Light absorber, light-absorbing compound, dispersion liquid of light-absorbing compound, light-absorbing composition, optical filter, photoelectric conversion element, ambient light sensor, and imaging device

Abstract

The light absorber (10) has a transmission spectrum satisfying the following conditions (I), (II), (III), (IV), and (V) at an incidence angle of 0 DEG. The light absorber 10 has a haze of less than 0.20%. (I) The average value TA0deg (460-600) is 75% or more. (II) The short wavelength-side cutoff wavelength [lambda] H0deg (S) is from 390 nm to 450 nm. (III) The cutoff wavelength [lambda] H0deg (L) on the long wavelength side is 600 nm to 680 nm. (IV) The average value TA0deg (300-380) is 1.2% or less. (V) The average value TA0deg (750-1000) is 1.2% or less.

Description

Technical Field

[0001] The present invention relates to a light absorber, a light absorbing compound, a dispersion of a light absorbing compound, a light absorbing composition, an optical filter, a photoelectric conversion element, an ambient light sensor and an imaging device. Background Art

[0002] In an imaging device or an ambient light sensor using a solid-state imaging element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), various filters are arranged in front of the solid-state imaging element. For example, in an imaging device, a filter can be used to obtain an image with good color reproducibility. In an ambient light sensor, a filter can be used to adjust the sensing of ambient light.

[0003] Generally speaking, solid-state imaging elements have sensitivity in a wide wavelength range from the ultraviolet region to the infrared region. On the other hand, human visual sensitivity only exists in the so-called visible light region of about 380nm to 780nm. Therefore, in order to make the spectral sensitivity of the solid-state imaging element in the imaging device close to the visual sensitivity of humans, it is known to configure a filter in front of the solid-state imaging element to block part of the infrared or ultraviolet light.

[0004] Among them, light-absorbing filters having a film or layer containing a light absorber have attracted attention. The transmittance characteristics of the filter having a film containing a light absorber are not easily affected by the incident angle. Therefore, for example, in an imaging device, even when light is incident on the filter at an angle, a good image with little change in color tone, little color unevenness within the surface, and good reproducibility can be obtained. In addition, the light-absorbing filter does not use a light-reflecting film, so it is possible to suppress the generation of ghosting or light spots caused by multiple reflections caused by light reflection, and it is easy to obtain a good image. In addition, the filter having a film containing a light absorber is also advantageous from the perspective of miniaturization and thinning of the imaging device.

[0005] For example, Patent Document 1 describes an optical filter including a UV-IR absorbing layer. The UV-IR absorbing layer includes a UV-IR absorber formed of phosphonic acid and copper ions that can absorb ultraviolet rays and infrared rays. It is also described that the haze of the UV-IR absorbing layer is 5% or less. The haze of the UV-IR absorbing layer is 5% or less. For example, by assembling an optical filter including such a UV-IR absorbing layer into an imaging device, a high-quality image can be obtained.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 6606626 Summary of the invention

[0009] Problems to be solved by the invention

[0010] The technology described in Patent Document 1 has room for further study from the perspective of improving the performance of an optical filter. Therefore, the present invention provides a light absorber that is advantageous from the perspective of improving the performance of an optical filter.

[0011] Means for solving problems

[0012] The present invention provides a light absorber having a transmission spectrum satisfying the following conditions (I), (II), (III), (IV) and (V) at an incident angle of 0°,

[0013] Has a haze of less than 0.20%.

[0014] (I) The average value of the transmittance in the wavelength range of 460 nm to 600 nm is 75% or more.

[0015] (II) The short-wavelength-side cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 350 nm to 450 nm is 390 nm to 450 nm.

[0016] (III) The long-wavelength side cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 600 nm to 700 nm is 600 nm to 680 nm.

[0017] (IV) The average value of the transmittance in the wavelength range of 300 nm to 380 nm is 1.2% or less.

[0018] (V) The average value of the transmittance in the wavelength range of 750 nm to 1100 nm is 1.2% or less.

[0019] In addition, the present invention provides a light absorbing compound comprising:

[0020] a first light absorbing compound comprising a copper component and a first phosphonic acid represented by the following formula (a); and

[0021] The second light absorbing compound comprises a copper component and a second phosphonic acid represented by the following formula (b),

[0022] In the following formula (a), R 1 is an alkyl group or a haloalkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom,

[0023] In the following formula (b), R 2is an aryl group or a modified aryl group in which at least one hydrogen atom in the aryl group is substituted with a halogen atom, a nitro group or a hydroxyl group,

[0024] The transmission spectrum of the dispersion of the light absorbing compound satisfies the following conditions (i), (ii), (iii) and (iv).

[0025] (i) The average value of the transmittance in the wavelength range of 460 nm to 600 nm is 85% or more.

[0026] (ii) The short-wavelength-side cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 350 nm to 450 nm is 380 nm to 420 nm.

[0027] (iii) The long-wavelength side cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 600 nm to 700 nm is 600 nm to 650 nm.

[0028] (iv) The average transmittance in the wavelength range of 725 nm to 1000 nm is 5% to 20%.

[0029] [Chemistry 1]

[0030]

[0031] In addition, the present invention provides a dispersion of a light absorbing compound, characterized in that it comprises:

[0032] Light absorbing compounds;

[0033] Solvents; and

[0034] Alkoxysilane or a hydrolyzate of alkoxysilane,

[0035] The light absorbing compound comprises: a first light absorbing compound comprising a copper component and a first phosphonic acid represented by the following formula (a); and a second light absorbing compound comprising a copper component and a second phosphonic acid represented by the following formula (b),

[0036] In the following formula (a), R 1 is an alkyl group or a haloalkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom,

[0037] In the following formula (b), R 2 It is an aryl group or a modified aryl group in which at least one hydrogen atom in the aryl group is substituted with a halogen atom, a nitro group or a hydroxyl group.

[0038] [Chemistry 2]

[0039]

[0040] In addition, the present invention provides a light-absorbing composition comprising:

[0041] A first light absorbing compound comprising a copper component and a first phosphonic acid represented by the following formula (a);

[0042] a second light absorbing compound comprising a copper component and a second phosphonic acid represented by the following formula (b);

[0043] Solvents; and

[0044] Binder,

[0045] In the following formula (a), R 1 is an alkyl group or a haloalkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom,

[0046] In the following formula (b), R 2 is an aryl group or a modified aryl group in which at least one hydrogen atom in the aryl group is substituted with a halogen atom, a nitro group or a hydroxyl group,

[0047] The ratio of the content of the second phosphonic acid to the content of the first phosphonic acid is 1.8 to 9 on an amount basis.

[0048] [Chemistry 3]

[0049]

[0050] Furthermore, the present invention provides an optical filter including the above-mentioned light absorber.

[0051] In addition, the present invention provides a photoelectric conversion element comprising a light receiving surface and the above-mentioned light absorber.

[0052] The light receiving surface and the light absorber are arranged in this order.

[0053] In addition, the present invention provides an ambient light sensor including the above-mentioned optical filter.

[0054] Furthermore, the present invention provides an imaging device including the above-mentioned optical filter.

[0055] Effects of the Invention

[0056] The above-mentioned light absorber is advantageous in terms of improving the performance of the optical filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1A This is a cross-sectional view showing an example of the optical filter of the present invention.

[0058] Figure 1B This is a cross-sectional view showing another example of the optical filter of the present invention.

[0059] Figure 1C This is a cross-sectional view showing still another example of the optical filter of the present invention.

[0060] Figure 1D This is a cross-sectional view showing still another example of the optical filter of the present invention.

[0061] Figure 1E This is a cross-sectional view showing still another example of the optical filter of the present invention.

[0062] Figure 1F This is a cross-sectional view showing still another example of the optical filter of the present invention.

[0063] Figure 2A It is a cross-sectional view showing an example of the ambient light sensor of the present invention.

[0064] Figure 2B This is a cross-sectional view showing an example of the photoelectric conversion element of the present invention.

[0065] Figure 3A This is a diagram showing an example of an imaging device according to the present invention.

[0066] Figure 3B This is a diagram showing another example of the imaging device of the present invention.

[0067] Figure 4 It is shown Figure 1B A graph showing an example of a transmission spectrum of the substrate shown.

[0068] Figure 5A Graph showing the transmission spectrum of the light absorber of Example 1 at each incident angle.

[0069] Figure 5B Graph showing the reflection spectrum of the light absorber of Example 1 at each incident angle.

[0070] Figure 5C Graph showing the transmission spectrum of the dispersion liquid of the light absorbing compound of Example 1.

[0071] Figure 6 This is a graph showing the transmission spectrum of the light absorber of Example 2 at each incident angle.

[0072] Figure 7 Graph showing the transmission spectrum of the light absorber of Example 3 at each incident angle.

[0073] Fig. 8A Graph showing the transmission spectrum of the light absorber of Example 4 at each incident angle.

[0074] Figure 8B Graph showing the transmission spectrum of the dispersion liquid of the light absorbing compound of Example 4.

[0075] Fig.9AGraph showing the transmission spectrum of the light absorber of Example 5 at each incident angle.

[0076] Fig. 9B It is a graph showing the reflection spectrum of the light absorber of Example 5 at each incident angle.

[0077] Fig. 9C Graph showing the transmission spectrum of the dispersion liquid of the light absorbing compound of Example 5.

[0078] Fig.10 Graph showing the transmission spectrum of the light absorber of Example 6 at each incident angle.

[0079] Fig.11 Graph showing the transmission spectrum of the light absorber of Example 7 at each incident angle.

[0080] Fig. 12A Graph showing the transmission spectrum of the light absorber of Example 8 at each incident angle.

[0081] Fig. 12B It is a graph showing the reflection spectrum of the light absorber of Example 8 at each incident angle.

[0082] Fig. 12C This is a graph showing the transmission spectrum of the dispersion liquid of the light absorbing compound of Example 8.

[0083] Fig.13 Graph showing the reflection spectrum of the light absorber of Example 9 at each incident angle.

[0084] Fig.14A : is a graph showing the transmission spectrum of the light absorber of Example 10 at an incident angle of 0°.

[0085] Fig. 14B Graph showing the transmission spectrum of the dispersion liquid of the light absorbing compound of Example 10.

[0086] Fig.15 : is a graph showing the transmission spectrum of the light absorber of Example 11 at an incident angle of 0°.

[0087] Fig.16 : is a graph showing the transmission spectrum of the light absorber of Example 12 at an incident angle of 0°.

[0088] Fig.17A This is a graph showing the transmission spectrum of the optical filter of Example 13 at each incident angle.

[0089] Fig. 17B This is a graph showing the reflection spectrum of the optical filter of Example 13 at each incident angle.

[0090] Fig.18 : is a graph showing the transmission spectrum of the light absorber of Comparative Example 1 at an incident angle of 0°.

[0091] Fig.19 : is a graph showing the transmission spectrum of the light absorber of Comparative Example 2 at an incident angle of 0°.

[0092] Fig. 20A : is a graph showing the transmission spectrum of the light absorber of Reference Example 1 at an incident angle of 0°.

[0093] Fig. 20B Graphs showing the transmission spectrum of the light absorber of Reference Example 1 at an incident angle of 0° and the rate of change of transmittance with respect to wavelength.

[0094] Fig.21A : is a graph showing the transmission spectrum of the light absorber of Reference Example 1 at an incident angle of 0°.

[0095] Fig.21B Graphs showing the transmission spectrum of the light absorber of Reference Example 1 at an incident angle of 0° and the rate of change of transmittance with respect to wavelength. DETAILED DESCRIPTION

[0096] Due to the global popularity of information terminals such as smartphones equipped with camera modules, the requirements for the quality and performance of images obtained by cameras are increasing. Therefore, there is a strong demand for high performance of filters assembled in imaging devices or camera modules. In particular, in filters that shield ultraviolet rays and infrared rays, the specifications for their transmission spectra have become strict and detailed, and there is also a high demand for minimizing their haze.

[0097] Patent Document 1 describes the content of copper ions contained in a composition for forming a UV-IR absorbing layer, and also describes the preferred range of viscosity of a liquid composition as a precursor of the UV-IR absorbing layer. On the other hand, the haze value of the UV-IR absorbing layer described in Patent Document 1 is at least 0.2%. If a light absorber that can achieve a smaller haze while shielding ultraviolet rays and infrared rays can be provided, for example, the performance of an optical filter can be further improved. The inventors have conducted repeated and in-depth research, and finally found a light absorber that can achieve both a smaller haze and a prescribed transmission characteristic that can shield ultraviolet rays and infrared rays.

[0098] Hereinafter, embodiments of the present invention will be described. It should be noted that the following description is for illustration of the present invention, and the present invention is not limited to the following embodiments.

[0099] Figure 1Ais a cross-sectional view showing the optical filter 1a. Figure 1A As shown, the optical filter 1a includes a light absorber 10. The light absorber 10 has a transmission spectrum satisfying the following conditions (I), (II), (III), (IV), and (V) at an incident angle of 0°. In addition, the light absorber 10 has a haze of less than 0.20%.

[0100] (I) Average value T of transmittance in the wavelength range of 460 nm to 600 nm A 0deg(460-600) More than 75%.

[0101] (II) Short-wavelength side cutoff wavelength λ at which the transmittance reaches 50% in the wavelength range of 350 nm to 450 nm H 0deg(S) It is 390nm~450nm.

[0102] (III) Long-wavelength side cutoff wavelength λ at which the transmittance reaches 50% in the wavelength range of 600 nm to 700 nm H 0deg(L) It is 600nm~680nm.

[0103] (IV) Average value T of transmittance in the wavelength range of 300 nm to 380 nm A 0deg(300-380) It is less than 1.2%.

[0104] (V) Average value T of transmittance in the wavelength range of 750nm to 1100nm A 0deg(750-1000) It is less than 1.2%.

[0105] In the light absorber 10, by satisfying the conditions (I), (II) and (III), the transmittance in the visible light region is likely to be increased, and in particular, by satisfying the condition (III), the transmittance in the red band of the light absorber is likely to be increased. In addition, by satisfying the condition (V), the light absorber 10 can well shield infrared rays.

[0106] like Figure 1A As shown in FIG. 1 , the light absorber 10 can be used alone as the filter 1a. The light absorber 10 can also be in the form of a film or thin film that absorbs part of the light. In addition, it can also be in the form of a part of a layer of a functional film that also has other functions. The filter 1a can also be as shown in FIG. Figure 1BThe optical filter 1b is configured as shown in FIG. In addition to the light absorber 10, the optical filter 1b further includes a substrate 20. The light absorber 10 can be formed to cover at least a portion of the surface of the substrate 20. The substrate 20 includes, for example, resin, glass, and metal. An example of the substrate 20 is D263T eco from Corning. D263T eco with a thickness of 3 mm has a Figure 4 The transmission spectrum is shown. Figure 4 In the transmission spectrum shown, the transmittance in the wavelength range of 360 nm to 2300 nm is 90% or more, and the transmittance in the wavelength range of 335 nm to 2500 nm is 85% or more.

[0107] The transmission spectrum is determined, for example, by causing light with a wavelength of 300 nm to 1200 nm to be incident on a predetermined object at a predetermined incident angle (IA) and measuring the transmitted light using a spectrophotometer or the like. The reflection spectrum is determined by causing light with a wavelength of 300 nm to 1200 nm to be incident on a predetermined object at a predetermined incident angle and measuring the reflected light using a spectrophotometer or the like.

[0108] The light absorber 10 alone may satisfy the conditions regarding the transmission spectrum, or an optical filter including the substrate and the light absorber 10 may satisfy the conditions regarding the transmission spectrum. In other words, the optical filter including the substrate and the light absorber 10 may satisfy the above-mentioned conditions (I), (II), (III), (IV), and (V) at an incident angle of 0°, or the light absorber 10 may satisfy the conditions regarding the transmission spectrum described below.

[0109] It should be noted that, in this specification, unless otherwise specified, the visible light region or the visible light region is a wavelength range of 380nm to 780nm, and the red band is defined as a wavelength range of 580nm to 780nm or a portion of the band within the range. In addition, unless otherwise specified, infrared light is defined as light (electromagnetic waves) with a wavelength greater than 780nm, the upper limit of the visible light region, and a range of 1400nm, corresponding to near infrared light (NIR). Ultraviolet light is defined as light (electromagnetic waves) ranging from a wavelength of 280nm to 380nm, the lower limit of the visible light region, corresponding to a portion of UV-A and UV-B.

[0110] The optical filter assembled into the ambient light sensor and the camera device is of course required to have an appropriate transmission spectrum and reflection spectrum. On the other hand, for example, even in the case where the transmittance in the visible light region is high, if the haze is large, part of the light incident on the filter or the light absorber is scattered or diffused inside it, which may cause turbidity and opacity. This may affect the formation of a clear image. On the other hand, the light absorber 10 satisfies the above-mentioned conditions (I), (II), (III), (IV) and (V) and has a haze of less than 0.20%, so it has a desired transmission spectrum and the transparency of the filter is easily improved. Therefore, from the perspective of improving the image quality of the image obtained by the camera device, the light absorber 10 is suitable. In addition, the light absorber 10 can easily improve the sensing accuracy of ambient light in the ambient light sensor.

[0111] The haze value of the light absorber 10 can be determined by measuring the light absorber 10 alone, or by measuring an optical filter in which the light absorber 10 is provided on a substrate such as glass or resin.

[0112] The haze of the light absorber 10 may be 0.19% or less, preferably 0.18% or less, and more preferably 0.15% or less.

[0113] Regarding the condition (I) above, the average value T A 0deg(460-600) Preferably, it is 80% or more, and more preferably 85% or more. In addition, in the transmission spectrum of the light absorber 10 in the wavelength range of 300nm to 1100nm at an incident angle of 0°, the wavelength corresponding to the maximum transmittance may be in the range of 500nm to 600nm. In this case, in the human visual sensitivity spectrum (visual sensitivity curve), the area with the highest visual sensitivity is in the range of 500nm to 600nm, so it can be expected to obtain an image that appears brighter.

[0114] Regarding the condition (II) above, the short-wavelength side cutoff wavelength λ H 0deg(S) It is preferably 400 nm to 450 nm, may be 400 nm to 440 nm, may be 400 nm to 430 nm, or may be 400 nm to 420 nm.

[0115] Regarding the condition (III) above, the long wavelength side cutoff wavelength λ H 0deg(L) It is preferably 610 nm to 680 nm, and more preferably 620 nm to 680 nm. Long wavelength side cutoff wavelength λ H 0deg(L) It may be 620nm to 670nm, or 620nm to 660nm.

[0116] Regarding the above condition (IV), the average value T A 0deg(300-380) It is preferably 1% or less, and more preferably 0.5% or less.

[0117] Regarding the above condition (V), the average value T A 0deg(750-1000) It is preferably 1% or less, and more preferably 0.5% or less.

[0118] The light absorber 10 may have a reflection spectrum satisfying the following conditions (VI) and (VII) at an incident angle of 5°, for example.

[0119] (VI) Maximum value R of reflectivity in the wavelength range of 300 nm to 400 nm M 5deg(300-400) It is less than 7.5%.

[0120] (VII) Maximum value R of reflectivity in the wavelength range of 700 nm to 1200 nm M 5deg(700-1200) It is less than 7.5%.

[0121] By satisfying the above conditions (VI) and (VII), when the optical filter having the light absorber 10 is assembled into an imaging device, it is possible to suppress a portion of the light reflected from the optical filter from being reflected on the surface of the housing, frame, or aperture and lens of the optical system constituting the imaging device, or a portion of the reflected light from being incident on the imaging element while projecting the aperture and its shape. Therefore, it is possible to suppress harmful light such as ghosting and flare that does not contribute to image formation from being incident on the imaging element. In addition, this characteristic achieves its purpose only through the action and function of the light absorber 10, without using a light reflection film formed by a dielectric multilayer film or the like in the optical filter that plays the role of shielding a portion of light.

[0122] Regarding the condition (VI) above, the maximum value R M 5deg(300-400) It is preferably 7.0% or less, more preferably 6.5% or less, and even more preferably 6% or less.

[0123] Regarding the condition (VII) above, the maximum value R M 5deg(700-1200) It is preferably 7.0% or less, more preferably 6.5% or less, and even more preferably 6% or less.

[0124] The light absorber 10 may have a transmission spectrum satisfying the following conditions (1-i), (1-ii), (1-iii) and (1-iv) at incident angles of, for example, 0°, 40°, 50°, 60° and 70°. H 40deg(S) , H50deg(S) , H 60deg(S) and λ H 70deg(S) These are short-wavelength-side cutoff wavelengths at which the transmittance reaches 50% in the wavelength range of 350 nm to 450 nm at incident angles of 40°, 50°, 60°, and 70°, respectively.

[0125] (1-i)λ H 40deg(S) -λ H 0deg(S) ≤2.5nm

[0126] (1-ii)λ H 50deg(S) -λ H 0deg(S) ≤4.5nm

[0127] (1-iii)λ H 60deg(S) -λ H 0deg(S) ≤7.5nm

[0128] (1-iv)λ H 70deg(S) -λ H 0deg(S) ≤20nm

[0129] The light absorber 10 may have a transmission spectrum satisfying the following conditions (2-i), (2-ii), (2-iii) and (2-iv) at incident angles of, for example, 0°, 40°, 50°, 60° and 70°. H 40deg(L) , H 50deg(L) , H 60deg(L) and λ H 70deg(L) These are long-wavelength-side cutoff wavelengths at which the transmittance reaches 50% in the wavelength range of 600 nm to 700 nm at incident angles of 40°, 50°, 60°, and 70°, respectively.

[0130] (2-i)λ H 0deg(L) -λ H 40deg(L) ≤4nm

[0131] (2-ii)λ H 0deg(L) -λ H 50deg(L) ≤7nm

[0132] (2-iii)λH 0deg(L) -λ H 60deg(L) ≤12nm

[0133] (2-iv)λ H 0deg(L) -λ H 70deg(L) ≤30nm

[0134] By satisfying the conditions (1-i) to (1-iv) and (2-i) to (2-iv), when the optical filter including the light absorber 10 is incorporated into an imaging device, a difference in color tone is unlikely to occur between a region where light incident on the optical filter at a small incident angle contributes to image formation and a region where light incident on the optical filter at a large incident angle contributes to image formation. Specifically, a difference in color tone is unlikely to occur between the central portion and the peripheral portion of the acquired image, and a difference in color tone is unlikely to occur in an image acquired by an imaging device having a wide-angle lens or an ultra-wide-angle lens.

[0135] The light absorber 10 typically contains a predetermined light absorber. The light absorber contained in the light absorber is not limited to a specific substance as long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the above conditions (I) to (V) and the light absorber 10 has a haze of less than 0.20%.

[0136] The light absorber 10 can be produced, for example, by curing a liquid light absorbing composition. The light absorber 10 may be a film or a film formed on a predetermined object such as glass or resin, and may exist in a solid state.

[0137] The light-absorbing composition includes a light-absorbing compound and a binder. A dispersion of the light-absorbing compound can be used in the preparation of the light-absorbing composition. In the light absorber 10, a compound or its precursor that brings a specified transmission spectrum, reflection spectrum, or low haze value can of course also be included in the light-absorbing composition as a precursor of the light absorber 10 and the dispersion in which the light-absorbing compound contained in the light-absorbing composition is dispersed. Hereinafter, the dispersion of the light-absorbing compound is also referred to as a light-absorbing dispersion. The light-absorbing dispersion contains a light-absorbing compound like the light-absorbing composition, but is different in that it does not contain a compound that is cured by heating or irradiation with electromagnetic waves such as light. Resin curing means that a part of the functional groups reacts and polymerizes by heating, placement, and irradiation with electromagnetic waves such as light, and the polymer structure is formed and cured, and it cannot be restored.

[0138] The light-absorbing composition, for example, comprises a light-absorbing compound, a solvent and a binder. The light-absorbing composition may further comprise a dispersant as required. The dispersant helps disperse the light-absorbing compound in the solvent. The light-absorbing composition may be a precursor of a light absorber and has curability that can be cured by heating or irradiation with electromagnetic waves. In addition, the light-absorbing composition is not limited to a specific composition as long as it satisfies the above conditions (I) to (V) when cured to become a light absorber. The haze of the light absorber is preferably less than 0.20%.

[0139] The light absorbing compound can be, for example, a compound containing phosphonic acid and copper, a compound containing phosphate ester and copper, a compound containing phosphoric acid and copper, or a compound containing M n Cu y PO 4-z (M is a metal element other than Cu) represented by a phosphate-copper complex, a compound containing a sulfonic acid and a copper component, a compound containing an oxide of tungsten, a metal oxide such as ITO and ATO, or a known organic pigment compound. Examples of organic pigment compounds are diimmonium compounds, cyanine compounds, squarylium salt compounds, phthalocyanine compounds, and pyrrolopyrrole compounds. For example, the light absorber 10 may contain a light absorbing compound containing a phosphonic acid and a copper component as a light absorber, and may contain an ultraviolet absorber that absorbs at least a portion of ultraviolet rays.

[0140] Among them, compounds containing phosphonic acid and copper components, compounds containing phosphate esters and copper components, compounds containing phosphoric acid and copper components, compounds containing sulfonic acid and copper components, and substances in which each compound forms a complex, which have a wide absorption band in the infrared region, are advantageous as light absorbers. This is because the shielding of light in a specified wavelength range can be achieved only by the effect of light absorption in the light absorber 10. In the light absorber 10, these compounds can be used alone or in combination. In addition, phosphonic acid, phosphate esters and phosphoric acid are oxides containing phosphorus (P), and they can coexist. For example, in the light absorber 10, a compound containing phosphonic acid, phosphate esters and copper components may exist. As a light absorber, even in the case of obtaining a complex containing phosphonic acid and copper components, a phosphate ester may be added as a dispersant. In this case, the light absorber 10 may also contain a compound containing phosphonic acid, phosphate esters and copper components.

[0141] As long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the conditions (I) to (V) and the light absorber 10 has a haze of less than 0.20%, the phosphonic acid in the light absorbing compound is not limited to a specific phosphonic acid. The phosphonic acid includes, for example, a first phosphonic acid represented by the following formula (a). In formula (a), R 1It is an alkyl group or a halogenated alkyl group in which at least one hydrogen atom in the alkyl group is replaced by a halogen atom. In this case, the transmission band of the light absorber 10 is likely to reach a wavelength near 700 nm, and the light absorber 10 is likely to have the desired transmittance characteristics. Phosphonic acids having these groups are collectively referred to as alkylphosphonic acids. The phosphonic acid in the light absorbing compound includes, for example, a second phosphonic acid represented by the following formula (b). In formula (b), R 2 It is an aryl group or a modified aryl group in which at least one hydrogen atom in the aryl group is replaced by a halogen atom, a nitro group or a hydroxyl group. As a result, the optical filter 1a is more likely to have the desired transmittance characteristics. Phosphonic acids having these groups are collectively referred to as arylphosphonic acids. The modified aryl group is, for example, a halogenated phenyl group.

[0142] [Chemistry 4]

[0143]

[0144] The first phosphonic acid is, for example, methylphosphonic acid, ethylphosphonic acid, n-(n-)propylphosphonic acid, isopropylphosphonic acid, n-(n-)butylphosphonic acid, isobutylphosphonic acid, sec-butylphosphonic acid, tert-butylphosphonic acid or bromomethylphosphonic acid.

[0145] The second phosphonic acid is, for example, phenylphosphonic acid, bromophenylphosphonic acid, benzylphosphonic acid, fluorophenylphosphonic acid, iodophenylphosphonic acid, nitrophenylphosphonic acid, hydroxyphenylphosphonic acid, tolylphosphonic acid, xylylphosphonic acid, or naphthylphosphonic acid.

[0146] The light absorber 10, the light absorbing composition, and the light absorbing dispersion may contain one or more phosphonic acids selected from the above-mentioned phosphonic acids.

[0147] The phosphonic acid contained in the light absorber 10, the light absorbing composition, and the light absorbing dispersion may include a first phosphonic acid and a second phosphonic acid. In this case, the phosphonic acid may include one or more first phosphonic acids, and may also include one or more second phosphonic acids. In the light absorber 10, the light absorbing composition, and the light absorbing dispersion, a first light absorbing compound and a second light absorbing compound may exist. The first light absorbing compound includes a copper component and a first phosphonic acid. The second light absorbing compound includes a copper component and a second phosphonic acid.

[0148] In the light absorber 10, the light absorbing composition and the light absorbing dispersion, the ratio α of the content of the second phosphonic acid to the content of the first phosphonic acid is ar / ak Not limited to a specific value. ar / ak For example, the ratio α is 1.8 to 9. In the preparation of the light absorbing composition or light absorbing dispersion, if a part of the compound aggregates and settles, the haze of the light absorbing body becomes high, and the light absorbing body is difficult to be suitable for the imaging device. ar / ak9 or less, in the preparation of the light absorbing composition or light absorbing dispersion, it is possible to prevent a part of the compounds from agglomerating and settling. Therefore, the haze of the light absorber 10 is easily less than 0.20%. In addition, by making the ratio α ar / ak When the ratio is 1.8 or more, it is possible to prevent the short-wavelength side cutoff wavelength from being shorter than a predetermined range and the long-wavelength side cutoff wavelength from being longer than a predetermined range. As a result, the transmittance in the visible light region of the light absorber 10 is likely to be high.

[0149] By making the ratio α ar / ak When the maximum value dT / dλ of the rate of change of transmittance with respect to wavelength dT / dλ [% / nm] is 1.8 or more, it is easy to prevent at least one step from being observed in the curve of the transmission spectrum in the wavelength range of 420nm to 480nm in the transmission spectrum of the light absorber or the optical filter. max and the minimum value dT / dλ min The difference is 0.2 [% / nm] or more, or the minimum value of the change rate of transmittance with respect to wavelength dT / dλ min When the value of dT / dλ is less than 0.2 [% / nm], such a step can be significantly appeared. In dT / dλ, T is the transmittance [%] and λ is the wavelength [nm]. The appearance of such a step may have an adverse effect when the light absorber or filter is applied to a camera device or an ambient light sensor.

[0150] Ratio α ar / ak It is preferably 2 or more, more preferably 3 or more, further preferably 4 or more, particularly preferably 5.5 or more, and particularly preferably 6.0 or more. ar / ak It is preferably 8.5 or less, more preferably 8.0 or less, and further preferably 7.5 or less.

[0151] In the light absorber 10, the light absorbing composition and the light absorbing dispersion, the copper component is a concept including copper ions, copper complexes and compounds containing copper. The copper component can have a preferred absorption characteristic for a part of light belonging to the near-infrared region and a high transmittance of light in the wavelength range included in the visible light region of wavelengths 450nm to 680nm. Specifically, through the electron transition in the d orbit of the divalent copper ion, the light of the wavelength belonging to the near-infrared region corresponding to the energy is selectively absorbed, thereby exerting excellent near-infrared absorption characteristics. In particular, the copper component containing the divalent copper ion can be supplied in the form of a copper salt and mixed with phosphonic acid, and the phosphonic acid is coordinated to the copper component containing the copper ion to form a copper complex (copper salt).

[0152] The supply source of the copper component for phosphonic acid coordination is not limited thereto, and may be anhydrous or hydrated copper salts of organic acids such as copper acetate, copper benzoate, copper pyrophosphate, and copper stearate, or mixtures thereof. These copper salts may be used alone, or a plurality of copper salts or a mixture of a plurality of copper salts may be used.

[0153] In the light absorber 10, the light absorbing composition and the light absorbing dispersion, the ratio of the content of the phosphonic acid to the content of the copper component is α PC Not limited to a specific value. PC For example, the ratio is 0.3 to 3 based on the amount of substance. When both the first phosphonic acid and the second phosphonic acid are contained, the ratio α PC It can be the ratio of the sum of the content of the first phosphonic acid and the content of the second phosphonic acid to the content of the copper component. PC When the ratio is in the range of 0.3 to 3, each element or group easily constitutes the light absorber in an appropriate amount, thereby preventing oxidation from occurring in the light absorber 10, the light absorbing composition, and the light absorbing dispersion, and thus easily exhibiting good weather resistance.

[0154] Ratio α PC The amount is preferably 0.4 to 2, more preferably 0.6 to 1.2.

[0155] When both the first phosphonic acid and the second phosphonic acid are contained in the light absorber 10, the light absorbing composition, and the light absorbing dispersion, the ratio α ak / c and ratio α ar / c Each is not limited to a specific value. ak / c is the ratio of the first phosphonic acid content to the copper content, and the ratio α ar / c It is the ratio of the content of the second phosphonic acid to the content of the copper component. ak / c For example, it is 0.05 to 0.8 based on the amount of substance. ak / c It is preferably 0.1 to 0.4, and more preferably 0.1 to 0.3. ar / c For example, it is 0.2 to 1.5, preferably 0.4 to 1.2, and more preferably 0.5 to 1 on an amount basis.

[0156] The light absorber 10, the light absorbing composition and the light absorbing dispersion may further contain a phosphate compound. Through the action of the phosphate, the light absorbing compound (light absorber) is easily and appropriately dispersed in the light absorber 10, the light absorbing composition and the light absorbing dispersion. The phosphate can function as a dispersant for the light absorbing compound, and a part of it can also react with the metal component to form a light absorbing compound. For example, the phosphate can be coordinated to the light absorbing compound, or can react with another part of the compound, or can form a part of the complex with the copper component. As long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the conditions (I) to (V), the compound containing the phosphate and the copper component can also absorb light of a part of the wavelength. As long as the light absorbing compound containing at least phosphonic acid and copper components is appropriately dispersed in the light absorbing composition or the light absorbing dispersion as a precursor of the light absorber, the phosphate may be substantially not contained, or may be completely not contained. For example, when the alkoxysilane monomer described later is contained in the light absorbing composition as a dispersant, the amount of phosphate added can be reduced.

[0157] Phosphate ester is not limited to a specific phosphate ester or its compound. Phosphate ester has, for example, a polyoxyalkyl group. Examples of such phosphate ester include Plysurf A208N: polyoxyethylene alkyl (C12, C13) ether phosphate, Plysurf A208F: polyoxyethylene alkyl (C8) ether phosphate, Plysurf A208B: polyoxyethylene lauryl ether phosphate, Plysurf A219B: polyoxyethylene lauryl ether phosphate, Plysurf AL: polyoxyethylene styrenated phenyl ether phosphate, Plysurf A212C: polyoxyethylene tridecyl ether phosphate, or Plysurf A215C: polyoxyethylene tridecyl ether phosphate. All of them are products manufactured by Daiichi Kogyo Seiyaku Co., Ltd. In addition, examples of phosphate ester include NIKKOL DDP-2: polyoxyethylene alkyl ether phosphate, NIKKOL DDP-4: polyoxyethylene alkyl ether phosphate, or NIKKOLDDP-6: polyoxyethylene alkyl ether phosphate. These are all products manufactured by Nikkol Chemicals Co., Ltd. These phosphoric acid ester compounds may be used alone or in combination of two or more.

[0158] In the light absorber 10, the light absorbing composition and the light absorbing dispersion, the ratio of the content of the phosphonic acid to the content of the phosphate ester is β p / es It is not limited to a specific value. p / esFor example, it is 1 to 3 on a mass basis. Thus, even if the light absorber 10 comes into contact with water vapor or moisture, hydrolysis of the phosphate ester can be suppressed, and the light absorber 10 is likely to have good weather resistance. The ratio of the content of phosphonic acid to the content of the phosphate ester in the light absorber 10 is preferably 1.2 to 3.8, more preferably 1.5 to 2.5.

[0159] The light absorber 10, the light absorbing composition and the light absorbing dispersion may further contain, for example, alkoxysilane or a hydrolyzate of alkoxysilane. Alkoxysilane includes a monomer of alkoxysilane, a substance formed by hydrolysis of a part of the monomer of alkoxysilane, and a substance in the form of a dimer or a polymer by polymerization of at least a part of the hydrolyzate of alkoxysilane. The presence of alkoxysilane can prevent the particles of the light absorber from agglomerating with each other, so even if the content of the phosphate ester is reduced, the light absorber is easily and well dispersed in the light absorbing composition or the light absorber formed by curing thereof. In addition, for example, in the case of using a light absorbing composition to manufacture a light absorber or an optical filter, by treating the alkoxysilane monomer in a manner that the hydrolysis reaction and the polycondensation reaction fully occur, a siloxane bond (-Si-O-Si-) is formed, and the light absorber has good moisture resistance. In addition, the light absorber has good heat resistance. The reason is that the bond energy of the siloxane bond is higher than that of the -CC- bond and the -CO- bond, and it is chemically stable and has excellent heat resistance and moisture resistance.

[0160] When the light-absorbing composition contains alkoxysilane, when the light-absorbing composition is cured to produce a light absorber, a so-called humidification treatment of exposing the composition to a high humidity atmosphere for a certain period of time may be performed. It is believed that the water component in the atmosphere promotes the hydrolysis of the alkoxysilane contained in the light-absorbing composition or the light absorber through the humidification treatment, and promotes the formation of siloxane bonds. In addition, through the humidification treatment, a hard and dense light absorber can be formed in a state where the particles containing the light absorber are not agglomerated.

[0161] Alkoxysilane is not limited to a specific alkoxysilane as long as it can form a hydrolysis-polycondensation compound having a siloxane bond in the light absorber through a hydrolysis reaction and a polycondensation reaction. Alkoxysilane can be, for example, a monomer such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane or 3-glycidoxypropylmethyldiethoxysilane, or a dimer or oligomer formed by bonding a part of them.

[0162] The light absorber 10 and the binder contained in the light absorbing composition may contain a curable resin. The curable resin is not limited to a specific resin. The curable resin can, for example, disperse or dissolve the above-mentioned light absorbing compound containing phosphonic acid and copper components or other light absorbing compounds and maintain them. In addition, the curable resin is preferably in a liquid state in an uncured or unreacted state, and is a resin that can at least disperse or dissolve the above-mentioned light absorbing compound containing phosphonic acid and copper components. Furthermore, the curable resin can be applied to a specified object by spin coating, spray coating, dip coating and distribution to form a coating film when the curable resin contains a light absorbing compound and the resin is in an uncured liquid state. The object to form the coating film is a substrate having a specified surface regardless of whether it is a flat surface or a curved surface. The uncured liquid resin is preferably capable of being cured by a method based on heating, humidification, light energy irradiation, or a combination thereof. Any of the following conditions can be satisfied: as long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the conditions (I) to (V), or the transmission spectrum of a plate-like body having a smooth surface and a thickness of 1 mm formed by curing the resin is 90% or more in a wavelength of 450nm to 800nm. Examples of curable resins are cyclic polyolefin resins, epoxy resins, polyimide resins, modified acrylic resins, silicone resins, and polyethylene resins (PVA) such as polyvinyl butyral (PVB).

[0163] The light absorber 10 and the light absorbing composition may contain a curing catalyst as a catalyst for accelerating the curing of the curable resin. The curing catalyst may be a catalyst capable of controlling conditions such as the curing speed of the curable resin, the reactivity of the curing of the resin, and the hardness of the cured resin.

[0164] The curing catalyst is preferably an organic compound containing a metal component. The organometallic compound is not limited to a specific compound. As the organometallic compound, an organoaluminum compound, an organotitanium compound, an organozinc compound, an organotin compound, etc. can be used.

[0165] The organoaluminum compound is not limited to a specific compound. As the organoaluminum compound, aluminum salt compounds such as aluminum triacetate and aluminum octoate, aluminum trimethoxide, aluminum triethanolate, aluminum dimethanol, aluminum diethanolate, aluminum triallyl alcoholate, aluminum diallyl alcoholate and aluminum isopropoxide, and aluminum methoxy bis (ethyl acetoacetate) aluminum, methoxy bis (ethyl acetoacetone) aluminum, ethoxy bis (ethyl acetoacetate) aluminum, ethoxy bis (ethyl acetoacetate) aluminum, isopropoxy bis (ethyl acetoacetate) aluminum, isopropoxy bis (methyl acetoacetate) aluminum, isopropoxy bis (tert-butyl acetoacetate) aluminum, butoxy bis (ethyl acetoacetate) aluminum, dimethoxy (ethyl acetoacetate) aluminum, dimethoxy (ethyl acetoacetate) aluminum, diethoxy (ethyl acetoacetate) aluminum, diethoxy (ethyl acetoacetate) aluminum, diisopropoxy (ethyl acetoacetate) aluminum, diisopropoxy (methyl acetoacetate) aluminum, three (ethyl acetoacetate) aluminum and three (acetoacetone) aluminum chelate compounds, etc. can be exemplified. They can be used alone or in combination.

[0166] The organic titanium compound is not limited to a specific compound. Examples of the organic titanium compound include titanium chelates such as titanium tetraacetylacetonate, dibutoxy diacetylacetonate titanium, ethyl acetoacetate titanium, octanediol titanium, and titanium lactate; and titanium alkoxides such as tetraisopropyl titanate, tetrabutyl titanate, tetramethyl titanate, tetra(2-ethylhexyl titanate), tetra-2-ethylhexyl titanium, butoxy titanium dimer, titanium tetra-n-butoxide, titanium tetraisopropoxide, and diisopropoxybis(ethyl acetoacetate) titanium. These can be used alone or in combination.

[0167] The organic zirconium compound is not limited to a specific compound. Examples of the organic zirconium compound include zirconium chelates such as zirconium tetraacetylacetonate, zirconium dibutoxybis(ethyl acetoacetate), zirconium monobutoxy acetylacetonate bis(ethyl acetoacetate), zirconium tributoxymonoacetylacetonate, and zirconium tetraacetylacetonate, and zirconium alkoxides such as zirconium tetra-n-butoxide and zirconium tetra-n-propoxide. These can be used alone or in combination.

[0168] Examples of the organic zinc compound include zinc alkoxides such as dimethoxyzinc, diethoxyzinc, and ethylmethoxyzinc, and these can be used alone or in combination of two or more.

[0169] Examples of the organotin compound include tin alkoxides such as dimethyltin oxide, diethyltin oxide, dipropyltin oxide, dibutyltin oxide, dipentyltin oxide, dihexyltin oxide, diheptyltin oxide, and dioctyltin oxide. These can be used alone or in combination of two or more.

[0170] The curing catalyst may further contain at least one of the alkoxide having a metal component and the hydrolyzate of the alkoxide having a metal component as described above. The alkoxide having a metal component and the hydrolyzate of the alkoxide having a metal component are collectively referred to as "metal alkoxide compounds". The metal alkoxide is represented by the general formula M(OR): n (M is a metal element, n is an integer greater than 1) represents a compound in which the hydrogen atom of the hydroxyl group of the alcohol is replaced by a metal element M. Metal alkoxide forms M-OH by hydrolysis, and then forms a MOM bond by reacting with metal alkoxides of other molecules. For example, the light-absorbing composition contains compounds such as curable resins. When the light-absorbing composition with fluidity is cured to form the light absorber 10, the metal alkoxide compound can function as a catalyst to promote the curing of the light-absorbing composition. When the light-absorbing composition is cured by heat treatment, the higher the temperature of the heat treatment, the easier it is to improve environmental resistance such as heat resistance. On the other hand, when the temperature of the heat treatment is high, the characteristics of a part of the light-absorbing compound or the ultraviolet absorber described later may be reduced. If the characteristics of the ultraviolet absorber are reduced, the wavelength of the light absorbed by the ultraviolet absorber may deviate from the predetermined absorption wavelength. It is also possible to cause the absorption capacity of the ultraviolet absorber to decrease or disappear. However, in the case where the light absorber contains a metal alkoxide compound, even if the temperature of the heat treatment is not high, the curing of the light-absorbing composition can be promoted. As a result, the light absorber 10 is prone to high environmental resistance.

[0171] The metal component included in the metal alkoxide compound is not limited to a specific component. The example of its metal component is, for example, Al, Ti, Zr, Zn, Sn and Fe. As metal alkoxide, for example, CAT-AC and DX-9740 manufactured by Shin-Etsu Chemical Co., Ltd., Orgatix AL-3001 manufactured by Matsumoto Fine Chemical Co., Ltd. as aluminum alkoxide, isopropyl aluminum alkoxide manufactured by Tokyo Chemical Industry Co., Ltd., D-20, D-25 and DX-175 manufactured by Shin-Etsu Chemical Co., Ltd. as titanium alkoxide, Orgatix TA-8, TA-21, TA-30, TA-80 and TA-90 manufactured by Matsumoto Fine Chemical Co., Ltd. as zirconium alkoxide, D-15 and D-31 manufactured by Shin-Etsu Chemical Co., Ltd., and Orgatix ZA-45 and ZA-65 manufactured by Matsumoto Fine Chemical Co., Ltd. as zirconium alkoxide.

[0172] In the light absorber 10 and the light absorbing composition, the ratio of the content of the copper component to the content of the metal component contained in the metal alkoxide compound is γ MC Not limited to a specific value. MC For example, 1×102 ~7×10 2 , preferably 2×10 2 ~6×10 2 , more preferably 3×10 2 ~5×10 2 .

[0173] In the light absorber 10 and the light absorbing composition, the ratio of the content of the phosphorus component to the content of the metal component contained in the metal alkoxide compound is γ MP Not limited to a specific value. MP For example, 0.5×10 2 ~5×10 2 , preferably 1×10 2 ~4×10 2 , more preferably 1.5×10 2 ~3×10 2 .

[0174] The light absorber 10 and the light absorbing composition may include an ultraviolet absorber that absorbs a portion of the light belonging to the ultraviolet rays. As long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the conditions of (I) to (V), the ultraviolet absorber is not limited to a specific compound. The ultraviolet absorber is, for example, a compound that does not have both hydroxyl and carbonyl groups in the molecule. When expressed as a structural formula, it is a compound that does not have both hydroxyl and carbonyl groups in one molecule. The curing of the light absorbing composition can be promoted by the coordination of a reaction substance or a precursor to a specific position in a molecule such as an alkoxide having a metal component. For example, if there is a group that is easily coordinated by a substance other than a substance used for the reaction of curing the light absorbing composition, the effect of the catalyst may be weakened. In particular, both hydroxyl and carbonyl groups have high electron donating properties, and alkoxide compounds react or coordinate with ultraviolet absorbers having these groups, and a part of them form a complex, thereby changing the ultraviolet absorption characteristics originally possessed by the ultraviolet absorber. However, when the ultraviolet absorber is a compound that does not have both hydroxyl and carbonyl groups in the molecule, it is difficult for the alkoxide compound to form a complex with the ultraviolet absorber, and it is easy to exert the original ultraviolet absorption characteristics of the ultraviolet absorber. It should be noted that the ultraviolet absorber may contain only one of the hydroxyl and carbonyl groups in the molecule.

[0175] The ultraviolet absorber is preferably selected from the aspects of absorbing light of a desired wavelength range, having compatibility with a specific solvent, being well dispersed in a light absorbing composition, particularly a curable resin, and having excellent environmental resistance. Examples of ultraviolet absorbers are benzophenone compounds, benzotriazole compounds, salicylic acid compounds, and triazine compounds. For example, as ultraviolet absorbers, Tinuvin PS, Tinuvin 99-2, Tinuvin 234, Tinuvin 326, Tinuvin 329, Tinuvin 900, Tinuvin 928, Tinuvin 405, and Tinuvin 460 can be used. These are ultraviolet absorbers manufactured by BASF, and Tinuvin is a registered trademark.

[0176] The content of the ultraviolet absorber in the light absorber is not limited to a specific value as long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the conditions (I) to (V). By containing a small amount of ultraviolet absorber, a high light absorption capacity can be exerted. The ratio of the content of the ultraviolet absorber in the light absorber 10 to the content of the copper component is, for example, 0.01 to 1, preferably 0.02 to 0.5, and more preferably 0.07 to 0.14 on a mass basis. The ratio of the content of the ultraviolet absorber in the light absorber to the content of the phosphorus component is, for example, 0.02 to 2, preferably 0.04 to 1, and more preferably 0.12 to 0.26 on a mass basis.

[0177] The light-absorbing dispersion contains at least a light-absorbing compound (light absorber) and a solvent. The light-absorbing dispersion may contain a dispersant that helps disperse the light-absorbing compound. For example, a light-absorbing composition is obtained by adding an appropriate curable resin to the light-absorbing dispersion. For example, the light absorber 10 is produced by curing the light-absorbing composition.

[0178] The light-absorbing dispersion may contain, for example, a solvent, a light-absorbing compound containing phosphonic acid and copper components, and a phosphate ester that helps disperse the light-absorbing compound in the solvent. The light-absorbing dispersion does not substantially contain a curable resin. Therefore, there is no concern that the dispersion will solidify during the circulation of the light-absorbing dispersion, and a person who wants to obtain the light absorber 10 can mix the light-absorbing dispersion with a separately prepared curable resin to prepare a light-absorbing composition as a precursor of the light absorber 10. The reduced concern about the solidification or thickening of the material during the circulation of the product also helps to extend the shelf life or usable life of the dispersion.

[0179] The light-absorbing dispersion does not substantially contain a curable resin, which means that even if the light-absorbing dispersion is subjected to external energy such as heating or irradiation with electromagnetic waves (including visible light, ultraviolet rays, etc.), it will not cure. The light-absorbing dispersion may contain a curable resin to the extent that no curing occurs. The type of energy imparted for curing the curable resin mixed with the light-absorbing dispersion is not limited. The impartment of energy includes heating and irradiation with electromagnetic waves such as light. For example, as a broad sense of heating, curing by placing (standing) at normal room temperature (20°C to 28°C) is also included in the impartment of energy. The light-absorbing dispersion does not contain a curable resin, such as a curable epoxy resin, a phenolic resin, a melamine resin, an unsaturated polyester resin, an alkyd resin, a silicone resin, a polyurethane resin, a polyimide resin, an acrylic resin, a urea-formaldehyde resin, and a modified body thereof. Curable acrylic resins include modified acrylate resins such as epoxy acrylates and polyurethane acrylates. Furthermore, in the case where the light-absorbing dispersion does not substantially contain a curable resin, at least no curing occurs. On the other hand, curable resins are sometimes supplied in two or more liquids, such as a combination of the present agent and a curing agent and a combination of the present agent and a catalyst. Considering certain situations of such a group of curable resins, the light-absorbing dispersion liquid as a specific example of the present invention includes a system containing the present agent without a curing agent or a catalyst.

[0180] The light-absorbing dispersion may contain a first phosphonic acid and a second phosphonic acid. The light-absorbing compound containing an alkylphosphonic acid has high absorption at wavelengths from 800 nm to 1200 nm in the near-infrared region, and the light-absorbing compound containing an arylphosphonic acid has high absorption for light of a wavelength near 680 nm. It is often meaningful for the light-absorbing dispersion to contain both the first phosphonic acid and the second phosphonic acid. In the light-absorbing dispersion, the light-absorbing compound containing an arylphosphonic acid and a copper component, and the light-absorbing compound containing an alkylphosphonic acid and a copper component may be contained in a solvent that does not contain the above-mentioned curable resin.

[0181] The solvent contained in the light absorbing dispersion is not limited to a specific solvent. The solvent contained in the light absorbing dispersion is, for example, an organic solvent. The solvent contained in the light absorbing dispersion is not limited to these, and can be tetrahydrofuran (THF), toluene, acetone, acetonitrile, acetylacetone, allyl alcohol, benzene, benzyl alcohol, butanol, methyl ethyl ketone, butanol, epichlorohydrin, cresol, methanol, ethanol, or a mixture of two or more organic solvents selected from these.

[0182] The light-absorbing dispersion has, for example, a specific transmission spectrum. The light-absorbing dispersion has, for example, a transmission spectrum that satisfies the following (i), (ii), (iii), and (iv). The transmission spectrum is obtained by, for example, normalizing the transmission spectrum obtained by incident light of a wavelength of 300 nm to 1600 nm into the light-absorbing dispersion so that the transmittance at a wavelength of 700 nm is 20%.

[0183] (i) Average value T of transmittance in the wavelength range of 460 nm to 600 nm A DP(460-600) More than 85%.

[0184] (ii) Short-wavelength side cutoff wavelength λ at which the transmittance reaches 50% in the wavelength range of 350 nm to 450 nm H DP(S) It is 380nm~420nm.

[0185] (iii) Long-wavelength side cutoff wavelength λ at which the transmittance reaches 50% in the wavelength range of 600 nm to 700 nm H DP(L) It is 600nm~650nm.

[0186] (iv) Average value T of transmittance in the wavelength range of 725 nm to 1000 nm A DP(725-1000) It is 5% to 20%.

[0187] The dispersion of the light absorbing compound is prepared, for example, by dispersing the light absorbing compound in toluene at a predetermined concentration. Then, the dispersion is placed in a commercially available quartz cuvette to prepare a workpiece for measurement, and the transmission spectrum of the workpiece is measured using a spectrophotometer, and the transmission spectrum of the dispersion of the light absorbing compound is obtained by subtracting the baseline. In addition, the transmittance is standardized in the measurement wavelength range so that the transmittance at a wavelength of 700nm becomes 20%. It should be noted that the baseline is obtained, for example, by placing toluene without the light absorbing compound in the same quartz cuvette and measuring the transmission spectrum using a spectrophotometer.

[0188] When the transmission spectrum of the dispersion of the light-absorbing compound satisfies the above conditions (i) to (iv), a light absorber produced by curing a light-absorbing composition obtained by mixing the dispersion with various curable resins or an optical filter having the light absorber is likely to satisfy the above conditions (I) to (V).

[0189] Short wavelength side cutoff wavelength λ H DP(S) It can be 390nm to 410nm. Long wavelength side cutoff wavelength λ H DP(L)It can be 610nm to 640nm, or 615nm to 635nm.

[0190] The transmission spectrum of the dispersion liquid of the light absorbing compound may satisfy the following conditions (v), (vi), (vii) and (viii).

[0191] (v) Wavelength λ corresponding to the minimum transmittance in the wavelength range of 700 nm to 1500 nm min DP(700-1500) In the range of 750nm~950nm.

[0192] (vi) The difference λ between the maximum wavelength and the minimum wavelength at which the transmittance reaches 20% in the wavelength range of 600 nm to 1500 nm range(20) DP(600-1500) It is 350nm~600nm.

[0193] (vii) The difference λ between the maximum wavelength and the minimum wavelength at which the transmittance reaches 50% in the wavelength range of 600 nm to 1500 nm range(50) DP(600-1500) It is 600nm~750nm.

[0194] (viii) The difference λ between the maximum wavelength and the minimum wavelength at which the transmittance reaches 50% in the wavelength range of 350 nm to 700 nm range(50) DP(350-700) It is 180nm~280nm.

[0195] When the transmission spectrum of the dispersion of the light-absorbing compound satisfies the above conditions (v) to (viii), a light absorber produced by curing a light-absorbing composition obtained by mixing the dispersion with various binders or an optical filter having the light absorber is more likely to satisfy the above conditions (I) to (V).

[0196] Wavelength min DP(700-1500) It can be in the range of 800nm ​​to 900nm or in the range of 820nm to 880nm. range(20) DP(600-1500) It can also be 400nm to 550nm. range(50) DP(600-1500) It can be 620nm to 720nm, or 630nm to 710nm. range(50) DP(350-700) It may be 190nm to 260nm, or 200nm to 250nm.

[0197] In the optical filter 1a, the thickness of the light absorber 10 is not limited to a specific thickness. Its thickness is, for example, about 200 nm or less, which greatly contributes to the low height of the device. On the other hand, the optical filter 1b having the substrate 20 tends to have high rigidity or mechanical strength, and a rigid optical filter can be provided.

[0198] The substrate 20 is not limited to a specific substrate. The substrate 20 can be selected, for example, so that the optical filter 1b satisfies the above conditions (I) to (V), or can be selected so that the conditions (VI) and (VII) are further satisfied. The substrate 20 can also be selected so that the optical filter 1b satisfies the above conditions (1-i) to (1-iv) and the conditions (2-i) to (2-iv).

[0199] The shape of the substrate 20 is not limited to a specific shape. Figure 1B As shown, the substrate can be in the form of a flat plate. In this case, it is considered that it is easy to apply the light-absorbing composition when the substrate 20 is used as a support for the filter 1b, and the versatility as a filter is also high. On the other hand, the substrate 20 may include a curved surface, and may also have a convex or concave surface. The substrate 20 may also be in a shape other than a plate. For example, examples of the substrate 20 are optical elements such as lenses, polarizing elements, prisms, reflective elements, and diffraction gratings. These optical elements can have surfaces including curved surfaces and flat surfaces. In addition, another example of the substrate 20 is a photoelectric conversion element such as a photodiode and a phototransistor, an image sensor in which a plurality of photoelectric conversion elements such as a CCD or a CMOS are arranged, or an image sensor equivalent to the image sensor, and a microlens array integrated with an imaging element. Another example of the substrate 20 is a display device such as a display of a portable information terminal.

[0200] The substrate 20 may be transparent. When the substrate 20 is transparent, the transmission spectrum of the light absorber 10 is easily reflected in the transmission spectrum of the filter 1b having the light absorber 10 and the substrate 20. In the transmission spectrum of a 3 mm thick flat plate formed of the same material as the substrate 20, the transmittance can be 90% or more in the wavelength range of 360nm to 900nm, and the transmittance can be 85% or more in the wavelength range of 350nm to 1200nm. A typical example of the substrate 20 having such transparency is a glass substrate. The substrate 20 can be a silicate glass such as soda lime glass and borosilicate glass, or a phosphate glass or fluorophosphate glass containing coloring components such as Cu and Co. Phosphate glass and fluorophosphate glass containing coloring components are, for example, infrared absorbing glass, which itself has light absorption. When the light absorber is used together with the substrate of infrared absorbing glass, the light absorption and transmission spectrum of both can be adjusted to produce a filter with desired optical characteristics, and the design freedom of the filter is high.

[0201] In addition, a typical example of the substrate 20 is a resin substrate. The resin contained in the resin substrate is a cycloolefin resin such as a norbornene resin, a polyarylate resin, an acrylic resin, a modified acrylic resin, a polyimide resin, a polyetherimide resin, a polyolefin resin, a polysulfone resin, a polyethersulfone resin, a polycarbonate resin or a silicone resin. Compared with glass, resin has significantly higher processability and higher formability. Thus, it is easy to prepare substrates of various shapes such as optical elements.

[0202] In order to reduce the reflectivity or increase the transmittance of light of a predetermined wavelength, an antireflection film or an antireflection film may be provided on the surface of the light absorber 10 or the optical filter including the light absorber 10 . Figure 1C to Figure 1D An example of an optical filter including a light absorber 10 and an antireflection film is shown respectively.

[0203] exist Figure 1C In the optical filter 1c shown, an antireflection film 31a is disposed on one main surface of the light absorber 10, and an antireflection film 32a is disposed on the other main surface. The antireflection film 31a and the antireflection film 32a are each an antireflection film of a single-layer structure.

[0204] exist Figure 1D In the optical filter 1d shown, an antireflection film 31b is disposed on one main surface of the light absorber 10, and an antireflection film 32b is disposed on the other main surface. The antireflection film 31b and the antireflection film 32b are each an antireflection film of a two-layer structure.

[0205] exist Figure 1E In the optical filter 1e shown, an antireflection film 31c is arranged on one main surface of the light absorber 10, and an antireflection film 32c is arranged on the other main surface. The antireflection film 31c and the antireflection film 32c are each an antireflection film of a three-layer structure.

[0206] exist Figure 1F In the optical filter 1f shown, an antireflection film 31d is disposed on one main surface of the light absorber 10, and an antireflection film 32d is disposed on the other main surface. The antireflection film 31d and the antireflection film 32d are each a multilayer antireflection film having three or more layers.

[0207] When the optical filter includes a transparent substrate and the light absorber 10 formed on the transparent substrate, an antireflection film may be formed on the surface of the light absorber 10 and the surface of the transparent substrate that is not in contact with the light absorber 10 .

[0208] The antireflection film can increase the transmittance of the light absorber 10 or the optical filter including the light absorber 10 in the wavelength band of light that can pass through the light absorber 10 or the optical filter including the light absorber 10, i.e., the transmission band. The transmission band may be a band in which the transmittance reaches 50% or more in the transmission spectrum of the light absorber 10 or the optical filter including the light absorber 10.

[0209] When an anti-reflection film is formed on the light absorber 10, an optical filter having the light absorber 10, or a transparent substrate for supporting them (for example, D263T eco from Corning), the reflectivity at a wavelength of 400nm to 600nm when light with a wavelength of 300nm to 1200nm is incident at an incident angle of 5° is, for example, 1% or less, preferably 0.5% or less, and more preferably 0.25% or less.

[0210] When an anti-reflection film is formed on the light absorber 10, the optical filter having the light absorber 10, or the transparent substrate supporting them, the average value of the reflectance in the wavelength 700nm to 1200nm when light of a wavelength of 300nm to 1200nm is incident at an incident angle of 5° is, for example, 1% or less, preferably 0.5% or less, and more preferably 0.25% or less. As a result, part of the infrared light is reflected, and the obtained image is less likely to have ghosting or flare.

[0211] In the optical filter including the light absorber 10 and the anti-reflection film, when light with a wavelength of 300 nm to 1200 nm is incident at an incident angle of 50°, the reflectivity in the wavelength range of 400 nm to 600 nm is, for example, 3% or less, preferably 1% or less. In addition, in the optical filter, when light with a wavelength of 300 nm to 1200 nm is incident at an incident angle of 50°, the average reflectivity in the wavelength range of 700 nm to 1200 nm is, for example, 3% or less, preferably 1.5% or less. Thus, even when the incident angle to the light absorber 10 or the optical filter including the light absorber 10 becomes large, it is easy to prevent the reflection of light.

[0212] The antireflection film is not limited to a specific film. The antireflection film includes, for example, at least one layer selected from the group consisting of the following (a), (b), and (c). The antireflection film may be a combination of two or more layers.

[0213] (a) Layer formed by a sol-gel method using a reactive material containing silicon

[0214] (b) A layer formed by a sol-gel method using a reactive material containing silicon, the layer further containing fine particles.

[0215] (c) Layers formed by physical film forming methods such as vacuum evaporation and sputtering

[0216] Regarding the layers of (a) and (b) above, the reactive material containing silicon is not limited to a specific material, and the functional group contained in the reactive material is not limited to a specific functional group. The reactive material containing silicon preferably contains trifunctional silanes such as methyltriethoxysilane (MTES) and tetrafunctional silanes such as tetraethoxysilane (TEOS). Tetrafunctional silanes are important for forming a coating film with a firm and dense skeleton. On the other hand, when only tetrafunctional silanes are used, the following problems may arise: it is difficult to control reactivity, the selectivity of porosity is lacking, and cracks are easily generated. By using trifunctional silanes on the basis of tetrafunctional silanes, the flexibility of the silica skeleton is improved and the selectivity of porosity is improved. Therefore, the refractive index required for the anti-reflection film can be adjusted (adjustment of porosity). In addition, it is also easy to suppress the generation of cracks. The organic functional group attached to the trifunctional silane is not particularly limited. It is preferred to use a trifunctional silane having a methyl group in combination with a tetrafunctional silane. This is because a homogeneous liquid and a coating film can be easily formed. The amount of trifunctional silane and tetrafunctional silane is preferably in the range of the amount of trifunctional silane: the amount of tetrafunctional silane = 5:1 to 1:3. Thus, the trifunctional silane can suppress the generation of cracks in the anti-reflection film, and the tetrafunctional silane can form a strong skeleton. The reactive material containing silicon may contain difunctional silane. The raw material of the layer (a) above may contain components other than those related to the sol-gel method.

[0217] The above-mentioned trifunctional silane is not limited to a specific silane. Examples of the trifunctional silane include methyltriethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, ethyltrimethoxysilane, propyltriethoxysilane, propyltrimethoxysilane, butyltriethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, hexyltriethoxysilane and hexyltrimethoxysilane, and may also be a trifunctional silane having an alkyl group directly bonded to a silicon atom (Si). The tetrafunctional silane is not limited to a specific silane. Examples of the tetrafunctional silane include tetraethoxysilane, tetramethoxysilane, tetrapropoxysilane and tetrabutoxysilane.

[0218] All silane compounds generate hydrolyzates of silane compounds containing silanol groups by hydrolysis, and then by polycondensation of these hydrolyzates, trifunctional silane is changed to (poly) silsesquioxane, and tetrafunctional silane is changed to silicon dioxide. The refractive index of (poly) silsesquioxane and silicon dioxide is as low as about 1.46, so a layer with a low refractive index can be formed. Therefore, a layer containing at least one selected from the group consisting of (poly) silsesquioxane and silicon dioxide is suitable as a layer included in the anti-reflection film of the light absorber 10 or the filter having the light absorber 10.

[0219] In the formation of the layers (a) and (b), for example, a coating film of a liquid composition containing a reactive material containing silicon may be formed and the coating film may be fired. The coating film may be fired at, for example, 60°C to 170°C, preferably 60°C to 150°C, and more preferably 60°C to 115°C.

[0220] Regarding the layer of (b) above, a reactive material containing silicon, a hydrolyzate of the reactive material, or a condensate of the hydrolyzate may contain a granular compound. Such a granular compound is, for example, microparticles containing silicon dioxide, titanium dioxide, zirconium oxide, or aluminum oxide. The refractive index of the material forming the microparticles is, for example, 1.40 to 2.55. The material constituting the microparticles is preferably silicon dioxide. In a layer containing at least one selected from the group consisting of silicon dioxide and (poly) silsesquioxane, they act as a binder surrounding the microparticles. Therefore, the bonding force between the microparticles and the binder is enhanced via silanol groups, etc., and it can be expected that reliability such as weather resistance will be improved.

[0221] The microparticles contained in the layer (b) may be hollow microparticles. Hollow microparticles have empty spaces inside, so their refractive index tends to be very low. The refractive index of hollow microparticles is, for example, 1.02 to 1.50.

[0222] The average particle size of the hollow fine particles is, for example, 5 nm to 200 nm. The average particle size of the hollow fine particles can be determined, for example, by measuring the maximum diameters of 50 or more particles randomly selected from the cross section of the layer (b) using an optical microscope, an electron microscope, or a metal microscope, and taking the arithmetic average of the maximum diameters.

[0223] The content of the hollow fine particles in the layer (b) is, for example, 5 to 95% by mass.

[0224] By making the layer (b) contain hollow particles, the refractive index of the layer tends to become very low. In the case where the layer (b) contains hollow particles, the refractive index of the layer (b) is, for example, 1.00 to 1.45 (excluding 1.00). As hollow particles, Thrulya 4110 manufactured by JGC Catalysts & Chemicals Co., Ltd. can be used.

[0225] In a layer comprising at least one selected from the group consisting of silica and (poly)silsesquioxane, if a comparison is made between a case where hollow particles are included and a case where hollow particles are not included, the refractive index of the layer is likely to be lower in the case where hollow particles are included. The light absorber 10 or the optical filter having the light absorber 10 may constitute an anti-reflection film in a manner that a layer comprising at least one selected from the group consisting of silica and (poly)silsesquioxane and hollow particles, and a layer comprising at least one selected from the group consisting of silica and (poly)silsesquioxane and not containing hollow particles are sequentially arranged. In this case, it is sometimes expected that the anti-reflection effect can be improved.

[0226] The microparticles contained in the layer of (b) above may be solid microparticles. The refractive index of the solid microparticles is, for example, 1.25 to 1.65, and more preferably 1.30 to 1.65. When the layer of (b) above contains solid microparticles, the refractive index of the layer of (b) is, for example, 1.10 to 1.55. The average particle size of the solid microparticles is, for example, 2 nm to 200 nm. The average particle size of the solid microparticles can be determined in the same manner as the average particle size of the hollow microparticles. As solid microparticles, for example, SNOWTEXMP-2040 manufactured by Nissan Chemical Co., Ltd. can be used.

[0227] The layer (b) may contain microparticles having a relatively high refractive index. Thus, the layer (b) tends to have a high refractive index. In this case, the microparticles may contain a material selected from TiO 2 (Titanium oxide, refractive index 2.33-2.55), Ta 2 O 5 (Tantalum oxide, refractive index 2.16), Nb 2 O 5 (niobium oxide, refractive index 2.33) and Si 3 N 4 At least one material selected from the group consisting of (silicon nitride, refractive index 2.02). The microparticles may contain two or more materials. The layer (b) preferably contains TiO 2 In this case, the refractive index of the layer (b) tends to be high, for example, it is possible to obtain a refractive index similar to that of the layer containing silicon dioxide (SiO 2 ) is a low refractive index film of hollow particles compared with a high refractive index film. The layer (b) contains TiO 2 In the case of fine particles, the refractive index of the layer is, for example, 1.50 to 2.30. In the example of the layer (b) above, the refractive index of the film can be controlled by adjusting the content of fine particles and the like relative to the amount of the components included in the film.

[0228] TiO 2 The average particle size of the fine particles is, for example, 2 nm to 200 nm. 2The average particle size of the fine particles can be determined in the same manner as the average particle size of the hollow fine particles. 2 The content of the fine particles is, for example, 2% to 50% by mass. 2 As the fine particles, for example, NS405 manufactured by Tayca Corporation or TTO-51A manufactured by Ishihara Sangyo Co., Ltd. can be used.

[0229] The particles contained in the layer (b) can be surface treated with coupling agents such as silane coupling agents and titanium coupling agents before being mixed with a binder or a matrix. Thus, the adhesion or wettability between the binder or the matrix and the particles is easily improved. These surface treatments are performed using TiO 2 and SiO 2 It is also effective in the case of particles other than

[0230] For example, the anti-reflection film can be composed of a combination of a low refractive index layer, a medium refractive index layer and a high refractive index layer. The low refractive index layer is, for example, a layer comprising at least one selected from the group consisting of silica and (poly) silsesquioxane and containing hollow particles. The medium refractive index layer is a layer comprising at least one selected from the group consisting of silica and (poly) silsesquioxane and not containing hollow particles. The high refractive index layer is a layer comprising at least one selected from the group consisting of silica and (poly) silsesquioxane and containing TiO 2 In the combination of the low refractive index layer, the medium refractive index layer and the high refractive index layer in the antireflection film, the antireflection film can be constructed in consideration of conditions such as the thickness of each layer, the number of each layer and the repeated pattern of these layers.

[0231] The layer of (c) can be formed by physical methods such as vacuum evaporation including ion-assisted evaporation (IAD), sputtering, and ion plating. These methods are collectively referred to as evaporation. According to the evaporation method, as the layer of (c), a layer including a dielectric and a metal oxide is obtained. The material of the layer of (c) formed by the evaporation method is not limited to a specific material. The material of the layer of (c) includes, for example, a material selected from SiO 2 、TiO 2 、 2 O 3 SnO 2 、In 2 O 3 , Nb 2 O 5 、Si 3 N 4 、TiN x and MgF 2 The layer (c) may be a layer formed by mixing two or more inorganic compounds selected from these inorganic compounds at a predetermined ratio.

[0232] The layer (c) may have a single-layer structure composed of only the same material, or may have a multilayer structure in which two or more layers composed of different materials (or mixed materials) selected from the above-mentioned inorganic compounds are stacked. In the case where the antireflection film is a multilayer film, for example, a layer composed of TiO 2 、 2 O 3 and Nb 2 O 5 The layer composed of a material having a relatively high refractive index such as SiO 2 and MgF 2 The antireflection film is formed by alternately laminating layers composed of materials having relatively low refractive indices such as MgO, MgO, and MgO or a mixture of these materials while adjusting the thickness of these layers and the number of repetitions of lamination of these layers.

[0233] The filter with the light absorber 10 can be used for an ambient light sensor. An ambient light sensor is a device that is mounted on a device and detects the brightness or color tone of the device's surroundings. The ambient light sensor is used to identify the properties of the light around the device, for example, to automatically adjust the brightness of a display device such as a display mounted on the device. An ambient light sensor is sometimes also called a luminance sensor or an illuminance sensor.

[0234] Figure 2A FIG. 1 is a cross-sectional view showing an example of an ambient light sensor. Figure 2A As shown, the ambient light sensor 2 includes, for example, a circuit substrate 3, a photoelectric conversion element 4, a housing 5, and an optical filter 1a. The ambient light sensor 2 detects, for example, the properties of light belonging to the visible light region among the properties of light around a device having the ambient light sensor 2. The circuit substrate 3 supports the ambient light sensor 2 and electrically connects the ambient light sensor 2 to peripheral devices. The photoelectric conversion element 4 is disposed on the circuit substrate 3 and includes, for example, elements such as a photodiode or a phototransistor. The housing 5 is disposed on the circuit substrate 3 and surrounds the photoelectric conversion element 4. The optical filter 1a is, for example, disposed in front of the photoelectric conversion element 4 to shield a portion of light traveling toward the photoelectric conversion element 4. The optical filter 1a shields, for example, a portion of light belonging to ultraviolet rays or infrared rays. The optical filter 1a is supported by the housing 5.

[0235] Ambient light sensors can be used as Figure 2A As shown in FIG. 1 , a filter having a light absorber 10 may be provided. Figure 2B As shown in the figure, an integrated photoelectric conversion element is provided in which the light absorber 10 and the photoelectric conversion element are integrated. Figure 2BThe photoelectric conversion element 2b shown has a light receiving surface 2f and a light absorber 10. In the photoelectric conversion element 2b, the light receiving surface 2f and the light absorber 10 are arranged in sequence. The photoelectric conversion element 2b is an integrated photoelectric conversion element. The integrated photoelectric conversion element is obtained, for example, by coating the above-mentioned light absorbing composition on the surface of the light receiving surface (window) of the photoelectric conversion element and curing it to form the light absorber 10. When such a photoelectric conversion element is used, there is no need to use the light absorber separately from the photoelectric conversion element. According to such an ambient light sensor, light outside the visible light region, such as a part of ultraviolet rays or infrared rays, can be shielded by absorption in the light absorber 10. As an ambient light sensor dedicated to detecting light in a roughly visible light region, the ease of operation of the ambient light sensor can be significantly improved. In addition, simplification of the supply chain of product distribution can also be expected.

[0236] In the photoelectric conversion element 2b, for example, a first electrode E1 and a photoelectric conversion layer L are sequentially stacked on a circuit board 3. Furthermore, on the photoelectric conversion layer L, a second electrode E2, a light receiving surface 2f, and a light absorber 10 are arranged.

[0237] In order to reduce reflectivity and increase transmittance of light of a predetermined wavelength, an antireflection film or an antireflection film may be provided on the surface of the light absorber 10 or the filter including the light absorber 10 mounted on the ambient light sensor.

[0238] The optical filter having the light absorber 10 can be used in an imaging device or a camera module. The imaging device or the camera module, for example, has an image sensor, a circuit substrate, a lens system, and an optical filter having the light absorber 10. In the image sensor, for example, a plurality of photoelectric conversion elements such as CCD or CMOS are arranged. The circuit substrate electrically connects the image sensor to an external device. The lens system includes one or more lens groups for focusing light from a subject, etc., on the image sensor and forming an image. The optical filter having the light absorber 10 can shield a portion of light belonging to ultraviolet rays and infrared rays.

[0239] For example, in an imaging device equipped with an optical filter having a light absorber 10, part of the light belonging to ultraviolet rays and infrared rays is shielded by absorption, and light belonging to the visible light region passes through the optical filter toward the image sensor. In the case where the optical filter has a function of reflecting part of the light by a dielectric multilayer film or the like, part of the light reflected by the optical filter is reflected inside the housing or on the surface of a lens system arranged in front of the optical filter, or part of the reflected light projects an aperture or its shape and reaches the light receiving surface of the imaging element, thereby making phenomena such as ghosting and flare that deteriorate the contrast more obvious. On the other hand, according to an imaging device equipped with an optical filter having a light absorber 10, such phenomena are less likely to occur, and ghosting and flare are less likely to be conspicuous in the acquired image.

[0240] Figure 3A 1 is a diagram showing an example of an imaging device. This diagram shows an overview of the imaging device, and only the elements necessary for explanation are schematically described, and other parts or elements are omitted. Figure 3A As shown in FIG. 1 , the imaging device 6a includes an image sensor 7, a lens system 8, and an optical filter 1a. In the imaging device 6a, the optical filter 1a is disposed, for example, between the image sensor 7 and the lens system 8 and directly in front of the image sensor 7. The arrangement of the optical filter is not limited to Figure 3A The optical filter may also be arranged in front of the lens system 8, that is, on the object side. In this case, the optical filter includes, for example, a light absorber 10 and a transparent dielectric substrate supporting the light absorber 10. If a rigid substrate such as a glass substrate is used as the transparent dielectric substrate, the optical filter can be expected to function as a protective filter for protecting the imaging device and the lens system from the outside.

[0241] Figure 3B 6b is a diagram showing another example of an imaging device. The imaging device 6b is configured similarly to the imaging device 6a except for the parts specifically described. Figure 3B As shown, in the imaging device 6a, a light absorber 10 is arranged on the surface of a part of the lens 8a included in the lens system 8. For example, the above-mentioned light absorbing composition can be applied to the surface of the lens 8a and cured, and the light absorber 10 can be arranged in a manner to form an interface with the lens 8a. Thus, even if a light absorbing filter is not provided separately from the lens system 8, the lens system 8 can have the desired light shielding property, and thus a significant simplification of the assembly or manufacture of the imaging device can be expected. The lens 8a in which such a light absorber 10 is integrally formed, or the lens system including such a lens 8a, can be circulated. An anti-reflection film or a reduced reflection film can also be formed on the surface of the light absorber 10. Thus, the reflected light from the surface of the light absorber 10 is reduced, and the transmitted light in the visible light region is easily increased. In the imaging device 6b, the configuration of the light absorber 10 is not limited to Figure 3B Configuration shown.

[0242] In the lens system of the imaging device, a group of lenses formed by bonding the surfaces of two or more lenses to each other is sometimes included. In order to bond the lenses to each other, an adhesive or a curable resin can be used. Although not shown in the figure, the above-mentioned light-absorbing composition, the above-mentioned light-absorbing dispersion, or the above-mentioned light-absorbing compound can also be included in an adhesive or the like for bonding the lenses to each other. In this case, the light absorber 10 is not easily affected by the external environment of the lens system, and it is expected that the light absorber 10 or the components contained in the light absorber 10 will be protected. If the curable resin is selected in a manner that the refractive index of the light absorber 10 and the lens is roughly the same, the reflection at the interface between the light absorber 10 and the lens can be significantly reduced, and the advantage of not requiring an anti-reflection coating can be obtained.

[0243] Example

[0244] The present invention will be described in more detail by way of examples. It should be noted that the present invention is not limited to the following examples.

[0245] <Example 1>

[0246] 4.500 g of copper acetate monohydrate was mixed with 240 g of tetrahydrofuran (THF) and stirred for 3 hours to obtain a copper acetate solution. Then, 1.77 g of Plysurf A208N (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a phosphate compound was added to the obtained copper acetate solution and stirred for 30 minutes to obtain liquid A. 40 g of THF was added to 0.552 g of phenylphosphonic acid and stirred for 30 minutes to obtain liquid B. 40 g of THF was added to 3.308 g of 4-bromophenylphosphonic acid and stirred for 30 minutes to obtain liquid C. 40 g of THF was added to 0.588 g of n-butylphosphonic acid and stirred for 30 minutes to obtain liquid D. To the mixed solution obtained by mixing solution A, solution B, solution C and solution D, 6.68 g of methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-13) and 2.19 g of tetraethoxysilane (special grade manufactured by KISHIDA CHEMICAL Co., Ltd.) were further added, and the mixture was stirred for 1 minute to obtain solution E. Next, 120 g of toluene was added to the solution E, and the mixture was stirred at room temperature for 1 minute to obtain solution F. The solution F was placed in a flask, and while being heated with an oil bath (manufactured by Tokyo Rikaki Co., Ltd., model: OSB-2100), a desolvation treatment was performed using a rotary evaporator (manufactured by Tokyo Rikaki Co., Ltd., model: N-1110SF). The set temperature of the oil bath was adjusted to 105°C. Thereafter, the desolvation-treated liquid was taken out from the flask. In this way, a dispersion (liquid G) of the light-absorbing compound of Example 1 containing phosphonic acid and copper components was obtained.

[0247] Table 1 shows the raw materials and the added amounts of the raw materials in the preparation of the light absorbing compound and the dispersion of the light absorbing compound in Example 1. Table 2 shows the ratio of the content of phosphonic acid, copper component, and phosphate ester contained in the dispersion of the light absorbing compound on an amount basis or a mass basis. It should be noted that the dispersion of the light absorbing compound in Example 1 contains the light absorbing compound contained in the light absorber, and does not contain a curable resin and a curing catalyst.

[0248] 8.98 g of a silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300), 0.16 g of a catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., product name: CAT-AC), 6.96 g of methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-13) as a trifunctional alkoxysilane, 4.05 g of tetraethoxysilane (special grade manufactured by KISHIDACHEMICAL Co., Ltd.) as a tetrafunctional alkoxysilane, and 4.07 g of dimethyldiethoxysilane (DMDES) (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-22) as a difunctional alkoxysilane were mixed and stirred for 30 minutes to obtain a liquid curable resin (H liquid) that acts as a binder or matrix resin.

[0249] Next, the G liquid as a dispersion of the light absorbing compound and the H liquid as a curable resin were mixed and stirred for 30 minutes to obtain the light absorbing composition of Example 1. Table 1 shows the raw materials of the curable resin, curing catalyst, and alkoxysilane used in the preparation of the light absorbing composition of Example 1 and their addition amounts.

[0250] 0.1 g of a surface antifouling coating agent (manufactured by Daikin Industries, Ltd., product name: OPTOOL DSX, active ingredient concentration: 20% by mass) and 19.9 g of a hydrofluoroether-containing liquid (manufactured by 3M, product name: Novec 7100) were mixed and stirred for 5 minutes to prepare a fluorine treatment agent (active ingredient concentration: 0.1% by mass). The fluorine treatment agent was applied to one main surface of a borosilicate glass (manufactured by SCHOTT, product name: D263 Teco) having a size of 130 mm × 100 mm × 0.70 mm. Thereafter, the glass substrate was placed at room temperature for 24 hours to dry the coating of the fluorine treatment agent, and then the glass surface was gently wiped with a dust-free cloth containing Novec 7100 to remove excess fluorine treatment agent. A fluorine treatment substrate was prepared in this way.

[0251] The light absorbing composition of Example 1 is applied to the central area of ​​one main surface of the fluorine-treated substrate in an area of ​​80 mm × 80 mm using a dispenser to form a coating. After the obtained coating is fully dried at room temperature, it is placed in an oven and fully heated in the range of room temperature to 85°C to fully react the alkoxysilane and volatilize the contained solvent. After that, the coating is further left to stand for 24 hours in an environment of a temperature of 85°C and a relative humidity of 85% to perform post-curing and complete the reaction. Finally, the coating is peeled off from the fluorine-treated substrate to obtain the light absorber of Example 1. The light absorber can be used as an optical filter when it is used only in a manner in which it performs its function.

[0252] (Measurement of transmission and reflection spectra of light absorbers)

[0253] Using an ultraviolet-visible-near-infrared spectrophotometer V-770 manufactured by JASCO Corporation with an accessory for measuring transmitted light, the transmission spectrum of the light absorber of Example 1 at incident angles of 0°, 40°, 50°, 60°, and 70° was measured. Unless otherwise specified, the measurement of the transmission spectrum was performed at a temperature of the surrounding environment of the measured object set to 22°C to 25°C. In addition, in the ultraviolet-visible-near-infrared spectrophotometer V-770, the accessory was replaced with a measurement accessory for reflected light, and the reflection spectrum of the light absorber of Example 1 at incident angles of 5°, 40°, 50°, 60°, and 70° was measured. Unless otherwise specified, the measurement of the transmission spectrum was performed at a temperature of the surrounding environment of the measured object set to 22°C to 25°C.

[0254] Figure 5A The transmission spectrum of the light absorber of Example 1 at each incident angle is shown. Figure 5B The reflection spectra of the light absorber of Example 1 at each incident angle are shown. Table 3 shows the characteristics of the light absorber of Example 1 at an incident angle of 0° or an incident angle of 5° corresponding to the above conditions (I) to (VII). Tables 4 and 5 show the specified characteristics at each incident angle.

[0255] (Measurement of Transmission Spectrum of Dispersion Liquid of Light-Absorbing Compound)

[0256] An appropriate amount of toluene was added to the dispersion of the light absorbing compound (G solution) of Example 1 to prepare a dispersion of the light absorbing compound for measuring optical properties. The concentration of the light absorbing compound in the dispersion of the light absorbing compound for measuring optical properties was adjusted so that the transmittance at a wavelength of 700 nm in the transmission spectrum of the dispersion of the light absorbing compound was around 20%. The dispersion of the light absorbing compound for measuring optical properties thus adjusted was placed in a quartz cuvette (manufactured by JASCO Corporation, model: J / 1 / Q / 1, optical path length: 1 mm, optical path width: 10 mm, external dimensions: length 3.5 mm, width 12.5 mm, height 45 mm, capacity: 0.400 ml). Using a UV-visible near-infrared spectrophotometer V-770 manufactured by JASCO Corporation with a transmission light measurement accessory capable of carrying a quartz cuvette, the primary transmission spectrum of the dispersion of the light absorbing compound of Example 1 at an incident angle of 0° was measured. Unless otherwise specified, the transmission spectrum is measured at a temperature of the surrounding environment of the measurement object set at 22°C to 25°C.

[0257] In addition, for a quartz cuvette filled with only toluene, the transmission spectrum at an incident angle of 0° was similarly measured. The transmission spectrum of toluene was subtracted from the transmission spectrum of the dispersion of the light-absorbing compound to calculate the secondary transmission spectrum of the dispersion of the light-absorbing compound of Example 1. Then, in the obtained transmission spectrum, the transmittance at a wavelength of 700 nm was standardized to 20%, thereby obtaining the final transmission spectrum of the dispersion of the light-absorbing compound. It should be noted that the measurement for obtaining the transmission spectrum of the dispersion was performed in the wavelength range of 300 nm to 1600 nm.

[0258] Figure 5C The transmission spectrum of the dispersion liquid of the light-absorbing compound of Example 1 is shown. Table 6 shows the characteristic values ​​obtained from the transmission spectrum of the dispersion liquid of the light-absorbing compound.

[0259] (Haze measurement)

[0260] The haze of the light absorber of Example 1 was measured using a haze meter (manufactured by Murakami Color Research Laboratory, product name: HM-65L2) in accordance with Japanese Industrial Standard (JIS) K 7136: 2000. Table 3 shows the haze value of the light absorber of Example 1 (0.13%).

[0261] (Thickness measurement)

[0262] The thickness of the light absorber of Example 1 was measured using a laser displacement meter LK-H008 manufactured by KEYENCE Corporation. Table 3 shows the thickness of the light absorber of Example 1 (192 μm).

[0263] <Example 2>

[0264] 4.500 g of copper acetate monohydrate was mixed with 240 g of tetrahydrofuran (THF) and stirred for 3 hours to obtain a copper acetate solution. Then, 1.73 g of Plysurf A208N (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a phosphate compound was added to the obtained copper acetate solution and stirred for 30 minutes to obtain liquid A. 40 g of THF was added to 0.572 g of phenylphosphonic acid and stirred for 30 minutes to obtain liquid B. 40 g of THF was added to 3.431 g of 4-bromophenylphosphonic acid and stirred for 30 minutes to obtain liquid C. 40 g of THF was added to 0.410 g of ethylphosphonic acid and stirred for 30 minutes to obtain liquid D. To the mixed solution obtained by mixing solution A, solution B, solution C and solution D, 6.93 g of methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-13) and 2.27 g of tetraethoxysilane (special grade manufactured by KISHIDA CHEMICAL Co., Ltd.) were further added, and the mixture was further stirred for 1 minute to obtain solution E. Next, 120 g of toluene was added to the solution E, and the mixture was stirred at room temperature for 1 minute to obtain solution F. The solution F was placed in a flask, and while being heated with an oil bath (manufactured by Tokyo Rikaki Co., Ltd., model: OSB-2100), a desolvation treatment was performed using a rotary evaporator (manufactured by Tokyo Rikaki Co., Ltd., model: N-1110SF). The set temperature of the oil bath was adjusted to 105°C. Thereafter, the desolvation-treated liquid was taken out from the flask. In this way, the light-absorbing compound of Example 2 containing phosphonic acid and copper components and a dispersion (G solution) of the light-absorbing compound of Example 2 were obtained.

[0265] Table 1 shows the raw materials and the amounts of raw materials added in the preparation of the light absorbing compound of Example 2 and the dispersion of the light absorbing compound of Example 2. Table 2 shows the ratio of the content of phosphonic acid, copper component, and phosphate ester contained in the dispersion of the light absorbing compound on an amount basis or a mass basis. Here, it should be noted that the dispersion of the light absorbing compound of Example 2 contains the light absorbing compound contained in the light absorber, but does not contain a curable resin and a curing catalyst.

[0266] 8.98 g of a silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300), 0.16 g of a catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., product name: CAT-AC), 6.96 g of methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-13) as a trifunctional alkoxysilane, 4.05 g of tetraethoxysilane (special grade manufactured by KISHIDA CHEMICAL Co., Ltd.) as a tetrafunctional alkoxysilane, and 4.07 g of dimethyldiethoxysilane (DMDES) (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-22) as a difunctional alkoxysilane were mixed and stirred for 30 minutes to obtain a liquid curable resin H of Example 2 that functions as a binder or a matrix resin. Next, the liquid G of Example 2, which is a dispersion containing a light-absorbing compound, was mixed with the curable resin H liquid and stirred for 30 minutes to obtain a light-absorbing composition of Example 2.

[0267] Table 1 shows the raw materials of the curable resin (matrix or binder), the curing catalyst, and the alkoxysilane used in the preparation of the light-absorbing composition of Example 2, and the amounts of the raw materials added.

[0268] The light absorbing composition I of Example 2 is applied to a range of 80 mm × 80 mm in the center of one main surface of a borosilicate glass (manufactured by SCHOTT, product name: D263 T eco) having a size of 130 mm × 100 mm × 0.70 mm using a dispenser to form a coating film. After the obtained coating film is fully dried at room temperature, it is placed in an oven and fully heated in the range of room temperature to 85°C to fully react the alkoxysilane and volatilize the contained solvent. Thereafter, it is further allowed to stand for 24 hours in an environment of a temperature of 85°C and a relative humidity of 85% for post-curing to complete the reaction. The light absorber of Example 2 is integrated on the main surface of the transparent glass. The light absorber formed on the glass substrate of Example 2 can be used as an optical filter when it is used only in a manner in which it performs its function.

[0269] The transmission spectrum, reflection spectrum, haze value, and thickness of the light absorber formed on the glass substrate of Example 2, and the transmission spectrum of the dispersion of the light absorbing compound of Example 2 were measured in the same manner as in Example 1. In Example 2, the transmission spectrum, reflection spectrum, and haze value of the light absorber were measured for the laminate of the glass substrate and the light absorber.

[0270] Figure 6The transmission spectra of the light absorber formed on the glass substrate of Example 2 at various incident angles are shown. Table 3 shows the characteristics of the light absorber formed on the glass substrate of Example 2 at an incident angle of 0° or an incident angle of 5° corresponding to the above-mentioned conditions (I) to (VII). Tables 4 and 5 show the specified characteristics of the light absorber formed on the glass substrate of Example 2 at various incident angles. Table 3 shows the haze value (0.13%) of the light absorber formed on the glass substrate of Example 2 and the thickness (182μm) of the light absorber of Example 2.

[0271] <Example 3>

[0272] The light absorbing compound, the dispersion of the light absorbing compound, the light absorbing composition, and the light absorber formed on the glass substrate of Example 3 were prepared by the same method and conditions as in Example 2, except that the raw materials and the addition amounts of the raw materials were adjusted as shown in Table 1. The transmission spectrum, reflection spectrum, haze value, thickness of the light absorber formed on the glass substrate of Example 3, and the transmission spectrum of the dispersion of the light absorbing compound of Example 3 were measured by the same method and conditions as in Example 1.

[0273] Figure 7 The transmission spectrum of the light absorber of Example 3 at each incident angle is shown. Table 3 shows the characteristics of the light absorber formed on the glass substrate of Example 3 at an incident angle of 0° or an incident angle of 5° corresponding to the above conditions (I) to (VII). Tables 4 and 5 show the specified characteristics of the light absorber formed on the glass substrate of Example 3 at each incident angle. Table 3 shows the haze value (0.12%) of the light absorber formed on the glass substrate of Example 3 and the thickness (180μm) of the light absorber of Example 3.

[0274] <Example 4>

[0275] The light absorbing compound, dispersion of the light absorbing compound, light absorbing composition, and light absorber formed on a glass substrate of Example 4 were prepared by the same method and conditions as in Example 2 except that the raw materials and the addition amounts of the raw materials were adjusted as shown in Table 1. The transmission spectrum, reflection spectrum, haze value, thickness of the light absorber formed on a glass substrate of Example 4, and the transmission spectrum of the dispersion of the light absorbing compound of Example 4 were measured by the same method and conditions as in Example 1.

[0276] Fig. 8A The transmission spectrum of the light absorber formed on the glass substrate of Example 4 at each incident angle is shown. Figure 8BThe transmission spectrum of the dispersion of the light absorbing compound of Example 4 is shown. Table 3 shows the characteristics of the light absorber formed on the glass substrate of Example 4 at an incident angle of 0° or an incident angle of 5° corresponding to the above conditions (I) to (VII). Tables 4 and 5 show the specified characteristics of the light absorber formed on the glass substrate of Example 4 at each incident angle. Table 6 shows the characteristic values ​​obtained from the transmission spectrum of the dispersion of the light absorbing compound. Table 3 shows the haze value (0.08%) of the light absorber formed on the glass substrate of Example 4 and the thickness (171μm) of the light absorber of Example 4.

[0277] <Examples 5 to 12>

[0278] The light absorbing compounds, dispersions of the light absorbing compounds, light absorbing compositions, and light absorbers formed on glass substrates of Examples 5 to 12 were prepared by the same method and conditions as in Example 1, except that the raw materials and the addition amounts of the raw materials were adjusted as shown in Table 1. The transmission spectra, reflection spectra, haze values, and thicknesses of the light absorbers formed on glass substrates of Examples 5 to 12, and the transmission spectra of the dispersions of the light absorbing compounds of Examples 5, 8, and 10 were measured by the same method and conditions as in Example 1.

[0279] Fig.9A , Fig. 9B and Fig. 9C The transmission spectrum of the light absorber of Example 5 at each incident angle, the reflection spectrum of the light absorber at each incident angle, and the transmission spectrum of the dispersion liquid of the light absorbing compound are shown respectively. Fig.10 The transmission spectrum of the light absorber of Example 6 at each incident angle is shown. Fig.11 The transmission spectrum of the light absorber of Example 7 at each incident angle is shown. Fig. 12A , Fig. 12B and Fig. 12C The transmission spectrum of the light absorber of Example 8 at each incident angle, the reflection spectrum of the light absorber at each incident angle, and the transmission spectrum of the dispersion liquid of the light absorbing compound are shown respectively. Fig.13 The transmission spectrum of the light absorber of Example 9 at an incident angle of 0° is shown. Fig.14A and Fig. 14B The transmission spectrum of the light absorber of Example 10 at an incident angle of 0° and the transmission spectrum of the dispersion liquid of the light absorbing compound are respectively shown. Fig.15 The transmission spectrum of the light absorber of Example 11 at an incident angle of 0° is shown. Fig.16 The transmission spectrum of the light absorber of Example 12 at an incident angle of 0° is shown.

[0280] Table 3 shows the characteristics of the light absorbers of Examples 5 to 12 at an incident angle of 0° or an incident angle of 5° corresponding to the conditions of (I) to (VII) above. Tables 4 and 5 show the specified characteristics of the light absorbers of Examples 5 to 12 at each incident angle. Table 6 shows the characteristic values ​​obtained from the transmission spectra of the dispersions of the light absorbing compounds of Examples 5, 8 and 10. Table 3 shows the haze value and thickness (171 μm) of the light absorbers of Examples 5 to 12.

[0281] <Example 13>

[0282] The light absorbing compound, dispersion of the light absorbing compound, light absorbing composition, and light absorber of Example 13 were prepared by the same method and conditions as in Example 1 except that the raw materials and the amounts of the raw materials added were adjusted as shown in Table 1.

[0283] An anti-reflection film is formed on both main surfaces of the light absorber of Example 13 to obtain the filter of Example 13. An appropriate amount of methyltriethoxysilane (MTES), tetraethoxysilane (TEOS), water for hydrolysis and ethanol are mixed and stirred to prepare an anti-reflection film coating agent as a precursor of the anti-reflection film. The anti-reflection film coating agent is applied to both main surfaces of the light absorber of Example 13. The anti-reflection film coating agent is applied to the light absorber side by side. After the anti-reflection film coating agent is applied to one main surface and left to stand, after about 1 minute, after confirming that the surface coated with the anti-reflection film coating agent is dry, the anti-reflection film coating agent is applied to the other main surface in the same manner. Thereafter, the light absorber is placed in a constant temperature bath and heated for 1 hour in an atmosphere of 85°C to evaporate and remove excess solvents and by-products, and an anti-reflection film is provided on both main surfaces of the light absorber. The anti-reflection film is porous, and the film thickness of the anti-reflection film on both main surfaces is about 180nm. In this way, the optical filter of Example 13 having an antireflection film was obtained.

[0284] Fig.17A and 17B The transmission spectrum of the filter of Example 13 at each incident angle and the reflection spectrum of the filter of Example 13 at each incident angle are shown respectively. These transmission spectra and reflection spectra are obtained by the same method and conditions as in Example 1. Table 3 shows the characteristic values ​​of the filter of Example 13 at an incident angle of 0° or an incident angle of 5° corresponding to the above-mentioned conditions (I) to (VII). Tables 4 and 5 show the specified characteristics of the filter of Example 13 at each incident angle. Table 6 shows the characteristic values ​​obtained from the transmission spectrum of the dispersion of the light-absorbing compound of Example 13. The transmission spectrum of the dispersion of the light-absorbing compound of Example 13 is obtained by the same method and conditions as in Example 1. Table 3 shows the haze value of the filter of Example 13 and the thickness of the light absorber.

[0285] <Comparative Examples 1 and 2>

[0286] The light absorbing compounds, dispersions of the light absorbing compounds, light absorbing compositions, and light absorbers of Comparative Examples 1 and 2 were prepared by the same method and conditions as in Example 1 except that the raw materials and the addition amounts of the raw materials were adjusted as shown in Table 1. In Comparative Example 1, the ratio of the content of the arylphosphonic acid to the content of the alkylphosphonic acid was 9.414 on an amount basis, and in Comparative Example 2, the ratio of the content of the arylphosphonic acid to the content of the alkylphosphonic acid was 12.983 on an amount basis. The transmission spectra, reflection spectra, haze values, and thicknesses of the light absorbers of Comparative Examples 1 and 2 were measured by the same method and conditions as in Example 1.

[0287] Fig.18 and Fig.19 The transmission spectra of the light absorbers of Comparative Examples 1 and 2 at an incident angle of 0° are shown respectively. Table 3 shows the characteristic values ​​of the filter of Example 13 at an incident angle of 0° or an incident angle of 5° corresponding to the conditions of (I) to (VII) above. Table 6 shows the haze values ​​and thicknesses of the light absorbers of Comparative Examples 1 and 2. The haze values ​​of the light absorbers of Comparative Examples 1 and 2 are 0.38 and 7.75, respectively.

[0288] <Reference Examples 1 and 2>

[0289] The light absorbing compounds, dispersions of light absorbing compounds, light absorbing compositions, and light absorbers of Reference Examples 1 and 2 were prepared by the same method and conditions as in Example 1, except that the raw materials and the amounts of raw materials added were adjusted as shown in Table 1. In Reference Examples 1 and 2, the ratio of the content of the arylphosphonic acid to the content of the alkylphosphonic acid was 1.620 on an amount basis. The transmission spectra, reflection spectra, haze values, and thicknesses of the light absorbers of Reference Examples 1 and 2 were measured by the same method and conditions as in Example 1.

[0290] Fig. 20A and Fig.21A The transmission spectra of the light absorbers of Reference Examples 1 and 2 at an incident angle of 0° are shown respectively. Fig. 20B and Fig.21BThe transmission spectra of the light absorbers of Reference Examples 1 and 2 at an incident angle of 0° in the wavelength range of 400nm to 500nm and the rate of change of transmittance with respect to wavelength dT / dλ are shown respectively. In the transmission spectra of the light absorbers of Reference Examples 1 and 2, steps are confirmed in the wavelength range of 420nm to 480nm, and regarding the rate of change of transmittance with respect to wavelength, in the wavelength range of 420nm to 480nm, the minimum value of 0.1 [% / nm] or less exists in the wavelength range of 440nm to 460nm, and the difference between the maximum value and the minimum value of the rate of change of transmittance with respect to wavelength in the wavelength range of 420nm to 480nm exceeds 0.4 [% / nm].

[0291] Table 3 shows the characteristic values ​​of the optical filters of Reference Examples 1 and 2 at an incident angle of 0° or an incident angle of 5° corresponding to the conditions of (I) to (VII) above. In addition, Table 3 shows the haze values ​​and thicknesses of the light absorbers of Reference Examples 1 and 2. The haze values ​​of Reference Examples 1 and 2 were 0.14 and 0.16, respectively.

[0292]

[0293]

[0294]

[0295]

[0296] [Table 5]

[0297]

[0298] [Table 6]

[0299]

Claims

1. A light absorber having a transmission spectrum satisfying the following conditions (I), (II), (III), (IV) and (V) at an incident angle of 0°, With a haze of less than 0.20%, (I) The average transmittance in the wavelength range of 460 nm to 600 nm is 75% or more; (II) The short-wavelength side cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 350 nm to 450 nm is 390 nm to 450 nm; (III) The long-wavelength side cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 600 nm to 700 nm is 600 nm to 680 nm; (IV) The average transmittance in the wavelength range of 300 nm to 380 nm is 1.2% or less; (V) The average value of the transmittance in the wavelength range of 750 nm to 1100 nm is 1.2% or less.

2. The light absorber according to claim 1, comprising: Copper content; a first phosphonic acid represented by the following formula (a); and The second phosphonic acid represented by the following formula (b), In the following formula (a), R1 is an alkyl group or a halogenated alkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom, In the following formula (b), R2 is an aryl group or a modified aryl group in which at least one hydrogen atom in the aryl group is substituted with a halogen atom, a nitro group or a hydroxyl group, 3. The light absorber according to claim 2, wherein: The ratio of the content of the second phosphonic acid to the content of the first phosphonic acid is 1.8 to 9 on an amount basis.

4. The light absorber according to claim 3, wherein: The ratio of the sum of the content of the first phosphonic acid and the content of the second phosphonic acid to the content of the copper component is 0.3 to 3 on an amount basis.

5. The light absorber according to claim 4, wherein: The ratio of the content of the first phosphonic acid to the content of the copper component is 0.05 to 0.8 on a mass basis. The ratio of the content of the second phosphonic acid to the content of the copper component is 0.2 to 1.5 on an amount basis.

6. A light absorbing compound comprising: a first light absorbing compound comprising a copper component and a first phosphonic acid represented by the following formula (a); and The second light absorbing compound comprises a copper component and a second phosphonic acid represented by the following formula (b), In the following formula (a), R1 is an alkyl group or a halogenated alkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom, In the following formula (b), R2 is an aryl group or a modified aryl group in which at least one hydrogen atom in the aryl group is substituted with a halogen atom, a nitro group or a hydroxyl group, The transmission spectrum of the dispersion of the light absorbing compound satisfies the following conditions (i), (ii), (iii) and (iv), (i) The average transmittance in the wavelength range of 460 nm to 600 nm is 85% or more; (ii) the short-wavelength side cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 350 nm to 450 nm is 380 nm to 420 nm; (iii) the long-wavelength side cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 600 nm to 700 nm is 600 nm to 650 nm; (iv) the average transmittance in the wavelength range of 725 nm to 1000 nm is 5% to 20%, 7. The light-absorbing compound according to claim 6, wherein The ratio of the content of the second phosphonic acid to the content of the first phosphonic acid is 1.8 to 9 on an amount basis.

8. The light-absorbing compound according to claim 7, wherein The ratio of the sum of the content of the first phosphonic acid and the content of the second phosphonic acid to the content of the copper component is 0.3 to 3 on an amount basis.

9. The light-absorbing compound according to claim 8, wherein The ratio of the content of the first phosphonic acid to the content of the copper component is 0.05 to 0.8 on a mass basis. The ratio of the content of the second phosphonic acid to the content of the copper component is 0.2 to 1.5 on an amount basis.

10. A dispersion of a light absorbing compound, characterized in that: It contains: Light absorbing compounds; Solvents; and Alkoxysilane or a hydrolyzate of alkoxysilane, The light absorbing compound comprises: a first light absorbing compound comprising a copper component and a first phosphonic acid represented by the following formula (a); and a second light absorbing compound comprising a copper component and a second phosphonic acid represented by the following formula (b), In the following formula (a), R1 is an alkyl group or a halogenated alkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom, In the following formula (b), R2 is an aryl group or a modified aryl group in which at least one hydrogen atom in the aryl group is substituted with a halogen atom, a nitro group or a hydroxyl group, 11. The dispersion of the light absorbing compound according to claim 10, wherein The ratio of the content of the second phosphonic acid to the content of the first phosphonic acid is 1.8 to 9 on an amount basis.

12. The dispersion of a light absorbing compound according to claim 10, which satisfies the following conditions (i), (ii), (iii) and (iv), (i) The average transmittance in the wavelength range of 460 nm to 600 nm is 85% or more; (ii) the short-wavelength side cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 350 nm to 450 nm is 380 nm to 420 nm; (iii) the long-wavelength side cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 600 nm to 700 nm is 600 nm to 650 nm; (iv) The average transmittance in the wavelength range of 725 nm to 1000 nm is 5% to 20%.

13. The dispersion of a light-absorbing compound according to claim 10, which does not substantially contain a curable resin.

14. A light-absorbing composition comprising: A first light absorbing compound comprising a copper component and a first phosphonic acid represented by the following formula (a); a second light absorbing compound comprising a copper component and a second phosphonic acid represented by the following formula (b); Solvents; and Binder, In the following formula (a), R1 is an alkyl group or a halogenated alkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom, In the following formula (b), R2 is an aryl group or a modified aryl group in which at least one hydrogen atom in the aryl group is substituted with a halogen atom, a nitro group or a hydroxyl group, The ratio of the content of the second phosphonic acid to the content of the first phosphonic acid is 1.8 to 9 on an amount basis.

15. The light-absorbing composition according to claim 14, wherein The ratio of the sum of the content of the first phosphonic acid and the content of the second phosphonic acid to the content of the copper component is 0.3 to 3 on an amount basis.

16. The light-absorbing composition according to claim 15, wherein The ratio of the content of the first phosphonic acid to the content of the copper component is 0.05 to 0.8 on a mass basis. The ratio of the content of the second phosphonic acid to the content of the copper component is 0.2 to 1.5 on an amount basis.

17. The light-absorbing composition according to any one of claims 14 to 16, wherein The light absorber which is a cured product of the light absorbing composition has a transmission spectrum satisfying the following conditions (I), (II), (III), (IV) and (V) at an incident angle of 0°, With a haze of less than 0.20%, (I) The average transmittance in the wavelength range of 460 nm to 600 nm is 75% or more; (II) The short-wavelength side cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 350 nm to 450 nm is 390 nm to 450 nm; (III) The long-wavelength side cutoff wavelength at which the transmittance reaches 50% in the wavelength range of 600 nm to 700 nm is 600 nm to 680 nm; (IV) The average transmittance in the wavelength range of 300 nm to 380 nm is 1.2% or less; (V) The average value of the transmittance in the wavelength range of 750 nm to 1100 nm is 1.2% or less. 18 . An optical filter comprising the light absorber according to claim 1 .

19. A photoelectric conversion element comprising a light receiving surface and the light absorber according to any one of claims 1 to 5, The light receiving surface and the light absorber are arranged in this order.

20. An ambient light sensor comprising the optical filter according to claim 18.

21. An imaging device comprising the optical filter according to claim 18.

Images