Near-infrared cut filter and imaging device having same

Abstract

Provided is a near-infrared cut filter which has extremely small incident angle dependency and excellent oblique incident characteristics.　This near-infrared cut filter comprises: a transparent base material which has a thickness of 0.16-0.26 mm and an average transmittance of 1% or less in the wavelength band of 800-1,000 nm; and a resin layer which is formed on at least one main surface of the transparent base material and absorbs light of a specific wavelength.

Description

[Technical field]

[0001] The present invention relates to a near-infrared cut filter that is disposed in front of a solid-state imaging element and is used for visual sensitivity correction of the solid-state imaging element, and to an imaging device including the near-infrared cut filter. [Background technology]

[0002] In recent years, imaging devices incorporating solid-state imaging elements such as CCD and CMOS have been used in digital cameras, portable information terminal devices, etc. In such imaging devices, since the solid-state imaging element has a spectral sensitivity ranging from the near ultraviolet region to the near infrared region, a near-infrared cut filter is provided to cut the near-infrared portion of the incident light and correct it to be close to the visual sensitivity of humans. Such a near-infrared cut filter is disposed in the optical path to the solid-state imaging element, and in order to reduce the overall size of the imaging device, a near-infrared cut filter configured to also serve as a cover glass for the imaging device is also in practical use (for example, Patent Document 1).

[0003] FIG. 29 shows an example of the configuration of a near-infrared cut filter (conventional example) described in Patent Document 1. As shown in FIG. 29, the near-infrared cut filter described in Patent Document 1 includes a transparent substrate 13, an absorption layer 11 formed on one main surface of the transparent substrate 13 and absorbing light in the near-infrared wavelength region and the ultraviolet wavelength region, and a reflection layer 12 formed on the other main surface of the transparent substrate 13 and controlling the transmission and blocking of light in a specific wavelength region. The reflection layer 12 is composed 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 dielectric film) are alternately laminated, and the reflection layer 12 is configured so that its spectral transmittance satisfies a predetermined requirement, thereby realizing a near-infrared cut filter having spectral characteristics close to the relative luminous efficiency curve, particularly on the long wavelength side, and having little incidence angle dependency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6119920 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the near-infrared cut filter described in Patent Document 1 has a reflective layer 12 made of a relatively thick (2 to 10 μm) dielectric multilayer film, and therefore has a problem in that when light is obliquely incident on the reflective layer 12, the optical path length becomes long, causing a phase shift.

[0006] Fig. 30 is a diagram showing the spectral transmittance curve of the reflective layer 12 of the near-infrared cut filter of Fig. 29, showing the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°. Also, Fig. 31 is a diagram showing the spectral transmittance curve of the near-infrared cut filter of Fig. 29, showing the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°.

[0007] figure 30 As shown in FIG. 3, when light having an incident angle of 30° is incident on the reflective layer 12, there are problems such as the spectral transmittance curve shifting to the short wavelength side (part P1 in FIG. 30) and the occurrence of ripples in the spectral transmittance curve (part P2 in FIG. 30) due to the influence of phase shift. 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 (part P3 in FIG. 31), which may reduce the color reproducibility of the solid-state imaging element. When a ripple occurs in the spectral transmittance curve of the reflective layer 12, a ripple also occurs in the spectral transmittance curve of the near-infrared cut filter (part P4 in FIG. 31), which may cause a kind of ghost to be observed on the solid-state imaging element. For this reason, there has been a demand for a near-infrared cut filter with excellent oblique incidence characteristics that does not cause a wavelength shift or ripples even with obliquely incident light.

[0008] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a near-infrared cut filter that has extremely little incidence angle dependency and excellent oblique incidence characteristics, and an imaging device equipped with such a near-infrared cut filter. [Means for solving the problem]

[0009] In order to achieve the above object, the present inventors have conducted extensive research and found that by focusing on the 800-1100 nm wavelength region in the spectral transmittance curve of a transparent substrate made of glass (e.g., fluorophosphate glass, phosphate glass, etc.), and using a substrate with a small average transmittance in the 800-1100 nm wavelength region, it is possible to manufacture a cut filter that selectively transmits light in the visible light region without using a reflective film that is used in conventional near-infrared cut filters.The present invention was made based on this finding.

[0010] That is, the near-infrared cut filter of the present invention is characterized by comprising a transparent substrate having a thickness of 0.16 to 0.26 mm and an average transmittance of 1% or less in the wavelength range of 800 to 1100 nm, and a resin layer formed on at least one main surface of the transparent substrate and absorbing light of a specific wavelength.

[0011] According to this configuration, since a reflective layer made of a dielectric multilayer film as in the conventional method is not required (i.e., since no reflective layer is provided), even if light is obliquely incident on the near-infrared cut filter, the optical path length is unlikely to change, and the occurrence of phase shift is suppressed. Therefore, there is almost no wavelength shift or ripple in the spectral transmittance curve of the near-infrared cut filter.

[0012] It is also preferable that the half-maximum wavelength on the short wavelength side of the transmittance curve of the transparent substrate is 300 to 400 nm, and the half-maximum wavelength on the long wavelength side is 590 to 670 nm.

[0013] Moreover, the transparent substrate preferably has an average transmittance of 40% or less in the wavelength range of 650 to 720 nm.

[0014] Moreover, the transparent substrate preferably has an average transmittance of 15% or less in the wavelength range of 720 to 750 nm.

[0015] Moreover, the transparent substrate preferably has an average transmittance of 5% or less in the wavelength range of 800 to 1200 nm.

[0016] The resin layer may contain a transparent resin and a dye uniformly dispersed in the transparent resin. In this case, the dye preferably contains an ultraviolet absorbing dye having a maximum absorption wavelength in the range of 340 to 400 nm. The dye preferably contains a near-infrared absorbing dye having a maximum absorption wavelength in the range of 650 to 900 nm.

[0017] The resin layer contains Si atoms as an essential component, and may contain one or more atoms selected from Ti atoms, Zr atoms, and Al atoms as optional components.

[0018] In addition, a bonding layer for enhancing the adhesion between the transparent substrate and the resin layer can be provided between the transparent substrate and the resin layer. In this case, it is preferable to further provide a bonding layer on the other main surface of the transparent substrate. In addition, it is preferable that the bonding layer has a single layer structure containing one or more atoms selected from Ti atoms, Zr atoms, and Al atoms together with Si atoms. In this case, it is preferable that the ratio 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 in the bonding layer is more than 0 atomic % and 50 atomic % or less.

[0019] Also, a first functional film may be provided on the resin layer, and a second functional film may be provided on the other main surface of the transparent substrate. In this case, it is preferable that the first functional film and the second functional film are optical thin films having at least one of the functions of an anti-reflection film, an infrared cut film, and an ultraviolet cut film. In this case, it is preferable that the first functional film and the second functional film are each composed of a dielectric multilayer film having a thickness of 500 nm or less. In this case, it is preferable that the dielectric multilayer film has 10 layers or less.

[0020] Moreover, the dielectric multilayer film is preferably formed by alternately laminating low-refractive index dielectric films made of a material with a refractive index of 1.1 to 1.5 and high-refractive index dielectric films made of a material with a refractive index of 2.0 to 2.5.

[0021] Moreover, the dielectric multilayer film is preferably formed by alternately laminating low-refractive index dielectric films made of a material with a refractive index of 1.1 to 1.3 and high-refractive index dielectric films made of a material with a refractive index of 1.4 to 1.6.

[0022] It is also preferable that the half-maximum wavelength on the short wavelength side of the transmittance curve is 385 to 430 nm, and the half-maximum wavelength on the long wavelength side is 590 to 660 nm.

[0023] In addition, the difference between the half-value wavelength on the long wavelength side of the transmittance curve of the transparent substrate and the half-value wavelength on the long wavelength side of the transmittance curve of the near-infrared cut filter is preferably 20 nm or less.

[0024] The transparent substrate is preferably made of fluorophosphate glass or phosphate glass.

[0025] From another viewpoint, an imaging device of the present invention is characterized by comprising a solid-state imaging element and any one of the near-infrared cut filters described above. In this case, the near-infrared cut filter can be arranged immediately before the solid-state imaging element and configured to also function as a cover glass. Effect of the Invention

[0026] As described above, the present invention provides a near-infrared cut filter that has extremely little incidence angle dependency and is excellent in oblique incidence characteristics, and also provides an imaging device that includes such a near-infrared cut filter and is excellent in color reproducibility. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a diagram illustrating the configuration of a near-infrared cut filter according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a vertical cross-sectional view illustrating the configuration of an imaging device equipped with a near-infrared cut filter according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram showing the near-infrared cut filter according to the first embodiment (Example 1) of the present invention and the spectral transmittance curve of a glass substrate used in the near-infrared cut filter. [Figure 4] FIG. 4 is a diagram showing the near-infrared cut filter according to the first embodiment (Example 2) of the present invention and the spectral transmittance curve of the glass substrate used in the near-infrared cut filter. [Diagram 5] FIG. 5 is a diagram showing the near-infrared cut filter according to the first embodiment (Example 3) of the present invention and the spectral transmittance curve of the glass substrate used in the near-infrared cut filter. [Figure 6] FIG. 6 is a diagram showing the near-infrared cut filter according to the first embodiment (Example 4) of the present invention and the spectral transmittance curve of the glass substrate used in the near-infrared cut filter. [Figure 7] FIG. 7 is a diagram showing the near-infrared cut filter according to the first embodiment (Example 5) of the present invention and the spectral transmittance curve of the glass substrate used in the near-infrared cut filter. [Figure 8] FIG. 8 is a diagram showing the near-infrared cut filter according to the first embodiment (Example 6) of the present invention and the spectral transmittance curve of the glass substrate used in the near-infrared cut filter. [Figure 9] FIG. 9 is a diagram showing the near-infrared cut filter according to the first embodiment (Example 7) of the present invention and the spectral transmittance curve of the glass substrate used in the near-infrared cut filter. [Figure 10] FIG. 10 is a diagram showing the near-infrared cut filter according to the first embodiment (Example 8) of the present invention and the spectral transmittance curve of the glass substrate used in the near-infrared cut filter. [Figure 11] FIG. 11 is a diagram showing the near-infrared cut filter according to the first embodiment (Example 9) of the present invention and the spectral transmittance curve of the glass substrate used in the near-infrared cut filter. [Figure 12] FIG. 12 is a diagram showing the near-infrared cut filter according to the first embodiment (Example 10) of the present invention and the spectral transmittance curve of the glass substrate used in the near-infrared cut filter. [Figure 13] FIG. 13 is a diagram showing the near-infrared cut filter according to the first embodiment (Example 11) of the present invention and the spectral transmittance curve of the glass substrate used in the near-infrared cut filter. [Figure 14] FIG. 14 is a vertical sectional view illustrating the configuration of a near-infrared cut filter according to a second embodiment of the present invention. [Figure 15] FIG. 15 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 12) of the present invention. [Figure 16] FIG. 16 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 13) of the present invention. [Figure 17] FIG. 17 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 14) of the present invention. [Figure 18] FIG. 18 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 15) of the present invention. [Figure 19] FIG. 19 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 16) of the present invention. [Figure 20] FIG. 20 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 17) of the present invention. [Figure 21] FIG. 21 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 18) of the present invention. [Figure 22] FIG. 22 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 19) of the present invention. [Diagram 23] FIG. 23 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 20) of the present invention. [Figure 24]FIG. 24 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 21) of the present invention. [Diagram 25] FIG. 25 is a diagram showing a spectral transmittance curve of the near-infrared cut filter according to the second embodiment (Example 22) of the present invention. [Figure 26] FIG. 26 is a vertical sectional view illustrating the configuration of a near-infrared cut filter according to a third embodiment (Example 23) of the present invention. [Figure 27] FIG. 27 is a vertical sectional view illustrating the configuration of a near-infrared cut filter according to a third embodiment (Example 24) of the present invention. [Figure 28] FIG. 28 is a vertical sectional view illustrating the configuration of a near-infrared cut filter according to a third embodiment (Example 25) of the present invention. [Figure 29] FIG. 29 is a vertical sectional view showing the configuration of a conventional near-infrared cut filter. [Diagram 30] FIG. 30 is a diagram showing the spectral transmittance curve of a reflective layer used in a conventional near-infrared cut filter. [Diagram 31] FIG. 31 is a diagram showing a spectral transmittance curve of a conventional near-infrared cut filter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0029] (First embodiment) Fig. 1 is a diagram for explaining the configuration of a near-infrared cut filter 100 according to a first embodiment of the present invention, Fig. 1(a) is a plan view, and Fig. 1(b) is a longitudinal sectional view. Fig. 2 is a longitudinal sectional view for explaining the configuration of an imaging device 1 in which an opening of a package 300 of a solid-state imaging element 200 is sealed by the near-infrared cut filter 100 of this embodiment. As shown in Figs. 1 and 2, the near-infrared cut filter 100 of this embodiment is attached to the front of the package 300 that houses the solid-state imaging element 200, and is an optical element that protects the solid-state imaging element 200 and is used for luminosity correction of the solid-state imaging element 200.

[0030] As shown in FIG. 1, the near-infrared cut filter 100 of this embodiment has a rectangular plate-like appearance (e.g., 6 mm (horizontal) × 5 mm (vertical)) and is composed of a glass substrate 101 (transparent substrate) and a resin layer 102 formed on one of the main surfaces of the glass substrate 101 (the upper surface in FIG. 1(b)).

[0031] [Glass substrate] The glass substrate 101 of this embodiment is an absorbing glass substrate made of, for example, phosphate glass or fluorophosphate glass. From the viewpoint of achieving small size and weight reduction, the thickness of the glass substrate 101 of this embodiment is preferably 0.35 mm or less, and more preferably 0.16 to 0.26 mm.

[0032] The phosphate-based glass in this embodiment is a glass containing P and O as essential components and other optional components, and is particularly preferably a glass containing CuO. The phosphate-based glass containing CuO can absorb near-infrared light more effectively. Examples of other optional components of the phosphate-based glass include Ca, Mg, Sr, Ba, Li, Na, K, and Cs.

[0033] Specific examples of phosphate-based glasses include: P 2 O 5 : More than 0% by mass and 80% by mass or less, Al 2 O 3 : 0~40% by mass, BaO: 0~40% by mass, CuO: 0~40% by mass It is preferred that the compound contains

[0034] In addition, the fluorophosphate glass in this embodiment is a glass containing P, O, and F as essential components and other optional components, and is particularly preferably one containing CuO. The fluorophosphate glass contains CuO, so that it can absorb near-infrared light more effectively. Examples of other optional components of the fluorophosphate glass include Ca, Mg, Sr, Ba, Li, Na, K, and Cs.

[0035] In addition, the fluorophosphate glass preferably contains BaO. By containing 0% or more of BaO, the devitrification resistance and melting property of the glass can be improved. If the content is more than 10%, the glass is easily devitrified, so 0 to 10% is preferable. In addition, the content of BaO is more preferably 1 to 10%, and further preferably 1 to 5%.

[0036] In addition, as a fluorophosphate glass, Al 2 O 3 Preferably, those containing Al are used. 2 O 3 By containing 0% or more, the stability and chemical durability of the glass can be improved. If the content is more than 10%, the glass is easily devitrified, so 0 to 10% is preferable. 2 O 3 The content is more preferably 1 to 10%, and further preferably 1 to 5%.

[0037] As for fluorophosphate glass, Y 2 O 3 Preferably, the compound containing Y 2 O 3 By containing 0% or more, it is possible to increase the refractive index while maintaining thermal stability. If it is more than 10%, devitrification is likely to occur, and the glass transition temperature and deformation point temperature increase, so 0 to 10% is preferable. 2 O 3The content is more preferably 1 to 10%, and further preferably 1 to 5%.

[0038] As for fluorophosphate glass, BaCl 2 Preferably, BaCl 2 By introducing an appropriate amount of Cl into the glass, the difference between the crystallization onset temperature (Tx) and the glass transition temperature (Tg) of the glass becomes large, and the stability of the glass against devitrification is improved. If the content is more than 10%, the glass becomes prone to devitrification, so 0 to 10% is preferable. In addition, BaCl 2 The content is more preferably 1 to 10%, and further preferably 1 to 5%.

[0039] Specific examples of fluorophosphate glasses include: 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 and further contains fluoride in an amount of more than 0 mass% and not more than 40 mass%. The one is preferred.

[0040] Also, P 2 O 5 : 20~60% by mass, Al 2 O 3 : 0~10% by mass, BaO: 0~10% by mass, CuO: 0~10% by mass and further contains 1 to 30 mass% of fluoride. Things are more preferable.

[0041] Also, P 2 O 5 : 20~60% by mass, Al 2 O 3 : 1~10% by mass, BaO: 1~10% by mass, CuO: 1~10% by mass and further contains 2 to 30 mass% of fluoride. It is even more preferable.

[0042] The above fluoride is MgF 2 , CaF 2 , SrF 2 One or more selected from the following may be mentioned.

[0043] Specific examples of such fluorophosphate-based glasses include: P 2 O 5 : 40~50% by mass, Al 2 O 3 : 1~10% by mass, BaO: 1~10% by mass, CuO: 1~10% by mass, MgF 2 : 1~10% by mass, CaF 2 : 1~10% by mass, SrF 2 : 1~10% by mass, Y 2 O 3 : 1~10% by mass, BaCl 2 : 0~1% by mass, Particularly preferred are those containing:

[0044] Although details will be described later, the glass substrate 101 of this embodiment is preferably configured so that the average transmittance in the wavelength range of 800 to 1100 nm is 3% or less, and more preferably 1% or less. In this way, by using a glass substrate 101 having a small average transmittance in the wavelength range of 800 to 1100 nm, a cut filter that selectively transmits light in the visible light range can be manufactured without using a reflective film (dielectric multilayer film) that has been used in conventional near-infrared cut filters.

[0045] Moreover, the glass substrate 101 preferably has an average transmittance in the wavelength range of 720 to 750 nm of 15% or less, more preferably 10% or less, and even more preferably 8% or less. Moreover, the glass substrate 101 preferably has an average transmittance of 40% or less in the wavelength range of 650 to 720 nm, more preferably 10% or less, and even more preferably 8% or less. Furthermore, the glass substrate 101 preferably has an average transmittance of 5% or less in the wavelength range of 800 to 1200 nm, more preferably 3% or less, and even more preferably 2% or less.

[0046] In addition, the glass substrate 101 has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve in the range of preferably 300 to 400 nm, more preferably 305 to 350 nm, and even more preferably 310 to 340 nm. In addition, the glass substrate 101 has a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve in the range of preferably 590 to 670 nm, and more preferably 610 to 650 nm. In this specification, the half-value wavelength refers to the wavelength at which the transmittance is 50%, the half-value wavelength (UV_λ50) on the short wavelength side refers to the wavelength at which the transmittance is 50% at the rising edge of the transmittance curve, and the half-value wavelength (NIR_λ50) on the long wavelength side refers to the wavelength at which the transmittance is 50% at the falling edge of the transmittance curve.

[0047] [Resin layer] The resin layer 102 of the present embodiment is a layer composed of a dye that absorbs light of a specific wavelength and a resin. 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 preferably contains the dye uniformly dissolved or dispersed in the transparent resin. Moreover, the resin layer 102 of this embodiment preferably contains Si atoms as an essential component, and one or more atoms selected from Ti atoms, Zr atoms, and Al atoms as optional components.

[0048] As the near-infrared absorbing dye constituting the resin layer 102, any conventionally known dye can be used, for example, one or more selected from cyanine-based dyes, polymethine-based dyes, squarylium-based dyes, porphyrin-based dyes, metal dithiol complex-based dyes, phthalocyanine-based dyes, diimonium-based dyes, and inorganic oxide particles can be used, and one or more selected from squarylium-based dyes, cyanine-based dyes, and phthalocyanine-based dyes are more preferable.

[0049] The ultraviolet absorbing dye constituting the resin layer 102 may be any conventionally known dye, such as one or more selected from benzotriazole-based compounds, benzophenone-based compounds, triazine-based compounds, styryl-based compounds, benzoxazinone-based compounds, cyanoacrylates, oxanilide-based compounds, salicylate-based compounds, formamidine-based compounds, indole-based compounds, and azomethine-based compounds. More preferably, one or more selected from benzotriazole-based compounds, benzophenone-based compounds, triazine-based compounds, and styryl-based compounds.

[0050] The resin constituting the resin layer 102 may be a conventionally known transparent resin, and may be one or more selected from acrylic resin, epoxy resin, enethiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, polyparaphenylene resin, polyarylene ether phosphine oxide resin, polyimide resin, polyamideimide resin, polyolefin resin, cyclic olefin resin, and polyester resin. As the transparent resin, from the viewpoint of transparency, solubility of the near infrared absorbing dye in the transparent resin, and heat resistance, a resin having a high glass transition point (Tg) is preferable, and therefore a thermosetting resin is suitable. Specifically, one or more selected from polyester resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, polyimide resin, and epoxy resin may be used. As the polyester resin, one or more selected from polyethylene terephthalate resin and polyethylene naphthalate resin are preferable. In addition, even if the resin is a thermoplastic resin, it may be suitably used as a transparent resin by increasing heat resistance by adjusting functional groups, etc. For example, acrylic resins, polyamide resins, polyolefin resins, etc., whose heat resistance can be improved by adjusting functional groups, etc., can also be used as the transparent resin.

[0051] In addition to the near-infrared absorbing dye and transparent resin, the resin layer 102 may further contain optional components such as a color correction dye, a leveling agent, an antistatic agent, a heat stabilizer, a light stabilizer, an antioxidant, a dispersant, a flame retardant, a lubricant, and a plasticizer, as long as the effects of the present invention are not impaired.

[0052] The resin layer 102 can be formed, for example, by dissolving or dispersing a dye, a transparent resin, and optional ingredients in a solvent to prepare a resin film-forming liquid, applying the liquid, drying it, and curing it as necessary. The resin film-forming liquid may contain a known surfactant such as a cationic, anionic, or nonionic surfactant.

[0053] The resin film-forming liquid can be applied by one or more coating methods selected from the group consisting of dip coating, cast coating, spray coating, and spin coating.

[0054] In this way, the resin layer 102 is a layer formed on the glass substrate 101 and configured to absorb light of a specific wavelength, and by setting the absorption wavelength in accordance with the spectral transmittance characteristics of the glass substrate 101 (i.e., selecting an optimal dye), light in the desired visible light region can be extracted. Specifically, the resin layer 102 of this embodiment may contain an ultraviolet absorbing dye having a maximum absorption wavelength in the range of 340 to 400 nm and a near infrared absorbing dye having a maximum absorption wavelength in the range of 650 to 900 nm. In this embodiment, the resin layer 102 is formed on one of the main surfaces of the glass substrate 101 (the upper surface in FIG. 1(b)), but is not limited to this configuration. The resin layer 102 may be formed on the other main surface of the glass substrate 101 (the lower surface in FIG. 1(b)), or may be formed on both surfaces of the glass substrate 101. In addition, the resin layer 102 does not necessarily have to be a single layer, and may be configured with multiple layers.

[0055] The spectral transmittance curve of the near-infrared cut filter 100 having such a resin layer 102 formed thereon has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of 385 to 430 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of 590 to 660 nm, and an average transmittance of 3.0% or less in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans (details will be described later). In addition, since the near-infrared cut filter 100 of this embodiment is attached to the front surface of the solid-state imaging element 200, from the viewpoint of the amount of light incident on the solid-state imaging element 200, it is preferable that the difference between the half-value wavelength (UV_λ50) on the short wavelength side and the half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve is large, and in particular, the longer the half-value wavelength (NIR_λ50) on the long wavelength side within the range of human visual sensitivity, the more preferable. Therefore, in this embodiment, the half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of the near-infrared cut filter 100 is set to be close to the half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of the glass substrate 101. More specifically, in this embodiment, the difference between the half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of the glass substrate 101 and the half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of the near-infrared cut filter 100 is configured to be 20 nm or less. The difference between the two is more preferably 15 nm or less, and even more preferably 10 nm or less.

[0056] [Imaging device] Next, an imaging device according to the present invention will be described. As shown in Fig. 2, the imaging device 1 according to the present invention includes a solid-state imaging element 200, a package 300 that houses the solid-state imaging element 200, and a near-infrared cut filter 100 that is attached to the front surface of the package 300.

[0057] The solid-state imaging element 200 may be an image sensor such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

[0058] The solid-state imaging element 200 is disposed in approximately the center of the bottom surface of the square-shaped package 300, and is attached to the opening of the package 300 so that the other main surface side of the near-infrared cut filter 100 (the lower side in FIG. 1(b)) faces the solid-state imaging element 200. Note that in FIG. 2, the resin layer 102 side of the near-infrared cut filter 100 is the incident surface onto which light heading toward the solid-state imaging element 200 is incident, and the other main surface side of the near-infrared cut filter 100 is the exit surface, but this is not necessarily limited to such a configuration, and the near-infrared cut filter 100 may be attached upside down (i.e., so that the resin layer 102 faces the solid-state imaging element 200).

[0059] 2, the near-infrared cut filter 100 is attached to the opening of the package 300 and serves as a so-called cover glass, but the present invention is not necessarily limited to such a configuration. For example, the imaging device 1 may include a lens group (not shown) that guides light to the solid-state imaging element 200. In this case, for example, the near-infrared cut filter 100 may be disposed closer to the imaging device 1 than the lens group, and a cover glass may be provided closer to the imaging device 1 than the near-infrared cut filter 100.

[0060] The near-infrared cut filter 100 of this embodiment will be further described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0061] Example 1 [1. Selection of glass substrate 101] As the glass substrate 101 of Example 1, fluorophosphate glass (CXD700, thickness 0.35 mm) manufactured by HOYA Corporation was selected. FIG. 3 is a diagram showing the spectral transmittance curve (dotted line) of the glass substrate 101 of Example 1 and the spectral transmittance curves (solid line, dashed line) of the near-infrared cut filter 100 of Example 1. Note that the vertical axis of FIG. 3 is transmittance (%), and the horizontal axis is wavelength (nm). In addition, the spectral transmittance curve of the near-infrared cut filter 100 shows the spectral transmittance curve (solid line) at an incident angle of 0° and the spectral transmittance curve (dashed line) at an incident angle of 30°. As shown in FIG. 3, the glass substrate 101 of this example has an average transmittance of 0.34% (that is, 1% or less) in the wavelength range of 800 to 1100 nm. Moreover, the glass substrate 101 of this embodiment has an average transmittance of 0.62% (that is, 15% or less) in the wavelength range of 720 to 750 nm. Moreover, the glass substrate 101 has an average transmittance of 5.3% (that is, 40% or less) in the wavelength range of 650 to 720 nm. Moreover, the glass substrate 101 has an average transmittance of 0.93% (that is, 5% or less) in the wavelength range of 800 to 1200 nm. In addition, the glass substrate 101 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of approximately 350 nm (i.e., within the range of 300 to 400 nm) and a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 599 nm (i.e., within the range of 590 to 670 nm).

[0062] [2. Formation of resin layer 102] In a container, an acrylic resin (transparent resin), a styryl compound, a triazine compound (ultraviolet absorbing dye), and a squarylium compound (near infrared absorbing dye) were mixed at a predetermined mixing ratio to prepare a resin film forming liquid, and the obtained resin film forming liquid was applied onto a glass substrate 101 using a spin coater. Then, the glass substrate 101 to which the resin film forming liquid was applied was placed on a hot plate heated to 160° C. and heated for 20 minutes to harden, thereby producing a near infrared cut filter 100 of this embodiment.

[0063] As shown in FIG. 3, the spectral transmittance curve (solid line, dashed line) 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 approximately 413 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 591 nm, and an average transmittance of 0.34% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of the human eye. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100 was 8 nm. Furthermore, since the near-infrared cut filter 100 of this embodiment does not have a reflective film like conventional near-infrared cut filters, even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance as a cut filter is suppressed.

[0064] Example 2 The near-infrared cut filter 100 of Example 2 differs from Example 1 in that a fluorophosphate glass (CXD700) having a thickness of 0.3 mm manufactured by HOYA Corporation is selected as the glass substrate 101, and the content of the squarylium compound (near-infrared absorbing pigment) in the resin layer 102 is changed.

[0065] 4 is a diagram showing the spectral transmittance curve (dotted line) of the glass substrate 101 of Example 2 and the spectral transmittance curves (solid line, dashed line) of the near-infrared cut filter 100 of Example 2. Note that the spectral transmittance curve of the near-infrared cut filter 100 shows the spectral transmittance curve (solid line) at an incident angle of 0° and the spectral transmittance curve (dashed line) at an incident angle of 30°.

[0066] As shown in FIG. 4, the glass substrate 101 of this example has an average transmittance of 0.71% or less (that is, 1% or less) in the wavelength range of 800 to 1100 nm. Moreover, the glass substrate 101 of this embodiment has an average transmittance of 1.26% (that is, 15% or less) in the wavelength range of 720 to 750 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 7.7% (that is, 40% or less) in the wavelength range of 650 to 720 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 1.65% (that is, 5% or less) in the wavelength range of 800 to 1200 nm. In addition, the glass substrate 101 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of approximately 348 nm (i.e., within the range of 300 to 400 nm) and a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 604 nm (i.e., within the range of 590 to 670 nm).

[0067] 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 approximately 411 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 600 nm, and an average transmittance of 0.71% or less in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of the human eye. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100 was 4 nm. The near-infrared cut filter 100 of this embodiment also does not have a reflective film like conventional near-infrared cut filters, so even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance of the cut filter is suppressed.

[0068] Example 3 The near-infrared cut filter 100 of Example 3 differs from Example 1 in that a phosphate-based glass having a thickness of 0.30 mm newly developed by HOYA Corporation (patent application filed (Patent Application No. 2020-119553 (filing date: July 10, 2020))) is selected as the glass substrate 101, and that the resin layer 102 is formed from an acrylic resin (transparent resin), a styryl-based compound, a triazine-based compound (ultraviolet absorbing pigment), a squarylium-based compound, and a cyanine-based compound (near-infrared absorbing pigment) (i.e., the type of near-infrared absorbing pigment has been changed).

[0069] 5 is a diagram showing the spectral transmittance curve (dotted line) of the glass substrate 101 of Example 3 and the spectral transmittance curves (solid line, dashed line) of the near-infrared cut filter 100 of Example 3. Note that the spectral transmittance curve of the near-infrared cut filter 100 shows the spectral transmittance curve (solid line) at an incident angle of 0° and the spectral transmittance curve (dashed line) at an incident angle of 30°.

[0070] As shown in FIG. 5, the glass substrate 101 of this example has an average transmittance of 0.03% (that is, 1% or less) in the wavelength range of 800 to 1100 nm. Moreover, the glass substrate 101 of this embodiment has an average transmittance of 1.03% (that is, 15% or less) in the wavelength range of 720 to 750 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 11.1% (that is, 40% or less) in the wavelength range of 650 to 720 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 0.11% (that is, 5% or less) in the wavelength range of 800 to 1200 nm. In addition, the glass substrate 101 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of approximately 319 nm (i.e., within the range of 300 to 400 nm) and a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 622 nm (i.e., within the range of 590 to 670 nm).

[0071] 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 approximately 413 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 610 nm, and an average transmittance of 0.03% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of the human eye. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100 was 12 nm. The near-infrared cut filter 100 of this embodiment also does not have a reflective film like conventional near-infrared cut filters, so even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance of the cut filter is suppressed.

[0072] Example 4 The near-infrared cut filter 100 of Example 4 differs from Example 3 in that a glass substrate 101 having a thickness of 0.26 mm is selected, and the type and content of the near-infrared absorbing dye in the resin layer 102 are changed.

[0073] 6 is a diagram showing the spectral transmittance curve (dotted line) of the glass substrate 101 of Example 4 and the spectral transmittance curves (solid line, dashed line) of the near-infrared cut filter 100 of Example 4. Note that the spectral transmittance curve of the near-infrared cut filter 100 shows the spectral transmittance curve (solid line) at an incident angle of 0° and the spectral transmittance curve (dashed line) at an incident angle of 30°.

[0074] As shown in FIG. 6, the glass substrate 101 of this example has an average transmittance of 0.09% (that is, 1% or less) in the wavelength range of 800 to 1100 nm. Moreover, the glass substrate 101 of this embodiment has an average transmittance of 1.85% (that is, 15% or less) in the wavelength range of 720 to 750 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 14.3% (that is, 40% or less) in the wavelength range of 650 to 720 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 0.25% (that is, 5% or less) in the wavelength range of 800 to 1200 nm. In addition, the glass substrate 101 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of approximately 317 nm (i.e., within the range of 300 to 400 nm) and a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 628 nm (i.e., within the range of 590 to 670 nm).

[0075] 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 approximately 411 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 619 nm, and an average transmittance of 0.08% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100 was 9 nm. The near-infrared cut filter 100 of this embodiment also does not have a reflective film like conventional near-infrared cut filters, so even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance of the cut filter is suppressed.

[0076] Example 5 The near-infrared cut filter 100 of Example 5 differs from Example 3 in that a glass substrate 101 having a thickness of 0.25 mm is selected, and the type and content of the near-infrared absorbing dye in the resin layer 102 are changed.

[0077] 7 is a diagram showing the spectral transmittance curve (dotted line) of the glass substrate 101 of Example 5 and the spectral transmittance curves (solid line, dashed line) of the near-infrared cut filter 100 of Example 5. Note that the spectral transmittance curve of the near-infrared cut filter 100 shows the spectral transmittance curve (solid line) at an incident angle of 0° and the spectral transmittance curve (dashed line) at an incident angle of 30°.

[0078] As shown in FIG. 7, the glass substrate 101 of this example has an average transmittance of 0.11% (that is, 1% or less) in the wavelength range of 800 to 1100 nm. Moreover, the glass substrate 101 of this embodiment has an average transmittance of 2.15% (that is, 15% or less) in the wavelength range of 720 to 750 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 15.3% (that is, 40% or less) in the wavelength range of 650 to 720 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 0.31% (that is, 5% or less) in the wavelength range of 800 to 1200 nm. In addition, the glass substrate 101 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of approximately 316 nm (i.e., within the range of 300 to 400 nm) and a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 629 nm (i.e., within the range of 590 to 670 nm).

[0079] 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 approximately 411 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 620 nm, and an average transmittance of 0.31% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of the human eye. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100 was 9 nm. The near-infrared cut filter 100 of this embodiment also does not have a reflective film like conventional near-infrared cut filters, so even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance of the cut filter is suppressed.

[0080] Example 6 The near-infrared cut filter 100 of Example 6 differs from Example 3 in that a glass substrate 101 having a thickness of 0.227 mm is selected, and the type and content of the near-infrared absorbing dye in the resin layer 102 are changed.

[0081] 8 is a diagram showing the spectral transmittance curve (dotted line) of the glass substrate 101 of Example 6 and the spectral transmittance curves (solid line, dashed line) of the near-infrared cut filter 100 of Example 6. Note that the spectral transmittance curve of the near-infrared cut filter 100 shows the spectral transmittance curve (solid line) at an incident angle of 0° and the spectral transmittance curve (dashed line) at an incident angle of 30°.

[0082] As shown in FIG. 8, the glass substrate 101 of this example has an average transmittance of 0.20% (that is, 1% or less) in the wavelength range of 800 to 1100 nm. Moreover, the glass substrate 101 of this embodiment has an average transmittance of 3.02% (that is, 15% or less) in the wavelength range of 720 to 750 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 17.7% (that is, 40% or less) in the wavelength range of 650 to 720 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 0.49% (that is, 5% or less) in the wavelength range of 800 to 1200 nm. In addition, the glass substrate 101 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of approximately 315 nm (i.e., within the range of 300 to 400 nm) and a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 633 nm (i.e., within the range of 590 to 670 nm).

[0083] 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 approximately 411 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 625 nm, and an average transmittance of 0.20% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100 was 8 nm. The near-infrared cut filter 100 of this embodiment also does not have a reflective film like conventional near-infrared cut filters, so even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance of the cut filter is suppressed.

[0084] Example 7 The near-infrared cut filter 100 of Example 7 differs from Example 3 in that a glass substrate 101 having a thickness of 0.210 mm is selected, and the type of near-infrared absorbing dye in the resin layer 102 is only a squarylium-based compound.

[0085] 9 is a diagram showing the spectral transmittance curve (dotted line) of the glass substrate 101 of Example 7 and the spectral transmittance curves (solid line, dashed line) of the near-infrared cut filter 100 of Example 7. Note that the spectral transmittance curve of the near-infrared cut filter 100 shows the spectral transmittance curve (solid line) at an incident angle of 0° and the spectral transmittance curve (dashed line) at an incident angle of 30°.

[0086] As shown in FIG. 9, the glass substrate 101 of this example has an average transmittance of 0.31% (that is, 1% or less) in the wavelength range of 800 to 1100 nm. Moreover, the glass substrate 101 of this embodiment has an average transmittance of 3.88% (that is, 15% or less) in the wavelength range of 720 to 750 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 19.9% ​​(that is, 40% or less) in the wavelength range of 650 to 720 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 0.70% (that is, 5% or less) in the wavelength range of 800 to 1200 nm. In addition, the glass substrate 101 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of approximately 314 nm (i.e., within the range of 300 to 400 nm) and a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 636 nm (i.e., within the range of 590 to 670 nm).

[0087] 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 approximately 418 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 625 nm, and an average transmittance of 0.27% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of the human eye. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100 was 11 nm. The near-infrared cut filter 100 of this embodiment also does not have a reflective film like conventional near-infrared cut filters, so even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance of the cut filter is suppressed.

[0088] Example 8 The near-infrared cut filter 100 of Example 8 is different from Example 7 in that the content of the near-infrared absorbing dye in the resin layer 102 is changed.

[0089] 10 is a diagram showing the spectral transmittance curve (dotted line) of the glass substrate 101 of Example 8 and the spectral transmittance curves (solid line, dashed line) of the near-infrared cut filter 100 of Example 8. Note that the spectral transmittance curve of the near-infrared cut filter 100 shows the spectral transmittance curve (solid line) at an incident angle of 0° and the spectral transmittance curve (dashed line) at an incident angle of 30°.

[0090] As shown in FIG. 10, 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 approximately 412 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 630 nm, and an average transmittance of 0.29% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100 was 6 nm. The near-infrared cut filter 100 of this embodiment also does not have a reflective film like conventional near-infrared cut filters, so even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance of the cut filter is suppressed.

[0091] Example 9 The near-infrared cut filter 100 of Example 9 differs from Example 8 in that a glass substrate 101 having a thickness of 0.165 mm is selected, and the type and content of the near-infrared absorbing dye in the resin layer 102 are changed.

[0092] 11 is a diagram showing the spectral transmittance curve (dotted line) of the glass substrate 101 of Example 9 and the spectral transmittance curves (solid line, dashed line) of the near-infrared cut filter 100 of Example 9. Note that the spectral transmittance curve of the near-infrared cut filter 100 shows the spectral transmittance curve (solid line) at an incident angle of 0° and the spectral transmittance curve (dashed line) at an incident angle of 30°.

[0093] As shown in FIG. 11, the glass substrate 101 of this example has an average transmittance of 1.02% (that is, 3% or less) in the wavelength range of 800 to 1100 nm. Moreover, the glass substrate 101 of this embodiment has an average transmittance of 7.58% (that is, 15% or less) in the wavelength range of 720 to 750 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 26.9% (that is, 40% or less) in the wavelength range of 650 to 720 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 1.80% (that is, 5% or less) in the wavelength range of 800 to 1200 nm. In addition, the glass substrate 101 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of approximately 311 nm (i.e., within the range of 300 to 400 nm) and a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 647 nm (i.e., within the range of 590 to 670 nm).

[0094] 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 approximately 410 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 645 nm, and an average transmittance of 0.96% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of the human eye. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100 was 2 nm. The near-infrared cut filter 100 of this embodiment also does not have a reflective film like conventional near-infrared cut filters, so even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance of the cut filter is suppressed.

[0095] Example 10 The near-infrared cut filter 100 of Example 10 differs from Example 9 in that the glass substrate 101 has a thickness of 0.150 mm, and the content of the near-infrared absorbing dye in the resin layer 102 is changed.

[0096] 12 is a diagram showing the spectral transmittance curve (dotted line) of the glass substrate 101 of Example 10 and the spectral transmittance curves (solid line, dashed line) of the near-infrared cut filter 100 of Example 10. Note that the spectral transmittance curve of the near-infrared cut filter 100 shows the spectral transmittance curve (solid line) at an incident angle of 0° and the spectral transmittance curve (dashed line) at an incident angle of 30°.

[0097] As shown in FIG. 12, the glass substrate 101 of this example has an average transmittance of 1.52% (that is, 3% or less) in the wavelength range of 800 to 1100 nm. Moreover, the glass substrate 101 of this embodiment has an average transmittance of 9.48% (that is, 15% or less) in the wavelength range of 720 to 750 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 29.9% (that is, 40% or less) in the wavelength range of 650 to 720 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 2.50% (that is, 5% or less) in the wavelength range of 800 to 1200 nm. In addition, the glass substrate 101 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of approximately 310 nm (i.e., within the range of 300 to 400 nm) and a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 651 nm (i.e., within the range of 590 to 670 nm).

[0098] 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 approximately 410 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 650 nm, and an average transmittance of 1.46% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of the human eye. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100 was 1 nm. The near-infrared cut filter 100 of this embodiment also does not have a reflective film like conventional near-infrared cut filters, so even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance of the cut filter is suppressed.

[0099] Example 11 The near-infrared cut filter 100 of Example 11 differs from Example 3 in that a glass substrate 101 having a thickness of 0.134 mm is selected, and the type of near-infrared absorbing dye in the resin layer 102 is only a cyanine compound.

[0100] 13 is a diagram showing the spectral transmittance curve (dotted line) of the glass substrate 101 of Example 11 and the spectral transmittance curves (solid line, dashed line) of the near-infrared cut filter 100 of Example 11. Note that the spectral transmittance curve of the near-infrared cut filter 100 shows the spectral transmittance curve (solid line) at an incident angle of 0° and the spectral transmittance curve (dashed line) at an incident angle of 30°.

[0101] As shown in FIG. 13, the glass substrate 101 of this example has an average transmittance of 2.33% (that is, 3% or less) in the wavelength range of 800 to 1100 nm. Moreover, the glass substrate 101 of this embodiment has an average transmittance of 12.05% (that is, 15% or less) in the wavelength range of 720 to 750 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 33.5% (that is, 40% or less) in the wavelength range of 650 to 720 nm. Also, In this embodiment The glass substrate 101 has an average transmittance of 3.63% (that is, 5% or less) in the wavelength range of 800 to 1200 nm. In addition, the glass substrate 101 of this embodiment has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of approximately 309 nm (i.e., within the range of 300 to 400 nm) and a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 656 nm (i.e., within the range of 590 to 670 nm).

[0102] 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 approximately 410 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of approximately 651 nm, and an average transmittance of 1.96% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of the human eye. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100 was 5 nm. The near-infrared cut filter 100 of this embodiment also does not have a reflective film like conventional near-infrared cut filters, so even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance of the cut filter is suppressed.

[0103] As described above, in the near-infrared cut filter 100 of the present embodiment (Examples 1 to 11), a glass substrate 101 having a very low average transmittance in the wavelength range of 800 to 1100 nm (i.e., 3% or less or 1% or less) is used, and characteristics close to the human visual sensitivity are obtained without using a conventional reflective layer. Therefore, the near-infrared cut filter 100 of this embodiment has very little incidence angle dependency and is excellent in oblique incidence characteristics. In addition, the imaging device 1 using such a near-infrared cut filter 100 can obtain an image with excellent color reproducibility because the occurrence of ghosts is suppressed.

[0104] Although the embodiment of the present invention has been described above, the present invention is not limited to the configuration of the above embodiment, and various modifications are possible within the scope of the technical concept thereof.

[0105] For example, in the present embodiment (Examples 1 to 11), the near-infrared cut filter 100 is exemplified, in which the half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve is about 410 to 418 nm, and the half-value wavelength (NIR_λ50) on the long wavelength side is about 591 to 651 nm, but the characteristics are not limited to these. By appropriately selecting the ultraviolet absorbing dye and the near-infrared absorbing dye of the resin layer 102 and adjusting the mixing ratio thereof, the half-value wavelength on the short wavelength side of the transmittance curve can be adjusted within the range of 385 to 430 nm, and the half-value wavelength on the long wavelength side can be adjusted within the range of 590 to 670 nm.

[0106] Second embodiment Fig. 14 is a vertical cross-sectional view illustrating a configuration of a near-infrared cut filter 100A according to a second embodiment of the present invention. As shown in Fig. 14, the near-infrared cut filter 100A of this embodiment is different from the near-infrared cut filter 100 of the first embodiment in that it has an antireflection film 103 (first antireflection film) on the upper surface of the resin layer 102 (the surface opposite to the glass substrate 101) and an antireflection film 104 (second antireflection film) on the other main surface of the glass substrate 101 (the lower surface in Fig. 14). By forming the antireflection films 103 and 104 in this manner, reflection at the interfaces (that is, the entrance surface and exit surface) of the near-infrared cut filter 100A can be suppressed, and therefore the transmittance can be increased (improved).

[0107] The anti-reflection films 103 and 104 in this embodiment are layers that prevent reflection at the interfaces between the incident and exit surfaces of the near-infrared cut filter 100A, and specifically are composed of a dielectric multilayer film in which low refractive index dielectric films (low refractive index dielectric films) and high refractive index dielectric films (high refractive index dielectric films) are alternately stacked.

[0108] The material of the dielectric film constituting the dielectric multilayer film can be freely selected according to the desired optical properties. film The refractive index of the low refractive index material for constituting the present invention is preferably in the range of 1.1 to 1.5. Examples of the low refractive index material include SiO 2 , MgF 2 , SiO 2 Low refractive index sol-gel coatings with hollow cores or aerosol structures can be applied. film The refractive index of the high refractive index material for constituting the present invention is preferably in the range of 2.0 to 2.5. Examples of the high refractive index material include ZrO 2 , Ta 2 O 5 , TiO 2 , Nb 2 O 5 etc. can be applied. In addition, materials with a refractive index of 1.4 to 1.6 (e.g., SiO 2 ) can also be used as the high refractive index material, and in this case, a material with a refractive index of 1.1 to 1.3 (for example, aerosol coating) can be used as the low refractive index material.

[0109] In this way, 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 occurring in each dielectric film. However, when the number of film layers is increased, the optical path length becomes longer when the light is obliquely incident, and the interference condition of the reflected light in each layer is broken, which causes problems such as wavelength shift and ripple. In addition, such wavelength shift and ripple cause an increase in the reflected light, which is observed as a kind of ghost on the solid-state imaging element 200, and there is also a problem that accurate color reproducibility cannot be obtained. Therefore, in this embodiment, in order to avoid such problems, the number of film layers of the dielectric multilayer film is configured to be 10 layers or less. It is preferable that the number of film layers is particularly 5 layers or less, and more preferably 3 layers or less. Furthermore, the thickness of the dielectric films constituting the dielectric multilayer film can be freely selected depending on the desired optical properties, but is preferably 50 nm to 1 μm, and more preferably 50 nm to 500 nm. Moreover, the thickness of the entire dielectric multilayer film (that is, the antireflection films 103 and 104) is set to 500 nm or less.

[0110] In this embodiment, the resin layer 102 is formed on one main surface of the glass substrate 101 (the upper surface in FIG. 14), but similarly to the first embodiment, the resin layer 102 may be formed on the other main surface of the glass substrate 101 (the lower surface in FIG. 14), or may be formed on both surfaces of the glass substrate 101. In addition, the resin layer 102 does not necessarily have to be a single layer, and may be configured with multiple layers.

[0111] In this embodiment, the antireflection films 103 and 104 are provided, but the present invention is not limited to this configuration, and optical thin films having other functions, such as an infrared cut film and an ultraviolet cut film, may be used instead of the antireflection films 103 and 104. In other words, the near-infrared cut filter 100A according to this embodiment can be provided with an optical thin film having at least one of the functions of an antireflection film, an infrared cut film, and an ultraviolet cut film.

[0112] The near-infrared cut filter 100A of this embodiment will be further described below with reference to examples, but the present invention is not limited to the following examples.

[0113] Example 12 The near-infrared cut filter 100 of Example 1 is further formed with anti-reflection films 103 and 104 by the following procedure (3. Formation of anti-reflection films 103 and 104). 12 A near-infrared cut filter 100A was created.

[0114] [3. Formation of anti-reflection films 103 and 104] The dielectric thin films (dielectric layers 1 to 5) in Table 1 were formed in order (i.e., antireflection films 103 and 104) by the so-called sol-gel method on the upper surface (the surface opposite to the glass substrate 101) of the resin layer 102 of the near-infrared cut filter 100 of Example 1 and on the other main surface (the lower surface in FIG. 14) of the glass substrate 101. 12 Thus, a near-infrared cut filter 100A was obtained.

[0115] [Table 1]

[0116] Fig. 15 is a diagram showing the spectral transmittance curve of the near-infrared cut filter 100A of Example 12, which shows the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°. As shown in Fig. 15, the near-infrared cut filter 100A of this example has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 411 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of about 596 nm, and an average transmittance of 0.3% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100A was 3 nm. Furthermore, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the anti-reflection films 103 and 104, the thickness thereof is sufficiently thin (500 nm or less), so that even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance as a cut filter is suppressed. Furthermore, since the near-infrared cut filter 100A of this embodiment has anti-reflection films 103 and 104, it has a higher transmittance than the near-infrared cut filter 100 of Example 1 (i.e., compared to Figure 3), with the peak transmittance being approximately 98%.

[0117] Example 13 The antireflection films 103 and 104 were formed on the near-infrared cut filter 100 of Example 2 in the same manner as in Example 12 to prepare a near-infrared cut filter 100A of Example 13.

[0118] Fig. 16 is a diagram showing the spectral transmittance curve of the near-infrared cut filter 100A of Example 13, which shows the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°. As shown in Fig. 16, the near-infrared cut filter 100A of this example has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 410 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of about 605 nm, and an average transmittance of 0.6% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100A was 1 nm. Furthermore, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the anti-reflection films 103 and 104, the thickness thereof is sufficiently thin (500 nm or less), so that even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance as a cut filter is suppressed. Furthermore, since the near-infrared cut filter 100A of this embodiment has anti-reflection films 103 and 104, it has a higher transmittance than the near-infrared cut filter 100 of Example 2 (i.e., compared to Figure 4), with the peak transmittance being approximately 97%.

[0119] Example 14 The antireflection films 103 and 104 were formed on the near-infrared cut filter 100 of Example 3 in the same manner as in Example 12, to prepare a near-infrared cut filter 100A of Example 14.

[0120] Fig. 17 is a diagram showing the spectral transmittance curve of the near-infrared cut filter 100A of Example 14, which shows the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°. As shown in Fig. 17, the near-infrared cut filter 100A of this example has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 410 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of about 615 nm, and an average transmittance of 0.03% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100A was 7 nm. Furthermore, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the anti-reflection films 103 and 104, the thickness thereof is sufficiently thin (500 nm or less), so that even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance as a cut filter is suppressed. Furthermore, since the near-infrared cut filter 100A of this embodiment has anti-reflection films 103 and 104, it has a higher transmittance than the near-infrared cut filter 100 of Example 3 (i.e., compared to Figure 5), with the peak transmittance being approximately 97%.

[0121] Example 15 The antireflection films 103 and 104 were formed on the near-infrared cut filter 100 of Example 4 in the same manner as in Example 12 to prepare a near-infrared cut filter 100A of Example 15.

[0122] Fig. 18 is a diagram showing the spectral transmittance curve of the near-infrared cut filter 100A of Example 15, which shows the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°. As shown in Fig. 18, the near-infrared cut filter 100A of this example has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 409 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of about 625 nm, and an average transmittance of 0.07% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100A was 3 nm. Furthermore, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the anti-reflection films 103 and 104, the thickness thereof is sufficiently thin (500 nm or less), so that even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance as a cut filter is suppressed. Furthermore, since the near-infrared cut filter 100A of this embodiment has anti-reflection films 103 and 104, it has a higher transmittance than the near-infrared cut filter 100 of Example 4 (i.e., compared to Figure 6), with the peak transmittance being approximately 97%.

[0123] Example 16 The near-infrared cut filter 100 of Example 5 was formed with antireflection films 103 and 104 in the same manner as in Example 12 to prepare a near-infrared cut filter 100A of Example 16.

[0124] Fig. 19 is a diagram showing the spectral transmittance curve of the near-infrared cut filter 100A of Example 16, which shows the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°. As shown in Fig. 19, the near-infrared cut filter 100A of this example has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 410 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of about 625 nm, and an average transmittance of 0.09% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long-wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long-wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100A was 4 nm. Furthermore, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the anti-reflection films 103 and 104, the thickness thereof is sufficiently thin (500 nm or less), so that even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance as a cut filter is suppressed. Furthermore, since the near-infrared cut filter 100A of this embodiment has anti-reflection films 103 and 104, it has a higher transmittance than the near-infrared cut filter 100 of Example 5 (i.e., compared to Figure 7), with the peak transmittance being approximately 98%.

[0125] (Example 17) The antireflection films 103 and 104 were formed on the near-infrared cut filter 100 of Example 6 in the same manner as in Example 12 to prepare a near-infrared cut filter 100A of Example 17.

[0126] Fig. 20 is a diagram showing the spectral transmittance curve of the near-infrared cut filter 100A of Example 17, which shows the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°. As shown in Fig. 20, the near-infrared cut filter 100A of this example has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 409 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of about 630 nm, and an average transmittance of 0.2% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100A was 3 nm. Furthermore, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the anti-reflection films 103 and 104, the thickness thereof is sufficiently thin (500 nm or less), so that even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance as a cut filter is suppressed. Furthermore, since the near-infrared cut filter 100A of this embodiment has anti-reflection films 103 and 104, it has a higher transmittance than the near-infrared cut filter 100 of Example 6 (i.e., compared to Figure 8), with the peak transmittance being approximately 98%.

[0127] (Example 18) The near-infrared cut filter 100 of Example 7 was formed with antireflection films 103 and 104 in the same manner as in Example 12 to prepare a near-infrared cut filter 100A of Example 18.

[0128] Fig. 21 is a diagram showing the spectral transmittance curve of the near-infrared cut filter 100A of Example 18, which shows the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°. As shown in Fig. 21, the near-infrared cut filter 100A of this example has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 414 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of about 630 nm, and an average transmittance of 0.2% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long-wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long-wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100A was 6 nm. Furthermore, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the anti-reflection films 103 and 104, the thickness thereof is sufficiently thin (500 nm or less), so that even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance as a cut filter is suppressed. Furthermore, since the near-infrared cut filter 100A of this embodiment has anti-reflection films 103 and 104, it has a higher transmittance than the near-infrared cut filter 100 of Example 7 (i.e., compared to Figure 9), with the peak transmittance being approximately 95%.

[0129] (Example 19) The near-infrared cut filter 100 of Example 8 was formed with antireflection films 103 and 104 in the same manner as in Example 12 to prepare a near-infrared cut filter 100A of Example 19.

[0130] Fig. 22 is a diagram showing the spectral transmittance curve of the near-infrared cut filter 100A of Example 19, which shows the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°. As shown in Fig. 22, the near-infrared cut filter 100A of this example has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 410 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of about 635 nm, and an average transmittance of 0.2% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100A was 1 nm. Furthermore, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the anti-reflection films 103 and 104, the thickness thereof is sufficiently thin (500 nm or less), so that even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance as a cut filter is suppressed. Furthermore, since the near-infrared cut filter 100A of this embodiment has anti-reflection films 103 and 104, it has a higher transmittance than the near-infrared cut filter 100 of Example 8 (i.e., compared to Figure 10), with the peak transmittance being approximately 97%.

[0131] (Example 20) The near-infrared cut filter 100 of Example 9 was formed with antireflection films 103 and 104 in the same manner as in Example 12 to prepare a near-infrared cut filter 100A of Example 20.

[0132] Fig. 23 is a diagram showing the spectral transmittance curve of the near-infrared cut filter 100A of Example 20, which shows the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°. As shown in Fig. 23, the near-infrared cut filter 100A of this example has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 409 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of about 651 nm, and an average transmittance of 0.8% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long-wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long-wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100A was 4 nm. Furthermore, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the anti-reflection films 103 and 104, the thickness thereof is sufficiently thin (500 nm or less), so that even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance as a cut filter is suppressed. Furthermore, since the near-infrared cut filter 100A of this embodiment has anti-reflection films 103 and 104, it has a higher transmittance than the near-infrared cut filter 100 of Example 9 (i.e., compared to FIG. 11), with the peak transmittance being approximately 98%.

[0133] Example 21 The near-infrared cut filter 100 of Example 10 was formed with antireflection films 103 and 104 in the same manner as in Example 12 to prepare a near-infrared cut filter 100A of Example 21.

[0134] Fig. 24 is a diagram showing the spectral transmittance curve of the near-infrared cut filter 100A of Example 21, which shows the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°. As shown in Fig. 24, the near-infrared cut filter 100A of this example has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 408 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of about 656 nm, and an average transmittance of 1.3% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long-wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long-wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100A was 5 nm. Furthermore, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the anti-reflection films 103 and 104, the thickness thereof is sufficiently thin (500 nm or less), so that even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance as a cut filter is suppressed. Furthermore, since the near-infrared cut filter 100A of this embodiment has anti-reflection films 103 and 104, it has a higher transmittance than the near-infrared cut filter 100 of Example 10 (i.e., compared to Figure 12), with the peak transmittance being approximately 98%.

[0135] Example 22 The near-infrared cut filter 100 of Example 11 was formed with antireflection films 103 and 104 in the same manner as in Example 12 to prepare a near-infrared cut filter 100A of Example 22.

[0136] Fig. 25 is a diagram showing the spectral transmittance curve of the near-infrared cut filter 100A of Example 22, which shows the spectral transmittance curve (solid line) when the incident angle is 0° and the spectral transmittance curve (dashed line) when the incident angle is 30°. As shown in Fig. 25, the near-infrared cut filter 100A of this example has a half-value wavelength (UV_λ50) on the short wavelength side of the transmittance curve of about 409 nm, a half-value wavelength (NIR_λ50) on the long wavelength side of the transmittance curve of about 657 nm, and an average transmittance of 1.7% in the wavelength range of 800 to 1100 nm, which is close to the visual sensitivity of humans. In this embodiment, the difference between the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the glass substrate 101 and the long wavelength half-value wavelength (NIR_λ50) of the transmittance curve of the near-infrared cut filter 100A was 1 nm. Furthermore, although the near-infrared cut filter 100A of this embodiment has a dielectric multilayer film as the anti-reflection films 103 and 104, the thickness thereof is sufficiently thin (500 nm or less), so that even when light with an incident angle of 30° is incident, the occurrence of phase shift, wavelength shift, and ripple that significantly impair the performance as a cut filter is suppressed. Furthermore, since the near-infrared cut filter 100A of this embodiment has anti-reflection films 103 and 104, it has a higher transmittance than the near-infrared cut filter 100 of Example 11 (i.e., compared to Figure 13), with the peak transmittance being approximately 98%.

[0137] In this way, the near-infrared cut filters 100A of Examples 12 to 22 have excellent oblique incidence characteristics and high transmittance. A The imaging device 1 using this can obtain bright images with excellent color reproducibility.

[0138] (Third embodiment) Fig. 26 is a vertical cross-sectional view illustrating a configuration of a near-infrared cut filter 100B according to a third embodiment of the present invention. As shown in Fig. 26, the near-infrared cut filter 100B of this embodiment differs from the near-infrared cut filter 100 of the first embodiment in that a bonding layer 105 that bonds a glass substrate 101 and a resin layer 102 to each other is provided between the glass substrate 101 and the resin layer 102. By forming the bonding layer 105 in this manner, the adhesion between the glass substrate 101 and the resin layer 102 can be increased, leading to improved reliability.

[0139] As a result of intensive research, the present inventors have found that the use of a bonding component containing Si atoms and one or more atoms selected from Ti atoms, Zr atoms, and Al atoms can improve the adhesion between the glass substrate 101 and the resin layer 102. The bonding layer 105 of the present embodiment is based on this finding, and has a single layer structure containing Si atoms and one or more atoms selected from Ti atoms, Zr atoms, and Al atoms. In this specification, the single layer structure means a layer structure that is identified as being made of forming materials having the same composition from the measurement image (image contrast) or elemental analysis results obtained when measured with a scanning transmission electron microscope-energy dispersive X-ray spectrometer (STEM-EDX) under the measurement conditions described below. <Measurement conditions> Scanning transmission electron microscope: JEOL Ltd. ARM200F Energy dispersive X-ray spectrometer: JED-2300T manufactured by JEOL Ltd. Sample preparation: Focused ion beam processing (FIB) Accelerating voltage: 200 kV Elemental analysis: EDX mapping (resolution: 256 x 256)

[0140] The thickness of the bonding layer 105 is preferably 1000 nm or less, more preferably 10 to 500 nm, and further preferably 30 to 300 nm. By making the thickness of the bonding layer 105 1000 nm or less, the occurrence of unevenness during the formation (firing) of the bonding layer 105 can be easily suppressed, and the film surface of the bonding layer 105 can be easily made uniform. Furthermore, 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 this specification, the thickness of the bonding layer 105 means the arithmetic average value when the thickness of the bonding layer 105 is measured at 50 points in a measurement image (image contrast) of the cross section of the near-infrared cut filter 100B obtained by measurement using the above-mentioned STEM-EDX.

[0141] The bonding layer 105 of this embodiment contains one or more atoms selected from Ti atoms, Zr atoms, and Al atoms in addition to Si atoms. However, it is preferable that the one or more atoms selected from Ti atoms, Zr atoms, and Al atoms contained in the bonding layer 105 together with Si atoms are Ti atoms.

[0142] 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 (total atomic number) of Si atoms, Ti atoms, Zr atoms, and Al atoms is preferably more than 0 atomic% and not more than 50 atomic%, more preferably 9 to 50 atomic%, and even more preferably 12 to 50 atomic%. In this specification, the ratio α (atomic%) of the total number of Ti atoms, Zr atoms, and Al atoms to the total number (total atomic number) of Si atoms, Ti atoms, Zr atoms, and Al atoms constituting the bonding layer 105 means a value calculated by the following method. (1) STEM-EDX measurement of the optical filter is performed under the above-mentioned measurement conditions to obtain STEM-EDX lines (EDX ray (K ray) detection intensity lines in the depth direction of each element constituting the optical filter). (2) EDX ray integrated intensity X of Si atoms in the region constituting the bonding layer 105 Si , the integrated EDX line intensity of Ti atom X Ti, the integrated EDX line intensity of Zr atom X Zr and the integrated EDX line intensity X of Al atoms Al We ask for the following respectively. (3) Each EDX line integrated intensity obtained in (2) is multiplied by the k-factor (a correction coefficient that depends on the accelerating voltage and detection efficiency and differs depending on the atomic number. For the sake of convenience, the k-factor of the Si atom is defined as K Si , the k-factor of Ti atom is K Ti , the k-factor of Zr atom is K Zr , the k-factor of the Al atom is K Al The weight ratio A of the Ti atoms constituting the bonding layer can be considered to correspond to the weight ratio of each constituent element. Ti (% by weight) can be calculated by the following formula.

number

number

number

number

[0143] The near-infrared cut filter 100B of this embodiment will be further described below with reference to examples, but the present invention is not limited to the following examples.

[0144] Example 23 The bonding layer 105 was formed on the glass substrate 101 of Example 1 by the following procedure (4. Formation of 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 resin layer 102), to produce a near-infrared cut filter 100B.

[0145] [4. Formation of bonding layer 105] 1. Preparation of coating solution containing coupling agent (1) 0.3 mL of 0.5 N (mol / L) HCl aqueous solution and 2.2 mL of 2-methoxyethanol were weighed into a container and mixed in a sealed container. (2) Tetraethyl orthosilicate (Si(OC 2 H 5 ) 4 ) was added and mixed in a sealed state for 30 minutes to cause the 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 Because the above reaction consumes all water and produces hydroxyl groups, it was expected that even if Ti alkoxide, which has a fast hydrolysis rate, was added, hydroxide would not precipitate and the solution would become homogeneous. (3) Add titanium(IV) n-butoxide (Ti(OC 4 H 9 ) 4 ) was added in a prescribed ratio (for example, 3 to 20 mol %) and mixed for 30 minutes in a sealed state to prepare a coupling agent-containing coating liquid. At this time, it is believed that the reaction represented by the following reaction formula occurred inside 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

[0146] 2. Formation of coating film Into the container containing the coupling agent-containing coating liquid, 1.2 mL of 0.5N HCl aqueous solution, 4.7 mL of water, and 8.1 mL of 2-methoxyethanol were further weighed and mixed for 30 minutes in a sealed state to prepare a coating film-forming liquid. At this time, it is believed that the reaction represented by the following reaction formula occurred inside 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 be 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 to cause dehydration and condensation, thereby forming a cured film (bonding layer 105) on the surface.

[0147] Next, the resin layer 102 was formed on the upper surface of the bonding layer 105 in the same manner as in Example 1 (2. Formation of the resin layer 102), thereby completing the near-infrared cut filter 100B.

[0148] In this way, by forming the bonding layer 105 between the glass substrate 101 and the resin layer 102, the adhesion between the glass substrate 101 and the resin layer 102 can be significantly increased, thereby dramatically improving reliability.

[0149] In addition, the bonding layer 105 of the present embodiment contains one or more atoms selected from Ti atoms, Zr atoms, and Al atoms, as well as Si atoms, but instead of forming the bonding layer 105, each component of the bonding layer 105 can be contained in the resin layer 102. That is, the resin layer 102 can be configured to contain one or more atoms selected from Ti atoms, Zr atoms, and Al atoms, as well as Si atoms.

[0150] In addition, the bonding layer 105 of the present embodiment contains one or more atoms selected from Ti atoms, Zr atoms, and Al atoms, as well as Si atoms. However, any material that can enhance the adhesion between the glass substrate 101 and the resin layer 102 may be used, and for example, a transparent vapor deposition or coating type adhesive may be used.

[0151] Furthermore, the resin layer 102 in this embodiment is formed on one main surface (the upper surface in FIG. 26) of the glass base material 101 via the bonding layer 105, but similarly to the first embodiment, the resin layer 102 may be formed on the other main surface (the lower surface in FIG. 26) of the glass base material 101 via the bonding layer 105, or may be formed on both surfaces of the glass base material 101. Furthermore, the resin layer 102 does not necessarily have to be a single layer, and may be configured with multiple layers.

[0152] Although the bonding layer 105 in this embodiment is used for the purpose of bonding the glass substrate 101 and the resin layer 102, it can also be used as a protective layer (AD (Anti-Dimming) coat) that protects the glass substrate 101.

[0153] (Example 24) Fig. 27 shows an example in which the bonding layer 105 of this embodiment is applied to a protective layer 107 (AD). As shown in Fig. 27, in this example, the protective layer 107, the resin layer 102, and the anti-reflection film 103 are formed in this order on one main surface of the glass substrate 101, and the protective layer 107 is formed on the other main surface. In this manner, in this embodiment, since the protective layers 107 are formed on both main surfaces of the glass base material 101, deterioration (such as discoloration) of the glass base material 101 is prevented.

[0154] (Example 25) FIG. 28 shows an anti-reflection film 104 further formed on the lower protective layer 107 (on the other main surface) shown in FIG. As described above, in this embodiment, since the anti-reflection film 104 is further formed on the protective layer 107, reflection at the interfaces (i.e., the incident surface and the exit surface) can be suppressed, and the transmittance can be increased (improved).

[0155] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0156] 1: Imaging device 11: Absorption layer 12: Reflective layer 13: Transparent base material 100: Near infrared cut filter 100A: Near infrared cut filter 100B: Near infrared cut filter 101: Glass substrate 102: Resin layer 103: Anti-reflection coating 104: Anti-reflection coating 105: Bonding layer 107 :Protective layer 200: Solid-state imaging element 300:Package

Claims

1. A near-infrared cut filter comprising: a transparent substrate having a thickness of 0.16 to 0.26 mm and an average transmittance of 1% or less in a wavelength range of 800 to 1100 nm; and a resin layer formed on at least one main surface of the transparent substrate and absorbing light of a specific wavelength.

2. The near-infrared cut filter according to claim 1, wherein a half-value wavelength on the short wavelength side of the transmittance curve of the transparent substrate is 300 to 400 nm, and a half-value wavelength on the long wavelength side is 590 to 670 nm.

3. The near-infrared cut filter according to claim 1 or 2, wherein the transparent substrate has an average transmittance of 40% or less in a wavelength range of 650 to 720 nm.

4. The near-infrared cut filter according to any one of claims 1 to 3, wherein the transparent substrate has an average transmittance of 15% or less in a wavelength range of 720 to 750 nm.

5. The near-infrared cut filter according to any one of claims 1 to 4, wherein the transparent substrate has an average transmittance of 5% or less in a wavelength range of 800 to 1200 nm.

6. The near-infrared cut filter according to any one of claims 1 to 5, wherein the resin layer contains a transparent resin and a dye uniformly dispersed in the transparent resin.

7. The near-infrared cut filter according to claim 6, wherein the dye contains an ultraviolet absorbing dye having a maximum absorption wavelength at 340 to 400 nm.

8. The near-infrared cut filter according to claim 6 or 7, wherein the dye contains a near-infrared absorbing dye having a maximum absorption wavelength at 650 to 900 nm.

9. The near-infrared cut filter according to any one of claims 1 to 8, wherein the resin layer contains Si atoms as essential components and contains one or more selected from Ti atoms, Zr atoms, and Al atoms as optional components.

10. The near-infrared cut filter according to any one of claims 1 to 9, further comprising an adhesive layer between the transparent substrate and the resin layer to enhance the adhesion between the transparent substrate and the resin layer.

11. The near-infrared cut filter according to claim 10, further comprising the bonding layer on the other main surface of the transparent substrate.

12. The near-infrared cut filter according to claim 10 or claim 11, wherein the bonding layer has a single-layer structure containing at least one selected from Ti atoms, Zr atoms, and Al atoms together with Si atoms.

13. The near-infrared cut filter according to claim 12, wherein in the bonding layer, the ratio 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 is more than 0 atomic % and 50 atomic % or less.

14. The near-infrared cut filter according to any one of claims 1 to 13, comprising a first functional film on the resin layer and a second functional film on the other main surface of the transparent substrate.

15. The near-infrared cut filter according to claim 14, wherein the first functional film and the second functional film are optical thin films having at least one function of an antireflection film, an infrared cut film, and an ultraviolet cut film.

16. The near-infrared cut filter according to claim 15, wherein the first functional film and the second functional film are each composed of a dielectric multilayer film having a thickness of 500 nm or less.

17. The near-infrared cut filter according to claim 16, wherein the dielectric multilayer film has 10 layers or less.

18. The near-infrared cut filter according to claim 16 or claim 17, wherein the dielectric multilayer film is formed by alternately laminating a low-refractive-index dielectric film composed of a material having a refractive index of 1.1 to 1.5 and a high-refractive-index dielectric film composed of a material having a refractive index of 2.0 to 2.

5.

19. The near-infrared cut filter according to claim 16 or claim 17, wherein the dielectric multilayer film is formed by alternately laminating a low-refractive-index dielectric film composed of a material having a refractive index of 1.1 to 1.3 and a high-refractive-index dielectric film composed of a material having a refractive index of 1.4 to 1.

6.

20. The near-infrared cut filter according to any one of claims 1 to 19, characterized in 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 of the transmittance curve is 590 to 660 nm.

21. The near-infrared cut filter according to any one of claims 1 to 20, characterized in that the difference between the half-value wavelength on the long-wavelength side of the transmittance curve of the transparent substrate and the half-value wavelength on the long-wavelength side of the transmittance curve of the near-infrared cut filter is 20 nm or less.

22. The near-infrared cut filter according to any one of claims 1 to 21, characterized in that the transparent substrate is made of fluorophosphate glass or phosphate glass.

23. An imaging device comprising a solid-state imaging device and the near-infrared cut filter according to any one of claims 1 to 22.

24. The imaging device according to claim 23, characterized in that the near-infrared cut filter is disposed immediately in front of the solid-state imaging device and also serves as a cover glass.

Images