JPH11326629A - Infrared absorption filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb unwanted infrared rays for preventing malfunctions of a remote controller using infrared rays by setting the transmittance of an infrared region in a specific wavelength range to a specific value or lower. SOLUTION: The difference between a maximum value and a minimum value of the transmittance in a visible region of wavelengths from 450 to 650 nm is less than 10%, and the transmittance for wavelength 550 nm is higher than or equal to 50%. It is desirable that the transmittance in a near-infrared region of the wavelengths 800 to 1,100 nm be less than or equal to 30%, and the difference between a maximum value and a minimum value of the transmittance in the visible region of wavelengths from 450 to 650 nm be less than a equal to 10% after a filter is left standing for 1,000 hours in the atmosphere of 60 deg.C and 90% humidity. If the difference in transmittance for wavelengths from 450 to 650 nm is within this range, the tone is gray, and the tone emitted from a display is represented without changing at the time of placing this filter in the front of the display. It is desirable that the filter have a constitution such that infrared absorbing coloring matters are dispersed in a polymer and a transparent substrate coated with them.

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
3, JP-A-60-43605, etc.)

[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), many infrared absorbing dyes such as phthalocyanine, nickel complex, azo compound, polymethine, diphenylmethane, triphenylmethane, and quinone are used. However, each of them has problems such as insufficient absorption and 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. .

[0004]

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, the present invention provides a wavelength of 800 nm to 1100 nm.
Wherein 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. Also,
According to the present invention, 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%, and
In the infrared absorption filter whose transmittance at 550nm is 50% or more, the transmittance in the near infrared region from 800nm to 1100nm after leaving in an air atmosphere of 60 ° C and 90% humidity for 1000 hours is 30% or less, Further, it is desirable 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.

If the transmittance at a wavelength of 550 nm is less than 50%, the display at the front of the display becomes very dark, so that the transmittance at the wavelength is 5%.
0% or more is preferable. In the present invention, it is preferable that an infrared absorbing dye is dispersed in a polymer, and this is 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 in the present invention,
It is preferable that the glass transition temperature is a temperature equal to or higher than the assumed guaranteed temperature at which the filter of the present invention is used. This allows
The stability of the dye is improved.

[0006] The infrared absorbing dye used in the present invention is not particularly limited, but the following may be mentioned as an example.

[0007] Kayasorb IRG-022, IRG manufactured by Nippon Kayaku
-023, ExcolorIR1, IR2, IR3, I manufactured by Nippon Shokubai Co., Ltd.
R4, Mitsui Chemicals SIR-128, SIR-130, SIR-132, SIR
-159 and the like, but the 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.

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 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 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 the figure, the absorption is flat in the visible region from 400 nm to 650 nm, and the absorption is 450 to 650 nm.
The difference between the maximum value and the minimum value of the transmittance between nm was 4.8%, and the minimum transmittance was 69.4%. In addition, wavelength 700n
m or more, a film with sharp absorption is obtained, and the wavelength is 800n
The transmission in the m or 1100 nm range was at most 23.4%.

The obtained film is placed in an atmosphere of 60% at 95%.
After leaving for 000 hours, the spectral characteristics were measured again.
And a slight color change can be seen,
The difference between the maximum value and the minimum value of the transmittance between
9.8%, transmittance was at least 65.5%,
The maximum transmittance in the wavelength range of 800 nm or 1100 nm is 29.
Near infrared absorption characteristics were maintained at 1%. Further, when the obtained film was arranged on the front surface of a plasma display or the like, there was no change in color tone, the contrast was improved, and the emission of near-infrared rays was reduced.

[0013]

[Table 1]

Comparative Example 1 An infrared-absorbing dye, a binder resin and a solvent having a composition 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. 3 shows the spectral characteristics. As shown in FIG.
In a visible region up to 550 nm, a peak-shaped characteristic having a peak at about 550 nm is obtained. The difference between the maximum value and the minimum value of the transmittance between wavelengths 450 to 650 nm is 11.5%, and the minimum transmittance is 71. When the wavelength was 700 nm or more, a film having sharp absorption was obtained.
An infrared absorbing film having a maximum transmittance of 44.0% in the range of 00 nm was obtained. 95% of the obtained film at 60 ° C
When left for 1000 hours in an atmosphere and the spectral characteristics were measured again, the difference between the maximum value and the minimum value of the transmittance between wavelengths 450 and 650 nm was 11.5%, and 28.6 was obtained.
% And the transmittance was a minimum of 54%, and the transmittance in the wavelength range from 800 nm to 1100 nm was a maximum of 49.0.
% Has increased. Also, the appearance had changed considerably to green. FIG. 4 shows the spectral characteristics. 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.

[0015]

[Table 2]

Comparative Example 2 An infrared-absorbing dye, a binder resin and a solvent having the composition shown in Table 3 were used in a flask by using Toyobo's 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 color of the obtained infrared absorbing film was dark gray visually. Its spectral characteristics were almost the same as in Example 1. Absorption was flat in the visible region from a wavelength of 400 nm to 650 nm, and absorption was sharp at a wavelength of 700 nm or more. Take the resulting film 60
When left in an atmosphere of 95 ° C. for 95 hours and spectral characteristics were measured again, the result was as shown in FIG.
The difference between the maximum value and the minimum value of the transmittance between m was 4.8%, but increased to 27.4%, and the transmittance was 44.0 at the minimum.
%, And the transmittance in the wavelength range from 800 nm to 1100 nm increased to a maximum of 47.2%. In addition, the appearance has changed to green. Further, when the obtained film was disposed on the front surface of a plasma display or the like, it was colored green.

[0017]

[Table 3]

[0018]

The present invention has a wide absorption in the near infrared region, and
An infrared absorption filter that has high transmittance in the visible region and does not significantly absorb a specific visible region wavelength is obtained, and has little color shift even when used in a video camera, 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 Comparative Example 1.

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

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

Claims (5)

[Claims] 1. The transmittance in the near infrared region of wavelengths from 800 nm to 1100 nm is 30% or less, the difference between the maximum value and the minimum value in the visible region of wavelengths from 450 nm to 650 nm is within 10%, and An infrared absorption filter with a transmittance of 50% or more at a wavelength of 550 nm that is 10% in an air atmosphere at 60 ° C and 95% humidity.
After standing for 00 hours, the transmittance in the near-infrared region from 800 nm to 1100 nm is 30% or less, and the wavelength is from 450 nm to 650 nm.
Wherein the difference between the maximum value and the minimum value of the transmittance in the visible region is within 10%. 2. An infrared-absorbing filter, wherein the infrared-absorbing film according to claim 1 is coated on a transparent substrate with a polymer in which dyes and dyes that absorb infrared rays are dispersed. 3. An infrared absorbing filter, wherein the polymer according to claim 2 is a polyester resin. 4. An infrared absorbing filter, wherein the transparent substrate according to claim 2 is a polyester film. 5. An infrared absorption filter, wherein the glass transition temperature of a polymer used as a dispersion medium for dispersing the dye according to claim 2 is higher than the guaranteed use temperature of an apparatus using said filter.