WO2022044286A1

WO2022044286A1 - Near-infrared cut filter and imaging device provided with same

Info

Publication number: WO2022044286A1
Application number: PCT/JP2020/032735
Authority: WO
Inventors: 武志山▲崎▼
Original assignee: Hoya株式会社
Priority date: 2020-08-28
Filing date: 2020-08-28
Publication date: 2022-03-03
Also published as: TW202208892A

Abstract

Provided is a near-infrared cut filter that is much less dependent of the angle of incidence, and has excellent oblique incidence characteristics.　The near-infrared cut filter comprises: a transparent substrate that is made of a fluorophosphate glass or a phosphate glass, and that has an average transmittance of at most 3% in the wavelength range of 800-950 nm; and a resin layer that is formed on at least one main surface of the transparent substrate, and that absorbs light having a specific wavelength.

Description

Near-infrared cut filter and image pickup device equipped with it

The present invention relates to a near-infrared cut filter arranged in front of a solid-state image sensor and used for correcting the visual sensitivity of the solid-state image sensor, and an image pickup device including the same.

In recent years, image pickup devices with built-in solid-state image sensors such as CCD and CMOS have been used in digital cameras, information mobile terminal devices, and the like. In such an image pickup device, since the solid-state image sensor has spectral sensitivity from the near-ultraviolet region to the near-infrared region, the near-infrared portion of the incident light is cut and corrected so as to be close to the human visual sensitivity. It is equipped with a near-infrared cut filter. Such a near-infrared cut filter is arranged in the optical path to the solid-state image sensor, but in order to reduce the size of the entire image pickup device, a near-infrared cut filter having a configuration that doubles as a cover glass of the image pickup device is also practical. Provided (for example, Patent Document 1).

FIG. 17 is an example of the configuration of the near-infrared cut filter (conventional example) described in Patent Document 1. As shown in FIG. 17, the near-infrared cut filter described in Patent Document 1 is formed on one main surface of the transparent base material 13 and the transparent base material 13, and is light in the near-infrared wavelength region and the ultraviolet wavelength region. It is provided with an absorption layer 11 that absorbs light, and a reflection layer 12 that is formed on the other main surface of the transparent substrate 13 and controls the transmission and shielding of light in a specific wavelength region. The reflective layer 12 is made of a dielectric multilayer film having a thickness of 2 to 10 μm, in which a low refractive index dielectric film (low dielectric film) and a high refractive index dielectric film (high refractive index film) are alternately laminated. By being configured so that the spectral transmittance of the reflective layer 12 satisfies a predetermined requirement, the near infrared rays have spectral characteristics close to the relative visibility curve, especially on the long wavelength side, and have little dependence on the incident angle. A cut filter is realized.

Japanese Patent No. 6119920

However, since the near-infrared cut filter described in Patent Document 1 includes a reflective layer 12 composed of a relatively thick (thickness 2 to 10 μm) dielectric multilayer film, light is obliquely emitted to the reflective layer 12. When incident, the optical path length becomes long, and there is a problem that a phase shift occurs.

FIG. 18 is a diagram showing a spectral transmittance curve of the reflective layer 12 of the near-infrared cut filter of FIG. 17, a spectral transmittance curve (solid line) when the incident angle is 0 °, and a spectrum when the incident angle is 30 °. The transmittance curve (broken line) is shown. Further, FIG. 19 is a diagram showing a spectral transmittance curve of the near-infrared cut filter of FIG. 17, a spectral transmittance curve (solid line) when the incident angle is 0 °, and a spectral transmittance when the incident angle is 30 °. A curve (broken line) is shown.

As shown in FIG. 18, when light having an incident angle of 30 ° is incident on the reflective layer 12, the spectral transmittance curve shifts to the short wavelength side due to the influence of the phase shift (P1 part in FIG. 18), or the spectral transmittance. There is a problem that ripples occur in the curve (P2 part in FIG. 18). When a wavelength shift occurs in the spectral transmittance curve of the reflective layer 12, a wavelength shift also occurs in the spectral transmittance curve of the near-infrared cut filter (P3 portion in FIG. 19), and the color reproducibility of the solid-state imaging device is reduced. There is a risk. Further, when ripples occur in the spectral transmittance curve of the reflective layer 12, ripples also occur in the spectral transmittance curve of the near-infrared cut filter (P4 part in FIG. 19), and a kind of ghost is observed on the solid-state image sensor. There was a risk that it would end up. Therefore, there has been a demand for a near-infrared cut filter having excellent oblique incident characteristics that does not cause wavelength shift or ripple even with oblique incident light.

The present invention has been made in view of such circumstances, and an object thereof is a near-infrared cut filter having extremely little dependence on an incident angle and having excellent oblique incident characteristics, and such a near-infrared cut filter. It is to provide the image pickup apparatus provided with.

As a result of diligent studies by the present inventor in order to achieve the above object, attention was paid particularly to the wavelength range of 800 to 950 nm in the spectral transmittance curve of the transparent substrate made of fluoride-based glass or phosphate-based glass. If a cut filter with a small average transmittance in the wavelength range of 800 to 950 nm is used, a cut filter that selectively transmits light in the visible light region can be used without using the reflective film used in the conventional near-infrared cut filter. Found that it can be manufactured. The present invention has been made based on such findings.

That is, the near-infrared cut filter of the present invention is made of a fluoride-based glass or a phosphate-based glass, and has a transparent substrate having an average transmittance of 3% or less in the wavelength range of 800 to 950 nm and a transparent substrate. It is characterized by comprising a resin layer formed on at least one main surface and absorbing light having a specific wavelength.

With such a configuration, since the reflection layer composed of the conventional dielectric multilayer film is unnecessary (that is, because the reflection layer is not provided), the light is obliquely incident on the near-infrared cut filter. Even if this is the case, the optical path length is unlikely to change, and the occurrence of phase shift is suppressed. Therefore, wavelength shift and ripple hardly occur in the spectral transmittance curve of the near-infrared cut filter.

Further, it is preferable that the half-value wavelength on the short wavelength side of the transmittance curve of the transparent substrate is 335 to 400 nm, and the half-value wavelength on the long wavelength side is 590 to 630 nm.

Further, the transparent substrate preferably has an average transmittance of 18% or less in the wavelength range of 650 to 720 nm.

Further, the transparent substrate preferably has an average transmittance of 10% or less in the wavelength range of 720 to 750 nm.

Further, the resin layer can contain a transparent resin and a dye uniformly dispersed in the transparent resin. Further, in this case, the dye preferably contains an ultraviolet absorbing dye having a maximum absorption wavelength of 340 to 400 nm. Further, the dye preferably contains a first near-infrared absorption dye having a maximum absorption wavelength of 650 to 760 nm. Further, in this case, the dye preferably contains a second near-infrared absorption dye having a maximum absorption wavelength of 800 to 1200 nm.

Further, the resin layer can contain one or more selected from Ti atom, Zr atom and Al atom together with Si atom.

Further, a bonding layer that enhances the adhesion between the transparent substrate and the resin layer can be provided between the transparent substrate and the resin layer. Further, in this case, it is preferable that the bonding layer has a single-layer structure containing one or more selected from Ti atom, Zr atom and Al atom together with Si atom. Further, in this case, the ratio of the total number of atoms of Ti atom, Zr atom and Al atom to the total number of Si atom, Ti atom, Zr atom and Al atom in the bonding layer exceeds 0 atomic% and 33.3 atomic% or less. Is preferable.

Further, a first antireflection film can be provided on the resin layer, and a second antireflection film can be provided on the other main surface of the transparent base material. Further, in this case, it is preferable that the half-value wavelength on the short wavelength side of the transmittance curve is 385 to 430 nm and the half-value wavelength on the long wavelength side is 590 to 630 nm. Further, in this case, it is preferable that the first antireflection film and the second antireflection film are each composed of a dielectric multilayer film having a thickness of 500 nm or less. Further, in this case, the number of dielectric multilayer films is preferably 10 or less.

The dielectric multilayer film is a low refractive index film made of a material having a refractive index of 1.1 to 1.5 and a high refractive index film made of a material having a refractive index of 2.0 to 2.5. And are preferably formed by being alternately laminated.

The dielectric multilayer film is a low refractive index film made of a material having a refractive index of 1.1 to 1.3 and a high refractive index film made of a material having a refractive index of 1.4 to 1.6. And are preferably formed by being alternately laminated.

Further, the thickness of the transparent base material is preferably 0.01 to 1.5 mm.

From another point of view, the image pickup device of the present invention is characterized by including a solid-state image pickup device and any of the above-mentioned near-infrared cut filters. Further, in this case, the near-infrared cut filter is arranged immediately in front of the solid-state image sensor, and can be configured to also serve as a cover glass.

As described above, according to the present invention, a near-infrared cut filter having extremely little dependence on the incident angle and having excellent oblique incident characteristics is realized. Further, an image pickup device equipped with such a near-infrared cut filter and having excellent color reproducibility is realized.

FIG. 1 is a diagram illustrating a configuration of a near-infrared cut filter according to a first embodiment of the present invention. FIG. 2 is a vertical sectional view illustrating the configuration of an image pickup apparatus equipped with a near-infrared cut filter according to the first embodiment of the present invention. FIG. 3 is a diagram showing a spectral transmittance curve of a glass substrate used in the near-infrared cut filter according to the first embodiment (Example 1) of the present invention. FIG. 4 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the first embodiment (Example 1) of the present invention. FIG. 5 is a diagram showing a spectral transmittance curve of a near-infrared cut filter according to a first embodiment (Example 2) of the present invention and a glass substrate used in the near-infrared cut filter. FIG. 6 is a diagram showing a spectral transmittance curve of a near-infrared cut filter according to a first embodiment (Example 3) of the present invention and a glass substrate used in the near-infrared cut filter. FIG. 7 is a diagram showing a spectral transmittance curve of a near-infrared cut filter according to a first embodiment (Example 4) of the present invention and a glass substrate used in the near-infrared cut filter. FIG. 8 is a diagram showing a spectral transmittance curve of a near-infrared cut filter according to a first embodiment (Example 5) of the present invention and a glass substrate used in the near-infrared cut filter. FIG. 9 is a diagram showing a spectral transmittance curve of a near-infrared cut filter according to a comparative example of the present invention and a glass substrate used in the near-infrared cut filter. FIG. 10 is a vertical cross-sectional view illustrating the configuration of the near-infrared cut filter according to the second embodiment of the present invention. FIG. 11 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 6) of the present invention. FIG. 12 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 7) of the present invention. FIG. 13 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 8) of the present invention. FIG. 14 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 9) of the present invention. FIG. 15 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 10) of the present invention. FIG. 16 is a vertical cross-sectional view illustrating the configuration of the near-infrared cut filter according to the third embodiment (Example 11) of the present invention. FIG. 17 is a vertical sectional view showing the configuration of a conventional near-infrared cut filter. FIG. 18 is a diagram showing a spectral transmittance curve of a reflective layer used in a conventional near-infrared cut filter. FIG. 19 is a diagram showing a spectral transmittance curve of a conventional near-infrared cut filter.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated.

(First Embodiment)
1A and 1B are views for explaining the configuration of the near-infrared cut filter 100 according to the first embodiment of the present invention, FIG. 1A is a plan view, and FIG. 1B is a vertical sectional view. be. Further, FIG. 2 is a vertical cross-sectional view illustrating the configuration of the image pickup apparatus 1 in which the opening of the package 300 of the solid-state image pickup device 200 is sealed by the near-infrared cut filter 100 of the present embodiment. As shown in FIGS. 1 and 2, the near-infrared cut filter 100 of the present embodiment is attached to the front surface of the package 300 for accommodating the solid-state image sensor 200 to protect the solid-state image sensor 200 and the solid-state image sensor 200. It is an optical element used for visual sensitivity correction.

As shown in FIG. 1, the near-infrared cut filter 100 of the present embodiment has a rectangular plate-like appearance (for example, 6 mm (horizontal direction) × 5 mm (longitudinal direction)), and has a glass base material 101 (transparent group). The material) and the resin layer 102 formed on one main surface of the glass base material 101 (the upper surface in FIG. 1B).

[Glass substrate]
The glass base material 101 of the present embodiment is an absorbent glass substrate made of phosphate-based glass or fluoride-based glass. The thickness of the glass base material 101 of the present embodiment is not particularly limited, but is preferably in the range of 0.01 to 1.5 mm, more preferably 0.01 to 0.70 mm, from the viewpoint of reducing the size and weight. Those having a thickness of 0.01 to 0.30 mm are more preferable.

The phosphate-based glass in the present embodiment is a glass containing P and O as essential components and other optional components, and a glass containing CuO is particularly preferable. Since the phosphate-based glass contains CuO, near-infrared light can be absorbed more effectively. Examples of other optional components of the phosphate-based glass include Ca, Mg, Sr, Ba, Li, Na, K, and Cs.

As a specific example of phosphate-based glass,
P ₂ O ₅ : More than 0% by mass and 70% by mass or less,
Al ₂ O ₃ : 0-40% by mass,
BaO: 0-40% by mass,
CuO: 0-40% by mass
Is preferable.

again,
P ₂ O ₅ : 20-60% by mass,
Al ₂ O ₃ : 0 to 10% by mass,
BaO: 0 to 10% by mass,
CuO: 0 to 10% by mass
Is more preferable.

again,
P ₂ O ₅ : 20-60% by mass,
Al ₂ O ₃ : 1 to 10% by mass,
BaO: 1-10% by mass,
CuO: 1-10% by mass
It is more preferable to include.

Further, the fluoride-based glass in the present embodiment is a glass containing P, O, F as essential components and other optional components, and a glass containing CuO is particularly preferable. Since the futurate-based glass contains CuO, near-infrared light can be absorbed more effectively. Examples of other optional components of the phosphate-based glass include Ca, Mg, Sr, Ba, Li, Na, K, Cs and the like.

Further, as the futurate-based glass, one containing BaO is preferably used. By containing 0% or more of BaO, the devitrification resistance and the meltability of the glass can be improved. If it is more than 10%, devitrification is likely to occur, so 0 to 10% is preferable. The BaO content is more preferably 1 to 10%, even more preferably 1 to 5%.

Further, as the futurate-based glass, one containing Al ₂ O ₃ is preferably used. By containing 0% or more of Al ₂ O ₃ , the stability and chemical durability of the glass can be improved. If it is more than 10%, devitrification is likely to occur, so 0 to 10% is preferable. Further, the content of Al ₂ O ₃ is more preferably 1 to 10%, further preferably 1 to 5%.

Further, as the _futurate _- based glass, one containing Y2O3 is preferably used. By containing 0% or _more of Y2O3 _, the refractive index can be increased while maintaining the thermal stability. If it is more than 10%, devitrification is likely to occur, and the glass transition temperature and the yield point temperature increase. Therefore, 0 to 10% is preferable. Further, the content of Y ₂ O ₃ is more preferably 1 to 10%, further preferably 1 to 5%.

Further, as the futurate-based glass, one containing BaCl ₂ is preferably used. By introducing an appropriate amount of Cl into the glass by BaCl ₂ , the difference between the crystallization start temperature (Tx) and the glass transition temperature (Tg) of the glass becomes large, and the stability of the glass against devitrification is improved. If it is more than 10%, devitrification is likely to occur, so 0 to 10% is preferable. Further, the content of BaCl ₂ is more preferably 1 to 10%, further preferably 1 to 5%.

As a specific example of futurate-based glass,
P ₂ O ₅ : More than 0% by mass and 70% by mass or less,
Al ₂ O ₃ : 0-40% by mass,
BaO: 0-40% by mass,
CuO: 0-40% by mass
It is preferable that the fluoride is contained in an amount of more than 0% by mass and 40% by mass or less.

again,
P ₂ O ₅ : 20-60% by mass,
Al ₂ O ₃ : 0 to 10% by mass,
BaO: 0-10% by mass,
CuO: 0 to 10% by mass
It is more preferable to contain 1 to 30% by mass of fluoride.

again,
P ₂ O ₅ : 20-60% by mass,
Al ₂ O ₃ : 1 to 10% by mass,
BaO: 1-10% by mass,
CuO: 1-10% by mass
It is more preferable to contain 2 to 30% by mass of fluoride.

Examples of the fluoride include one or more selected from MgF ₂ , CaF ₂ , SrF ₂ , and the like.

As a specific example of such a fluoride-based glass,
P ₂ O ₅ : 40 to 50% by mass,
Al ₂ O ₃ : 1 to 10% by mass,
BaO: 1-10% by mass,
CuO: 1-10% by mass,
MgF ₂ : 1 to 10% by mass,
CaF ₂ : 1 to 10% by mass,
SrF ₂ : 1 to 10% by mass,
Y ₂ O ₃ : 1 to 10% by mass,
BaCl ₂ : 0 to 1% by mass,
Those containing the above are particularly preferable.

Although details will be described later, the glass substrate 101 of the present embodiment is configured so that the average transmittance in the wavelength range of 800 to 950 nm is 3% or less. As described above, when the glass substrate 101 having a small average transmittance in the wavelength range of 800 to 950 nm is used, visible light is used without using the reflective film (dielectric multilayer film) used in the conventional near-infrared cut filter. A cut filter that selectively transmits light in a region can be manufactured.

Further, the glass substrate 101 preferably has an average transmittance of 10% or less, more preferably 8% or less, and further preferably 7% or less in the wavelength range of 720 to 750 nm.

Further, the glass substrate 101 preferably has a half-wavelength (UV_λ50) on the short wavelength side of the transmittance curve in the range of 335 to 400 nm, more preferably in the range of 335 to 380 nm, and more preferably in the range of 340 to 350 nm. It is more preferable to be in. Further, the glass substrate 101 preferably has a half-wavelength (NIR_λ50) on the long wavelength side of the transmittance curve in the range of 590 to 630 nm, and more preferably in the range of 610 to 624 nm. In the present specification, the half-value wavelength means the wavelength when the transmittance becomes 50%, and the half-value wavelength (UV_λ50) on the short wavelength side means the transmittance becomes 50% at the rising edge of the transmittance curve. The half-value wavelength (NIR_λ50) on the long wavelength side refers to the wavelength at which the transmittance becomes 50% at the falling edge of the transmittance curve.

Further, the glass substrate 101 preferably has an average transmittance of 18% or less, more preferably 17% or less, and further preferably 16% or less in the wavelength range of 650 to 720 nm.

[Resin layer]
The resin layer 102 of the present embodiment is a layer composed of a dye and a resin that absorb light of a specific wavelength. The resin layer 102 contains, for example, at least one of a near-infrared absorbing dye and an ultraviolet absorbing dye and a transparent resin, and it is preferable that the dye is uniformly dissolved or dispersed in the transparent resin.

As the near-infrared absorbing dye constituting the resin layer 102, conventionally known dyes can be adopted, for example, cyanine-based dyes, polymethine-based dyes, squarylium-based dyes, porphyrin-based dyes, metal dithiol complex-based dyes, and phthalocyanine-based dyes. One or more selected from dyes, diimonium dyes and inorganic oxide particles can be used, and one or more selected from squarylium dyes, cyanine dyes and phthalocyanine dyes are more preferable.

As the ultraviolet absorbing dye constituting the resin layer 102, conventionally known ones can be adopted, for example, a benzotriazole-based compound, a benzophenone-based compound, a triazine-based compound, a benzoxazinone-based compound, a cyanoacrylate-based compound, and an oxanilide-based compound. One or more selected from compounds, salicylate-based compounds, formamidine-based compounds, indol-based compounds, and azomethine-based compounds can be used, and one or more selected from benzotriazole-based compounds, benzophenone-based compounds, and triazine-based compounds are more. preferable.

As the resin constituting the resin layer 102, a conventionally known transparent resin can be adopted, and acrylic resin, epoxy resin, en-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, and polyether monkey can be used. Examples thereof include one or more selected from phon resin, polyparaphenylene resin, polyarylene ether phosphine oxide resin, polyimide resin, polyamideimide resin, polyolefin resin, cyclic olefin resin and polyester resin. As the transparent resin, a resin having a high glass transition point (Tg) is preferable from the viewpoint of transparency, solubility of the near-infrared absorbing dye in the transparent resin, and heat resistance, and therefore a thermosetting resin is preferable. Specifically, one or more selected from polyester resin, polycarbonate resin, polyether sulfone resin, polyarylate resin, polyimide resin, and epoxy resin can be used. As the polyester resin, one or more selected from polyethylene terephthalate resin and polyethylene naphthalate resin are preferable. Further, even a thermoplastic resin can be suitably used as a transparent resin by increasing the heat resistance by adjusting functional groups and the like. For example, acrylic resins, polyamide resins, polyolefin resins and the like, which can increase heat resistance by adjusting functional groups and the like, can also be used as the transparent resin.

In addition to the near-infrared absorbing dye and the transparent resin, the resin layer 102 further includes a color correction dye, a leveling agent, an antistatic agent, a heat stabilizer, a light stabilizer, and an antioxidant to the extent that the effects of the present invention are not impaired. , Dispersant, flame retardant, lubricant, plasticizer and other optional components may be contained.

In the resin layer 102, for example, a dye, a transparent resin, and an optional compounding component are dissolved or dispersed in a solvent to prepare a resin film-forming liquid, which is coated and dried, and further cured if necessary. It can be formed by. The resin film-forming liquid may contain a known surfactant such as a cationic type, an anion type, or a nonionic type.

Further, for the coating of the resin film forming liquid, one or more coating methods selected from a dip coating method, a cast coating method, a spray coating method, a spin coating method and the like can be adopted.

As described above, the resin layer 102 is a layer formed on the glass base material 101 and configured to absorb light having a specific wavelength, and the absorption wavelength is set according to the spectral transmittance characteristics of the glass base material 101. By setting (that is, selecting the optimum dye), light in the desired visible light region can be extracted.
Specifically, in the resin layer 102 of the present embodiment, an ultraviolet absorbing dye having a maximum absorption wavelength of 340 to 400 nm and a near infrared absorbing dye having a maximum absorption wavelength of 650 to 760 nm (first near infrared). Absorbent dyes) and those containing. Further, the resin layer 102 can further contain a near-infrared absorbing dye (second near-infrared absorbing dye) having a maximum absorption wavelength of 800 to 1200 nm.
The resin layer 102 of the present embodiment is formed on one main surface of the glass base material 101 (the upper surface in FIG. 1B), but is not limited to such a configuration. .. The resin layer 102 may be formed on the other main surface of the glass base material 101 (the lower surface in FIG. 1B), or may be formed on both sides of the glass base material 101. Further, the resin layer 102 does not necessarily have to be one layer, and may be composed of a plurality of layers.

The spectral transmittance curve of the near-infrared cut filter 100 on which the resin layer 102 is formed has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of 385 to 430 nm and a half-value wavelength (NIR_λ50) on the long wavelength side. ) Is 3.0% or less in the wavelength range of 590 to 630 nm and 800 to 950 nm, and the characteristics are close to those of human visual sensitivity (details will be described later).

[Image pickup device]
Next, the image pickup apparatus according to the present invention will be described. As shown in FIG. 2, the image pickup device 1 according to the present invention includes a solid-state image pickup element 200, a package 300 for accommodating the solid-state image pickup element 200, and a near-infrared cut filter 100 attached to the front surface of the package 300. ..

Examples of the solid-state image sensor 200 include image sensors such as CCD (Charge-Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor).

The solid-state image sensor 200 is arranged substantially in the center of the bottom surface of the box-shaped package 300 so that the other main surface side (lower side in FIG. 1B) of the near-infrared cut filter 100 faces the solid-state image sensor 200. Is attached to the opening of the package 300. In FIG. 2, the resin layer 102 side of the near-infrared cut filter 100 is an incident surface on which light directed toward the solid-state image sensor 200 is incident, and the other main surface side of the near-infrared cut filter 100 is an exit surface. However, the configuration is not necessarily limited to this, and the near-infrared cut filter 100 may be mounted upside down (that is, the resin layer 102 faces the solid-state image sensor 200).

Further, in the image pickup apparatus 1 of FIG. 2, the near-infrared cut filter 100 is attached to the opening of the package 300 and has a configuration that also serves as a so-called cover glass, but the configuration is not necessarily limited to such a configuration. .. For example, the image pickup device 1 may include a lens group (not shown) that guides light to the solid-state image pickup device 200. At this time, for example, the near-infrared cut filter 100 may be arranged closer to the image pickup device 1 than the lens group, and a cover glass may be provided further closer to the image pickup device 1 than the near-infrared cut filter 100.

Hereinafter, the near-infrared cut filter 100 of the present embodiment will be further described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Example 1)
[1. Selection of glass substrate 101]
As the glass substrate 101 of Example 1, phthalate-based glass (CXD700, thickness 0.21 mm) manufactured by HOYA Corporation was selected. FIG. 3 is a diagram showing a spectral transmittance curve of the glass substrate 101 of Example 1, in which the vertical axis represents the transmittance (%) and the horizontal axis represents the wavelength (nm).
As shown in FIG. 3, the glass substrate 101 of this embodiment has an average transmittance of 1.4% (that is, 3% or less) in the wavelength range of 800 to 950 nm.
Further, the glass substrate 101 of this embodiment has an average transmittance of 4.5% (that is, 10% or less) in the wavelength range of 720 to 750 nm.
Further, in the glass substrate 101 of this embodiment, the half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve is about 343 nm (that is, within the range of 335 to 400 nm), and the half-value wavelength (NIR_λ50) on the long wavelength side. Is about 619 nm (that is, in the range of 590 to 630 nm).
Further, the glass substrate 101 of this embodiment has an average transmittance of 15.5% (that is, 18% or less) in the wavelength range of 650 to 720 nm.

[2. Formation of resin layer 102]
Acrylic resin (transparent resin), benzotriazole compound and triazine compound (ultraviolet absorption dye), and squarylium compound and cyanine compound (first near-infrared absorption dye) are mixed in a container at a predetermined mixing ratio to form a resin. The film-forming solution was adjusted, and the obtained resin film-forming solution was applied onto the glass substrate 101 using a spin coater. Then, the glass substrate 101 coated with the resin film forming liquid was placed on a hot plate heated to 160 ° C. and heated for 20 minutes to be cured, thereby producing the near-infrared cut filter 100 of the present embodiment.

FIG. 4 is a diagram showing a spectral transmittance curve of the near-infrared cut filter 100 of Example 1, a spectral transmittance curve (solid line) when the incident angle is 0 °, and a spectral transmittance when the incident angle is 30 °. A curve (broken line) is shown. As shown in FIG. 4, the spectral transmittance curve of the near-infrared cut filter 100 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 410 nm and a half-value wavelength (NIR_λ50) on the long wavelength side. The average transmittance in the wavelength range of about 610 nm and 800 to 950 nm was 1.3%, and a characteristic close to human visual sensitivity was obtained.
Further, since the near-infrared cut filter 100 of this embodiment does not have a reflective film like the conventional near-infrared cut filter, the performance as a cut filter is remarkably improved even when light having an incident angle of 30 ° is incident. The generation of impaired phase shift, wavelength shift and ripple is suppressed.

(Example 2)
In the near-infrared cut filter 100 of Example 2, a fluorophosphate-based glass (CXD700) manufactured by HOYA Co., Ltd. having a thickness of 0.8 mm was selected as the glass base material 101, and the resin layer 102 was formed of an acrylic resin (Acrylic resin). It is different from Example 1 in that it is formed of a transparent resin), a benzotriazole compound and a triazine compound (ultraviolet absorbing dye) (that is, it does not contain a near infrared absorbing dye).

FIG. 5 is a diagram showing a spectral transmittance curve (dotted line) of the glass substrate 101 of Example 2 and a spectral transmittance curve (solid line, broken line) of the near-infrared cut filter 100 of Example 2. As for the spectral transmittance curve of the near-infrared cut filter 100, a spectral transmittance curve (solid line) when the incident angle is 0 ° and a spectral transmittance curve (broken line) when the incident angle is 30 ° are shown.

As shown in FIG. 5, the glass substrate 101 of this embodiment has an average transmittance of 0.1% or less (that is, 3% or less) in the wavelength range of 800 to 950 nm.
Further, the glass substrate 101 of this example has an average transmittance of 0.2% (that is, 10% or less) in the wavelength range of 720 to 750 nm.
Further, in the glass substrate 101 of this embodiment, the half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve is about 353 nm (that is, within the range of 335 to 400 nm), and the half-value wavelength (NIR_λ50) on the long wavelength side. Is about 591 nm (that is, within the range of 590 to 630 nm).
Further, the glass substrate 101 of this embodiment has an average transmittance of 3.1% (that is, 18% or less) in the wavelength range of 650 to 720 nm.

The near-infrared cut filter 100 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 405 nm and a half-value wavelength (NIR_λ50) on the long wavelength side of about 591 nm in the wavelength range of 800 to 950 nm. The average transmittance was 0.1% or less, and a characteristic close to human visual sensitivity was obtained.
Since the near-infrared cut filter 100 of this embodiment does not have a reflective film like the conventional near-infrared cut filter, the performance as a cut filter is remarkably improved even when light having an incident angle of 30 ° is incident. The generation of impaired phase shift, wavelength shift and ripple is suppressed.

(Example 3)
The near-infrared cut filter 100 of Example 3 is different from Example 1 in that a futurate-based glass (CXD700) manufactured by HOYA Corporation having a thickness of 1.0 mm is selected as the glass base material 101.

FIG. 6 is a diagram showing a spectral transmittance curve (dotted line) of the glass substrate 101 of Example 3 and a spectral transmittance curve (solid line, broken line) of the near-infrared cut filter 100 of Example 3. As for the spectral transmittance curve of the near-infrared cut filter 100, a spectral transmittance curve (solid line) when the incident angle is 0 ° and a spectral transmittance curve (broken line) when the incident angle is 30 ° are shown.

As shown in FIG. 6, the glass substrate 101 of this embodiment has an average transmittance of 0.2% (that is, 3% or less) in the wavelength range of 800 to 950 nm.
Further, the glass substrate 101 of this embodiment has an average transmittance of 1.0% (that is, 10% or less) in the wavelength range of 720 to 750 nm.
Further, in the glass substrate 101 of the present embodiment, the half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve is about 347 nm (that is, within the range of 335 to 400 nm), and the half-value wavelength (NIR_λ50) on the long wavelength side. Is about 602 nm (that is, in the range of 590 to 630 nm).
Further, the glass substrate 101 of this embodiment has an average transmittance of 6.8% (that is, 18% or less) in the wavelength range of 650 to 720 nm.

The near-infrared cut filter 100 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 404 nm and a half-value wavelength (NIR_λ50) on the long wavelength side of about 596 nm, in the wavelength range of 800 to 950 nm. The average transmittance was 0.2%, and a characteristic close to human visual sensitivity was obtained.
Since the near-infrared cut filter 100 of this embodiment does not have a reflective film like the conventional near-infrared cut filter, the performance as a cut filter is remarkably improved even when light having an incident angle of 30 ° is incident. The generation of impaired phase shift, wavelength shift and ripple is suppressed.

(Example 4)
For the near-infrared cut filter 100 of Example 4, a cyanine compound (near) of the resin layer 102 was selected from HOYA Corporation's fluoride-based glass (CXD700) having a thickness of 0.23 mm as the glass base material 101. It differs from Example 1 in that the content of the infrared absorbing dye) is changed.

FIG. 7 is a diagram showing a spectral transmittance curve (dotted line) of the glass substrate 101 of Example 4 and a spectral transmittance curve (solid line, broken line) of the near-infrared cut filter 100 of Example 4. As for the spectral transmittance curve of the near-infrared cut filter 100, a spectral transmittance curve (solid line) when the incident angle is 0 ° and a spectral transmittance curve (broken line) when the incident angle is 30 ° are shown.

As shown in FIG. 7, the glass substrate 101 of this embodiment has an average transmittance of 1.0% (that is, 3% or less) in the wavelength range of 800 to 950 nm.
Further, the glass substrate 101 of this embodiment has an average transmittance of 3.4% (that is, 10% or less) in the wavelength range of 720 to 750 nm.
Further, in the glass substrate 101 of this embodiment, the half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve is about 344 nm (that is, within the range of 335 to 400 nm), and the half-value wavelength (NIR_λ50) on the long wavelength side. Is about 615 nm (that is, in the range of 590 to 630 nm).
Further, the glass substrate 101 of this embodiment has an average transmittance of 13.2% (that is, 18% or less) in the wavelength range of 650 to 720 nm.

The near-infrared cut filter 100 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 404 nm and a half-value wavelength (NIR_λ50) on the long wavelength side of about 603 nm in the wavelength range of 800 to 950 nm. The average transmittance was 0.9%, and the characteristics close to those of human visual sensitivity were obtained.
Since the near-infrared cut filter 100 of this embodiment does not have a reflective film like the conventional near-infrared cut filter, the performance as a cut filter is remarkably improved even when light having an incident angle of 30 ° is incident. The generation of impaired phase shift, wavelength shift and ripple is suppressed.

(Example 5)
In the near-infrared cut filter 100 of Example 5, a 0.30 mm-thick HOYA Co., Ltd. fluorinated glass (CXD700) was selected as the glass base material 101, and the resin layer 102 was formed of an acrylic resin (Acrylic resin). A point formed by a transparent resin), a benzotriazole compound and a triazine compound (ultraviolet absorbing dye), a squarylium compound and a cyanine compound (a first near-infrared absorbing dye), and a diionium compound (a second near-infrared absorbing dye) ( That is, the point that the second near-infrared absorbing dye is added) is different from Example 1.

FIG. 8 is a diagram showing a spectral transmittance curve (dotted line) of the glass substrate 101 of Example 5 and a spectral transmittance curve (solid line, broken line) of the near-infrared cut filter 100 of Example 5. As for the spectral transmittance curve of the near-infrared cut filter 100, a spectral transmittance curve (solid line) when the incident angle is 0 ° and a spectral transmittance curve (broken line) when the incident angle is 30 ° are shown.

As shown in FIG. 8, the glass substrate 101 of this embodiment has an average transmittance of 0.2% (that is, 3% or less) in the wavelength range of 800 to 950 nm.
Further, the glass substrate 101 of this embodiment has an average transmittance of 1.3% (that is, 10% or less) in the wavelength range of 720 to 750 nm.
Further, in the glass substrate 101 of this embodiment, the half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve is about 348 nm (that is, within the range of 335 to 400 nm), and the half-value wavelength (NIR_λ50) on the long wavelength side. Is about 604 nm (that is, within the range of 590 to 630 nm).
Further, the glass substrate 101 of this embodiment has an average transmittance of 7.7% (that is, 18% or less) in the wavelength range of 650 to 720 nm.

The near-infrared cut filter 100 of the present embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 406 nm and a half-value wavelength (NIR_λ50) on the long wavelength side of about 604 nm, in a wavelength range of 800 to 950 nm. The average transmittance was 0.1%, and a characteristic close to human visual sensitivity was obtained.
Since the near-infrared cut filter 100 of this embodiment does not have a reflective film like the conventional near-infrared cut filter, the performance as a cut filter is remarkably improved even when light having an incident angle of 30 ° is incident. The generation of impaired phase shift, wavelength shift and ripple is suppressed. (Comparative Example 1)
The near-infrared cut filter of Comparative Example 1 is different from Example 1 in that futurate-based glass (CXA700, thickness 0.21 mm) manufactured by HOYA Corporation is selected as the glass base material, and the resin layer is different from that of Example 1. It is the same as the resin layer 102 of Example 1.

FIG. 9 is a diagram showing a spectral transmittance curve (dotted line) of the glass substrate of Comparative Example 1 and a spectral transmittance curve (solid line, broken line) of the near-infrared cut filter of Comparative Example 1. As for the spectral transmittance curve of the near-infrared cut filter, a spectral transmittance curve (solid line) when the incident angle is 0 ° and a spectral transmittance curve (broken line) when the incident angle is 30 ° are shown.

As shown in FIG. 9, the glass substrate of this modification has an average transmittance of 4.3% (that is, larger than 3%) in the wavelength range of 800 to 950 nm.
Further, the glass substrate of this modification has an average transmittance of 9.7% (that is, 10% or less) in the wavelength range of 720 to 750 nm.
Further, in the glass substrate of this modification, the half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve is about 338 nm (that is, within the range of 335 to 400 nm), and the half-value wavelength (NIR_λ50) on the long wavelength side is. It is about 632 nm (that is, outside the range of 590 to 630 nm).
Further, the glass substrate of this modification has an average transmittance of 23.8% (that is, larger than 18%) in the wavelength range of 650 to 720 nm.

The near-infrared cut filter of this comparative example has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 404 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of about 610 nm, and an average in the wavelength range of 800 to 950 nm. The transmittance was 4.1%. That is, the near-infrared cut filter of this comparative example has a higher average transmittance in the wavelength range of 800 to 950 nm than the near-infrared cut filter 100 of Examples 1 to 5.
The near-infrared cut filter 100 of this modification also does not have a reflective film like the conventional near-infrared cut filter like the near-infrared cut filters 100 of Examples 1 to 5, and therefore has an incident angle of 30 °. Even if light is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance of the cut filter is suppressed.

As described above, the near-infrared cut filter of Comparative Example 1 has a higher average transmittance (that is, larger than 3%) in the wavelength range of 800 to 950 nm as compared with the near-infrared cut filter 100 of Examples 1 to 5. Therefore, the color reproducibility is poor. In order to deal with this problem, it is effective to form a reflective layer as used in the conventional near-infrared cut filter, but if a reflective layer is used, phase shift occurs and wavelength shift or wavelength shift occurs. Problems such as ripples occur.
That is, in the near-infrared cut filter 100 of the present embodiment (Examples 1 to 5), in order to solve such a problem, the glass substrate 101 has a very low average transmittance in the wavelength range of 800 to 950 nm (that is,). (3% or less) is used, and characteristics close to human visual sensitivity are obtained without using a conventional reflective layer.

As described above, since the near-infrared cut filter 100 of the present embodiment does not use the conventional reflective layer, the dependence on the incident angle is extremely small, and the oblique incident characteristics are excellent. Further, in the image pickup apparatus 1 using such a near-infrared cut filter 100, the generation of ghosts is suppressed, so that an image having excellent color reproducibility can be obtained.

The above is the description of the embodiment of the present invention, but the present invention is not limited to the configuration of the above-described embodiment, and various modifications can be made within the scope of the technical idea thereof.

For example, in the present embodiment (Examples 1 to 5), the half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve is close to about 404 to 410 nm, and the half-value wavelength (NIR_λ50) on the long wavelength side is close to about 591 to 610 nm. Although the infrared cut filter 100 has been exemplified, it is not limited to those having such characteristics. By appropriately selecting the ultraviolet absorbing dye, the first near infrared absorbing dye, and the second near infrared absorbing dye of the resin layer 102, and adjusting the mixing ratio of these, the short wavelength side of the transmittance curve can be selected. The half-value wavelength can be adjusted in the range of 385 to 430 nm, and the half-value wavelength on the long wavelength side can be adjusted in the range of 590 to 630 nm.

(Second embodiment)
FIG. 10 is a vertical sectional view illustrating the configuration of the near-infrared cut filter 100A according to the second embodiment of the present invention. As shown in FIG. 10, the near-infrared cut filter 100A of the present embodiment has an antireflection film 103 on the upper surface of the resin layer 102 (the surface opposite to the glass base material 101), and is the other side of the glass base material 101. It differs from the near-infrared cut filter 100 of the first embodiment in that the antireflection film 104 is provided on the main surface (lower surface in FIG. 10).
By forming the

antireflection films

103 and 104 in this way, it is possible to suppress reflection at the interface (that is, the entrance surface and the emission surface) of the near-infrared cut filter 100A, so that the transmittance can be increased (improved). ..

The

antireflection films

103 and 104 of the present embodiment are layers for preventing reflection at the interface between the entrance surface and the emission surface of the near infrared cut filter 100A, specifically, a dielectric film having a low refractive index and a high refractive index. It is composed of a dielectric multilayer film in which dielectric films are alternately laminated.

The material of the dielectric film constituting the dielectric multilayer film can be freely selected according to the desired optical characteristics, but the refractive index of the low refractive index material for forming the low refractive index dielectric layer is , 1.1 to 1.5 is preferable, and as the low refractive index material, for example, SiO ₂ , MgF ₂ , SiO ₂ hollow element, a low refractive index sol gel coat having an aerosol structure, or the like can be applied. Further, the refractive index of the high-refractive index material for forming the high-refractive index dielectric layer is preferably in the range of 2.0 to 2.5, and examples of the high-refractive index material include ZrO ₂ . Ta ₂ O ₅ , TIO ₂ , Nb ₂ O ₅ , and the like can be applied.
Further, a material having a refractive index of 1.4 to 1.6 (for example, SiO ₂ ) can also be used as a high refractive index material, and in this case, a material having a refractive index of 1.1 to 1.3 (for example, aerosol coat) can be used. ) Can be applied as a low refractive index material.

As described above, by using the dielectric multilayer film for the

antireflection films

103 and 104, the antireflection function can be easily imparted by utilizing the interference of light generated by each dielectric film. However, when the number of film layers is large, the optical path length becomes long when the light is obliquely incident, and the interference conditions of the reflected light in each layer are disrupted, which causes problems such as wavelength shift and ripple. Further, such a wavelength shift or ripple causes an increase in reflected light, and is observed as a kind of ghost on the solid-state image sensor 200, which causes a problem that accurate color reproducibility cannot be obtained. Therefore, in the present embodiment, in order to avoid such a problem, the number of film layers of the dielectric multilayer film is set to 10 or less. The number of film layers is particularly preferably 5 or less, more preferably 3 or less.
The thickness of the dielectric film constituting the dielectric multilayer film can be freely selected according to the desired optical characteristics, but is preferably 50 nm to 1 μm, and more preferably 50 nm to 500 nm.
Further, the thickness of the entire dielectric multilayer film (that is, the antireflection films 103 and 104) is set to 500 nm or less.

Although the resin layer 102 of the present embodiment is formed on one main surface (upper surface in FIG. 10) of the glass base material 101, the resin layer 102 is similar to the first embodiment. It may be formed on the other main surface of the glass base material 101 (lower surface in FIG. 10), or may be formed on both sides of the glass base material 101. Further, the resin layer 102 does not necessarily have to be one layer, and may be composed of a plurality of layers.

Hereinafter, the near-infrared cut filter 100A of the present embodiment will be further described with reference to examples, but the present invention is not limited to the following examples.

(Example 6)

Antireflection films

103 and 104 were further formed on the near-infrared cut filter 100 of Example 1 by the following procedure (3. Formation of antireflection films 103 and 104) to prepare the near-infrared cut filter 100A of Example 6. ..
[3. Formation of antireflection films 103 and 104]
On the upper surface of the resin layer 102 of the near-infrared cut filter 100 of Example 1 (the surface opposite to the glass substrate 101) and on the other main surface of the glass substrate 101 (the lower surface in FIG. 10), so-called. Using the sol-gel method, the dielectric thin films (dielectric layers 1 to 5) in Table 1 are sequentially formed (that is, the

antireflection films

103 and 104 are formed), and the near-infrared cut filter 100A of Example 6 is formed. Got

FIG. 11 is a diagram showing a spectral transmittance curve of the near-infrared cut filter 100A of Example 6, a spectral transmittance curve (solid line) when the incident angle is 0 °, and a spectral transmittance when the incident angle is 30 °. A curve (broken line) is shown. As shown in FIG. 11, in the near-infrared cut filter 100A of this embodiment, the half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve is about 390 nm, and the half-value wavelength (NIR_λ50) on the long wavelength side is about 610 nm, 800 to 800. The average transmittance in the wavelength range of 950 nm was 1.2%, and a characteristic close to human visual sensitivity was obtained.
Further, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the

antireflection films

103 and 104, the thickness thereof is sufficiently thin (because it is 500 nm or less), so that the incident angle is 30 °. Even if the light is incident on the surface, the occurrence of phase shift, wavelength shift and ripple, which significantly impairs the performance as a cut filter, is suppressed.
Further, since the near-infrared cut filter 100A of the present embodiment includes the

antireflection films

103 and 104, the transmittance is higher than that of the near-infrared cut filter 100 of the first embodiment (that is, as compared with FIG. 4). , The peak transmittance is about 95%.

(Example 7)

Antireflection films

103 and 104 were formed on the near-infrared cut filter 100 of Example 2 in the same procedure as in Example 6, and the near-infrared cut filter 100A of Example 7 was prepared.

FIG. 12 is a diagram showing a spectral transmittance curve of the near-infrared cut filter 100A of Example 7, a spectral transmittance curve (solid line) when the incident angle is 0 °, and a spectral transmittance when the incident angle is 30 °. A curve (broken line) is shown. As shown in FIG. 12, in the near-infrared cut filter 100A of this embodiment, the half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve is about 403 nm, and the half-value wavelength (NIR_λ50) on the long wavelength side is about 596 nm, 800 to 800. The average transmittance in the wavelength range of 950 nm was 0.1% or less, and a characteristic close to human visual sensitivity was obtained.
Further, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the

antireflection films

103 and 104, the transmittance is higher than that of the near-infrared cut filter 100 of the second embodiment (that is, compared with FIG. 5). , The peak transmittance is about 95%.

(Example 8)

Antireflection films

103 and 104 were formed on the near-infrared cut filter 100 of Example 3 in the same procedure as in Example 6, and the near-infrared cut filter 100A of Example 8 was prepared.

FIG. 13 is a diagram showing a spectral transmittance curve of the near-infrared cut filter 100A of Example 8, a spectral transmittance curve (solid line) when the incident angle is 0 °, and a spectral transmittance when the incident angle is 30 °. A curve (broken line) is shown. As shown in FIG. 13, in the near-infrared cut filter 100A of this embodiment, the half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve is about 402 nm, and the half-value wavelength (NIR_λ50) on the long wavelength side is about 601 nm, 800 to 800. The average transmittance in the wavelength range of 950 nm was 0.2%, and a characteristic close to human visual sensitivity was obtained.
Further, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the

antireflection films

103 and 104, the thickness thereof is sufficiently thin (because it is 500 nm or less), so that the incident angle is 30 °. Even if the light is incident on the surface, the occurrence of phase shift, wavelength shift and ripple, which significantly impairs the performance as a cut filter, is suppressed.
Further, since the near-infrared cut filter 100A of this embodiment includes the

antireflection films

103 and 104, the transmittance is higher than that of the near-infrared cut filter 100 of Example 3 (that is, compared with FIG. 6). , The peak transmittance is about 97%.

(Example 9)

Antireflection films

103 and 104 were formed on the near-infrared cut filter 100 of Example 4 in the same procedure as in Example 6, and the near-infrared cut filter 100A of Example 9 was prepared.

FIG. 14 is a diagram showing a spectral transmittance curve of the near-infrared cut filter 100A of Example 9, a spectral transmittance curve (solid line) when the incident angle is 0 °, and a spectral transmittance when the incident angle is 30 °. A curve (broken line) is shown. As shown in FIG. 14, the near-infrared cut filter 100A of the present embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 402 nm and a half-value wavelength (NIR_λ50) on the long wavelength side of about 608 nm, 800 to 800. The average transmittance in the wavelength range of 950 nm was 0.9%, and a characteristic close to human visual sensitivity was obtained.
Further, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the

antireflection films

103 and 104, the transmittance is higher than that of the near-infrared cut filter 100 of Example 4 (that is, compared with FIG. 7). , The peak transmittance is about 98%.

(Example 10)

Antireflection films

103 and 104 were formed on the near-infrared cut filter 100 of Example 5 in the same procedure as in Example 6, and the near-infrared cut filter 100A of Example 10 was prepared.

FIG. 15 is a diagram showing a spectral transmittance curve of the near-infrared cut filter 100A of Example 10, a spectral transmittance curve (solid line) when the incident angle is 0 °, and a spectral transmittance when the incident angle is 30 °. A curve (broken line) is shown. As shown in FIG. 15, in the near-infrared cut filter 100A of this embodiment, the half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve is about 404 nm, and the half-value wavelength (NIR_λ50) on the long wavelength side is about 604 nm, 800 to 800. The average transmittance in the wavelength range of 950 nm was 0.1%, and a characteristic close to human visual sensitivity was obtained.
Further, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the

antireflection films

103 and 104, the transmittance is higher than that of the near-infrared cut filter 100 of Example 5 (that is, compared with FIG. 8). The peak transmittance is about 93%.

As described above, the near-infrared cut filters 100A of Examples 6 to 10 have excellent oblique incident characteristics and high transmittance. Further, the image pickup apparatus 1 using such a near-infrared cut filter 100 can obtain an image that is bright and has excellent color reproducibility.

(Third embodiment)
FIG. 16 is a vertical sectional view illustrating the configuration of the near-infrared cut filter 100B according to the third embodiment of the present invention. As shown in FIG. 16, the near-infrared cut filter 100B of the present embodiment is close to the first embodiment in that the near-infrared cut filter 100B includes a bonding layer 105 for bonding the glass base material 101 and the resin layer 102. It is different from the infrared cut filter 100.
When the bonding layer 105 is formed in this way, the adhesion between the glass base material 101 and the resin layer 102 can be enhanced, so that the reliability can be improved.

As a result of diligent studies by the present inventor, when a bonding component containing a Si atom and one or more selected from Ti atom, Zr atom and Al atom is used, the adhesion between the glass substrate 101 and the resin layer 102 is enhanced. I found that I could do it. The bonding layer 105 of the present embodiment is based on such findings, and has a single-layer structure containing one or more selected from Ti atoms, Zr atoms, and Al atoms together with Si atoms.
In the present specification, the single-layer structure is a measurement image (image contrast) obtained when measured by a scanning transmission electron microscope-energy dispersive X-ray spectrophotometer (STEM-EDX) under the following measurement conditions. ) Or the layer structure specified from the elemental analysis results to be made of a forming material having the same composition.
<Measurement conditions>
Scanning transmission electron microscope: ARM200F manufactured by JEOL Ltd.
Energy Dispersive X-ray Spectroscopy Analyzer: JED-2300T manufactured by JEOL Ltd.
Sample preparation: Focused ion beam processing (FIB)
Acceleration voltage: 200kV
Elemental analysis: EDX mapping (resolution: 256 x 256)

The thickness of the bonding layer 105 is preferably 1000 nm or less, more preferably 10 to 500 nm, and even more preferably 30 to 300 nm.
When the thickness of the bonding layer 105 is 1000 nm or less, it becomes easy to suppress the occurrence of unevenness during the formation (firing) of the bonding layer 105, and the film surface of the bonding layer 105 can be easily made uniform.
Further, when the thickness of the bonding layer 105 is 10 nm or more, the bonding layer 105 tends to exhibit sufficient bonding strength, and the mechanical strength of the near-infrared cut filter 100B can be easily improved.
In the present specification, the thickness of the bonding layer 105 is the thickness of the bonding layer 105 in the measured image (image contrast) of the cross section of the near-infrared cut filter 100B obtained when measured using the STEM-EDX. It means the arithmetic mean value when the point is measured.

The bonding layer 105 of the present embodiment contains one or more selected from Ti atom, Zr atom and Al atom together with Si atom, but is contained in the bonding layer 105 together with Si atom, Ti atom, Zr atom and Al. The Ti atom is preferable as one or more selected from the atoms.

In the bonding layer 105 of the present embodiment, the ratio α (atomic%) of the total number of Ti atoms, Zr atoms and Al atoms to the total number of Si atoms, Ti atoms, Zr atoms and Al atoms (total number of atoms) is , 0 atomic% and preferably 33.3 atomic% or less, more preferably 9 to 33.3 atomic%, still more preferably 12 to 33.3 atomic%. In the present specification, the ratio α of the total number of Ti atoms, Zr atoms and Al atoms to the total number of Si atoms, Ti atoms, Zr atoms and Al atoms constituting the bonding layer 105 (total number of atoms) α ( Atomic%) means a value calculated by the following method.
(1) The STEM-EDX measurement of the optical filter is performed under the above-mentioned measurement conditions to obtain a STEM-EDX line (EDX line (K line) detection intensity line in the depth direction of each element constituting the optical filter).
(2) EDX ray integrated intensity X _Si of Si atom, EDX ray integrated intensity X _Ti of Ti atom, EDX ray integrated intensity X _Zr of Zr atom, and EDX ray integrated intensity X of Al atom in the region constituting the bonding layer 105. _{Find Al} respectively.
(3) A k-factor (correction coefficient that depends on the acceleration voltage and detection efficiency and differs for each atomic number. For convenience, the k-factor of the Si atom is K _Si , Ti) for each EDX-ray integrated intensity obtained in (2). The value obtained by multiplying the k factor of the atom by K _Ti , the k factor of the Zr atom by K _Zr , and the k factor of the Al atom by K _Al ) can be regarded as corresponding to the weight ratio of each constituent element. Therefore, for example, the weight ratio A _Ti (% by weight) of the Ti atoms constituting the bonding layer can be calculated by the following formula.

(4) Further, it can be considered that the value obtained by dividing the value obtained by multiplying the EDX-ray integrated intensity X of each atom by the k factor by each atomic weight M corresponds to the ratio of the number of atoms of each constituent element. Therefore, when the atomic weight of the Si atom is M _Si , the atomic weight of the Ti atom is M _Ti , the atomic weight of the Zr atom is M _Zr , and the atomic weight of the Al atom is M _Al , for example, the number of Ti atoms constituting the bonding layer 105 is the number of atoms. The ratio α _Ti (atomic%) of can be calculated by the following formula.

Further, the ratio α (atomic%) of the total number of atoms of Ti atom, Zr atom and Al atom constituting the bonding layer 105 can be calculated by the following formula.

For example, when the bonding layer 105 contains Si atoms and Ti atoms but does not contain Zr atoms and Al atoms, the ratio α of the total number of Ti atoms, Zr atoms, and Al atoms constituting the bonding layer 105 ( Atomic%) can be calculated by the following formula.

In this embodiment, K _Si = 1.000, K _Ti = 1.033, K _Zr = 5.696, and K _Al = 1.050.

Hereinafter, the near-infrared cut filter 100B of the present embodiment will be further described with reference to examples, but the present invention is not limited to the following examples.

(Example 11)
A bonding layer 105 was formed on the glass substrate 101 of Example 1 by the following procedure (4. Formation of the bonding layer 105). Then, the resin layer 102 was formed on the upper surface of the bonding layer 105 by the same procedure as in Example 1 (2. Formation of the resin layer 102) to prepare a near-infrared cut filter 100B.
[4. Formation of bonding layer 105]
1. 1. Preparation of Coupling Agent-Containing Coating Solution (1) 0.3 mL of 0.5 N (mol / L) HCl aqueous solution and 2.2 mL of 2-methoxyethanol were weighed in a container and mixed in a hermetically sealed manner.
(2) Tetraethyl orthosilicate (Si (OC ₂ H ₅ ) ₄ ) was added to the above container and mixed for 30 minutes under a closed seal to cause a reaction represented by the following reaction formula.
Si (OC ₂ H ₅ ) ₄ + H ₂ O → HO-Si (OC ₂ H ₅ ) ₃ + C ₂ H ₅ OH
Since all the water is consumed and hydroxyl groups are generated by the above reaction, it was expected that the hydroxide would not precipitate even if Ti alkoxide having a high hydrolysis rate was added, and the solution would be homogeneous.
(3) Titanium (IV) n-butoxide (Ti (OC ₄ H ₉ ) ₄ ) is further added to the above container in a predetermined ratio (for example, 3 to 20 mol%), and the mixture is sealed for 30 minutes. By mixing, a coating liquid containing a coupling agent was prepared.
At this time, it is considered that the reaction represented by the following reaction formula occurred in the container.
4OH-Si (OC ₂ H ₅ ) ₃ + Ti (OC ₄ H ₉ ) ₄ → Ti (O-Si (OC ₂ H ₅ ) ₃ ) ₄ + 4C ₄ H ₉ OH

2. 2. Formation of coating film In the container containing the above-mentioned coupling agent-containing coating liquid, 1.2 mL of 0.5 N HCl aqueous solution, 4.7 mL of water and 8.1 mL of 2-methoxyethanol are weighed and sealed. Was mixed for 30 minutes to prepare a coating film-forming solution.
At this time, it is considered that the reaction represented by the following reaction formula occurred in the container.
Ti {(O-Si (OC ₂ H ₅ ) ₃ } ₄ + 12H ₂ O → Ti {(O-Si (OH) ₃ } ₄ + 12C ₂ H ₅ OH
HO-Si (OC ₂ H ₅ ) ₃ + 3H ₂ O → Si (OH) ₄ + 3C ₂ H ₅ OH
The obtained coating film forming liquid was applied onto the glass substrate 101 using a spin coater so as to have a concentration of 0.03 mL / cm2.
The glass substrate 101 coated with the coating film forming liquid was placed on a hot plate heated to 250 ° C. and heated for 30 minutes for dehydration condensation to form a cured film (bonding layer 105) on the surface.

Next, the resin layer 102 was formed on the upper surface of the bonding layer 105 by the same procedure as in Example 1 (2. Formation of the resin layer 102) to prepare a near-infrared cut filter 100B.

By forming the bonding layer 105 between the glass base material 101 and the resin layer 102 in this way, the adhesion between the glass base material 101 and the resin layer 102 can be significantly improved, and the reliability can be dramatically improved. Can be improved.

The bonding layer 105 of the present embodiment contains one or more selected from Ti atom, Zr atom and Al atom together with Si atom, but instead of forming the bonding layer 105, each component of the bonding layer 105 is used. It can also be contained in the resin layer 102. That is, the resin layer 102 can be configured to contain one or more selected from Ti atoms, Zr atoms, and Al atoms together with Si atoms.

Further, the bonding layer 105 of the present embodiment is said to contain one or more selected from Ti atoms, Zr atoms and Al atoms together with Si atoms, but it is intended to improve the adhesion between the glass substrate 101 and the resin layer 102. For example, a transparent vapor deposition type or coating type adhesive can be applied.

Further, the resin layer 102 of the present embodiment is formed on one main surface (upper surface in FIG. 16) of the glass base material 101 via the bonding layer 105, but is similar to the first embodiment. The resin layer 102 may be formed on the other main surface (lower surface in FIG. 16) of the glass base material 101 via the bonding layer 105, or may be formed on both sides of the glass base material 101. good. Further, the resin layer 102 does not necessarily have to be one layer, and may be composed of a plurality of layers.

It should be noted that the embodiment disclosed this time is an example in all respects and should be considered not to be restrictive. The scope of the present invention is shown by the scope of claims, not the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1: Image pickup device 11: Absorption layer 12: Reflective layer 13: Transparent substrate 100: Near infrared cut filter 100A: Near infrared cut filter 100B: Near infrared cut filter 101: Glass substrate 102: Resin layer 103: Antireflection film 104 : Antireflection film 105: Bonding layer 200: Solid image pickup element 300: Package

Claims

A transparent substrate made of fluoride-based glass or phosphate-based glass and having an average transmittance of 3% or less in the wavelength range of 800 to 950 nm.
A resin layer formed on at least one main surface of the transparent substrate and absorbing light having a specific wavelength,
A near-infrared cut filter characterized by being equipped with.
The near-infrared cut filter according to claim 1, wherein the half-value wavelength on the short wavelength side of the transmittance curve of the transparent substrate is 335 to 400 nm, and the half-value wavelength on the long wavelength side is 590 to 630 nm.
The near-infrared cut filter according to claim 1 or 2, wherein the transparent substrate has an average transmittance of 18% or less in the wavelength range of 650 to 720 nm.
The near-infrared cut filter according to any one of claims 1 to 3, wherein the transparent substrate has an average transmittance of 10% or less in a wavelength range of 720 to 750 nm.
The near-infrared cut filter according to any one of claims 1 to 4, wherein the resin layer contains a transparent resin and a dye uniformly dispersed in the transparent resin.
The near-infrared cut filter according to claim 5, wherein the dye contains an ultraviolet absorbing dye having a maximum absorption wavelength of 340 to 400 nm.
The near-infrared cut filter according to claim 5 or 6, wherein the dye contains a first near-infrared absorbing dye having a maximum absorption wavelength of 650 to 760 nm.
The near-infrared cut filter according to claim 7, wherein the dye contains a second near-infrared absorbing dye having a maximum absorption wavelength of 800 to 1200 nm.
The near-infrared cut filter according to any one of claims 1 to 8, wherein the resin layer contains one or more selected from Ti atom, Zr atom and Al atom together with Si atom.
The near infrared ray according to any one of claims 1 to 9, wherein a bonding layer for enhancing the adhesion between the transparent substrate and the resin layer is provided between the transparent substrate and the resin layer. Cut filter.
The near-infrared cut filter according to claim 10, wherein the bonding layer has a single-layer structure containing one or more selected from Ti atom, Zr atom and Al atom together with Si atom.
In the bonding layer, the ratio of the total number of atoms of Ti atom, Zr atom and Al atom to the total number of Si atom, Ti atom, Zr atom and Al atom is more than 0 atomic% and 33.3 atomic% or less. The near-infrared cut filter according to claim 11.
One of claims 1 to 12, wherein a first antireflection film is provided on the resin layer, and a second antireflection film is provided on the other main surface of the transparent substrate. Near infrared cut filter described in.
The near-infrared cut filter according to claim 13, wherein the half-value wavelength on the short wavelength side of the transmittance curve is 385 to 430 nm, and the half-value wavelength on the long wavelength side is 590 to 630 nm.
13. The near-infrared ray according to claim 13, wherein the first antireflection film and the second antireflection film are each composed of a dielectric multilayer film having a thickness of 500 nm or less. Cut filter.
The near-infrared cut filter according to claim 15, wherein the dielectric multilayer film has 10 or less layers.
The dielectric multilayer film includes a low refractive index film made of a material having a refractive index of 1.1 to 1.5 and a high refractive index film made of a material having a refractive index of 2.0 to 2.5. The near-infrared cut filter according to claim 15 or 16, wherein the above are alternately laminated and formed.
The dielectric multilayer film includes a low refractive index film made of a material having a refractive index of 1.1 to 1.3 and a high refractive index film made of a material having a refractive index of 1.4 to 1.6. The near-infrared cut filter according to claim 15 or 16, wherein the above are alternately laminated and formed.
The near-infrared cut filter according to any one of claims 1 to 18, wherein the thickness of the transparent base material is 0.01 to 1.5 mm.
An image pickup apparatus including a solid-state image pickup device and the near-infrared cut filter according to any one of claims 1 to 19.
The image pickup apparatus according to claim 20, wherein the near-infrared cut filter is arranged immediately in front of the solid-state image pickup element and also serves as a cover glass.