Optical filter, optical device and light-absorbing composition

Abstract

The optical filter 1a has a first transmittance spectrum at 25°C satisfying the following (i), (ii), (iii), and (iv). (i) The minimum value of the transmittance in the range of wavelengths from 450 nm to 600 nm is 70% or greater. (ii) The maximum value of the transmittance in the range of wavelengths from 300 nm to 370 nm is 5% or less. (iii) The maximum value of the transmittance in the range of wavelengths from 800 nm to 1000 nm is 5% or less. (iv) The minimum value of the transmittance in the range of wavelengths from 1500 nm to 1700 nm is 60% or greater.

Description

Technical Field

[0001] This invention relates to filters, optical devices, and light-absorbing compositions. Background Technology

[0002] In imaging devices using solid-state imaging elements such as CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor), various filters are arranged in front of the solid-state imaging element to obtain images with good color reproduction. Typically, solid-state imaging elements have spectral sensitivity over a wide wavelength range from the ultraviolet to the infrared region. On the other hand, human visual sensitivity exists only in the visible light region. Therefore, techniques exist for arranging filters in front of the solid-state imaging element to block a portion of infrared or ultraviolet light in order to make the spectral sensitivity of the solid-state imaging element in the imaging device similar to human visual sensitivity.

[0003] Traditionally, such filters typically utilize light reflection based on dielectric multilayer films to block infrared or ultraviolet rays. However, in recent years, filters incorporating films containing light-absorbing agents have attracted attention. The transmittance characteristics of filters with light-absorbing agent films are less affected by the angle of incidence; therefore, even when light is incident obliquely on the filter in the imaging device, good images with minimal tonal variation can be obtained. Furthermore, light-absorbing filters that do not use reflective films can suppress ghosting or glare caused by multiple reflections based on reflective films, thus benefiting image quality in backlit conditions or night scene shooting. In addition, filters incorporating films containing light-absorbing agents are advantageous for miniaturization and thinning of imaging devices. Examples of such light-absorbing agents include those formed from phosphonic acid and copper ions.

[0004] For example, Patent Document 1 describes a filter containing a light absorber formed from a phosphonic acid having a phenyl or halophenyl group and copper ions.

[0005] Patent Document 2 describes a filter having a UV-IR absorption layer capable of absorbing infrared and ultraviolet light. The UV-IR absorption layer contains a UV-IR absorber formed from phosphonic acid and copper ions.

[0006] Patent document 3 describes an infrared cutoff filter having an organic pigment layer and a copper phosphonate layer.

[0007] Patent Document 4 describes a filter having a light-absorbing film. The light-absorbing film is formed from a cured product containing a liquid composition of a light-absorbing agent formed from an aryl phosphonic acid and copper ions. Patent Document 4 also describes the transmission spectrum of a filter with wavelengths from 300 nm to 2200 nm.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent No. 6339755

[0011] Patent Document 2: Japanese Patent No. 6232161

[0012] Patent Document 3: Japanese Patent No. 6281023

[0013] Patent Document 4: Japanese Patent No. 6639764 Summary of the Invention

[0014] The problem that the invention aims to solve

[0015] According to the technology described in Patent Documents 1-4, it is possible to absorb a portion of ultraviolet light and infrared light falling within the wavelength range of 700-1000 nm. On the other hand, from the viewpoint of improving the transmittance of the filter within a specific wavelength range having longer wavelengths, the technology described in Patent Documents 1-4 warrants further investigation. Therefore, the present invention provides a filter that blocks a portion of ultraviolet light and infrared light falling within the wavelength range of 700-1000 nm, and has high transmittance in the visible light region and within a specific wavelength range having longer wavelengths. Furthermore, a light-absorbing composition advantageous for manufacturing such a filter is provided.

[0016] Methods for solving problems

[0017] The present invention provides a filter having a first transmission spectrum at 25°C that satisfies the conditions (i), (ii), (iii) and (iv) below.

[0018] (i) The minimum transmittance in the wavelength range of 450 nm to 600 nm is 70% or more.

[0019] (ii) The maximum transmittance in the wavelength range of 300nm to 370nm is less than 5%.

[0020] (iii) The maximum transmittance in the wavelength range of 800nm ​​to 1000nm is less than 5%.

[0021] (iv) The minimum transmittance in the wavelength range of 1500nm to 1700nm is 60% or more.

[0022] In addition, the present invention provides an optical device comprising: A camera module that acquires image information from objects identified by visible light; A TOF sensor acquires distance measurement information from an object; and The aforementioned filter is positioned in front of the aforementioned camera module and the aforementioned TOF sensor.

[0023] In addition, the present invention provides a light-absorbing composition comprising: Copper complexes; At least one of a first alkoxy-containing compound having two alkoxy groups within its molecule and a hydrolysate thereof; and At least one of a second alkoxy-containing compound having 3 or 4 alkoxy groups in its molecule and a hydrolysate of the aforementioned second alkoxy-containing compound.

[0024] The effects of the invention

[0025] The aforementioned filter blocks a portion of ultraviolet light and light in the wavelength range of 700–1000 nm, and exhibits high transmittance in the visible light region and specific wavelength ranges with longer wavelengths. Furthermore, such a filter can be manufactured based on the aforementioned light-absorbing composition. Attached Figure Description

[0026] Figure 1 This is a cross-sectional view showing an example of the filter of the present invention.

[0027] Figure 2 This is a cross-sectional view showing another example of the filter of the present invention.

[0028] Figure 3 This is a block diagram illustrating an example of a device equipped with the filter of the present invention.

[0029] Figure 4 This is the transmission spectrum of the filter in Example 1.

[0030] Figure 5 This is the transmission spectrum of the filter in Example 2.

[0031] Figure 6 This is the transmission spectrum of the filter in Example 6.

[0032] Figure 7 This is the transmission spectrum of the filter in Example 7.

[0033] Figure 8 It is the transmission spectrum of a transparent glass substrate.

[0034] Figure 9 This is the transmission spectrum of the filter in Example 8.

[0035] Figure 10 This is the transmission spectrum of the filter in Example 11.

[0036] Figure 11 This is the transmission spectrum of the filter in Example 16.

[0037] Figure 12 This is the transmission spectrum of the filter in Example 19.

[0038] Figure 13 This is the transmission spectrum of the filter in Example 20. Detailed Implementation

[0039] The embodiments of the present invention will now be described with reference to the accompanying drawings. It should be noted that the following description relates to one example of the present invention, and the invention is not limited thereto.

[0040] Figure 1 The filter 1a shown has a first transmission spectrum at 25°C. The first transmission spectrum satisfies the conditions (i), (ii), (iii) and (iv) below.

[0041] (i) Minimum transmittance T in the wavelength range of 450 nm to 600 nm min 450-600 It is over 70%.

[0042] (ii) The maximum transmittance T in the wavelength range of 300 nm to 370 nm max 300-370 It is below 5%.

[0043] (iii) The maximum transmittance T in the wavelength range of 800 nm to 1000 nm max 800-1000 It is below 5%.

[0044] (iv) Minimum transmittance T in the wavelength range of 1500 nm to 1700 nm min 1500-1700 It is over 60%.

[0045] Here, "the minimum transmittance T in the wavelength range of X nm to Y nm" min X-Y "A% or higher" has the same meaning as "transmittance of A% or higher in the entire region of wavelength Xnm to Ynm". In addition, "the maximum transmittance T in the range of wavelength X'nm to Y'nm" is... max X’-Y’"Below B%" has the same meaning as "transmittance is below B% in the entire region of wavelength X'nm to Y'nm".

[0046] By ensuring that the first transmission spectrum of filter 1a satisfies condition (i), filter 1a exhibits high transmittance in the visible light region. Minimum value T min 450-600 Preferably, it is 75% or more, and more preferably 80% or more.

[0047] By ensuring that the first transmission spectrum of filter 1a satisfies condition (ii), a portion of ultraviolet light can be blocked. Maximum value T max 300-370 Preferably, it is 3% or less, more preferably 1% or less.

[0048] By ensuring that the first transmission spectrum of filter 1a satisfies condition (iii), light in the wavelength range of 800–1000 nm can be shielded. Maximum value T max 800-1000 Preferably, it is 3% or less, more preferably 1% or less.

[0049] By making the first transmission spectrum of filter 1a satisfy the condition (iv), filter 1a has high transmittance in a specific wavelength range with longer wavelengths, such as 1500 nm to 2000 nm.

[0050] Filter 1a exhibits high transmittance in the visible light region and a defined infrared region above 1500 nm. Therefore, for example, it can be used as a near-infrared cutoff filter in camera modules of portable terminals such as digital cameras or smartphones to block light of a portion of the infrared wavelengths that are outside the effective range of human visual sensitivity. In addition, filter 1a can also be applied to time-of-flight (TOF) ranging devices, such as LiDAR (Light Detection and Ranging) sensors, or their peripherals. In the use of TOF sensors in LiDAR and the like, light such as lasers with wavelengths belonging to the near-infrared region around 900 nm has sometimes been used. However, when using light with wavelengths around 900 nm, the light receiver, such as the sensor, may be affected by sunlight. Sunlight also contains a large amount of light with a wavelength of 900 nm, and due to background noise, ranging accuracy may deteriorate.

[0051] Therefore, research has focused on Time-of-Flight (TOF) methods using laser light at wavelengths around 1550 nm and on LiDAR using TOF methods. In the sunlight spectrum, the intensity and quantity of light at a wavelength of 1550 nm are lower than those at 900 nm. Therefore, to utilize light at wavelengths around 1550 nm, if the light receiver and its surrounding components can be designed in a manner corresponding to this wavelength region, then even during the day, noise caused by sunlight in LiDAR measurements can be reduced, thus potentially improving the signal-to-noise ratio (S / N) in the measurements.

[0052] It is envisioned that devices will emerge that integrate a camera module (for capturing images formed by light within the visible light region that is perceptible to humans) and a time-of-flight (TOF) ranging device, such as LiDAR, or devices that incorporate a portion of the TOF ranging function into the aforementioned camera module. For example, it is envisioned that a device can acquire images such as moving or still images captured by the aforementioned camera module, and also acquire images containing high-precision distance information obtained by a TOF ranging device such as LiDAR. Furthermore, it is envisioned that a device can acquire images such as moving or still images containing detailed distance information. In such a device, if filter 1a is used, light of wavelengths corresponding to the range of human visual sensitivity required to form an image can be transmitted, and light with wavelengths around 1550 nm, suitable for ranging devices, or light with longer wavelengths up to 2000 nm, can be transmitted. Moreover, it can block ultraviolet light and light with wavelengths of 700 nm to 1000 nm or 700 nm to 1100 nm; filter 1a offers excellent convenience, simplicity, and optical characteristics.

[0053] Filter 1a, for example, absorbs and blocks a portion of the light. Therefore, from the viewpoint of suppressing the occurrence of light spots and ghosting, which are problems inside the camera module or rangefinder, filter 1a is advantageous.

[0054] The impact of intense light from lasers and LEDs with a wavelength of 1550nm on the human eye is less than that from a wavelength of 900nm. For example, according to the safety standards for laser products in IEC 60825, established by the International Electrotechnical Commission, the maximum permissible exposure (MPE) at a wavelength of 900nm is 1 × 10⁻⁶ for a pulse width of 1 microsecond (μs). -6 J / cm 2 At a wavelength of 1550nm, it is 1J / cm. 2Human safety in the face of lasers is absolutely essential. From the perspective of expanding the scope of measurement, using light with a wavelength of approximately 1550 nm reduces the difficulty of ensuring safety, which is advantageous. In Time-of-Flight (TOF) ranging devices, such as LiDAR, distance is measured based on the time of flight of the light emitted from the object being measured. When a person holds the TOF ranging device, the reflected light from the object being measured returns to that person. In this case, if the TOF ranging device includes a light emitter that emits light with a wavelength of approximately 1550 nm, placing the TOF ranging device close to or at a height close to a person's eyes, face, or upper body is considered beneficial for the use of filter 1a due to safety considerations.

[0055] In the first transmission spectrum of filter 1a, the minimum value T min 1500-1700 Preferably, it is 70% or more, and more preferably 75% or more.

[0056] In the first transmission spectrum of filter 1a, the transmittance at a wavelength of 1550 nm is, for example, 70% or more, preferably 80% or more, and more preferably 85% or more.

[0057] The first transmission spectrum of filter 1a also satisfies, for example, the condition described below (v). Therefore, the first spectrum readily matches human visual sensitivity within the wavelength range of 550 nm to 800 nm.

[0058] (v) The first cutoff wavelength λ exhibits 50% transmittance in the wavelength range of 550 nm to 800 nm. C1 It exists in the range of 600nm to 700nm.

[0059] First cutoff wavelength λ C1 It is preferably present in the range of 620nm to 680nm.

[0060] The first transmission spectrum of filter 1a also satisfies, for example, the condition described below (vi). Therefore, filter 1a readily exhibits high transmittance in a specified infrared region above 1500 nm.

[0061] (vi) A second cutoff wavelength λ exhibiting 50% transmittance in the wavelength range of 1000 nm to 1800 nm. C2 It exists in the range of 1150nm to 1500nm.

[0062] Second cutoff wavelength λ C2 It is preferably present in the range of 1200nm to 1430nm.

[0063] Furthermore, in the first transmission spectrum of filter 1a, the second cutoff wavelength λ C2 With the first cutoff wavelength λ C1 The absolute value of the difference |λ C2 -λ C1 The value of | is, for example, 600 nm or more, preferably 650 nm or more, and more preferably 700 nm or more. Furthermore, |λ C2 -λ C1 The value of | is, for example, below 800nm, preferably below 780nm, and more preferably below 760nm.

[0064] The first transmission spectrum of filter 1a also satisfies, for example, the condition described below (vii). Therefore, the first spectrum readily matches human visual sensitivity in the wavelength range of 350 nm to 450 nm.

[0065] (vii) The third cutoff wavelength λ exhibits 50% transmittance in the wavelength range of 350 nm to 450 nm. C3 It exists in the range of 360nm to 430nm.

[0066] Furthermore, in the first transmission spectrum of filter 1a, the first cutoff wavelength λ C1 With the third cutoff wavelength λ C3 The absolute value of the difference |λ C1 -λ C3 The value of | is, for example, 200 nm or more, preferably 210 nm or more, and more preferably 220 nm or more. Furthermore, |λ C1 -λ C3 The value of | is, for example, below 270nm, preferably below 260nm, and more preferably below 250nm.

[0067] The first transmission spectrum of filter 1a also satisfies, for example, the condition described below (viii). Therefore, filter 1a is able to block a portion of infrared radiation with wavelengths from 1000 nm to 1100 nm.

[0068] (viii) The maximum transmittance T in the wavelength range of 1000nm to 1100nm max 1000-1100 It is below 10%.

[0069] Maximum value T max 1000-1100 Preferably, it is below 5%.

[0070] The first transmission spectrum of filter 1a also satisfies, for example, the condition described below (ix). Thus, filter 1a can be used, for example, in a device that uses light in the wavelength range of 1700 nm to 1900 nm for distance measurement.

[0071] (ix) Minimum transmittance T in the wavelength range of 1700 nm to 1900 nm min 1700-1900 It is over 60%.

[0072] Minimum value T min 1700-1900 Preferably, it is 65% or more, and more preferably 70% or more.

[0073] The first transmission spectrum of filter 1a also satisfies, for example, the condition described below (x). Thus, filter 1a can be used, for example, in a device that uses light in the wavelength range of 1900 nm to 2200 nm for distance measurement.

[0074] (x) Minimum transmittance T in the wavelength range of 1900nm to 2200nm min 1900-2200 It is over 60%.

[0075] Minimum value T min 1900-2200 Preferably, it is 65% or more, and more preferably 70% or more.

[0076] like Figure 1 As shown, the filter 1a includes, for example, a light-absorbing layer 10. The light-absorbing layer 10 contains a light-absorbing agent. The thickness of the light-absorbing layer 10 is not limited to a specific value. The light-absorbing layer 10 has, for example, a thickness of 100 μm to 400 μm. This makes it easy to reduce the height of the device equipped with the filter 1a. The thickness of the light-absorbing layer 10 is preferably 120 μm to 350 μm, more preferably 140 μm to 300 μm.

[0077] Filter 1a, for example, has a second transmission spectrum at 70°C, which has a fourth cutoff wavelength λ that exhibits 50% transmittance in the wavelength range of 550 nm to 800 nm. C4 The fourth cutoff wavelength λ C4 With the first cutoff wavelength λ C1 The absolute value of the difference |λ C4 -λ C1 | It is not limited to a specific value, for example, below 15nm. In this case, even if the ambient temperature of the filter 1a changes, the cutoff wavelength, which serves as the boundary between the transmission frequency band and the shielding frequency band, is not easily changed in the wavelength range of 550nm to 800nm.

[0078] Absolute value |λ C4 -λ C1 | Preferably, it is 10nm or less, more preferably 8nm or less, and even more preferably 5nm or less.

[0079] Filter 1a, for example, has a second transmission spectrum at 70°C, which has a fifth cutoff wavelength λ that exhibits 50% transmittance in the wavelength range of 1000 nm to 1800 nm. C5 The fifth cutoff wavelength λ C5 With the second cutoff wavelength λ C2 The absolute value of the difference |λ C5 -λ C2 | It is not limited to a specific value, for example, below 30nm. In this case, even if the ambient temperature of the filter 1a changes, the cutoff wavelength, which serves as the boundary between the transmission frequency band and the shielding frequency band, is not easily changed in the wavelength range of 1000nm to 1800nm.

[0080] Absolute value |λ C5 -λ C2 | Preferably below 20nm.

[0081] Filter 1a, for example, has a second transmission spectrum at 70°C, which has a sixth cutoff wavelength λ that exhibits 50% transmittance in the wavelength range of 350 nm to 450 nm. C6 The sixth cutoff wavelength λ C6 With the third cutoff wavelength λ C3 The absolute value of the difference |λ C6 -λ C3 | It is not limited to a specific value, for example, below 15nm. In this case, even if the ambient temperature of the filter 1a changes, the cutoff wavelength, which serves as the boundary between the transmission frequency band and the shielding frequency band, is not easily changed in the wavelength range of 350nm to 450nm.

[0082] Absolute value |λ C6 -λ C3 | Preferably, it is below 10nm, more preferably below 8nm.

[0083] In the first transmission spectrum of filter 1a, the average transmittance in the wavelength range of 1530 nm to 1570 nm is, for example, 70% or more, preferably 75% or more, and more preferably 80% or more. The filter exhibits high transmittance for light in the visible light region and high transmittance for light with a wavelength of approximately 1550 nm, which is advantageous for obtaining images containing distance information (obtained by a TOF-based ranging function).

[0084] In the first transmission spectrum of filter 1a, the ratio Tr(1) of the average transmittance in the wavelength range of 1530 nm to 1570 nm to the average transmittance in the wavelength range of 450 nm to 600 nm is, for example, 0.8 or more, preferably 0.85 or more. The ratio Tr(1) is, for example, 1.2 or less, preferably 1.1 or less.

[0085] In the first transmission spectrum of filter 1a, the average transmittance in the wavelength range of 1800 nm to 2100 nm is, for example, 80% or more, preferably 82% or more, and more preferably 85% or more. It can be considered that the increased transmittance of filter 1a in this wavelength range is due to a low content of functional groups or compounds having such functional groups in the light-absorbing layer 10 that absorb light in the wavelength range of 1800 nm to 2100 nm.

[0086] Filter 1a, for example, has the following characteristics: compared to the filter described in Patent Document 4, it exhibits less absorption and higher transmittance within a specific wavelength range. The first transmission spectrum of filter 1a may, for example, have minimum values ​​(absorption peaks) in the wavelength ranges of 1600 nm to 1800 nm and 2100 nm to 2200 nm. In this case, the minimum transmittance of the first transmission spectrum of filter 1a in the wavelength range of 1600 nm to 1800 nm is, for example, 70% or more, preferably 75% or more. The minimum transmittance of the first transmission spectrum of filter 1a in the wavelength range of 2100 nm to 2200 nm is, for example, 70% or more, preferably 75% or more.

[0087] In the first transmission spectrum of filter 1a, the ratio Tr(2) of the minimum transmittance in the wavelength range of 1600 nm to 1800 nm to the average transmittance in the wavelength range of 1800 nm to 2100 nm is, for example, 0.8 or more, preferably 0.85 or more. In addition, the ratio Tr(2) is, for example, 1.1 or less, preferably 1.0 or less.

[0088] In the first transmission spectrum of filter 1a, the ratio Tr(3) of the minimum transmittance in the wavelength range of 2100 nm to 2200 nm to the average transmittance in the wavelength range of 1800 nm to 2100 nm is, for example, 0.8 or more, preferably 0.85 or more. In addition, Tr(3) is, for example, 1.1 or less, preferably 1.0 or less.

[0089] The material constituting the light-absorbing layer 10 in the filter 1a is not limited to a specific material, provided that the first transmission spectrum of the filter 1a satisfies the conditions (i), (ii), (iii), and (iv) above. The light-absorbing layer 10 can be formed, for example, by curing a prescribed light-absorbing composition. In this case, the light-absorbing composition contains, for example, at least one of a copper complex, a first alkoxy-containing compound, and a hydrolysate of the first alkoxy-containing compound, and at least one of a second alkoxy-containing compound and a hydrolysate of the second alkoxy-containing compound. The first alkoxy-containing compound is a compound having two alkoxy groups within its molecule. The first alkoxy-containing compound is, for example, a compound capable of hydrolytic condensation. The second alkoxy-containing compound is a compound having three or four alkoxy groups within its molecule. The second alkoxy-containing compound is, for example, a compound capable of hydrolytic condensation. By curing such a light-absorbing composition, a filter satisfying the conditions (i), (ii), (iii), and (iv) above can be manufactured. The rationale for being able to fabricate a filter satisfying the conditions (i), (ii), (iii), and (iv) above by using such a light-absorbing composition is still uncertain. It is considered that by adding a first alkoxy-containing compound and adjusting its amount, the number of functional groups or groups of functional groups bonded to the surrounding three dimensions decreases, and the polymer composition in the layer becomes more sparse during and after the curing process. Therefore, it is considered that the amount of molecules with functional groups that may absorb in the infrared region is reduced from the layer due to evaporation or sublimation. It is considered that because these molecules or some functional groups absorb light with wavelengths of 1500 nm to 2000 nm, the filter has high transmittance in this wavelength range.

[0090] The transmission spectrum of the cured light-absorbing composition satisfies, for example, the conditions (i), (ii), (iii), and (iv) described above. The transmission spectrum of the cured light-absorbing composition may also satisfy at least one of the other conditions described above satisfied by the first transmission spectrum of filter 1a. In this case, the thickness of the cured light-absorbing composition is, for example, 100 μm to 400 μm.

[0091] The copper complex contains, for example, phosphonic acid and copper. The copper complex can be, for example, at least one selected from the group consisting of compounds containing phosphonic acid with an aryl group and copper, and compounds containing phosphonic acid with an alkyl group and copper. The copper complex can also contain both of these compounds. By including phosphonic acid and copper in the copper complex, the transmittance in the visible light region containing wavelengths of 450 nm to 650 nm can be increased using a filter, while absorbing a portion of ultraviolet light with wavelengths shorter than the visible light region and light with wavelengths exceeding 700 nm. Therefore, the transmission spectrum of the filter 1a can be easily matched to human visual sensitivity. The copper complex is, for example, encapsulated in a transparent material such as resin within the light-absorbing layer 10.

[0092] When the copper complex is a compound containing an aryl phosphonic acid and a copper component, it readily absorbs light primarily in the wavelength range of 300 nm to 400 nm and 800 nm to 1000 nm. Conversely, when the copper complex is a compound containing an alkyl phosphonic acid and a copper component, it readily absorbs light primarily in the wavelength range of 300 nm to 360 nm and 800 nm to 1100 nm.

[0093] In the light-absorbing composition, by adjusting the ratio of the content of the compound containing aryl phosphonic acid and copper to the content of the compound containing alkyl phosphonic acid and copper to a predetermined range, the transmittance of light in the wavelength range of 1500 nm to 1700 nm is easily improved in the filter 1a. Furthermore, by adjusting the ratio of the amount of aryl phosphonic acid added to the amount of alkyl phosphonic acid added in the light-absorbing composition to a predetermined range, the transmittance of light in the wavelength range of 1500 nm to 1700 nm is easily improved in the filter 1a.

[0094] Phosphonic acids containing an aryl group are not limited to specific phosphonic acids, such as phenylphosphonic acid, nitrophenylphosphonic acid, hydroxyphenylphosphonic acid, bromophenylphosphonic acid, dibromophenylphosphonic acid, fluorophenylphosphonic acid, difluorophenylphosphonic acid, chlorophenylphosphonic acid, dichlorophenylphosphonic acid, iodophenylphosphonic acid, diiodophenylphosphonic acid, benzylphosphonic acid, bromobenzylphosphonic acid, dibromobenzylphosphonic acid, fluorobenzylphosphonic acid, difluorobenzylphosphonic acid, chlorobenzylphosphonic acid, dichlorobenzylphosphonic acid, iodobenzylphosphonic acid, or diiodobenzylphosphonic acid.

[0095] Phosphonic acids having alkyl groups are not limited to specific phosphonic acids, but include, for example, phosphonic acids having alkyl groups having 1 to 8 carbon atoms.

[0096] In the light-absorbing composition, the content of aryl phosphonic acid (Cf) and the content of alkyl phosphonic acid (Cs) are not limited to a specific relationship. In the light-absorbing composition, the Cf:Cs ratio, on a mass basis, is, for example, 40:60 to 100:0, preferably 50:50 to 100:0. Therefore, filters made using the light-absorbing composition readily possess the desired transmission characteristics.

[0097] In the light-absorbing composition, the ratio of content Cfc to content Ctc is not limited to a specific value. Content Ctc is the content of the alkoxy-containing compound and its hydrolysate converted into a fully hydrolyzed condensate. Content Cfc is the content of the first alkoxy-containing compound and its hydrolysate converted into a fully hydrolyzed condensate. The ratio of content Cfc to content Ctc, on a mass basis, is, for example, 0.01 to 0.6. As described above, it can be considered that by reducing the number of functional groups or groups of functional groups bonded to the surrounding three dimensions through the first alkoxy-containing compound, the polymer composition in the layer tends to become more sparse during and after curing. A more sparse structure is considered to help remove solvents or byproducts. On the other hand, by making the ratio of content Cfc to content Ctc 0.6 or less, network formation in the layer is easily promoted. As a result, a non-sticky light-absorbing layer can be formed, and the light-absorbing composition can be easily cured in the desired state. In addition, the mechanical strength of the cured light-absorbing composition can easily withstand physical or chemical treatment in the next process.

[0098] The ratio of Cfc content to Ctc content, measured by mass, is preferably 0.02 to 0.5, more preferably 0.03 to 0.4.

[0099] The light-absorbing composition may or may not contain a curable resin. In the light-absorbing composition, the ratio of the solid content (Crs) of the curable resin to the content (Ctc) of the compound having an alkoxy group and its hydrolysate converted into a fully hydrolyzed condensate is not limited to a specific value. The ratio of the solid content (Crs) to the content (Ctc), on a mass basis, is, for example, 0 to 2. The curable resin can improve the density and mechanical strength of the light-absorbing layer 10. On the other hand, by making the ratio of the solid content (Crs) to the content (Ctc) 2 or less, the effect of the first alkoxy-containing compound on making the polymer structure in the layer relatively sparse can be suppressed by the curable resin.

[0100] The ratio of solid component Crs to content Ctc, on a mass basis, is preferably 0 to 1.5, more preferably 0 to 1.3, and even more preferably 0 to 1.28. This allows for a relatively low content of curable resin in the light-absorbing composition.

[0101] In the light-absorbing composition, the ratio of content Cfc to Ctr is not limited to a specific value. Ctr is the sum of the content Ctc of the alkoxy-containing compound and its hydrolysate converted into a fully hydrolyzed condensate, and the solid content Crs of the curable resin. Content Cfc is the content of the first alkoxy-containing compound and its hydrolysate converted into a fully hydrolyzed condensate. The ratio of content Cfc to Ctr, on a mass basis, is, for example, 0.01 to 0.4. Therefore, it can be considered that the polymer composition in the layer tends to become relatively sparse during and after curing. On the other hand, by setting the ratio of content Cfc to Ctr to 0.4 or less, a non-sticky light-absorbing layer can be formed, and the light-absorbing composition can be cured in the desired state. The mechanical strength of the cured light-absorbing composition can withstand physical or chemical treatment in the next process. The ratio of Cfc to Ctr, measured by mass, is preferably 0.02 to 0.35, more preferably 0.02 to 0.3, and even more preferably 0.04 to 0.26.

[0102] In the light-absorbing composition, the first alkoxy-containing compound and the second alkoxy-containing compound can each be, for example, a silanolate (alkoxysilane) or an alkoxide of metals such as Ti and Al. Aloxides with two alkoxy groups are called difunctional alkoxides, alkoxides with three alkoxy groups are called trifunctional alkoxides, and alkoxides with four alkoxy groups are called tetrafunctional alkoxides. Alkoxysilanes with two to four alkoxy groups are respectively called 2- to 4-functional alkoxysilanes.

[0103] Alkoxysilanes hydrolyze and polymerize in the presence of water and acid catalysts to form polymers or inorganic compounds. Tetrafunctional alkoxysilanes hydrolyze and polymerize to form solid compounds as shown in SiO2. Trifunctional alkoxysilanes hydrolyze and polymerize to form R-SiO2. 1.5 The solid compounds shown are as follows. It should be noted that in this specification, "R-" refers to an organic component. These compounds can form a three-dimensional network. The light-absorbing composition may contain at least one compound selected from the group consisting of trifunctional alkoxysilanes, hydrolysates of trifunctional alkoxysilanes, tetrafunctional alkoxysilanes, and hydrolysates of tetrafunctional alkoxysilanes. Each molecule of a difunctional alkoxysilane has only two reactive functional groups. It can be considered that when the light-absorbing composition contains difunctional alkoxysilanes, the number of functional groups or groups of functional groups bonded to the surrounding three dimensions is reduced, and the polymer composition of the cured layer and the cured layer tends to become more sparse. Therefore, it can be considered that during the curing process of the light-absorbing composition, acetic acid or alcohol generated by the solvent or reaction can be easily and efficiently expelled to the outside. As a result, it can be considered that a portion of the molecules with functional groups capable of absorbing light in a specified wavelength range in the infrared region are reduced from the layer due to evaporation and sublimation, thereby suppressing the absorption of light in that wavelength range.

[0104] Tetrafunctional alkoxysilanes are not limited to specific alkoxysilanes, such as tetramethoxysilane or tetraethoxysilane. Trifunctional alkoxysilanes are not limited to specific alkoxysilanes. Examples of trifunctional alkoxysilanes include methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropyltriethoxysilane, n-propyltriethoxysilane, n-propyltrimethoxysilane, hexyltriethoxysilane, hexyltrimethoxysilane, trifluoropropyltriethoxysilane, trifluoropropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, or 3-isocyanatepropyltrimethoxysilane. Difunctional alkoxysilanes are not limited to specific alkoxysilanes. Difunctional alkoxysilanes include, for example, dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, or 3-epoxypropoxypropylmethyldiethoxysilane.

[0105] In the light-absorbing composition, the curable resin may encapsulate a copper complex. The curable resin may encapsulate an alkoxylated compound, a hydrolysate of that compound, or a polymer of that compound. When a filter is fabricated by curing the light-absorbing composition, the following advantages are available: due to the presence of the curable resin, the density of the layer or film formed by curing the light-absorbing composition is increased, making it easier to improve the rigidity of the layer or film. On the other hand, by adjusting the content of the curable resin in the light-absorbing composition, the effect of the first alkoxylated compound in making the layer structure moderately sparse is difficult to reduce.

[0106] The curing resin is not limited to a specific resin. For example, the curing resin is at least one selected from the group consisting of epoxy resin, polyurethane resin, acrylic resin, polyolefin resin and silicone resin.

[0107] The light-absorbing composition may also contain phosphate esters. In the light-absorbing layer formed using the light-absorbing composition, compared to phosphate esters, compounds with alkoxy groups or hydrolysates of such compounds can impart high moisture resistance to the light-absorbing layer while appropriately dispersing the copper complex. Therefore, by including compounds with alkoxy groups or hydrolysates of such compounds in the light-absorbing composition, the amount of phosphate ester used can be reduced. The light-absorbing composition may also not contain phosphate esters.

[0108] Phosphate esters, for example, are phosphate esters containing polyoxyalkyl groups. Phosphate esters containing polyoxyalkyl groups are not limited to specific phosphate esters. Examples of phosphate esters containing polyoxyalkyl groups include Plysurf A208N: polyoxyethylene alkyl (C12, C13) ether phosphate, Plysurf A208F: polyoxyethylene alkyl (C8) ether phosphate, Plysurf A208B: polyoxyethylene lauryl ether phosphate, Plysurf A219B: polyoxyethylene lauryl ether phosphate, Plysurf AL: polyoxyethylene styrene phenyl ether phosphate, Plysurf A212C: polyoxyethylene tridecyl ether phosphate, or Plysurf A215C: polyoxyethylene tridecyl ether phosphate. These are all products manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd. Alternatively, the phosphate esters may be, for example, NIKKOL DDP-2: polyoxyethylene alkyl ether phosphate, NIKKOL DDP-4: polyoxyethylene alkyl ether phosphate, or NIKKOL DDP-6: polyoxyethylene alkyl ether phosphate. These are all products manufactured by Nikkol Chemicals.

[0109] like Figure 1 As shown, the filter 1a also includes a transparent substrate 20. The transparent substrate 20 has a pair of parallel main surfaces. In the filter 1a, a light-absorbing layer 10 is disposed on one main surface of the transparent substrate 20. The filter 1a may also be modified to have the light-absorbing layer 10 disposed on both main surfaces of the transparent substrate 20. The light-absorbing layer 10 can be formed, for example, by coating the aforementioned light-absorbing composition onto one or both main surfaces of the transparent substrate 20 and then curing it. It should be noted that the light-absorbing layer 10 can also be in contact with the main surface of the transparent substrate 20. On the other hand, as long as the first transmission spectrum of the filter 1a satisfies the conditions (i), (ii), (iii), and (iv) above, other functional layers may also be formed between the light-absorbing layer 10 and the main surface of the transparent substrate 20. Other functional layers are not limited to specific layers, such as layers that improve the adhesion between the light-absorbing layer 10 and the transparent substrate 20, or layers other than those obtained by curing the aforementioned light-absorbing composition. As long as the first transmission spectrum of the filter 1a satisfies the conditions (i), (ii), (iii), and (iv) above, the transparency of the transparent substrate 20 is not limited to a specific level. For example, as the transparent substrate 20, a substrate exhibiting a transmittance of 75% or more at wavelengths of 400 nm to 700 nm with a thickness of 0.2 mm can be used. Alternatively, the transparent substrate 20 can also be a substrate having a transmission spectrum exhibiting a transmittance of 75% or more at wavelengths of 1400 nm to 2200 nm.

[0110] The transparent substrate 20 is not limited to a specific substrate. The transparent substrate 20 can be a transparent glass substrate containing glass or a transparent resin substrate containing resin. Transparent glass substrates have high transparency and a remarkably smooth main surface, and are very inexpensive. Furthermore, due to their high hardness and high Young's modulus, transparent glass substrates can withstand manufacturing processes or distribution even with small thicknesses. Transparent resin substrates have high transparency, are lightweight, and are suitable for various production processes. When the transparent substrate 20 is a transparent resin substrate, substrates of various shapes can be supplied inexpensively, for example. The material of the transparent resin substrate is not limited to a specific material. The material of the transparent resin substrate can be, for example, epoxy resin, polyurethane resin, acrylic resin, polyethylene resin, polyethylene terephthalate resin, polypropylene resin, polyolefin resin, polyamide resin, polyimide resin, polyvinyl chloride resin, polystyrene resin, or silicone resin.

[0111] The filter 1a can be modified to have a light-absorbing layer disposed on the surface of an optical element such as a lens, diffraction grating, or polarizing element. For example, a filter can be provided in which the aforementioned light-absorbing composition is coated onto the surface of an optical element such as a lens and cured thereon, thereby having both an optical element and a light-absorbing layer. For example, if the filter is configured to include at least one lens in a lens system included in a camera module, it is not necessary to fabricate and configure a separate filter to allow light with the desired transmission spectrum to be incident on the imaging element. Thus, for example, by forming the light-absorbing layer 10 on at least one surface of a functional optical element, a filter that combines the inherent function of the optical element with the function of light absorption can be provided. The optical element is not limited to the elements mentioned above. The material included in the optical element is not limited to a specific material, and may include, for example, the material used as the material of the transparent substrate 20.

[0112] Filter 1a can also be changed to Figure 2The filter 1b shown is a film-like filter having a light-absorbing layer 10. The filter 1b is obtained, for example, by coating the light-absorbing composition onto the main surface of a substrate having a smooth main surface, curing it to form the light-absorbing layer 10, and then detaching the light-absorbing layer 10 from the substrate. The smooth main surface of the substrate is configured such that the filter 1b satisfies the conditions (i), (ii), (iii), and (iv) above. The transparent substrate 20 described above, as well as a metal substrate or a ceramic substrate, can be used as the substrate for manufacturing the filter 1b. The filter 1b is a film-like filter, configured as a substrate-free filter. Therefore, the filter 1b is suitable for thinning, and the manufacturing cost of the filter 1b is easily reduced. The filter 1b can also be obtained by forming the light-absorbing layer 10 on the substrate and then peeling the light-absorbing layer 10 off the substrate. Before coating the light-absorbing composition onto the substrate, the smooth main surface of the substrate can also be coated with a fluoropolymer. Therefore, the light-absorbing layer 10 can be easily peeled off from the substrate.

[0113] Alternatively, a light-absorbing layer 10 can be formed by coating the aforementioned light-absorbing composition onto a substrate containing a curved or lattice-like structure or an uneven surface, and then curing it. The light-absorbing layer 10 can then be detached from the substrate to obtain a filter. In this case, the light-absorbing layer 10 is formed along the surface of the substrate, and therefore has a shape corresponding to the surface of the substrate. Thus, it is possible to manufacture a filter that corresponds to the characteristics of the surface of the substrate.

[0114] Filter 1a or 1b can be modified to include, in addition to the light-absorbing layer 10, an anti-reflective film or a light-reducing film that reduces the reflectivity of visible light or light with wavelengths above 1500 nm. This makes it easier to increase the amount of light of that wavelength reaching the imaging element. By also including an anti-reflective film or a light-reducing film in the filter, for example, the reflectivity of light reflected from the filter can be made less than 5%.

[0115] The anti-reflective film or anti-reflective coating is formed on at least one surface of the light-absorbing layer 10, for example, by one or more materials in a manner having one or more layers. The materials constituting the anti-reflective film or anti-reflective coating are not limited to specific materials. For example, the anti-reflective film or anti-reflective coating may be made of SiO2 or SiO2. 1.5The antireflective film or anti-reflective coating is formed using methods such as sol-gel, and can also be a film in which hollow microparticles or low-refractive-index material microparticles are dispersed in its main components. The antireflective film or anti-reflective coating contains TiO2, Ta2O3, SiO2, Nb2O5, ZnS, MgF, or mixtures thereof, and can be formed by methods such as vapor deposition, sputtering, or ion plating. The vapor deposition method can also be ion beam assisted vapor deposition. The antireflective film or anti-reflective coating can be a single-layer film containing the above-mentioned materials, or it can be a multilayer film formed by alternating layers of different materials. Furthermore, the antireflective film or anti-reflective coating can be formed in contact with the light-absorbing layer 10, or it can be formed in contact with other functional layers formed in contact with the light-absorbing layer 10.

[0116] In addition to the light-absorbing layer 10, the filters 1a or 1b may also include a film with high reflectivity for light in the wavelength range to be shielded, i.e., a so-called light-reflecting film. In this case, the filter can also satisfy the conditions related to the aforementioned transmission spectrum through the cooperation of the light-absorbing layer 10 and the light-reflecting film. By effectively adjusting the spectrum of the light-reflecting film, for example, the thickness of the light-absorbing layer 10 can be reduced. The light-reflecting film can be formed on at least one surface of the light-absorbing layer 10, for example, from one or more materials in a manner having more than one layer. The material constituting the light-reflecting film is not limited to a specific material. The light-reflecting film can be made of SiO2 or SiO2. 1.5 The light-reflecting film is formed using methods such as sol-gel, with the main component being a film, or a film in which hollow microparticles or low-refractive-index material microparticles are dispersed in the main component. The light-reflecting film contains TiO2, Ta2O3, SiO2, Nb2O5, ZnS, MgF, or mixtures thereof, and can be formed by methods such as vapor deposition, sputtering, or ion plating. The vapor deposition method can also be ion beam assisted vapor deposition. The light-reflecting film can be a single-layer film containing the above-mentioned materials, or a multilayer film formed by alternating layers of different materials. The light-reflecting film can be formed in contact with the light-absorbing layer 10, in contact with other functional layers formed in contact with the light-absorbing layer 10, or in contact with at least one main surface of the transparent substrate 20.

[0117] The filter of the present invention is not limited to the above-described manner. As long as there is no technical contradiction, the above-described features related to the filter can also be appropriately combined.

[0118] Using filter 1a, for example, it can provide Figure 3 The device 50 shown. In addition to the filter 1a, the device 50 also includes a TOF sensor unit 30 and a camera module unit 40. The camera module unit 40 is an element for forming an image by recognizing light in the visible light region or the infrared region. The camera module unit 40 acquires image information, for example, light recognized from the visible light or infrared region. It should be noted that... Figure 3Only the minimum components or functions required for the description are described. Device 50 may also have other components.

[0119] The TOF sensor unit 30 acquires, for example, distance information to an object. The TOF sensor unit 30 includes an illuminator 31, a light receiver 33, and a control unit 35. The illuminator 31 emits light as illumination light LI with a wavelength of approximately 1550 nm or within the wavelength range of 1500 nm to 2200 nm, illuminating the object G. The light receiver 33 receives reflected light LR from the object G. The wavelength of the reflected light LR can be within the wavelength range of 1500 nm to 2200 nm. The control unit 35 controls the illuminator 31 and the light receiver 33. A distance information image Id, which is the output image from the TOF sensor unit 30, can be obtained. In the distance information image Id, for example, the distance to the object G is represented by differences in intensity or color.

[0120] Illuminator 31 includes, for example, a light-emitting element and an optical element. The light-emitting element is an element such as a laser or LED that emits light with wavelengths within the aforementioned range. The optical element is an element used to illuminate the object G being measured with light from the light-emitting element. The optical element included in illuminator 31 may include multiple lenses, prisms, or other refractive or deflector elements, or diffuser elements for diffusing light. Figure 3 The illustrations of the light-emitting element and optical element in the illuminator 31 are omitted.

[0121] The light receiver 33 includes, for example, an optical element and a light receiving element. The optical element is used to receive reflected light LR from the object being measured G. The optical element included in the light receiver 33 may include multiple lenses, prisms, or other refractive or deflector elements, or diffuser elements for scattering light. The optical element focuses the reflected light LR from the object being measured G onto the light receiving element. The light receiving element can be a CCD or CMOS image sensor, or an avalanche photodiode (APD). Figure 3 The illustrations of the optical elements and optical receiving elements in the optical receiver 33 are omitted.

[0122] The camera module 40 acquires an image of an object illuminated by a reference light. The reference light can be sunlight or light in the infrared region illuminated by an illuminator located near the camera module. The camera module 40 includes, for example, a camera module 43 and a control unit 45 for controlling the camera module 43. The camera module 43 includes, for example, an optical element and a light-receiving element. The optical element is an element for receiving light from the object. The control unit 45 controls, for example, the optical element and the light-receiving element. The output image from the camera module 40 is, for example,... Figure 3The image Iu shows a typical image of the object. The typical image Iu can be an image containing the shape and color of the object that can be recognized by visible light. When infrared light is used as a reference light, the device 50 can function as a night vision camera. On the other hand, in this case, it is sometimes necessary to be aware that the wavelength region of the light used in the TOF sensor unit 30 overlaps with the wavelength region of the reference light, or that noise arises from this overlap.

[0123] The optical elements included in the camera module 43 may include multiple lenses, or refractors or deflectors such as prisms. These optical elements converge light from the object to a light-receiving element included in the camera module 43. The light-receiving element may be a CCD or CMOS image sensor. Figure 3 The diagrams of the optical elements and light receiving elements of the camera module 43 are omitted.

[0124] like Figure 3 As shown, filter 1a is disposed, for example, between the light receiver 33 and camera module 43 of the TOF sensor unit 30 and the object to be measured G. Filter 1a may also be disposed between the illuminator 31, light receiver 33, and camera module 43 of the TOF sensor unit 30 and the object to be measured G. In other words, filter 1a can be disposed in front of a device equipped with TOF sensor unit 30 and camera module 43. Filter 1a, for example, allows light of wavelengths in the visible light region and light with wavelengths around 1550 nm or in the range of 1500 nm to 2200 nm to pass through with high transmittance, and can block ultraviolet light and light in the range of 700 nm to 1100 nm. Therefore, filter 1a alone can allow only the wavelengths of light required to perform the functions of the TOF sensor unit 30 and camera module 40 to pass through.

[0125] Imagine an increase in devices that integrate both a TOF sensor and a camera module. For example, suppose both the TOF sensor and camera module are installed in smartphones and tablet-type information terminals. Because these devices are small and thin, it is possible to configure the TOF sensor and camera module close together. By using filter 1a, a simpler configuration can be achieved around the TOF sensor and camera module.

[0126] The device 50 may also include a glass cover (not shown) for protecting the device 50. This glass cover may also be positioned in front of the filter 1a, that is, closer to the object G being measured than the filter 1a. Using the glass cover, the filter 1a, the TOF sensor section 30, and the camera module section 40 can be protected from external impacts or temperature changes. It should be noted that, for example, the filter 1a can be fabricated by forming a light-absorbing layer 10 on a rigid transparent substrate 20, such as glass or sapphire. Since sapphire and the like have particularly high hardness, for example, by arranging the filter 1a with the main surface of the transparent substrate 20 where the light-absorbing layer 10 is formed facing the camera module, a filter 1a that also provides protection can be provided.

[0127] Example

[0128] The present invention will be described in more detail through embodiments. It should be noted that the present invention is not limited to the following embodiments.

[0129] <Example 1>

[0130] A copper acetate solution was obtained by mixing 4.500 g of copper acetate monohydrate and 240 g of tetrahydrofuran (THF) and stirring for 3 hours. Next, 1.646 g of Plysurf A208N (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), a phosphate ester compound, was added to the obtained copper acetate solution and stirred for 30 minutes to obtain solution A1. 40 g of THF was added to 0.706 g of phenylphosphonic acid and stirred for 30 minutes to obtain solution B1α. 40 g of THF was added to 4.230 g of 4-bromophenylphosphonic acid and stirred for 30 minutes to obtain solution B1β. Next, solutions B1α and B1β were mixed and stirred for 1 minute. Then, 8.664 g of methyltriethoxysilane (MTES) (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-13) and 2.840 g of tetraethoxysilane (TEOS) (premium grade manufactured by Kishida Chemical Co., Ltd.) were added to the mixture, and the mixture was stirred for another minute to obtain solution B1. While stirring solution A1, solution B1 was added to solution A1, and the mixture was stirred at room temperature for 1 minute. Next, 100 g of toluene was added to the solution, and the mixture was stirred at room temperature for 1 minute to obtain solution C1. Solution C1 was transferred to a flask and desolventized using a rotary evaporator (manufactured by Tokyo Rikagi K.K. Co., Ltd., model: OSB-2100) while heated in an oil bath. The oil bath temperature was set to 105°C. Finally, the desolventized solution D1 was removed from the flask. Thus, a D1 solution containing a light-absorbing compound (which includes phosphonic acid with an aryl group and copper components) is obtained.

[0131] 4.500 g of copper acetate monohydrate and 240 g of THF were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, 2.573 g of Plysurf A208N (a phosphate ester compound) was added to the obtained copper acetate solution, and the mixture was stirred for 30 minutes to obtain solution E1. Separately, 40 g of THF was added to 2.885 g of n-butylphosphonic acid and stirred for 30 minutes to obtain solution F1. While stirring solution E1, solution F1 was added to solution E1, and the mixture was stirred at room temperature for 1 minute. Then, 100 g of toluene was added to this solution, and the mixture was stirred at room temperature for 1 minute to obtain solution G1. Solution G1 was transferred to a flask and desolventized using a rotary evaporator while heated in an oil bath. The oil bath temperature was set to 105°C. Afterward, the desolventized solution H1 was removed from the flask. Thus, solution H1 containing a light-absorbing compound (which includes an aryl phosphonic acid and a copper component) was obtained.

[0132] Liquid D1 and liquid H1 were mixed in a mass ratio of Cf (containing aryl phosphonic acid) to Cs (containing alkyl phosphonic acid) of 71:29. Then, a curable resin (manufactured by Shin-Etsu Chemical Industry Co., Ltd., product name: KR-300), a catalyst (manufactured by Shin-Etsu Chemical Industry Co., Ltd., product name: CAT-AC), methyltriethoxysilane (MTES) (manufactured by Shin-Etsu Chemical Industry Co., Ltd., product name: KBE-13), tetraethoxysilane (TEOS) (premium grade, manufactured by Kishida Chemical Co., Ltd.), and dimethyldiethoxysilane (DMDES) (manufactured by Shin-Etsu Chemical Industry Co., Ltd., product name: KBE-22), were mixed in the amounts shown in Table 1. The mixture was stirred for 30 minutes to obtain the light-absorbing composition of Example 1. Table 2 shows the conversion of each alkoxysilane in the light-absorbing composition of Example 1 into the solid content of the fully hydrolyzed condensate and the solid content of the curable resin. In Table 1, the mixing amount (addition amount) of each raw material during mixing or preparation of the light-absorbing composition is also mainly shown in other examples and comparative examples.

[0133] A fluorinated substrate (active ingredient concentration: 0.1 g) was prepared by mixing 0.1 g of a surface antifouling coating agent (manufactured by Daikin Industries, product name: Optool DSX, active ingredient concentration: 20% by mass) and 19.9 g of a hydrofluoric ether solution (manufactured by 3M, product name: Novec 7100) and stirring for 5 minutes. This fluorinated substrate was then coated onto a main surface of a borosilicate glass substrate (manufactured by SCHOTT, product name: D263 Teco) with dimensions of 130 mm × 100 mm × 0.70 mm. The glass substrate was then left at room temperature for 24 hours to allow the fluorinated substrate coating to dry. Afterward, the glass surface was gently wiped with a lint-free cloth containing Novec 7100 to remove excess fluorinated substrate. This process completes the preparation of the fluorinated substrate.

[0134] A coating film of the light-absorbing composition of Example 1 was formed by applying it to an 80mm × 80mm area at the center of one main surface of a fluorinated substrate using a dispenser. After the resulting coating film was thoroughly dried at room temperature, it was placed in an oven and heated to 45°C for 6 hours while simultaneously removing solvents and byproducts. Then, the temperature was increased from 45°C to 85°C for 8 hours while further removing solvents and byproducts. Afterward, the coating film was peeled off from the fluorinated substrate, and the resulting film was placed at 85°C and 85% relative humidity for 24 hours for post-curing to complete the reaction. After the film had dried to a certain extent, it was peeled off from the substrate, further promoting the reaction and removing residual solvents and byproducts. The light-absorbing composition of Example 1 contains a specified amount of hydrolyzable alkoxysilane. The post-curing conditions were set to promote the hydrolysis and polymerization of the alkoxysilane and the bonding of the polymer. Thus, the filter of Example 1 was obtained.

[0135] <Examples 2-7>

[0136] Except for adjusting the amount of each raw material as shown in Table 1, the process was carried out in the same manner as in Example 1 to obtain the light-absorbing compositions of Examples 2 to 7. The light-absorbing compositions of Examples 2 to 7 were used instead of the light-absorbing composition of Example 1, and the process was carried out in the same manner as in Example 1 to obtain the filters of Examples 2 to 7.

[0137] <Example 8>

[0138] Dimethyldimethoxysilane (DMDMS) (manufactured by Shin-Etsu Chemical Industry Co., Ltd., product name: KBM-22) was used as the difunctional alkoxysilane. The amount of each raw material was adjusted as shown in Table 1. Otherwise, the procedure was the same as in Example 1 to obtain the light-absorbing composition of Example 8.

[0139] Using a dispenser, the light-absorbing composition of Example 8 was applied to an 80mm x 80mm area at the center of one main surface of a borosilicate glass (manufactured by SCHOTT, product name: D263 Teco) with dimensions of 130mm x 100mm x 0.70mm to form a coating film. After the resulting coating film was thoroughly dried at room temperature, it was placed in an oven and heated to 45°C for 6 hours while simultaneously removing solvents and byproducts. Then, the temperature was increased from 45°C to 85°C for 8 hours while further removing solvents and byproducts. Afterward, the coating film was post-cured for 24 hours at 85°C and 85% relative humidity to complete the reaction. Thus, the filter of Example 8, comprising a glass substrate as a transparent substrate and a light-absorbing layer, was obtained.

[0140] <Examples 9-21>

[0141] Except for adjusting the amount of each raw material as shown in Table 1, the process was carried out in the same manner as in Example 1 to obtain the light-absorbing compositions of Examples 9 to 21. The light-absorbing compositions of Examples 9 to 21 were used instead of the light-absorbing composition of Example 1, and the process was carried out in the same manner as in Example 1 to obtain the filters of Examples 9 to 21.

[0142] <Comparative Example 1>

[0143] Except for adjusting the amount of each raw material as shown in Table 1, the procedure was carried out in the same manner as in Example 1 to obtain the light-absorbing composition of Comparative Example 1. The light-absorbing composition of Comparative Example 1 was used instead of the light-absorbing composition of Example 1, and the procedure was carried out in the same manner as in Example 1 to obtain the filter of Comparative Example 1.

[0144] <Determination of Transmission Spectroscopy>

[0145] The transmission spectra of filters from Examples 1-15, Examples 17-21, and Comparative Example 1 were measured at an incident angle of 0° using a UV-Vis-NIR spectrophotometer (V-770, manufactured by Nippon Spectrophotometer Co., Ltd.). Unless otherwise specified, the ambient temperature around the filters was set to 25°C for all transmission spectrum measurements. The results of the transmission spectra measurements for filters from Examples 1, 2, 6, 7, 8, 11, 19, and 20 are shown below. Figure 4 , 5 In examples 6, 7, 9, 10, 12, and 13. Furthermore, some characteristics related to wavelength and transmittance derived from the transmission spectrum measurements of the filters based on each embodiment and the transmission spectrum measurements of the filter in Comparative Example 1 are shown in Tables 3 and 4. It should be noted that the transmission spectrum of the borosilicate glass substrate used as a transparent substrate in Example 8 was also measured individually at an incident angle of 0°. The results are shown in... Figure 8 .like Figure 8 As shown, the glass substrate has a transmittance of at least 90% in the wavelength range of 360nm to 2500nm.

[0146] The filter of Example 16 was installed inside a small thermostat manufactured by OPTQUEST, and the temperature inside the thermostat was adjusted to 25°C. Under these conditions, the transmission spectrum of the filter of Example 16 at a 0° incident angle was measured using a Hitachi U-4100 UV-Vis spectrophotometer. Similarly, the transmission spectrum of the filter of Example 16 at a 0° incident angle was measured with the temperature inside the thermostat adjusted to 70°C. The transmission spectra of Example 16 at each temperature are shown below. Figure 11 . Figure 11 In the diagram, the solid line represents the transmission spectrum at 25°C, and the dashed line represents the transmission spectrum at 70°C. Some characteristics related to wavelength and transmittance derived from the transmission spectrum measurements based on the filter of Example 16 are shown in Tables 3 and 4.

[0147] <Thickness Measurement>

[0148] The thickness of the filters in each embodiment and Comparative Example 1 was measured using a Keyence LK-H008 laser displacement meter. The results are shown in Table 3. It should be noted that the thickness of the filter in Example 8 does not take into account the thickness of the glass substrate.

[0149] As shown in Table 3, the filters of each embodiment satisfy the conditions (i), (ii), (iii), (iv), (v), (vi), (vii), (viii), (ix), and (x) described above. According to the filter of Example 8, it can be seen that even if the light-absorbing composition does not contain a curable resin, a desired filter can be obtained. On the other hand, the filter of Comparative Example 1 does not satisfy condition (ii).

[0150] In the filters of Example 21 and Comparative Example 1, the minimum transmittance in the wavelength range of 1500 nm to 1700 nm was lower than that of the filters of Examples 1 to 20. This suggests that in the light-absorbing composition, a mass ratio of Cf:Cs = 50:50 to 100:0 for the content of aryl phosphonic acid (Cf) and the content of alkyl phosphonic acid (Cs) is advantageous for improving the minimum transmittance in the wavelength range of 1500 nm to 1700 nm.

[0151] according to Figure 11As shown in Table 3, even when the temperature of the filter changes from 25°C to 70°C, the cutoff wavelengths of the transmission spectrum of the filter in Example 16 in the wavelength range of 550nm to 800nm, 1000nm to 1800nm, and 350nm to 450nm do not change significantly.

[0152] Table 1

[0153] Table 2

[0154] Table 3

[0155] Table 4

Claims

1. A filter comprising a cured form of a light-absorbing composition, said light-absorbing composition comprising a copper complex; At least one of a first alkoxy-containing compound having two alkoxy groups within its molecule and a hydrolysate thereof; and At least one of a second alkoxy-containing compound having 3 or 4 alkoxy groups in its molecule and a hydrolysate thereof; The filter has a first transmission spectrum at 25°C that satisfies the following conditions (i), (ii), (iii) and (iv): (i) The minimum transmittance in the wavelength range of 450 nm to 600 nm is 70% or more; (ii) The maximum transmittance in the wavelength range of 300 nm to 370 nm is less than 5%; (iii) The maximum transmittance in the wavelength range of 800 nm to 1000 nm is less than 5%; (iv) The minimum transmittance in the wavelength range of 1500nm to 1700nm is 60% or more.

2. The filter as claimed in claim 1, wherein, The first transmission spectrum also satisfies the following condition (v): (v) The first cutoff wavelength that exhibits 50% transmittance in the wavelength range of 550 nm to 800 nm exists in the wavelength range of 600 nm to 700 nm.

3. The filter as claimed in claim 1, wherein, The first transmission spectrum also satisfies the following condition (vi): (vi) A second cutoff wavelength exhibiting 50% transmittance in the wavelength range of 1000 nm to 1800 nm exists in the wavelength range of 1150 nm to 1500 nm.

4. The filter as claimed in claim 1, wherein, The first transmission spectrum also satisfies the following condition (vii): (vii) A third cutoff wavelength exhibiting 50% transmittance in the wavelength range of 350 nm to 450 nm exists in the range of 360 nm to 430 nm.

5. The filter as claimed in claim 1, wherein, In the first transmission spectrum, the absolute value of the difference between the first cutoff wavelength, which exhibits 50% transmittance in the wavelength range of 550 nm to 800 nm, and the second cutoff wavelength, which exhibits 50% transmittance in the wavelength range of 1000 nm to 1800 nm, is 600 nm or more and 800 nm or less.

6. The filter as claimed in claim 1, wherein, In the first transmission spectrum, the absolute value of the difference between the first cutoff wavelength, which exhibits 50% transmittance in the wavelength range of 550 nm to 800 nm, and the third cutoff wavelength, which exhibits 50% transmittance in the wavelength range of 350 nm to 450 nm, is greater than 200 nm and less than 270 nm.

7. The filter as claimed in claim 1, wherein, The first transmission spectrum also satisfies the following condition (viii): (viii) The maximum transmittance in the wavelength range of 1000nm to 1100nm is less than 10%.

8. The filter as claimed in claim 1, wherein, The first transmission spectrum also satisfies the following condition (ix): (ix) The minimum transmittance in the wavelength range of 1700nm to 1900nm is 60% or more.

9. The filter as claimed in claim 1, wherein, In the first transmission spectrum, the transmittance at a wavelength of 1550 nm is above 70%.

10. The filter as claimed in claim 1, wherein, The first transmission spectrum also satisfies the following condition (x): (x) The minimum transmittance in the wavelength range of 1900nm to 2200nm is 60% or more.

11. The filter as claimed in claim 1, comprising a light-absorbing layer containing a light-absorbing agent and having a thickness of 100 μm to 400 μm.

12. The filter of claim 2, further comprising a second transmission spectrum having a fourth cutoff wavelength exhibiting 50% transmittance in the wavelength range of 550 nm to 800 nm at 70°C. The absolute value of the difference between the fourth cutoff wavelength and the first cutoff wavelength is less than 15 nm.

13. The filter of claim 3, further comprising a second transmission spectrum having a fifth cutoff wavelength exhibiting 50% transmittance in the wavelength range of 1000 nm to 1800 nm at 70°C. The absolute value of the difference between the fifth cutoff wavelength and the second cutoff wavelength is less than 30 nm.

14. The filter of claim 4, further comprising a second transmission spectrum having a sixth cutoff wavelength exhibiting 50% transmittance in the wavelength range of 350 nm to 450 nm at 70°C. The absolute value of the difference between the sixth cutoff wavelength and the third cutoff wavelength is less than 15 nm.

15. An optical device comprising: A camera module that acquires image information from objects identified by visible light; A TOF sensor acquires distance measurement information from an object; and The filter according to any one of claims 1 to 14 is disposed in front of the camera module and the TOF sensor.

16. The optical device as claimed in claim 15, wherein, The TOF sensor includes: an irradiator that irradiates light with a wavelength in the range of 1500nm to 2200nm onto an object; a light receiver that receives reflected light from the object with a wavelength in the range of 1500nm to 2200nm; and a control unit.

17. A light-absorbing composition comprising: Copper complexes; At least one of a first alkoxy-containing compound having two alkoxy groups within its molecule and a hydrolysate thereof; and At least one of a second alkoxy-containing compound having three or four alkoxy groups within its molecule and a hydrolysate of the second alkoxy-containing compound. The cured product of the light-absorbing composition has a first transmission spectrum at 25°C that satisfies the following conditions (i), (ii), (iii) and (iv): (i) The minimum transmittance in the wavelength range of 450 nm to 600 nm is 70% or more; (ii) The maximum transmittance in the wavelength range of 300 nm to 370 nm is less than 5%; (iii) The maximum transmittance in the wavelength range of 800 nm to 1000 nm is less than 5%; (iv) The minimum transmittance in the wavelength range of 1500nm to 1700nm is 60% or more.

18. The light-absorbing composition of claim 17, wherein, The ratio of the content of the first alkoxy-containing compound and the content of its hydrolysate converted into a fully hydrolyzed condensate to the content of the alkoxy-containing compound and the hydrolysate of the first alkoxy-containing compound converted into a fully hydrolyzed condensate is 0.01 to 0.6 by mass.

19. The light-absorbing composition of claim 17, wherein, The ratio of the solid content of the curable resin to the content of the compound having an alkoxy group and the hydrolysate of the compound converted into a fully hydrolyzed condensate is 0 to 2 on a mass basis.

20. The light-absorbing composition of claim 17, wherein, The ratio of the content of the first alkoxy-containing compound and the hydrolysate of the first alkoxy-containing compound converted into a fully hydrolyzed condensate to the sum of the solid content of the curable resin is 0.01 to 0.4 by mass.

21. The light-absorbing composition of claim 17, wherein, The contents of aryl phosphonic acids (Cf) and alkyl phosphonic acids (Cs) satisfy a mass ratio of Cf:Cs = 50:50 to 100:0.

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