TW201939073A - Optical filter and imaging device - Google Patents

Abstract

An optical filter (1a) is provided with a light absorbing layer (10). When light having a wavelength of 300-1200 nm is made incident on the optical filter at the incident angles of 0 DEG, 30 DEG, and 40 DEG, (i-1) the spectral transmittance at a wavelength of 390 nm, (ii-1) the spectral transmittance at a wavelength of 400 nm, (iii-1) the spectral transmittance at a wavelength of 450 nm, (iv-1) the spectral transmittance at a wavelength of 700 nm, (v-1) the spectral transmittance at a wavelength of 715 nm, (vi-1) the spectral transmittance at a wavelength of 1100 nm, (vii-1) the spectral transmittance at a wavelength of 1200 nm, (viii-1) the average transmittance of a wavelength of 500-600 nm, and (ix-1) the average transmittance of a wavelength of 700-800 nm, satisfy a prescribed condition.

Description

Filter and camera

The invention relates to an optical filter and an imaging device.

Conventionally, an imaging device including a filter such as a near-infrared cut filter is known. For example, Patent Document 1 describes a near-infrared cut filter including a laminated plate having a resin layer containing a near-infrared absorber on at least one side of a glass plate substrate. For example, the near-infrared cut filter has a dielectric multilayer film on at least one side of the laminated board. In this near-infrared cut-off filter, the absolute value | Ya-Yb | of the difference between the wavelength value (Ya) and the wavelength value (Yb) is less than 15 nm. The value of the wavelength (Ya) is the value of the wavelength at which the transmittance becomes 50% when measured from the vertical direction of the near-infrared cut filter in the range of 560 to 800 nm. The value of the wavelength (Yb) is a value of a wavelength of 50% when the vertical direction of the near-infrared cut filter is measured from an angle of 30 ° in the range of 560 to 800 nm. As described above, according to Patent Document 1, the angle dependency of the penetration characteristics in the near-infrared cut filter is adjusted to be small.

Patent Literature 2 describes a near-infrared cut filter including a near-infrared absorbing glass substrate, a near-infrared absorbing layer, and a dielectric multilayer film. The near-infrared absorbing layer contains a near-infrared absorbing pigment and a transparent resin. Patent Document 2 describes a solid-state imaging device including the near-infrared cut filter and a solid-state imaging element. According to Patent Document 2, by laminating a near-infrared absorbing glass substrate and a near-infrared absorbing layer, the effect of the angular dependence of the shielding wavelength originally shifted by the dielectric multilayer film due to the incident angle of light can be roughly eliminated. For example, in Patent Document 2, the transmittance (T ₀ ) at an incident angle of 0 ° and the transmittance (T ₃₀ ) at an incident angle of 30 in the near-infrared cut filter are measured.

Patent Documents 3 and 4 describe an infrared cut filter including a dielectric substrate, an infrared reflective layer, and an infrared absorbing layer. The infrared reflecting layer is formed of a dielectric multilayer film. The infrared absorbing layer contains an infrared absorbing pigment. Patent Documents 3 and 4 describe an imaging device including the infrared cut filter. Patent Literatures 3 and 4 describe a transmittance spectrum of an infrared cut filter when the incident angles of light are 0 °, 25 °, and 35 °.

Patent Document 5 describes a near-infrared cut filter that includes an absorption layer and a reflection layer and satisfies specific requirements. For example, in this near-infrared cut-off filter, the integral value T _{0 ( 600-725 )} of the transmittance of light with a wavelength of 600 to 725 nm in the spectral transmittance curve at an incident angle of 0 ° and an incident angle of 30 ° The difference between the integral value T _{30 ( 600-725 )} of the transmittance of light with a wavelength of 600 to 725 nm in the spectral transmittance curve | T _{0 ( 600-725 )} -T _{30 ( 600-725 )} | 3%・ Nm or less. Patent Document 5 also describes an imaging device including the near-infrared cut filter.
[Prior technical literature]
[Patent Literature]

Patent Document 1: Japanese Patent Application Publication No. 2012-103340 Patent Document 2: International Publication No. 2014/030628 Patent Document 3: US Patent Application Publication No. 2014/0300956 Specification Patent Document 4: US Patent Application Publication No. 2014 / 0063597 Specification Patent Document 5: Japanese Patent No. 6119920

[Problems to be Solved by the Invention]

In the aforementioned patent documents, the characteristics of the filter when the incident angle of light is larger than 35 ° (for example, 40 °) are not specifically studied. Therefore, the present invention provides an optical filter having the characteristics that it is advantageous for use in an imaging device even when the incident angle of light is larger. The present invention also provides an imaging device including the filter.
[Technical means to solve the problem]

The present invention provides an optical filter,
It includes a light absorbing layer containing a light absorbing agent that absorbs at least a part of light in the near-infrared region,
When light having a wavelength of 300 nm to 1200 nm is incident on the filter at incidence angles of 0 °, 30 °, and 40 °, the following conditions are satisfied.
(I-1) The spectral transmittance at a wavelength of 390 nm is 20% or less.
(Ii-1) The spectral transmittance at a wavelength of 400 nm is 45% or less.
(Iii-1) The spectral transmittance at a wavelength of 450 nm is more than 75%.
(Iv-1) The spectral transmittance at a wavelength of 700 nm is 3% or less.
(V-1) The spectral transmittance at a wavelength of 715 nm is 1% or less.
(Vi-1) The spectral transmittance at a wavelength of 1100 nm is 2% or less.
(Vii-1) The spectral transmittance at a wavelength of 1200 nm is 15% or less.
(Viii-1) The average transmittance at a wavelength of 500 to 600 nm is 80% or more.
(Ix-1) The average transmittance at a wavelength of 700 to 800 nm is 0.5% or less.

In addition, the present invention provides an imaging device including:
Lens system
An imaging element that receives light passing through the lens system;
A color filter, which is arranged in front of the imaging element, and has three color filters of R (red), G (green), and B (blue); and the above-mentioned filter, which is arranged before the above-mentioned color filter square.
[Effect of the invention]

The above-mentioned filter has characteristics that are advantageous for use in an imaging device even when the incident angle of light is larger. In addition, according to the imaging device described above, even when the incident angle of light is larger, it is easy to generate a good-quality image.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description is an example of the present invention, and the present invention is not limited thereto.

The inventors of the present invention have developed the optical filter of the present invention based on new insights obtained through the following research related to the optical filter.

A camera module or an imaging device mounted on a mobile information terminal such as a smart phone is provided with a filter that blocks useless light other than visible light. The present inventors have studied the use of a filter provided with a light absorbing layer in order to shield useless light. Like the filters described in Patent Documents 1 to 5, a filter provided with a light absorbing layer often includes a reflective film made of a dielectric multilayer film.

In a reflective film composed of a dielectric multilayer film, the waveband of the transmitted light and the waveband of the reflected light are determined due to the interference of the light reflected from the surface and back of each layer of the reflective film. Light can enter the filter from various angles of incidence. The optical path length in the reflective film varies according to the incident angle of the light to the filter. As a result, the wavelength band of the transmitted light and the reflected light changes to the short wavelength side. Therefore, consider the way that the transmission characteristic of the filter does not change greatly due to the incident angle of light, and determine the boundary between the wavelength band of the light to be shielded and the wavelength band of the light to be penetrated by the absorption of light. The dielectric multilayer film keeps the wave band of the light that should be reflected away from the wave band of the light that should be penetrated.

In Patent Documents 1 and 2, the transmission characteristics of light in the near-infrared cut filter when the incident angle of light is 0 ° and 30 ° are evaluated. Further, in Patent Documents 3 and 4, the transmittance spectrum of the infrared cut filter when the incident angle of light is 0 °, 25 °, and 35 ° was evaluated. In recent years, camera modules mounted on mobile information terminals such as smart phones have required a wider viewing angle and a further reduction in height. Therefore, it is ideal to use the filter, even when the incident angle of light is larger (for example, 40 °), the waveband and light amount of the transmitted light are not easy to change.

In a filter provided with a reflective film composed of a dielectric multilayer film, if the incident angle of light is large, the reflectance of light locally increases in the wavelength band of light that originally wanted to suppress reflection and achieve high transmittance. Case. As a result, a defect called a ripple is locally generated in the filter. For example, even if the filter is designed in such a manner that moire does not occur when the incident angle of light is 0 ° to 30 °, if the incident angle of light increases to 40 °, moire is easily generated.

At present, there is no index to comprehensively evaluate the influence of the boundary between the band of transmitted light and the band of shielded light shifted by the change in the incident angle of light, and the effect of ripples. According to the technology described in Patent Document 5, the boundary between the band of visible light to be penetrated and the band of near-infrared to be reflected or absorbed is stable relative to the change in the incident angle of light. However, the technology described in Patent Document 5 has room for improvement in terms of the offset caused by a change in the incident angle at the boundary between the visible light band and the ultraviolet band, and the generation of ripples.

An RGB color filter is assembled on each pixel of the image sensor provided in the camera device. The amount of light perceived by each pixel of the sensor is the spectral transmittance and color filter of the filter that shields unnecessary light. The product of the divided light transmittances is related. Therefore, it is desirable that the filter has characteristics that are compatible with the characteristics of the color filter used in the imaging device.

Considering this situation, a filter having the following characteristics is studied day and night repeatedly: Even when the incident angle of light is larger, it is possible to appropriately shield useless light without damaging the brightness, which is advantageous for use in imaging devices. In addition, the filter with the following characteristics is also studied day and night. Even when the incident angle of light is larger, the transmission characteristics of the light in the filter are suppressed from being different. The image generated by the imaging device is advantageous for color unevenness. As a result, the inventors have developed the optical filter of the present invention.

In this specification, "spectral transmittance" refers to the transmittance when incident light of a specific wavelength is incident on an object such as a sample, and "average transmittance" refers to the average value of the spectral transmittance in a specific wavelength range. . In addition, in this specification, a "transmittance spectrum" is obtained by arranging the spectral transmittance of each wavelength in a specific wavelength range in the order of wavelength.

In this specification, "IR cut-off wavelength" means that when light with a wavelength of 300 nm to 1200 nm is incident on a filter at a specific incident angle, it exhibits a 50% spectral transmission in a wavelength range of 600 nm or more. Rate of wavelength. "UV cutoff wavelength" means a wavelength that exhibits a 50% spectral transmittance in a wavelength range below 450 nm when light with a wavelength of 300 nm to 1200 nm is incident on the filter at a specific incident angle.

As shown in FIG. 1A, the filter 1 a includes a light absorbing layer 10. The light absorption layer 10 contains a light absorber, and the light absorber absorbs at least a part of light in the near-infrared region. The filter 1a satisfies the following conditions when the light having a wavelength of 300 nm to 1200 nm is incident on the filter 1a at incidence angles of 0 °, 30 °, and 40 °.
(I-1) The spectral transmittance at a wavelength of 390 nm is 20% or less.
(Ii-1) The spectral transmittance at a wavelength of 400 nm is 45% or less.
(Iii-1) The spectral transmittance at a wavelength of 450 nm is more than 75%.
(Iv-1) The spectral transmittance at a wavelength of 700 nm is 3% or less.
(V-1) The spectral transmittance at a wavelength of 715 nm is 1% or less.
(Vi-1) The spectral transmittance at a wavelength of 1100 nm is 2% or less.
(Vii-1) The spectral transmittance at a wavelength of 1200 nm is 15% or less.
(Viii-1) The average transmittance at a wavelength of 500 to 600 nm is 80% or more.
(Ix-1) The average transmittance at a wavelength of 700 to 800 nm is 0.5% or less.

Since the filter 1a satisfies the conditions (i-1) to (ix-1) described above, even if the incident angle of light changes from 0 ° (perpendicular to the filter 1a) to 40 °, the filter can be suppressed. Changes in the penetration characteristics of 1a. Therefore, even if it is assembled in a camera module or an imaging device equipped with a wide-angle lens, it is possible to suppress the occurrence of different hue or brightness in the central portion of the image and the peripheral portion of the image, and shield unnecessary light.

When the filter 1a makes light having a wavelength of 300 nm to 1200 nm incident on the filter 1a at incidence angles of 0 °, 30 °, and 40 °, it is preferable to further satisfy the following conditions.
(I-2) The spectral transmittance at a wavelength of 390 nm is 10% or less.
(Ii-2) The spectral transmittance at a wavelength of 400 nm is 25% or less.
(Iv-2) The spectral transmittance at a wavelength of 700 nm is 2.5% or less.
(Vi-2) The spectral transmittance at a wavelength of 1100 nm is 1% or less.
(Vii-2) The spectral transmittance at a wavelength of 1200 nm is 13% or less.
(Viii-2) The average transmittance at a wavelength of 500 to 600 nm is 85% or more.

If the filter 1a further satisfies the conditions (i-2), (ii-2), (iv-2), (vi-2), (vii-2), and (viii-2) described above, Changing the incident angle from 0 ° to 40 ° can also more effectively suppress the change in the transmission characteristics of the filter. In addition, since the transmittance is higher in a wavelength region (500 to 600 nm) corresponding to the center of the visible light region, it is easy to obtain a brighter image. Furthermore, it is possible to more effectively shield useless light (light having a wavelength of 390 nm or less and light having a wavelength of 1100 to 1200 nm) which is not included in human visual sensitivity. Since these properties are maintained within an angle of incidence of 0 ° to 40 °, it is easy to obtain an image with a higher degree of color reproducibility.

When the filter 1a makes light having a wavelength of 300 nm to 1200 nm incident on the filter 1a at incident angles of 0 °, 30 °, and 40 °, it is preferable to further satisfy the following condition (ii-3), and more It is desirable to further satisfy the following condition (ii-4). Since the filter 1a satisfies the condition (iii-1), the spectral transmittance at a wavelength of 450 nm is higher than 75%. Therefore, the condition that satisfies (iii-1) interacts with the condition that satisfies (ii-3), and more desirably, the condition (ii-4) interacts. In the region with a relatively short wavelength, a sharp breakthrough occurs from a lower transmission The change is a higher penetration of the transmission characteristics. This transmission characteristic is ideal as an optical filter.
(Ii-3) The spectral transmittance at a wavelength of 400 nm is 15% or less.
(Ii-4) The spectral transmittance at a wavelength of 400 nm is 10% or less.

When the filter 1a makes light having a wavelength of 300 nm to 1200 nm incident on the filter 1a at incident angles of 0 °, 30 °, and 40 °, it is preferable to have an IR cutoff in a wavelength range of 600 nm to 650 nm. wavelength. In this case, in the specific sensitivity curve of a person in a bright field of view, the wavelength corresponding to the specific sensitivity of 0.5 in the range of 600 nm to 650 nm and a wavelength of 0.5 when the maximum value of the specific sensitivity is set to 1 The IR cutoff wavelength is close. This case is preferable from the viewpoint of the consistency between the transmission characteristics of the filter 1a and the specific sensitivity curve. When the filter 1a makes light having a wavelength of 300 nm to 1200 nm incident on the filter 1a at incident angles of 0 °, 30 °, and 40 °, it is more desirable to have an IR cutoff in the range of 610 nm to 640 nm. wavelength.

When the filter 1a makes light having a wavelength of 300 nm to 1200 nm incident on the filter 1a at incident angles of 0 °, 30 °, and 40 °, it is preferable to have a UV cutoff in a wavelength range of 400 nm to 430 nm. wavelength. From the viewpoint of effectively shielding the ultraviolet rays that may affect the performance degradation of the imaging element or color filter, and the compensation of the sensitivity to the relatively low sensitivity blue light (including light with a wavelength of about 450 nm), In other words, there is a requirement that the UV cut-off wavelength exists in a wavelength range of 400 nm to 430 nm. Therefore, it is preferable that the UV cutoff wavelength in the filter 1a is in such a wavelength range. When the filter 1a makes light having a wavelength of 300 nm to 1200 nm incident on the filter 1a at incident angles of 0 °, 30 °, and 40 °, it is more desirable to have UV cutoff in a wavelength range of 405 nm to 430 nm. wavelength.

When the light having a wavelength of 300 nm to 1200 nm is incident on the filter 1a at incidence angles of 0 °, 30 °, and 40 °, the difference between the IR cutoff wavelength and the UV cutoff wavelength is preferably 200 nm or more. Thereby, the amount of light of the light belonging to the visible light region is increased, and the brightness of the obtained image is desirably increased.

The spectral transmittance of the filter 1a at the wavelength λ when the incident angle of light is θ ° is represented as T _θ (λ). The minimum and maximum values of the variable range of the wavelength λ are expressed as λ1 [nm] and λ2 [nm], respectively. The function of the wavelength λ with an integer n above 0 is expressed as λ (n) = (Other fonts are used in the ∆ file, please adjust the font (please set the Chinese character to the new detail style, and the English character to the Times New Roman) Λ × n + λ1) [nm]. ∆ There are other fonts used in the document, please adjust the font (Please set the Chinese characters to the new detail style, and the English characters to the Times New Roman). The value of λ is a normal number. In this manual, other fonts are used in the ∆ file. Please adjust the fonts (please set the Chinese characters to the new detail style and the English characters to the Times New Roman type). λ = 1. That is, λ (n) is determined at 1 nm intervals. There are other fonts used in the ∆ file. Please adjust the font (for Chinese characters, please set the new detail style, for English characters, please set it to Times New Roman). When λ is a normal number other than 1, the spectral transmittance T _θ (λ) based on λ (n) can be obtained by linear interpolation. In the filter 1a, it is preferable that IE _{θ1 / θ2} ^{λ1 to λ2} satisfy the conditions shown in the following Table (I). IE _{θ1 / θ2} ^{λ1 to λ2} are the variable domains of the wavelengths λ at λ1 = 350 and λ2 = 800 for two incident angles θ1 ° and θ2 ° (θ1 <θ2) selected from 0 °, 30 °, and 40 ° , The variable domains of the wavelength λ of λ1 = 380 and λ2 = 530, the variable domains of the wavelength λ1 of λ1 = 450 and λ2 = 650, and the variable domains of the wavelength λ of λ1 = 530 and λ2 = 750, from The formula (1) is defined.

[Table 1]

The incident angle of the main ray incident to the center of the imaging element of the imaging device is close to 0 °, and the incident angle of the main ray incident to the peripheral portion of the imaging element is large. When equipped with a filter such as the spectral sensitivity curve or transmittance spectrum that changes due to the incident angle of light, when displaying or printing an image generated by an imaging device, the color tone of the image Subject to change. Therefore, when displaying or printing an image captured by an imaging device, the color of a subject that should be the same color changes from the center portion to the peripheral portion, and it can be recognized as color unevenness. Corresponds to a change in the range of 30 ° to 40 ° of the incident angle of light compared to a change in the angle of incidence of light from 0 ° to 40 ° and a change in the incident angle of light of 0 ° to 30 ° The area of the image is narrower, and color unevenness is more easily recognized in this area. Therefore, even if the incident angle of light to the filter is changed, if the shape of the spectral transmittance curve of the filter is small, the image generated by the imaging device is unlikely to produce color unevenness. Since the filter 1a satisfies the conditions shown in Table (I), even if the incident angle of light changes, the shape of the spectral transmittance curve changes little. With the imaging device having such a filter 1a, it is possible to Effectively prevent color unevenness in the image generated by the imaging device. In addition, the variable domain of the wavelength λ of λ1 = 350 and λ2 = 800 corresponds to a wavelength range including the entire range of visible light. On the other hand, the variable domains of the wavelength λ of λ1 = 380 and λ2 = 530, the variable domains of the wavelength λ1 of λ1 = 450 and λ2 = 650, and the variable domains of the wavelength λ of λ1 = 530 and λ2 = 750 respectively. The wavelength range of light of the blue (BLue: B) color filter, the green (Green: G) color filter, and the red (Red: R) color filter mounted on the color image sensor corresponds. In the filter 1a, since the conditions shown in Table (I) are satisfied, the filter 1a can be evaluated as being easily adapted to the characteristics of the color filter used in the imaging device.

As shown in formula (1), IE _{θ1 / θ2} ^{λ1 to λ2} are integrated in the wavelength range of λ1 nm ^{to λ2} nm from the spectral transmittance T _θ1 (λ) integrated from the incident angle θ1 ° selected from 0 ° and 30 °. It is determined by subtracting the difference in the spectral transmittance T _θ2 (λ) of the incident angle θ2 ° (θ1 <θ2) selected from 30 ° and 40 °. Therefore, by referring to IE _{θ1 / θ2} ^{λ1 to λ2} , the spectral transmittance in the range of λ1 [nm] ≦ wavelength λ ≦ λ2 [nm] when the incident angle changes from θ1 ° to θ2 ° can be quantitatively evaluated. The shape of the curve changes.

In the filter 1a, it is preferable that IAE _{θ1 / θ2} ^{λ1 to λ2} satisfy the conditions shown in Table (II) below. IAE _{θ1 / θ2} ^{λ1 to λ2} are the variable domains of the wavelengths λ at λ1 = 350 and λ2 = 800 for two incident angles θ1 ° and θ2 ° (θ1 <θ2) selected from 0 °, 30 °, and 40 ° , The variable domains of the wavelength λ of λ1 = 380 and λ2 = 530, the variable domains of the wavelength λ1 of λ1 = 450 and λ2 = 650, and the variable domains of the wavelength λ of λ1 = 530 and λ2 = 750, as follows Formula (2) definition.

[Table 2]

As shown in equation (2), IAE _{θ1 / θ2} ^{λ1 to λ2} are integrated in the wavelength range of λ1 nm ^{to λ2} nm from the spectral transmittance T _θ1 (λ) of the incident angle θ1 ° selected from 0 ° and 30 °. It is determined by subtracting the absolute value of the difference between the spectral transmittance T _θ2 (λ) of the incident angle θ2 ° (θ1 <θ2) selected from 30 ° and 40 °. Only in the evaluation performed by IE _{θ1 / θ2} ^{λ1 to λ2} , it is possible to accumulate the difference in the wavelength range from λ1 nm ^{to λ2} nm from T _θ1 (λ) minus T _θ2 (λ) in the negative band The value is offset by the cumulative value in another band whose difference is positive, and it may be difficult to properly specify the characteristics of the filter. However, the filter 1a can be evaluated more appropriately by also referring to IAE _{θ1 / θ2} ^{λ1 to λ2} .

In the filter 1a, it is preferable that ISE _{θ1 / θ2} ^{λ1 to λ2} satisfy the conditions shown in the following Table (III). ISE _{θ1 / θ2} ^{λ1 ~ λ2} are the variable domains of the wavelengths λ at λ1 = 350 and λ2 = 800 for two incident angles θ1 ° and θ2 ° (θ1 <θ2) selected from 0 °, 30 ° and 40 ° , The variable domains of the wavelength λ of λ1 = 380 and λ2 = 530, the variable domains of the wavelength λ1 of λ1 = 450 and λ2 = 650, and the variable domains of the wavelength λ of λ1 = 530 and λ2 = 750, as follows Formula (3) is defined.

[table 3]

As shown in equation (3), ISE _{θ1 / θ2} ^{λ1 to λ2} are integrated in the wavelength range of λ1 nm ^{to λ2} nm from the spectral transmittance T _θ1 (λ) integrated from the incident angle θ1 ° selected from 0 ° and 30 °. It is determined by subtracting the square of the difference (transmittance difference) in the spectral transmittance T _θ2 (λ) of the incident angle θ2 ° (θ1 <θ2) selected from 30 ° and 40 °. As described above, in the evaluation performed by IE _{θ1 / θ2} ^{λ1 to λ2} , it may be difficult to properly specify the characteristics of the filter. In addition, in the evaluation performed by IAE _{θ1 / θ2} ^{λ1 to λ2} , it is not possible to properly evaluate the case where the transmittance difference between the incident angles changes slowly over a wide wavelength range and the ripple due to the narrow wavelength range. Different situations that produce rapid changes. However, the ISE _{θ1 / θ2} ^{λ1 ~ λ2} , which is determined by using the squared value of the integral transmittance difference as an index, can strengthen the sharp transmittance change and specifically exclude the latter pattern that has a greater impact on image quality. Therefore, the filter 1a can be evaluated more appropriately.

As long as the light absorber contained in the light absorption layer 10 absorbs at least a part of light in the near-infrared region, the filter 1a satisfies the conditions (i-1) to (ix-1) described above, and is not particularly limited. The light absorbing agent contained in the light absorbing layer 10 preferably satisfies (i-2), (ii-2), (iv-2), (vi-2), (vii-2) with the filter 1a. And (viii-2). The light absorbing agent contained in the light absorbing layer 10 is preferably determined so that the filter 1a satisfies the conditions shown in at least one of Table (I), Table (II), and Table (III). The light absorber is formed of, for example, phosphonic acid and copper ions. In this case, the light absorption layer 10 can absorb light in a wide range of wavelengths in the near-infrared region and the visible light region adjacent to the near-infrared region. Therefore, the filter 1a can exhibit desired characteristics even if it does not include a reflective film. Moreover, even when the filter 1a is provided with a reflective film, the filter 1a can be designed such that the wavelength band of the light reflected by the reflective film is sufficiently far from the wavelength band of the light to be transmitted. For example, the wavelength band of the light reflected by the reflective film can be set to a wavelength band of more than 100 nm from the wavelength band of the transition region where the transmittance sharply decreases as the wavelength increases. Thereby, even if the incident angle of the light is large, the wavelength band of the light reflected by the reflection film is shifted to the short wavelength side, and it also overlaps with the wavelength band of the light absorbed by the light absorption layer 10, and passes through the transition area of the filter 1a. The transmittance characteristics are not easily changed with the change of the incident angle of light. In addition, the light absorbing layer 10 can absorb light over a wide range of wavelengths in the ultraviolet region.

When the light absorbing layer 10 includes a light absorber formed of phosphonic acid and copper ions, the phosphonic acid includes, for example, a first phosphonic acid having an aryl group. In the first phosphonic acid, an aryl group is bonded to a phosphorus atom. Thereby, in the filter 1a, it is easy to satisfy the above-mentioned conditions.

The aryl group of the first phosphonic acid is, for example, a phenyl group, a benzyl group, a tolylmethyl group, a nitrophenyl group, a hydroxyphenyl group, a halogenated phenyl group in which at least one hydrogen atom of the phenyl group is substituted with a halogen atom, or A benzyl halide group in which at least one hydrogen atom on the benzene ring of a benzyl group is substituted with a halogen atom.

When the light absorbing layer 10 includes a light absorber formed of phosphonic acid and copper ions, the phosphonic acid preferably further includes a second phosphonic acid having an alkyl group. In the second phosphonic acid, the alkyl group is bonded to a phosphorus atom.

The alkyl group possessed by the second phosphonic acid is, for example, an alkyl group having 6 or less carbon atoms. The alkyl group may have any of a straight chain and a branched chain.

When the light absorbing layer 10 includes a light absorbing agent formed of phosphonic acid and copper ions, the light absorbing layer 10 preferably further includes a phosphate ester and a matrix resin in which the light absorbing agent is dispersed.

The phosphoric acid ester contained in the light absorbing layer 10 is not particularly limited as long as it can appropriately disperse the light absorbing agent. For example, the phosphoric acid ester represented by the following formula (c1) and the following formula (c2) are included. At least one of phosphate monoesters. In the following formula (c1) and (c2), R ₂₁ , R _22, and R ₃ are each a monovalent functional group represented by-(CH ₂ CH ₂ O) _n R ₄ , and n is 1 to 25. An integer, R ₄ represents an alkyl group having 6 to 25 carbon atoms. R ₂₁ , R ₂₂ and R ₃ are functional groups which are the same or different from each other.

The phosphate is not particularly limited, and may be, for example, Plysurf A208N: polyoxyethylene alkyl (C12, C13) ether phosphate, Plysurf A208F: polyoxyethylene alkyl (C8) ether phosphate, Plysurf A208B: polyoxyethylene lauryl ether Phosphate, Plysurf A219B: Polyoxyethylene lauryl ether phosphate, Plysurf AL: Polyoxyethylene styrenated phenyl ether phosphate, Plysurf A212C: Polyoxyethylene tridecyl ether phosphate, or Plysurf A215C: Polyoxyethylene ten Trialkyl ether phosphate. These are all products manufactured by First Industrial Pharmaceuticals. The phosphate ester may be NIKKOL DDP-2: polyoxyethylene alkyl ether phosphate, NIKKOL DDP-4: polyoxyethylene alkyl ether phosphate, or NIKKOL DDP-6: polyoxyethylene alkyl ether phosphate. These are manufactured by Nikko Chemicals.

The matrix resin contained in the light absorbing layer 10 is, for example, a resin capable of dispersing a light absorbing agent and being heat-curable or ultraviolet-curable. Furthermore, when the resin is used as a matrix resin to form a resin layer of 0.1 mm, the resin layer has a transmittance of, for example, 80% or more, and preferably 85%, for light having a wavelength of 350 nm to 900 nm. The above, more preferably 90% or more of the resin is not particularly limited as long as the conditions (i-1) to (ix-1) described above are satisfied in the filter 1a. The matrix resin preferably satisfies the conditions (i-2), (ii-2), (iv-2), (vi-2), (vii-2), and (viii-2) with the filter 1a. The way is ok. The matrix resin is preferably determined so that the filter 1a satisfies the conditions shown in at least one of Table (I), Table (II), and Table (III). The content of the phosphonic acid in the light absorbing layer 10 is, for example, 3 to 180 parts by mass based on 100 parts by mass of the matrix resin.

The matrix resin included in the light absorbing layer 10 is not particularly limited as long as it satisfies the above characteristics, and examples thereof include (poly) olefin resins, polyimide resins, polyvinyl butyral resins, polycarbonate resins, and polyfluorenes. Amine resin, polyfluorene resin, polyether resin, polyimide resin, (modified) acrylic resin, epoxy resin or silicone resin. The matrix resin may contain an aryl group such as a phenyl group, and is preferably a polysiloxane resin containing an aryl group such as a phenyl group. If the light absorbing layer 10 is hard (rigid), as the thickness of the light absorbing layer 10 increases, cracks are likely to occur due to hardening and shrinkage during the manufacturing process of the filter 1a. When the matrix resin is a silicone resin containing an aryl group, the light absorbing layer 10 easily has good crack resistance. In addition, when a polysiloxane resin containing an aryl group is used, the light absorber is less likely to aggregate when the light absorber formed from the phosphonic acid and copper ions described above is contained. Further, when the matrix resin of the light absorption layer 10 is a polysiloxane resin containing an aryl group, it is more preferable that the phosphoric acid ester contained in the light absorption layer 10 is a phosphoric acid represented by the formula (c1) or (c2). The ester has a flexible linear organic functional group such as an oxyalkyl group. The reason is that, based on the combination of the above-mentioned phosphonic acid, a polysiloxane resin containing an aryl group, and a phosphate ester having a linear organic functional group such as an oxyalkyl group, the light absorber is not easy to aggregate and can absorb light. The layer brings good rigidity and good softness. Specific examples of the silicone resin used as the matrix resin include KR-255, KR-300, KR-2621-1, KR-211, KR-311, KR-216, KR-212, and KR-251. . These are silicone resins manufactured by Shin-Etsu Chemical Industry Co., Ltd.

As shown in FIG. 1A, the filter 1 a further includes, for example, a transparent dielectric substrate 20. One of the main surfaces of the transparent dielectric substrate 20 is covered by the light absorbing layer 10. The characteristics of the transparent dielectric substrate 20 are not particularly limited as long as the conditions (i-1) to (ix-1) described above are satisfied in the filter 1a. The transparent dielectric substrate 20 preferably has, for example, the filter 1a and further satisfies (i-2), (ii-2), (iv-2), (vi-2), (vii-2), and (viii-2). ) Conditions. The transparent dielectric substrate 20 preferably has characteristics such that the filter 1a satisfies the conditions shown in at least one of Table (I), Table (II), and Table (III). The transparent dielectric substrate 20 is, for example, a dielectric substrate having a high average transmittance (for example, 80% or more, preferably 85% or more, and more preferably 90% or more) at 450 nm to 600 nm.

The transparent dielectric substrate 20 is made of glass or resin, for example. When the transparent dielectric substrate 20 is made of glass, the glass is, for example, borosilicate glass such as D263 T eco, soda lime glass (blue plate), white glass such as B270, alkali-free glass, or phosphate glass containing copper. Or infrared-absorbing glass such as copper-containing fluorophosphate glass. When the transparent dielectric substrate 20 is an infrared absorbing glass such as copper-containing phosphate glass or copper-containing fluorophosphate glass, the infrared absorption performance of the transparent dielectric substrate 20 and the light absorption layer 10 have The combination of infrared absorption performance can bring the required infrared absorption performance to the filter 1a. Such infrared-absorbing glass is, for example, BG-60, BG-61, BG-62, BG-63, or BG-67 manufactured by SCHOTT, 500EXL manufactured by Japan Electric Glass Co., Ltd., or CM5000, CM500 manufactured by HOYA Corporation. , C5000 or C500S. The transparent dielectric substrate 20 may have ultraviolet absorption characteristics.

The transparent dielectric substrate 20 may be a transparent crystalline substrate such as magnesium oxide, sapphire, or quartz. For example, sapphire is not easily damaged due to its high hardness. Therefore, the plate-shaped sapphire has a scratch-resistant protective material (also sometimes referred to as a protective filter or cover glass), which is arranged in front of the camera module or lens provided in mobile terminals such as smart phones and mobile phones. Situation. By forming the light absorbing layer 10 on such a plate-like sapphire, the camera module and the lens can be protected, and light with a wavelength of 650 nm to 1100 nm can be effectively cut off. It is not necessary to place a filter with infrared shielding wavelength of 650 nm to 1100 nm on the periphery of a camera element such as a CCD (Charge-Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor or a camera module Inside. Therefore, if the light absorbing layer 10 is formed on the plate-shaped sapphire, the height of the camera module or the imaging device can be reduced.

When the transparent dielectric substrate 20 is made of resin, the resin is, for example, a (poly) olefin resin, a polyimide resin, a polyvinyl butyral resin, a polycarbonate resin, a polyimide resin, or a polyimide resin. , Polyether 碸 resin, poly 、 amine （imine resin, (modified) acrylic resin, epoxy resin or polysiloxane resin.

The optical filter 1 a can be manufactured, for example, by applying a coating liquid for forming the light absorbing layer 10 on one of the main surfaces of the transparent dielectric substrate 20 to form a coating film, and drying the coating film. Taking the case where the light absorbing layer 10 contains a light absorbing agent formed of phosphonic acid and copper ions as an example, the preparation method of the coating liquid and the manufacturing method of the optical filter 1a are described.

First, an example of a method for preparing a coating liquid will be described. A copper salt such as copper acetate monohydrate is added to a specific solvent such as tetrahydrofuran (THF) and stirred to obtain a solution of the copper salt. Next, a phosphoric acid ester compound such as a phosphoric acid diester represented by the formula (c1) or a phosphoric acid monoester represented by the formula (c2) is added to the solution of the copper salt and stirred to prepare liquid A. The first phosphonic acid was added to a specific solvent such as THF and stirred to prepare a liquid B. Next, while stirring liquid A, add liquid B to liquid A and stir for a specific time. Next, a specific solvent such as toluene was added to the solution and stirred to obtain a liquid C. Next, while the C liquid was heated, the solvent was removed for a specific time to obtain a D liquid. Thereby, components generated by dissociation of a copper salt such as a solvent such as THF and acetic acid (boiling point: about 118 ° C.) are removed, and a light absorber is generated by the first phosphonic acid and copper ions. The temperature of the heating C liquid is determined based on the boiling points of the components to be removed from the dissociation of the copper salt. Furthermore, in the solvent removal treatment, solvents such as toluene (boiling point: about 110 ° C.) used to obtain liquid C are also volatilized. Since the solvent is preferably left to a certain extent in the coating liquid, from this viewpoint, it is preferable to determine the amount of the solvent to be added and the time for the desolvation treatment. Moreover, in order to obtain liquid C, o-xylene (boiling point: about 144 ° C) may be used instead of toluene. In this case, since the boiling point of o-xylene is higher than the boiling point of toluene, the amount of addition can be reduced to about one-fourth of the amount of toluene. A coating resin can be prepared by adding a matrix resin such as silicone resin to the D liquid and stirring it.

A coating liquid is applied to one main surface of the transparent dielectric substrate 20 to form a coating film. For example, a coating film is formed by applying a coating liquid to one main surface of the transparent dielectric substrate 20 by die coating, spin coating, or coating using a dispenser. Next, the coating film is subjected to a specific heat treatment to harden the coating film. For example, the coating film is exposed to a temperature of 50 ° C to 200 ° C for a specific time.

In the filter 1a, the light absorption layer 10 may be formed as a single layer or may be formed as a plurality of layers. When the light absorbing layer 10 is formed in multiple layers, the light absorbing layer 10 has, for example, a first layer containing a light absorbing agent formed of a first phosphonic acid and copper ions; and a second layer containing a second absorbing layer A light absorber formed by phosphonic acid and copper ions. In this case, the coating liquid used to form the first layer may be prepared as described above. On the other hand, the second layer is formed using a coating liquid prepared separately from the coating liquid used to form the first layer. The coating liquid for forming the second layer can be prepared, for example, as follows.

A copper salt such as copper acetate monohydrate is added to a specific solvent such as tetrahydrofuran (THF) and stirred to obtain a solution of the copper salt. Next, a phosphoric acid ester compound such as a phosphoric acid diester represented by the formula (c1) or a phosphoric acid monoester represented by the formula (c2) is added to the copper salt solution and stirred to prepare an E solution. The second phosphonic acid was added to a specific solvent such as THF and stirred to prepare a liquid F. Next, while stirring the E liquid, add the F liquid to the E liquid and stir for a specific time. Next, a specific solvent such as toluene is added to the solution and stirred, and the solvent is volatilized to obtain a G solution. Next, a matrix resin such as silicone resin is added to the G liquid and stirred to obtain a coating liquid for forming a second layer.

The coating liquid for forming the first layer and the coating liquid for forming the second layer are applied to form a coating film, and the coating film is subjected to a specific heat treatment to harden the coating film, thereby forming the first layer. And the second floor. For example, the coating film is exposed to a temperature of 50 ° C to 200 ° C for a specific time. The order of forming the first layer and the second layer is not particularly limited, and the first layer and the second layer may be formed at different times or may be formed at the same time. A protective layer may be formed between the first layer and the second layer. The protective layer is formed by, for example, a vapor-deposited film of SiO ₂ .

＜ Modifications ＞
The filter 1a can be changed according to various viewpoints. For example, the filter 1a may be changed to the filters 1b to 1f shown in FIGS. 1B to 1F, respectively. The filters 1b to 1f are configured in the same manner as the filter 1a except for the case where it is specifically described. The constituent elements of the filters 1b to 1f that are the same as or correspond to the constituent elements of the filter 1a are denoted by the same reference numerals, and detailed descriptions are omitted. The description related to the filter 1a is also applicable to the filters 1b to 1f as long as there is no technical contradiction.

As shown in FIG. 1B, in the optical filter 1 b, a light absorbing layer 10 is formed on two main surfaces of the transparent dielectric substrate 20. Accordingly, the conditions (i-1) to (ix-1) are satisfied by the two light absorption layers 10 instead of the one light absorption layer 10, and it is more desirable to further satisfy the above (i-2), The conditions of (ii-2), (iv-2), (vi-2), (vii-2), and (viii-2) are preferably to satisfy Tables (I), (II), and (III) The conditions shown in at least one of them. The thicknesses of the light absorbing layers 10 on the two main surfaces of the transparent dielectric substrate 20 may be the same or different. That is, the optical filter 1 b forms the light absorbing layers 10 on both main surfaces of the transparent dielectric substrate 20 in such a manner that the thickness of the light absorbing layer 10 required for obtaining the required optical characteristics is evenly or unevenly distributed. Thereby, the thickness of each light absorption layer 10 formed on one main surface of the transparent dielectric substrate 20 of the filter 1b is smaller than that of each light absorption layer 10 on one main surface of the transparent dielectric substrate 20 of the filter 1a. Of thickness. Since the light absorbing layers 10 are formed on both main surfaces of the transparent dielectric substrate 20, warpage is suppressed in the filter 1b even when the transparent dielectric substrate 20 is thin. Each of the two light-absorbing layers 10 may be formed in a plurality of layers.

As shown in FIG. 1C, in the optical filter 1 c, a light absorbing layer 10 is formed on both main surfaces of the transparent dielectric substrate 20. In addition, the filter 1 c includes an anti-reflection film 30. The antireflection film 30 is a film for reducing reflection of light in the visible light region, and is formed so as to form an interface between the filter 1c and air. The antireflection film 30 is, for example, a film made of a dielectric such as resin, oxide, and fluoride. The anti-reflection film 30 may be a multilayer film formed by laminating two or more dielectric materials having different refractive indexes. In particular, the anti-reflection film 30 may be a dielectric multilayer film composed of a low refractive index material such as SiO ₂ and a high refractive index material such as TiO ₂ or Ta ₂ O ₅ . In this case, the Fresnel reflection at the interface between the filter 1c and the air can be reduced, and the amount of light in the visible light region of the filter 1c can be increased. The anti-reflection film 30 may be formed on both sides of the filter 1c, or may be formed on one side of the filter 1c.

As shown in FIG. 1D, in the optical filter 1 d, a light absorbing layer 10 is formed on two main surfaces of the transparent dielectric substrate 20. In addition, the filter 1d further includes a reflective film 40. The reflection film 40 reflects infrared rays and / or ultraviolet rays. The reflection film 40 is, for example, a film formed by vapor deposition of a metal such as aluminum, or a dielectric multilayer film in which a layer made of a high refractive index material and a layer made of a low refractive index material are alternately laminated. As the high refractive index material, materials having a refractive index of 1.7 to 2.5, such as TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , ZnO, and In ₂ O ₃ , are used. As the low-refractive-index material, a material having a refractive index of 1.2 to 1.6, such as SiO ₂ , Al ₂ O _3, and MgF ₂ , is used. A method of forming the dielectric multilayer film is, for example, a chemical vapor deposition (CVD) method, a sputtering method, or a vacuum evaporation method. In addition, such a reflective film can be formed so as to form both main surfaces of an optical filter (not shown). If the reflective films are formed on the two main surfaces of the filter, the advantages of balanced stress on the surface and the back surface of the filter and the filter not easily warping are obtained.

As shown in FIG. 1E, the filter 1 e is composed of only the light absorption layer 10. The optical filter 1e can be manufactured, for example, by applying a coating liquid to a specific substrate such as a glass substrate, a resin substrate, or a metal substrate (such as a steel substrate or a stainless steel substrate) to form a coating film. The filter 1e can also be manufactured by a casting method. The filter 1e is thin because it does not include the transparent dielectric substrate 20. Therefore, the filter 1e can contribute to the height reduction of the imaging device.

As shown in FIG. 1F, the filter 1 f includes a light absorbing layer 10 and an antireflection film 30 disposed on one of both surfaces thereof. In this case, the filter 1f can contribute to the reduction in height of the imaging device, and can increase the amount of light in the visible light region compared to the filter 1e.

Each of the filters 1a to 1f can be changed to include an infrared absorbing layer (not shown) different from the light absorbing layer 10 as necessary. The infrared absorbing layer contains, for example, an organic infrared absorbent such as a cyanine-based, phthalocyanine-based, onium-based, diimmonium-based, or azo-based, or an infrared absorber composed of a metal complex. The infrared absorbing layer contains, for example, one or more infrared absorbing agents selected from the infrared absorbing agents. The wavelength range (absorption band) of light that this organic infrared absorber can absorb is small, and it is suitable for absorbing light in a specific range of wavelengths.

Each of the filters 1 a to 1 f can be changed to include an ultraviolet absorbing layer (not shown) different from the light absorbing layer 10 as necessary. The ultraviolet absorbing layer contains, for example, benzophenone-based, three-well-based, indole-based, merocyanine-based, and oroxazole-based ultraviolet absorbers. The ultraviolet absorbing layer contains, for example, one or more ultraviolet absorbing agents selected from the ultraviolet absorbing agents. These ultraviolet absorbers may include, for example, those that absorb ultraviolet rays in the vicinity of 300 nm to 340 nm, emit light (fluorescence) having a wavelength longer than the absorption wavelength, and perform functions as fluorescent agents or fluorescent whitening agents. The ultraviolet absorbing layer can reduce the incidence of ultraviolet rays that cause deterioration of materials used in filters such as resins.

The resin-made transparent dielectric substrate 20 may include the infrared absorber and / or ultraviolet absorber described above in advance to form a substrate having characteristics of absorbing infrared and / or ultraviolet rays. In this case, the resin must be able to dissolve or disperse the infrared absorber and / or ultraviolet absorber appropriately and be transparent. Examples of such resins include (poly) olefin resins, polyimide resins, polyvinyl butyral resins, polycarbonate resins, polyimide resins, polyimide resins, polyether resins, and polyimide resins.醯 Imine resin, (modified) acrylic resin, epoxy resin and silicone resin.

As shown in FIG. 2, the filter 1 a is used to manufacture an imaging device 100 (camera module), for example. The imaging device 100 includes a lens system 2, an imaging element 4, a color filter 3, and an optical filter 1a. The imaging element 4 receives light passing through the lens system 2. The color filter 3 is disposed in front of the imaging element 4 and has three color filters of R (red), G (green), and B (blue). The filter 1 a is disposed in front of the color filter 3. In particular, the light absorption layer 10 is formed in contact with the surface of the transparent dielectric substrate 20 near the lens system 2. As described above, by using a high-hardness material such as sapphire for the transparent dielectric substrate 20, the effect of protecting the lens system 2 or the imaging element 4 is increased. For example, in the color filter 3, R (red), G (green), and B (blue) three color filters are arranged in a matrix, and R (red) is arranged directly above each pixel of the image sensor 4 , G (green) and B (blue) filters. The imaging element 4 receives light from a subject that has passed through the lens system 2, the filter 1a, and the color filter 3. The imaging device 100 generates an image based on information related to electric charges generated by the light received in the imaging element 4. In addition, the color filter 3 and the imaging element 4 may be integrated to form a color image sensor.

In the filter 1a, since the conditions (i-1) to (ix-1) described above are satisfied, the imaging device 100 provided with such a filter 1a can generate a good-quality image. In the filter 1a, if the conditions (i-2), (ii-2), (iv-2), (vi-2), (vii-2), and (viii-2) described above are further satisfied, The imaging device 100 can generate an image having a high degree of color reproducibility. In the filter 1a, if the conditions shown in at least one of Tables (I), (II), and (III) are satisfied, the shape of the spectral transmittance curve is changed even if the incident angle of light is changed. The variation is also small, which can effectively prevent color unevenness in the image generated by the imaging device 100.
Examples

The present invention will be described in more detail by way of examples. The present invention is not limited to the following examples.

＜ Transmittance spectrum measurement ＞
When an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, product name: V-670) was used to measure light having a wavelength of 300 nm to 1200 nm incident on the filters of the Examples and Comparative Examples, the semi-finished products thereof, or the laminated body of the Reference Example Transmission spectrum. For the filters of the Examples and Comparative Examples, a part of the semi-finished product, and a part of the Reference Example, the transmittance spectrum was measured when the incident angle of the incident light was set to 0 °, 30 °, and 40 °. For the laminated bodies of other semi-finished products and other reference examples, the transmittance spectrum was measured when the incident angle of incident light was set to 0 °.

<Example 1>
The coating liquid IRA1 was prepared as follows. 1.1 g of copper acetate monohydrate and 60 g of tetrahydrofuran (THF) were mixed and stirred for 3 hours. To the obtained liquid was added 2.3 g of phosphate ester (product name of Daiichi Pharmaceutical Co., Ltd .: Plysurf A208F) and stirred for 30 minutes. A solution was obtained. To 0.6 g of phenylphosphonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was added 10 g of THF and stirred for 30 minutes to obtain liquid B. Add liquid B while stirring liquid A, and stir at room temperature for 1 minute. After 45 g of toluene was added to the solution, the solution was stirred at room temperature for 1 minute to obtain a liquid C. Liquid C was placed in a flask, and heated in an oil bath adjusted to 120 ° C (manufactured by Tokyo R & D Co., Ltd., model: OSB-2100) while using a rotary evaporator (manufactured by Tokyo R & D Co., Ltd., model) : N-1110SF) was subjected to a solvent removal treatment for 25 minutes to obtain a D solution. The D liquid was taken out of the flask, and 4.4 g of a polysiloxane resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) was added and stirred at room temperature for 30 minutes to obtain a coating liquid IRA1.

The coating liquid IRA2 was prepared as follows. 2.25 g of copper acetate monohydrate and 120 g of tetrahydrofuran (THF) were mixed and stirred for 3 hours, and 1.8 g of phosphate ester (product name of Daiichi Pharmaceutical Co., Ltd .: Plysurf A208F) was added to the obtained liquid and stirred for 30 minutes, E liquid was obtained. To 1.35 g of butylphosphonic acid, 20 g of THF was added and stirred for 30 minutes to obtain F liquid. While stirring the E liquid, the F liquid was added, and after stirring at room temperature for 3 hours, 40 g of toluene was added. Thereafter, the solvent was evaporated in an environment of 85 ° C. for 7.5 hours to obtain a G liquid. 8.8 g of polysiloxane resin (manufactured by Shin-Etsu Chemical Industry Co., Ltd., product name: KR-300) was added to the G liquid and stirred for 3 hours to obtain a coating liquid IRA2.

The coating liquid IRA1 was applied to one of the main surfaces of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco) with a die coater, and then heated at 85 ° C for 3 hours in an oven. Heat treatment was performed at 125 ° C for 3 hours, followed by heat treatment at 150 ° C for 1 hour, and then heat treatment at 170 ° C for 3 hours to harden the coating film to form an infrared absorbing layer ira11. In the same manner, the coating liquid IRA1 was also applied to the main surface on the opposite side of the transparent glass substrate, and the coating film was hardened under the same conditions as described above to form the infrared absorption layer ira12. In this way, the semi-finished product α of the filter of Example 1 was obtained. The thickness of the infrared absorbing layer ira11 and the infrared absorbing layer ira12 is 0.2 mm in total. The transmittance spectrum of the semi-finished product α at an incident angle of 0 ° is shown in FIG. 3A. The semi-finished product α has the following characteristics (α1) to (α10). (Α1): The spectral transmittance at a wavelength of 390 nm is 39.3%.
(Α2): The spectral transmittance at a wavelength of 400 nm is 63.7%.
(Α3): The spectral transmittance at a wavelength of 450 nm is 85.7%.
(Α4): The spectral transmittance at a wavelength of 700 nm is 2.3%.
(Α5): The spectral transmittance at a wavelength of 715 nm is 0.9%.
(Α6): The spectral transmittance at a wavelength of 1100 nm is 12.1%.
(Α7): The spectral transmittance at a wavelength of 1200 nm is 49.1%.
(Α8): The average transmittance at a wavelength of 500 to 600 nm is 88.0%.
(Α9): The average transmittance at a wavelength of 700 to 800 nm is 0.5% or less.
(Α10): IR cutoff wavelength is 632 nm, UV cutoff wavelength is 394 nm. When the difference between IR cutoff wavelength and UV cutoff wavelength is regarded as the full width at half height of the penetration region, the penetration region The full width at half maximum is 238 nm.

A vacuum evaporation device was used to form a 500 nm-thick SiO ₂ vapor-deposited film (protective layer p1) on the infrared absorption layer ira11 of the semi-finished product α. In the same manner, a 500 nm-thick SiO ₂ vapor-deposited film (protective layer p2) was formed on the infrared absorption layer ira12 of the semi-finished product α. The coating liquid IRA2 was coated on the surface of the protective layer p1 by a die coater, and then heated in an oven at 85 ° C for 3 hours, followed by heat treatment at 125 ° C for 3 hours, and then at 150 ° C. A heat treatment was performed for 1 hour, and then a heat treatment was performed at 170 ° C for 3 hours to harden the coating film to form an infrared absorbing layer ira21. In addition, the coating liquid IRA2 was also applied on the surface of the protective layer p2 by a die coater, and the coating film was hardened under the same heating conditions to form an infrared absorbing layer ira22. In this way, a semi-finished product β is obtained. The thickness of the infrared absorbing layer ira21 and the infrared absorbing layer ira22 is 50 μm in total. The transmittance spectrum of the semi-finished product β at an incident angle of 0 ° is shown in FIG. 3B. The semi-finished product β has the following characteristics (β1) to (β10).
(Β1): The spectral transmittance at a wavelength of 390 nm is 38.2%.
(Β2): The spectral transmittance at a wavelength of 400 nm is 62.1%.
(Β3): The spectral transmittance at a wavelength of 450 nm is 84.0%.
(Β4): The spectral transmittance at a wavelength of 700 nm is 1.8%.
(Β5): The spectral transmittance at a wavelength of 715 nm is 0.6%.
(Β6): The spectral transmittance at a wavelength of 1100 nm is 1.2%.
(Β7): The spectral transmittance at a wavelength of 1200 nm is 10.1%.
(Β8): The average transmittance at a wavelength of 500 to 600 nm is 87.2%.
(Β9): The average transmittance at a wavelength of 700 to 800 nm is 0.5% or less.
(Β10): IR cut-off wavelength is 632 nm, UV cut-off wavelength is 394 nm. When the difference between the IR cut-off wavelength and the UV cut-off wavelength is taken as the half-width of the penetration region, the half-width of the penetration region is 237 nm .

A vacuum deposition device was used to form a 500 nm-thick SiO ₂ vapor-deposited film (protective layer p3) on the infrared absorption layer ira22 of the semi-finished product β.

The coating liquid UVA1 was prepared in the following manner. As the ultraviolet absorbing substance, a benzophenone-based ultraviolet absorbing substance that has less absorption of light in the visible light region and is soluble in MEK (methyl ethyl ketone) is used. This ultraviolet absorbing substance was dissolved in MEK as a solvent, and 60% by weight of polyvinyl butyral (PVB) as a solid content was added, and the mixture was stirred for 2 hours to obtain a coating liquid UVA1. The coating liquid UVA1 was applied by spin coating on the protective layer p3, and heated at 140 ° C for 30 minutes to harden to form an ultraviolet absorbing layer uva1. The thickness of the ultraviolet absorbing layer uva1 is 6 μm. In addition, a UV-absorbing layer having a thickness of 6 μm was formed on the surface of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco) by using the coating liquid UVA1 by spin coating to obtain a laminated body of Reference Example 1. The transmittance spectrum of the laminated body of Reference Example 1 is shown in FIG. 3C. The laminated body of Reference Example 1 has the following characteristics (r1) to (r3).
(R1): The transmittance at a wavelength of 350 to 390 nm is 0.5% or less.
(R2): The transmittance at a wavelength of 400 nm is 12.9%, the transmittance at 410 nm is 51.8%, the transmittance at 420 nm is 77.1%, and the transmittance at 450 nm is 89.8%.
(R3): The average transmittance at a wavelength of 450 to 750 nm is 91.0%.

An anti-reflection film ar1 was formed on the infrared absorbing layer ira21 using a vacuum evaporation device. Further, an anti-reflection film ar2 was formed on the ultraviolet absorbing layer uva1 using a vacuum evaporation device. The anti-reflection film ar1 and the anti-reflection film ar2 are films having the same specifications and alternately laminated with SiO ₂ and TiO _{2. The} number of layers in the anti-reflection film ar1 and the anti-reflection film ar2 is 7 layers, and the total film thickness is Approximately 0.4 μm. In this way, the optical filter of Example 1 was obtained. An anti-reflection film was formed on one side of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco) under the same conditions as the film formation of the anti-reflection film ar1 to obtain a laminate of Reference Example 2. The transmittance spectrum of the laminated body of Reference Example 2 is shown in FIG. 3D. The laminated body of Reference Example 2 has the following characteristics (s1) to (s4).
(S1): When the incident angle of light is 0 °, the transmittance at a wavelength of 350 nm is 73.4%, the transmittance at a wavelength of 380 nm is 88.9%, the transmittance at a wavelength of 400 nm is 95.3%, and the wavelength The average transmittance of 400 to 700 nm is 95.3%, and the transmittance of wavelength 715 nm is 95.7%.
(S2): When the incident angle of light is 30 °, the transmittance at a wavelength of 350 nm is 78.5%, the transmittance at a wavelength of 380 nm is 92.0%, the transmittance at a wavelength of 400 nm is 94.5%, and the wavelength The average transmittance of 400 ~ 700 nm is 94.3%, and the transmittance of wavelength 715 nm is 94.6%.
(S3): When the incident angle of light is 40 °, the transmittance at a wavelength of 350 nm is 82.3%, the transmittance at a wavelength of 380 nm is 93.3%, the transmittance at a wavelength of 400 nm is 94.3%, and the wavelength The average transmittance of 400 to 700 nm is 94.0%, and the transmittance of wavelength 715 nm is 94.1%.
(S4): It does not depend on the incident angle of light, and there is no wave band that produces a local decrease in transmittance at a wavelength of 400 to 700 nm.

The transmittance spectrum of the filter of Example 1 is shown in FIG. 3E and Table 4. The filter of Example 1 has the characteristics shown in Table 5. The relationship between the difference in the spectral transmittance and the wavelength of the filter of Example 1 at two incident angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 4A. The relationship between the absolute value of the difference in the spectral transmittance of the filter of Example 1 and the wavelength from two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 4B. The relationship between the square of the difference in the spectral transmittance of the filter of Example 1 and the wavelength from two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 4C. From the transmittance spectrum of the filter of Example 1 at incidence angles of 0 °, 30 °, and 40 °, IE _{θ1 / θ2} ^{λ1 to λ2} and IAE _{θ1 / were} obtained according to the above formulas (1) to (3). _θ2 ^{λ1 to λ2} and ISE _{θ1 / θ2} ^{λ1 to λ2} . IE _{θ1 / θ2} ^{λ1 to λ2} , IAE _{θ1 / θ2} ^{λ1 to λ2,} and ISE _{θ1 / θ2} ^{λ1 to λ2} are in the variable range of the wavelength λ at λ1 = 350 and λ2 = 800, and at the wavelength λ of λ1 = 380 and λ2 = 530 The variable domains, the variable domains of the wavelength λ of λ1 = 450 and λ2 = 650, and the variable domains of the wavelength λ of λ1 = 530 and λ2 = 750 were obtained. The results are shown in Tables 6 to 8.

<Example 2>
A coating liquid IRA1 and a coating liquid IRA2 were prepared in the same manner as in Example 1. The coating liquid IRA1 was applied to one of the main surfaces of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco) with a die coater, and then heated at 85 ° C for 3 hours in an oven. Heat treatment was performed at 125 ° C for 3 hours, followed by heat treatment at 150 ° C for 1 hour, and then heat treatment at 170 ° C for 3 hours to harden the coating film to form an infrared absorbing layer ira11. In the same manner, the coating liquid IRA1 was also applied to the main surface on the opposite side of the transparent glass substrate, and the coating film was hardened under the same conditions as described above to form the infrared absorbing layer ira12. The thickness of the infrared absorbing layer ira11 and the infrared absorbing layer ira12 is 0.2 mm in total.

A vacuum evaporation device was used to form a 500 nm-thick SiO ₂ vapor-deposited film (protective layer p1) on the infrared absorbing layer ira11. In the same manner, a 500 nm-thick SiO ₂ vapor-deposited film (protective layer p2) was formed on the infrared absorbing layer ira12. The coating liquid IRA2 was coated on the surface of the protective layer p1 by a die coater, and then heated in an oven at 85 ° C for 3 hours, and then at 125 ° C for 3 hours, and then at 150 A heat treatment was performed at 1 ° C for 1 hour, and then a heat treatment was performed at 170 ° C for 3 hours to harden the coating film to form an infrared absorbing layer ira21. In addition, the coating liquid IRA2 was also applied to the surface of the protective layer p2 by a die coater, and the coating film was hardened under the same heating conditions to form an infrared absorbing layer ira22. The thickness of the infrared absorbing layer ira21 and the infrared absorbing layer ira22 is 50 μm in total.

A vacuum evaporation device was used to form a 500 nm-thick SiO ₂ vapor-deposited film (protective layer p3) on the infrared absorbing layer ira22. A coating liquid UVIRA1 containing an infrared absorbing pigment and an ultraviolet absorbing pigment was prepared as follows. The infrared absorbing pigment is a combination of a cyanine-based organic pigment and a squarylium-based organic pigment that has an absorption peak at a wavelength of 680 to 780 nm and is difficult to absorb light in the visible light region. The ultraviolet-absorbing pigment is a pigment composed of a benzophenone-based ultraviolet-absorbing substance that does not easily absorb light in the visible light region. Infrared absorbing pigments and ultraviolet absorbing pigments are soluble in MEK. An infrared absorbing dye and an ultraviolet absorbing dye were added to MEK as a solvent, and PVB as a matrix material was further added, followed by stirring for 2 hours to obtain a coating liquid UVIRA1. The blending ratio of the infrared absorbing pigment and the blending ratio of the ultraviolet absorbing pigment in the coating liquid UVIRA1 is determined in such a manner that the laminated body of Reference Example 3 exhibits the transmission spectrum shown in FIG. 5A. In the multilayer system of Reference Example 3, a coating liquid UVIRA1 was applied on a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco) by spin coating, and then the coating film was heated at 140 ° C for 30 minutes to make it Hardened and made. In the coating liquid UVIRA1, the mass ratio of the infrared absorption pigment to the solid content of PVB (the mass of the infrared absorption pigment: the mass of the solid content of PVB) was about 1: 199. The mass ratio of the ultraviolet absorbing dye to the solid content of PVB (the mass of the ultraviolet absorbing dye: the mass of the solid content of PVB) was about 40:60. The laminated body of Reference Example 3 has the following characteristics (t1) to (t5).
(T1): The transmittance at a wavelength of 700 nm is 8.7%, the transmittance at a wavelength of 715 nm is 13.6%, and the average transmittance at a wavelength of 700 to 800 nm is 66.2%.
(T2): 92.1% transmittance at a wavelength of 1100 nm.
(T3): The transmittance at a wavelength of 400 nm is 11.8%, the transmittance at 450 nm is 85.3%, and the average transmittance at a wavelength of 500 to 600 nm is 89.1%.
(T4): The IR cut-off wavelength of the wavelength 600 nm to 700 nm is 669 nm, the IR cut-off wavelength of the wavelength 700 nm to 800 nm is 729 nm, and the difference is 60 nm. The wavelength (maximum absorption wavelength) exhibiting the lowest transmittance at a wavelength of 600 nm to 800 nm is 705 nm.
(T5): The UV cut-off wavelength at a wavelength of 350 nm to 450 nm is 411 nm.

The coating liquid UVIRA1 was applied on the protective layer p3 by spin coating, and the coating film was heated at 140 ° C for 30 minutes to harden to form an infrared / ultraviolet absorbing layer uvira1. The thickness of the infrared and ultraviolet absorption layer uvira1 is 7 μm.

An anti-reflection film ar1 was formed on the infrared absorbing layer ira21 using a vacuum evaporation device. An anti-reflection film ar2 was formed on the infrared / ultraviolet absorbing layer uvira1 using a vacuum evaporation device. The anti-reflection film ar1 and the anti-reflection film ar2 are films having the same specifications and alternately laminated with SiO ₂ and TiO _{2. The} number of layers in the anti-reflection film ar1 and the anti-reflection film ar2 is 7 layers, and the total film thickness is Approximately 0.4 μm. In this way, the optical filter of Example 2 was obtained.

The transmittance spectrum of the filter of Example 2 is shown in FIG. 5B and Table 9. The filter of Example 2 has the characteristics shown in Table 10. The relationship between the difference in the spectral transmittance and the wavelength of the filter of Example 2 at two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 6A. The relationship between the absolute value of the difference in the spectral transmittance of the filter of Example 2 and the wavelength from two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 6B. The relationship between the square value of the difference in the spectral transmittance of the filter of Example 2 and the wavelength from two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 6C. From the transmittance spectrum of the filter of Example 2 with incident angles of 0 °, 30 °, and 40 °, IE _{θ1 / θ2} ^{λ1 to λ2} and IAE _{θ1 / were} obtained according to the above formulas (1) to (3). _θ2 ^{λ1 to λ2} and ISE _{θ1 / θ2} ^{λ1 to λ2} . IE _{θ1 / θ2} ^{λ1 to λ2} , IAE _{θ1 / θ2} ^{λ1 to λ2,} and ISE _{θ1 / θ2} ^{λ1 to λ2} are in the variable range of the wavelength λ at λ1 = 350 and λ2 = 800, and the wavelength λ of λ1 = 380 and λ2 = 530 The variable domains, the variable domains of the wavelength λ of λ1 = 450 and λ2 = 650, and the variable domains of the wavelength λ of λ1 = 530 and λ2 = 750 were obtained. The results are shown in Tables 11 to 13.

<Example 3>
A coating liquid IRA1 was prepared in the same manner as in Example 1. A die coater was applied to one of the main surfaces of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco), followed by heating treatment in an oven at 85 ° C for 3 hours, and then at 125 ° C for 3 hours. Heat treatment for 1 hour, followed by heat treatment at 150 ° C for 1 hour, and heat treatment at 170 ° C for 3 hours to harden the coating film to form an infrared absorbing layer ira11. In the same manner, the coating liquid IRA1 was also applied to the main surface on the opposite side of the transparent glass substrate, and the coating film was hardened under the same conditions as described above to form the infrared absorbing layer ira12. The thickness of the infrared absorbing layer ira11 and the infrared absorbing layer ira12 is 0.2 mm in total.

Next, an infrared reflecting film irr1 is formed on the infrared absorbing layer ira11 using a vacuum evaporation device. In the infrared reflection film irr1, 16 layers of SiO ₂ and TiO ₂ are alternately laminated. An infrared reflecting film was formed on one of the main surfaces of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco) under the same conditions as the formation of the infrared reflecting film irr1, and a laminated body of Reference Example 4 was produced. The transmittance spectrum of the laminated body of Reference Example 4 is shown in FIG. 7A. The laminated body of Reference Example 4 has the following characteristics (u1) to (u3).
(U1): When the incident angle of light is 0 °, the transmittance at a wavelength of 380 nm is 1.8%, the transmittance at a wavelength of 400 nm is 7.3%, and the average transmittance at a wavelength of 450 to 700 nm is 94.8 %, The lowest transmittance of the wavelength 450 ~ 700 nm is 93.4%, the average transmittance of the wavelength 700 ~ 800 nm is 94.0%, the transmittance of the wavelength 1100 nm is 4.1%, the IR cut-off wavelength is 902 nm, The UV cut-off wavelength is 410 nm.
(U2): When the incident angle of light is 30 °, the transmittance at a wavelength of 380 nm is 1.8%, the transmittance at a wavelength of 400 nm is 67.8%, and the average transmittance at a wavelength of 450 to 700 nm is 95.0 %, The lowest value of the transmittance at the wavelength of 450 ~ 700 nm is 93.8%, the average transmittance of the wavelength of 700 ~ 800 nm is 92.1%, the transmittance of the wavelength of 1100 nm is 5.3%, and the IR cut-off wavelength is 863 nm. The UV cut-off wavelength is 398 nm.
(U3): When the incident angle of light is 40 °, the transmittance at a wavelength of 380 nm is 4.0%, the transmittance at a wavelength of 400 nm is 90.2%, and the average transmittance at a wavelength of 450 to 700 nm is 94.1 %, The lowest value of the transmittance at the wavelength of 450 ~ 700 nm is 92.9%, the average transmittance of the wavelength of 700 ~ 800 nm is 91.5%, the transmittance of the wavelength of 1100 nm is 8.3%, and the IR cut-off wavelength is 837 nm. The UV cut-off wavelength is 391 nm.

A 500 nm thick SiO ₂ vapor-deposited film (protective layer p2) was formed on the infrared absorbing layer ira12. The coating liquid UVA1 used in Example 1 was applied on the protective layer p2 by spin coating, and the coating film was heated at 140 ° C for 30 minutes to harden to form an ultraviolet absorbing layer uva1. The thickness of the ultraviolet absorbing layer uva1 is 6 μm. An anti-reflection film ar2 is formed on the ultraviolet absorbing layer uva1 using a vacuum evaporation device. The anti-reflection film ar2 is a film in which SiO ₂ and TiO ₂ are alternately laminated. In the anti-reflection film ar2, the number of layers is 7 and the total film thickness is about 0.4 μm. In this way, the optical filter of Example 3 was obtained.

The transmittance spectrum of the filter of Example 3 is shown in FIG. 7B and Table 14. The filter of Example 3 has the characteristics shown in Table 15. The relationship between the difference in the spectral transmittance and the wavelength of the filter of Example 3 at two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 8A. The relationship between the absolute value of the difference in the spectral transmittance of the filter of Example 3 and the wavelength from two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 8B. The relationship between the square of the difference in the spectral transmittance of the filter of Example 3 and the wavelength from two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 8C. From the transmittance spectra of the optical filter of Example 3 at incidence angles of 0 °, 30 °, and 40 °, IE _{θ1 / θ2} ^{λ1 to λ2} and IAE _{θ1 / were} obtained according to the above formulas (1) to (3). _θ2 ^{λ1 to λ2} and ISE _{θ1 / θ2} ^{λ1 to λ2} . IE _{θ1 / θ2} ^{λ1 to λ2} , IAE _{θ1 / θ2} ^{λ1 to λ2,} and ISE _{θ1 / θ2} ^{λ1 to λ2} are in the variable range of the wavelength λ at λ1 = 350 and λ2 = 800, and at the wavelength λ of λ1 = 380 and λ2 = 530 The variable domains, the variable domains of the wavelength λ of λ1 = 450 and λ2 = 650, and the variable domains of the wavelength λ of λ1 = 530 and λ2 = 750 were obtained. The results are shown in Tables 16 to 18.

<Example 4>
A coating liquid IRA1 was prepared in the same manner as in Example 1. A die coater was applied to one of the main surfaces of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco), followed by heating treatment in an oven at 85 ° C for 3 hours, and then at 125 ° C for 3 hours. Heat treatment for 1 hour, followed by heat treatment at 150 ° C for 1 hour, and heat treatment at 170 ° C for 3 hours to harden the coating film to form an infrared absorbing layer ira11. In the same manner, the coating liquid IRA1 was also applied to the main surface on the opposite side of the transparent glass substrate, and the coating film was hardened under the same conditions as described above to form the infrared absorbing layer ira12. The thickness of the infrared absorbing layer ira11 and the infrared absorbing layer ira12 is 0.2 mm in total.

Next, in the same manner as in Example 3, an infrared reflecting film irr1 was formed on the infrared absorbing layer ira11 using a vacuum evaporation device. In the infrared reflection film irr1, 16 layers of SiO ₂ and TiO ₂ are alternately laminated.

A 500 nm thick SiO ₂ vapor-deposited film (protective layer p2) was formed on the infrared absorbing layer ira12. Under the same conditions as in Example 2, the coating liquid UVIRA1 used in Example 2 was coated on the protective layer p2, and the coating film was heated at 140 ° C for 30 minutes to harden to form an infrared and ultraviolet absorbing layer. uvira1. The thickness of the infrared and ultraviolet absorption layer uvira1 is 7 μm. An anti-reflection film ar2 was formed on the infrared / ultraviolet absorbing layer uvira1 using a vacuum evaporation device. The anti-reflection film ar2 is a film in which SiO ₂ and TiO ₂ are alternately laminated. In the anti-reflection film ar2, the number of layers is 7 and the total film thickness is about 0.4 μm. In this way, the optical filter of Example 4 was obtained.

The transmittance spectrum of the filter of Example 4 is shown in FIG. 9 and Table 19. The filter of Example 4 has the characteristics shown in Table 20. The relationship between the difference in spectral transmittance and the wavelength of the filter of Example 4 at two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 10A. The relationship between the absolute value of the difference in the spectral transmittance of the filter of Example 4 and the wavelength between two incident angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 10B. The relationship between the square value of the difference in the spectral transmittance of the filter of Example 4 and the wavelength at two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 10C. From the transmittance spectra of the filter of Example 4 with incident angles of 0 °, 30 °, and 40 °, IE _{θ1 / θ2} ^{λ1 to λ2} and IAE _{θ1 / were} obtained according to the above formulas (1) to (3). _θ2 ^{λ1 to λ2} and ISE _{θ1 / θ2} ^{λ1 to λ2} . IE _{θ1 / θ2} ^{λ1 to λ2} , IAE _{θ1 / θ2} ^{λ1 to λ2,} and ISE _{θ1 / θ2} ^{λ1 to λ2} are in the variable range of the wavelength λ at λ1 = 350 and λ2 = 800, and the wavelength λ of λ1 = 380 and λ2 = 530 The variable domains, the variable domains of the wavelength λ of λ1 = 450 and λ2 = 650, and the variable domains of the wavelength λ of λ1 = 530 and λ2 = 750 were obtained. The results are shown in Tables 21 to 23.

<Example 5>
A coating liquid IRA1 and a coating liquid IRA2 were prepared in the same manner as in Example 1. A die coater was applied to one of the main surfaces of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco), followed by heating treatment in an oven at 85 ° C for 3 hours, and then at 125 ° C for 3 hours. Heat treatment for 1 hour, followed by heat treatment at 150 ° C for 1 hour, and heat treatment at 170 ° C for 3 hours to harden the coating film to form an infrared absorbing layer ira11. In the same manner, the coating liquid IRA1 was also applied to the main surface on the opposite side of the transparent glass substrate, and the coating film was hardened under the same conditions as described above to form the infrared absorbing layer ira12. The thickness of the infrared absorbing layer ira11 and the infrared absorbing layer ira12 is 0.4 mm in total.

A vacuum evaporation device was used to form a 500 nm-thick SiO ₂ vapor-deposited film (protective layer p1) on the infrared absorbing layer ira11. In the same manner, a 500 nm-thick SiO ₂ vapor-deposited film (protective layer p2) was formed on the infrared absorbing layer ira12. The coating liquid IRA2 was applied to the surface of the protective layer p1 by a die coater, and then heated in an oven at 85 ° C for 3 hours, followed by heat treatment at 125 ° C for 3 hours, and then at 150 ° C. A heat treatment was performed at 1 ° C for 1 hour, and then a heat treatment was performed at 170 ° C for 3 hours to harden the coating film to form an infrared absorbing layer ira21. In addition, the coating liquid IRA2 was also applied on the surface of the protective layer p2 by a die coater, and the coating film was hardened under the same heating conditions to form an infrared absorbing layer ira22 to obtain a semi-finished product δ. The transmittance spectrum of the semi-finished product δ at an incident angle of 0 ° C is shown in Fig. 11A. The semi-finished product δ has the following characteristics (δ1) to (δ10).
(Δ1): The spectral transmittance at a wavelength of 390 nm is 15.8%.
(Δ2): The spectral transmittance at a wavelength of 400 nm is 42.0%.
(Δ3): The spectral transmittance at a wavelength of 450 nm is 76.7%.
(Δ4): The spectral transmittance at a wavelength of 700 nm is 0.5% or less.
(Δ5): The spectral transmittance at a wavelength of 715 nm is 0.5% or less.
(Δ6): The spectral transmittance at a wavelength of 1100 nm is 0.5% or less.
(Δ7): The spectral transmittance at a wavelength of 1200 nm is 1.1%.
(Δ8): The average transmittance at a wavelength of 500 to 600 nm is 82.7%.
(Δ9): The average transmittance at a wavelength of 700 to 800 nm is 0.5% or less.
(Δ10): IR cut-off wavelength is 613 nm, UV cut-off wavelength is 404 nm. When the difference between the IR cut-off wavelength and the UV cut-off wavelength is taken as the half-width of the penetration region, the half-width of the penetration region is 209 nm .

An anti-reflection film ar1 was formed on the infrared absorbing layer ira21 using a vacuum evaporation device. An anti-reflection film ar2 was formed on the infrared absorbing layer ira22 using a vacuum evaporation device. The anti-reflection film ar1 and the anti-reflection film ar2 are films having the same specifications and alternately laminated with SiO ₂ and TiO _{2. The} number of layers in the anti-reflection film ar1 and the anti-reflection film ar2 is 7 layers, and the total film thickness is Approximately 0.4 μm. In this way, the filter of Example 5 was obtained.

The transmittance spectrum of the filter of Example 5 is shown in FIG. 11B and Table 24. The filter of Example 5 has the characteristics shown in Table 25. The relationship between the difference in the spectral transmittance and the wavelength of the filter of Example 5 at two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 12A. The relationship between the absolute value of the difference in the spectral transmittance of the filter of Example 5 and the wavelength at two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 12B. The relationship between the square of the difference in the spectral transmittance of the filter of Example 5 and the wavelength from two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 12C. From the transmittance spectra of the optical filter of Example 5 with incident angles of 0 °, 30 °, and 40 °, IE _{θ1 / θ2} ^{λ1 to λ2} and IAE _{θ1 / were} obtained according to the above formulas (1) to (3). _θ2 ^{λ1 to λ2} and ISE _{θ1 / θ2} ^{λ1 to λ2} . IE _{θ1 / θ2} ^{λ1 to λ2} , IAE _{θ1 / θ2} ^{λ1 to λ2,} and ISE _{θ1 / θ2} ^{λ1 to λ2} are in the variable range of the wavelength λ at λ1 = 350 and λ2 = 800, and at the wavelength λ of λ1 = 380 and λ2 = 530 The variable domains, the variable domains of the wavelength λ of λ1 = 450 and λ2 = 650, and the variable domains of the wavelength λ of λ1 = 530 and λ2 = 750 were obtained. The results are shown in Tables 26 to 28.

〈Comparative example 1〉
On a main surface of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco), a vacuum evaporation device was used to alternately laminate 24 layers of SiO ₂ and TiO ₂ to form an infrared reflecting film irr2 to obtain a semi-finished product ε. The transmittance spectrum of the semi-finished product ε is shown in Fig. 13A. The semi-finished product ε has the following characteristics (ε1) to (ε3).
(Ε1): When the incident angle of light is 0 °, the transmittance at a wavelength of 380 nm is 0.5% or less, the transmittance at a wavelength of 400 nm is 3.1%, and the average transmittance at a wavelength of 450 to 600 nm 94.1%, the lowest value of the transmittance at the wavelength of 450 to 600 nm is 92.6%, the transmittance of the wavelength of 700 nm is 86.2%, the transmittance of the wavelength of 715 nm is 30.8%, and the average transmittance of the wavelength of 700 to 800 nm The rate is 12.4%, the transmission rate at a wavelength of 1100 nm is less than 0.5%, the IR cutoff wavelength is 710 nm, and the UV cutoff wavelength is 410 nm.
(Ε2): When the incident angle of light is 30 °, the transmittance at a wavelength of 380 nm is 1.7%, the transmittance at a wavelength of 400 nm is 77.7%, and the average transmittance at a wavelength of 450 to 600 nm is 94.1 %, The minimum transmittance of the wavelength of 450 ~ 600 nm is 93.0%, the transmittance of the wavelength of 700 nm is 8.2%, the transmittance of the wavelength of 715 nm is 2.2%, and the average transmittance of the wavelength of 700 ~ 800 nm It is 1.1%, the transmittance at a wavelength of 1100 nm is 1.2%, the IR cut-off wavelength is 680 nm, and the UV cut-off wavelength is 397 nm.
(Ε3): When the incident angle of light is 40 °, the transmittance at a wavelength of 380 nm is 13.1%, the transmittance at a wavelength of 400 nm is 90.5%, and the average transmittance at a wavelength of 450 to 600 nm is 92.1 %, The lowest transmittance of the wavelength of 450 ~ 600 nm is 87.6%, the transmittance of the wavelength of 700 nm is 2.0%, the transmittance of the wavelength of 715 nm is 0.8%, and the average transmittance of the wavelength of 700 ~ 800 nm It is less than 0.5%, the transmission rate at the wavelength of 1100 nm is 5.4%, the IR cutoff wavelength is 661 nm, and the UV cutoff wavelength is 386 nm.

A coating liquid IRA3 containing an infrared absorbing pigment was prepared in the following manner. Infrared absorbing pigments are soluble in the combination of MEK's cyanine-based organic pigments and squarylium-based organic pigments. An infrared absorbing dye was added to MEK as a solvent, and PVB as a matrix material was further added, followed by stirring for 2 hours to obtain a coating liquid IRA3. The content of the matrix material in the solid content of the coating liquid IRA3 was 99% by mass. After the coating liquid IRA3 was applied to the other main surface of the semi-finished transparent glass substrate by spin coating, the coating film was heated at 140 ° C for 30 minutes to harden to form an infrared absorbing layer ira3. In addition, an infrared absorbing layer was formed on one of the main surfaces of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco) under the same conditions as the conditions for forming the infrared absorbing layer ira3 to obtain a laminate of Reference Example 5. The transmittance spectrum of the laminated body of Reference Example 5 at an incident angle of 0 ° is shown in FIG. 13B. The laminated body of Reference Example 5 has the following characteristics (v1) to (v4).
(V1): The transmittance at a wavelength of 700 nm is 2.0%, the transmittance at a wavelength of 715 nm is 2.6%, and the average transmittance at a wavelength of 700 to 800 nm is 15.9%.
(V2): The transmission rate at the wavelength of 1100 nm is 91.1%.
(V3): The transmittance at a wavelength of 400 nm is 78.2%, the transmittance at 450 nm is 83.8%, and the average transmittance at a wavelength of 500 to 600 nm is 86.9%.
(V4): IR cut-off wavelength of 600 nm to 700 nm is 637 nm, IR cut-off wavelength of wavelength 700 nm to 800 nm is 800 nm, the difference between these IR cut-off wavelengths is 163 nm, and wavelength of 600 to 800 nm The maximum absorption wavelength is 706 nm.

An anti-reflection film ar1 was formed on the infrared absorbing layer ira3 in the same manner as in Example 1 using a vacuum evaporation device to obtain a filter of Comparative Example 1.

The transmittance spectrum of the filter of Comparative Example 1 is shown in FIG. 13C and Table 29. The filter of Comparative Example 1 has the characteristics shown in Table 30. The relationship between the difference in spectral transmittance and the wavelength of the filter of Comparative Example 1 at two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 14A. The relationship between the absolute value of the difference in the spectral transmittance of the filter of Comparative Example 1 and the wavelength from two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 14B. The relationship between the square of the difference in the spectral transmittance of the filter of Comparative Example 1 and the wavelength from two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 14C. From the transmittance spectra of the filter of Comparative Example 1 at incidence angles of 0 °, 30 °, and 40 °, IE _{θ1 / θ2} ^{λ1 to λ2} and IAE _{θ1 / were} obtained from the above formulas (1) to (3). _θ2 ^{λ1 to λ2} and ISE _{θ1 / θ2} ^{λ1 to λ2} . IE _{θ1 / θ2} ^{λ1 to λ2} , IAE _{θ1 / θ2} ^{λ1 to λ2,} and ISE _{θ1 / θ2} ^{λ1 to λ2} are in the variable range of the wavelength λ at λ1 = 350 and λ2 = 800, and at the wavelength λ of λ1 = 380 and λ2 = 530 The variable domains, the variable domains of the wavelength λ of λ1 = 450 and λ2 = 650, and the variable domains of the wavelength λ of λ1 = 530 and λ2 = 750 were obtained. The results are shown in Tables 31 to 33.

〈Comparative example 2〉
An infrared-absorbing glass substrate prepared to exhibit a transmittance spectrum shown in FIG. 15A at an incident angle of 0 °. This infrared-absorbing glass substrate has the following characteristics (g1) to (g10).
(G1): The spectral transmittance at a wavelength of 390 nm is 87.9%.
(G2): The spectral transmittance at a wavelength of 400 nm is 88.5%.
(G3): The spectral transmittance at a wavelength of 450 nm is 90.2%.
(G4): The spectral transmittance at a wavelength of 700 nm is 29.8%.
(G5): The spectral transmittance at a wavelength of 715 nm is 25.3%.
(G6): The spectral transmittance at a wavelength of 1100 nm is 32.5%.
(G7): The spectral transmittance at a wavelength of 1200 nm is 44.5%.
(G8): The average transmittance at a wavelength of 500 to 600 nm is 86.5%.
(G9): The average transmittance at a wavelength of 700 to 800 nm is 19.1%.
(G10): The IR cut-off wavelength is 653 nm, and the wavelength showing a 20% transmittance at a wavelength of 600 to 800 nm is 738 nm.

On one main surface of an infrared-absorbing glass substrate having a thickness of 210 μm, 20 layers of SiO ₂ and TiO ₂ were alternately laminated using a vacuum evaporation device to form an infrared reflective film irr3, to obtain a semi-finished product ζ. An infrared reflective film was formed on one of the main surfaces of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco) under the same conditions as those for forming the infrared reflective film irr3, to obtain a laminated body of Reference Example 6. The transmittance spectrum of the laminated body of Reference Example 6 is shown in FIG. 15B. The laminated body of Reference Example 6 has the following characteristics (w1) to (w3).
(W1): When the incident angle of light is 0 °, the transmittance at a wavelength of 380 nm is 0.5% or less, the transmittance at a wavelength of 400 nm is 0.5% or less, and the average transmittance at a wavelength of 450 to 600 nm It is 95.2%, the minimum value of the transmittance at the wavelength of 450 to 600 nm is 93.7%, the average transmittance of the wavelength of 700 to 800 nm is 4.7%, the transmittance of the wavelength of 1100 nm is less than 0.5%, and the IR cutoff wavelength is 702 nm, UV cut-off wavelength is 411 nm.
(W2): When the incident angle of light is 30 °, the transmittance at a wavelength of 380 nm is 1.7%, the transmittance at a wavelength of 400 nm is 77.7%, and the average transmittance at a wavelength of 450 to 600 nm is 94.1 %, The lowest value of the transmittance at the wavelength of 450 ~ 600 nm is 93.0%, the average transmittance of the wavelength of 700 ~ 800 nm is 1.1%, the transmittance of the wavelength of 1100 nm is 1.2%, and the IR cut-off wavelength is 680 nm. The UV cut-off wavelength is 397 nm.
(W3): When the incident angle of light is 40 °, the transmittance at a wavelength of 380 nm is 13.1%, the transmittance at a wavelength of 400 nm is 90.5%, and the average transmittance at a wavelength of 450 to 600 nm is 92.1 %, The minimum transmittance of the wavelength 450 ~ 600 nm is 87.6%, the average transmittance of the wavelength 700 ~ 800 nm is less than 0.5%, the transmittance of the wavelength 1100 nm is 5.4%, and the IR cut-off wavelength is 661 nm The UV cut-off wavelength is 386 nm.

A coating liquid UVIRA2 containing an infrared absorbing pigment and an ultraviolet absorbing pigment was prepared as follows. The ultraviolet-absorbing pigment is a pigment composed of a benzophenone-based ultraviolet-absorbing substance that does not easily absorb light in the visible light region. A combination of infrared absorbing pigment-based cyanine-based organic pigments and squarylium-based organic pigments. Infrared absorbing pigments and ultraviolet absorbing pigments are soluble in MEK. The infrared absorbing dye and the ultraviolet absorbing dye were added to MEK as a solvent, and PVB as a matrix material was further added, followed by stirring for 2 hours to obtain a coating liquid UVIRA2. The content of PVB in the solid content of the coating liquid UVIRA2 was 60% by mass. The coating liquid UVIRA2 was applied to the other main surface of the semi-finished product ζ, and the coating film was heated to harden it to form an infrared / ultraviolet absorbing layer uvira2. The thickness of the infrared and ultraviolet absorption layer uvira2 is 7 μm. On one of the main surfaces of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco), a coating liquid UVIRA2 was used, and an infrared and ultraviolet absorbing layer was formed under the same conditions as those for forming the infrared and ultraviolet absorbing layer uvira2 to obtain The laminated body of Reference Example 7. The transmittance spectrum of the laminated body of Reference Example 7 at an incident angle of 0 ° is shown in FIG. 15C. The laminated body of Reference Example 7 has the following characteristics (p1) to (p5).
(P1): The transmittance at a wavelength of 700 nm is 4.9%, the transmittance at a wavelength of 715 nm is 8.4%, and the average transmittance at a wavelength of 700 to 800 nm is 63.9%.
(P2): 92.3% transmission at 1100 nm.
(P3): The transmittance at a wavelength of 400 nm is 12.6%, the transmittance at 450 nm is 84.4%, and the average transmittance at a wavelength of 500 to 600 nm is 88.7%.
(P4): The IR cut-off wavelength of wavelength 600 nm to 700 nm is 664 nm, the IR cut-off wavelength of wavelength 700 nm to 800 nm is 731 nm, and the difference is 67 nm. The wavelength (maximum absorption wavelength) exhibiting the lowest transmittance at a wavelength of 600 nm to 800 nm is 705 nm.
(P5): The UV cut-off wavelength of the wavelength from 350 nm to 450 nm is 411 nm.

An anti-reflection film ar1 was formed on the infrared / ultraviolet absorbing layer uvira2 in the same manner as in Example 1 using a vacuum evaporation device. The anti-reflection film ar1 is a film in which SiO ₂ and TiO ₂ are alternately laminated. In the anti-reflection film ar1, the number of layers is 7 and the total film thickness is about 0.4 μm. In this way, the filter of Comparative Example 2 was obtained.

The transmittance spectrum of the filter of Comparative Example 2 is shown in FIG. 15D and Table 34. The filter of Comparative Example 2 has the characteristics shown in Table 35. The relationship between the difference in spectral transmittance and the wavelength of the filter of Comparative Example 2 at two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 16A. The relationship between the absolute value of the difference in the spectral transmittance of the filter of Comparative Example 2 and the wavelength from two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 16B. The relationship between the square value of the difference in the spectral transmittance of the filter of Comparative Example 2 and the wavelength from two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 16C. From the transmittance spectra of the filter of Comparative Example 2 at incidence angles of 0 °, 30 °, and 40 °, IE _{θ1 / θ2} ^{λ1 to λ2} and IAE _{θ1 / were} obtained from the above formulas (1) to (3). _θ2 ^{λ1 to λ2} and ISE _{θ1 / θ2} ^{λ1 to λ2} . IE _{θ1 / θ2} ^{λ1 to λ2} , IAE _{θ1 / θ2} ^{λ1 to λ2,} and ISE _{θ1 / θ2} ^{λ1 to λ2} are in the variable range of the wavelength λ at λ1 = 350 and λ2 = 800, and at the wavelength λ of λ1 = 380 and λ2 = 530 The variable domains, the variable domains of the wavelength λ of λ1 = 450 and λ2 = 650, and the variable domains of the wavelength λ of λ1 = 530 and λ2 = 750 were obtained. The results are shown in Tables 36 to 38.

〈Comparative example 3〉
A coating liquid IRA1 and a coating liquid IRA2 were prepared in the same manner as in Example 1. The coating liquid IRA1 was applied to one of the main surfaces of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco) with a die coater, and then heated at 85 ° C for 3 hours in an oven. Heat treatment was performed at 125 ° C for 3 hours, followed by heat treatment at 150 ° C for 1 hour, and then heat treatment at 170 ° C for 3 hours to harden the coating film to form an infrared absorbing layer ira11. In the same manner, the coating liquid IRA1 was also applied to the main surface on the opposite side of the transparent glass substrate, and the coating film was hardened under the same conditions as described above to form the infrared absorbing layer ira12. In this way, a semi-finished product γ of the filter of Comparative Example 3 was obtained. The thickness of the infrared absorbing layer ira11 and the infrared absorbing layer ira12 is 0.2 mm in total. The transmittance spectrum of the semi-finished product γ at an incident angle of 0 ° is shown in FIG. 17A. The semi-finished product γ has the following characteristics (γ1) to (γ10).
(Γ1): The spectral transmittance at a wavelength of 390 nm is 35.4%.
(Γ2): The spectral transmittance at a wavelength of 400 nm is 60.9%.
(Γ3): The spectral transmittance at a wavelength of 450 nm is 84.9%.
(Γ4): The spectral transmittance at a wavelength of 700 nm is 1.4%.
(Γ5): The spectral transmittance at a wavelength of 715 nm is 0.5%.
(Γ6): The spectral transmittance at a wavelength of 1100 nm is 9.4%.
(Γ7): The spectral transmittance at a wavelength of 1200 nm is 45.5%.
(Γ8): The average transmittance at a wavelength of 500 to 600 nm is 87.6%.
(Γ9): The average transmittance at a wavelength of 700 to 800 nm is 0.5% or less.
(Γ10): The IR cut-off wavelength is 629 nm and the UV cut-off wavelength is 395 nm. When the difference between the IR cut-off wavelength and the UV cut-off wavelength is regarded as the half-width of the penetration region, the half-width of the penetration region is 234 nm .

A vapor-deposited film (protective layer p2) of SiO _{2 with a} thickness of 500 nm was formed on the infrared absorption layer ira12 of the semi-finished product γ. On the protective layer p2, the coating liquid UVA1 used in Example 1 was applied by spin coating, and the coating film was heated at 140 ° C for 30 minutes to harden to form an ultraviolet absorbing layer uva1. The thickness of the ultraviolet absorbing layer uva1 is 6 μm.

An anti-reflection film ar1 is formed on the infrared absorbing layer ira11 using a vacuum evaporation device. An anti-reflection film ar2 is formed on the ultraviolet absorbing layer uva1 using a vacuum evaporation device. The anti-reflection film ar1 and the anti-reflection film ar2 are films having the same specifications and alternately laminated with SiO ₂ and TiO _{2. The} number of layers in the anti-reflection film ar1 and the anti-reflection film ar2 is 7 layers, and the total film thickness is Approximately 0.4 μm. In this way, the filter of Comparative Example 3 was obtained.

The transmittance spectrum of the filter of Comparative Example 3 is shown in FIG. 17B and Table 39. The filter of Comparative Example 3 has the characteristics shown in Table 40. The relationship between the difference in spectral transmittance and the wavelength of the filter of Comparative Example 3 at two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 18A. The relationship between the absolute value of the difference in the spectral transmittance of the filter of Comparative Example 3 and the wavelength between two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 18B. The relationship between the square value of the difference in the spectral transmittance of the filter of Comparative Example 3 and the wavelength from two incidence angles selected from 0 °, 30 °, and 40 ° is shown in FIG. 18C. From the transmittance spectra of the filter of Comparative Example 3 at incidence angles of 0 °, 30 °, and 40 °, IE _{θ1 / θ2} ^{λ1 to λ2} and IAE _{θ1 / were} obtained from the above formulas (1) to (3). _θ2 ^{λ1 to λ2} and ISE _{θ1 / θ2} ^{λ1 to λ2} . IE _{θ1 / θ2} ^{λ1 to λ2} , IAE _{θ1 / θ2} ^{λ1 to λ2,} and ISE _{θ1 / θ2} ^{λ1 to λ2} are in the variable range of the wavelength λ at λ1 = 350 and λ2 = 800, and at the wavelength λ of λ1 = 380 and λ2 = 530 The variable domain, the variable domain of the wavelength λ of λ1 = 450 and λ2 = 650, and the variable domain of the wavelength λ of λ1 = 530 and λ2 = 750 were obtained. The results are shown in Tables 41 to 43.

In the filters of Examples 1 to 5, the above conditions (i-1) to (ix-1) are satisfied. The filters shown in Examples 1 to 5 have sufficiently low transmittance in a wavelength range above 700 nm, and the filters of Examples 1 to 5 can shield near infrared rays well. Compared with the filter of Example 1, the filter of Example 2 exhibits a lower transmittance in a wavelength range above 700 nm. In the filter of Example 2, by including an infrared absorbing pigment, the transmittance in the visible light region was about 2 points lower than that of the filter of Example 1. However, it is considered that there is no problem in practical use. In the optical filter of Example 5, compared with the optical filters of other Examples, the transmittance near the wavelength of 400 nm is higher, but it is 44.9% or less.

In the filters of Examples 1 to 5, the conditions shown in the above Tables (I) to (III) were satisfied. In particular, the spectral transmittances of the filters of Examples 1, 2, and 5 for incident angles of 0 °, 30 °, and 40 ° are unchanged in the variable domains of each wavelength λ. Therefore, in the filters of Examples 1, 2, and 5, IE _{θ1 / θ2} ^{λ1 to λ2} are sufficiently smaller than the upper limit values described in Tables (I) to (III), and sufficiently sufficient for the lower limit values. Big. In addition, in the filters of Examples 1, 2, and 5, the values of IAE _{θ1 / θ2} ^{λ1 to λ2} and ISE _{θ1 / θ2} ^{λ1 to λ2} are relative to the upper limits of Tables (II) and (III). Small enough. In the infrared-reflective film of the filters of Examples 3 and 4, the boundary between the band of light transmitted by the incident angle of 40 ° and the band of reflected light by the incident angle of 40 ° was set to be near 850 nm . Therefore, on the long wavelength side of the wavelength range of 350 nm to 800 nm (wavelength range of 600 nm to 800 nm), the spectral splitting of the filters of Examples 3 and 4 at the incident angles of 0 °, 30 °, and 40 ° There is almost no change in transmittance. On the other hand, in the filters of Examples 3 and 4, the larger the incident angle of light, the higher the transmittance around the wavelength of 400 nm. This effect is in the filters of Examples 3 and 4, and appears in IE _0/30 ^{380 to 530} , IE _0/40 ^{380 to 530} , IAE _0/30 ^{380 to 530} , IAE _0/40 ^{380 to 530} , ISE _0/30 ^{380 to 530} and ISE _0/40 ^{380 to 530} . The spectral transmittance of the filters of Examples 3 and 4 near the wavelength of 530 nm at an incident angle of 30 ° is higher than the wavelengths of the filters of Examples 3 and 4 at an incident angle of 0 ° and an incident angle of 40 ° Spectroscopic transmission near 530 nm. This effect appears in IE _0/30 ^{450 to 650} , IE _30/40 ^{450 to 650} , IAE _0/30 ^{450 to 650} , IAE _30/40 ^{450 to 650} , ISE _0/30 ^{450 to 650,} and ISE _30/40 ^{450 to 650} . However, the more any of the effects satisfies the conditions shown in Tables (I) to (III), the smaller it is. Therefore, it is considered that when the filters of Examples 1 to 5 are assembled in a camera module, even if light is incident on the filter within an angle of incidence ranging from 0 ° to 40 °, it will not be used for shooting. Color unevenness is generated inside the image.

According to the filter of Comparative Example 1, the boundary between the visible light region adjacent to the near-infrared region and the band in which light is transmitted and the band in which light is shielded are determined by the infrared absorbing layer ira3. However, since the absorption band of the infrared absorption layer ira3 is narrow, the transmittance spectrum of the filter of Comparative Example 1 is affected by the shift of the reflection band of the infrared reflection film to the short wavelength side as the incident angle of light becomes larger. . In addition, the filter of Comparative Example 1 has insufficient light absorption capacity in the ultraviolet region, and the filter of Comparative Example 1 essentially shields light in the ultraviolet region only by the infrared reflecting film irr2. Therefore, the filter of Comparative Example 1 is located in the ultraviolet region, and is strongly affected by the shift of the reflection frequency band to the short wavelength side due to the incident angle of light. Therefore, the filter of Comparative Example 1 did not satisfy the conditions (i-1), (ii-1), (vi-1), and (vii-1) described above. Furthermore, the filter of Comparative Example 1 was at 400 nm. The nearby spectral transmittance varies greatly between an incident angle of 0 ° and an incident angle of 30 °. In addition, the spectral transmittance of the filter of Comparative Example 1 near 650 nm largely varies between an incident angle of 0 ° and an incident angle of 40 °. In addition, the spectral transmittance of the filter of Comparative Example 1 in the range of 450 nm to 650 nm is between an incident angle of 0 ° and an incident angle of 40 °, and an incident angle of 30 ° and 40 ° The incident angle varies greatly locally. IAE _30/40 ^{350 to 800} , ISE _30/40 ^{380 to 800} , IAE _30/40 ^{380 to 530} , ISE _30/40 ^{380 to 530} , IE _30/40 ^{450 to 650} , IAE _30/40 ^{450 to 650} , IE _{30 / 40} ^{530 to 750} , IAE _30/40 ^{530 to 750,} and ISE _30/40 ^{530 to 750 do} not fall within the ranges shown in Tables (I) to (III). Therefore, when the filter of Comparative Example 1 is incorporated in an imaging device, there is a concern that strong color unevenness is generated in a narrow range of the obtained image.

In the filter of Comparative Example 2, in the region adjacent to the near-infrared region in the visible light region, the near-infrared region, and the ultraviolet region, the boundary between the band of light transmission and the shielded light band is formed by the infrared and ultraviolet absorption layer uvira2 And ok. However, since the infrared / ultraviolet absorbing layer uvira2 has a narrow absorption band in the near-infrared region, in the filter of Comparative Example 2, IE _30/40 ^{350 to 800} shows a larger value. In addition, the transmittance spectrum of the filter of Comparative Example 2 with an incident angle of 40 ° is a local variation (moiré) of the visible spectral transmittance in the visible light region. Therefore, IE _30/40 ^{350 to 800} , IAE _30/40 ^{350 to 800} , ISE _30/40 ^{350 to 800} , IE _30/40 ^{380 to 530} , IAE _30/40 ^{380 to 530} , and IE _30/40 ^{450 to 650} , IAE _30/40 ^{450 to 650} , IE _30/40 ^{530 to 750,} and IAE _30/40 ^{530 to 750} become larger values. Therefore, when the filter of Comparative Example 2 is incorporated in an imaging device, there is a concern that a strong color unevenness is generated in a narrow range of the obtained image.

In the filter of Comparative Example 3, the conditions (vi-1) and (vii-1) described above were not satisfied. Therefore, it is difficult to say that the filter of Comparative Example 3 has desired characteristics in a wavelength range of 1100 to 1200 nm.

[Table 4]

[table 5]

[TABLE 6]

[TABLE 7]

[TABLE 8]

[TABLE 9]

[TABLE 10]

[TABLE 11]

[TABLE 12]

[TABLE 13]

[TABLE 14]

[Table 15]

[TABLE 16]

[TABLE 17]

[TABLE 18]

[TABLE 19]

[TABLE 20]

[TABLE 21]

[TABLE 22]

[TABLE 23]

[TABLE 24]

[TABLE 25]

[TABLE 26]

[TABLE 27]

[TABLE 28]

[TABLE 29]

[TABLE 30]

[TABLE 31]

[TABLE 32]

[TABLE 33]

[TABLE 34]

[TABLE 35]

[TABLE 36]

[TABLE 37]

[TABLE 38]

[TABLE 39]

[TABLE 40]

[TABLE 41]

[TABLE 42]

[TABLE 43]

1a ~ 1f‧‧‧ Filter

2‧‧‧ lens system

3‧‧‧ color filter

4‧‧‧ camera element

10‧‧‧ light absorbing layer

20‧‧‧ transparent dielectric substrate

30‧‧‧Anti-reflective film

40‧‧‧Reflective film

100‧‧‧ Camera (Camera Module)

Fig. 1A is a sectional view showing an example of an optical filter according to the present invention.

Fig. 1B is a sectional view showing another example of the optical filter of the present invention.

Fig. 1C is a sectional view showing still another example of the optical filter of the present invention.

FIG. 1D is a sectional view showing still another example of the optical filter of the present invention.

Fig. 1E is a sectional view showing still another example of the optical filter of the present invention.

FIG. 1F is a sectional view showing still another example of the optical filter of the present invention.

Fig. 2 is a cross-sectional view showing an example of an imaging device according to the present invention.

FIG. 3A is a transmittance spectrum of a semi-finished product of the filter of Example 1. FIG.

FIG. 3B is a transmittance spectrum of another semi-finished product of the filter of Example 1. FIG.

FIG. 3C is a transmittance spectrum of the laminated body of Reference Example 1. FIG.

FIG. 3D is a transmittance spectrum of the laminated body of Reference Example 2. FIG.

FIG. 3E is a transmittance spectrum of the filter of Example 1. FIG.

FIG. 4A is a graph showing a difference in spectral transmittance of the filter of Example 1 at different incident angles.

FIG. 4B is a graph showing the absolute value of the difference in the spectral transmittance of the filter of Example 1 at different incident angles.

FIG. 4C is a graph showing the square of the difference between the spectral transmittances of the filters of Example 1 at different incident angles.

FIG. 5A is a transmittance spectrum of the laminated body of Reference Example 3. FIG.

FIG. 5B is a transmittance spectrum of the filter of Example 2. FIG.

FIG. 6A is a graph showing a difference in spectral transmittance of the filter of Example 2 at different incident angles.

FIG. 6B is a graph showing the absolute value of the difference in the spectral transmittance of the filter of Example 2 at different incident angles.

FIG. 6C is a graph showing the square of the difference between the spectral transmittances of the filters of Example 2 at different incident angles.

FIG. 7A is a transmittance spectrum of the laminated body of Reference Example 4. FIG.

FIG. 7B is a transmittance spectrum of the filter of Example 3. FIG.

FIG. 8A is a graph showing the difference in the spectral transmittance of the filter of Example 3 at different incident angles.

FIG. 8B is a graph showing the absolute value of the difference in the spectral transmittance of the filter of Example 3 at different incident angles.

FIG. 8C is a graph showing the square of the difference in the spectral transmittance of the filter of Example 3 at different incident angles.

FIG. 9 is a transmittance spectrum of the filter of Example 4. FIG.

FIG. 10A is a graph showing a difference in spectral transmittance of the filter of Example 4 at different incident angles.

FIG. 10B is a graph showing the absolute value of the difference in the spectral transmittance of the filter of Example 4 at different incident angles.

FIG. 10C is a graph showing the square of the difference between the spectral transmittances of the filters of Example 4 at different incident angles.

FIG. 11A is a transmittance spectrum of a semi-finished product of the filter of Example 5. FIG.

FIG. 11B is a transmittance spectrum of the filter of Example 5. FIG.

FIG. 12A is a graph showing the difference in the spectral transmittance of the filter of Example 5 at different incident angles.

FIG. 12B is a graph showing the absolute value of the difference in the spectral transmittance of the filter of Example 5 at different incident angles.

FIG. 12C is a graph showing the square of the difference between the spectral transmittances of the filters of Example 5 at different incident angles.

FIG. 13A is a transmittance spectrum of a semi-finished product of the filter of Comparative Example 1. FIG.

FIG. 13B is a transmittance spectrum of the laminated body of Reference Example 5. FIG.

FIG. 13C is a transmittance spectrum of the filter of Comparative Example 1. FIG.

FIG. 14A is a graph showing a difference in spectral transmittance of the filter of Comparative Example 1 at different incident angles.

14B is a graph showing the absolute value of the difference in the spectral transmittance of the filter of Comparative Example 1 at different incident angles.

FIG. 14C is a graph showing the square of the difference in the spectral transmittance of the filter of Comparative Example 1 at different incident angles.

FIG. 15A is a transmittance spectrum of an infrared-absorbing glass substrate of a filter of Comparative Example 2. FIG.

FIG. 15B is a transmittance spectrum of the laminated body of Reference Example 6. FIG.

FIG. 15C is a transmittance spectrum of the laminated body of Reference Example 7. FIG.

FIG. 15D is a transmittance spectrum of the filter of Comparative Example 2. FIG.

FIG. 16A is a graph showing a difference in spectral transmittance of the filter of Comparative Example 2 at different incident angles.

16B is a graph showing the absolute value of the difference in the spectral transmittance of the filter of Comparative Example 2 at different incident angles.

16C is a graph showing the square of the difference in the spectral transmittance of the filter of Comparative Example 2 at different incident angles.

FIG. 17A is a transmittance spectrum of a semi-finished product of the filter of Comparative Example 3. FIG.

FIG. 17B is a transmittance spectrum of the filter of Comparative Example 3. FIG.

FIG. 18A is a graph showing a difference in spectral transmittance of the filter of Comparative Example 3 at different incident angles.

18B is a graph showing the absolute value of the difference in the spectral transmittance of the filter of Comparative Example 3 at different incident angles.

FIG. 18C is a graph showing the square of the difference in the spectral transmittance of the filter of Comparative Example 3 at different incident angles.

Claims (9)

An optical filter, It includes a light absorbing layer containing a light absorbing agent that absorbs at least a part of light in the near-infrared region, When light with a wavelength of 300 nm to 1200 nm is incident on the filter at incidence angles of 0 °, 30 °, and 40 °, the following conditions are satisfied: (I-1) The spectral transmittance at a wavelength of 390 nm is less than 20%; (Ii-1) The spectral transmittance at a wavelength of 400 nm is less than 45%; (Iii-1) The spectral transmittance at a wavelength of 450 nm is more than 75%; (Iv-1) The spectral transmittance at a wavelength of 700 nm is less than 3%; (V-1) The spectral transmittance of the wavelength of 715 nm is less than 1%; (Vi-1) The spectral transmittance at a wavelength of 1100 nm is less than 2%; (Vii-1) The spectral transmittance at a wavelength of 1200 nm is less than 15%; (Viii-1) The average transmittance at a wavelength of 500 to 600 nm is more than 80%; (Ix-1) The average transmittance at a wavelength of 700 to 800 nm is 0.5% or less. The filter according to claim 1, wherein when the light having a wavelength of 300 nm to 1200 nm is incident on the filter at incidence angles of 0 °, 30 °, and 40 °, the following conditions are further satisfied: (I-2) The spectral transmittance at a wavelength of 390 nm is less than 10%; (Ii-2) The spectral transmittance at a wavelength of 400 nm is less than 25%; (Iv-2) The spectral transmittance at a wavelength of 700 nm is less than 2.5%; (Vi-2) The spectral transmittance at a wavelength of 1100 nm is less than 1%; (Vii-2) The spectral transmittance at a wavelength of 1200 nm is less than 13%; (Viii-2) The average transmittance at a wavelength of 500 to 600 nm is 85% or more. The filter according to claim 1 or 2, wherein the spectral transmittance of the filter at a wavelength λ at an incident angle of θ ° is expressed as T _θ (λ), and a variable range of the wavelength λ is expressed The minimum and maximum values are expressed as λ1 [nm] and λ2 [nm], respectively, and the function of the wavelength λ as an integer n above 0 is expressed as λ (n) = (∆ other fonts are used in the file, please adjust the font ( Please set the Chinese characters to be new and detailed, the English characters to be set to Times New Roman). Λ × n ＋ λ1) [nm] (where other fonts are used in the ∆ file, please adjust the fonts (please set the Chinese characters to new details) Please set Times New Roman for English and Chinese characters. Λ = 1), for two incident angles θ1 ° and θ2 ° (θ1 <θ2) selected from 0 °, 30 °, and 40 °, λ1 = 350 And λ2 = 800 wavelength λ, λ1 = 380 and λ2 = 530 wavelength λ, λ1 = 450 and λ2 = 650 λ, and λ1 = 530 and λ2 = 750. For each variable domain of the variable domain, IE _{θ1 / θ2} ^{λ1 ~ λ2} defined by the following formula (1) satisfies the conditions shown in the following table (I); The filter according to any one of claims 1 to 3, wherein the spectral transmittance of the filter at a wavelength λ at an incident angle of θ ° is expressed as T _θ (λ), and the wavelength is The minimum and maximum values of the variable range of λ are expressed as λ1 [nm] and λ2 [nm], respectively, and the function of the wavelength λ with an integer n or greater than 0 is expressed as λ (n) = (∆ other fonts are used in the file, Please adjust the font (Chinese characters should be set to new detail style, English characters should be set to Times New Roman). Λ × n ＋ λ1) [nm] (where other fonts are used in the ∆ file, please adjust the font (Chinese characters please Set it as a new detail style and the English word as Times New Roman). Λ = 1), for two incident angles θ1 ° and θ2 ° selected from 0 °, 30 °, and 40 ° (θ1 <θ2), In the variable domains of the wavelengths λ1 = 350 and λ2 = 800, the variable domains of the wavelengths λ1 = 380 and λ2 = 530, the variable domains of the wavelengths λ1 = 450 and λ2 = 650, and λ1 = 530 and λ2 = For each of the variable domains of the wavelength λ of 750, IAE _{θ1 / θ2} ^{λ1 to λ2} defined by the following formula (2) satisfy the conditions shown in the following table (II); The filter according to any one of claims 1 to 4, wherein the spectral transmittance of the filter at a wavelength λ at an incident angle of θ ° is represented by T _θ (λ), and the wavelength is The minimum and maximum values of the variable range of λ are expressed as λ1 [nm] and λ2 [nm], respectively, and the function of the wavelength λ with an integer n or greater than 0 is expressed as λ (n) = (∆ other fonts are used in the file, Please adjust the font (Chinese characters should be set to new detail style, English characters should be set to Times New Roman). Λ × n ＋ λ1) [nm] (where other fonts are used in the ∆ file, please adjust the font (Chinese characters please Set it as a new detail style and the English word as Times New Roman). Λ = 1), for two incident angles θ1 ° and θ2 ° selected from 0 °, 30 °, and 40 ° (θ1 <θ2), In the variable domains of the wavelengths λ1 = 350 and λ2 = 800, the variable domains of the wavelengths λ1 = 380 and λ2 = 530, the variable domains of the wavelengths λ1 = 450 and λ2 = 650, and λ1 = 530 and λ2 = For each of the variable domains of the wavelength λ of 750, the ISE _{θ1 / θ2} ^{λ1 to λ2} defined by the following formula (3) satisfy the conditions shown in the following table (III); The optical filter according to any one of claims 1 to 5, wherein the light absorber is formed of phosphonic acid and copper ions. The filter according to claim 6, wherein the phosphonic acid comprises: a first phosphonic acid having an aryl group. The filter according to claim 7, wherein the phosphonic acid further includes a second phosphonic acid having an alkyl group. A camera device includes: Lens system An imaging element that receives light passing through the lens system; A color filter, which is arranged in front of the above-mentioned imaging element and has three color filters of R (red), G (green) and B (blue); and The filter according to any one of claims 1 to 8, which is disposed in front of the color filter.