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US-12617948-B2 - Liquid composition for optical filters and optical filter

US12617948B2US 12617948 B2US12617948 B2US 12617948B2US-12617948-B2

Abstract

The liquid composition for optical filters according to the present invention contains: a light absorber; at least one of an alkoxysilane and a hydrolysate of an alkoxysilane; a phosphoric acid ester; and a solvent. The light absorber is formed by a phosphonic acid having an aryl group bonded to a phosphorus atom and copper ion. In the liquid composition, a content of an organic solvent having a relative permittivity of 7 or less at 20° C. is 50 mass % or less.

Inventors

  • Yuichiro Kubo
  • Lei Cai
  • Hitomi Masuda
  • Katsuhide Shimmo

Assignees

  • NIPPON SHEET GLASS COMPANY, LIMITED

Dates

Publication Date
20260505
Application Date
20240924
Priority Date
20180911

Claims (18)

  1. 1 . A composition comprising: a light absorber including a phosphonic acid and a copper ion; a phosphoric acid ester at least one selected from the group consisting of a first phosphoric acid ester represented by the following formula (c1) and a second phosphoric acid ester represented by the following formula (c2); a curable resin; and a solvent including a first organic solvent that has a relative permittivity of 7 or less at 20° C., and a second organic solvent that has a relative permittivity of more than 7 at 20° C., wherein a mass ratio of the first organic solvent to the composition is 20% or less in formulae (cl) and (c2), R 21 , R 22 , and R 3 are each a monovalent functional group represented by -(CH 2 CH 2 O) n R 4 , wherein n is an integer of 1 to 25, R 4 is an alkyl group having 6 to 25 carbon atoms, and R 21 , R 22 , and R 3 may be the same or different functional groups.
  2. 2 . The composition according to claim 1 , wherein the phosphonic acid has an aryl group bonded to a phosphorus atom.
  3. 3 . The composition according to claim 1 , wherein a transmitted light incident on the composition has a transmittance spectrum that satisfies the following requirements (i) and (ii): (i) the spectral transmittance increases with increasing wavelength in a wavelength range of 350 nm to 450 nm and an ultraviolet cut-off wavelength which lies in the wavelength range of 350 nm to 450 nm and at which the transmittance is 50% is in a wavelength range of 380 nm to 420 nm; and (ii) the spectral transmittance decreases with increasing wavelength in a wavelength range of 600 nm to 800 nm and an infrared cut-off wavelength which lies in the wavelength range of 600 nm to 800 nm and at which the transmittance is 50% is in a wavelength range of 600 nm to 690 nm.
  4. 4 . The composition according to claim 3 , wherein the average transmittance in a wavelength range of 300 nm to 350 nm is 1% or less in the transmittance spectrum.
  5. 5 . The composition according to claim 3 , wherein the average transmittance in a wavelength range of 300 nm to 370 nm is 2% or less in the transmittance spectrum.
  6. 6 . The composition according to claim 3 , wherein the average transmittance in a wavelength range of 400 nm to 600 nm is 70% or more in the transmittance spectrum.
  7. 7 . The composition according to claim 3 , wherein the average transmittance in a wavelength range of 450 nm to 600 nm is 70% or more in the transmittance spectrum.
  8. 8 . The composition according to claim 3 , wherein the transmittance at a wavelength of 800 nm is 20% or less in the transmittance spectrum.
  9. 9 . The composition according to claim 3 , wherein the transmittance at a wavelength of 900 nm is 25% or less in the transmittance spectrum.
  10. 10 . The composition according to claim 3 , wherein the transmittance at a wavelength of 1100 nm is 45% or less in the transmittance spectrum.
  11. 11 . The composition according to claim 3 , wherein the transmittance at a wavelength of 1300 nm is 70% or less in the transmittance spectrum.
  12. 12 . The composition according to claim 1 , wherein the phosphoric acid ester has an HLB value of 7 to 16.
  13. 13 . The composition according to claim 1 , further comprising at least one selected from the group consisting of an alkoxysilane and a hydrolysate of an alkoxysilane, the alkoxysilane and the hydrolysate of an alkoxysilane having a non-reactive hydrophobic group bonding to a silicon atom.
  14. 14 . An optical filter comprising: a transparent substrate; and a light-absorbing film including a cured product of the composition according to claim 1 , the light-absorbing film having a thickness of 40 μm to 250 μm, wherein a transmitted light incident on the optical filter has a transmittance spectrum that satisfies the following requirements (I) and (II): (I) the spectral transmittance increases with increasing wavelength in a wavelength range of 350 nm to 450 nm and an ultraviolet cut-off wavelength which lies in the wavelength range of 350 nm to 450 nm and at which the transmittance is 50% is in a wavelength range of 380 nm to 420 nm; and (II) the spectral transmittance decreases with increasing wavelength in a wavelength range of 600 nm to 800 nm and an infrared cut-off wavelength which lies in the wavelength range of 600 nm to 800 nm and at which the transmittance is 50% is in a wavelength range of 600 nm to 690 nm.
  15. 15 . The optical filter according to claim 14 wherein the transmittance spectrum satisfies at least one selected from the group consisting of the following requirements (Ia) and (IIa): (Ia) the average transmittance in a wavelength range of 300 nm to 350 nm is 1% or less in the transmittance spectrum; and (IIa) the average transmittance in a wavelength range of 300 nm to 370 nm is 3% or less in the transmittance spectrum.
  16. 16 . The optical filter according to claim 14 , wherein the transmittance spectrum satisfies at least one selected from the group consisting of the following requirements (Ib) and (IIb): (Ib) the average transmittance in a wavelength range of 400 nm to 600 nm is 70% or more in the transmittance spectrum; and (IIb) the average transmittance in a wavelength range of 450 nm to 600 nm is 70% or more in the transmittance spectrum.
  17. 17 . The optical filter according to claim 14 , wherein the transmittance spectrum satisfies at least one selected from the group consisting of the following requirements (IIIa), (IIIb), and (IIIc): (IIIa) the transmittance at a wavelength of 800 nm is 25% or less in the transmittance spectrum; (IIIb) the transmittance at a wavelength of 900 nm is 25% or less in the transmittance spectrum; and (IIIc) the transmittance at a wavelength of 1100 nm is 60% or less in the transmittance spectrum.
  18. 18 . The optical filter according to claim 14 , wherein the transparent substrate has a transmittance of 70% or more in a wavelength range of 450 nm to 600 nm.

Description

TECHNICAL FIELD The present invention relates to a liquid composition for optical filters and an optical filter. BACKGROUND ART In imaging apparatuses employing a solid-state imaging sensor such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), any of various optical filters is disposed ahead of the solid-state imaging sensor in order to obtain images with good color reproduction. Solid-state imaging sensors generally have spectral sensitivity over a wide wavelength range from the ultraviolet to infrared regions. On the other hand, the visual sensitivity of humans lies solely in the visible region. Thus, a technique is known in which an optical filter blocking a portion of infrared light or ultraviolet light is disposed ahead of a solid-state imaging sensor in an imaging apparatus in order to allow the spectral sensitivity of the solid-state imaging sensor to approximate to the visual sensitivity of humans. It has been common for such an optical filter to block infrared light or ultraviolet light by means of light reflection by a dielectric multilayer film. In recent years, optical filters including a light absorber-including film have been attracting attention. The transmittance properties of optical filters including a light absorber-including film are unlikely to be dependent on the incident angle, and this makes it possible to obtain favorable images with less color change even when light is obliquely incident on the optical filters in imaging apparatuses. Moreover, optical filters including a light absorber-including film are advantageous also in terms of reducing the size and thickness of imaging apparatuses. For example, Patent Literature 1 describes an optical filter including a transparent dielectric substrate and a light-absorbing layer including a light absorber formed by a phosphonic acid having a phenyl group or a halogenated phenyl group and copper ion. Patent Literature 1 also describes a light-absorbing composition for forming the light-absorbing layer. An organic solvent such as toluene is used in preparation of the light-absorbing composition to prevent aggregation of the light absorber. CITATION LIST Patent Literature Patent Literature 1: JP 6339755 B1 SUMMARY OF INVENTION Technical Problem The technique described in Patent Literature 1 leaves room for reducing the content of a low-polarity organic solvent such as toluene in the light-absorbing composition. Therefore, the present invention provides a liquid composition for optical filters, the liquid composition containing a given light absorber and being capable of decreasing the content of a low-polarity organic solvent. Solution to Problem The present invention provides a liquid composition for optical filters, containing: a light absorber formed by a phosphonic acid having an aryl group bonded to a phosphorus atom and copper ion;at least one of an alkoxysilane and a hydrolysate of an alkoxysilane;a phosphoric acid ester; anda solvent, whereina content of an organic solvent having a relative permittivity of 7 or less at 20° C. is 50 mass % or less. Advantageous Effects of Invention The above liquid composition contains the given light absorber and is capable of reducing the content of a low-polarity solvent. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows a transmittance spectrum of a liquid composition 1. FIG. 2A shows a transmittance spectrum of a resin containing liquid composition 1-1. FIG. 2B shows a transmittance spectrum of a resin-containing liquid composition 1-2. FIG. 3A shows a transmittance spectrum of an optical filter according to Example 1. FIG. 3B shows a transmittance spectrum of an optical filter according to Example 2. FIG. 4 shows a transmittance spectrum of a liquid composition 6. FIG. 5 shows a transmittance spectrum of a liquid composition 8. FIG. 6A shows a transmittance spectrum of a resin-containing liquid composition 6-1. FIG. 6B shows a transmittance spectrum of a resin-containing liquid composition 6-2. FIG. 7 shows a transmittance spectrum of a resin-containing liquid composition 8-1. FIG. 8 shows a transmittance spectrum of an optical filter according to Example 11. FIG. 9 shows a transmittance spectrum of an optical filter according to Example 12. FIG. 10 shows a transmittance spectrum of an optical filter according to Example 15. FIG. 11 shows a transmittance spectrum of a liquid composition 9. FIG. 12 shows a transmittance spectrum of a resin-containing liquid composition 9-1. FIG. 13 shows a transmittance spectrum of an optical filter according to Example 16. FIG. 14 shows a transmittance spectrum of a liquid composition 10. FIG. 15 shows a transmittance spectrum of a resin-containing liquid composition 10-1. FIG. 16 shows a transmittance spectrum of an optical filter according to Example 17. FIG. 17 shows a transmittance spectrum of a resin-containing liquid composition 10-2. FIG. 18 shows a transmittance spectrum of an optical filter according to Example 18. FIG. 19 sh