Infrared absorption filter

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.

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 of 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 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 a solvent,    the binder resin being selected from polyester resins, acrylic resins, polyamide resins, polyurethane resins, polyolefin resins and polycarbonate resins, and    the amount of the solvent remaining in the infrared-absorbing layer being  5 . 0  wt. % or less.   
     
     
       17. The infrared absorption filter according to  claim 16 , wherein the binder resin has a glass transition temperature of not lower than  80 ° C. 
     
     
       18. The infrared absorption filter according to  claim 16 , wherein the binder resin is a polyester resin. 
     
     
       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 22 , 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. 
     
     
       28. The infrared absorption filter according to  claim 16 , wherein 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
 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 has a transmittance of not higher than  30 % in the near-infrared region in the wavelength range of  800  to  1100  nm.   
     
     
       29. The infrared absorption filter according to  claim 28 , wherein the filter has a difference of  10 % or less between the maximum value and the 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, and
 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 has a difference of  10 % or less between the maximum value and the minimum value of transmittance in the visible light region in the wavelength range of  450  to  650  nm.   
     
     
       30. The infrared absorption filter according to  claim 16 , wherein 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
 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 range of  800  to  1100  nm.   
     
     
       31. The infrared absorption filter according to  claim 30 , wherein the filter has a difference of  10 % or less between the maximum value and the 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, and
 after being left to stand in the air atmosphere at a temperature of  80 ° C. for  1000  hours, the filter has a difference of  10 % or less between the maximum value and the minimum value or transmittance in the visible light region in the wavelength range of  450  to  650  nm.   
     
     
       32. The infrared absorption filter according to  claim 16 , wherein the infrared-absorbing material contains a dimmonium salt compound. 
     
     
       33. The infrared absorption filter according to  claim 32 , wherein the dimmonium salt compound is 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.   
     
     
       34. The infrared absorption filter according to  claim 16 , wherein the infrared-absorbing material contains at least two species of dimmonium salt compound, fluorine-containing phthalocyanine compound and nickel complex compound.