JP2019109526A - Infrared cut filter, imaging apparatus and method of manufacturing infrared cut filter - Google Patents

Abstract

To provide an infrared cut filter having good infrared cutoff characteristics with little dependency on an incident angle.SOLUTION: An infrared cut filter 10 comprises: a transparent dielectric substrate 12; an infrared reflection layer 14 reflecting infrared and formed on one surface of the transparent dielectric substrate 12; and an infrared absorption layer 16 absorbing infrared and formed on the other surface of the transparent dielectric substrate 12. The infrared absorption layer 16 is formed from resin containing an infrared absorbing dye. The infrared reflection layer 14 is formed from a dielectric multilayer film.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an infrared cut filter and an imaging device using the infrared cut filter.

  A solid-state solid-state imaging device such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) is mounted on an imaging device such as a digital camera. The sensitivity of these solid-state imaging devices ranges from the visible region to the infrared region. Therefore, in the imaging device, an infrared cut filter for blocking infrared rays is provided between the imaging lens and the solid-state imaging device. With this infrared cut filter, the sensitivity of the solid-state imaging device can be corrected so as to approach human visibility.

  Conventionally, as such an infrared cut filter, what formed the infrared reflective layer which consists of a dielectric multilayer film in resin-made board | substrates is known (for example, refer patent document 1).

JP 2005-338395 A

  However, since the infrared reflection layer formed of the dielectric multilayer film has incident angle dependency that the infrared ray blocking property changes depending on the incident angle, when light transmitted through the infrared reflection layer is imaged, the central portion and the periphery of the image There is a possibility that color differences may occur between parts.

  The present invention has been made in view of these circumstances, and an object thereof is to provide an infrared cut filter having a good infrared ray blocking characteristic with small incident angle dependency, and an imaging device using the infrared cut filter. .

  In order to solve the above problems, an infrared cut filter according to an aspect of the present invention comprises a transparent dielectric substrate, an infrared reflection layer reflecting infrared radiation formed on one surface of the transparent dielectric substrate, and a transparent dielectric And an infrared absorbing layer for absorbing infrared rays formed on the other side of the substrate.

  The infrared absorbing layer may be formed of a resin containing an infrared absorbing dye.

  The infrared reflection layer may be formed of a dielectric multilayer film.

_Assuming that the wavelength at which the transmittance of the infrared reflection layer is 50% is λ _{RT 50%} nm, and the wavelength at which the transmittance of the infrared absorption layer is 50% is λ _AT 50 _% nm, λ _{AT 50%} <λ _{RT 50%} is satisfied. As such, an infrared reflection layer and an infrared absorption layer may be formed.

Infrared reflective layer and the infrared-absorbing layer may be formed so as to satisfy the more _{λ AT50% -λ RT50% ≦ -10nm} .

Further, the infrared reflection layer and the infrared absorption layer may be formed so as to satisfy ₋₅₀ nm ≦ λ _{AT 50 %} −λ _{RT 50%} .

  The transparent dielectric substrate may be formed of glass. The infrared reflective layer may be formed to reflect ultraviolet light. A protective layer may further be provided on the infrared absorption layer. The protective layer may have a function of preventing reflection of visible light. The protective layer may have a function of preventing transmission of ultraviolet light. The protective layer may further include an antireflective layer that prevents reflection of visible light. The antireflective layer may have a function of preventing transmission of ultraviolet light. It may further comprise a primer layer between the transparent dielectric substrate and the infrared absorbing layer.

  The infrared reflective layer may be warped such that the surface facing the surface on the transparent dielectric substrate side is convex.

  Another aspect of the present invention is an imaging device. The apparatus includes the infrared cut filter, and an imaging element on which light transmitted through the infrared cut filter is incident.

  It is to be noted that any combination of the above-described components, and a conversion of the expression of the present invention among methods, apparatuses, systems, and the like are also effective as an aspect of the present invention.

  According to the present invention, it is possible to provide an infrared cut filter having good infrared blocking characteristics with small incident angle dependency, and an imaging device using the infrared cut filter.

It is a sectional view for explaining the composition of the infrared cut filter concerning the embodiment of the present invention. An example of the spectral transmission factor curve of the infrared reflectiveness layer which consists of a dielectric multilayer film which concerns on a 1st comparative example is shown. An example of the spectral transmission factor curve which consists of an infrared rays absorption layer concerning a 2nd comparative example is shown. An example of the spectral transmission factor curve of the infrared cut filter which concerns on this embodiment is shown. It is a figure which shows a composition of the infrared rays absorption layer used for the 1st-3rd Example. It is a diagram showing a spectral transmittance of the infrared cut filter when the _{AT50% -λ RT50%} = 60nm _λ in the first embodiment. It is a diagram showing a spectral transmittance of the infrared cut filter when the _{AT50% -λ RT50%} = 50nm _λ in the first embodiment. Is a diagram showing a spectral transmittance curve of the infrared cut filter when the _{AT50% -λ RT50%} = 40nm _λ in the first embodiment. Is a diagram showing a spectral transmittance curve of the infrared cut filter when the _{AT50% -λ RT50%} = 30nm _λ in the first embodiment. Is a diagram showing a spectral transmittance curve of the infrared cut filter when the _{AT50% -λ RT50%} = 20nm _λ in the first embodiment. Is a diagram showing a spectral transmittance curve of the infrared cut filter when the _{AT50% -λ RT50%} = 10nm _λ in the first embodiment. Λ _AT50% -λ _RT50% in the first embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the 0 nm. Λ _AT50% -λ _RT50% in the first embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the -10 nm. Λ _AT50% -λ _RT50% in the first embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the -20 nm. Λ _AT50% -λ _RT50% in the first embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the -30 nm. Λ _AT50% -λ _RT50% in the first embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the -40 nm. Λ _AT50% -λ _RT50% in the first embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the -50 nm. Λ _AT50% -λ _RT50% in the first embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the -60 nm. It is a diagram showing a spectral transmittance of the infrared cut filter when the _{AT50% -λ RT50%} = 60nm _λ in the second embodiment. It is a diagram showing a spectral transmittance of the infrared cut filter when the _{AT50% -λ RT50%} = 50nm _λ in the second embodiment. Is a diagram showing a spectral transmittance curve of the infrared cut filter when the _{AT50% -λ RT50%} = 40nm _λ in the second embodiment. Is a diagram showing a spectral transmittance curve of the infrared cut filter when the _{AT50% -λ RT50%} = 30nm _λ in the second embodiment. Is a diagram showing a spectral transmittance curve of the infrared cut filter when the _{AT50% -λ RT50%} = 20nm _λ in the second embodiment. Is a diagram showing a spectral transmittance curve of the infrared cut filter when the _{AT50% -λ RT50%} = 10nm _λ in the second embodiment. Λ _AT50% -λ _RT50% in the second embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the 0 nm. Λ _AT50% -λ _RT50% in the second embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the -10 nm. Λ _AT50% -λ _RT50% in the second embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the -20 nm. Λ _AT50% -λ _RT50% in the second embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the -30 nm. Λ _AT50% -λ _RT50% in the second embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the -40 nm. Λ _AT50% -λ _RT50% in the second embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the -50 nm. Λ _AT50% -λ _RT50% in the second embodiment = a diagram showing a spectral transmittance curve of the infrared cut filter when the -60 nm. It is a diagram showing a spectral transmittance of the infrared cut filter when the _{AT50% -λ RT50%} = 60nm _λ in the third embodiment. It is a diagram showing a spectral transmittance of the infrared cut filter when the _{AT50% -λ RT50%} = 50nm _λ in the third embodiment. 3 is a diagram showing a spectral transmittance curve of the infrared cut filter when the _{AT50% -λ RT50%} = 40nm _λ in Example. 3 is a diagram showing a spectral transmittance curve of the infrared cut filter when the _{AT50% -λ RT50%} = 30nm _λ in Example. 3 is a diagram showing a spectral transmittance curve of the infrared cut filter when the _{AT50% -λ RT50%} = 20nm _λ in Example. 3 is a diagram showing a spectral transmittance curve of the infrared cut filter when the _{AT50% -λ RT50%} = 10nm _λ in Example. The 3 lambda in Example _{AT50% -λ RT50%} = a diagram showing a spectral transmittance curve of the infrared cut filter when the 0 nm. The 3 lambda in Example _{AT50% -λ RT50%} = a diagram showing a spectral transmittance curve of the infrared cut filter when the -10 nm. The 3 lambda in Example _{AT50% -λ RT50%} = a diagram showing a spectral transmittance curve of the infrared cut filter when the -20 nm. The 3 lambda in Example _{AT50% -λ RT50%} = a diagram showing a spectral transmittance curve of the infrared cut filter when the -30 nm. The 3 lambda in Example _{AT50% -λ RT50%} = a diagram showing a spectral transmittance curve of the infrared cut filter when the -40 nm. The 3 lambda in Example _{AT50% -λ RT50%} = a diagram showing a spectral transmittance curve of the infrared cut filter when the -50 nm. The 3 lambda in Example _{AT50% -λ RT50%} = a diagram showing a spectral transmittance curve of the infrared cut filter when the -60 nm. It is a figure which shows the table which put together the main parameters of the spectral transmission factor curve shown in Drawing 6 (a)-(m). It is a figure which shows the table | surface which put together the main parameters of the spectral transmission factor curve shown to Fig.7 (a)-(m). It is a figure which shows the table | surface which put together the main parameters of the spectral transmission factor curve shown to FIG. 8 (a)-(m). It is a figure which shows the relationship between the difference of the cutoff wavelength of the infrared rays absorption layer in 1st Example, the cutoff wavelength of an infrared reflectiveness layer, and the steepness degree of the transient area | region of a spectral transmission factor curve. The figure which shows the relationship between the difference of the cutoff wavelength of the infrared rays absorption layer in Example 1 and the cutoff wavelength of an infrared reflectiveness layer, and the shift amount of the cutoff wavelength when an incident angle changes from 0 degree to 35 degrees. is there. It is a figure which shows the relationship between the difference of the cutoff wavelength of the infrared rays absorption layer in 2nd Example, and the cutoff wavelength of an infrared reflectiveness layer, and the steepness of the transient area | region of a spectral transmission factor curve. The figure which shows the relationship between the difference of the cutoff wavelength of the infrared rays absorption layer in Example 2 and the cutoff wavelength of an infrared reflectiveness layer, and the shift amount of the cutoff wavelength when an incident angle changes from 0 degree to 35 degrees. is there. It is a figure which shows the relationship between the difference of the cutoff wavelength of the infrared rays absorption layer in 3rd Example, and the cutoff wavelength of an infrared reflectiveness layer, and the steepness degree of the transient area | region of a spectral transmission factor curve. The figure which shows the relationship between the difference of the cutoff wavelength of the infrared absorption layer in 3rd Example, and the cutoff wavelength of an infrared reflectiveness layer, and the shift amount of the cutoff wavelength when an incident angle changes from 0 degree to 35 degrees. is there. It is a figure which shows the infrared cut filter which concerns on another embodiment of this invention. It is a figure which shows the infrared cut filter which concerns on another embodiment of this invention. It is a figure which shows the infrared cut filter which concerns on another embodiment of this invention. It is a figure which shows the infrared cut filter which concerns on another embodiment of this invention. It is a figure for demonstrating the imaging device using the infrared cut filter which concerns on embodiment of this invention. It is a figure which shows a spectral transmission factor curve when changing the cutoff wavelength of an infrared reflectiveness layer. The spectral transmission factor curve of the infrared rays absorption layer single-piece used in the 1st example is shown. The spectral transmission factor curve of the infrared absorption layer single-piece | unit used in 2nd Example is shown. The spectral transmission factor curve of the infrared rays absorption layer single-piece | unit used in 3rd Example is shown.

  FIG. 1 is a cross-sectional view for explaining the configuration of an infrared cut filter 10 according to an embodiment of the present invention. As shown in FIG. 1, the infrared cut filter 10 includes a transparent dielectric substrate 12, an infrared reflection layer 14, and an infrared absorption layer 16. The infrared reflective layer 14 is formed on one surface of the transparent dielectric substrate 12. The infrared absorbing layer 16 is formed on the other surface of the transparent dielectric substrate 12.

  For example, in a digital camera, the infrared cut filter 10 shown in FIG. 1 is provided between an imaging lens and an imaging element. The infrared cut filter 10 is mounted so as to receive light from the infrared reflection layer 14 and emit light from the infrared absorption layer 16. That is, in the mounted state, the infrared reflection layer 14 faces the imaging lens, and the infrared absorption layer 16 faces the imaging element.

  The transparent dielectric substrate 12 may be, for example, a plate-like body having a thickness of about 0.1 mm to 0.3 mm. The material constituting the transparent dielectric substrate 12 is not particularly limited as long as it transmits visible light, and may be, for example, glass. A glass substrate formed of glass is preferable from the viewpoint of cost because it is inexpensive. Alternatively, as the transparent dielectric substrate 12, a synthetic resin film or synthetic resin substrate such as PMMA (Polymethylmethacrylate), PET (Polyethylene terephthalate), PC (Polycarbonate), PI (Polyimide) or the like can be used.

The infrared reflective layer 14 is formed on one surface of the transparent dielectric substrate 12 as described above, and functions as a light incident surface. The infrared reflective layer 14 is configured to transmit visible light and reflect infrared light. The infrared reflective layer 14 may be formed of a dielectric multilayer film in which dielectrics having different refractive indexes are stacked in multiple layers. The dielectric multilayer film can freely design optical characteristics such as spectral transmittance characteristics by controlling the refractive index and the layer thickness of each layer. The infrared reflective layer 14 may be, for example, one obtained by alternately depositing a titanium oxide (TiO ₂ ) layer and a silicon oxide (SiO ₂ ) layer having different refractive indexes on the transparent dielectric substrate 12. Besides TiO ₂ and SiO ₂ , dielectrics such as MgF ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , Nb ₂ O ₅ and Ta ₂ O ₅ can also be used as the material of the dielectric multilayer film.

  The infrared absorbing layer 16 is formed on the other surface of the transparent dielectric substrate 12 as described above, and functions as a light emitting surface. The infrared absorbing layer 16 is configured to transmit visible light and to absorb infrared light. The light incident on the infrared cut filter 10 is transmitted through the infrared reflection layer 14 and the transparent dielectric substrate 12 and then incident on the infrared absorption layer 16. Therefore, the infrared absorption layer 16 includes the infrared reflection layer 14 and the transparent dielectric substrate 12. Will absorb infrared rays that were not blocked.

  The infrared absorbing layer 16 may be formed by depositing a resin containing an infrared absorbing dye on the transparent dielectric substrate 12. The infrared absorbing layer 16 may be a solid film formed by adding a suitable infrared absorbing dye in a resin matrix, dissolving or dispersing it, drying and curing. As the infrared absorbing dye, an azo compound, a dimonium compound, a dithiol metal complex type, a phthalocyanine compound, a cyanine compound or the like can be used, and these may be used in combination. In addition, as the resin matrix, it is required to retain the dissolved or dispersed infrared absorbing dye and to be a transparent dielectric, and polyester, polyacrylic, polyolefin, polycarbonate, polycycloolefin, polyvinyl butyral or the like is used. Can. Since these resin matrices are inexpensive, they are preferable from the viewpoint of cost.

  Next, the operation of the infrared cut filter 10 according to the present embodiment will be described. First, the operation of the infrared cut filter according to the comparative example will be described.

  FIG. 2 shows, as a first comparative example, a spectral transmittance curve of an infrared cut filter in which only an infrared reflective layer made of a dielectric multilayer film is formed on a glass substrate. Further, FIG. 3 shows a spectral transmittance curve of an infrared cut filter in which only an infrared absorbing layer composed of a resin matrix containing an infrared absorbing dye is formed on a glass substrate as a second comparative example.

In the infrared cut filter according to the first comparative example, as shown in FIG. 2, the incident angle dependency of the blocking characteristic which is the feature of the dielectric multilayer film is observed. In FIG. 2, the solid line indicates the spectral transmittance curve when the incident angle is 0 °, the broken line indicates the spectral transmittance curve when the incident angle is 25 °, and the dashed dotted line indicates the spectrum when the incident angle is 35 ° The transmittance curve is shown. When transmittance and the wavelength at which _50% λ _RT50%, but when the incident angle is 0 ° is lambda _RT50% = about 655 nm, the incident angle is 25 ° λ _RT50% = about 637 nm, incident When the angle is 35 °, λ _{RT 50%} = about 625 nm. As described above, in the infrared cut filter according to the first comparative example, when the incident angle changes from 0 ° to 35 °, λ _{RT 50%} shifts to the short wavelength side by about 30 nm.

  When an infrared cut filter is applied to an imaging element, light having a small incident angle (for example, an incident angle of 0 °) to the infrared cut filter is usually incident on the central portion of the imaging element. In the peripheral portion, light having a large incident angle (for example, an incident angle of 25 ° or 35 °) to the infrared cut filter is incident. Therefore, when an infrared cut filter having an infrared blocking characteristic as shown in FIG. 2 is applied to an imaging device, the spectral transmittance curve characteristic of light incident on the imaging device (in particular, around 650 nm) depending on the position of the light receiving surface of the imaging device The spectral characteristics of This causes a phenomenon in which the tint differs between the central portion and the peripheral portion of the image, which may adversely affect the color reproducibility.

  Further, unlike the infrared cut filter according to the first comparative example, the infrared cut filter according to the second comparative example has no incident angle dependency of the blocking characteristic. However, as shown in FIG. 3, in the infrared cut filter according to the second comparative example, the spectral transmittance curve in the transition region where the transmittance changes from a relatively high region to a low region gradually falls. Generally, in the infrared cut filter, the transient region is provided in the vicinity of a wavelength of 600 nm to 700 nm so as not to affect the color reproducibility, and the transmittance in this region sharply changes ("sharp cut characteristics" Is called for). Therefore, in the infrared cut filter according to the second comparative example, it is difficult to satisfactorily realize control of color reproducibility.

  In consideration of the defects in these comparative examples, the inventor forms the infrared reflection layer 14 on one surface of the transparent dielectric substrate 12 and forms the infrared absorption layer 16 on the other surface to block the light. It has been found that the dependency of the characteristics on the incident angle is small and good sharp cut characteristics can be realized.

  FIG. 4 shows a spectral transmittance curve of the infrared cut filter 10 according to the present embodiment. Also in FIG. 4, the solid line indicates the spectral transmittance curve when the incident angle is 0 °, the broken line indicates the spectral transmittance curve when the incident angle is 25 °, and the dashed line indicates the spectrum when the incident angle is 35 ° The transmittance curve is shown.

The characteristics of the infrared cut filter 10 according to the present embodiment are determined by the combination of the optical characteristics of the infrared reflection layer 14 and the optical characteristics of the infrared absorption layer 16. Here, in the infrared reflection layer alone, the wavelength at which the transmittance is 50% at an incident angle of 0 ° is λ _{RT 50%} (nm), and in the infrared absorption layer alone, the wavelength at which the transmittance is 50% is λ _AT 50 _% (nm) I assume. FIG. 4 shows the spectral transmittance curve of the infrared cut filter 10 when λ _{AT 50 %} = λ _{RT 50%} −20 nm, ie, λ _{AT 50%} is 20 nm shorter than λ _{RT 50%} .

Assuming that the wavelength at which the transmittance is 50% at an incident angle of 0 ° of the infrared cut filter 10 according to the present embodiment is λ _T 50 _% (nm), as shown in FIG. 4, in the infrared cut filter 10 according to the present embodiment. is a _T50% = about 646 nm lambda when the incident angle is 0 °, λ _T50% when the incident angle is 25 ° = about 645 nm, incident angle when the 35 ° λ _T50% = about 633nm It is. As described above, even if the incident angle changes from 0 ° to 35 °, the infrared cut filter 10 according to the present embodiment has λ _{T 50%} shifted to the short wavelength side by only about 13 nm, and the incident angle λ _{T 50%} The dependence is smaller than the incident angle dependence of λ _{RT 50%} of the first comparative example described above. Referring to FIG. 4, in the region where the transmittance is higher than 50%, there is almost no difference in the spectral transmittance curve even when the incident angle changes. On the other hand, in the region where the transmittance is lower than 50%, a difference appears in the spectral transmittance curve when the incident angle changes. However, the difference in the spectral transmittance curve in the region where the transmittance is lower than 50% is color reproducibility. There is no particular problem because the impact is small.

  Further, as shown in FIG. 4, the infrared cut filter 10 according to the present embodiment has a transient region in the vicinity of a wavelength of 600 nm to 700 nm, the transmittance changes sharply in this region, and good sharp cut characteristics Can be realized.

  The optical characteristics of the infrared cut filter 10 according to the present embodiment are determined by the combination of the infrared reflection layer 14 and the infrared absorption layer 16. Hereinafter, preferable optical characteristics of each of the infrared reflection layer 14 and the infrared absorption layer 16 will be described.

First, preferable optical characteristics of the infrared reflective layer 14 will be described. The infrared reflective layer 14 is designed to transmit visible light of at least a wavelength of 400 nm to 600 nm and to reflect infrared light of at least a wavelength of 750 nm, for the required performance. In the transition area between the transmission area and the reflection area, the wavelength at which the spectral transmittance is 50 _% is defined as the cutoff wavelength λ _{RT 50%} . Although depending on the spectral sensitivity region of the imaging device or the like, λ _{RT 50%} of the infrared reflection layer 14 is around the cutoff wavelength λ _{AT 50%} of the infrared absorption layer 16, preferably λ _{AT 50%} <λ _{RT 50%} . It is preferable to set as follows.

  In addition, the infrared reflection layer 14 is designed so that the transmittance in the visible region is as high as possible. This is to allow light in the visible region necessary for constructing an image to reach the light receiving surface of the imaging device as much as possible. On the other hand, the infrared reflective layer 14 is designed so that the transmittance in the infrared region is as low as possible. This is to block as much as possible rays of light that do not contribute to the image configuration or are harmful. The infrared reflective layer 14 has, for example, an average spectral transmittance of at least 90% in the visible region of at least a wavelength of 400 nm to 600 nm, and a spectral transmittance of less than 2% in an infrared region of at least wavelength 750 nm. preferable.

Furthermore, in the infrared reflection layer 14, it is preferable that the spectral transmittance changes sharply in a transition region (referred to as "sharp cut characteristics"). If the sharp cut characteristics are lost and the transition area becomes too large, it becomes difficult to control the color reproducibility. The steepness of the transmittance in the transition region _{λ RSLOPE = | λ RT50% -λ} RT2% | ( wavelength lambda _RT2% is the spectral transmittance is 2%) and when defined, lambda _RSLOPE infrared reflective layer 14 as much as possible It is preferably small, for example λ _RSLOPE is preferably less than 70 nm.

In the spectral transmittance curve shown in FIG. 2, the average spectral transmittance in the visible region is 90% or more in any of the incident angles of 0 °, 25 °, and 35 °, and the average spectral transmittance in the infrared region is 2 It is less than%. Furthermore, in the spectral transmittance curve shown in FIG. 2, λ _RSLOPE is less than 70 nm in any of the incident angles of 0 °, 25 °, and 35 °. Accordingly, the infrared absorbing layer 16 having the spectral transmittance curve shown in FIG. 2 can be suitably applied to the infrared cut filter 10 according to the present embodiment.

  Next, preferable optical properties of the infrared absorbing layer 16 will be described. In the present embodiment, the optical characteristics required of the infrared absorption layer 16 change according to the optical characteristics of the infrared reflection layer 14 to be combined.

In the present embodiment, it cut-off wavelength lambda _AT50% of the infrared absorbing layer 16 is less than the cutoff wavelength lambda _RT50% of the infrared reflective layer 14, i.e., is preferably λ _AT50% <λ _RT50% . When the infrared absorbing layer 16 satisfies this condition, the incident angle dependency of the infrared blocking property of the infrared cut filter 10, in other words, the cut-off wavelength of the infrared cut filter 10 when the incident angle changes from 0 ° to 35 ° The shift amount of λ _{T 50%} can be reduced.

  Furthermore, in the present embodiment, it is preferable that the average transmittance in the visible region of the infrared absorbing layer 16 be as high as possible. When the average transmittance of the infrared absorbing layer 16 is low, the amount of light reaching the imaging device is reduced. For example, it is preferable that the average transmittance | permeability in wavelength 400nm-600nm of the infrared rays absorption layer 16 is 80% or more.

In the present embodiment, the spectral transmittance of the infrared absorbing layer 16 is irrelevant in the region of wavelengths longer than λ _{RT 2%} . In this region, since the spectral transmittance of the infrared reflective layer 14 is very small, the transmittance of the infrared cut filter 10 as a whole can be lowered.

Further, in the present embodiment, it is preferable that the spectral transmittance curve of the infrared absorption layer 16 monotonously decreases in the transient region (for example, 600 nm to λ _RT2% ). It is easy to obtain an indication of the cutoff wavelength λ _{T 50%} of the infrared cut filter 10 by combining it with the infrared reflective layer 14, and it is advantageous in that the setting can be performed easily and freely and the control of color reproducibility is easy. Because

Hereinafter, while showing the Example of the infrared cut filter using the infrared reflective film and infrared absorbing layer which satisfy | fill all the above-mentioned suitable conditions as 1st-3rd Example, cut-off wavelength (lambda) _{RT50% of the} infrared reflective layer 14 And a detailed study of the relationship between the infrared absorption layer 16 and the cutoff wavelength λ _{AT 50%} .

  FIG. 5 shows the composition of the infrared absorbing layer used in the first to third examples. The infrared absorbing layer used in the first example was formed by the following procedure. First, using MEK (methyl ethyl ketone) as a solvent, 0.002 / 0.807 = 0.25 wt% of KAYASORB CY-10 (cyanine compound) manufactured by Nippon Kayaku Co., Ltd. 0.13 wt%, KAYASORB IRG-022 (diimonium compound) manufactured by Nippon Kayaku Co., Ltd. is added to 0.055 g of PVB (polyvinyl butyral) at 0.003 / 0.807 = 0.37 wt%. Stir for 10-15 minutes after blending. This solution is uniformly coated on one surface of a glass substrate by a flow coating method, and allowed to stand for 2 hours for sufficient drying. The said glass plate was heated at 140 degreeC for 20 minutes, and the infrared rays absorption layer was formed. The infrared absorbing layers used in the second and third examples were also formed in the same manner using the dyes shown in FIG. The spectral transmittance curves of the infrared absorbing film alone formed in this manner are shown in FIG. 21, FIG. 22, and FIG. The average transmittances at wavelengths of 400 nm to 600 nm in the first to third embodiments are 80.4%, 80.6%, and 80.7%, respectively. Furthermore, in the region of wavelengths longer than 600 nm, it tends to decrease monotonously. As shown in FIGS. 20 to 23, the spectral transmittance curve of the infrared absorbing film has a wavelength of 700 nm to 800 nm (first embodiment: see FIG. 20) at wavelengths of 600 nm or more, and in some cases, a wavelength of 700 nm to 750 nm (second And the third embodiment: see FIG. 22 and FIG.

The more preferable conditions of the cutoff wavelength λ _{RT 50% of the} infrared reflection layer 14 and the cutoff wavelength λ _{AT 50%} of the infrared absorption layer 16 will be described. 6 (a) to 6 (m) show the spectral transmittance curves of the infrared cut filter when the difference between _{λAT 50%} and λ _{RT 50%} in the first embodiment is changed by 10 nm. FIGS. 7A to _7M show spectral transmittance curves of the infrared cut filter when the difference between _{λAT 50%} and λ _{RT 50%} in the second embodiment is changed by 10 nm. 8 (a) to 8 (m) show the spectral transmittance curves of the infrared cut filter when the difference between _{λAT 50%} and λ _{RT 50%} in the third embodiment is changed by 10 nm. 6 (a) to 6 (m), 7 (a) to 7 (m), and 8 (a) to 8 (m), a solid line indicates a spectral transmittance curve when the incident angle is 0 °, and a broken line indicates a curve. A spectral transmittance curve at an incident angle of 25 ° is shown, and a dashed-dotted line indicates a spectral transmittance curve at an incident angle of 35 °. In any of the embodiments, as shown in FIG. 20, λ _{AT 50%} of the infrared absorption layer 16 is fixed, and the cutoff wavelength λ _{RT 50%} of the infrared reflection layer 14 is changed to obtain λ _{AT 50%} and λ The difference between _{RT 50%} was set. Since the infrared reflective layer 14 is formed of a dielectric multilayer film, it is possible to easily realize a change in the transient region by adjusting the film thickness and the number of layers. Although FIG. 20 shows the change of the spectral transmittance curve of the infrared reflective layer according to the first embodiment, the spectral transmittance curve of the infrared reflective layer according to the second embodiment and the third embodiment changes similarly. It can be done.

FIG. 6 (a), the FIG. 7 (a), the 8 (a) is, 60 nm longer than the first to 3 lambda in Example _{AT50% -λ RT50%} = 60nm, i.e. lambda _AT50% is lambda _RT50% respectively The spectral transmission factor curve of the infrared cut filter in the case is shown. 6 (b), 7 (b) and 8 (b) show that λ _AT 50 _% −λ _{RT 50%} = 50 nm in the first to third embodiments, ie, λ _{AT 50%} is 50 nm longer than λ _{RT 50%.} The spectral transmission factor curve of the infrared cut filter in the case is shown. 6 (c), 7 (c) and 8 (c), respectively, _{show that? AT 50%} -? _{RT 50%} = 40 nm in the first to third embodiments, that is _{,? AT 50%} is 40 nm longer than? _{RT 50%.} The spectral transmission factor curve of the infrared cut filter in the case is shown. FIG. 6 (d), the FIG. 7 (d), the FIG. 8 (d) is, 30 nm longer than the first to 3 lambda in Example _{AT50% -λ RT50%} = 30nm, i.e. lambda _AT50% is lambda _RT50% respectively The spectral transmission factor curve of the infrared cut filter in the case is shown. FIG. 6 (e), the FIG. 7 (e), the Figure 8 (e) is, 20 nm longer than the first to 3 lambda in Example _{AT50% -λ RT50%} = 20nm, i.e. lambda _AT50% is lambda _RT50% respectively The spectral transmission factor curve of the infrared cut filter in the case is shown. 6 (f), 7 (f) and 8 (f) show λ _{AT 50%} −λ _{RT 50%} = 10 nm in the first to third embodiments, ie, λ _{AT 50%} is 10 nm longer than λ _{RT 50%.} The spectral transmission factor curve of the infrared cut filter in the case is shown. FIG 6 (g), FIG. 7 (g), FIG. 8 (g) are, lambda in the first to third embodiments, respectively _{AT50% -λ RT50%} = 0nm, i.e. lambda _AT50% and lambda _RT50% is equal The spectral transmission factor curve of an infrared cut filter is shown. FIG. 6 (h), the FIG. 7 (h), Fig. 8 (h) is, lambda _AT50% in the first to third embodiments, respectively -λ _RT50% = -10nm, i.e. 10nm than lambda _AT50% is lambda _RT50% The spectral transmission factor curve of the infrared cut filter in the case of short is shown. FIG 6 (i), Fig. 7 (i), FIG. 8 (i) is, lambda _AT50% in the first to third embodiments, respectively -λ _RT50% = -20nm, i.e. 20nm than lambda _AT50% is lambda _RT50% The spectral transmission factor curve of the infrared cut filter in the case of short is shown. FIG 6 (j), Fig. 7 (j), Fig. 8 (j) is, lambda _AT50% in the first to third embodiments, respectively -λ _RT50% = -30nm, i.e. 30nm than lambda _AT50% is lambda _RT50% The spectral transmission factor curve of the infrared cut filter in the case of short is shown. FIGS. 6 (k), 7 (k) and 8 (k) show that λ _{AT 50%} −λ _{RT 50%} = _{−40 nm} in the first to third embodiments, ie, λ _{AT 50%} is 40 nm more than λ _{RT 50%.} The spectral transmission factor curve of the infrared cut filter in the case of short is shown. FIG 6 (l), FIG. 7 (l), FIG. 8 (l) is, lambda _AT50% in the first to third embodiments, respectively -λ _RT50% = -50nm, i.e. 50nm than lambda _AT50% is lambda _RT50% The spectral transmission factor curve of the infrared cut filter in the case of short is shown. FIGS. 6 (m), 7 (m) and 8 (m) show λ _{AT 50%} −λ _{RT 50%} = −60 nm in the first to third embodiments, ie, λ _{AT 50%} is 60 nm more than λ _{RT 50%.} The spectral transmission factor curve of the infrared cut filter in the case of short is shown. Further, the spectral transmittance curves (first embodiment) of FIGS. 6 (a) to 6 (m), the spectral transmittance curves (second embodiment) shown in FIGS. 7 (a) to 7 (m), and FIG. 8 (a) The main parameters of the spectral transmittance curve (third embodiment) shown in (m) are shown in FIG. 9, FIG. 10, and FIG. 11, respectively.

In evaluating the spectral transmittance curves shown in FIGS. 6 (a) to 6 (m), 7 (a) to 7 (m), and 8 (a) to 8 (m), the inventor uses an infrared cut filter. The following (1) and (2) were set as the fundamentally required characteristics (hereinafter referred to as "basic characteristics").
(1) Average transmittance T _ave > 70% at a wavelength of 400 nm to 600 nm
(2) λ _SLOPE = | λ _{T 50%} -λ _{T 2%} | <70 nm (sharp cut characteristics)

Regarding the basic characteristics of the average transmittance T _ave shown in the above (1), the spectral transmittance curve in the case of λ _{AT 50%} −λ _{RT 50%} = 60 nm shown in FIG. 8A does not satisfy this required characteristic, The spectral transmittance curves shown in FIGS. 6 (a) to 6 (m), 7 (a) to 7 (m), and 8 (b) to 8 (m) satisfy this basic characteristic.

FIG. 12 (a), the FIG. 13 (a), the FIG. 14 (a), cut-off wavelength of the cut-off wavelength lambda _AT50% and the infrared reflective layer 14 of the infrared absorbing layer 16 in the first to third embodiments, respectively lambda _{RT50 %} difference and λ _AT50% -λ _RT50%, steepness lambda _SLOPE = the transition region of the spectral transmittance curve of | showing a relationship between | lambda _T50% 1-? _T2%. As described above, in the infrared cut filter, the steepness (sharp cut characteristic) of the transient region of the spectral transmittance curve is preferably as small as possible, and desirably less than 70 nm from the above basic characteristic (2). Therefore, according to FIGS. 12 (a), 13 (a) and 14 (a), it is desirable that −50 ≦ λ _{AT 50%} −λ _{RT 50%} .

Furthermore, the inventor set the following (3) as a characteristic for improving the incident angle dependency of the infrared ray blocking characteristic, which is the main subject of the present invention. Assuming that the shift amount of the cutoff wavelength λ _{T 50%} when the incident angle changes from 0 ° to 35 ° is Δλ _{T 50%} ,
(3) Δλ _T50% <25 nm

FIG. 12 (b), the FIG. 13 (b), the FIG. 14 (b), the cut-off wavelength of the cut-off wavelength lambda _AT50% and the infrared reflective layer 14 of the infrared absorbing layer 16 in the first to third embodiments, respectively lambda _{RT50 The relationship} between the _% difference λ _{AT 50 %} −λ _{RT 50%} and the shift amount Δλ _{T 50%} of the cutoff wavelength λ _{T 50%} when the incident angle changes from 0 ° to 35 ° is shown. From the above requirement characteristic (3), it is desirable that Δλ _{T 50%} be less than 25 nm. Therefore, as shown in FIG. 12 (b), FIG. 13 (b) and FIG. 14 (b), it is desirable that λ _{AT 50%} −λ _{RT 50%} ≦ −10 nm.

From the above consideration, it is desirable that the difference between the cutoff wavelength λ _{AT 50%} of the infrared absorption layer 16 and the cutoff wavelength λ _{RT 50%} of the infrared reflection layer 14 satisfy the following conditions.
−50 nm ≦ λ _{AT 50%} −λ _{RT 50%} ≦ −10 nm
By satisfying all the above-described required characteristics, it is possible to obtain a good image in which image quality factors such as transmittance and color quality are well balanced. Note that the above-described requirement characteristics are an example, and it is also possible to change the requirement specifications so as to match, for example, the characteristics of the imaging device.

The cutoff wavelength λ _T50% when the incident angle of light to the infrared cut filter is 35 ° is calculated as λ _T50% -Δλ _T50% . Cutoff wavelength λ at an incident angle of 35 ° when the above condition (−50 nm ≦ λ _{AT 50%} −λ _{RT 50%} ≦ −10 nm) is satisfied based on the parameters of the first to third embodiments shown in FIGS. 9 to 11 calculating the _{T50%, λ T50%} = the 607nm~647nm (λ _AT50% in the third embodiment shown in FIG. 11 -λ _RT50% = time of -60nm, 630nm-23nm = 607nm, first shown in FIG. 9 when λ _AT50% -λ _RT50% = -50nm example, 649-2 = 647nm). Therefore, in order to obtain a good image, it is desirable that the cutoff wavelength λ _T50% be 607 nm to 647 nm when the incident angle of light to the infrared cut filter is 35 °.

  The infrared cut filter 10 according to the present embodiment has been described above. According to the infrared cut filter 10 of the present embodiment, the infrared reflection layer 14 is formed on one surface of the transparent dielectric substrate 12, and the infrared absorption layer 16 is formed on the other surface. It is possible to provide an infrared cut filter having less good infrared blocking properties.

  In the infrared cut filter 10 according to the present embodiment, a general glass substrate can be used as the transparent dielectric substrate 12. Since it is not necessary to use a glass which is fragile and difficult to process such as fluoric acid glass, it is possible to perform general processes such as polishing and cutting, and as a result, it is easy to change the thickness such as thinning.

  In the infrared cut filter 10 according to the present embodiment, the combination of the optical characteristics of the infrared reflection layer 14 and the optical characteristics of the infrared absorption layer 16 determines the characteristics of the infrared cut filter 10 as a whole. The optical properties of the infrared reflective layer 14 can be easily changed by adjusting the layer structure of the dielectric multilayer film. Further, the optical properties of the infrared absorbing layer 16 can be easily changed by adjusting the type and concentration of the infrared absorbing dye contained in the resin matrix, and adjusting the thickness of the infrared absorbing layer. On the other hand, for example, when fluorophosphate glass is used to have an infrared absorption function, the modification of the infrared absorption characteristics can be achieved by melting the fluorophosphate glass using a furnace, cutting the fluorophosphate glass, and adjusting the fluorophosphate glass for thickness control. It is not easy because polishing is required. As described above, the infrared cut filter 10 according to the present embodiment is also excellent in that the optical characteristics of the infrared cut filter 10 can be easily changed.

  In the infrared cut filter 10 shown in FIG. 1, the infrared reflective layer 14 may be formed to reflect ultraviolet light. When the infrared cut filter 10 is formed of a dielectric multilayer film, the ultraviolet cut function can be easily incorporated into the infrared cut filter 10 by adjusting the layer configuration. The color filter provided in the imaging device may have an adverse effect such as a decrease in life due to ultraviolet light. Therefore, by removing the ultraviolet light in the infrared reflection layer 14 located in front of the imaging device, such an adverse effect can be avoided. Further, when the ultraviolet reflection function is incorporated in the infrared reflection layer 14, the ultraviolet light can be removed before reaching the infrared absorption layer 16 formed of the resin matrix, so that the deterioration of the infrared absorption layer 16 can be prevented.

  FIG. 15 shows an infrared cut filter 10 according to another embodiment of the present invention. In the infrared cut filter 10 shown in FIG. 15, components identical or corresponding to those of the infrared cut filter shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be appropriately omitted.

  The infrared cut filter 10 according to the present embodiment is different from the infrared cut filter shown in FIG. 1 in that a protective layer 18 is formed on the infrared absorption layer 16. As shown in FIG. 15, the protective layer 18 is formed on the surface of the infrared absorbing layer 16 opposite to the surface on the transparent dielectric substrate 12 side. In the infrared cut filter 10 according to the present embodiment, light is emitted from the protective layer 18.

  The infrared absorbing layer 16 is a layer containing an infrared absorbing dye, and thus contains an organic component. Therefore, the abrasion resistance and the humidity resistance are relatively weak. Therefore, the infrared absorption layer 16 can be protected by providing the protective layer 18 having a composition different from that of the infrared absorption layer 16 on the infrared absorption layer 16 as in the present embodiment.

The protective layer 18 may be, for example, a sol-gel hard coating mainly composed of TEOS (tetraethoxysilane). The protective layer 18 is, for example, (a) coating a hard coating agent on the infrared absorbing layer 16, (b) coating a sol-gel film on the infrared absorbing layer 16, (c) a SiO ₂ layer on the infrared absorbing layer 16 The dielectric film can be formed by vapor deposition, etc., but is not particularly limited thereto.

  In the infrared cut filter 10 shown in FIG. 15, the protective layer 18 may be formed to prevent reflection of visible light. By covering the infrared absorption layer 16 with a material having a refractive index lower than that of the infrared absorption layer 16, the protective layer 18 can have an antireflective function of visible light. As a result, the visible light transmittance of the infrared cut filter 10 as a whole can be improved. Alternatively, as the protective layer 18, an antireflection film made of a dielectric multilayer film may be formed on the infrared absorption layer 16.

  In the infrared cut filter 10 shown in FIG. 15, the protective layer 18 may be formed to prevent the transmission of ultraviolet light. In this case, it is possible to prevent the ultraviolet light incident from the light emission surface side from reaching the imaging element, so it is possible to prevent the deterioration of the color filter provided in the imaging element.

  FIG. 16 shows an infrared cut filter 10 according to yet another embodiment of the present invention. In the infrared cut filter 10 shown in FIG. 16, the same or corresponding components as or to those of the infrared cut filter shown in FIG. 1 and FIG.

  The infrared cut filter 10 according to the present embodiment differs from the infrared cut filter shown in FIG. 15 in that an antireflection layer 20 for preventing reflection of visible light is formed on the protective layer 18. As shown in FIG. 16, the antireflective layer 20 is formed on the surface of the protective layer 18 facing the surface on the side of the infrared absorption layer 16. In the infrared cut filter 10 according to the present embodiment, light is emitted from the antireflection layer 20.

  Even when the antireflection layer 20 is formed on the protective layer 18 as in the infrared cut filter 10 according to the present embodiment, the transmittance of visible light as the entire infrared cut filter 10 can be improved.

  In the infrared cut filter 10 shown in FIG. 16, the antireflective layer 20 may be formed to prevent transmission of ultraviolet light. In this case, it is possible to prevent the ultraviolet light incident from the light emission surface side from reaching the imaging element, so it is possible to prevent the deterioration of the color filter provided in the imaging element.

  FIG. 17 shows an infrared cut filter 10 according to yet another embodiment of the present invention. In the infrared cut filter 10 shown in FIG. 17, the same or corresponding components as or to those of the infrared cut filter shown in FIG.

  The infrared cut filter 10 according to this embodiment is different from the infrared cut filter shown in FIG. 1 in that a primer layer 22 is formed between the transparent dielectric substrate 12 and the infrared absorption layer 16. By forming the primer layer 22 between the transparent dielectric substrate 12 and the infrared absorption layer 16, the adhesion between the transparent dielectric substrate 12 and the infrared absorption layer 16 can be improved, and the environmental resistance of the infrared cut filter 10 is improved. it can.

  FIG. 18 shows an infrared cut filter 10 according to yet another embodiment of the present invention. In the infrared cut filter 10 shown in FIG. 18, the same or corresponding components as or to those of the infrared cut filter shown in FIG.

  The infrared cut filter 10 according to the present embodiment is different from the infrared cut filter shown in FIG. 1 in that the infrared reflective layer 14 is warped. The infrared reflective layer 14 is warped such that the surface facing the surface on the transparent dielectric substrate 12 is a convex surface. Further, in the present embodiment, as the infrared reflective layer 14 warps, the transparent dielectric substrate 12 and the infrared absorbing layer 16 also warp.

  As described above, when the infrared cut filter 10 is used in an imaging device, the infrared reflection layer 14 is mounted so as to face the imaging lens, and the infrared absorption layer 16 is mounted so as to face the imaging device. However, since the infrared cut filter 10 is very thin and small, it is not easy to distinguish between the infrared reflection layer 14 and the infrared absorption layer 16. Therefore, as in the present embodiment, it is possible to visually determine which surface is the infrared reflective layer 14 by bending the infrared reflective layer 14. By controlling the stress of the film surface when depositing the dielectric multilayer film on the transparent dielectric substrate 12, it is possible to adjust the degree of warpage of the infrared reflective layer 14 within a range that does not affect the optical characteristics.

  FIG. 19 is a view for explaining an imaging device 100 using the infrared cut filter 10 according to the embodiment of the present invention. As shown in FIG. 19, the imaging device 100 includes an imaging lens 102, an infrared cut filter 10, and an imaging element 104. The imaging device 104 may be a semiconductor solid-state imaging device such as a CCD or a CMOS. As shown in FIG. 19, the infrared cut filter 10 is provided between the imaging lens 102 and the imaging element 104 so that the infrared reflection layer 14 faces the imaging lens 102 and the infrared absorption layer 16 faces the imaging element 104. Be

  As shown in FIG. 19, light from a subject is condensed by the imaging lens 102, and after infrared light is removed by the infrared cut filter 10, the light enters the imaging element 104. As shown in FIG. 19, light is incident on the infrared cut filter 10 from the imaging lens 102 at various incident angles, but by using the infrared cut filter 10 according to the present embodiment, infrared light is preferably used regardless of the incident angle. Since it can be blocked, it is possible to capture a good image with high color reproducibility.

  In the above description, although the embodiment in which the infrared cut filter 10 is applied to an imaging device has been described, the infrared cut filter 10 according to the above embodiment can be applied to other applications. For example, the infrared cut filter 10 can be used as, for example, a heat ray shielding film such as a windshield glass or a side window of a car, or a glass for construction. The infrared cut filter 10 can also be used as a near infrared cut filter for a PDP (Plasma Display Panel).

  The present invention has been described above based on the embodiments. It will be understood by those skilled in the art that this embodiment is an exemplification, and that various modifications can be made to the combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. is there.

  10 infrared cut filter, 12 transparent dielectric substrate, 14 infrared reflective layer, 16 infrared absorbing layer, 18 protective layer, 20 antireflective layer, 22 primer layer, 100 imaging device, 102 imaging lens, 104 imaging element.

Claims (6)

A transparent dielectric substrate,
An infrared reflecting layer for reflecting infrared rays formed on one surface of the transparent dielectric substrate;
An infrared absorbing layer absorbing infrared rays formed on the other surface of the transparent dielectric substrate;
An infrared cut filter comprising
The infrared reflection layer is formed of a dielectric multilayer film.
The infrared absorbing layer is formed of a resin containing an infrared absorbing dye,
Assuming that the shift amount of the cutoff wavelength λ _{T 50%} when the incident angle of light to the infrared cut filter changes from 0 ° to 35 ° is Δλ _{T 50%} , Δλ _{T 50%} <25 nm,
A cutoff wavelength λ _{T 50%} when the incident angle of light to the infrared cut filter is 35 ° is 607 nm to 647 nm. _Assuming that the wavelength at which the transmittance of the infrared reflection layer is 50% is λ _{RT 50%} nm, and the wavelength at which the transmittance of the infrared absorption layer is 50% is λ _AT 50 _% nm, the light to the infrared cut filter the incident angle is 0 °, the infrared cut filter of claim 1, wherein the infrared reflective layer and the infrared-absorbing layer is formed so as to satisfy _{λ AT50% -λ RT50% ≦ -10nm} . Furthermore, the infrared reflection layer and the infrared absorption layer are formed such that an incident angle of light to an infrared cut filter satisfies ₋₅₀ nm ≦ λ _{AT 50%} −λ _{RT 50%} at 0 °. The infrared cut filter as described in 2.   The infrared cut filter according to any one of claims 1 to 3, wherein the spectral transmittance curve of the infrared absorbing layer has a minimum value of transmittance at a wavelength of 700 nm to 750 nm. The infrared cut filter according to any one of claims 1 to 4.
An imaging element on which light transmitted through the infrared cut filter is incident;
An imaging apparatus comprising: Preparing a transparent dielectric substrate;
Forming an infrared reflective layer on one side of the transparent dielectric substrate;
Forming an infrared absorbing layer on the other side of the transparent dielectric substrate;
A method of manufacturing an infrared cut filter comprising:
The infrared reflection layer is formed of a dielectric multilayer film.
The infrared absorbing layer is formed of a resin containing an infrared absorbing dye,
Assuming that the shift amount of the cutoff wavelength λ _{T 50%} when the incident angle of light to the infrared cut filter changes from 0 ° to 35 ° is Δλ _{T 50%} , Δλ _{T 50%} <25 nm,
The cutoff wavelength λ _{T 50%} when the incident angle of light to the infrared cut filter is 35 ° is 607 nm to 647 nm,
_Assuming that the wavelength at which the transmittance of the infrared reflection layer is 50% is λ _{RT 50%} nm, and the wavelength at which the transmittance of the infrared absorption layer is 50% is λ _AT 50 _% nm, the light to the infrared cut filter The method for manufacturing an infrared cut filter, wherein the infrared reflection layer and the infrared absorption layer are formed to satisfy λAT50 _% −λRT50 _% ≦ −10 _nm at an incident angle of 0 °.

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