USRE39858E1 - Infrared absorption filter - Google Patents

Infrared absorption filter Download PDF

Info

Publication number
USRE39858E1
USRE39858E1 US10/897,394 US89739499A USRE39858E US RE39858 E1 USRE39858 E1 US RE39858E1 US 89739499 A US89739499 A US 89739499A US RE39858 E USRE39858 E US RE39858E
Authority
US
United States
Prior art keywords
infrared
filter
layer
infrared absorption
transmittance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US10/897,394
Inventor
Tetsuo Shimomura
Shinya Onomichi
Masanori Kobayashi
Yozo Yamada
Seiichiro Yokoyama
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyobo Co Ltd
Boston Scientific Scimed Inc
Original Assignee
Toyobo Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP13303098A external-priority patent/JPH11326629A/en
Priority claimed from JP13303198A external-priority patent/JPH11326630A/en
Priority claimed from JP10193028A external-priority patent/JP2000028826A/en
Priority claimed from JP10193027A external-priority patent/JP2000028825A/en
Priority claimed from JP10251083A external-priority patent/JP2000081510A/en
Application filed by Toyobo Co Ltd filed Critical Toyobo Co Ltd
Assigned to SCIMED LIFE SYSTEMS, INC. reassignment SCIMED LIFE SYSTEMS, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FAUST, RUDOLF, RICHARD, ROBERT E.
Application granted granted Critical
Publication of USRE39858E1 publication Critical patent/USRE39858E1/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/22—Absorbing filters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/208—Filters for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation

Definitions

  • the present invention relates to an optical filter, and more particularly to an optical filter which has a high transmittance in the visible light region and which is capable of intercepting infrared radiation.
  • the filter of the present invention is especially useful for display purposes.
  • the following filters have been conventionally used as a heat ray-absorbing filter or as a filter for adjusting the visibility of video camera:
  • the filter (1) exhibits sharp absorption in the near-infrared region and can intercept infrared radiation at a very high ratio. However, the filter (1) pronouncedly absorbs part of red color in the visible light region so that the transmitted color looks blue. For display purposes, importance is laid on a color balance. In such case, it is difficult to use the filter (1). Another problem is raised about the processability of the filter (1) because it is made of glass.
  • the optical properties of the filter (2) can be freely designed. Further a filter having properties almost equal to the designed properties can be produced.
  • the filter (2) necessitates a plurality of layers differing in refractive index from each other for this purpose, consequently entailing a drawback of incurring high production costs.
  • the filter (2) should have a uniform thickness of high precision over the entire area, resulting in a difficulty in producing the filter.
  • the filter (3) has improved processability compared with the filter (1).
  • the filter (3) exhibits sharp absorption and absorbs the red color of light beams as is the case with the filter (1), raising the same problem as the filter (1) that the filter (3) looks blue.
  • various infrared-absorbing materials can be used.
  • useful materials are phthalocyanine, nickel complex, azo compound polymethine, diphenylmethane, triphenylmethane, quinone and the like.
  • these materials pose problems of showing insufficient absorption or absorbing a visible light of specific wavelength in the visible light region.
  • the infrared-absorbing materials involve problems of decomposing or oxidizing bringing about absorption in the visible light region or ceasing absorption in the infrared region.
  • An object of the present invention is to provide an infrared absorption filter which can achieve absorption in the near-infrared region, the filter showing a high transmittance in the visible light region, being free from marked absorption of a light of specific wavelength in the visible light region, and being excellent in environmental stability and in processability and productivity.
  • the present invention was completed in view of the foregoing situation.
  • the infrared absorption filters of the present invention which have overcome the abovementioned problems are as described below.
  • the first invention provides an infrared-absorbing filter which has a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm; a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm; and a transmittance of not lower than 50% at a wavelength of 550 nm,
  • said filter after being left to stand in the air atmosphere of a temperature of 60° C., and a humidity of 95% for 1000 hours, having a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm, and a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm.
  • the second invention provides an infrared absorption filter as defined in the first invention, wherein after being left to stand in the air atmosphere of a temperature of 80° C. for 1000 hours, the filter has a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm and has a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm.
  • the third invention provides an infrared absorption filter as defined in the first invention, wherein the filter has an infrared-absorbing layer on a transparent substrate, the layer being composed of a coloring matter, dye or pigment for absorbing infrared radiation and a polymer serving as a dispersing medium.
  • the 4th invention provides an infrared absorption filter as defined in the third invention, wherein the amount of the solvent remaining in the infrared-absorbing layer is 5.0 wt. % or less.
  • the 5th invention provides an infrared absorption filter as defined in the third invention, wherein the transparent substrate has a total light transmittance of not lower than 89%, a haze of not higher than 1.6%, a coefficient of static friction of not higher than 0.6 and a coefficient of dynamic friction of not higher than 0.6.
  • the 6th invention provides an infrared absorption filter as defined in the third invention, wherein the transparent substrate is a polyester film.
  • the 7th invention provides an infrared absorption filter as defined in the third invention, wherein the polymer constituting the infrared-absorbing layer has a glass transition temperature of not lower than 80° C.
  • the 8th invention provides an infrared absorption filter as defined in the 7th invention, wherein the polymer constituting the infrared-absorbing layer is a polyester resin.
  • the 9th invention provides an infrared absorption filter as defined in the third invention, wherein the filter has an electroconductive layer of metal mesh having an aperture ratio of not less than 50% on the same side as the infrared-absorbing layer of the filter or on the opposed side thereof.
  • the 10th invention provides an infrared absorption filter as defined in the third invention, wherein the filter has a transparent electroconductive layer on the same side as the infrared-absorbing layer of the filter or on the opposed side thereof.
  • the 11th invention provides an infrared absorption filter as defined in the 10th invention, wherein the transparent electroconductive layer is formed of a metal oxide.
  • the 12th invention provides an infrared absorption filter as defined in the 10th invention, wherein the transparent electroconductive layer has a repeatedly laminated structure in which at least three layers are laminated in the order of metal oxide/metal/metal oxide.
  • the 13th invention provides an infrared absorption filter as defined in the 12th invention, wherein the constituent metal layer of the transparent electroconductive layer is formed of silver, gold or a compound containing any of them.
  • the 14th invention provides an infrared absorption filter as defined in the first invention, wherein a hard coat-treated layer is formed as an outermost layer of the filter.
  • the 15th invention provides an infrared absorption filter as defined in the first invention, wherein an antireflection layer is formed as an outermost layer of the filter.
  • the 16th invention provides an infrared absorption filter as defined in the first invention, wherein an antiglare-treated layer is formed as an outermost layer of the filter.
  • the 17th invention provides an infrared absorption filter as defined in the first invention, wherein the filter is disposed in front of a plasma display.
  • the infrared absorption filter of the present invention is required to have a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm. Since the infrared absorption filter of the present invention has a low transmittance in this region, the filter used for a plasma display or the like can absorb the unwanted infrared radiation emitted from the display, thereby making it possible to prevent erroneous operation of a remote control using infrared radiation.
  • the infrared absorption filter of the present invention essentially has a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm.
  • the filter is given a gray color, and the color originating from the display can be seen without discoloration.
  • the infrared absorption filter of the present invention essentially has a transmittance of not lower than 50% at a wavelength of 550 nm. If the transmittance is lower than 50% at said wavelength, the display looks very dark when the filter is placed in front of the display.
  • the infrared absorption filter of the invention After being left to stand in the air atmosphere at a temperature of 60° C. and a humidity of 95% for 1000 hours, the infrared absorption filter of the invention essentially has a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm and a difference of 10% or less is found between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm.
  • the infrared absorption filter of the invention preferably has a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm and a difference of 10% or less is recognized between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm.
  • an infrared absorption filter is prepared by dispersing an infrared-absorbing material(s) in a polymer and coating a transparent substrate with the obtained dispersion. This process simplifies the production and enables small-lot production.
  • the amount of residual solvent(s) in a coating layer of the infrared absorption filter is 5.0 wt. % or less
  • the filter being prepared by depositing a composition on a substrate, the composition being prepared by dispersing in a binder resin a near-infrared-absorbing material(s) containing a diimmonium salt compound represented by the formula (1) wherein R 1 -R 8 are the same or different from each other and each represents hydrogen or alkyl having 1 to 12 carbon atoms, and X represents SbF 6 , ClO 4 , PF 6 , NO 3 or halogen.
  • the diimmonium salt compound undergoes chemical change and absorption decreases in the near-infrared region, resulting in insufficient interception of near-infrared radiation. In this case, absorption increases in the visible light region, leading to discoloration of the filter in its entirety to deep yellowish green.
  • the drying conditions of the following equations (2) to (4) should be simultaneously fulfilled.
  • the factors in the equation (2) are expressed in the units described blow below: the wind velocity in m/sec, hot air temperature in °C., drying time in minute minutes and thickness of coating layer in ⁇ m. Wind velocity ⁇ (hot air temperature ⁇ 20) ⁇ drying time/thickness of coating layer>48 (2) Hot air temperature: ⁇ 80° C. (3) Drying time: ⁇ ⁇ 60 minutes
  • Binder resins for use herein are not limited insofar as they can uniformly disperse the near-infrared-absorbing material used in the invention. Suitable examples include, for example, polyester resins, acrylic resins, polyamide resins, polyurethane resins, polyolefin resins, polycarbonate resins and the like. Desirably the binder resin for dispersing the near-infrared-absorbing material(s) has a glass transition temperature which is not less than the assumed guaranteed temperature for use of the filter of the invention. Thereby the stability of the near-infrared-absorbing material is increased.
  • the assumed guaranteed temperature for use of the filter of the invention is preferably 80° C. or higher, more preferably 85° C. or higher.
  • Solvents useful in preparing a coating solution in the coating process can be any solvent insofar as they can uniformly disperse the near-infrared-absorbing material and the binder for use herein.
  • useful solvents are acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetone, propyl acetate, methanol, ethanol, isopropyl alcohol, ethyl cellosolve, benzene, toluene, xylene, tetrahydrofuran, n-hezane, n-heptane, methylene chloride, chloroform, N,N-dimethylformamide, water and the like to which the solvents for use herein are not limited.
  • infrared-absorbing materials useful in the present invention. Examples are as follows.
  • the near infrared-absorbing materials in addition to the diimmonium salt compound of the formula (1), one or both of fluorine-containing phthalocyanine compound and dithiol metal complex compound can preferably be contained in the coating solution.
  • the coating solution preferably contains at least two species of diimmonium salt compound, fluorine-containing phthalocyanine compound and nickel complex compound.
  • Preferred proportions of the near infrared-absorbing materials are 0.5 to 0.01 parts by weight of fluorine-containing phthalocyanine compound if used and 1 to 0 part by weight of nickel complex compound, per part by weight of the diimmonium salt compound.
  • diimmonium salt compound of the formula (1) examples include N,N,N′,N′-tetrakis(p-di-n-butylaminophenyl)-p-benzoquinone-diimmonium.ditetrafluoroantimonate, N,N,N′,N′-tetrakis(p-diethylaminophenyl)-p-benzoquinone-diimmonium.ditetrafluoroantimonate, N,N,N′,N′,-tetrakis(p-di-n-butylaminophenyl)-p-benzoquinone-diimmonium.diperchlorate, N,N,N′,N′-tetrakis(p-diethylaminophenyl)-p-benzoquinone-diimmonium.diperchlorate, N,N,N′,N′-tetrakis(p-diethylaminophenyl)-p-
  • Useful fluorine-containing phthalocyanine compounds include, for example, Excolor IR1, IR2, IR3 and IR4 (products of NIPPON SHOKUBAI Co., Ltd.).
  • Useful dithiol metal complex compounds include, for example, SIR-128, SIR-130, SIR-132 and SIR-159 (products of Mitsui Chemicals, Inc.).
  • the infrared absorption filter of the present invention preferably contains a UV-absorbing agent to enhance the resistance to light. Furthermore, in the present invention, the polymer for dispersing the infrared-absorbing material may be crosslinked with a crosslinking agent to impart weatherability and resistance to solvents to the filter.
  • transparent substrate films for use in the infrared absorption filter of the present invention.
  • Useful transparent substrate films include, for example, stretched films formed of polyester resins, acrylic resins, cellulose resins, polyethylene resins, polypropylene resins, polyolefin resins, polyvinyl chloride resins, polycarbonate, phenolic resins, urethane resins or the like. From the standpoint of dispersion stability, environmental load and the like, polyester films are preferable.
  • the transparent polymer film preferably has a total light transmittance of not lower than 89%, a haze of not higher than 1.6%, a coefficient of static friction of not higher than 0.6 and a coefficient of dynamic friction of not higher than 0.6.
  • the infrared absorption filter of the invention which is often used for display purposes has desirably a high total light transmittance, and desirably a low haze.
  • inert particles capable of imparting an uneven surface to the film are used in a reduced amount to increase the total light transmittance and to reduce the haze, generally the coefficient of friction is increased and the slidability is deteriorated, making it difficult to carry out the winding or like operation. If the total light transmittance, haze and coefficient of friction are within the ranges of the invention, it is possible to bring both the windability and the total light transmittance to the desired ranges.
  • the coating layer In order to give the total light transmittance, haze and coefficient of friction in the above mentioned ranges, it is desirable to form a coating layer of 30 to 300 ⁇ m nm thickness on the substrate polymer film, the coating layer containing inert particles of small average particle size not higher than the wavelength of visible light and not to incorporate inert particles into the substrate polymer film.
  • inert particles examples include calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide and like inorganic particles, crosslinked polymer particles, calcium oxalate and like organic particles.
  • silica particles are the most suitable because they have a refractive index relatively similar to that of polyester resin and facilitates formation of a highly transparent film.
  • the inert particles to be incorporated into the coating layer have an average particle size of preferably 0.01 to 1.0 ⁇ m, more preferably 0.02 to 0.5 ⁇ m, most preferably 0.03 to 0.3 ⁇ m. If the average particle size of inert particles is greater than 1.0 ⁇ m, reduced transparency of the film tends to result, whereas the average particle size of less than 0.01 ⁇ m tends to deteriorate the handleability (slidability, windability, blocking prevention, etc.) of the film.
  • the amount of inert particles to be incorporated into the coating layer is 0.1 to 60 wt. %, preferably 0.5 to 50 wt. %, more preferably 1.0 to 40 wt. %, based on the amount of solid in an adhesive layer.
  • the amount of inert particles in the coating layer exceeds 60 wt. %, it is likely to impair the adhesive property of the film and to deteriorate the transparency of the film, whereas less than 0.1 wt. % is likely to deteriorate the handleability (slidability, windability, blocking prevention, etc.) of the film.
  • the filter of the invention preferably has a transparent electroconductive layer or an electroconductive layer of metal mesh having an aperture ratio of not less than 50% on the same side as the infrared-absorbing layer of the filter or on the opposed side thereof. Thereby detrimental electromagnetic waves emitted from a display can be removed.
  • Metal meshes useful in the present invention include, for example, metal foils of high electroconductivity treated by etching to give a mesh, fabric meshes produced from metallic fibers, meshes produced, e.g. by plating a metal on the surface of polymeric fibers, etc.
  • Metals to be used for the electromagnetic wave-absorbing layer are not Limited and can be any metal insofar as the metal is excellent in the electroconductivity and in stability. However, copper, nickel, tungsten and the like are preferred from the viewpoints of processability and costs.
  • the transparent electroconductive layer to be formed in the present invention can be any electroconductive layer, but is preferably one formed from a metal oxide which enables attaining a higher visible light transmission.
  • the multilayered metal structure provides the layer with the desired electroconductivity while retaining the high visible light transmission.
  • Metal oxides for use in the invention can be any metal oxide insofar as they have the desired electroconductivity and visible light transmission.
  • Useful metal oxides include, for example, tin oxide, indium oxide, indium tin oxide, zinc oxide, titanium oxide, bismuth oxide, etc. to which useful metal oxides are not limited.
  • the metal layers to be employed in the invention are preferably those formed of gold, silver or compounds containing any of them from the viewpoint of electroconductivity.
  • the thickness of silver layer is preferably 50 to 200 ⁇ , more preferably 50 to 100 ⁇ . If the silver layer has a thickness exceeding 200 ⁇ , the light transmission is reduced, whereas less than 50 ⁇ increases the resistance value.
  • the thickness of metal oxide layer is preferably 100 to 1000 ⁇ , more preferably 100 to 500 ⁇ . If the thickness of metal oxide layer is greater than 1000 ⁇ , coloration occurs, resulting in discoloration, whereas less than 100 ⁇ thickness increases the resistance value.
  • the thickness of intermediate metal oxide layer is preferably greater than the other metal oxide layers. This increases the light transmission throughout the multilayered structure.
  • a hard coat-treated layer (HC) may be formed as an outermost layer to prevent marring on the infrared absorption filter of the invention.
  • the hard coat-treated layer (HC) may be desirably a cured layer of crosslinkable resin, such as polyester resin, urethane resin, acrylic resin, melamine resin, epoxy resin, silicone resin, polyimide resin or the like which may be used alone or in admixture.
  • the hard coat-treated layer (HC) has a thickness of preferably 1 to 50 ⁇ m, more preferably 2 to 30 ⁇ m.
  • the hard coat-treated layer (HC) can be formed on the surface of the side opposed to the side of the transparent electroconductive film, by coating said surface with the above-mentioned resin by gravure process, reverse process, dyeing process or the like, followed by application of heat, ultraviolet rays, electron rays or like energy to cure the deposited resin.
  • the infrared absorption filter of the invention may contain an antiglare-treated layer (AG) as an outermost layer to enhance the visibility when used for display purposes.
  • AG antiglare-treated layer
  • the antiglare-treated layer (AG) can be formed by coating the surface to be treated with a curable resin, drying the layer, giving an uneven surface by an embossing roll, and applying heat, ultraviolet rays, electron rays or like energy to cure the deposited resin.
  • curable resins are, for example, polyester resins, urethane resins, acrylic resins, melamine resins, epoxy resins, silicone resins, polyimide resins and the like which may be used alone or in admixture.
  • the infrared absorption filter of the invention may contain an antireflection-treated layer (AR) as an outermost layer to enhance the visible light transmission when used for display purposes.
  • the antireflection-treated layer (AR) may be desirably a single layer or plural layers of a material(s) which is different in refractive index from the plastic film.
  • the single layer structure is preferably composed of a material which is lower in refractive index than the plastic film.
  • the material for the layer adjacent to the plastic film has a higher refractive index than the plastic film and the material for the layer or layers over the said adjacent layer has a lower refractive index than the adjacent layer.
  • Materials for forming the antireflection-treated layer (AR) are not limited and may be either organic or inorganic insofar as they can fulfill said relationship of refractive index.
  • Preferred materials are dielectric materials such as CaF 2 , MgF 2 , NaAlF 4 , SiO 2 , ThF 4 , Nd 2 O 3 , SnO 3 , TiO 2 , CeO 2 , ZnS, In 2 O 3 , etc.
  • the antireflective-treated layer (AR) can be produced by a dry coating process such as vacuum deposition process, sputtering process, CVD process, ion plating process or the like or a wet coating process such as gravure process, reverse process, dyeing process or the like.
  • various pretreatments may be carried out, which include, for example, conventional treatments such as corona discharge treatment, plasma treatment, sputtering treatment, electron beam irradiation treatment, UV irradiation treatment, primer treatment, adhesivity-increasing treatment and the like.
  • the spectral property was measured with a self-recording spectrophotometer (Hitachi U-3500 model) in the wavelength rate of 1500 to 200 nm.
  • the amount of residual solvent(s) was measured using GC-9A (manufactured by Shimadzu Corp.) as follows. About 5 mg of the sample was precisely weighed out and was trapped with heating to 150° C. at an inlet port of a gas chromatography for 5 minutes. Then the total amount (A: ppm) of toluene, tetrahydrofuran (THF) and methyl ethyl ketone (MEK) was measured. Since the peaks of THF and MEK overlap each other, they were compared with the reference peak (toluene) and the combined value was determined as conversion value to toluene.
  • A ppm
  • a base polyester to be used as a dispersing medium was prepared as follows. Charged into an autoclave equipped with a thermometer and a stirrer were:
  • polyester copolymer resin (A1) had an inherent viscosity of 0.4 dl/g and a glass transition temperature of 90° C. NMR analysis gave the following copolymer composition ratio:
  • Acid components Terephthalic acid 71 mol % Isophthalic acid 29 mol % Alcohol components Ethylene glycol 28 mol % Tricyclodecane dimethanol 72 mol %
  • a flask was charged with the infrared-absorbing materials, the above-obtained resin and the solvents shown in Table 1 in the proportions indicated therein. The mixture was heated with stirring to dissolve the infrared-absorbing materials and the binder resin in the solvents.
  • the resin solution was applied to a highly transparent polyester film substrate of 100 ⁇ m thickness having a slidable surface on one side and a smooth surface on the other side (product of Toyo Boseki K.K., “Cosmoshine A 4100; total light transmittance 90.9%, haze 0.7, coefficient of static friction (slidable surface/smooth surface: 0.58/>1), coefficient of dynamic friction (slidable surface/smooth surface: 0.42/>1)) using an applicator with a gap of 100 ⁇ m.
  • the deposited layer was dried at a wind velocity of 0.4 m/s and a temperature of 90° C. in a hot air drier for 1 hour.
  • the resulting coating film had a thickness of 25 ⁇ m.
  • the obtained infrared absorption filter had a color of dark gray when seen.
  • the spectral property qf the filter is shown in FIG. 1 .
  • the absorption was plotted as flat in the visible light region in the wavelength range of 400 to 650 nm.
  • a difference was 4.8% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm, and the transmittance in the wavelength range was 69.4% at lowest.
  • the sharp absorption was observed in the wavelength range of 700 nm or higher.
  • the transmittance was 23.4% at highest in the wavelength range of 800 to 1100 nm.
  • the obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the results shown in FIG. 2 . While a slight color change occurred, a difference of 9.8% was found between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm and the transmittance in the wavelength range was 65.5% at lowest. The transmittance was 29.1% at highest in the wavelength range of 800 to 1100 nm and the filter retained the near-infrared-absorbing property.
  • the obtained filter was left to stand in the atmosphere of a temperature of 80° C. for 1000 hours, and the spectral property was evaluated again with the results shown in FIG. 3 . While a slight color change was brought about, a difference was 5.8% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm and the transmittance in the wavelength range was 67.2% at lowest. The transmittance was 21.0% at highest in the wavelength range of 800 to 1100 nm and the filter retained the near-infrared-absorbing property.
  • the obtained filter When disposed in front of a plasma display or the like, the obtained filter showed no change of color and increased the contrast, resulting in reduced level of near-infrared radiation.
  • Vylon RV 200 manufactured by Toyo Boseki K.K. (specific weight 1.26, glass transition temp. 67° C.) was used as a base polymer.
  • a flask was charged with the infrared-absorbing materials, the binder resin and the solvents as shown in Table 2 in the proportions indicated therein. These ingredients were heated with stirring to dissolve the the infrared-absorbing materials and the binder resin in the solvents.
  • the resin solution was applied to a highly transparent polyester film substrate of 100 ⁇ m thickness (product of Toyo Boseki K.K, “Cosmoshine A 4100”) using an applicator with a gap of 100 ⁇ m.
  • the deposited layer was dried at a wind velocity of 0.4 m/s and a temperature of 90° C.
  • the obtained infrared absorption filter had a brown color when seen.
  • the absorption was plotted in a mountain-shaped form having a peak at about 550 nm in the visible light region in the wavelength range of 400 to 650 nm.
  • a difference was 11.5% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm, and the transmittance in the wavelength range was 71.4% at lowest.
  • the sharp absorption was observed in the wavelength range of 700 nm or higher.
  • the transmittance was 44.0% at highest in the wavelength range of 800 to 1100 nm.
  • the filter looked green when seen. When disposed in front of a plasma display or the like, the obtained filter lost a color balance, and turned greenish.
  • the obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the following results.
  • a difference was increased from 11.5% to 28.6% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm and the transmittance in the wavelength range was 54% at lowest.
  • the transmittance was increased to 49.0% at highest in the wavelength range of 800 to 1100 nm.
  • the filter was deep green when seen.
  • the spectral property is shown in FIG. 5 . When disposed in front of a plasma display or the like, the obtained filter lost a color balance, and turned greenish.
  • the obtained filter was left to stand in the atmosphere of a temperature of 80° C. for 1000 hours, and the spectral property was evaluated again with the following results.
  • a difference rose from 11.5% to 20.3% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm and the transmittance in the wavelength range was 61.8% at lowest.
  • the transmittance was increased to 47.2% at highest in the wavelength range of 800 to 1100 nm.
  • the filter was deep green when seen.
  • the spectral property of the filter is shown in FIG. 6 . When disposed in front of a plasma display or the like, the obtained filter lost a color balance, and turned greenish.
  • Vylon RV 200 product of Toyo Boseki K.K., specific weight 1.26, glass transition temp. 67° C.
  • a flask was charged with the infrared-absorbing materials, the binder resin and the solvents as shown in Table 3 in the proportions indicated therein. These ingredients were heated with stirring to dissolve the infrared-absorbing materials and the binder resin in the solvents.
  • the resin solution was applied to a highly transparent polyester film substrate of 100 ⁇ m thickness (product of Toyo Boseki K.K., “Cosmoshine A 4100”) using an applicator with a gap of 100 ⁇ m.
  • the deposited layer was dried at a wind velocity of 0.4 m/s and a temperature of 90° C. in a hot air drier for 1 hour.
  • the resulting coating film had a thickness of 25 ⁇ m.
  • the obtained infrared absorption filter was dark gray when seen.
  • the spectral property of the filter was substantially the same as in Example 1.
  • the absorption was plotted as flat in the visible light region in the wavelength range of 400 to 650 nm.
  • the sharp absorption was observed at 700 nm or more.
  • the obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the results shown in FIG. 7.
  • a difference was increased from 4.8% to 27.4% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm, and the transmittance in the wavelength range was 44.0% at lowest.
  • the transmittance was increased to 47.2% at highest in the wavelength range of 800 to 1100 nm.
  • the filter looked green when seen. When disposed in front of a plasma display or the like, the obtained filter lost a color balance, and turned greenish.
  • the obtained filter was left to stand in the atmosphere of a temperature of 80° C. for 1000 hours, and the spectral property was evaluated again with the results shown in FIG. 8.
  • a difference was increased from 4.8% to 16.6% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm and the transmittance in the wavelength range was 56.3% at lowest.
  • the transmittance was increased to 30.2% at highest in the wavelength range of 800 to 1000 nm.
  • the filter looked green when seen. When disposed in front of a plasma display or the like, the obtained filter looked green.
  • a coating solution was prepared using the polyester copolymer resin (A1) described in Example 1 together with the other ingredients shown in Table 1 in the proportions indicated therein.
  • the coating solution thus obtained was applied to a highly transparent polyester film substrate of 100 ⁇ m thickness (product of Toyo Boseki K.K., “Cosmoshine A 4300”, total transmittance 90.9% haze 0.7, coefficient of static friction (both surfaces) 0.58, coefficient of dynamic friction (both surfaces) 0.42) by a gravure roll.
  • the deposited layer was dried for 1 minute by feeding hot air at a wind velocity of 5 m/s and a temperature of 130° C. and then the filter was wound into a roll.
  • the resulting coating layer had a thickness of 8.0 pm.
  • the amount of residual solvents in the coating layer was 4.1 wt. %.
  • the filter had a high slidability and showed a good roll appearance.
  • the obtained infrared absorption filter looked dark gray when seen.
  • the spectral property of the filter is shown in FIG. 9 .
  • the absorption was plotted as flat in the visible light region in the wavelength range of 400 to 650 nm.
  • the sharp absorption was observed at a wavelength of 700 nm or more.
  • the obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the results shown in FIG. 10 .
  • the filter showed no great change in the spectral curve and exhibited stable performance.
  • Example 1 The coating solution used in Example 1 was applied to a highly transparent polyester film substrate (product to Toyo Boseki K.K., “Cosmoshine A 4300”) by a gravure roll.
  • the deposited layer was dried for 1 minute by feeding hot air at a wind velocity of 5 m/s and a temperature of 120° C.
  • the coating layer had a thickness of 11 ⁇ m.
  • the amount of residual solvents in the coating layer was 6.5 wt. %.
  • the filter looked dark gray when seen.
  • the spectral property of the filter is shown in FIG. 11 . As shown in FIG. 11 , the absorption was plotted as flat in the visible light region in the wavelength range of 450 to 650 nm. The sharp absorption was observed at a wavelength of 700 nm or more.
  • the obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the results shown in FIG. 12 .
  • the absorption in the near-infrared region lowered and the color of the filter turned yellowish green.
  • a hard coat-treated layer (HC) was formed on the surface of the side opposed to the infrared-absorbing layer.
  • a hard coat material used as a hard coat material was a UV-curable resin composition comprising 100 parts of an epoxy acrylic resin and 4 parts of benzophenone.
  • the hard coat-treated layer was formed by a bar coat method. Then, preliminary drying was conducted at 80° C. for 5 minutes and the layer was cured by UV radiation with 500 mJ/cm 2 .
  • the cured hard coat-treated layer (HC) had a thickness of 5 ⁇ m.
  • Copper foil of 9 ⁇ m thickness was bonded to the surface of infrared-absorbing layer with a UV-curing adhesive, the bonded copper foil was patterned with photoresist and etched to give a an electromagnetic wave shielding layer.
  • the copper foil had lines of 15 ⁇ m width, a pitch of 115 ⁇ m and an aperture ratio of 75%
  • FIG. 13 shows the spectral property of the filter having, as described above, the hard coat-treated layer on one side of the transparent polyester film substrate, and the infrared-absorbing layer and the electromagnetic wave shielding layer superposed in this order on the other side thereof.
  • the filter can absorb near-infrared rays, has a gray color and exhibits a high visible light transmission while absorbing an electromagnetic wave.
  • the obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the following results. Although a little changed in color, the filter maintained the near-infrared absorbing property. When disposed in front of a plasma display or the like, the obtained filter did not undergo change of color and increased the contrast, resulting in the decrease in radiation of near-infrared beams and in radiation of electromagnetic wave.
  • a hard coat-treated layer (HC) was formed on the surface of the side opposed to the infrared-absorbing layer.
  • a hard coat material used as a hard coat material was a UV-curing resin composition comprising 100 parts of an epoxy acrylic resin and 4 parts of benzophenone.
  • the hard coat-treated layer was formed by a bar coat method. Then, preliminary drying was conducted at 80° C. for 5 minutes and the layer was cured by UV radiation with 500 mJ/cm 2 .
  • the cured hard coat-treated layer (HC) had a thickness of 5 ⁇ m.
  • FIG. 14 shows the spectral property of the filter having, as described above, the hard coat-treated layer on one side of the transparent polyester film substrate, and the infrared-absorbing layer and the electromagnetic wave shielding layer laminated in this order on the other side thereof.
  • the filter can absorb near-infrared rays, has a gray color, and exhibits a high visible light transmission while absorbing the electromagnetic wave.
  • the obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the following results. Although a little changed in color, the filter maintained the near-infrared absorbing property. When disposed in front of a plasma display or the like, the obtained filter did not undergo change of color and increased the contrast, resulting in the decrease in radiation of near-infrared beams and in radiation of electromagnetic wave.
  • FIG. 1 shows the spectral property of the infrared absorption filter prepared in Example 1.
  • FIG. 2 shows the spectral property of the infrared absorption filter prepared in Example 1 after the filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours.
  • FIG. 3 shows the spectral property of the infrared absorption filter prepared in Example 1 after the filter was left to stand in the atmosphere of a temperature of 80° C. for 1000 hours.
  • FIG. 4 shows the spectral property of the infrared absorption filter prepared in Comparative Example 1.
  • FIG. 5 shows the spectral property of the infrared absorption filter prepared in Comparative Example 1 after the filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours.
  • FIG. 6 shows the spectral property of the infrared absorption filter prepared in Comparative Example 1 after the filter was left to stand in the atmosphere of a temperature of 80° C. for 1000 hours.
  • FIG. 7 shows the spectral property of the infrared absorption filter prepared in Comparative Example 2 after the filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours.
  • FIG. 8 shows the spectral property of thy infrared absorption filter prepared in Comparative Example 2 after the filter was left to stand in the atmosphere of a temperature of 80° C. for 1000 hours.
  • FIG. 9 shows the spectral property of the infrared absorption filter prepared in Example 2.
  • FIG. 10 shows the spectral property of the infrared absorption filter prepared in Example 2 after the filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours.
  • FIG. 11 shows the spectral property of the infrared absorption filter prepared in Comparative Example 3.
  • FIG. 12 shows the spectral property of the infrared absorption filter prepared in Comparative Example 3 after the filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours.
  • FIG. 13 shows the spectral property of the infrared absorption filter prepared in Example 3.
  • FIG. 14 shows the spectral property of the infrared absorption filter prepared in Example 4.
  • the infrared absorption filter of the present invention has broad absorption in the near-infrared region, shows a high visible light transmission and does not markedly absorb a specific light in the visible light wavelengths.
  • the filter can absorb the unwanted infrared radiation emitted from the display, thereby making it possible to prevent erroneous operational of a remote control using infrared radiation.
  • the infrared absorption filter of the present invention is gray in color so that it is unlikely to cause color change when used for a video camera, display or the like. Further the filter of the invention has such a high environmental stability that the filter can maintain said properties in an environment of a high temperature and a high humidity.

Abstract

The infrared absorption filter of the present invention has a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm; a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm; and a transmittance of not lower than 50% at a wavelength of 550 nm, the filter being so excellent in environmental stability that after being left to stand in the air atmosphere at a temperature of 60° C. and a humidity of 95% for 1000 hours, the filter can maintain said spectral property in said range. Consequently, when used for a plasma display or the like, the filter can absorb the unwanted infrared rays radiated from the display, resulting in preventing erroneous operation of a remote control using infrared radiation even in such a high-temperature and high-humidity environment. The filter is gray in color so that when placed in front of a display, the color originated in the display can be seen without discoloration.

Description

CROSS REFERENCE TO RELATED APPLICATION
More than one reissue application has been filed for the reissue of U.S. Pat. No. 6,522,463. The reissue applications are application Ser. No. 10/897,394 (the present application), and its continuation, application Ser. No. 10/897,393.
FIELD OF THE INVENTION
The present invention relates to an optical filter, and more particularly to an optical filter which has a high transmittance in the visible light region and which is capable of intercepting infrared radiation. The filter of the present invention is especially useful for display purposes.
BACKGROUND ART
The following filters have been conventionally used as a heat ray-absorbing filter or as a filter for adjusting the visibility of video camera:
    • (1) a filter composed of phosphate glass containing metallic ions such as copper or iron ions (Japanese Unexamined Patent Publication No.235740/1985, Japanese Unexamined Patent Publication No.153144/1987, etc.);
    • (2) an interference filter having plural layers differing from each other in refractive index on a substance to allow light of specific wavelength to pass by interference of transmitted light (Japanese Unexamined Patent Publication No.21091/1980, Japanese Unexamined Patent Publication No.184745/1984, etc.);
    • (3) an acrylic resin filter composed of a copolymer containing copper ions (Japanese Unexamined Patent Publication No.324213/1994); and
    • (4) a filter composed of a binder resin and a coloring matter dispersed in the binder resin (Japanese Unexamined Patent Publication No.21458/1982, Japanese Unexamined Patent Publication No.198413/1982, Japanese Unexamined Patent Publication No.43605/1985, etc.).
The above-mentioned conventional infrared absorption filters have problems as described below.
The filter (1) exhibits sharp absorption in the near-infrared region and can intercept infrared radiation at a very high ratio. However, the filter (1) pronouncedly absorbs part of red color in the visible light region so that the transmitted color looks blue. For display purposes, importance is laid on a color balance. In such case, it is difficult to use the filter (1). Another problem is raised about the processability of the filter (1) because it is made of glass.
The optical properties of the filter (2) can be freely designed. Further a filter having properties almost equal to the designed properties can be produced. However, the filter (2) necessitates a plurality of layers differing in refractive index from each other for this purpose, consequently entailing a drawback of incurring high production costs. Moreover, when a large area is required, the filter (2) should have a uniform thickness of high precision over the entire area, resulting in a difficulty in producing the filter.
The filter (3) has improved processability compared with the filter (1). However, the filter (3) exhibits sharp absorption and absorbs the red color of light beams as is the case with the filter (1), raising the same problem as the filter (1) that the filter (3) looks blue.
In the filter (4), various infrared-absorbing materials can be used. Examples of useful materials are phthalocyanine, nickel complex, azo compound polymethine, diphenylmethane, triphenylmethane, quinone and the like. However, when singly used, these materials pose problems of showing insufficient absorption or absorbing a visible light of specific wavelength in the visible light region. Further, when the filter is left to stand at a high temperature or a high humidity for a long time, the infrared-absorbing materials involve problems of decomposing or oxidizing bringing about absorption in the visible light region or ceasing absorption in the infrared region.
An object of the present invention is to provide an infrared absorption filter which can achieve absorption in the near-infrared region, the filter showing a high transmittance in the visible light region, being free from marked absorption of a light of specific wavelength in the visible light region, and being excellent in environmental stability and in processability and productivity.
DISCLOSURE OF THE INVENTION
The present invention was completed in view of the foregoing situation. The infrared absorption filters of the present invention which have overcome the abovementioned problems are as described below.
The first invention provides an infrared-absorbing filter which has a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm; a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm; and a transmittance of not lower than 50% at a wavelength of 550 nm,
said filter, after being left to stand in the air atmosphere of a temperature of 60° C., and a humidity of 95% for 1000 hours, having a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm, and a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm.
The second invention provides an infrared absorption filter as defined in the first invention, wherein after being left to stand in the air atmosphere of a temperature of 80° C. for 1000 hours, the filter has a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm and has a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm.
The third invention provides an infrared absorption filter as defined in the first invention, wherein the filter has an infrared-absorbing layer on a transparent substrate, the layer being composed of a coloring matter, dye or pigment for absorbing infrared radiation and a polymer serving as a dispersing medium.
The 4th invention provides an infrared absorption filter as defined in the third invention, wherein the amount of the solvent remaining in the infrared-absorbing layer is 5.0 wt. % or less.
The 5th invention provides an infrared absorption filter as defined in the third invention, wherein the transparent substrate has a total light transmittance of not lower than 89%, a haze of not higher than 1.6%, a coefficient of static friction of not higher than 0.6 and a coefficient of dynamic friction of not higher than 0.6.
The 6th invention provides an infrared absorption filter as defined in the third invention, wherein the transparent substrate is a polyester film.
The 7th invention provides an infrared absorption filter as defined in the third invention, wherein the polymer constituting the infrared-absorbing layer has a glass transition temperature of not lower than 80° C.
The 8th invention provides an infrared absorption filter as defined in the 7th invention, wherein the polymer constituting the infrared-absorbing layer is a polyester resin.
The 9th invention provides an infrared absorption filter as defined in the third invention, wherein the filter has an electroconductive layer of metal mesh having an aperture ratio of not less than 50% on the same side as the infrared-absorbing layer of the filter or on the opposed side thereof.
The 10th invention provides an infrared absorption filter as defined in the third invention, wherein the filter has a transparent electroconductive layer on the same side as the infrared-absorbing layer of the filter or on the opposed side thereof.
The 11th invention provides an infrared absorption filter as defined in the 10th invention, wherein the transparent electroconductive layer is formed of a metal oxide.
The 12th invention provides an infrared absorption filter as defined in the 10th invention, wherein the transparent electroconductive layer has a repeatedly laminated structure in which at least three layers are laminated in the order of metal oxide/metal/metal oxide.
The 13th invention provides an infrared absorption filter as defined in the 12th invention, wherein the constituent metal layer of the transparent electroconductive layer is formed of silver, gold or a compound containing any of them.
The 14th invention provides an infrared absorption filter as defined in the first invention, wherein a hard coat-treated layer is formed as an outermost layer of the filter.
The 15th invention provides an infrared absorption filter as defined in the first invention, wherein an antireflection layer is formed as an outermost layer of the filter.
The 16th invention provides an infrared absorption filter as defined in the first invention, wherein an antiglare-treated layer is formed as an outermost layer of the filter.
The 17th invention provides an infrared absorption filter as defined in the first invention, wherein the filter is disposed in front of a plasma display.
The infrared absorption filter of the present invention is required to have a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm. Since the infrared absorption filter of the present invention has a low transmittance in this region, the filter used for a plasma display or the like can absorb the unwanted infrared radiation emitted from the display, thereby making it possible to prevent erroneous operation of a remote control using infrared radiation.
The infrared absorption filter of the present invention essentially has a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm. When the infrared absorption filter of the present invention has the difference in this range of transmittance within the wavelength range of 450 to 650 nm, the filter is given a gray color, and the color originating from the display can be seen without discoloration.
Further, the infrared absorption filter of the present invention essentially has a transmittance of not lower than 50% at a wavelength of 550 nm. If the transmittance is lower than 50% at said wavelength, the display looks very dark when the filter is placed in front of the display.
After being left to stand in the air atmosphere at a temperature of 60° C. and a humidity of 95% for 1000 hours, the infrared absorption filter of the invention essentially has a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm and a difference of 10% or less is found between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm.
After being left to stand in the air atmosphere at a temperature of 80° C. for 1000 hours, the infrared absorption filter of the invention preferably has a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm and a difference of 10% or less is recognized between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm.
Embodiments of the present invention are described below in detail.
According to a preferred embodiment of the invention, an infrared absorption filter is prepared by dispersing an infrared-absorbing material(s) in a polymer and coating a transparent substrate with the obtained dispersion. This process simplifies the production and enables small-lot production.
Preferably the amount of residual solvent(s) in a coating layer of the infrared absorption filter is 5.0 wt. % or less, the filter being prepared by depositing a composition on a substrate, the composition being prepared by dispersing in a binder resin a near-infrared-absorbing material(s) containing a diimmonium salt compound represented by the formula (1)
Figure USRE039858-20070925-C00001
wherein R1-R8 are the same or different from each other and each represents hydrogen or alkyl having 1 to 12 carbon atoms, and X represents SbF6, ClO4, PF6, NO3 or halogen.
If the filter containing more than 5.0 wt. % of the solvent in the coating layer is left to stand at a high temperature and a high humidity for a long time, the diimmonium salt compound undergoes chemical change and absorption decreases in the near-infrared region, resulting in insufficient interception of near-infrared radiation. In this case, absorption increases in the visible light region, leading to discoloration of the filter in its entirety to deep yellowish green.
To bring the amount of residual solvent(s) to 5.0 wt. % or less, the drying conditions of the following equations (2) to (4) should be simultaneously fulfilled. The factors in the equation (2) are expressed in the units described blow below: the wind velocity in m/sec, hot air temperature in °C., drying time in minute minutes and thickness of coating layer in μm.
Wind velocity×(hot air temperature−20)×drying time/thickness of coating layer>48   (2)
Hot air temperature: ≧80° C.   (3)
Drying time: ≧ ≦60 minutes
Binder resins for use herein are not limited insofar as they can uniformly disperse the near-infrared-absorbing material used in the invention. Suitable examples include, for example, polyester resins, acrylic resins, polyamide resins, polyurethane resins, polyolefin resins, polycarbonate resins and the like. Desirably the binder resin for dispersing the near-infrared-absorbing material(s) has a glass transition temperature which is not less than the assumed guaranteed temperature for use of the filter of the invention. Thereby the stability of the near-infrared-absorbing material is increased. The assumed guaranteed temperature for use of the filter of the invention is preferably 80° C. or higher, more preferably 85° C. or higher.
Solvents useful in preparing a coating solution in the coating process can be any solvent insofar as they can uniformly disperse the near-infrared-absorbing material and the binder for use herein. Examples of useful solvents are acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetone, propyl acetate, methanol, ethanol, isopropyl alcohol, ethyl cellosolve, benzene, toluene, xylene, tetrahydrofuran, n-hezane, n-heptane, methylene chloride, chloroform, N,N-dimethylformamide, water and the like to which the solvents for use herein are not limited.
There is no limitation on infrared-absorbing materials useful in the present invention. Examples are as follows.
As the near infrared-absorbing materials, in addition to the diimmonium salt compound of the formula (1), one or both of fluorine-containing phthalocyanine compound and dithiol metal complex compound can preferably be contained in the coating solution. The coating solution preferably contains at least two species of diimmonium salt compound, fluorine-containing phthalocyanine compound and nickel complex compound. Preferred proportions of the near infrared-absorbing materials are 0.5 to 0.01 parts by weight of fluorine-containing phthalocyanine compound if used and 1 to 0 part by weight of nickel complex compound, per part by weight of the diimmonium salt compound.
Examples of the diimmonium salt compound of the formula (1) are N,N,N′,N′-tetrakis(p-di-n-butylaminophenyl)-p-benzoquinone-diimmonium.ditetrafluoroantimonate, N,N,N′,N′-tetrakis(p-diethylaminophenyl)-p-benzoquinone-diimmonium.ditetrafluoroantimonate, N,N,N′,N′,-tetrakis(p-di-n-butylaminophenyl)-p-benzoquinone-diimmonium.diperchlorate, N,N,N′,N′-tetrakis(p-diethylaminophenyl)-p-benzoquinone-diimmonium.diperchlorate, N,N,N′,N′-tetrakis(p-diisopropylaminophenyl)-p-benzoquinone-diimmonium.ditetrafluorophosphate, N,N,N′,N′-tetrakis(p-n-propylaminophenyl)-p-benzoquinone-diimmonium.dinitrate and so on to which, however, useful diimmonium salt compounds are not limited. Some of them are commercially available. Among them, Kayasorb IRG-022, IRG-023 and the like (products of NIPPON KAYAKU Co., Ltd.) are suitably usable.
Useful fluorine-containing phthalocyanine compounds include, for example, Excolor IR1, IR2, IR3 and IR4 (products of NIPPON SHOKUBAI Co., Ltd.). Useful dithiol metal complex compounds include, for example, SIR-128, SIR-130, SIR-132 and SIR-159 (products of Mitsui Chemicals, Inc.).
The infrared absorption filter of the present invention preferably contains a UV-absorbing agent to enhance the resistance to light. Furthermore, in the present invention, the polymer for dispersing the infrared-absorbing material may be crosslinked with a crosslinking agent to impart weatherability and resistance to solvents to the filter.
There is no limitation on transparent substrate films for use in the infrared absorption filter of the present invention. Useful transparent substrate films include, for example, stretched films formed of polyester resins, acrylic resins, cellulose resins, polyethylene resins, polypropylene resins, polyolefin resins, polyvinyl chloride resins, polycarbonate, phenolic resins, urethane resins or the like. From the standpoint of dispersion stability, environmental load and the like, polyester films are preferable.
In the infrared absorption filter having the infrared-absorbing layer on at least one side of the transparent polymer film, the transparent polymer film preferably has a total light transmittance of not lower than 89%, a haze of not higher than 1.6%, a coefficient of static friction of not higher than 0.6 and a coefficient of dynamic friction of not higher than 0.6.
The infrared absorption filter of the invention which is often used for display purposes has desirably a high total light transmittance, and desirably a low haze. However, if inert particles capable of imparting an uneven surface to the film are used in a reduced amount to increase the total light transmittance and to reduce the haze, generally the coefficient of friction is increased and the slidability is deteriorated, making it difficult to carry out the winding or like operation. If the total light transmittance, haze and coefficient of friction are within the ranges of the invention, it is possible to bring both the windability and the total light transmittance to the desired ranges.
In order to give the total light transmittance, haze and coefficient of friction in the above mentioned ranges, it is desirable to form a coating layer of 30 to 300 μm nm thickness on the substrate polymer film, the coating layer containing inert particles of small average particle size not higher than the wavelength of visible light and not to incorporate inert particles into the substrate polymer film.
Examples of such inert particles are calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide and like inorganic particles, crosslinked polymer particles, calcium oxalate and like organic particles. Among them, silica particles are the most suitable because they have a refractive index relatively similar to that of polyester resin and facilitates formation of a highly transparent film.
The inert particles to be incorporated into the coating layer have an average particle size of preferably 0.01 to 1.0 μm, more preferably 0.02 to 0.5 μm, most preferably 0.03 to 0.3 μm. If the average particle size of inert particles is greater than 1.0 μm, reduced transparency of the film tends to result, whereas the average particle size of less than 0.01 μm tends to deteriorate the handleability (slidability, windability, blocking prevention, etc.) of the film. The amount of inert particles to be incorporated into the coating layer is 0.1 to 60 wt. %, preferably 0.5 to 50 wt. %, more preferably 1.0 to 40 wt. %, based on the amount of solid in an adhesive layer. If the amount of inert particles in the coating layer exceeds 60 wt. %, it is likely to impair the adhesive property of the film and to deteriorate the transparency of the film, whereas less than 0.1 wt. % is likely to deteriorate the handleability (slidability, windability, blocking prevention, etc.) of the film.
The filter of the invention preferably has a transparent electroconductive layer or an electroconductive layer of metal mesh having an aperture ratio of not less than 50% on the same side as the infrared-absorbing layer of the filter or on the opposed side thereof. Thereby detrimental electromagnetic waves emitted from a display can be removed.
Metal meshes useful in the present invention include, for example, metal foils of high electroconductivity treated by etching to give a mesh, fabric meshes produced from metallic fibers, meshes produced, e.g. by plating a metal on the surface of polymeric fibers, etc. Metals to be used for the electromagnetic wave-absorbing layer are not Limited and can be any metal insofar as the metal is excellent in the electroconductivity and in stability. However, copper, nickel, tungsten and the like are preferred from the viewpoints of processability and costs.
The transparent electroconductive layer to be formed in the present invention can be any electroconductive layer, but is preferably one formed from a metal oxide which enables attaining a higher visible light transmission. To increase the electroconductivity of the transparent electroconductive layer, it is preferred to provide a repeatedly laminated structure in which at least three layers are laminated in the order of metal oxide/metal/metal oxide. The multilayered metal structure provides the layer with the desired electroconductivity while retaining the high visible light transmission.
Metal oxides for use in the invention can be any metal oxide insofar as they have the desired electroconductivity and visible light transmission. Useful metal oxides include, for example, tin oxide, indium oxide, indium tin oxide, zinc oxide, titanium oxide, bismuth oxide, etc. to which useful metal oxides are not limited. The metal layers to be employed in the invention are preferably those formed of gold, silver or compounds containing any of them from the viewpoint of electroconductivity.
When the electroconductive layer has a multi-layered structure, e.g. a three-layer structure comprising layers each formed of metal oxide, metal and metal oxide, respectively in this order, the thickness of silver layer is preferably 50 to 200 Å, more preferably 50 to 100 Å. If the silver layer has a thickness exceeding 200 Å, the light transmission is reduced, whereas less than 50 Å increases the resistance value. The thickness of metal oxide layer is preferably 100 to 1000 Å, more preferably 100 to 500 Å. If the thickness of metal oxide layer is greater than 1000 Å, coloration occurs, resulting in discoloration, whereas less than 100 Å thickness increases the resistance value. When a structure of more than three layers is provided, e.g. a 5-layer structure composed of metal oxide, silver, metal oxide, silver and metal oxide in this order, the thickness of intermediate metal oxide layer is preferably greater than the other metal oxide layers. This increases the light transmission throughout the multilayered structure.
A hard coat-treated layer (HC) may be formed as an outermost layer to prevent marring on the infrared absorption filter of the invention. The hard coat-treated layer (HC) may be desirably a cured layer of crosslinkable resin, such as polyester resin, urethane resin, acrylic resin, melamine resin, epoxy resin, silicone resin, polyimide resin or the like which may be used alone or in admixture.
The hard coat-treated layer (HC) has a thickness of preferably 1 to 50 μm, more preferably 2 to 30 μm. The thickness of less than 1 μm, the hard coat-treated layer fails to sufficiently achieve the intended function, whereas the thickness of more than 50 μm retards the resin-coating operation, making it difficult to obtain a good result concerning the productivity.
The hard coat-treated layer (HC) can be formed on the surface of the side opposed to the side of the transparent electroconductive film, by coating said surface with the above-mentioned resin by gravure process, reverse process, dyeing process or the like, followed by application of heat, ultraviolet rays, electron rays or like energy to cure the deposited resin.
The infrared absorption filter of the invention may contain an antiglare-treated layer (AG) as an outermost layer to enhance the visibility when used for display purposes.
The antiglare-treated layer (AG) can be formed by coating the surface to be treated with a curable resin, drying the layer, giving an uneven surface by an embossing roll, and applying heat, ultraviolet rays, electron rays or like energy to cure the deposited resin. Useful curable resins are, for example, polyester resins, urethane resins, acrylic resins, melamine resins, epoxy resins, silicone resins, polyimide resins and the like which may be used alone or in admixture.
The infrared absorption filter of the invention may contain an antireflection-treated layer (AR) as an outermost layer to enhance the visible light transmission when used for display purposes. The antireflection-treated layer (AR) may be desirably a single layer or plural layers of a material(s) which is different in refractive index from the plastic film. The single layer structure is preferably composed of a material which is lower in refractive index than the plastic film. To form a multilayered structure, recommendably the material for the layer adjacent to the plastic film has a higher refractive index than the plastic film and the material for the layer or layers over the said adjacent layer has a lower refractive index than the adjacent layer. Materials for forming the antireflection-treated layer (AR) are not limited and may be either organic or inorganic insofar as they can fulfill said relationship of refractive index. Preferred materials are dielectric materials such as CaF2, MgF2, NaAlF4, SiO2, ThF4, Nd2O3, SnO3, TiO2, CeO2, ZnS, In2O3, etc.
The antireflective-treated layer (AR) can be produced by a dry coating process such as vacuum deposition process, sputtering process, CVD process, ion plating process or the like or a wet coating process such as gravure process, reverse process, dyeing process or the like.
Prior to formation of the hard coat-treated layer (HC), antiglare-treated layer (AG) or antireflection-treated layer (AR), various pretreatments may be carried out, which include, for example, conventional treatments such as corona discharge treatment, plasma treatment, sputtering treatment, electron beam irradiation treatment, UV irradiation treatment, primer treatment, adhesivity-increasing treatment and the like.
Examples of Embodiments
The present invention will be described in more detail with reference to the following Examples to which, however, the invention is not limited. Given below are methods of measuring the property values used herein and methods of evaluating the effect.
(1) Spectral Property
The spectral property was measured with a self-recording spectrophotometer (Hitachi U-3500 model) in the wavelength rate of 1500 to 200 nm.
(2) Environmental Stability
1) Moisture Resistance
After the sample was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, the above-mentioned spectral property was measured.
2) Heat Resistance
After the sample was left to stand in the air atmosphere at 80° C. for 1000 hours, the above-mentioned spectral property was measured.
(3) Amount of Solvent(s) Remaining in the Coating Layer
The amount of residual solvent(s) was measured using GC-9A (manufactured by Shimadzu Corp.) as follows. About 5 mg of the sample was precisely weighed out and was trapped with heating to 150° C. at an inlet port of a gas chromatography for 5 minutes. Then the total amount (A: ppm) of toluene, tetrahydrofuran (THF) and methyl ethyl ketone (MEK) was measured. Since the peaks of THF and MEK overlap each other, they were compared with the reference peak (toluene) and the combined value was determined as conversion value to toluene. Aside from the above, a piece of 10 cm square was cut off from the sample and was weighed out (B: g) and the coating layer was wiped with the solvents. The difference (C: g) between the weights of the sample before and after wiping was determined. The amount of residual solvents was calculated by the following equation.
The amount of residual solvents (%)=A×B×10−4/C
(4) Total Light Transmittance and Haze
Measured with a haze meter (product of Tokyo Denshoku Kogyo K.K., Model TC-H3DP) according to JIS K 7105
(5) Coefficient of Friction
The coefficient of static friction (μs) and the coefficient of dynamic friction (μd) were obtained according to JIS K 7125.
EXAMPLE 1
A base polyester to be used as a dispersing medium was prepared as follows. Charged into an autoclave equipped with a thermometer and a stirrer were:
Dimethyl terephthalate 136 wt. Parts
Dimethyl isophthalate 58 wt. Parts
Ethylene glycol 96 wt. parts
Tricyclodecane dimethanol 137 wt. parts
Antimony trioxide 0.09 wt. part
These ingredients were heated to 170 to 220° C. for 180 minutes to undergo an ester exchange reaction. Then the temperature of the reaction system was elevated to 245° C. to continue the reaction under a pressure of 1 to 10 mmHg for 180 minutes, giving a polyester copolymer resin (A1). The polyester copolymer resin (A1) had an inherent viscosity of 0.4 dl/g and a glass transition temperature of 90° C. NMR analysis gave the following copolymer composition ratio:
Acid components
Terephthalic acid 71 mol %
Isophthalic acid 29 mol %
Alcohol components
Ethylene glycol 28 mol %
Tricyclodecane dimethanol 72 mol %
A flask was charged with the infrared-absorbing materials, the above-obtained resin and the solvents shown in Table 1 in the proportions indicated therein. The mixture was heated with stirring to dissolve the infrared-absorbing materials and the binder resin in the solvents. The resin solution was applied to a highly transparent polyester film substrate of 100 μm thickness having a slidable surface on one side and a smooth surface on the other side (product of Toyo Boseki K.K., “Cosmoshine A 4100; total light transmittance 90.9%, haze 0.7, coefficient of static friction (slidable surface/smooth surface: 0.58/>1), coefficient of dynamic friction (slidable surface/smooth surface: 0.42/>1)) using an applicator with a gap of 100 μm. The deposited layer was dried at a wind velocity of 0.4 m/s and a temperature of 90° C. in a hot air drier for 1 hour. The resulting coating film had a thickness of 25 μm.
The obtained infrared absorption filter had a color of dark gray when seen. The spectral property qf the filter is shown in FIG. 1. As shown in FIG. 1, the absorption was plotted as flat in the visible light region in the wavelength range of 400 to 650 nm. A difference was 4.8% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm, and the transmittance in the wavelength range was 69.4% at lowest. The sharp absorption was observed in the wavelength range of 700 nm or higher. The transmittance was 23.4% at highest in the wavelength range of 800 to 1100 nm.
The obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the results shown in FIG. 2. While a slight color change occurred, a difference of 9.8% was found between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm and the transmittance in the wavelength range was 65.5% at lowest. The transmittance was 29.1% at highest in the wavelength range of 800 to 1100 nm and the filter retained the near-infrared-absorbing property.
Further, the obtained filter was left to stand in the atmosphere of a temperature of 80° C. for 1000 hours, and the spectral property was evaluated again with the results shown in FIG. 3. While a slight color change was brought about, a difference was 5.8% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm and the transmittance in the wavelength range was 67.2% at lowest. The transmittance was 21.0% at highest in the wavelength range of 800 to 1100 nm and the filter retained the near-infrared-absorbing property.
When disposed in front of a plasma display or the like, the obtained filter showed no change of color and increased the contrast, resulting in reduced level of near-infrared radiation.
TABLE 1
Ingredient Material Amount
Near- Diimmonium salt compound, 3.2 wt. Parts
infrared- Kyasorb IRG-022 manufactured
absorbing by Nippon Kayaku Co., Ltd.
material Fluorine-containing 0.5 wt. Part
phthalocyanine compound,
Excolor IR-1 manufactured by
Nippon Shokubai Co., Ltd.
Dithiol metal complex 1.6 wt. Parts
compound, SIR-159
manufactured by Mitsui Chemicals, Inc.
Binder resin Polyester copolymer resin 440 wt. Parts
(A1)
Solvent Methyl ethyl ketone 490 wt. Parts
Tetrahydrofuran 490 wt. Parts
Toluene 490 wt. Parts
Comparative Example 1
Vylon RV 200 manufactured by Toyo Boseki K.K. (specific weight 1.26, glass transition temp. 67° C.) was used as a base polymer. A flask was charged with the infrared-absorbing materials, the binder resin and the solvents as shown in Table 2 in the proportions indicated therein. These ingredients were heated with stirring to dissolve the the infrared-absorbing materials and the binder resin in the solvents. The resin solution was applied to a highly transparent polyester film substrate of 100 μm thickness (product of Toyo Boseki K.K, “Cosmoshine A 4100”) using an applicator with a gap of 100 μm. The deposited layer was dried at a wind velocity of 0.4 m/s and a temperature of 90° C. in a hot air drier for 1 hour. The resulting coating film had a thickness of 25 μm. The obtained infrared absorption filter had a brown color when seen. As shown by the spectral property of the filter in FIG. 4, the absorption was plotted in a mountain-shaped form having a peak at about 550 nm in the visible light region in the wavelength range of 400 to 650 nm. A difference was 11.5% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm, and the transmittance in the wavelength range was 71.4% at lowest. The sharp absorption was observed in the wavelength range of 700 nm or higher. The transmittance was 44.0% at highest in the wavelength range of 800 to 1100 nm. The filter looked green when seen. When disposed in front of a plasma display or the like, the obtained filter lost a color balance, and turned greenish.
The obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the following results. A difference was increased from 11.5% to 28.6% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm and the transmittance in the wavelength range was 54% at lowest. The transmittance was increased to 49.0% at highest in the wavelength range of 800 to 1100 nm. The filter was deep green when seen. The spectral property is shown in FIG. 5. When disposed in front of a plasma display or the like, the obtained filter lost a color balance, and turned greenish.
Further, the obtained filter was left to stand in the atmosphere of a temperature of 80° C. for 1000 hours, and the spectral property was evaluated again with the following results. A difference rose from 11.5% to 20.3% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm and the transmittance in the wavelength range was 61.8% at lowest. The transmittance was increased to 47.2% at highest in the wavelength range of 800 to 1100 nm. The filter was deep green when seen. The spectral property of the filter is shown in FIG. 6. When disposed in front of a plasma display or the like, the obtained filter lost a color balance, and turned greenish.
TABLE 2
Ingredient Material Amount
Near- Diimmonium salt compound, 3.2 wt. parts
infrared- Kyasorb IRG-022 manufactured
absorbing by Nippon Kayaku Co., Ltd.
material
Binder resin Vylon RV 200 manufactured by 440 wt. parts
Toyo Boseki K.K.
Solvent Methyl ethyl ketone 490 wt. parts
Tetrahydrofuran 490 wt. parts
Toluene 490 wt. parts
Comparative Example 2
Vylon RV 200 (product of Toyo Boseki K.K., specific weight 1.26, glass transition temp. 67° C.) was used as a base polymer. A flask was charged with the infrared-absorbing materials, the binder resin and the solvents as shown in Table 3 in the proportions indicated therein. These ingredients were heated with stirring to dissolve the infrared-absorbing materials and the binder resin in the solvents. The resin solution was applied to a highly transparent polyester film substrate of 100 μm thickness (product of Toyo Boseki K.K., “Cosmoshine A 4100”) using an applicator with a gap of 100 μm. The deposited layer was dried at a wind velocity of 0.4 m/s and a temperature of 90° C. in a hot air drier for 1 hour. The resulting coating film had a thickness of 25 μm.
The obtained infrared absorption filter was dark gray when seen. The spectral property of the filter was substantially the same as in Example 1. The absorption was plotted as flat in the visible light region in the wavelength range of 400 to 650 nm. The sharp absorption was observed at 700 nm or more.
The obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the results shown in FIG. 7. A difference was increased from 4.8% to 27.4% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm, and the transmittance in the wavelength range was 44.0% at lowest. The transmittance was increased to 47.2% at highest in the wavelength range of 800 to 1100 nm. The filter looked green when seen. When disposed in front of a plasma display or the like, the obtained filter lost a color balance, and turned greenish.
Further the obtained filter was left to stand in the atmosphere of a temperature of 80° C. for 1000 hours, and the spectral property was evaluated again with the results shown in FIG. 8. A difference was increased from 4.8% to 16.6% between a maximum value and a minimum value of transmittance in the wavelength range of 450 to 650 nm and the transmittance in the wavelength range was 56.3% at lowest. The transmittance was increased to 30.2% at highest in the wavelength range of 800 to 1000 nm. The filter looked green when seen. When disposed in front of a plasma display or the like, the obtained filter looked green.
TABLE 3
Ingredient Material Amount
Near- Diimmonium salt compound, 3.2 wt. parts
infrared- Kyasorb IRG-022 manufactured
absorbing by Nippon Kayaku Co., Ltd.
material Fluorine-containing 0.5 wt. part
phthalocyanine compound,
Excolor IR-1 manufactured by
Nippon Shokubai Co., Ltd.
Dithiol metal complex 1.6 wt. parts
compound, SIR-159
manufactured by Mitsui Chemicals, Inc.
Binder resin Vylon RV 200 manufactured by 440 wt. parts
Toyo Boseki K.K.
Solvent Methyl ethyl ketone 490 wt. parts
Tetrahydrofuran 490 wt. parts
Toluene 490 wt. parts
EXAMPLE 2
A coating solution was prepared using the polyester copolymer resin (A1) described in Example 1 together with the other ingredients shown in Table 1 in the proportions indicated therein. The coating solution thus obtained was applied to a highly transparent polyester film substrate of 100 μm thickness (product of Toyo Boseki K.K., “Cosmoshine A 4300”, total transmittance 90.9% haze 0.7, coefficient of static friction (both surfaces) 0.58, coefficient of dynamic friction (both surfaces) 0.42) by a gravure roll. The deposited layer was dried for 1 minute by feeding hot air at a wind velocity of 5 m/s and a temperature of 130° C. and then the filter was wound into a roll. The resulting coating layer had a thickness of 8.0 pm. The amount of residual solvents in the coating layer was 4.1 wt. %. The filter had a high slidability and showed a good roll appearance.
The obtained infrared absorption filter looked dark gray when seen. The spectral property of the filter is shown in FIG. 9. As shown in FIG. 9, the absorption was plotted as flat in the visible light region in the wavelength range of 400 to 650 nm. The sharp absorption was observed at a wavelength of 700 nm or more.
The obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the results shown in FIG. 10. The filter showed no great change in the spectral curve and exhibited stable performance.
Comparative Example 3
The coating solution used in Example 1 was applied to a highly transparent polyester film substrate (product to Toyo Boseki K.K., “Cosmoshine A 4300”) by a gravure roll. The deposited layer was dried for 1 minute by feeding hot air at a wind velocity of 5 m/s and a temperature of 120° C. The coating layer had a thickness of 11 μm. The amount of residual solvents in the coating layer was 6.5 wt. %. The filter looked dark gray when seen. The spectral property of the filter is shown in FIG. 11. As shown in FIG. 11, the absorption was plotted as flat in the visible light region in the wavelength range of 450 to 650 nm. The sharp absorption was observed at a wavelength of 700 nm or more.
The obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the results shown in FIG. 12. As indicated in FIG. 12, the absorption in the near-infrared region lowered and the color of the filter turned yellowish green.
EXAMPLE 3
In the transparent polyester film having the infrared-absorbing layer as obtained in Example 2, a hard coat-treated layer (HC) was formed on the surface of the side opposed to the infrared-absorbing layer. Used as a hard coat material was a UV-curable resin composition comprising 100 parts of an epoxy acrylic resin and 4 parts of benzophenone. The hard coat-treated layer was formed by a bar coat method. Then, preliminary drying was conducted at 80° C. for 5 minutes and the layer was cured by UV radiation with 500 mJ/cm2. The cured hard coat-treated layer (HC) had a thickness of 5 μm.
Copper foil of 9 μm thickness was bonded to the surface of infrared-absorbing layer with a UV-curing adhesive, the bonded copper foil was patterned with photoresist and etched to give a an electromagnetic wave shielding layer. The copper foil had lines of 15 μm width, a pitch of 115 μm and an aperture ratio of 75%
FIG. 13 shows the spectral property of the filter having, as described above, the hard coat-treated layer on one side of the transparent polyester film substrate, and the infrared-absorbing layer and the electromagnetic wave shielding layer superposed in this order on the other side thereof. As shown in FIG. 13, it was found that the filter can absorb near-infrared rays, has a gray color and exhibits a high visible light transmission while absorbing an electromagnetic wave.
The obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the following results. Although a little changed in color, the filter maintained the near-infrared absorbing property. When disposed in front of a plasma display or the like, the obtained filter did not undergo change of color and increased the contrast, resulting in the decrease in radiation of near-infrared beams and in radiation of electromagnetic wave.
EXAMPLE 4
In the transparent polyester film having an infrared-absorbing layer as obtained in Example 2, a hard coat-treated layer (HC) was formed on the surface of the side opposed to the infrared-absorbing layer. Used as a hard coat material was a UV-curing resin composition comprising 100 parts of an epoxy acrylic resin and 4 parts of benzophenone. The hard coat-treated layer was formed by a bar coat method. Then, preliminary drying was conducted at 80° C. for 5 minutes and the layer was cured by UV radiation with 500 mJ/cm2. The cured hard coat-treated layer (HC) had a thickness of 5 μm.
A thin film of tin oxide with 380 Å0 thickness was formed on the infrared-absorbing layer by a high-frequency magnetron sputtering device. Then a thin film of silver with 200 Å thickness was laminated on said thin film by a DC magnetron sputtering device. Further a thin film of tin oxide with 410 Å thickness was laminated thereon to form a electromagnetic wave shielding layer. The electromagnetic wave shielding layer had a surface resistance value of 4 Ω/□. FIG. 14 shows the spectral property of the filter having, as described above, the hard coat-treated layer on one side of the transparent polyester film substrate, and the infrared-absorbing layer and the electromagnetic wave shielding layer laminated in this order on the other side thereof. As shown in FIG. 14, the filter can absorb near-infrared rays, has a gray color, and exhibits a high visible light transmission while absorbing the electromagnetic wave.
The obtained filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours, and the spectral property was evaluated again with the following results. Although a little changed in color, the filter maintained the near-infrared absorbing property. When disposed in front of a plasma display or the like, the obtained filter did not undergo change of color and increased the contrast, resulting in the decrease in radiation of near-infrared beams and in radiation of electromagnetic wave.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the spectral property of the infrared absorption filter prepared in Example 1.
FIG. 2 shows the spectral property of the infrared absorption filter prepared in Example 1 after the filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours.
FIG. 3 shows the spectral property of the infrared absorption filter prepared in Example 1 after the filter was left to stand in the atmosphere of a temperature of 80° C. for 1000 hours.
FIG. 4 shows the spectral property of the infrared absorption filter prepared in Comparative Example 1.
FIG. 5 shows the spectral property of the infrared absorption filter prepared in Comparative Example 1 after the filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours.
FIG. 6 shows the spectral property of the infrared absorption filter prepared in Comparative Example 1 after the filter was left to stand in the atmosphere of a temperature of 80° C. for 1000 hours.
FIG. 7 shows the spectral property of the infrared absorption filter prepared in Comparative Example 2 after the filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours.
FIG. 8 shows the spectral property of thy infrared absorption filter prepared in Comparative Example 2 after the filter was left to stand in the atmosphere of a temperature of 80° C. for 1000 hours.
FIG. 9 shows the spectral property of the infrared absorption filter prepared in Example 2.
FIG. 10 shows the spectral property of the infrared absorption filter prepared in Example 2 after the filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours.
FIG. 11 shows the spectral property of the infrared absorption filter prepared in Comparative Example 3.
FIG. 12 shows the spectral property of the infrared absorption filter prepared in Comparative Example 3 after the filter was left to stand in the atmosphere of a temperature of 60° C. and a humidity of 95% for 1000 hours.
FIG. 13 shows the spectral property of the infrared absorption filter prepared in Example 3.
FIG. 14 shows the spectral property of the infrared absorption filter prepared in Example 4.
 EFFECTS OF THE INVENTION
The infrared absorption filter of the present invention has broad absorption in the near-infrared region, shows a high visible light transmission and does not markedly absorb a specific light in the visible light wavelengths. When used for a plasma display or the like, the filter can absorb the unwanted infrared radiation emitted from the display, thereby making it possible to prevent erroneous operational of a remote control using infrared radiation. The infrared absorption filter of the present invention is gray in color so that it is unlikely to cause color change when used for a video camera, display or the like. Further the filter of the invention has such a high environmental stability that the filter can maintain said properties in an environment of a high temperature and a high humidity.

Claims (27)

1. An infrared absorption filter which has a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm;
a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm; and
a transmittance of not lower than 50% at a wavelength of 550 nm,
said filter, after being left to stand in the air atmosphere at a temperature of 60° C. and a humidity of 95% for 1000 hours, having
a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm, and
a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm,
said filter having an infrared-absorbing layer on a transparent substrate,
the infrared-absorbing layer being composed of a coloring matter, dye or pigment absorbing infrared radiation and a polymer serving as a dispersing medium and
the transparent substrate having a total light transmittance of not lower than 89%, a haze of not higher than 1.6%, a coefficient of static friction of not higher than 0.6 and a coefficient of dynamic friction of not higher than 0.6.
2. The infrared absorption filter according to claim 1, wherein after being left to stand in the air atmosphere at a temperature of 80° C. for 1000 hours, the filter has a transmittance of not higher than 30% in the near-infrared region in the wavelength of 800 to 1100 nm and has a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength of 450 to 650 nm.
3. The infrared absorption filter according to claim 1, wherein the amount of a solvent remaining in the infrared-absorbing layer is 5.0 wt. % or less.
4. The infrared absorption filter according to claim 1, wherein the transparent substrate is a polyester film.
5. The infrared absorption filter according to claim 1, wherein the polymer constituting the infrared-absorbing layer has a glass transition temperature of not lower than 80° C.
6. The infrared absorption filter according to claim 5, wherein the polymer constituting the infrared-absorbing layer is a polyester resin.
7. The infrared absorption filter according to claim 1, wherein the filter has an electroconductive layer of metal mesh having an aperture ratio of not less than 50% on the same side as the infrared-absorbing layer of the filter or on the opposed side thereof.
8. The infrared absorption filter according to claim 1, wherein the filter has a transparent electroconductive layer on the same side as the infrared-absorbing layer of the filter or on the opposed side thereof.
9. The infrared absorption filter according to claim 8, wherein the transparent electroconductive layer is formed of a metal oxide.
10. The infrared absorption filter according to claim 8, wherein the transparent electroconductive layer has a repeatedly laminated structure in which at least three layers are laminated in the order of metal oxide/metal/metal oxide.
11. The infrared absorption filter according to claim 10, wherein the constituent metal layer of the transparent electroconductive layer is formed of silver, gold or a compound containing any of them.
12. The infrared absorption filter according to claim 1, wherein a hard coat-treated layer is formed as an outermost layer of the filter.
13. The infrared absorption filter according to claim 1, wherein an antireflection layer is formed as an outermost layer of the filter.
14. The infrared absorption filter according to claim 1, wherein an antiglare-treated layer is formed as an outermost layer on the filter.
15. The infrared absorption filter according to claim 1, wherein the filter is disposed in front of a plasma display.
16. An infrared absorption filter which has a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm;
a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm; and
a transmittance of not lower than 50% at a wavelength of 550 nm,
said filter, after being left to stand in the air atmosphere at a temperature of 60° C. and a humidity of 95% for 1000 hours, having
a transmittance of not higher than 30% in the near-infrared region in the wavelength range of 800 to 1100 nm, and
a difference of 10% or less between a maximum value and a minimum value of transmittance in the visible light region in the wavelength range of 450 to 650 nm,
said filter comprising a transparent substrate and an infrared-absorbing layer formed thereon,
the filter being prepared by coating the transparent substrate with a coating solution comprising an infrared-absorbing material, a binder resin and at least one solvent, and
the transparent substrate having a total light transmittance of not lower than 89%, a haze of not higher than 1.6%, a coefficient of static friction of not higher than 0.6 and a coefficient of dynamic friction of not higher than 0.6.
17. The infrared absorption filter according to claim 16, wherein the amount of the solvent remaining in the infrared-absorbing layer is 5.0 wt. % or less.
18. The infrared absorption filter according to claim 16, wherein the transparent substrate is a polyester film.
19. The infrared absorption filter according to claim 16, wherein the filter has an electroconductive layer of metal mesh having an aperture ratio of not less than 50% on the same side as the infrared-absorbing layer of the filter or on the opposed side thereof.
20. The infrared absorption filter according to claim 16, wherein the filter has a transparent electroconductive layer on the same side as the infrared-absorbing layer of the filter or on the opposed side thereof.
21. The infrared absorption filter according to claim 20, wherein the transparent electroconductive layer is formed of a metal oxide.
22. The infrared absorption filter according to claim 20, wherein the transparent electroconductive layer has a repeatedly laminated structure in which at least three layers are laminated in the order of metal oxide/metal/metal oxide.
23. The infrared absorption filter according to claim 20, wherein the constituent metal layer of the transparent electroconductive layer is formed of silver, gold or a compound containing any of them.
24. The infrared absorption filter according to claim 16, wherein a hard coat-treated layer is formed as an outermost layer of the filter.
25. The infrared absorption filter according to claim 16, wherein an antireflection layer is formed as an outermost layer of the filter.
26. The infrared absorption filter according to claim 16, wherein an antiglare-treated layer is formed as an outermost layer of the filter.
27. The infrared absorption filter according to claim 16, wherein the filter is disposed in front of a plasma display.
US10/897,394 1998-05-15 1999-05-17 Infrared absorption filter Expired - Fee Related USRE39858E1 (en)

Applications Claiming Priority (7)

Application Number Priority Date Filing Date Title
JP13303098A JPH11326629A (en) 1998-05-15 1998-05-15 Infrared absorption filter
JP13303198A JPH11326630A (en) 1998-05-15 1998-05-15 Infrared-ray absorbing filter
JP10193028A JP2000028826A (en) 1998-07-08 1998-07-08 Ir absorbing filter
JP10193027A JP2000028825A (en) 1998-07-08 1998-07-08 Ir absorbing filter
JP10251083A JP2000081510A (en) 1998-09-04 1998-09-04 Ir absorbing filter
JP34436598 1998-12-03
PCT/JP1999/002554 WO1999060430A1 (en) 1998-05-15 1999-05-17 Infrared absorption filter

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US09/700,299 Reissue US6522463B1 (en) 1998-05-15 1999-05-17 Infrared absorption filter

Publications (1)

Publication Number Publication Date
USRE39858E1 true USRE39858E1 (en) 2007-09-25

Family

ID=27552806

Family Applications (3)

Application Number Title Priority Date Filing Date
US09/700,299 Ceased US6522463B1 (en) 1998-05-15 1999-05-17 Infrared absorption filter
US10/897,393 Expired - Lifetime USRE39857E1 (en) 1998-05-15 1999-05-17 Infrared absorption filter
US10/897,394 Expired - Fee Related USRE39858E1 (en) 1998-05-15 1999-05-17 Infrared absorption filter

Family Applications Before (2)

Application Number Title Priority Date Filing Date
US09/700,299 Ceased US6522463B1 (en) 1998-05-15 1999-05-17 Infrared absorption filter
US10/897,393 Expired - Lifetime USRE39857E1 (en) 1998-05-15 1999-05-17 Infrared absorption filter

Country Status (5)

Country Link
US (3) US6522463B1 (en)
EP (2) EP1482332B1 (en)
KR (3) KR100429076B1 (en)
DE (2) DE69932521T8 (en)
WO (1) WO1999060430A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070195417A1 (en) * 2004-03-12 2007-08-23 Yoshiharu Yamamoto Light-absorbing member
US20160165214A1 (en) * 2014-12-08 2016-06-09 Lg Innotek Co., Ltd. Image processing apparatus and mobile camera including the same

Families Citing this family (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100444332B1 (en) * 1999-12-20 2004-08-16 도요 보세키 가부시키가이샤 Infrared absorption filter
US6680009B2 (en) * 2000-07-06 2004-01-20 Fuji Photo Film Co., Ltd. Optical filter comprising transparent support and filter layer having three absorption maximums
JP3517210B2 (en) * 2000-12-28 2004-04-12 日清紡績株式会社 Near infrared absorbing material
JP3893533B2 (en) * 2001-02-09 2007-03-14 株式会社日立製作所 Liquid crystal display
DE60232603D1 (en) 2001-06-21 2009-07-23 Teijin Ltd Near-PROTECTION
JP2003004939A (en) * 2001-06-25 2003-01-08 Asahi Glass Co Ltd Optical film
KR100481090B1 (en) * 2002-09-05 2005-04-07 (주)해빛정보 Near infrared absorption filter
US7245079B2 (en) * 2003-05-28 2007-07-17 Solutia Incorporated Plasma display panel filters comprising multiple layers
US20040239251A1 (en) * 2003-05-28 2004-12-02 D'haene Pol Plasma display panel filters
KR100515594B1 (en) * 2003-07-11 2005-09-21 주식회사 엘지화학 Near infrared absorbing film and plasma display filter comprising the same
EP1656572A1 (en) * 2003-08-19 2006-05-17 LG Chem, Ltd. Film for plasma display filter and plasma display filter comprising the same
JP4800769B2 (en) * 2003-11-10 2011-10-26 日本化薬株式会社 Diimonium salt compounds and uses thereof
KR100658852B1 (en) * 2004-05-17 2006-12-15 엘지전자 주식회사 Plasma display apparatus
EP1808461B1 (en) * 2004-07-15 2009-03-11 Teijin Chemicals, Ltd. Resin composition and molded object thereof
US20060051586A1 (en) * 2004-08-28 2006-03-09 Park Sang H Film for PDP filter, PDP filter comprising the same and plasma display panel produced by using the PDP filter
CN101010290B (en) * 2004-09-06 2011-08-03 日本化药株式会社 Diimmonium compound and use thereof
KR101024881B1 (en) 2005-02-04 2011-03-31 니폰 쇼쿠바이 컴파니 리미티드 Borate and near-infrared ray absorption material
CN101124287B (en) * 2005-02-22 2011-01-05 旭硝子株式会社 Adhesive composition, pressure-sensitive adhesive film, and optical filter
JP2006310195A (en) * 2005-04-28 2006-11-09 Tdk Corp Transparent conductor
WO2006118277A1 (en) * 2005-04-28 2006-11-09 Api Corporation Pressure-sensitive adhesive containing near infrared absorbing coloring matter
US20070001566A1 (en) * 2005-06-30 2007-01-04 D Haene Pol Impact resistant, direct contact plasma display panel filters
US7510456B2 (en) * 2005-06-30 2009-03-31 Solutia Incorporated Method of making impact resistant, direct contact plasma display panel filters
KR100768200B1 (en) * 2006-02-01 2007-10-17 삼성에스디아이 주식회사 Optical filter and plasma display panel employing the same
US7655306B2 (en) 2006-05-23 2010-02-02 Cheil Industries, Inc. Optical film, optical filter and display device including the same
US7833660B1 (en) 2006-09-07 2010-11-16 The United States Of America As Represented By The Secretary Of The Army Fluorohaloborate salts, synthesis and use thereof
US7820323B1 (en) 2006-09-07 2010-10-26 The United States Of America As Represented By The Secretary Of The Army Metal borate synthesis process
KR100854689B1 (en) * 2007-05-28 2008-08-27 손세모 Coloring matter absorbing near-infrared ray and filter for cutting off near-infrared ray using thereof
FR2935585B1 (en) * 2008-09-01 2015-04-24 Sagem Comm FACADE OF ELECTRONIC APPARATUS ADAPTED AGAINST RADIATION OF INFRARED RADIATION TYPE.
WO2012027711A2 (en) 2010-08-26 2012-03-01 University Of Louisville Research Foundation, Inc. Compositions and methods for treating bone defects
US20130063602A1 (en) * 2011-09-12 2013-03-14 Bruce Scapier System and method for remote monitoring of equipment moisture exposure
JP5224203B1 (en) 2012-07-11 2013-07-03 大日本印刷株式会社 Touch panel sensor, touch panel device, and display device
AU2014331971B2 (en) 2013-10-08 2018-07-19 Vivorte, Inc. Processed bone particle compositions and related methods
US10564780B2 (en) 2015-08-21 2020-02-18 3M Innovative Properties Company Transparent conductors including metal traces and methods of making same
WO2018163766A1 (en) * 2017-03-09 2018-09-13 富士フイルム株式会社 Structure, kit, and optical sensor
CN112467391B (en) * 2020-11-16 2021-12-31 北京航空航天大学 Inhale and pass through integrative controllable electromagnetic protection material

Citations (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3575871A (en) 1963-05-16 1971-04-20 American Cyanamid Co Tetraaryl arylaminium salts and use as infrared absorbers
JPS5521091A (en) 1978-08-02 1980-02-14 American Optical Corp Interference filter
JPS5721458A (en) 1980-07-11 1982-02-04 Mitsubishi Electric Corp Near infrared absorbing plastic film
JPS57198413A (en) 1981-05-30 1982-12-06 Mitsui Toatsu Chem Inc Optical filter having spectral characteristic close to visibility
JPS59184745A (en) 1983-03-25 1984-10-20 フラツハグラ−ス，アクチエンゲゼルシヤフト Method of coating transparent substrate
US4497700A (en) 1983-03-25 1985-02-05 Flachglas Aktiengesellschaft Method of coating a transparent substrate
JPS6043605A (en) 1983-08-22 1985-03-08 Nippon Kayaku Co Ltd Near infrared absorption filter
JPS60235740A (en) 1984-04-18 1985-11-22 シヨツト　グラスヴエルケ Glass for optical colored filter
JPS62153144A (en) 1985-12-25 1987-07-08 Toshiba Glass Co Ltd Near infrared cutting filter glass and production thereof
US4816386A (en) * 1986-01-13 1989-03-28 Toray Industries, Inc. Near-infrared sensitive phthalocyanine-polymer compositions
JPH06324213A (en) 1993-04-28 1994-11-25 Kureha Chem Ind Co Ltd Composite optical filter
JPH07134209A (en) 1993-11-10 1995-05-23 Kureha Chem Ind Co Ltd Near infrared radiation cutting filter
US5466755A (en) 1992-08-20 1995-11-14 Kureha, Kagaku Kogyo Kabushiki Kaisha Optical filter
JPH07314626A (en) 1994-05-24 1995-12-05 Diafoil Co Ltd Composite polyester film
JPH08106059A (en) * 1994-10-06 1996-04-23 Olympus Optical Co Ltd Light source optical system for endoscope
WO1997038855A1 (en) 1996-04-18 1997-10-23 Kanebo, Limited Near infrared ray absorption film and multi-layered panel including same
JPH09306366A (en) 1996-05-07 1997-11-28 Fujitsu General Ltd Optical filter device
JPH1078509A (en) 1996-07-12 1998-03-24 Mitsui Petrochem Ind Ltd Filter for plasma display
JPH10105076A (en) 1996-09-26 1998-04-24 Nof Corp Near infrared shielding filter for electronic display
EP0838475A2 (en) 1996-10-23 1998-04-29 Sumitomo Chemical Company, Limited Plasma display front panel
US5804102A (en) 1995-12-22 1998-09-08 Mitsui Chemicals, Inc. Plasma display filter

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SG52477A1 (en) * 1991-04-26 1998-09-28 Mitsui Chemicals Inc Optical recording medium
KR100444332B1 (en) * 1999-12-20 2004-08-16 도요 보세키 가부시키가이샤 Infrared absorption filter
JP4254069B2 (en) * 2001-03-14 2009-04-15 パナソニック電工株式会社 Manufacturing method of near-infrared cut material
US20050163958A1 (en) * 2003-11-13 2005-07-28 Yuji Nakatsugawa Optical filter and display using the same

Patent Citations (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3575871A (en) 1963-05-16 1971-04-20 American Cyanamid Co Tetraaryl arylaminium salts and use as infrared absorbers
US3575871B1 (en) 1963-05-16 1986-04-08
JPS5521091A (en) 1978-08-02 1980-02-14 American Optical Corp Interference filter
US4223974A (en) 1978-08-02 1980-09-23 American Optical Corporation Enhanced bonding of silicon oxides and silver by intermediate coating of metal
JPS5721458A (en) 1980-07-11 1982-02-04 Mitsubishi Electric Corp Near infrared absorbing plastic film
JPS57198413A (en) 1981-05-30 1982-12-06 Mitsui Toatsu Chem Inc Optical filter having spectral characteristic close to visibility
JPS59184745A (en) 1983-03-25 1984-10-20 フラツハグラ−ス，アクチエンゲゼルシヤフト Method of coating transparent substrate
US4497700A (en) 1983-03-25 1985-02-05 Flachglas Aktiengesellschaft Method of coating a transparent substrate
JPS6043605A (en) 1983-08-22 1985-03-08 Nippon Kayaku Co Ltd Near infrared absorption filter
JPS60235740A (en) 1984-04-18 1985-11-22 シヨツト　グラスヴエルケ Glass for optical colored filter
US4615989A (en) 1984-04-18 1986-10-07 Schott Glaswerke Optical quality colored glass
JPS62153144A (en) 1985-12-25 1987-07-08 Toshiba Glass Co Ltd Near infrared cutting filter glass and production thereof
US4816386A (en) * 1986-01-13 1989-03-28 Toray Industries, Inc. Near-infrared sensitive phthalocyanine-polymer compositions
US5466755A (en) 1992-08-20 1995-11-14 Kureha, Kagaku Kogyo Kabushiki Kaisha Optical filter
JPH06324213A (en) 1993-04-28 1994-11-25 Kureha Chem Ind Co Ltd Composite optical filter
JPH07134209A (en) 1993-11-10 1995-05-23 Kureha Chem Ind Co Ltd Near infrared radiation cutting filter
JPH07314626A (en) 1994-05-24 1995-12-05 Diafoil Co Ltd Composite polyester film
JPH08106059A (en) * 1994-10-06 1996-04-23 Olympus Optical Co Ltd Light source optical system for endoscope
US5804102A (en) 1995-12-22 1998-09-08 Mitsui Chemicals, Inc. Plasma display filter
WO1997038855A1 (en) 1996-04-18 1997-10-23 Kanebo, Limited Near infrared ray absorption film and multi-layered panel including same
US6255031B1 (en) 1996-04-18 2001-07-03 Kanebo, Ltd. Near infrared absorbing film, and multi-layered panel comprising the film
JPH09306366A (en) 1996-05-07 1997-11-28 Fujitsu General Ltd Optical filter device
JPH1078509A (en) 1996-07-12 1998-03-24 Mitsui Petrochem Ind Ltd Filter for plasma display
JPH10105076A (en) 1996-09-26 1998-04-24 Nof Corp Near infrared shielding filter for electronic display
EP0838475A2 (en) 1996-10-23 1998-04-29 Sumitomo Chemical Company, Limited Plasma display front panel

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Communication from the European Patent Office herewith transmits as an enclosure the European search report (under R. 44 or R. 45 EPC) for the European Patent Application No. 04018016.8-2217 PCT.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070195417A1 (en) * 2004-03-12 2007-08-23 Yoshiharu Yamamoto Light-absorbing member
US20160165214A1 (en) * 2014-12-08 2016-06-09 Lg Innotek Co., Ltd. Image processing apparatus and mobile camera including the same

Also Published As

Publication number Publication date
KR20010043580A (en) 2001-05-25
DE69942918D1 (en) 2010-12-16
KR20040020981A (en) 2004-03-09
US6522463B1 (en) 2003-02-18
EP1087243A1 (en) 2001-03-28
KR100446049B1 (en) 2004-08-30
USRE39857E1 (en) 2007-09-25
KR20040020982A (en) 2004-03-09
DE69932521T8 (en) 2007-08-02
KR100441301B1 (en) 2004-07-23
EP1482332B1 (en) 2010-11-03
DE69932521T2 (en) 2007-02-08
KR100429076B1 (en) 2004-04-29
EP1087243B1 (en) 2006-07-26
EP1482332A2 (en) 2004-12-01
EP1087243A4 (en) 2002-05-29
DE69932521D1 (en) 2006-09-07
WO1999060430A1 (en) 1999-11-25
EP1482332A3 (en) 2005-09-21

Similar Documents

Publication Publication Date Title
USRE39858E1 (en) Infrared absorption filter
EP1441239B1 (en) Transparent laminate, method for producing the same, and plasma display panel
US7662490B2 (en) Near-infrared shield and display front plate
US7071602B2 (en) Filter for plasma display panel
JP3341741B2 (en) Near infrared absorption filter
US20070020470A1 (en) Optical film and image display apparatus panel using the same
JP2000081510A (en) Ir absorbing filter
JP5165689B2 (en) Optical filter for display panel and manufacturing method thereof
JP2012093481A (en) Near-infrared light reflection film and near-infrared light reflector having the same
JP2000147244A (en) Optical filter
US6770344B2 (en) Functional laminated film, its production process and CRT having said film attached thereto
JP2004012592A (en) Near infrared ray absorption and antireflection combined functional film
JP2002303720A (en) Near ir ray absorbing filter
JP2001133623A (en) Ir- absorbing filter
US11892663B2 (en) Article including a wavelength selective absorbing material
JP2000028825A (en) Ir absorbing filter
JP2000028826A (en) Ir absorbing filter
KR100513642B1 (en) Optical filter for plasma display panel and manufacturing method thereof
JP3812590B2 (en) Near-infrared absorbing filter and manufacturing method thereof
JP2005301300A (en) Method of manufacturing near ir absorption filter, and method for using near ir absorption filter
JP2000238169A (en) Manufacture of transparent conductive film
JP2005043921A (en) Near infrared ray absorbing filter
JP2006139274A (en) Method of manufacturing near ir absorption filter, and method for using near ir absorption filter
JPH10211668A (en) Infrared ray absorption film
JP2005099820A (en) Near infrared ray absorption filter

Legal Events

Date Code Title Description
AS Assignment

Owner name: SCIMED LIFE SYSTEMS, INC., MINNESOTA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:RICHARD, ROBERT E.;FAUST, RUDOLF;REEL/FRAME:015324/0359;SIGNING DATES FROM 20040818 TO 20040819

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 8

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees