JP2000028825A - Ir absorbing filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a filter having high transmittance of light in a visible region, having no large absorption of a specified wavelength and having improved workability and productivity by specifying the transmittance of an IR absorbing layer and forming a metal mesh conductive layer having a specified or larger opening rate. SOLUTION: This IR absorbing filter has an IR absorbing layer on at least one surface of a transparent polymer film and has a metal mesh conductive layer having >=50% opening rate on the same or opposite surface of the IR absorbing layer. The IR absorbing layer has <=30% transmittance in a near IR ray region of 800 to 1100 nm wavelength, <=10% difference between the max. and min. transmittance in the visible region of 450 to 650 nm wavelength, and >=50% transmittance at 550 nm wavelength. By forming the metal mesh conductive layer, harmful electromagnetic waves emitted from a display can be removed. The dye to be used to satisfy this characteristics preferably contains two kinds of compds. selected from diimonium salt compds., fluorine- contg. phthalocyanine compds. and nickel complexes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical filter, and more particularly to an optical filter having a high transmittance in a visible light region and blocking infrared rays.

[0002]

2. Description of the Related Art Conventionally, the following materials have been widely used as a heat ray absorption filter, a video camera visibility correction filter, and the like. (1) Filters containing phosphoric acid-based glass and metal ions such as copper and iron (JP-A-60-235740;
(2) Layers having different refractive indices are laminated on a substrate, and an interference filter that transmits a specific wavelength by causing transmitted light to interfere (Japanese Patent Laid-Open Nos. 55-21091 and 59-184745).
(3) Acrylic resin filter containing copper ions in the copolymer (JP-A-6-324213) (4) Filter having a structure in which a pigment is dispersed in a binder resin (JP-A-57-21458, JP-A-57-21857) -19841
As for transparent electromagnetic wave absorption, various types of transparent electromagnetic wave absorption have been conventionally studied, and for example, there are the following ones. (5) Electromagnetic wave shielding material of the type using conductive fiber woven fabric (6) Electromagnetic wave shielding material of the type manufactured by etching a thin metal plate to form a mesh (7) Highly conductive metal such as silver, ITO or SnO An electromagnetic wave shielding material of a type in which a transparent conductive material such as ₂ is thinned by sputtering or a vacuum evaporation method, or the like. Further, a number of combinations of these have been proposed.

[0003]

The above-mentioned conventionally used infrared absorption filters have the following problems. In the above-mentioned method (1), absorption is sharp in the near-infrared region, and the infrared cutoff rate is very good.
Part of the red in the visible region is also greatly absorbed, and the transmitted color looks blue. In display applications, color balance is emphasized, and in such a case, it is difficult to use. Moreover, since it is glass, there is a problem in workability. In the case of the above-mentioned method (2), the optical characteristics can be freely designed, and a filter almost equivalent to the designed one can be manufactured.
For this reason, there is a disadvantage that the number of layers having a difference in the refractive index becomes extremely large and the manufacturing cost becomes high. In addition, when a large area is required, high-accuracy film thickness uniformity is required over the entire area, and manufacturing is difficult.

In the case of the method (3), the workability of the method (1) is improved. However, similar to the method (1), although there is a steep absorption characteristic, the problem that the red portion also absorbs and the filter looks blue remains unchanged.

In the method (4), a phthalocyanine-based compound, a nickel complex-based compound, an azo compound,
Many pigments such as polymethine, diphenylmethane, triphenylmethane, and quinone are used.
However, each alone has insufficient absorption or
There are problems such as absorption of a specific wavelength in the visible region. Furthermore, if the filter is left under high temperature or humidification for a long time, there is a problem that the decomposition and oxidation of the dye occur, absorption in the visible region occurs, and absorption in the infrared region disappears. .

Further, even when the above (1) to (4) are combined with (5) to (7) as electromagnetic wave absorption, the above-mentioned obstacles are not particularly improved.

[0007]

SUMMARY OF THE INVENTION The present invention has an absorption in the near-infrared region, a high light transmittance in the visible region, and does not have a large absorption of a specific wavelength in the visible region. The object of the present invention is to provide a near-infrared absorption filter having good productivity and productivity. That is, according to the present invention, at least one surface of the transparent polymer film has a transmittance of 30% or less in a near infrared region of a wavelength of 800 nm to 1100 nm and a wavelength of 450 nm to 650 nm.
The difference between the maximum and minimum transmittance in the visible region of m is 10%
And an infrared absorbing layer having a transmittance at a wavelength of 550 nm of 50% or more, and a metal mesh conductive layer having an aperture ratio of 50% or more on the same surface as the infrared absorbing layer or on the opposite surface. This is an infrared absorption filter characterized in that:

In the present invention, the wavelength is from 800 nm to 1100 nm.
It is essential that the transmittance in the near infrared region is 30% or less. Due to the low transmittance in this region, when used for a plasma display or the like, unnecessary infrared rays radiated from the display can be absorbed and malfunction of a remote controller using infrared rays can be prevented. Further, in the present invention, it is essential that the difference between the maximum value and the minimum value of the transmittance in the visible region of wavelengths from 450 nm to 650 nm is within 10%. When the transmittance difference between the wavelengths of 450 nm and 650 nm is within this range, the color tone becomes gray, and when placed in front of the display, the color tone emitted from the display can be expressed without change.

Further, according to the present invention, the transmittance at a wavelength of 550 nm is
50% or more is required. The transmittance in the wavelength region is 50%
If it is below, it will be a very dark display if it is installed in front of the display.

In order to satisfy the above-mentioned characteristics, the dye used in the present invention preferably contains at least any two of a diimonium salt compound, a fluorine-containing phthalocyanine compound and a nickel complex. The mixing ratio of the dye is preferably in the range of 0.5 to 0.01 part by weight for the fluorinated phthalocyanine compound and 1 to 0 part by weight for the nickel complex compound per part by weight of the diimonium salt compound.

In the present invention, it is preferable that an infrared absorbing dye is dispersed in a polymer and further coated on a transparent substrate. By adopting such a configuration, the production becomes simple and it is possible to cope with the production of small lots.
Further, the polymer for dispersing the dye according to the present invention preferably has a glass transition temperature that is higher than or equal to the assumed guaranteed temperature at which the filter of the present invention is used. Thereby, the stability of the dye is improved.

The infrared-absorbing dye used in the present invention is not particularly limited, but the following may be mentioned as an example. Nippon Kayaku Kayasorb IRG
-022, IRG-023, ExcolorIR manufactured by Nippon Shokubai Co., Ltd.
1, IR2, IR3, IR4, Mitsui Chemicals SIR-128, SIR-13
0, SIR-132, SIR-159, etc., but the above-mentioned infrared absorbing dye is only an example and is not particularly limited.

In the present invention, the transparent substrate used for coating the substrate with a polymer in which an infrared absorbing dye is dispersed is not particularly limited, but polyester, acrylic, cellulose, polyethylene Examples thereof include a resin, a polypropylene, a polyolefin, a polyvinyl chloride, a polycarbonate, a phenol, and a urethane resin, and a polyester resin is particularly preferable from the viewpoint of dispersion stability, environmental load, and the like.

The infrared absorbing filter of the present invention preferably contains a UV absorber for the purpose of improving light resistance. Furthermore, in the present invention, in order to impart weather resistance and solvent resistance, a polymer dispersing an infrared absorbing dye,
Crosslinking may be performed using a crosslinking agent.

In the present invention, it is essential that a metal mesh conductive layer is provided on the same surface as the infrared absorbing layer or on the opposite surface. This makes it possible to remove harmful electromagnetic waves emitted from the display. As the metal mesh used in the present invention, a metal foil having a high electrical conductivity is subjected to an etching treatment to form a mesh,
A woven mesh using metal fibers or a fiber in which a metal is attached to the surface of a polymer fiber by plating or the like may be used. When the aperture ratio of the mesh used for the electromagnetic wave absorbing layer is taken into account when used for display,
50% is preferred.

The metal used for the electromagnetic wave absorbing layer may be any metal as long as it has high electric conductivity and good stability, but is not particularly limited. From the viewpoint of workability and cost, copper is preferable. , Nickel and tungsten are good. Further, in the infrared absorbing filter of the present invention, a hard coat treatment layer (HC) may be provided on the outermost layer to prevent damage. As the hard coat treatment layer (HC), polyester resin, urethane resin, acrylic resin,
It is preferable to use a crosslinked resin cured material layer in which a curable resin such as a melamine resin, an epoxy resin, a silicon resin, and a polyimide resin is used alone or as a mixture.

The thickness of the hard coat treatment layer (HC) is as follows:
The range is preferably 1 to 50 μm, more preferably 2 to 50 μm.
3030 μm. When the thickness is less than 1 μm, the function of the hard coat treatment is not sufficiently exhibited, and when the thickness exceeds 50 μm, the speed of resin coating becomes extremely slow, and it is difficult to obtain good results in terms of productivity.

As a method of laminating the hard coat treatment layer (HC), the above resin is applied to the surface of the transparent conductive film opposite to the surface on which the transparent conductive thin film is provided by a gravure method, a reverse method, a die method or the like. After the coating, the composition is cured by applying energy such as heat, ultraviolet rays, and electron beams.

The infrared absorbing filter of the present invention may be provided with an anti-glare treatment layer (AG) as the outermost layer in order to improve the visibility when used for a display or the like. Anti-glare treatment layer (A
G) is to coat a curable resin, dry and form irregularities on the surface with an embossing roll, and then cure by applying energy such as heat, ultraviolet rays, and electron beams. The curable resin is preferably a single or mixed polyester resin, urethane resin, acrylic resin, melamine resin, epoxy resin, silicon resin, polyimide resin, or the like.

Further, in order to further improve the transmittance of visible light when the infrared absorption filter of the present invention is used for a display, an antireflection treatment layer (AR) may be provided on the outermost layer. It is preferable that a material having a refractive index different from that of the plastic film be a single layer or a laminate of two or more layers in the antireflection treatment layer (AR). In the case of a single-layer structure, it is preferable to use a material having a smaller refractive index than the plastic film. In the case of a multilayer structure of two or more layers, a material having a higher refractive index than the plastic film is used for a layer adjacent to the plastic film, and a material having a lower refractive index is used for a layer above the plastic film. Good to choose. As a material constituting such a reflection preventing treatment layer (AR), is not particularly limited as far as it satisfies the relation of the refractive index of the even inorganic materials in organic materials, for _{example, CaF 2, MgF 2, NaAlF} 4, SiO ₂ , ThF ₄ , ZrO ₂ , Nd ₂ O ₃ , Sn
It is preferable to use a dielectric such as O ₂ , TiO ₂ , CeO ₂ , ZnS, and In ₂ O ₃ .

The antireflection treatment layer (AR) may be a dry coating process such as a vacuum deposition method, a sputtering method, a CVD method, an ion plating method, or a wet coating process such as a gravure method, a reverse method, or a die method.

Further, the hard coat treatment layer (HC),
Prior to lamination of the anti-glare treatment layer (AG) and the anti-reflection treatment layer (AR), corona discharge treatment, plasma treatment,
Known processes such as a sputter etching process, an electron beam irradiation process, an ultraviolet irradiation process, a primer process, and an easy adhesion process may be performed.

Example 1 A base polyester serving as a dispersion medium was produced in the following manner. In an autoclave equipped with a thermometer and a stirrer, 136 parts by weight of dimethyl terephthalate, 58 parts by weight of dimethyl isophthalate 96 parts by weight of ethylene glycol, 137 parts by weight of tricyclodecane dimethanol 0.09 part by weight of antimony trioxide The part was charged and heated at 170 to 220 ° C. for 180 minutes to perform a transesterification reaction. Next, the temperature of the reaction system was raised to 245 ° C., and the reaction was continued for 180 minutes at a system pressure of 1 to 10 mmHg, thereby obtaining a copolymerized polyester resin (A1). The intrinsic viscosity of the copolymerized polyester resin (A1) is
0.4, glass transition temperature 90 ° C. The copolymer composition ratio by NMR analysis was 71 mol% of terephthalic acid and 29 mol% of isophthalic acid with respect to the acid component, 28 mol% of ethylene glycol with respect to the alcohol component, and 72 mol% of tricyclodecane dimethanol.

Next, an infrared absorbing dye, a prepared resin and a solvent having the composition shown in Table 1 were placed in a flask, and the mixture was stirred while heating to dissolve the dye and the binder resin. Further, the dissolved resin is applied to a highly transparent polyester film substrate (Cosmo Shine A410 manufactured by Toyobo Co., Ltd.).
0) was coated using an applicator having a gap of 100 μm, and dried at a drying temperature of about 90 ° C. for 1 hour. At this time, the coating thickness was about 25 μm. The color of the obtained infrared absorbing film was dark gray visually. FIG. 1 shows the spectral characteristics. FIG.
As shown in Fig. 7, a film having a flat absorption in a visible region from a wavelength of 400 nm to 650 nm and having a sharp absorption at a wavelength of 700 nm or more was obtained. The obtained film was allowed to stand in an atmosphere of 60 ° C. and 95% for 500 hours, and the spectral characteristics were measured again. The result was as shown in FIG. Also,
When the obtained film was arranged on the front surface of a plasma display or the like, there was no change in color, the contrast was improved, and the emission of near-infrared rays was reduced.

[0025]

[Table 1]

Example 2 A hard coat treatment layer (HC) was provided on the surface of the transparent polyester film opposite to the infrared absorbing layer produced in Example 1. As a hard coating agent, an ultraviolet curable resin composition obtained by adding 4 parts of benzophenone to 100 parts of an epoxy acrylic resin is used. A film is formed by a bar coating method, preliminarily dried at 80 ° C. for 5 minutes, and irradiated with ultraviolet light of 500 mJ / cm ² And cured. The thickness after curing is 5 μm. Next, a 9μm thick copper foil
Pasted on top of the infrared absorption layer via UV curing adhesive,
The laminated copper foil was patterned using a photoresist and subjected to an etching treatment to form an electromagnetic wave shielding layer. At this time, the copper foil line width was about 15 μm, the pitch was 115 μm, and the aperture ratio was 75%.

FIG. 3 shows the spectral characteristics of the filter in which the hard coat and the electromagnetic wave shielding layer are formed together with the infrared absorbing layer as described above. As shown in the figure, it was found that the filter absorbs near infrared rays, has a gray color tone, and has high visible light transmittance while absorbing electromagnetic waves. The obtained film was placed in a 60 ° C. 95% atmosphere for 500 hours.
When left to stand and the spectral characteristics were measured again, a slight color change was observed, but the near-infrared absorption characteristics were maintained. Also,
When the obtained film was disposed on the front surface of a plasma display or the like, there was no change in color, the contrast was improved, and the emission of near-infrared rays and the emission of electromagnetic waves were reduced.

Comparative Example 1 An infrared-absorbing dye, a binder resin and a solvent having a composition as shown in Table 2 were used in a flask using Toyobo Byron RV200 (specific gravity 1.26, glass transition temperature 67 ° C.) as a base polymer. The mixture was stirred while heating to dissolve the dye and the binder resin. Next, the melted resin was coated on a highly transparent polyester film substrate (Cosmoshine A4100 manufactured by Toyobo Co., Ltd.) using an applicator having a gap of 100 μm, and dried at a drying temperature of about 90 ° C. for 1 hour. The coating thickness was about 25 μm. The obtained infrared absorbing film had a visual coloration of brown. FIG. 4 shows the spectral characteristics. As shown in FIG.
An infrared absorbing film having a mountain-like characteristic having a peak at about 550 nm in the visible region up to nm was obtained.
The obtained film was left for 500 hours in an atmosphere of 60 ° C. and 95%, and the spectral characteristics were measured again. As a result, absorption in the near infrared region was lost. Also, the appearance had changed to green. In addition, when the obtained film was placed on the front surface of a plasma display or the like, the color balance was lost, and the color became greenish.

Comparative Example 2 A hard coat treatment layer (HC) was provided on the surface of the transparent polyester film opposite to the infrared absorbing layer produced in Comparative Example 1. As a hard coating agent, an ultraviolet curable resin composition obtained by adding 4 parts of benzophenone to 100 parts of an epoxy acrylic resin is used. A film is formed by a bar coating method, preliminarily dried at 80 ° C. for 5 minutes, and irradiated with ultraviolet light of 500 mJ / cm ² And cured. The thickness after curing is 5 μm. Next, a 9μm thick copper foil
Pasted on top of the infrared absorption layer via UV curing adhesive,
The laminated copper foil was patterned using a photoresist and subjected to an etching treatment to form an electromagnetic wave shielding layer. At this time, the copper foil line width was about 15 μm, the pitch was 115 μm, and the aperture ratio was 75%. FIG. 5 shows the spectral characteristics of the filter in which the hard coat and the electromagnetic wave shielding layer were formed together with the infrared absorption layer as described above. As shown in the figure, the filter absorbs near-infrared rays and electromagnetic waves, but has a greenish color tone.
In addition, the obtained film was placed in a 60 ° C. 95% atmosphere for 500 hours.
After standing for a while, the spectral characteristics were measured again. As a result, the near-infrared absorption characteristics were lost.

[0030]

[Table 2]

[Brief description of the drawings]

FIG. 1 shows the spectral characteristics of an infrared absorption filter obtained in Example 1.

FIG. 2 shows spectral characteristics of an infrared absorption spectrum obtained in Example 1 after a durability test.

FIG. 3 shows the spectral characteristics of the infrared absorption filter obtained in Example 2.

FIG. 4 shows the spectral characteristics of the infrared absorption filter obtained in Comparative Example 1.

FIG. 5 shows the spectral characteristics of the infrared absorption filter obtained in Comparative Example 2.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yozo Yamada 2-1-1 Katata, Otsu-shi, Shiga F-term in Toyobo Co., Ltd. General Research Laboratory 2H048 CA04 CA12 CA19 CA24 CA29

Claims (9)

[Claims] (1) a transparent polymer film having at least one surface having a transmittance in the near infrared region of a wavelength of 800 nm to 1100 nm of 30 nm;
% Or less, and the difference between the maximum value and the minimum value of the transmittance in the visible range from 450 nm to 650 nm is within 10%.
It has an infrared absorbing layer having a transmittance of 50% or more at 550 nm and a metal mesh conductive layer having an aperture ratio of 50% or more on the same surface as the infrared absorbing layer or on the opposite surface. Infrared absorption filter. 2. The infrared absorbing filter according to claim 1, wherein the infrared absorbing layer contains at least any one of a diimonium salt compound, a fluorine-containing phthalocyanine compound and a nickel complex as an infrared absorbing dye. . 3. The infrared absorbing layer according to claim 1, wherein the compounding ratio of the dye is 0.5 to 0.01 part by weight per 1 part by weight of the diimmonium salt compound,
In the case of a nickel complex compound, the amount is 1 to 0 parts by weight. 4. An infrared absorbing filter according to claim 1, wherein the dispersion medium of the dye in the infrared absorbing layer is a polyester resin. 5. An infrared absorption filter, wherein the transparent substrate according to claim 1 is a polyester film. 6. The polymer according to claim 1, wherein the glass transition temperature of the polymer used as a dispersion medium for dispersing the dye is equal to or higher than the guaranteed use temperature of a device using the filter. Infrared absorption filter. 7. An infrared absorbing film according to claim 1, further comprising an antireflection layer as an outermost layer. 8. An infrared absorbing film according to claim 1, which has an antiglare layer as an outermost layer. 9. A plasma display filter using any one of claims 1 to 7.