET base material 18, and the PET base material 18 provided on one side The optical filter member 2 can be divided into a neon light absorbing layer (adhesive layer) 17 and a light reflection preventing layer 19 provided on the other surface.

As a PDP image display glass plate to which the optical filter of the present invention is directly attached as a front plate, a general PDP image display glass plate having a refractive index of about 1.517 is used.
The PET substrate used in the present invention has a refractive index of about 1.65. Polyethylene terephthalate is selected from the viewpoints of transparency, heat resistance, handleability, low cost due to mass production, and the thickness is about 12 μm to 300 μm from the viewpoint of workability. It is preferable that it is the range of these. If the thickness is within this range, it is too soft, there is no generation of stretching or wrinkles due to tension during processing, and continuous winding in each process is possible without reducing the flexibility of the film, And the workability at the time of laminating | stacking several PET base materials is not reduced significantly.

The PET substrate does not necessarily need to be colorless and transparent, and may be colored and transparent as long as the light transmittance does not extremely decrease.
Additives such as ultraviolet absorbers, fillers, plasticizers and antistatic agents can be appropriately added to the PET base material as desired.
As the PET base material, one that is usually stretched from the viewpoint of mechanical strength is used, but a uniaxially stretched or biaxially stretched sheet or film is more preferable from the viewpoint of mechanical strength.
Further, the PET base material does not necessarily have to be a single layer, and only the surface layer thereof may have a high-concentration weathering layer of an ultraviolet absorber.
Further, in some cases, as described in JP-A-11-116826, a near infrared absorbing dye and a dye such as a visible color absorbing dye for color tone correction are dispersed. It can also serve as an absorption functional layer.
The PET base material is appropriately subjected to known easy adhesion treatment such as corona discharge treatment, plasma treatment, ozone treatment, flame treatment, primer treatment, pre-heat treatment, dust removal treatment, vapor deposition treatment, alkali treatment, etc. May be.

(Adhesive layer)
Next, the adhesive layer interposed between the PET base material and the functional layer or between the functional layers, which is an essential layer in the optical filter of the present invention, will be described.
The adhesive layer is not particularly limited as long as it is a layer capable of bonding the PET base material and the functional layer or the functional layer, and various natural or synthetic resins. A heat or ionizing radiation curable resin can be applied.

Moreover, in this invention, it is especially preferable that it is an adhesive layer which is used for adhesion | attachment with the said optical filter member and an electromagnetic wave shielding member, and has fluidity | liquidity at the time of lamination | stacking. The fluidity mentioned here refers to the property of deforming or displacing indefinitely with little or no resilience against external force. For example, Newton viscosity such as water, dilatancy or thixotropic (non-Newton) viscosity, or creep deformability is comprehensively referred to.
However, after laminating the flat layer filled with the mesh opening of the electromagnetic wave shielding member and the continuous band-shaped optical filter member, that is, when adhering to the electromagnetic wave shielding member, the fluidity of the adhesive is not necessary, and rather the adhesive. The fluidity of the agent promotes the discoloration of the dye when the adhesive flows out from the laminated interface between the electromagnetic wave shielding member and the continuous band-shaped optical filter member or when a dye (colorant) is added to the adhesive layer. There is a case to do, is not preferable.

  As the adhesive layer having fluidity, it is sufficient that the adhesive layer has fluidity at the time of adhesion and lamination. For example, an adhesive layer made of a resin that has been fluidized (liquefied) by dissolving or dispersing in an adhesive or solvent, Even an adhesive layer composed of a natural rubber or synthetic resin that is fluid at room temperature without being dissolved or dispersed, or a syrup-type adhesive in which the polymer is dissolved in the reaction monomer Good. Further, it may be a hot-melt adhesive layer that is melted by applying an appropriate temperature and has fluidity. Further, it may be an adhesive layer containing a polymerization reactive monomer that is liquid at room temperature, and may be an adhesive layer that is cured by light and / or heat after lamination. Among them, as a method for reducing the fluidity of the adhesive layer, for example, a cross-linking agent is added to the adhesive layer in advance and bonded to the electromagnetic wave shielding member, and then the adhesive is cross-linked by heating, ultraviolet irradiation or the like. Examples of suitable methods include a polymerization method.

Among these, as the adhesive layer having fluidity used in the present invention, a pressure-sensitive adhesive layer is preferable.
Here, the pressure-sensitive adhesive is a kind of adhesive. Of the adhesives, only adhesiveness on the surface is obtained only by pressing moderately, usually lightly by hand, at the time of bonding. It can be glued.
In order to develop the adhesive strength of the pressure-sensitive adhesive, usually, physical energy or action such as heating, humidification, and radiation (ultraviolet ray, electron beam, etc.) irradiation is unnecessary, and chemical reaction such as polymerization reaction is not required.
Moreover, the pressure-sensitive adhesive can maintain the adhesive strength to the extent that it can be re-peeled even after bonding.
There is no restriction | limiting in particular as such an adhesive, It has moderate adhesiveness (adhesive force), transparency, and coating suitability from what is conventionally used as a well-known adhesive, and it is used in this invention. An optical filter that does not substantially change the transmission spectrum of the optical filter is appropriately selected.

  An acrylic adhesive is mentioned as an adhesive suitably used. The acrylic pressure-sensitive adhesive is a polymer containing at least a (meth) acrylic acid alkyl ester monomer. Generally, it is a copolymer of a (meth) acrylic acid alkyl ester monomer having an alkyl group having about 1 to 18 carbon atoms and a monomer having a carboxyl group. In the present invention, (meth) acrylic acid refers to acrylic acid and / or methacrylic acid.

Examples of (meth) acrylic acid alkyl ester monomers used here include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, sec-propyl (meth) acrylate, N-butyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, Examples thereof include n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, undecyl (meth) acrylate, and lauryl (meth) acrylate.
Moreover, the said (meth) acrylic-acid alkylester is normally copolymerized in the quantity of 30-99.5 mass% in acrylic adhesive.

  Moreover, as a monomer which has a carboxyl group which forms an acrylic adhesive, monomers containing a carboxyl group such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, monobutyl maleate and β-carboxyethyl acrylate are used. Can be mentioned.

  Furthermore, in addition to the above, the acrylic pressure-sensitive adhesive used in the present invention may be copolymerized with a monomer having another functional group within a range not impairing the properties of the acrylic pressure-sensitive adhesive. Examples of monomers having other functional groups include monomers containing hydroxyl groups such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and allyl alcohol; (meth) acrylamide, N-methyl Monomers containing amide groups such as (meth) acrylamide and N-ethyl (meth) acrylamide; Monomers containing amide groups and methylol groups such as N-methylol (meth) acrylamide and dimethylol (meth) acrylamide; Monomers having functional groups such as monomers containing amino groups such as (meth) acrylate, dimethylaminoethyl (meth) acrylate and vinylpyridine; epoxy group-containing monomers such as allyl glycidyl ether and (meth) acrylic acid glycidyl ether Can be mentioned. In addition to these, fluorine-substituted (meth) acrylic acid alkyl ester, (meth) acrylonitrile, and the like, vinyl group-containing aromatic compounds such as styrene and methylstyrene, vinyl acetate, and vinyl halide compounds can be used.

Furthermore, in the acrylic pressure-sensitive adhesive used in the present invention, in addition to the monomer having other functional groups as described above, another monomer having an ethylenic double bond can be used. Examples of monomers having an ethylenic double bond include diesters of α, β-unsaturated dibasic acids such as dibutyl maleate, dioctyl maleate and dibutyl fumarate; vinyl esters such as vinyl acetate and vinyl propionate. Vinyl ether; vinyl aromatic compounds such as styrene, α-methylstyrene and vinyl toluene; (meth) acrylonitrile and the like.
In addition to the monomer having an ethylenic double bond as described above, a compound having two or more ethylenic double bonds may be used in combination. Examples of such compounds include divinylbenzene, diallyl malate, diallyl phthalate, ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, methylene bis (meth) acrylamide, and the like.

Furthermore, in addition to the above-described monomers, monomers having an alkoxyalkyl chain can be used. Examples of alkoxyalkyl esters of (meth) acrylic acid include 2-methoxyethyl (meth) acrylate, methoxyethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, 3-methoxypropyl (meth) acrylate , 2-Methoxybutyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, 4-ethoxybutyl (meth) acrylate And so on.
Examples of commercially available acrylic pressure-sensitive adhesives include Nos. TU-41A, TD-06, and Nitto Denko's No. 591, no. 5915, no. 5919M, no. 595B, CS9621, LA-50, LA-100, HJ-9210, HJ-9150W, etc. are preferably used.

  In addition, the rubber-based pressure-sensitive adhesive has, as a main component, for example, natural rubber, polyisoprene rubber, polyisobutylene rubber, polybutadiene rubber, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, etc. What contains at least 1 sort (s) chosen from is used.

Moreover, it is preferable to mix | blend antioxidant with an adhesive bond layer. It is possible to prevent the electromagnetic wave shielding layer from being oxidized by the acid component contained in the adhesive at the interface between the adhesive layer and the electromagnetic wave shielding layer of the obtained optical filter and causing a color change.
Furthermore, a crosslinking agent such as an isocyanate compound, a tackifier, a silane coupling agent, a filler, and the like can be blended in the adhesive layer as desired.

In addition, in the optical filter of the present invention, in addition to the above adhesive, in consideration of the refractive index with the PET base material, for example, a polyester-based adhesive described in JP-A-2001-247834 may be used. it can.
The adhesive described in the publication includes 40 to 90% by mass of a polyester resin, 10 to 60% by mass of an epoxy resin, and an effective amount of a cationic photopolymerization initiator in the entire resin composition. The ratio of the alicyclic epoxy resin in the resin is 10 to 90% by mass.
Specific examples of the polyester-based resin include, for example, trade names “Byron” series and “Byronal” series manufactured by Toyobo Co., Ltd., trade names “Eritel” series manufactured by Unitika, and trade names manufactured by Dainippon Ink & Chemicals, Inc. "Spinodol" series, Takeda Pharmaceutical Co., Ltd. product name "Takelac" series, Kuraray Co., Ltd. product name "Kuraball" series, etc., and the polyester resin has an ester group in the molecule at the molecular end Since it has a hydroxyl group or a carboxyl group, it has high polarity and, for example, has excellent adhesion to highly polar materials such as PET, PVC, ABS, PEN, polycarbonate, and metal. Moreover, since it has crystallinity and high cohesive force, moderate cohesive force is provided to the adhesive composition before hardening.

  The glass transition temperature (Tg) of the polyester resin has a range of selection depending on the bonding temperature and is not particularly limited, but is generally preferably 100 ° C. or lower, more preferably 50 ° C. or lower. . If the Tg of the polyester-based resin exceeds 100 ° C., the cohesive strength of the polyester-based resin becomes too high, and the tackiness and initial adhesive strength of the adhesive composition are reduced, or it is necessary to bond at a high temperature. Although workability may be reduced, the cohesive force can be adjusted by an epoxy resin, which will be described later, so it is not uniquely determined.

  On the other hand, over time, the adhesive composition containing a polyester resin wets and spreads to the adherend interface, and the adhesion area increases. At this time, the molecules of the polyester-based resin flow to align the functional group having the highest affinity with the adherend, so that the adhesive force is improved over time. The adhesive composition has an advantage that it exhibits a very high adhesive force after curing.

  In addition, since the polyester resin is incorporated into a gel structure formed by curing of the epoxy resin and the molecular mobility is remarkably restricted, the cured adhesive composition exhibits a high cohesive force. This is because a functional group in the polyester resin, in particular, a hydroxyl group and an epoxy group in the epoxy resin are cationically polymerized and crosslinked.

  Examples of the epoxy resin used include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin; novolak type such as phenol novolac type epoxy resin and cresol novolac type epoxy resin. Epoxy resin; Alicyclic epoxy resin; Glycidyl ether type epoxy resin; Glycidylated amine type epoxy resin; Halogenated epoxy resin; or epoxy group containing glycidylated polyester, glycidylated polyurethane, glycidylated acrylic, etc. Examples include monomer or oligomer addition polymers. These epoxy resins may be used alone or in combination of two or more.

  Further, the epoxy resin may be a modified epoxy resin modified with another resin, if necessary, or a functional group into which a reactive functional group such as a radical polymerizable unsaturated bond is introduced. A group-introduced epoxy resin may be used.

  Examples of the modified epoxy resins and functional group-introduced epoxy resins include urethane-modified epoxy resins, polysulfide-modified epoxy resins, terminal carboxyl group-containing acrylonitrile-butadiene rubber (CTBN) -modified epoxy resins, and terminal amine group-containing acrylonitrile. -Butadiene rubber (ATBN) modified epoxy resin, crosslinked acrylonitrile-butadiene rubber (crosslinked NBR) particle dispersed epoxy resin, carboxyl group-containing crosslinked NBR particle dispersed epoxy resin, glycidyl group-containing crosslinked NBR particle dispersed epoxy resin, crosslinked acrylic Examples thereof include rubber particle-dispersed epoxy resins and chelate-modified epoxy resins. These modified epoxy resins and functional group-introduced epoxy resins may be used alone or in combination of two or more.

  Specific examples of the epoxy resin include, for example, a product name “Epicoat” series manufactured by Yuka Shell Epoxy, a product name “Epon” series manufactured by Shell Chemical, and a product name “Adeka Resin” series manufactured by Asahi Denka Kogyo Co., Ltd. And “Adekaoptomer” series, “Celoxide” series, “Cyclomer” series, “Epofriend” series and “Epolide” series manufactured by Daicel Chemical Industries.

  Among the epoxy resins, alicyclic epoxy resins such as 3,4-epoxycyclohexylmethyl are particularly preferably used. Specific examples of the alicyclic epoxy resin include, for example, a trade name “Celoxide” series manufactured by Daicel Chemical Industries, a trade name “Optomer KRM” series manufactured by Asahi Denka Kogyo Co., Ltd., and the like.

  The alicyclic epoxy resin has high cationic polymerizability, and forms a cured matrix faster than other epoxy resins. That is, when an alicyclic epoxy resin is used, a gel component (solvent insoluble component) is generated by a cured matrix immediately after irradiation with light having an active wavelength, and the cohesive force is increased. Accordingly, a certain initial cohesive force can be obtained even immediately after bonding, and for example, it is possible to suppress warping and deformation of the substrate, so that the parallel accuracy of the optical substrate and the electronic substrate is remarkably improved.

  The epoxy resin needs to contain 10 to 90% by mass of the alicyclic epoxy resin.

  When the content of the alicyclic epoxy resin in the epoxy resin is less than 10% by mass, the generation of the gel immediately after the light irradiation does not occur sufficiently, so that the initial cohesive force is not improved and the substrate warps. And it becomes difficult to suppress deformation. Conversely, when the content of the alicyclic epoxy resin in the epoxy resin exceeds 90% by mass, the reaction between the alicyclic epoxy resins proceeds first, and the functional group in the polyester resin, in particular, Since the reaction with the hydroxyl group does not proceed sufficiently, the polyester resin is difficult to be taken into the cured matrix. Therefore, the gel fraction after curing of the adhesive composition becomes low, the adhesive force and heat resistance become insufficient, or conversely, the gel fraction due to the reaction between the alicyclic epoxy resins immediately after light irradiation. Becomes too high, and the tackiness (tack) of the adhesive composition becomes insufficient. Moreover, since the molecular orientation of the polyester-based resin is hindered, the initial adhesive strength and the adhesive strength after curing are insufficient.

  The resin composition constituting the adhesive composition needs to contain 40 to 90% by mass of the polyester resin and 10 to 60% by mass of the epoxy resin.

  When the content of the polyester resin in the resin composition is less than 40% by mass or the content of the epoxy resin exceeds 60% by mass, the resulting adhesive composition or adhesive sheet is obtained. The elastic modulus after curing of the resin composition becomes too high, the peel adhesion and impact resistance to the adherend are insufficient, and conversely, the content of the polyester-based resin in the resin composition exceeds 90% by mass, or When the content of the epoxy resin is less than 10% by mass, the resulting adhesive composition or the adhesive sheet after curing does not sufficiently increase the crosslinking density, resulting in insufficient cohesive force and heat resistance. And deformation stress resistance is insufficient.

The adhesive layer may contain one or more near infrared absorbing dyes, ultraviolet absorbers, and / or neon light absorbing dyes as described above. By doing in this way, since the function of a plurality of functional layers can be shared by one layer, and this can be integrated with the adhesive layer, the total thickness, the number of steps, and the cost as an optical filter can be reduced. This is possible and preferable. In that case, the light transmittance in the wavelength region of 800 nm to 1100 nm is 20% or less, particularly 15% or less, and the light transmittance in the wavelength region of 560 to 630 nm is preferably 30% or less, particularly preferably 25% or less. .
The thickness of the adhesive layer is preferably 2 to 100 μm, more preferably 10 to 50 μm, and particularly preferably 15 to 35 μm. If the thickness of the adhesive layer is in the range of 2 to 100 μm, it is easy to apply uniformly in the adhesive application process, resulting in a stable adhesive strength and a short time required for curing. The improvement of property and the reduction of cost can be aimed at.
The adhesive layer is applied by a commonly used application method such as transfer printing, knife coater, roll coater, comma coater, gravure coater, etc., and heated and dried with infrared rays, hot air, steam, etc., and formed on one side of a PET substrate. Is done.

When the refractive index difference between the two layers in contact with the adhesive is 0.10 or more, the refractive index of the adhesive layer interposed between the PET base material and the functional layer is positioned between the refractive indexes of the respective layers. To adjust the refractive index of the adhesive layer interposed between the functional layers to within ± 0.05 of the average value of the two layers in contact with the adhesive, the transparent main component of the adhesive layer This can be achieved by selecting the resin (adhesive component) in consideration of the refractive index, or by adding metal compound-based fine particles having an average particle size for refractive index adjustment of preferably 500 nm or less to the adhesive component.
As the adhesive component, an acrylic component is particularly preferable as described above as the adhesive component in the case of using an adhesive.
As the metal compound-based fine particles, various compounds can be employed as long as they are insoluble in the acrylic adhesive component. Suitable metal compound-based fine particles include metal oxides and organometallic compounds. The metal oxide is at least one selected from the group consisting of Mg, Al, Si, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Zr, Pd, Ag, Sn, Pt, and Au. A metal oxide can be mentioned as a suitable example. More preferable metal oxides include Al ₂ O ₃ , TiO ₂ , SnO ₂ and ZnO.
Incidentally, the refractive index of the metal oxide is, for example, TiO ₂ (refractive index 2.2), ZrO ₂ (refractive index 2.0), ATO (refractive index 1.9), ITO (refractive index 1.9), It is about Sb ₂ O ₅ (refractive index 1.64).
The organometallic compound is at least one selected from the group consisting of Mg, Al, Si, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Zr, Pd, Ag, Sn, Pt, and Au. A metal alkoxide, the said metal acetylacetonate, etc. can be mentioned. Among the organometallic compounds, alkoxides of the metals are preferable, and titanium alkoxides are particularly preferable, and titanium tetramethoxide, titanium tetraethoxide, titanium tetrapropoxide, and titanium tetrabutoxide are particularly preferable.

The metal compound-based fine particles preferably have an average particle size of at most 500 nm, more preferably have an average particle size of 5 to 200 nm, and particularly preferably have a particle size of at most 100 nm.
If the average particle size of the metal compound-based fine particles is larger than 500 nm, light scattering may occur at the interface between the adhesive component and the metal compound-based fine particles, which may reduce transparency.
Further, when the average particle diameter is less than 5 nm, it is difficult to disperse in the adhesive component.

  Here, the average particle diameter of the metal compound-based fine particles can be measured using a commercially available particle size distribution measuring device, for example, a laser diffraction particle size distribution measuring device (SALD-70000, manufactured by Shimadzu Corporation).

  In addition, the metal compound-based fine particles are desirably surface-treated particles. The surface treatment is for the fine particles to improve the wettability with respect to the adhesive component and improve the dispersibility of the fine particles in the adhesive component. Examples of such surface treatment include treatment using a coupling agent. Examples of the coupling agent include silane coupling agents such as γ-chloropropyltrimethoxysilane and γ-glycidoxypropylmethyldimethoxysilane, aluminum coupling agents such as acetoalkoxyaluminum dipropionate, isopropyl triisostearoyl Examples thereof include titanate coupling agents such as titanate and isopropyltrioctanoyl titanate.

In the present invention, the content of the metal compound fine particles in the adhesive layers 14 and 17 is preferably in the range of 1 to 30% by mass. If the content of the metal compound-based fine particles is in the range of 1 to 30% by mass, the refractive index of the adhesive layers 14 and 17 can be adjusted effectively, and the light transmittance of the adhesive layers 14 and 17 does not decrease. In addition, the viscosity of the coating liquid does not increase extremely.
In addition, the uniform dispersion of the metal compound-based fine particles in the adhesive component can be performed by a known method such as roll kneading, stirring, ultrasonic dispersion, etc., if necessary, by adding a solvent.

(Electromagnetic wave shielding layer)
The optical filter 10 of the present invention can be an optical filter whose functional layer includes the electromagnetic wave shielding layer 13, the near infrared absorption layer 16, and the antireflection layer 19.
The electromagnetic wave shielding layer 13 is a layer having electrical conductivity and is responsible for the electromagnetic wave shielding function, and even if it is opaque, the electromagnetic wave shielding layer 13 has an opening in a mesh shape. It balances performance and light transmission. An example of the conductor layer 22 forming the mesh region 101 is shown in FIG. The conductor layer 22 forming the mesh region 101 has a mesh shape in which the openings 103 are densely arranged, and the mesh region is composed of the openings 103 and the line portions 104 forming a frame. .

  In the present invention, the material and forming method of the conductor layer forming the mesh-like region and the grounding region are not particularly limited, and various conductor layers in a conventionally known light-transmitting electromagnetic wave shielding layer can be used. It can be adopted as appropriate. In general, the conductor layer mainly includes a metal layer, and in addition to this, includes a conductive treatment layer as will be described later, and, in some cases, a conductive blackening layer and a rust prevention layer.

  The shape of the mesh is arbitrary and not particularly limited, but the shape of the opening is typically a square. Examples of the shape of the opening include a triangle such as a regular triangle, a square such as a square, a rectangle, a rhombus, and a trapezoid, a polygon such as a hexagon, a circle, and an ellipse. The mesh has a plurality of openings having these shapes, and the openings are usually line-shaped line portions having a uniform width. Usually, the openings and the openings have the same shape and the same size over the entire surface. As an example of a specific size, the width of the line portion 104 between the openings is referred to as a line width T as shown in FIG. 2 in terms of the aperture ratio and mesh invisibility, and is 25 μm or less, preferably 20 μm or less. It is preferable that However, it is preferable to secure at least 5 μm or more for the expression of the electromagnetic wave shielding effect and prevention of breakage. Further, the opening width of the opening is expressed by (line pitch P) − (line width T). In the present invention, it is 150 μm or more, preferably 200 μm or more. It is preferable from the point that air bubbles hardly remain in the opening during lamination. However, in order to exhibit electromagnetic wave shielding properties in the MHz to GHz band, the maximum is 3000 μm or less. Moreover, in Embodiment 1 of this invention, it is preferable that the thickness of the mesh area | region finally obtained, ie, the height H of the line part 104 between opening parts, shall be 5 micrometers or less. In such a case, even if the step of flattening the mesh surface is omitted in advance before the lamination with the optical filter, the electromagnetic wave shielding member and the optical filter member are bonded in the opening portion of the metal mesh at the time of lamination and bonding. This is because the agent layer is easy to enter uniformly and bubbles are unlikely to remain in the opening. In this case, it is possible to avoid the inconvenience that the cloudiness value (haze) of the optical filter due to light scattering of the bubbles increases, and it is possible to obtain an optical filter with high transparency with high production efficiency. In consideration of the electromagnetic wave shielding function so that the electric resistance value of the metal is not increased and the electromagnetic wave shielding effect is not easily lost, it is more preferable that the height of the line portion of the mesh region is 1 to 3 μm. . In addition, the height of the line part of a mesh-like area | region says the total thickness including all the thickness of the layer which forms the line part 104. FIG. For example, when the line part 104 is composed of only a conductor layer, the height of the line part is equal to the thickness of the conductor layer. For example, the line part has a conductor layer, a non-conductive blackening layer, and a non-conductive layer. In the case of the conductive rust preventive layer, the height of the line portion is the total thickness of the conductor layer, the nonconductive blackened layer, and the nonconductive rust preventive layer. Further, the bias angle of the mesh region (the angle formed between the mesh line portion and the outer periphery of the electromagnetic wave shielding layer) may be appropriately set to an angle at which moiré is difficult to occur in consideration of the pixel pitch of the display and the light emission characteristics. .

A method for preparing such an electromagnetic wave shielding sheet in which a conductive layer having a mesh-like region is laminated is not particularly limited, and examples thereof include the following four methods.
(1) A method in which conductive ink is printed in a pattern on the PET substrate 11 and metal plating is performed on the conductive ink layer (for example, JP 2000-13088 A).
(2) A method in which a conductive ink or a chemical plating catalyst-containing photosensitive coating solution is applied to the entire surface of the PET substrate 11 and the coating layer is made into a mesh by photolithography, followed by metal plating on the mesh ( For example, Sumitomo Osaka Cement Co., Ltd., New Materials Division, New Materials Research Institute, New Materials Research Group, “Photoresolvable Chemical Plating Catalyst”, [online], date not listed, Sumitomo Osaka Cement Co., Ltd. [2003] Search on January 7, a year], Internet <URL: http://www.socnb.com/product/hproduct/display.html>).
(3) After laminating the PET base material 11 and the metal foil with the adhesive layer 12, the metal foil is formed into a mesh by a photolithography method (for example, JP-A-11-145678).
(4) A PET thin film 11 is prepared by forming a metal thin film on one surface of the PET base 11 by sputtering or the like to form a conductive treatment layer, and forming a metal layer thereon by electrolytic plating. Then, the metal plating layer and the conductive treatment layer of the metal-plated PET base material 11 are formed into a mesh shape by a photolithography method (for example, Japanese Patent No. 3502979, Japanese Patent Application Laid-Open No. 2004-241761).

  Among them, in the present invention, in particular, transparency and mesh accuracy are excellent, display images can be visually recognized, and further, in the manufacturing process, there is little warping or mixing of bubbles, etc., and it can be manufactured with good yield and low cost in a short process. Therefore, it is particularly preferable to use the method (4). Then, the method to prepare the electromagnetic wave shielding sheet which has the conductor layer which forms the mesh-shaped area | region by the method of said (4) is demonstrated in detail.

  An example of an electromagnetic wave shielding layer formed by the method (4) above, in which a conductor layer forming a mesh-like region is laminated on one surface of the PET substrate 11, is shown in FIG. . 3 is a cross-sectional view taken along line AA and BB in FIG. 3A shows a cross section that crosses the opening, and the openings 103 and the lines 104 are alternately formed. FIG. 3B shows a cross section that runs through the line 104, and the line 104 made of the conductor layer 22. Are formed continuously. In FIG. 3, the conductor layer 22 includes a conductive treatment layer 23 and a metal plating layer 24 (hereinafter, both are collectively referred to as a metal layer).

(Formation of conductive treatment layer)
In the above method (4), the conductive treatment layer 23 is formed on the PET substrate 11 as described above by conducting a conductive treatment prior to metal electrolytic plating described later. As a method for the conductive treatment, a thin film of a known conductive material may be formed. Examples of the conductive material include metals such as gold, silver, copper, iron, nickel, and chromium, or alloys of these metals (for example, nickel-chrome alloys). Moreover, transparent metal oxides, such as a tin oxide, ITO, and ATO, may be sufficient. The conductive treatment may be a single layer or multiple layers (for example, a laminate of a nickel-chromium alloy and a copper layer), and these materials are formed by a known vacuum deposition method, sputtering method, electroless plating method, or the like. The conductive treatment layer 23 is used. The thickness of the conductive treatment layer 23 is preferably an extremely thin layer of about 0.001 to 1 μm, as long as necessary conductivity can be obtained at the time of plating.

(Metal plating layer)
A metal plating layer 24 is formed on the surface of the conductive treatment layer 23 by electrolytic plating to form a metal-plated PET substrate. As the material of the metal plating layer 24, for example, a metal having sufficient conductivity to shield electromagnetic waves, such as gold, silver, copper, iron, nickel, chromium, or an alloy containing these metals can be applied. The metal plating layer 24 may not be a simple substance but may be a multilayer, and copper or copper alloy is preferable from the viewpoint of easiness of electrolytic plating and conductivity. In the present invention, since the height of the line portion of the mesh region is preferably 1 to 3 μm as described above, the thickness of the metal plating layer 24 is preferably about 2 μm at the maximum. If the height of the line portion of the mesh region is less than this, the electric resistance value of the metal is increased and the electromagnetic wave shielding effect tends to be impaired. The level difference of the part becomes large, and bubbles tend to remain when the adhesive layer is laminated. In addition, the desired high-definition mesh shape cannot be obtained. As a result, the substantial aperture ratio is lowered, the light transmittance is lowered, the viewing angle is lowered, and the visibility of the image is lowered.

(Blackening layer)
In order to absorb the external light to the electromagnetic wave shielding layer 13 and improve the visibility of the image on the display, a blackening process is performed on the observation side of the conductor layer 22 forming the mesh-like region so that a contrast feeling is obtained. Is preferable. For this purpose, as shown in FIG. 4, at least one surface of the metal plating layer 24 is provided with a blackening layer 25A and / or 25B as necessary. The blackening layer is performed by roughening the surface of the metal plating layer 24, providing light absorption over the entire visible light spectrum (blackening), or using both in combination. Further, when a blackened layer is provided on the surface of the PET substrate 11, the metal plating layer 24 may be provided after conducting a conductive treatment on the PET substrate and providing the black plated layer (blackened layer) 25A. .

  As the blackening layers 25A and 25B, formation of metal oxides and metal sulfides and various methods can be applied. In the case of iron, it is usually exposed to steam at a temperature of about 450 to 470 ° C. for 10 to 20 minutes to form an oxide film (blackened film) of about 1 to 2 μm. An oxide film (blackened film) may be used. Further, in the case of copper, cathodic electrodeposition in which the cathode particles are attached by performing cathodic electrolysis in an electrolytic solution composed of sulfuric acid, copper sulfate, cobalt sulfate, and the like is preferable. By providing cationic particles, the particles become rougher and at the same time black is obtained. As the cationic particles, copper particles and alloy particles of copper and other metals can be applied, but copper-cobalt alloy particles are preferable. The average particle size of the cationic particles is preferably about 0.1 to 1 μm from the viewpoint of black density.

  A preferable black density of the blackened layer is 0.6 or more. In addition, the measurement method of black density was set to the density standard ANSIT as an observation viewing angle of 10 degrees, an observation light source D50, and an illumination type using GRETAG SPM100-11 (trade name, manufactured by Kimoto Co., Ltd.) of COLOR CONTROL SYSTEM. The specimen is measured after calibration. Further, the light reflectance of the blackened layer is preferably 5% or less. The light reflectance is measured using a haze meter HM150 (trade name, manufactured by Murakami Color Co., Ltd.) in accordance with JIS-K7105. In addition, instead of measuring the reflectance, the Y value of reflection may be expressed by a color difference meter. In this case, the Y value is preferably 10 or less.

(Rust prevention layer)
Further, a rust preventive layer 26 may be provided so as to cover at least one side of the metal plating layer 24 and, when a blackened layer is provided, to cover at least one side of the blackened layers 25A and / or 25B. preferable.
The rust prevention layer 26 is preferably provided at least on the blackening layer in order to prevent the rust prevention function and the blackening layer from dropping or deforming. As the rust prevention layer 26, an oxide of nickel, zinc, and / or copper, or a chromate treatment layer can be applied. The nickel, zinc, and / or copper oxide may be formed by a known plating method, and the thickness is about 0.001 to 1 μm, preferably 0.001 to 0.1 μm.

  The blackening layers 25A and 25B and the rust prevention layer 26 may be provided at least on the observation side, and the contrast is improved and the visibility of the image on the display is improved. Further, it may be provided on the other surface, that is, on the display surface side, and stray light generated from the display can be suppressed, so that the visibility of the image is further improved.

Next, the process of making the conductor layer 22 on the PET base material 11 provided as described above into a mesh shape by a photolithography method will be described.
First, a resist layer is provided on the conductor layer on the PET base material 11 prepared as described above, for example, the metal layer (metal plating layer) 24 surface on the PET base material 11, mesh-patterned, and covered with the resist layer. After removing the metal layer 24 which is not formed by etching, a mesh-like metal layer is formed by a so-called photolithography method in which the resist layer is removed.
Furthermore, existing equipment can be used, and by performing many of these manufacturing processes continuously, quality is high, production efficiency is high, yield is high, and production can be performed at low cost.

(Photolithography method)
A resist layer is provided in a mesh pattern on the conductor layer surface of the laminate, and a portion of the conductor layer not covered with the resist layer is removed by etching, and then the resist layer is removed to form a mesh. .

(masking)
First, the surface on the conductor layer side of the laminate of the PET base material 11 and the conductor layer 22 is meshed by photolithography to form the mesh region 101. Also in this step, it is preferable to process a roll-shaped laminate that is continuously wound in a band shape (referred to as winding processing, roll-to-roll processing). Masking, etching, and resist peeling are performed in a state where the laminate is stretched without looseness while being conveyed continuously or intermittently.

  First, in the masking, for example, a photosensitive resist is applied onto the conductor layer 22 forming the mesh-like region, dried, and then closely exposed with a predetermined pattern plate (photomask), developed with water, and hardened. Treat and bake. Note that either a negative type or a positive type of photosensitive resist can be used. When the photosensitive resist is a negative type, the mesh pattern of the pattern plate is a positive (positive image) with transparent line portions. When the photosensitive resist is positive, the mesh pattern of the pattern plate is a negative (negative image) with a transparent opening. Further, the exposure pattern is a desired pattern as an electromagnetic wave shielding sheet, and is composed of a pattern of a mesh area at a minimum. Further, as necessary, a grounding area pattern 102 is added to the outer periphery of the mesh area as shown in FIG.

  In the winding process, the resist coating is performed by continuously or intermittently transporting a belt-like laminate (a laminate of the PET base material 11 and the conductor layer 22), and the surface of the conductor layer 22 forming a mesh-like region. A resist such as casein, PVA, or gelatin is dipped (immersed), curtain coated, or poured. Moreover, a dry film resist may be used instead of application | coating, and workability | operativity can be improved. In the case of a casein resist, baking is performed at 200 to 300 ° C., but the lowest possible temperature is preferable in order to prevent warping of the laminate.

(etching)
Etching is performed after masking. As the etching solution used for the etching, a solution of ferric chloride or cupric chloride that can be easily circulated when etching is continuously performed is preferable. The etching is basically the same process as the equipment for manufacturing a shadow mask for a color TV cathode ray tube for etching a strip-like continuous steel material, particularly a thin plate having a thickness of about 20 to 80 μm. That is, the existing manufacturing equipment of the shadow mask can be diverted, and from masking to etching can be continuously produced continuously, which is extremely efficient. After etching, the substrate may be dried after washing with water, stripping the resist with an alkaline solution, and washing. Since the PET base material is exposed on the surface of the mesh opening thus formed, the transparency of the mesh opening is good.

  When the mesh-shaped electromagnetic wave shielding layer 13 is laminated on the PET substrate 11 via the adhesive layer 12, examples of the adhesive for the adhesive layer include acrylic, urethane, silicone, and rubber. , Vinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl butyral, phenol, epoxy, and petroleum rosin adhesives.

(Toning adhesive layer, flattening layer)
In the present invention, the near-infrared absorbing layer 16 is formed on one surface of the PET base material 15 and the toning adhesive layer 14 is formed on the other surface, and the toning adhesive layer 14 is a mesh after lamination. And a planarizing layer function for planarizing the region. From this point, the toning adhesive layer 14 is not particularly limited as long as it is transparent and has good adhesion to the mesh conductor layer and good adhesion to the adhesive in the next step. Particularly preferred is one that has good fluidity during lamination and does not leave bubbles or the like inside the mesh. The resin used as the adhesive constituting the toned adhesive layer is not particularly limited, and various natural or synthetic resins can be applied. From the durability, applicability, ease of flattening, flatness, etc. of the resin, Acrylic ultraviolet curable resins are preferred.
The toning adhesive layer 14 is prepared in a state where an adhesive containing a toning pigment is previously sandwiched between release films, and this is provided on the opposite side of the PET base material 15 on which the near-infrared absorbing layer is formed. You may laminate on the surface. Moreover, you may perform lamination | stacking at the process of laminating | stacking the whole optical filter.
The toning adhesive layer 14 can use a dye that absorbs near-infrared (about 800 nm to 1100 nm) absorption and a wavelength of 595 nm which is a Ne (neon) emission spectrum from the PDP. Specifically, the toning dye can be used so that the transmittance at a wavelength of 800 nm or more is 10% or less and the transmittance at a wavelength of 595 nm is 20% or less. Absorption of near infrared rays can reduce malfunctions of the infrared remote controller, and absorption of a wavelength of 595 nm can reduce the orange component and improve red purity. Then, the color tone of the toning adhesive layer 14 is adjusted to coordinates C = 0.301 and y = 0.311 on the CIE chromaticity diagram, the red component from the PDP is absorbed, and the color tone is corrected. To do. This toning means that another dye is used for the infrared absorbing dye to obtain the color tone of the coordinate value.

(Near-infrared absorbing layer)
The near-infrared absorbing layer 16 may be applied to the other surface of the PET base material 15 by containing a near-infrared absorbing dye in a binder resin. As the near-infrared absorbing dye, when an optical filter is applied to the front surface of a typical PDP, the near-infrared region generated when the PDP emits light using xenon gas discharge, that is, a wavelength of 800 nm to 1100 nm. It is preferable that the near-infrared transmittance in the band is 20% or less, more preferably 15% or less. At the same time, the near-infrared absorbing layer desirably has a sufficient light transmittance in the visible light region, that is, in the wavelength region of 380 nm to 780 nm.
Specific examples of near-infrared absorbing dyes include polymethine compounds, cyanine compounds, phthalocyanine compounds, naphthalocyanine compounds, naphthoquinone compounds, anthraquinone compounds, dithiol compounds, imonium compounds, diimonium compounds, and aminium. Compounds, pyrylium compounds, cerium compounds, squarylium compounds, copper complexes, nickel complexes, dithiol metal complexes organic near infrared absorbing dyes, tungsten oxide compounds, tin oxide, indium oxide, magnesium oxide, Titanium oxide, chromium oxide, zirconium oxide, nickel oxide, aluminum oxide, zinc oxide, iron oxide, ammonium oxide, lead oxide, bismuth oxide, lanthanum oxide, niobium oxide, tin-doped indium oxide (ITO), tantalum oxide, and Cesium oxide, zinc sulfide, furthermore, it can be used in combination PrB _6, LaB _6, CeB _6, NdB _6, CaB ₆ and the like such hexaboride inorganic near infrared absorbing dye, one, or two or more .
In addition, as the binder resin, a polyester resin, a polyurethane resin, an acrylic resin, a curing type using a reaction such as epoxy, acrylate, methacrylate, or isocyanate group that is cured by heat or ultraviolet rays can be applied.
Moreover, you may laminate | stack the commercial film (for example, Toyobo Co., Ltd. make, brand name No. 2832) which has a near-infrared absorption function directly with an adhesive agent, without using PET base material.
The thickness of the near infrared absorption layer is usually 5 to 30 μm.

(Antireflection layer)
Among the functional layers, the antireflection layer (also abbreviated as AR (Anti Reflection) layer) generally has a multilayer structure in which, for example, a low refractive index layer and a high refractive index layer are alternately laminated on the PET substrate 18. It can be formed by a dry method such as vapor deposition or sputtering, or by using a wet method such as coating. Note that silicon oxide, magnesium fluoride, fluorine-containing resin, or the like is used for the low refractive index layer, and titanium oxide, zinc sulfide, zirconium oxide, niobium oxide, or the like is used for the high refractive index layer.

(Neon light absorption layer)
Furthermore, the functional layer can be an optical filter having a neon light absorbing layer and an antifouling layer.
The neon light absorbing layer is installed to absorb neon light emitted from the PDP when the optical filter is used for a plasma display. The neon light absorption region has a wavelength of 550 to 640 nm, and is preferably designed so that the light transmittance at a wavelength of 550 nm is 50% or less. The neon light absorption layer can be formed by dispersing a dye conventionally used as a dye having an absorption maximum in a wavelength region of at least 550 to 640 nm in the binder resin exemplified in the description of the near infrared absorption layer. Specific examples of the dye include cyanine, oxonol, methine, subphthalocyanine or porphyrin.
Furthermore, the said pigment | dye which has a neon light absorption ability can be added to an adhesive agent, and it can serve as an adhesive bond layer and a neon light absorption layer.
Similarly to the above, when the refractive index of the adhesive layer 17 is intermediate between the near-infrared absorbing layer 17 and the PET base material 18 or within the average value ± 0.05 of the refractive indices of the two layers, External light reflection at the interface is suppressed, and the contrast is improved.

(Anti-fouling layer)
Of the functional layers, the antifouling layer is generally a water-repellent or oil-repellent coat, and a siloxane-based or fluorinated alkylsilyl compound can be applied. A fluorine-based or silicone-based resin used as a water-repellent paint can be preferably used. For example, when the low refractive index layer of the antireflection layer is formed of SiO ₂ , a fluorosilicate water-repellent paint is preferably used.

(Hard coat layer)
Among the functional layers, as the hard coat layer (abbreviated as HC (Hard Coat) layer), for example, polyfunctional (meth) acrylate such as polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, and the like. A prepolymer or a trifunctional or higher polyfunctional (meth) acrylate monomer such as trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate or the like alone or these monomers Alternatively, it can be formed as a coating film using an ionizing radiation curable resin selected from two or more prepolymers in combination.
Here, (meth) acrylate is a composite notation meaning acrylate or methacrylate.

(Anti-glare layer)
Among the functional layers, as an antiglare layer (also abbreviated as AG (Anti Glare) layer), a coating film formed by adding an inorganic filler such as silica in a resin binder, or a shaping sheet or a shaping plate, etc. By the used shaping process, it can be formed as a layer provided with fine irregularities for irregularly reflecting external light on the surface of the layer. As the resin of the resin binder, a curable acrylic resin, an ionizing radiation curable resin, or the like is preferably used in the same manner as the hard coat layer because surface strength is desired as the surface layer.

The present invention also provides a plasma display comprising a plasma display panel and the optical filter bonded to the front surface of the plasma display panel. In the bonding, the optical filter 10 is directly bonded as a front plate to the image display glass plate G of the plasma display by the adhesive layer 20. The pressure-sensitive adhesive layer 20 also has a function as an impact resistant layer.
Although there is no restriction | limiting in particular as a method to affix on the PDP display panel surface, Usually, a crimping | compression-bonding system is used.

[Shape and dimensions of optical filter]
Next, the shape and dimensions of the optical filter will be described.
First, the optical filter of the present invention can cover the entire image display area of the display to be applied so that the entire area of the image display area of the display to be applied is uniformly exhibited the function of the optical filter. Need to have different shapes and dimensions. Accordingly, first, the optical filter of the present invention has a shape and size that can cover all the portion 30 facing the image display region of the display of the electromagnetic wave shielding layer 13 shown in FIG.

Here, the image display area refers to an entire area inside the frame by the outer frame when viewed from the display side of the display, and is an area that is substantially inside the frame and displaying an image. If there is a black area (border) that does not substantially display an image outside, it is outside the image display area. However, it is uncomfortable that the appearance is different from that of the image display area as long as the black area is also seen from the viewpoint of practical use. Therefore, for convenience, it is preferable to handle the black area by including it in the image display area.
Further, the part of the electromagnetic wave shielding layer 13 facing the image display area of the display is made to face the image display area so as to cover the entire image display area of the applied display in the mesh-like area 101 of the electromagnetic wave shielding layer 13. An area is an area having substantially the same shape and size as the image display area. Usually, in order to facilitate alignment with the image display area of the display, it is often slightly (a few millimeters) larger than the image display area of the display.

  On the other hand, in the present invention, in order to secure the grounding portion on the electromagnetic wave shielding layer 13 at the same time that the single-wafer optical filter member 2 is laminated with the electromagnetic wave shielding layer member 1, the optical filter used in the present invention is the above-described electromagnetic wave shielding layer. It has a shape and a dimension capable of exposing at least a part of the 13 grounding regions. This grounding region originally does not require mesh formation, but a mesh may be formed. Further, the exposed portion may include a part of a mesh-like region present at the outer edge portion of the portion facing the image display region of the display.

  In order to have a shape and dimensions that allow at least a part of the grounding region of the electromagnetic wave shielding layer 13 to be exposed, one electromagnetic wave when the electromagnetic wave shielding member 1 is actually used as an optical filter for display. It cannot be made into the completely same shape and dimension as the whole area | region of the shielding member 1, and is covered with the whole area for one sheet of the electromagnetic wave shielding member 1, that is, from the whole area for one piece of the electromagnetic wave shielding member 1 Must also have small dimensions. However, as long as it is possible to expose at least a part of the grounding region, as described above, the image display region or the electromagnetic wave shielding layer 13 is substantially similar to the portion of the display that faces the display region. For example, as shown in FIG. 6A, only a part of the electromagnetic wave shielding member 1 overlaps the edge of the region of the electromagnetic wave shielding member 1 and only the exposed portion 40 is formed. Alternatively, as shown in FIG. 6B, for example, the shape may be such that the exposed portion 40 is hollowed out while the edge portions of one electromagnetic wave shielding member 1 are overlapped. The size of the optical filter member 2 is smaller than each region of the electromagnetic wave shielding member 1 by, for example, about 1 mm to 20 mm, more preferably about 1 mm to 10 mm, and particularly preferably about 2 mm to 5 mm. be able to.

  The single-wafer optical filter member 2 may be manufactured by laminating the functional layer of the optical filter member 2 thereon using a single-wafer PET substrate having a predetermined size and shape, It is preferable from the viewpoint of productivity efficiency that the optical filter member 2 produced in a roll shape is appropriately cut.

<Step of exposing the edge of the electromagnetic shielding layer>
In this process, the adhesive layer side of the single-wafer optical filter member 2 is directed to the electromagnetic wave shielding layer 13 side of the electromagnetic wave shielding member 1, and the single-wafer optical filter member 2 is a display in the electromagnetic wave shielding layer 13. The single-wafer optical filter member 2 is bonded and laminated to the electromagnetic wave shielding member 1 in a state of being positioned so as to face the portion directly opposite the image display area, and the grounding area of the electromagnetic wave shielding layer Expose at least a portion of

  A method for producing such an optical filter for display of the present invention will be specifically described with reference to the drawings. FIG. 7 is a process diagram showing an example of a bonding and laminating process in manufacturing a single wafer of the optical filter for display according to the present invention. FIG. 7A1 is a cross-sectional view showing a state in which the single-wafer optical filter member 2 is positioned so as to face the portion directly facing the image display area of the display in the electromagnetic wave shielding layer 13 of the electromagnetic wave shielding member 1. FIG. 7 (A2) is a plan view showing a state in which the positioning is performed. In FIG. 7, the electromagnetic wave shielding member 1 is shown as a single sheet, but the electromagnetic wave shielding member 1 may be laminated with the single-wafer optical filter member 2 while being in a continuous band shape.

  In this step, first, as shown in FIG. 7A1, the toning adhesive layer 14 side of the single-wafer optical filter member 2 is directed to the electromagnetic wave shielding layer 13 side of the electromagnetic wave shielding member 1, and As shown in FIG. 7 (A2), when the single-wafer optical filter member 2 uses the electromagnetic wave shielding member 1 or the continuous belt-like electromagnetic wave shielding member 1, the entire area 50 for one electromagnetic wave shielding member 1 is obtained. Positioning is performed directly on the portion 30 facing the image display area of the display so as to cover the entire portion 30 facing the image display area. When this alignment is performed, it is preferable to increase the positional accuracy by attaching a register mark on the electromagnetic wave shielding member 1 or using an optical sensor.

Next, as shown in FIG. 7 (B1), the adhesive layer 14 of the optical filter member 2 is adhered to and laminated on the electromagnetic wave shielding member 1, and the electromagnetic wave shielding layer is aligned. At least a part of the grounding region of the member 1 is exposed.
The exposed portion 40 is not particularly limited as long as it is appropriately designed so as to enable grounding, but a portion that does not affect image display around the four sides of the generally rectangular electromagnetic shielding member 1 is often provided in a frame shape. . Even if the entire periphery of the edge portion of the electromagnetic wave shielding member 1 is not exposed, only one side may be exposed, or one or several portions may be exposed.

  The optical filter of the present invention manufactured by the manufacturing method including the steps as described above has a step of removing another optical filter member 2 from the electromagnetic wave shielding member 1 for grounding the optical filter. In addition, the electromagnetic wave shielding layer can be exposed and grounded. Since there is no peeling and removing step that needs to be performed once for each display, mass production can be performed collectively and production efficiency is good.

  Particularly, as the electromagnetic wave shielding layer, the height of the line portion of the mesh-like region is 3 μm or less, the opening width of the mesh opening is 150 μm or more, and the mesh opening has no flattening layer coating. When using the optical filter member 2 having a fluid toning adhesive layer at the time of adhesion and lamination as the optical filter member 2 while using an electromagnetic wave shielding layer, the above-described mesh region flattening step is performed. It is unnecessary, and it is possible to reduce unnecessary materials and processes, and to obtain an optical filter having excellent transparency with high production efficiency.

The optical filter for display according to the present invention preferably has a high transparency, and preferably has a haze of 3 or less.
Here, haze means a value measured by a method according to JIS K7105-1981.

[Example 2]
FIG. 8 is a cross-sectional view showing another example of the optical filter for plasma display of the present invention. The optical filter 60 for plasma display includes a PET base material 11 and an adhesive layer 12, an electromagnetic wave shielding layer 13, a toning adhesive layer 31 that also serves as a flattening layer, a near-infrared absorbing layer, which are sequentially formed on one surface of the PET base material 11. And a neon light absorbing layer 32, a PET base material 33, and an antireflection layer 19, and an adhesive layer formed on the other surface of the base material 11 for attaching the laminate to a display glass plate of a PDP. 20.
In FIG. 8, the same reference numerals are used for the same components as those in FIG.
In the second embodiment, in comparison with the first embodiment, the electromagnetic wave shielding layer 13 is bonded to the copper foil with the adhesive layer 12 interposed, and one surface of the PET base material 33 absorbs near infrared rays. The layer and the neon light absorption layer 32 are formed, the antireflection layer 19 on the other surface is formed, and the number of layers is reduced by reducing the number of PET base materials and adhesive layers from the first embodiment. There is.
In the second embodiment, the adhesive layer 31 is interposed between the surface of the adhesive layer 12 and the electromagnetic wave shielding layer member 13 and the near-infrared absorbing layer and the neon light absorbing layer 32 without directly contacting the PET substrate. When the difference in refractive index between the refractive index of the PET base material 11 with the adhesive layer 12 and the refractive index of the near-infrared absorbing layer and the neon light absorbing layer 32 is 0.10 or more (1) Or (2) when the difference in refractive index is less than 0.1, the average value of the refractive indices of the two layers is within ± 0.05. Adjusted.
By adjusting the refractive index in this way, external light reflection is small and a PDP image can be visually recognized with high contrast.

Adjustment of the refractive index of the adhesive layer 31 may be performed in the same manner as in the first embodiment.
The near-infrared absorption layer and the neon light absorption layer 32 are formed on one surface of the PET substrate 33 for the near-infrared absorption dye and neon light absorption layer for the near-infrared absorption layer described in the functional layer in the first embodiment. Can be formed by dispersing the dye in a binder resin.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

Hereinafter, the present invention will be specifically described with reference to examples.
Example 1
(1) Manufacture of the electromagnetic wave shielding member 1 with an adhesive layer The electromagnetic wave shielding member 1 was produced as follows (refer FIG.3 and FIG.4).
A continuous belt-shaped uncolored transparent biaxially stretched polyethylene terephthalate film having a thickness of 100 μm and a polyester resin primer layer formed on one side was prepared as a PET substrate 11.
On the primer layer of this PET substrate, a nickel-chromium alloy layer having a thickness of 0.1 μm and a copper layer having a thickness of 0.2 μm (a part of the conductor layer) are sequentially provided by sputtering. A treatment layer 23 was obtained.
On the surface of the conductive treatment layer, a copper metal plating layer 24 having a thickness of 2.0 μm is provided by an electrolytic plating method using a copper sulfate bath directly without providing the blackening layer 25A in FIG. Both layers of the metal plating layer 24 were formed as the conductor layer 22 to produce a copper-clad laminate sheet in which the conductor layer was directly formed on the PET substrate.

  Next, a blackened layer 25 </ b> B was formed on the conductor layer 22. Specifically, a nickel plate is used for the anode, and the above copper-clad laminate sheet is immersed in a blackening plating bath made of a mixed aqueous solution of a nickel ammonium sulfate aqueous solution, a zinc sulfate aqueous solution and a sodium thiocyanate aqueous solution. A blackening layer 25B made of a nickel-zinc alloy is coated on the entire surface of the exposed conductor layer to form a conductor layer member (conductive treatment layer 23, metal plating layer 24). And a blackened layer 25B) were obtained.

Next, the conductor layer member of the laminated sheet is surrounded by the mesh-shaped region 101 including the opening 103 and the line portion 104 and the four circumferences of the mesh-shaped region 101 by etching using a photolithography method. A frame-shaped grounding region 102 was formed on the outer edge (see FIGS. 2, 3, and 5).
Specifically, using a production line for a color TV shadow mask, the etching was performed consistently from masking to etching on the continuous belt-like laminated sheet. That is, after applying a photosensitive etching resist to the entire surface of the conductor layer of the laminated sheet, a desired mesh pattern is closely exposed, developed, hardened, and baked on the area corresponding to the line portion of the mesh. After processing the resist layer into a pattern in which the resist layer remains and there is no resist layer on the area corresponding to the opening, the conductor layer and the blackened layer are etched away with an aqueous ferric chloride solution. A mesh-shaped opening was formed, and then water washing, resist peeling, washing, and drying were sequentially performed.

  The mesh shape of the mesh region is such that the line width of the linear portion where the opening is a square and a non-opening is 10 μm, the line interval (pitch) is 300 μm, the height of the line is 2.3 μm, rectangular When cut into single sheets, the bias angle defined as the minor angle with respect to the long side of the rectangle was 49 degrees. The mesh region 101 has a portion 30 (see FIG. 5) that faces the image display region of the display when the completed optical filter is mounted on the front surface of the image display device (display). At the periphery of the shaped region 101, when the optical filter member 2 is cut into a rectangular sheet, a pattern is formed so that a frame portion with a width of 15 mm without an opening is left on the outer periphery of the four sides as a grounding region 102. . Thus, the electromagnetic wave shielding member 1 without a planarizing layer was obtained.

On the other hand, the pressure-sensitive adhesive layer 20 to be attached to the display glass plate of the PDP was formed on the other surface of the PET substrate 11 of the electromagnetic wave shielding member 1 as follows.
First, in order to set the refractive index of the pressure-sensitive adhesive layer 20 to 1.58, which is an intermediate between the refractive index of the display glass plate 1.55 and the refractive index of 1.65 of the PET substrate, an acrylic pressure-sensitive adhesive component (manufactured by Soken Chemical Co., Ltd.). : SK2094), a pressure-sensitive adhesive coating solution in which 10% by mass of TiO ₂ having a refractive index of 2.0 and an average particle size of 10 nm was added as metal compound-based fine particles.
This is coated on a 100 μm-thick PET film (release film) whose surface is coated with a release agent, and the same PET film having a release layer formed on the surface is overlaid on the coating layer, and an ultraviolet curing device. And a continuous roll wound hardened pressure-sensitive adhesive layer having a thickness of 500 μm.
The thickness of the pressure-sensitive adhesive layer was set to 500 μm in consideration of the role as a shock absorbing layer when used for sticking to a display glass plate.
The refractive index of the pressure-sensitive adhesive layer 20 was measured with an Abbe refractometer by irradiating sodium D rays in an atmosphere at 25 ° C. The refractive index was 1.58.
While peeling the release film on the side of the pressure-sensitive adhesive layer in contact with the PET base material, the continuous band-shaped electromagnetic wave shielding member 1 is continuously supplied from the roll and pressed between the pair of rubber rollers at a linear pressure of 98 N / cm. An electromagnetic wave shielding member 1 with an agent layer was obtained.

(2) Manufacture of single wafer optical filter member 2 Next, the single wafer optical filter member 2 to be laminated on the electromagnetic wave shielding layer member 1 was prepared. As the layer configuration of the optical filter member 2, the antireflection layer 19, the neon light absorbing adhesive layer 17 (the adhesive layer 17 also serves as the neon light absorbing layer), the near infrared outside line absorbing layer 16, the toning adhesive layer 14 (adhesive layer 14 is also used as a toning layer). “/” Indicates that the left and right layers are laminated and integrated.

As the PET substrate, a Tetron film (trade name “HB type” manufactured by Teijin Ltd.), which is a transparent, biaxially stretched PET film having a thickness of 100 μm formed by kneading an ultraviolet absorber, is a PET substrate 15, 18 was used.
The antireflection layer was constituted by a material in which a high refractive index layer and a low refractive index layer were sequentially formed on the PET substrate layer 18.
Here, the high refractive index layer is a cured product having a thickness of 3 μm and a refractive index of 1.69 of a composition (trade name “KZ7973” manufactured by JSR Corporation) in which ultrafine zirconia particles are dispersed in an ultraviolet curable resin. Consists of layers.
The low refractive index resin layer is made of a cured product having a thickness of 100 nm and a refractive index of 1.41 made of a fluororesin-based ultraviolet curable resin (trade name “TM086” manufactured by JSR Corporation).

Further, the adhesive layer 17 is formed on the side opposite to the antireflection layer of the PET base material 18, and the neon light absorbing agent is added to the adhesive layer 17 to absorb the neon light absorption. Combined with layer.
A cyanine dye (trade name “TY-167” manufactured by Asahi Denka Kogyo Co., Ltd.) as a neon light absorber, and a diimonium dye (trade name “CIR1085” manufactured by Nippon Carlit Co., Ltd.), phthalocyanine as a near infrared absorber. And a phthalocyanine dye (manufactured by Nippon Shokubai Co., Ltd., trade name “IR14”) were added. Further, 10% by mass of metal compound fine particles TiO ₂ having a refractive index of 2.0 and an average particle diameter of 10 nm was added.

As an adhesive for the toning adhesive layer 14 and the neon light absorption layer 17, a low-flowing acrylic resin-based adhesive (manufacturer; manufactured by Nitto Denko Corporation, trade name: CS9621) is used. The thickness was 25 μm.
The refractive index of the toning adhesive layer 14 measured in the same manner as described above was 1.58, and the refractive index of the adhesive layer 17 was 1.54.
The portions where the PET base material on which the antireflection layer and the near infrared ray prevention layer are formed are overlapped and laminated with the adhesive layer 17 interposed therebetween, and the portion of the electromagnetic wave shielding layer 13 facing the image display region on the mesh 30 (rectangular shape), and the size was cut into large pieces by 4 mm both vertically and horizontally, and a single sheet optical filter member 2 was obtained.

(3) Manufacture of optical filter The obtained electromagnetic wave shielding member 1 with adhesive layer and the single-wafer optical filter member 2 are combined with the toned adhesive layer 14 of the electromagnetic wave shielding layer 13 as shown in FIG. The single-wafer optical filter member 2 covers the entire portion 30 facing the image display area of the mesh-shaped area 101 in the direction facing the mesh-shaped area 101, and the inner periphery of the grounding area 102. The side 2 mm is covered with the single-wafer optical filter member 2, while the outer peripheral side 13 mm of the grounding region 102 is uncovered and aligned so that the conductor layer is exposed, and then laminated to each other. did. The lamination conditions at this time are as follows: a vacuum pump is used for suction from the electromagnetic wave shielding member 1 side, and lamination is performed in a heated and pressurized state by blowing hot air at 80 ° C. from the single-wafer optical filter member 2 side (so-called autoclave To obtain an optical filter 10.

Comparative Example 1
In the adhesive layers 14 and 17 and the pressure-sensitive adhesive layer 20 of Example 1, an optical filter similar to that of Example 1 was obtained except that the refractive index was not adjusted without adding metal compound-based fine particles.

Example 2
(1) Manufacture of electromagnetic wave shielding member The electromagnetic wave shielding member 3 was produced as follows. First, as a metal foil used as the conductor layer 22, a continuous strip-shaped electrolytic copper foil having a thickness of 10 μm and having a blackened layer 25A made of copper-cobalt alloy particles formed on one surface was prepared.
Moreover, a continuous belt-shaped uncolored transparent biaxially stretched PET film having a thickness of 100 μm and a polyester resin primer layer formed on one side was prepared as a PET substrate 11.
Then, after the galvanization on both surfaces of the copper foil, a known chromate treatment was performed by a dipping method to form a rust preventive layer 26 on both surfaces.

  Next, on the surface of the blackened layer 25A on the surface of the blackened layer 25A, 12 parts by mass of a polyester polyurethane polyol having an average molecular weight of 30,000 as a main agent and 1 part by mass of a xylylene diisocyanate prepolymer as a curing agent. After being dry-laminated with a transparent two-component curable urethane resin-based adhesive consisting of the above, it is cured at 50 ° C. for 3 days, and a refractive index of 1. 7 μm between the copper foil (rust-proof layer) and the PET substrate 11 is obtained. A continuous strip-like copper-clad laminate sheet having 57 transparent adhesive layers 12 was obtained.

Next, the conductive layer and the blackened layer of the copper-laminated laminated sheet are etched by using a photolithography method, and the mesh region 101 including the opening 103 and the line portion 104, and the mesh region 101 are formed. A frame-shaped grounding region 102 was formed on the outer edge surrounding the four circumferences (see FIG. 5).
The etching process is the same as in Example 1. The height of the line portion of the mesh region is 10 μm, but the shape and dimensions of the other mesh regions are the same as those in the first embodiment.
Thus, the electromagnetic wave shielding member 3 of Example 2 without a planarizing layer was obtained.
Subsequently, the adhesive layer 20 for affixing on the display glass plate of PDP on the other surface of the PET base material 11 of the electromagnetic wave shielding member 3 was formed in the same manner as in Example 1.

Instead of the optical filter member 2 with the PET base material of Example 1 having two layers, the antireflection layer 19 is provided on one side of the PET base material 33, and the refractive index is 1.50. Except that a 9 μm thick (near infrared absorption layer + neon absorption layer) 32 is formed and an adhesive layer 31 that also serves as a color tone layer is formed on the (near infrared absorption layer + neon light absorption layer) 32 side, In the same manner as in Example 1, an optical filter member 4 was obtained (see FIG. 8).
The adhesive layer 31 was adjusted to have a refractive index of 1.52 to 1.54 by adding the same metal compound fine particles as in Example 1 to a thickness of 25 μm.
The electromagnetic wave shielding member 3 and the optical filter member 4 were laminated with the adhesive layer 31 interposed therebetween in the same manner as in Example 1 to obtain an optical filter 60.

Comparative Example 2
Example 2 was the same as Example 2 except that the adhesive layer 31 was laminated with an adhesive layer having a refractive index of 1.50 without adjusting the refractive index without adding metal compound-based fine particles. An optical filter was obtained.

  The optical filter of the said Example and the comparative example was affixed on the image display glass plate of 37 inch PDP (Hitachi company_made: W37P-H8000), and the following methods evaluated.

[Performance evaluation method]
Tables 1 and 2 collectively show the layer configuration, thickness, refractive index, and optical filter reflectance, transmittance, and photopic contrast in each example and comparative example.
(1) Refractive index It measured with the Abbe's refractometer at 25 degreeC using the sodium D line | wire.
(2) Contrast As shown in FIG. 9, a luminance meter (TOPCON bm-7, manufactured by Topcon Corporation) with a glass filter and a film filter at a position of 315 mm from the center of the PDP is arranged, and a fluorescent lamp Were placed at the distance shown in FIG. 9 and the contrast in the bright place was measured.
(3) Reflectance and transmittance The reflectance and transmittance were measured using a spectrophotometer (manufactured by Shimadzu Corporation: UV-3100PC).

As shown in Table 1, the bright spot contrast of Example 1 in which the refractive index of the adhesive layer and the pressure-sensitive adhesive layer was adjusted was 270, whereas in Comparative Example 1 in which the refractive index was not adjusted, the bright spot contrast was 250. In Example 1, an improvement in contrast of 8% was observed.
Moreover, as shown in Table 2, Example 2 in which the PET base material and the adhesive layer were further reduced from Example 1 to adjust the refractive index of the adhesive and the pressure-sensitive adhesive layer, and Comparative Example 2 in which the refractive index was not adjusted. , The photopic contrast was 273 and 263, respectively, and an improvement in photopic contrast was recognized by reducing the number of layers. In Example 2, it is recognized that the light-based contrast of the conventional base is improved by 9% when the configuration of Comparative Example 1 is used. In Comparative Example 1, a pressure-sensitive adhesive layer 20 having a thickness of 800 μm was also produced and evaluated.

  The optical filter directly attached to the front surface of the image display glass plate of the PDP of the present invention has two refractive indexes of an adhesive layer interposed between the PET base material and the functional layer or between the functional layers. Since adjustment was made in relation to the refractive index of the layer, reflection at the interface and functional layer of the PET base material was suppressed, contrast in the bright place was improved, PDP images could be viewed with high contrast, and a long roll shape Therefore, mass production can be performed while continuously supplying these materials, so that a highly functional optical filter can be provided at low cost.

Cross-sectional structure explanatory drawing of the optical filter of Embodiment 1 of this invention. It is a perspective view which shows an example of the mesh-like area | region 101 of the conductor layer of this invention. It is a figure which shows an example of the electromagnetic wave shielding layer used for this invention. It is a figure which shows another example of the electromagnetic wave shielding layer used for this invention. 5A is a plan view showing one unit of the electromagnetic wave shielding layer used in the present invention, and FIG. 5B is a cross-sectional view of an example of the electromagnetic wave shielding layer used in the present invention. It is a figure which shows an example of the exposed part of the electromagnetic wave shielding layer in this invention. It is a figure which shows an example of the adhesion | attachment in the sheet manufacture of the optical filter of this invention, and a lamination process. It is sectional structure explanatory drawing of the optical filter of Embodiment 2 of this invention. It is explanatory drawing of a contrast evaluation type | system | group.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 3 Electromagnetic wave shielding member 2, 4 Optical filter member 10, 60 Optical filter 11, 15, 18, 33 PET base material 12 Adhesive layer 13 Electromagnetic wave shielding layer 14, 31 Toning adhesive layer 16 Near-infrared absorption layer 17 Adhesion Agent layer (also neon light absorbing layer)
19 Antireflection layer (AR layer)
20 Adhesive layer (also impact-resistant layer)
DESCRIPTION OF SYMBOLS 21 Functional layer 22 Conductor layer 23 Conductive treatment layer 24 Metal plating layer 25 Blackening layer 26 Rust prevention layer 32 Near-infrared absorption layer and neon light absorption layer 101 Mesh area | region 40,102 Ground area 103 Opening part 104 Line part G PDP image display glass plate

Claims (8)

A multilayer optical filter having a polyethylene terephthalate substrate, a plurality of functional layers and an adhesive layer, which is directly attached to the front surface of an image display glass plate of a plasma display,
The refractive index of the adhesive layer between the polyethylene terephthalate substrate and the functional layer, or between the functional layers, and when the refractive index difference between the two layers in contact with the adhesive is 0.10 or more, the refraction of each layer An optical filter characterized by being adjusted so as to be located in the middle of the ratio. A multilayer optical filter having a polyethylene terephthalate substrate, a plurality of functional layers and an adhesive layer, which is directly attached to the front surface of an image display glass plate of a plasma display,
When the refractive index difference between the two layers in contact with the adhesive is less than 0.1, the refractive index of the adhesive layer interposed between the polyethylene terephthalate substrate and the functional layer or between the functional layers is less than 0.1. An optical filter adjusted to an average value of refractive index within ± 0.05.   The optical filter according to claim 1 or 2, wherein the adhesive layer contains 1 to 30% by mass of an acrylic adhesive component and metal compound-based fine particles having an average particle diameter for adjusting the refractive index of 5 to 200 nm.   The optical filter according to claim 1, wherein the adhesive layer is a pressure-sensitive adhesive layer.   It has an adhesive layer for affixing on the image display glass plate of a display on one surface of a plastic base material, and has a functional layer containing a plastic base material on the other surface. Optical filter.   The optical filter according to claim 1, wherein the functional layer has an electromagnetic wave shielding layer, a near infrared absorption layer, and an antireflection layer.   The optical filter according to claim 6, wherein the functional layer further includes a toning layer, a neon light absorption layer, and an antifouling layer.   A plasma display comprising: a plasma display panel; and the optical filter according to claim 1 bonded to the front surface of the image display glass plate of the plasma display panel via the adhesive layer.

Images