JP2000028826A - 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 specified wavelength and having improved workability and productivity by specifying the transmittance of an IR absorbing layer and forming a transparent conductive layer on the same or opposite face of the IR absorbing layer. SOLUTION: This IR absorbing filter has an IR absorbing layer on at least one surface of a transparent polymer film and has a transparent conductive layer on the same or opposite face of the IR absorbing layer. The IR absorbing layer has <=30% transmittance in the 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 transparent conductive layer, harmful electromagnetic waves emitted from a display can be removed. The dye to be used to satisfy the 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 a 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 maximum transmittance of a visible region of a wavelength of 450 nm to 650 nm. A difference between the value and the minimum value is within 10%, and an infrared absorption layer having a transmittance at a wavelength of 550 nm of 50% or more, and a transparent conductive layer on the same surface as the infrared absorption layer or on the opposite surface. This is an infrared absorption filter characterized in that:

In the present invention, it is essential that the transmittance in the near-infrared region of wavelengths from 800 nm to 1100 nm be 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. 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 the wavelength of 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 properties, the dye used in the present invention preferably contains at least any two of a diimonium salt compound, a fluorinated 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 this is 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, it is preferable that the polymer in which the dye is dispersed in the present invention has a glass transition temperature that is equal to or higher than the 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 examples thereof include the following. Nippon Kayaku Kayasorb IRG
-022, IRG-023, Excolor IR 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 the 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 transparent 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. Used in the present invention,
The transparent conductive layer may be any conductive film, but preferably,
Desirably, it is a metal oxide. Thereby, higher visible light transmittance can be obtained. Further, in the present invention, when it is desired to improve the conductivity of the transparent conductive layer, the transparent conductive layer preferably has a repeating structure of three or more layers of metal oxide / metal / metal oxide. By forming the metal into a multilayer, conductivity can be obtained while maintaining high visible light transmittance.

Used in the present invention. The metal oxide may be any metal oxide as long as it has electrical conductivity and visible light transmittance. Examples include tin oxide, indium oxide, indium tin oxide, zinc oxide, titanium oxide, bismuth oxide, and the like. The above is an example, and there is no particular limitation. The metal layer used in the present invention is preferably made of gold, silver or a compound containing them from the viewpoint of conductivity.

Further, when the conductive layer of the present invention is multilayered,
When the number of repeating layers is three, the thickness of the silver layer is preferably 5
0 to 200 °, more preferably 50 to 100 °. When the film thickness is thicker than this, the light transmittance decreases, and when the film thickness is thinner, the resistance value increases. Further, the thickness of the metal oxide layer is preferably from 100 to 100
0 °, more preferably 100 to 500 °. If it is thicker than this thickness, it will be colored and the color will change,
If it is thin, the resistance value will increase. Further, when three or more layers are formed, for example, when five layers such as metal oxide / silver / metal oxide / silver / metal oxide are used, the thickness of the central metal oxide is It is preferable that the thickness be larger than the thickness of the oxide layer. By doing so, the light transmittance of the entire multilayer film is improved.

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), a curable resin such as a polyester resin, a urethane resin, an acrylic resin, a melamine resin, an epoxy resin, a silicon resin, and a polyimide resin is used alone or as a mixture. A cured resin layer is preferred.

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 coated on 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.

Further, 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 visibility when used in 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, the infrared absorption filter of the present invention is
Further improves visible light transmission when used for spraying
To provide an anti-reflection treatment layer (AR) on the outermost layer
Good. This anti-reflective coating (AR) has a plastic film
A single layer of material with a refractive index different from that of the film
Preferably, two or more layers are stacked. Single layer structure
Has a lower refractive index than plastic film
It is preferable to use a material. In addition, a multilayer structure of two or more layers
If the plastic film is adjacent,
Use a material with a higher refractive index than tic film
Material with a lower refractive index
It is better to choose a fee. Such an anti-reflection treatment layer (AR)
Regarding the constituent materials, both organic and inorganic materials
Is not particularly limited as long as the refractive index relationship is satisfied.
If, CaF_Two, MgF_Two, NaAlF_Four, SiO_Two, ThF _Four, ZrO_Two, Nd_TwoO_Three, Sn
O_Two, TiO_Two, CeO_Two, ZnS, In_TwoO_ThreeUsing a dielectric such as
preferable.

The anti-reflection 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 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 69 mol% of terephthalic acid and 31 mol% of isophthalic acid with respect to the acid component, 31 mol% of ethylene glycol with respect to the alcohol component, and 69 mol% of tricyclodecanedimethanol.

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 resulting mixture was stirred with 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 was obtained in which the absorption was flat in the visible region from a wavelength of 400 nm to 650 nm, and the absorption was sharp at a wavelength of 700 nm or more. The resulting film was allowed to stand in an atmosphere of 60 ° C. and 95% for 500 hours, and the spectral characteristics were measured again. The results were as shown in FIG. 2, and although a slight color change was observed, the near-infrared absorption characteristics were maintained. Also,
When the obtained film was placed on the front surface of a plasma display or the like, there was no change in color tone, the contrast was improved, and near-infrared radiation was reduced.

[0029]

[Table 1]

Example 2 Using the resin (A1) prepared in Example 1 and a composition as shown in Table 2, an infrared absorbing dye, a prepared resin and a solvent were placed in a flask, stirred while heating, and dyed. And the binder resin was dissolved. Further, the dissolved resin is applied to a highly transparent polyester film substrate (Toyobo Cosmoshine A4).
100) 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.
Next, a hard coat treatment layer (HC) was provided on the surface of the transparent polyester film opposite to the produced infrared absorbing layer.
As the hard coating agent, epoxy acrylic resin 100
Using a UV-curable resin composition in which 4 parts of benzophenone was added to each part, a film was formed by a bar coating method, preliminarily dried at 80 ° C. for 5 minutes, and cured by irradiation with UV light at 500 mJ / cm ² . The thickness after curing is 5 μm.

Next, tin oxide of 380 ° is laminated on the infrared absorption layer using a high-frequency magnetron sputtering apparatus, and subsequently, using a DC magnetron sputtering apparatus,
An electromagnetic wave shielding layer was formed by laminating a 200 ° silver thin film and further laminating a 410 ° tin oxide layer. The surface resistance at this time was about 4Ω / □. FIG. 3 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, 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. When 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, a slight color change was observed, but the near infrared absorption characteristics were maintained. In addition, when the obtained film was placed on the front surface of a plasma display or the like, there was no change in color,
The contrast was improved, and near-infrared radiation and electromagnetic radiation were also reduced.

[0032]

[Table 2]

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 multilayer conductive layer of tin oxide and silver was provided in the same manner as in Example 2. 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, when the manufactured infrared absorption filter was installed in front of the plasma display, the entire image had a greenish color tone.

[0035]

[Table 3]

[0036]

The present invention has a wide absorption in the near infrared region, and
An infrared absorption filter that has a high transmittance in the visible region and does not significantly absorb a specific visible light region wavelength can be obtained, and has little color shift even when used in a video camera, a display, or the like. In addition, it has excellent environmental stability and can be used for a long period of time.

[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.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/66 101 H04N 5/66 101Z (72) Inventor Yozo Yamada 2-1-1 Katata 2-chome, Otsu City, Shiga Prefecture No. F-term in Toyobo Co., Ltd. Research Laboratory (reference) 2H048 CA03 CA12 CA19 CA20 CA23 CA27 CA29 2H083 AA04 AA19 AA26 5C022 AC55 5C058 AA11 BA35 5G435 AA03 AA04 BB01 BB06 BB15 CC12 DD12 FF14 GG12 HH02 HH03 H12 H12 H07

Claims (12)

[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%.
An infrared absorption filter comprising an infrared absorption layer having a transmittance at 550 nm of 50% or more and a transparent conductive layer on the same surface as the infrared absorption layer or on the opposite surface. 2. The infrared absorption filter according to claim 1, wherein the infrared absorption layer contains at least any one of a diimonium salt compound, a fluorinated phthalocyanine compound, and a nickel complex as an infrared absorption 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 comprising a polyester resin as a dispersion medium for the dye in the infrared-absorbing layer according to claim 1. 5. An infrared absorption filter, wherein the transparent substrate according to claim 1 is a polyester film. 6. The infrared absorption according to claim 1, wherein a glass transition temperature of a polymer used as a dispersion medium for dispersing the dye is higher than a use guarantee temperature of a device using the filter. filter. 7. An infrared absorption filter according to claim 1, wherein the transparent conductive layer is a metal oxide. 8. An infrared absorption filter according to claim 1, wherein the transparent conductive layer has a repeating structure of three or more layers of metal oxide / metal / metal oxide. 9. An infrared absorbing filter according to claim 8, wherein the metal layer of the transparent conductive layer is silver or gold and a compound containing them. 10. An infrared-absorbing film according to claim 1, further comprising an antireflection layer as an outermost layer. 11. An infrared absorbing film according to any one of claims 1 to 8, further comprising an antiglare layer as an outermost layer. 12. A plasma display filter using the infrared absorption filter according to any one of claims 1 to 10.