Optical laminate and method for manufacturing same

Abstract

An optical laminate having an optical functional layer on at least one surface of a substrate, the optical functional layer containing a colorant containing a plurality of pigments and a binder resin, the optical laminate having an average spectral transmittance of 25% or less at a wavelength of 350 nm to 750 nm, an average spectral transmittance of 85% or more at a wavelength of 850 nm to 2500 nm, and an average spectral transmittance of 25% or less at a wavelength of 850 nm to 2500 nm. When the maximum spectral transmittance at a wavelength of 350 nm or more and less than 460 nm is set as T1, the maximum spectral transmittance at a wavelength of 460 nm or more and less than 570 nm is set as T2, and the maximum spectral transmittance at a wavelength of 570 nm or more and 750 nm or less is set as T3, at least one of the following formulae (1A) and (2A) is satisfied, where T1 is the maximum spectral transmittance at a wavelength of 350 nm or more and less than 460 nm, T2 is the maximum spectral transmittance at a wavelength of 460 nm or more and less than 570 nm, and T3 is the maximum spectral transmittance at a wavelength of 570 nm or more and less than 750 nm. 0.1 < = T1 / T2 < = 10 (1A) 1 < = T3 / T2 < = 20 (2A)

Description

Technical Field

[0001] Embodiments of the present invention relate to an optical layered body and a method for producing the same. Background Art

[0002] Various optical system devices require technologies for controlling optical properties, such as selectively transmitting or blocking specific wavelengths of light. Optical stacks such as dichroic mirrors, bandpass filters, anti-reflection (AR) coatings, ultraviolet (UV) cutoff filters, infrared (IR) cutoff filters, and UVIR cutoff filters are used as such.

[0003] For example, infrared sensors, an example of optical system equipment, often use wavelengths in the infrared region as light sources. Typically, light-emitting diodes (LEDs) with maximum wavelengths of 850nm, 905nm, or 940nm are used. However, the light from an LED with a maximum wavelength of 850nm partially contains visible light. Therefore, to improve sensor accuracy, there is a need for an optical stack for sensors that can block visible light and transmit only infrared light.

[0004] An example of a sensor-based optical stack (hereinafter sometimes referred to as a stack) is a driver monitoring system that uses infrared light to detect the driver's movements. This system detects the driver's status by irradiating infrared light from an LED built into the vehicle's panel (Patent Document 1). By placing the sensor stack within the vehicle's panel, visible light is blocked, thereby improving sensor accuracy.

[0005] Furthermore, in recent years, the development of display-type automotive panels has progressed, incorporating various colored LEDs in addition to infrared sensors, and using these LEDs as indicator lights. In these display-type automotive panels, the LED indicator lights, which illuminate from behind the laminated structure, are expected to enhance the panel's design.

[0006] The optical stack is arranged at a position corresponding to at least the sensor sensing portion of the optical component constituting the optical system device. In the case where the optical stack is transparent or translucent, the sensor sensing portion is directly visible, and the design is poor. Therefore, from the perspective of the appearance of the optical component, the stack arranged at the position corresponding to the sensor sensing portion is preferably the same color tone as the surrounding components. In most cases, the appearance of the optical component is black, and the appearance of the optical stack is preferably black so that it is the same color tone as the surrounding components as described above. Therefore, there is a demand for an optical stack having infrared transmittance and a black appearance.

[0007] However, when using black pigments such as carbon black, there is a tendency that the infrared transmittance of the laminate is reduced and the sensor precision is reduced. In addition, the laminate can be manufactured using an ink comprising a colorant such as a pigment and a binder resin, but the dispersion state of the pigment in the ink can affect the haze value (haze value) of the coating. The haze value in the infrared region of the coating is preferably low. If the haze value in the infrared region of the coating becomes higher, there is a tendency that the infrared transmittance of the coating is reduced and the sensor precision is reduced. Therefore, it is desirable to develop a laminate with a black appearance and excellent infrared transmittance.

[0008] Furthermore, in display-type automotive panels, the light from indicator lights must be visible through an optical laminate. However, if a laminate that completely blocks visible light is used to improve infrared transmittance, the light from the indicator lights cannot be seen through the laminate. Therefore, laminates used in display-type optical system devices, such as display-type automotive panels, must strike a balance between infrared transmittance and visible light shielding.

[0009] Furthermore, for example, when a white LED display light is illuminated from behind the laminate as backlight, the driver preferably sees the display as white. However, light passing through the laminate including the infrared-transmitting layer often takes on a color different from that of the display light. This coloration of light caused by the laminate significantly reduces visibility and designability.

[0010] Therefore, there is an urgent need for the development of an optical layered body that has excellent transmittance in the infrared region and in which irradiated light and transmitted light in the visible region have the same hue.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-170958 Summary of the Invention

[0014] Problems to be solved by the invention

[0015] As described above, the present invention provides an optical laminate having excellent infrared transmittance and a black appearance. Furthermore, the present invention provides an optical laminate having excellent infrared transmittance and a black appearance, wherein the irradiated light and the transmitted light in the visible light region have the same hue.

[0016] Technical means to solve the problem

[0017] The present inventors conducted intensive research and found that the following optical layered bodies can solve the above-mentioned problems, thereby completing the present invention. Specifically, embodiments of the present invention include the following embodiments. However, the present invention is not limited to the following and includes various embodiments.

[0018] <1> An optical layered body comprising an optical functional layer on at least one surface of a substrate, wherein:

[0019] The optical functional layer comprises a colorant containing a plurality of pigments and a binder resin.

[0020] In the optical layered body,

[0021] The average spectral transmittance at wavelengths of 350nm to 750nm is less than 25%.

[0022] The average spectral transmittance of the wavelength of 850nm to 2500nm is more than 85%.

[0023] When the maximum spectral transmittance at a wavelength of 350 nm to less than 460 nm is set to T1, the maximum spectral transmittance at a wavelength of 460 nm to less than 570 nm is set to T2, and the maximum spectral transmittance at a wavelength of 570 nm to 750 nm is set to T3, at least one of the following formulas (1A) and (2A) is satisfied.

[0024] 0.1≦T1 / T2≦10(1A)

[0025] 1≦T3 / T2≦20(2A)

[0026] <2> An optical layered body comprising an optical functional layer on at least one surface of a substrate, wherein:

[0027] The optical functional layer comprises a colorant containing a plurality of pigments and a binder resin.

[0028] In the optical layered body,

[0029] The average spectral transmittance at wavelengths of 350nm to 750nm is less than 25%.

[0030] The average spectral transmittance of the wavelength of 850nm to 2500nm is more than 85%.

[0031] When the maximum spectral transmittance at a wavelength of 350 nm to less than 460 nm is set to T1, the maximum spectral transmittance at a wavelength of 460 nm to less than 570 nm is set to T2, and the maximum spectral transmittance at a wavelength of 570 nm to 750 nm is set to T3, the following equations (1) and (2) are satisfied.

[0032] 1≦T1 / T2≦10(1)

[0033] 2≦T3 / T2≦20(2)

[0034] <3> The optical layered body according to <1> or <2>, wherein the colorant containing a plurality of pigments includes a combination of yellow pigment / red pigment / blue pigment, red pigment / blue pigment / green pigment, and yellow pigment / blue pigment / violet pigment.

[0035] <4> The optical layered body according to any one of <1> to <3>, wherein the colorant containing a plurality of pigments includes a combination of a yellow pigment, a red pigment, and a blue pigment.

[0036] <5> The optical layered body according to any one of <1> to <4>, which is used for transmission vision.

[0037] <6> An optical laminate according to any one of <1> to <5>, wherein, in the color coordinates of the L*a*b* colorimetric system, the color difference (a*2-a*1) between the color coordinates (a*1, b*1) of the irradiated light from the light source to the optical laminate and the color coordinates (a*2, b*2) of the transmitted light passing through the optical laminate, and the color difference (b*2-b*1) satisfy the following equations (3) and (4).

[0038] -10<(a*2-a*1)<10 (3)

[0039] -10<(b*2-b*1)<10 (4)

[0040] <7> The optical layered body according to any one of <1> to <6>, wherein the optical function layer further contains a dispersant.

[0041] <8> The optical layered body according to any one of <1> to <7>, wherein the binder resin contains at least one selected from the group consisting of acrylic resins, polyester resins, and epoxy resins.

[0042] <9> A method for producing an optical layered body, comprising:

[0043] A step of applying a black ink containing a colorant containing a plurality of pigments and a binder resin on a substrate to form an optical function layer.

[0044] The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2023-097565, filed on June 14, 2023, and the entire disclosure is incorporated herein by reference.

[0045] Effects of the Invention

[0046] According to the present invention, an optical laminate having excellent infrared transmittance and a black appearance can be provided. In addition, according to the present invention, an optical laminate having excellent infrared transmittance and a black appearance can be provided, in which the irradiated light and the transmitted light in the visible light region have the same hue. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] [ Figure 1 ] is a graph showing the transmission spectrum of the optical layered body of Example 1 at a wavelength of 320 nm to 800 nm. DETAILED DESCRIPTION

[0048] Hereinafter, the embodiment of the present invention will be described in detail. The description of the constituent elements described below is an example (representative example) of the embodiment of the present invention. The present invention is not limited to the contents of the embodiment described below, and various modifications can be made without exceeding the gist thereof.

[0049] <Optical laminate>

[0050] An optical laminate according to one embodiment of the present invention comprises at least a substrate and an optical functional layer. The optical laminate may comprise an optical functional layer on at least one side of the substrate. The optical functional layer may be formed to cover the entire surface of the substrate or a portion thereof.

[0051] In the optical laminate of the embodiment, the optical functional layer includes a colorant containing multiple pigments and a binder resin. The optical functional layer can be formed by printing (applying) an ink containing at least a colorant and a binder resin on a substrate. That is, the optical functional layer can be a coating film (printed layer) of the ink.

[0052] The optical layered body of the embodiment is characterized in that

[0053] The average spectral transmittance at wavelengths of 350nm to 750nm is less than 25%.

[0054] The average spectral transmittance of the wavelength of 850nm to 2500nm is more than 85%.

[0055] When the maximum spectral transmittance at a wavelength of 350 nm to less than 460 nm is set to T1, the maximum spectral transmittance at a wavelength of 460 nm to less than 570 nm is set to T2, and the maximum spectral transmittance at a wavelength of 570 nm to 750 nm is set to T3, at least one of the following equations (1A) and (2A) is satisfied. In one embodiment, both equations (1A) and (2A) are preferably satisfied.

[0056] 0.1≦T1 / T2≦10(1A)

[0057] 1≦T3 / T2≦20(2A)

[0058] By including multiple pigments in the optical functional layer, the multiple pigments can be used to supplement and absorb visible light that cannot be absorbed by a single pigment. In addition, by setting the average spectral transmittance at wavelengths of 350nm to 750nm to 25% or less, an optical laminate with a high degree of blackness can be obtained, and the appearance of the peripheral components used in conjunction with the optical laminate can be made to have the same color tone (seamless). Furthermore, by setting the average spectral transmittance at wavelengths of 850nm to 2500nm to 85% or more, the laminate covering the infrared light source or infrared receiving unit and the peripheral components can be easily made to have the same color tone without compromising the sensitivity of the infrared sensor.

[0059] In the optical layered body of the embodiment, the average spectral transmittance at wavelengths of 350 nm to 750 nm can be adjusted to a value of 25% or less. In one embodiment, the average spectral transmittance is preferably 20% or less, and more preferably 15% or less. By adjusting the average spectral transmittance to 25% or less, the optical density (OD) of the optical layered body is increased, making it easier to achieve a black appearance.

[0060] The lower limit of the average spectral transmittance of a wavelength of 350nm to 750nm varies depending on the purpose of the optical laminate. For example, when the optical laminate is used for transmission vision, the lower limit of the average spectral transmittance may be 0.01%. If the average spectral transmittance is 0.01% or more, the minimum light transmittance required for transmission vision can be used. Therefore, in one embodiment, the average spectral transmittance of the wavelength of 350nm to 750nm of the optical laminate may be 0.01% to 25%. When the average spectral transmittance is adjusted to 0.01% to 25%, the optical laminate can be suitably used for transmission vision, and an optical laminate with a black appearance can be easily provided. Here, so-called transmission vision refers to the irradiation light from the light source being visible as transmitted light through the optical laminate. More preferably, it refers to the hue of the transmitted light visible through the optical laminate being no different from the irradiation light from the light source. Specific examples of applications in transmissive viewing include transmissive viewing members in display-type optical system devices such as display-type automobile panels.

[0061] On the other hand, when the optical laminate is used for purposes other than through-viewing, the average spectral transmittance may be less than 0.01%, for example, 0.00001%, or a value infinitely close to 0. By making the average spectral transmittance close to 0, the shielding property of visible light can be improved, and a black appearance with high blackness can be easily obtained. As uses other than through-viewing, for example, a cover member covering a sensor part in an optical system device can be listed. More specifically, for example, it can be suitably used as a part of a cover member covering a side-view camera of a car. The laminate has a black appearance with high blackness, so it is easy to improve the decorativeness achieved by the laminate.

[0062] The black appearance of the optical layered body can be evaluated by optical density (OD value). The OD value of the optical layered body is preferably 1 or more, more preferably 1.4 or more, and even more preferably 2 or more. The OD value is a logarithmic value representing the degree of absorption of the optical layered body when irradiated with light in the visible light range and measured by a transmission densitometer. The higher the OD value, the higher the blackness.

[0063] In the optical layered body of the embodiment, the average spectral transmittance at wavelengths of 850 nm to 2500 nm can be adjusted to a value of 85% or greater. In one embodiment, the average spectral transmittance is preferably 87% or greater, and more preferably 90% or greater. With an average spectral transmittance of 85% or greater, when used as a decorative member for an infrared sensor, interference with infrared transmission and reception can be minimized, thereby easily improving sensor sensitivity.

[0064] The optical layered body of the embodiment is characterized in that, while the average spectral transmittance at wavelengths of 350 nm to 750 nm and 850 nm to 2500 nm is within the above ranges, at least one of equations (1A) and (2A) is satisfied. By satisfying equations (1A) and / or (2A), the brightness (L* value) of reflected light from the layered body is easily brought close to zero. As a result, the layered body has a black hue, easily achieving a good black appearance.

[0065] In one embodiment, the maximum spectral transmittance "T1" of 350 nm to less than 460 nm may be present in a wavelength range of preferably 360 nm to less than 440 nm, more preferably 380 nm to less than 420 nm. The maximum spectral transmittance "T2" of 460 nm to less than 570 nm may be present in a wavelength range of preferably 480 nm to less than 560 nm, more preferably 500 nm to less than 540 nm. The maximum spectral transmittance "T3" of 570 nm to less than 750 nm may be present in a wavelength range of preferably 660 nm to less than 740 nm, more preferably 680 nm to less than 720 nm.

[0066] In one embodiment of the optical layered body, the maximum spectral transmittance "T1" of greater than 350 nm and less than 460 nm, the maximum spectral transmittance "T2" of greater than 460 nm and less than 570 nm, and the maximum spectral transmittance "T3" of greater than 570 nm and less than 750 nm may be within the ranges satisfying the following formulas (A1) and (A2).

[0067] 0.1≦T1 / T2<1(A1)

[0068] 1≦T3 / T2<2(A2)

[0069] In one embodiment of the optical layered body, the maximum spectral transmittance "T1" of 350 nm to less than 460 nm, the maximum spectral transmittance "T2" of 460 nm to less than 570 nm, and the maximum spectral transmittance "T3" of 570 nm to 750 nm preferably satisfy the following formulas (1) and (2).

[0070] 1≦T1 / T2≦10(1)

[0071] 2≦T3 / T2≦20(2)

[0072] By ensuring that T1, T2, and T3 meet the ranges of (1) and (2), it is possible to achieve a balanced transmission of blue, green, and red light, with the irradiated light and the transmitted light in the visible light region having the same hue. Therefore, the transmitted light that has passed through the laminate can directly reproduce the hue of the irradiated light from the light source. For example, when white light is used as the light source, the transmitted light is perceived as white, and when green light is used as the light source, the transmitted light is perceived as green.

[0073] In the above embodiment, T1, T2, and T3 may more preferably be within the following ranges.

[0074] 1.2≦T1 / T2≦7

[0075] 2.5≦T3 / T2≦15

[0076] The above-mentioned T1, T2 and T3 may further preferably be in the following ranges.

[0077] 1.5≦T1 / T2≦5

[0078] 3≦T3 / T2≦10

[0079] <Optical functional layer>

[0080] The optical functional layer is preferably formed from a black ink containing a colorant containing multiple pigments and a binder resin. For example, the optical functional layer is obtained by applying the black ink containing the colorant containing multiple pigments and the binder resin on a substrate and drying it. The obtained printed material becomes an optical laminate.

[0081] The thickness of the optical functional layer can be adjusted appropriately depending on its purpose and application. In one embodiment, the thickness is preferably 3 μm to 20 μm, more preferably 5 μm to 15 μm, and even more preferably 5 μm to 10 μm. When the thickness is adjusted within this range, the light-shielding properties in the visible light region are improved, and a higher black appearance is easily achieved.

[0082] Hereinafter, the ink that can be used to form the optical functional layer will be described.

[0083] The ink comprises a colorant containing multiple pigments and a binder resin. From the perspective of achieving a black coating film, the colorant containing multiple pigments preferably has a black hue. In one embodiment, the combination of multiple pigments may include, for example, a blue pigment, a yellow pigment, and a red pigment. In this way, by combining at least three pigments, a black ink can be formed that can easily achieve a black appearance in an optical laminate. Specific examples of black inks are described below.

[0084] [Black ink]

[0085] Black ink contains a colorant including multiple pigments and a binder resin.

[0086] (colorant)

[0087] The colorant contains multiple pigments, which are mixed and used. By containing multiple pigments, the blackness of the appearance of the optical laminate can be ensured, thereby achieving seamlessness due to the same color design as the surrounding members, and adding design characteristics.

[0088] As coloring agent, various organic pigments, inorganic pigments, dyes etc. can be listed. Pigment is preferably a pigment with high color development and high heat resistance, preferably an organic pigment. Among organic pigments, a combination of yellow pigment / red pigment / blue pigment, a combination of red pigment / blue pigment / green pigment, a combination of yellow pigment / blue pigment / violet pigment etc. can be listed. With regard to the viewpoint of uniform shielding property in the visible light region, in the combination of multiple pigments, it is preferred to include at least one of yellow pigment, red pigment and blue pigment. In addition to the pigments, in the scope that does not hinder the effect of the present invention, complementary color pigments such as orange pigment, green pigment, violet pigment can also be used.

[0089] Specific examples of organic pigments that can be used as colorants are shown below using pigment index numbers. In addition, "CI (Colour Index)" described in this specification refers to the Pigment Index (CI).

[0090] As yellow pigments, CI Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 20, 24, 31, 32, 34, 35, 35:1, 36, 36:1, 37, 37:

[0091] 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 86, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 125, 126, 127, 128, 129, 137, 138, 139, 147, 148, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 198, 199, 213, 214, 218, 219, 220, 221, 231, etc.

[0092] Although not particularly limited, in one embodiment, the yellow pigment may include at least one selected from the group consisting of CI Pigment Yellow 110, 150, and 139.

[0093] As red pigments, CI Pigment Red 7, 9, 14, 41, 48:1, 48:2, 48:3, 48:4, 57:1, 81, 81:1, 81:2, 81:3, 81:4, 97, 122, 123, 146, 149, 150, 168, 169, 176, 177, 178, 180, 184, 185, 187, 192, 200, 202, 208, 209, 210, 215, 216, 217, 220, 223, 224, 226, 227, 228, 240, 242, 246, 254, 255, 264, 268, 270, 272, 273, 274, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, etc.

[0094] Although not particularly limited, in one embodiment, the red pigment may include at least one selected from the group consisting of CI Pigment Red 122, 254, and 264.

[0095] As the blue pigment, CI Pigment Blue 1, 1:2, 1:3, 2, 2:1, 2:2, 3, 8, 9, 10, 10:1, 11, 12, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 18, 19, 22, 24, 24:1, 53, 56, 56:1, 57, 58, 59, 60, 61, 62, 64, etc. can be preferably used.

[0096] Although not particularly limited, in one embodiment, the yellow pigment may include at least one selected from the group consisting of CI Pigment Blue 15:3, 15:4, and 15:6.

[0097] As the orange pigment, CI Pigment Orange 36, 38, 43, 51, 55, 59, 61, 71, 73 and the like can be preferably used.

[0098] Although not particularly limited, in one embodiment, the orange pigment may include at least one selected from the group consisting of CI Pigment Orange 43, 71, and 73.

[0099] As the green pigment, CI Pigment Green 7, 10, 36, 37, 58, 62, 63 and the like can be preferably used.

[0100] Although not particularly limited, in one embodiment, the green pigment may include at least one selected from the group consisting of CI Pigment Green 7, 10, and 36.

[0101] As the violet pigment, CI Pigment Violet 1, 19, 27, 29, 30, 32, 37, 40, 42, 50 and the like can be preferably used.

[0102] Although not particularly limited, in one embodiment, the violet pigment may include at least one selected from the group consisting of CI Pigment Violet 23, 27, and 29.

[0103] Examples of inorganic pigments include titanium oxide, carbon black, aluminum paste, mica, bronze powder, chromium vermilion, chrome yellow, cadmium yellow, cadmium red, ultramarine, iron blue, Indian red, yellow iron oxide, and iron black. Examples of extender pigments include silicon dioxide, aluminum oxide, talc, calcium carbonate, and precipitated barium. Inorganic pigments are preferably used in combination with organic pigments to achieve a balance between chroma and brightness while ensuring good coating properties, sensitivity, and developability.

[0104] When using black ink containing carbon black, a black coating film can be easily obtained. However, as the carbon black content in the optical functional layer increases, the transmittance in the infrared region decreases. From this perspective, the carbon black content in the optical functional layer is preferably less than 2.5% by mass based on the total mass of the optical functional layer. When the carbon black content is adjusted to less than 2.5% by mass, the transmittance in the infrared region can be easily adjusted to 85% or above.

[0105] The content may be, more preferably, 1.0% by mass or less, and further preferably 0.5% by mass or less. In one embodiment, the optical functional layer preferably does not substantially contain carbon black. Here, "substantially not containing" means that it is not intentionally used, and its content may be 0.1% by mass or less, or 0% by mass.

[0106] The content of the colorant in the total solid content of the black ink (in the total mass of the optical functional layer) is preferably 10% by mass to 45% by mass, more preferably 15% by mass to 40% by mass, and even more preferably 20% by mass.

[0107] % to 35% by mass. By adjusting the colorant content within this range, light-shielding properties are improved, and a more black appearance can be achieved. Here, the colorant content in the optically functional layer corresponds to the ratio of the colorant content to the total mass of the solid components in the black ink. The same applies to the solid content of the pigment, binder resin, etc. described below.

[0108] In the optical laminate of the present invention, from the perspective of satisfying the above-mentioned transmittance, in the case of a combination of yellow pigment / red pigment / blue pigment, the total solid content of the black ink (the total mass of the optical functional layer) preferably contains 0.1% to 10% by mass of yellow pigment, 0.1% to 10% by mass of red pigment, and 0.1% to 10% by mass of blue pigment. More preferably, it contains 0.1% to 4% by mass of yellow pigment, 0.1% to 8% by mass of red pigment, and 0.1% to 8% by mass of blue pigment. Further preferably, it contains 0.1% to 3% by mass of yellow pigment, 0.1% to 6% by mass of red pigment, and 0.1% to 6% by mass of blue pigment.

[0109] The mixing ratio of the pigments is preferably yellow pigment / red pigment / blue pigment = 5-40 / 5-60 / 5-60, more preferably 10-30 / 10-50 / 10-50, and even more preferably 10-30 / 25-50 / 25-50, relative to the total amount of the pigments.

[0110] When CI Pigment Yellow 139 is used as the yellow pigment, CI Pigment Red 264 is used as the red pigment, and CI Pigment Blue 15:6 is used as the blue pigment, since excellent shielding properties in the visible light region can be exhibited, which is preferable.

[0111] In the case of a red pigment / blue pigment / green pigment combination, the red pigment is preferably contained at a ratio of 0.1% to 10% by mass, the blue pigment is contained at a ratio of 0.1% to 10% by mass, and the green pigment is contained at a ratio of 0.1% to 10% by mass in the total solid content of the black ink (in the total mass of the optical functional layer). More preferably, the red pigment is contained at a ratio of 0.1% to 8% by mass, the blue pigment is contained at a ratio of 0.1% to 4% by mass, and the green pigment is contained at a ratio of 0.1% to 8% by mass. Further preferably, the red pigment is contained at a ratio of 0.1% to 6% by mass, the blue pigment is contained at a ratio of 0.1% to 3% by mass, and the green pigment is contained at a ratio of 0.1% to 6% by mass.

[0112] The mixing ratio of the pigments is preferably red pigment / blue pigment / green pigment = 5-60 / 5-40 / 5-60, more preferably 10-50 / 10-30 / 10-50, and even more preferably 30-50 / 20-30 / 30-50, relative to the total amount of the pigments.

[0113] It is preferable to use CI Pigment Red 264 as the red pigment, CI Pigment Blue 15:6 as the blue pigment, and CI Pigment Green 7 as the green pigment.

[0114] In the case of a combination of yellow pigment / blue pigment / violet pigment, the yellow pigment is preferably contained at a ratio of 0.1% to 10% by mass, the blue pigment is contained at a ratio of 0.1% to 10% by mass, and the violet pigment is contained at a ratio of 0.1% to 10% by mass in the total solid content of the black ink (in the total mass of the optical functional layer). More preferably, the yellow pigment is contained at a ratio of 0.1% to 8% by mass, the blue pigment is contained at a ratio of 0.1% to 4% by mass, and the violet pigment is contained at a ratio of 0.1% to 8% by mass. Further preferably, the yellow pigment is contained at a ratio of 0.1% to 6% by mass, the blue pigment is contained at a ratio of 0.1% to 3% by mass, and the violet pigment is contained at a ratio of 0.1% to 6% by mass.

[0115] The mixing ratio of the pigments is preferably yellow pigment / blue pigment / violet pigment = 5-60 / 5-40 / 5-60, more preferably 10-50 / 10-30 / 10-50, and even more preferably 30-50 / 20-30 / 30-50, relative to the total amount of the pigments.

[0116] It is preferable to use CI Pigment Yellow 139 as the yellow pigment, CI Pigment Blue 15:6 as the blue pigment, and CI Pigment Violet 23 as the violet pigment.

[0117] In addition, in the case of a combination of yellow pigment / red pigment / violet pigment, the yellow pigment is preferably contained at a ratio of 0.1% to 10% by mass, the red pigment is contained at a ratio of 0.1% to 10% by mass, and the violet pigment is contained at a ratio of 0.1% to 10% by mass in the total solid content of the black ink (in the total mass of the optical functional layer). More preferably, the yellow pigment is contained at a ratio of 0.1% to 8% by mass, the red pigment is contained at a ratio of 0.1% to 4% by mass, and the violet pigment is contained at a ratio of 0.1% to 8% by mass. Further preferably, the yellow pigment is contained at a ratio of 0.1% to 6% by mass, the red pigment is contained at a ratio of 0.1% to 3% by mass, and the violet pigment is contained at a ratio of 0.1% to 6% by mass.

[0118] The mixing ratio of the pigments is preferably yellow pigment / red pigment / violet pigment = 5-60 / 5-40 / 5-60, more preferably 10-50 / 10-30 / 10-50, and even more preferably 30-50 / 20-30 / 30-50, relative to the total amount of the pigments.

[0119] It is preferable to use CI Pigment Yellow 139 as the yellow pigment, CI Pigment Red 264 as the red pigment, and CI Pigment Violet 23 as the violet pigment.

[0120] (Binder resin)

[0121] Binder resin refers to a resin that can function as an adhesive in a coloring ink, and can be a thermoplastic resin or a thermosetting resin, preferably a thermoplastic resin. As thermoplastic resins, for example, acrylic resins, polyester resins, epoxy resins, styrene resins, rosin resins, styrene-maleic acid resins, dammar resins, polycarbonate resins, rosin-modified maleic acid resins, rosin ester resins, terpene resins, carbamate resins, etc. These resins can be used in combination within the scope of not damaging the effect of the present invention. Thermoplastic resins that can react with crosslinking agents such as isocyanates can also be used as thermosetting resins.

[0122] From the perspective of adhesion to the substrate during formation of the coating film (optical functional layer), the binder resin preferably comprises at least one selected from the group consisting of acrylic resins, polyester resins, and epoxy resins in the thermoplastic resin. The binder resin more preferably comprises an acrylic resin. When the binder resin comprises an acrylic resin, the content of the acrylic resin in the binder resin is preferably 70% by mass or more, and more preferably 80% by mass or more, based on the total mass of the binder resin.

[0123] When the binder resin includes an acrylic resin, the acid value of the acrylic resin is preferably 20 mgKOH / g or less, more preferably 15 mgKOH / g or less, further preferably 10 mgKOH / g or less, further preferably 5 mgKOH / g or less, and particularly preferably 1 mgKOH / g or less.

[0124] When the binder resin includes an acrylic resin, the hydroxyl value of the acrylic resin is preferably 1 mgKOH / g or more, more preferably 10 mgKOH / g or more, further preferably 20 mgKOH / g or more, and particularly preferably 25 mgKOH / g or more.

[0125] When the binder resin includes an acrylic resin, the reactive functional group value of the acrylic resin (the sum of the acid value and the hydroxyl value) is preferably 1 mgKOH / g to 50 mgKOH / g, more preferably 5 mgKOH / g to 40 mgKOH / g, and even more preferably 10 mgKOH / g to 35 mgKOH / g.

[0126] The term "acrylic resin" as used herein refers to a copolymer of (meth)acrylic acid and a (meth)acrylic acid derivative such as a (meth)acrylic acid ester. As monomers forming the copolymer, monomers having an ethylenically unsaturated bond other than (meth)acrylic acid and (meth)acrylic acid derivatives may be used. Examples include styrene.

[0127] In one embodiment, a (meth)acrylic acid derivative may be a compound in which the hydrogen atom of the carboxyl group is substituted with an alkyl group or a hydroxyalkyl group. The alkyl group may have 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms. Examples include ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. The same applies to the alkyl group of the hydroxyalkyl group. Examples of such compounds include 2-hydroxyethyl (meth)acrylate.

[0128] Although not particularly limited, the acrylic resin may be a copolymer of (meth)acrylic acid / alkyl (meth)acrylate / hydroxyalkyl (meth)acrylate / styrene. More specifically, it may be a copolymer of (meth)acrylic acid / stearyl (meth)acrylate / methyl (meth)acrylate / 2-hydroxyethyl (meth)acrylate / styrene.

[0129] The weight average molecular weight of the binder resin is preferably 5000 to 120000, more preferably 20000 to 100000, and even more preferably 30000 to 80000. When a binder resin having a weight average molecular weight within the above range is used, printability can be easily improved.

[0130] The content of the binder resin in the total solid content of the black ink (total mass of the optical functional layer) is preferably 40% to 80% by mass, more preferably 45% to 75% by mass, and even more preferably 50% to 70% by mass. This is to improve dispersion stability.

[0131] The mass ratio of the total amount of colorant to the binder resin in the total solid content of the black ink (in the total mass of the optical functional layer) is preferably 85 / 15 to 60 / 40, more preferably 80 / 20 to 65 / 35. This ratio improves light-shielding properties and achieves a more black appearance.

[0132] The black ink used to form the optical functional layer may further contain a photocurable resin as a binder resin in addition to the thermoplastic resin. However, when a photocurable resin is used, there is a tendency for the curing to be insufficient and the light resistance to be poor. In addition, when a curable resin such as an acrylic monomer is present in the ink system, the compatibility balance is sometimes destroyed and the dispersion state of the pigment becomes unstable. For unstable pigments, stabilization is desired, and there is a tendency to achieve stabilization through coagulation. The pigment particles after coagulation will diffusely reflect light, so the haze value tends to become higher. Therefore, when a photocurable resin is used, the transmittance in the near-infrared region is reduced, which may become a cause of reduced sensitivity of the sensor.

[0133] From this perspective, the content of the thermoplastic resin in the binder resin is preferably 60% by mass or greater. Based on the total mass of the binder resin, the content of the thermoplastic resin is more preferably 70% by mass or greater, and even more preferably 80% by mass or greater. In one embodiment, the content of the thermoplastic resin may be 100% by mass.

[0134] (Dispersant)

[0135] The black ink used to form the optically functional layer preferably also contains a dispersant. Dispersants in black ink inhibit pigment aggregation and improve dispersion stability, and more preferably have a comb-like structure. In this specification, "comb-like structure" refers to the structure of a (co)polymer formed by bonding repeating units as side chains to the main chain. A comb-like dispersant improves dispersion stability.

[0136] The dispersant preferably has an acidic group, and more preferably has an acid value of 0.1 mgKOH / g to 100 mgKOH / g. The dispersant having an acidic group prevents light in the visible region from passing through, thereby exhibiting excellent shielding properties.

[0137] The content of the dispersant is preferably 1% to 25% by mass, more preferably 2% to 20% by mass, and even more preferably 3% to 15% by mass, based on the total solid content of the black ink (the total mass of the optical functional layer). By adjusting the dispersant content within this range, compatibility with the binder resin is maintained, and turbidity of the coating film is prevented, thereby maintaining the transparency of the coating film.

[0138] The weight average molecular weight of the dispersant is preferably 10,000 to 100,000, more preferably 10,000 to 50,000, and further preferably 10,000 to 30,000. If the weight average molecular weight is 10,000 or more, steric repulsion that contributes to dispersion stability can be obtained to prevent aggregation of the pigment. If the weight average molecular weight is 100,000 or less, compatibility with the solvent can be maintained, and the dispersion stability of the pigment can be maintained. For example, "Malialim SC-1015F" (comb-shaped structure, weight average molecular weight 20,000) manufactured by NOF Corporation can be suitably used.

[0139] (Organic solvent)

[0140] The black ink may contain an organic solvent. Examples of the organic solvent include glycol ether organic solvents, ester organic solvents, aliphatic organic solvents, aromatic organic solvents, alcohol organic solvents, and cyclic ketone organic solvents. Among them, cyclic ketone organic solvents are preferred due to their good printability.

[0141] (Defoaming Agent)

[0142] The black ink preferably contains a defoaming agent. The content of the defoaming agent is preferably 0.1% to 5% by mass, and more preferably 0.3% to 4% by mass, relative to the total mass of the black ink.

[0143] In one embodiment, the viscosity of the black ink used to form the optical functional layer is preferably 0.1 Pa·s to 60 Pa·s, more preferably 0.3 Pa·s to 30 Pa·s, and even more preferably 0.5 Pa·s to 10 Pa·s at 25° C. When the viscosity of the ink is adjusted within this range, good printability is achieved.

[0144] <Formation of optical functional layer>

[0145] In the optical laminate of the embodiment, the optical functional layer can be formed by applying the black ink onto a substrate. Application methods include, for example, screen printing, roller coating, dispenser coating, dip coating, and brush application. Among these, screen printing, dispenser coating, and dip coating are preferred. A cylinder press or semi-automatic printing press is preferably used as the printing press, and a resin material such as nylon or polyester, or a resin material such as stainless steel is preferably used as the printing plate.

[0146] While not particularly limited, screen printing is preferred from the perspectives of film thickness and printability on molded products. Screen printing is a technique in which a screen made of chemical fibers such as polyester and nylon, or stainless steel, is patterned with a photosensitive emulsion to create areas where ink passes through and areas where it does not. A blade-like rubber sheet, called a squeegee, is then used to pressurize and move the ink across the inner surface of the screen, transferring the ink to a substrate. The thickness of the printed ink can be adjusted by adjusting the thickness of the photosensitive emulsion applied to the substrate surface.

[0147] After printing, a hot air oven is used to evaporate the solvent in the ink, thereby fixing the ink to the substrate.

[0148] <Base material>

[0149] The substrate used to form the optical layered body is not particularly limited, but is preferably a transparent substrate. Examples thereof include inorganic substrates such as glass, polyester substrates such as polyethylene terephthalate, polyethylene, polypropylene, ethylene-vinyl acetate and other polyolefin substrates, nylon substrates such as polyamide, acrylic substrates such as polymethyl methacrylate, polyvinyl chloride substrates, polycarbonate substrates, polyurethane substrates, epoxy substrates, cycloolefin polymers (COP), cycloolefin copolymers (COC) and other cyclic olefin substrates, and other resin substrates. A laminate of these may also be used.

[0150] Alternatively, a vapor deposition substrate may be used on which an inorganic compound such as silica, alumina, or aluminum is vapor deposited, and the vapor deposition surface may be coated with polyvinyl alcohol, etc. Alternatively, a corona treatment, flame treatment, or stretching treatment may be performed.

[0151] Among the above, inorganic material substrates such as glass, polyester substrates such as polyethylene terephthalate, acrylic substrates such as polymethyl methacrylate (PMMA), and polycarbonate substrates are preferred.

[0152] The optical laminate of the embodiment described above may further comprise a protective layer for protecting the optical functional layer, in addition to a substrate and an optical functional layer. The protective layer improves light resistance, weather resistance, scratch resistance, and other resistance properties. The protective layer preferably does not hinder the desired effects of the present invention, such as infrared transmittance and visible light shielding. For example, the optical functional layer may be formed by coating a transparent resin such as a thermoplastic resin on the upper surface. Alternatively, the transparent substrate may be bonded to the upper surface of the optical functional layer using an adhesive.

[0153] <Method for producing an optical layered body>

[0154] The optical layered body of the embodiment can be manufactured by a manufacturing method, the manufacturing method comprising the step of applying a black ink containing a colorant containing multiple pigments and a binder resin on a substrate to form an optical functional layer. In addition, the present invention provides a method for manufacturing an optical layered body, wherein the average spectral transmittance at a wavelength of 350 nm to 750 nm is 25% or less, the average spectral transmittance at a wavelength of 850 nm to 2500 nm is 85% or more, and the following formula (1A) and formula (2A) are satisfied when the maximum spectral transmittance at a wavelength of 350 nm to less than 460 nm is set to T1, the maximum spectral transmittance at a wavelength of 460 nm to less than 570 nm is set to T2, and the maximum spectral transmittance at a wavelength of 570 nm to less than 750 nm is set to T3.

[0155] 0.1≦T1 / T2≦10(1A)

[0156] 1≦T3 / T2≦20(2A)

[0157] The method for producing the black ink is not particularly limited, and a known method may be applied. For example, a method may be mentioned in which a colorant, a binder resin, and an organic solvent are uniformly stirred with a stirrer, dispersed with a bead mill, and filtered with a filter.

[0158] The printing conditions for the black ink are not particularly limited. Preferred application methods include screen printing, dispenser coating, and dip coating. Preferred printing presses include cylinder presses and semi-automatic presses. Preferred printing plates include resin materials such as nylon and polyester, and resin materials such as stainless steel.

[0159] <Usage Forms of the Optical Laminate>

[0160] As the purpose of the optical laminate of one embodiment of the present invention, if it is an optical system device, it is not particularly limited. For example, components of automobiles, components for household appliances, etc. can be listed. In addition, it is also suitable as an optical component such as an optical filter used in an infrared sensor of a smart phone, etc. In particular, it can be suitably used as the through-viewing component. In this specification, the so-called through-viewing refers to the visual recognition of the light irradiated on the optical laminate from the side opposite to the light source across the optical laminate.

[0161] More specifically, since the optical layered body has a black appearance, it can be used to form a cover member that also serves as an optical filter for an infrared sensor. An example of such a use is an infrared sensor cover including the optical layered body.

[0162] In addition, a sensor unit including an infrared sensor and a light source is combined with the optical laminate of the embodiment to form a display-type sensor panel. The optical laminate is arranged on the front surface of the sensor unit so that light from the light source can pass through and be visually recognized. In the embodiment, the light source irradiating the optical laminate is not particularly limited, but preferably an incandescent bulb, an organic electroluminescence (EL) lamp, or a light-emitting diode (LED) is used.

[0163] According to the optical properties of the optical laminate of this embodiment, it is preferred that the hue of the irradiated light (incident light) irradiated from the light source to the optical laminate and the light (transmitted light) perceived through the optical laminate be the same or have little difference. In other words, it is preferred that the color difference between the irradiated light and the transmitted light be small.

[0164] In one embodiment, in the color coordinates of the L*a*b* colorimetric system, the color difference (a*2-a*1) between the color coordinates (a*1, b*1) of the irradiated light from the light source to the optical stack and the color coordinates (a*2, b*2) of the transmitted light passing through the optical stack, and the color difference (b*2-b*1) may satisfy the following equations (3) and (4).

[0165] -10<(a*2-a*1)<10 (3)

[0166] -10<(b*2-b*1)<10 (4)

[0167] When the color difference satisfies the above formulas (3) and (4), the color difference between the irradiated light and the transmitted light is reduced, and thus, it is easy to make the hue of the light from the light source and the light visible through the optical laminate the same. From this point of view, the color difference is preferably further reduced. In one embodiment, the color difference is preferably within the range of the following formulas (5) and (6).

[0168] -5<(a*2-a*1)<5 (5)

[0169] -5<(b*2-b*1)<5 (6)

[0170] The color coordinates a* and b* of the L*a*b* color system are values ​​expressed as color coordinates according to the color system of the Commission Internationale de l'Eclairage (CIE) (1976), based on the values ​​obtained by irradiating the optical laminate with light and measuring it with a spectrophotometer. The measurement can be performed in accordance with Japanese Industrial Standards (JIS) Z8781-4.

[0171] Example

[0172] The present invention will be described in detail below using examples, but the present invention is not limited to the following examples. In the present invention, "parts" means "parts by mass" and "%" means "% by mass" unless otherwise specified.

[0173] <1> Example of ink preparation

[0174] <1-1> Synthesis of Binder Resin

[0175] <Synthesis example 1>

[0176] (Synthesis of Acrylic Resin 1)

[0177] In a four-necked flask equipped with a stirrer, a reflux cooling tube, a nitrogen inlet tube, an inlet tube, and a thermometer, 300 g of methyl ethyl ketone (MEK) was placed and heated to 80° C. while nitrogen was injected into the container. A mixture of 38 g of methyl methacrylate (MMA), 53 g of butyl methacrylate (BMA), 16 g of 2-hydroxyethyl methacrylate (HEMA), 13 g of styrene (St), and 0.8 g of 2,2′-azobisisobutyronitrile (AIBN) was added dropwise at the temperature over 1 hour to carry out a polymerization reaction. After completion of the dropwise addition, the mixture was reacted at 80°C for 3 hours, and then 1.2 parts of 2,2'-azobisisobutyronitrile dissolved in 100 g of isophorone was added and reacted at 80°C for 1 hour to obtain acrylic resin 1 (weight average molecular weight 40,000, acid value 0.3 mgKOH / g, hydroxyl value 30 mgKOH / g).

[0178] <3-2> Preparation of black ink

[0179] <Preparation Example 1>

[0180] (Black ink S1)

[0181] The following ink raw materials, namely, micronized pigments of various colors, a dispersing resin, and isophorone, were stirred and mixed until uniform. The mixture was dispersed in an Eiger Mill (Mini Model M-250MKII, manufactured by Eiger Japan) using 0.5 mm diameter zirconia beads for 5 hours. The mixture was then filtered through a 5 μm filter to obtain a mixed color pigment dispersion.

[0182] (Ink raw materials)

[0183] Yellow micronized pigment CI Pigment Yellow 139

[0184] (LIONOGEN YELLOW 1090) 2 servings

[0185] Red micronized pigment CI Pigment Red 264

[0186] 4 parts of Cinilex DPP Rubine SR6T

[0187] Blue micronized pigment CI Pigment Blue 15:6

[0188] (LIONOGEN BLUE 7703) 4 servings

[0189] Dispersants

[0190] 5 parts (Malialim SC-1015F manufactured by NOF Corporation, comb-shaped structure, weight average molecular weight 20,000)

[0191] 35 parts of isophorone

[0192] To the obtained mixed color pigment dispersion, 49 parts of the previously prepared acrylic resin 1 solution (resin / isophorone = 24 / 25) and 1 part of a defoamer ("BYK-054" manufactured by BYK-Chemie Japan) were added. These were uniformly mixed using a rotary mixer to obtain black ink S1.

[0193] <Preparation Examples 2 to 21>

[0194] (Preparation of Black Inks S2 to S14 and T1 to T7)

[0195] By the same method as in Preparation Example 1, black inks S2 to S14 and T1 to T7 were obtained using the raw materials and blending ratios shown in Tables 1 and 2, respectively.

[0196] The abbreviations in Tables 1 and 2 are as follows: Unless otherwise specified, the numerical values ​​in the tables represent "parts", and blank fields indicate that they were not used.

[0197] (pigment)

[0198] CI Pigment Yellow 139

[0199] (Product name: "LIONOGEN YELLOW 1090" manufactured by Toyo Color Co., Ltd.)

[0200] CI Pigment Red 264 (product name "Cinilex DPP Rubine SR6T" manufactured by Kikuchi Color Co., Ltd.)

[0201] CI Pigment Blue 15:6

[0202] (Product name: Lionogen Blue 770, manufactured by Toyo Color Co., Ltd.)

[0203] CI Pigment Violet 23

[0204] (Product name: Lionogen Violet FG-6240, manufactured by Toyo Color Co., Ltd.)

[0205] CI Pigment Green 7

[0206] (Product name: "LIONOGEN GREEN 8944" manufactured by Toyo Color Co., Ltd.)

[0207] CI Pigment Black 10

[0208] (Product name "Mitsubishi Carbon Black MA8" manufactured by Mitsubishi Chemical Corporation)

[0209] (Binder resin)

[0210] Ultraviolet (UV) curable resin: EBECRYL 8606

[0211] (Manufactured by Daicel-Allnex, weight average molecular weight 1400)

[0212] Polyester resin: VYLON GK250

[0213] (Manufactured by Toyobo Co., Ltd., number average molecular weight 10,000, acid value <2 mgKOH / g, hydroxyl value 11 mgKOH / g)

[0214] Epoxy resin: JER1010

[0215] (Made by Mitsubishi Chemical Co., Ltd., number average molecular weight 5000, acid value <2 mgKOH / g)

[0216] Urethane resin: Polylite OD-X-2523

[0217] (Manufactured by DIC Corporation, molecular weight 3500, acid value 0.5 mgKOH / g, hydroxyl value 32 mgKOH / g)

[0218] (Photopolymerization initiator)

[0219] Omnirad TPO (manufactured by IGM, 2,4,6-trimethylbenzoyldiphenylphosphine oxide)

[0220] <2> Production of optical laminate

[0221] <Production Example 1>

[0222] (Manufacturing of SS1 Optical Laminated Body)

[0223] A micro slide glass (MICRO SLIDE GLASS) (manufactured by Matsunami Glass Co., Ltd., large slide glass S9213, film thickness 1 mm) is used as a substrate, and a screen printing plate (manufactured by NBC Meshtec, L-SCREEN, 250-015 / 255PW) is used on the substrate to screen-print the black ink S1 to print a pattern, thereby forming an optical functional layer with a film thickness of 7 μm, and obtaining an optical laminate SS1.

[0224] <Production Examples 2 to 25>

[0225] (Manufacture of optical laminates SS2 to SS14, TT1 to TT7, and UU1 to UU4)

[0226] Optical layered bodies SS2 to SS14, TT1 to TT7, and UU1 to UU3 were obtained by the same method as in Production Example 1, except that the black ink S1 used in Example 1 was replaced with the black inks listed in Tables 1 and 2. Furthermore, black ink U4 containing a UV-curable resin was screen-printed in the same manner as in Production Example 1, and then irradiated with UV light (using a metal halide lamp) to cure the coating film, thereby obtaining optical layered body UU4. Ultraviolet light irradiation was adjusted to a conveyor speed of 10 m / min, 120 W / cm, and an irradiation distance of 15 mm.

[0227] <3> Evaluation of optical laminates

[0228] About the optical layered bodies obtained in Production Examples 1 to 25 (film thickness of the optical functional layer: 7 μm), various characteristics were evaluated as follows.

[0229] <Spectral transmittance of optical laminate>

[0230] The optical laminate was measured for spectral transmittance in the following wavelength range using a UV3600 ultraviolet-visible-near-infrared spectrophotometer manufactured by Shimadzu Corporation. The measured values ​​were evaluated according to the following criteria. The results are shown in Tables 1 and 2.

[0231] (Average spectral transmittance at wavelengths of 350nm to 750nm)

[0232] A: Less than 10%

[0233] B: More than 10% and less than 25%

[0234] C: More than 25%

[0235] (Average spectral transmittance at wavelengths of 850nm to 2500nm)

[0236] A: More than 90%

[0237] B: 85% or more and less than 90%

[0238] C: less than 85%

[0239] <Evaluation 1 of Optical Properties of Optical Laminated Body>

[0240] About the optical layered body, T1, T2, and T3 described below were measured using UV3600 ultraviolet-visible-near-infrared spectrophotometer manufactured by Shimadzu Corporation.

[0241] Maximum spectral transmittance at wavelengths above 350nm and below 460nm: T1

[0242] Maximum spectral transmittance at wavelengths above 460nm and below 570nm: T2

[0243] Maximum spectral transmittance at wavelengths above 570 nm and below 750 nm: T3

[0244] The values ​​of T1 / T2 and T2 / T3 were calculated from the obtained measured values, and the results were evaluated according to the following criteria.

[0245] (T1 / T2 Evaluation 1 Criteria)

[0246] ○: 0.1 ≤ T1 / T2 ≤ 10 (satisfies formula (1A))

[0247] ×: T1 / T2<0.1, or 10<T1 / T2 (does not satisfy formula (1A))

[0248] (Based on Evaluation 1 of T3 / T2)

[0249] ○: 1 ≤ T3 / T2 ≤ 20 (satisfies formula (2A))

[0250] ×: T3 / T2<1, 20<T3 / T2 (does not satisfy formula (2A))

[0251] <OD value (optical density) of optical laminate>

[0252] For optical laminates, the OD value in the visible light region was measured using a transmission densitometer (Gretag Macbeth TD-931). The measured values ​​were evaluated according to the following criteria. The results are shown in Tables 1 and 2. The higher the OD value, the darker the black. A rating of "B" or higher indicates a practical level.

[0253] A: OD value 1.4 or above

[0254] B: OD value is greater than 1 and less than 1.4

[0255] C: OD value is less than 1

[0256] <Haze value>

[0257] The haze value of the optical laminate in the infrared region (wavelength 850nm) was measured using a haze meter HSP-150VIR manufactured by Murakami Color Research Laboratory Co., Ltd. The measurement was carried out according to the method described in JIS K7361. The measured values ​​were evaluated according to the following criteria. The results are shown in Tables 1 and 2. A rating of "B" or above indicates a practical level.

[0258] A: Haze value less than 3%

[0259] B: Haze value is more than 3% and less than 10%

[0260] C: Haze value exceeds 10%

[0261]

[0262]

[0263] As shown in Tables 1 and 2, optical layered products SS1 to SS14, TT2 to TT5, and UU1 to UU4, whose T1 / T2 and T3 / T2 values ​​are within the ranges specified by Formula (1A) and / or Formula (2A), are black with high OD values, have excellent transmittance in the infrared region (wavelength 850 nm to 2500 nm), and are also excellent in terms of haze values. Specifically, optical layered products SS1 to SS10 and TT2 to TT5 exhibited favorable haze evaluation results under 850 nm wavelength light compared to optical layered products SS11 to SS14 and UU1 to UU4.

[0264] An ink containing no dispersant was used for optical laminate SS11, and an ink containing a thermoplastic resin other than acrylic resin as a binder resin was used for optical laminates SS12 to SS14. Furthermore, an ink containing an acrylic resin and a resin other than acrylic resin as a binder resin was used for optical laminates UU1 to UU3. An ink containing an acrylic resin and a UV-curable resin as a binder resin was used for optical laminate UU4.

[0265] This shows that a good optical layered body with a low haze value can be easily formed by adding a dispersant to the ink or increasing the content of the acrylic resin in the binder resin.

[0266] On the other hand, the optical laminate TT1, whose average spectral transmittance at wavelengths of 350 nm to 750 nm exceeded 25%, resulted in a low OD value and poor optical density. Furthermore, the optical laminate TT7, which used carbon black, showed poor transmittance in the infrared region (wavelengths of 850 nm to 2500 nm).

[0267] <Evaluation 2 of Optical Properties of Optical Laminated Body>

[0268] The T1 / T2 and T3 / T2 values ​​calculated in Evaluation 1 described above were evaluated according to the following criteria to form Evaluation 2. The results are shown in Tables 3 and 4. For reference, Tables 3 and 4 also show the evaluation results of the average spectral transmittance at wavelengths of 350 nm to 750 nm, the average spectral transmittance at wavelengths of 850 nm to 2500 nm, and the OD value (optical density) described above.

[0269] (T1 / T2 Evaluation 2 Criteria)

[0270] A: 1.5≦T1 / T2≦5

[0271] B: 1≦T1 / T2<1.5, 5<T1 / T2≦10

[0272] C: T1 / T2<1, 10<T1 / T2

[0273] (T3 / T2 evaluation criteria 2)

[0274] A: 3≦T3 / T2≦10

[0275] B: 2≦T3 / T2<3, 10<T3 / T2≦20

[0276] C: T3 / T2<2, 20<T3 / T2

[0277] Color of transmitted light

[0278] The optical layered body was irradiated with white light or green light from a light source, and the color of the light transmitted through the optical layered body was visually confirmed and evaluated. The evaluation criteria are as follows. The results are shown in Tables 3 and 4. If the evaluation is "B" or above, it is a practical level.

[0279] A: Same color as the irradiated light (no discoloration)

[0280] B: A slightly different color from the light being irradiated (slight discoloration)

[0281] C: A color different from the irradiated light (discoloration occurs)

[0282] Color difference

[0283] According to the method described in JIS Z8781-4, the optical laminate was irradiated with light at an incident angle of 90 degrees, and the color coordinates (a*2, b*2) expressed in the L*a*b* color system of CIE (1976) were determined using a spectral haze meter SH7000 manufactured by Nippon Denshoku Industries Co., Ltd. Separately, the color coordinates (a*1, b*1) of the substrate of the optical laminate (microslide glass (large slide glass S9213 manufactured by Matsunami Glass Co., Ltd., film thickness 1 mm)) were determined using the same method as described above.

[0284] Next, color differences (a*2 - a*1) and (b*2 - b*1) were calculated from the color coordinates and evaluated according to the following criteria. The results are shown in Tables 3 and 4. In the following evaluation criteria, (a*2 - a*1) is represented as a*, and (b*2 - b*1) is represented as b*. A rating of "B" or higher indicates a practical level.

[0285] A: -5<a*<5, -5<b*<5

[0286] B: -10<a*<10, -10<b*<10

[0287] C: a*≦-10 or 10≦a*, b*≦-10 or 10≦b*

[0288]

[0289]

[0290] The optical laminates SS1 to SS14 and UU1 to UU4 in which the values ​​of T1 / T2 and T3 / T2 are within the ranges specified in formula (1) and formula (2) relate to a preferred embodiment of the present invention. According to Tables 3 and 4, in the optical laminates SS1 to SS14 and UU1 to UU4, the irradiated light and the transmitted light in the visible light region have the same hue (for example, the transmitted light when irradiated with white light is white). In addition, the optical laminates have a high OD value, excellent transmittance in the infrared region, and the irradiated light and the transmitted light in the visible light region have the same hue (the transmitted light when irradiated with white light is white). As can be seen from this, they can be suitably used as a transparent visual component.

[0291] On the other hand, in the optical layered product TT1, whose average spectral transmittance at wavelengths of 350 nm to 750 nm exceeded 25%, visible light transmittance was excellent, but the OD value was low. Furthermore, in the optical layered products TT2 to TT6, whose T1 / T2 and T3 / T2 values ​​were outside the ranges specified by equations (1) and (2), the irradiated light and the transmitted light in the visible light region were not the same color, resulting in poor visibility. Furthermore, in the optical layered product TT7 using carbon black, visible light was barely transmitted, making it impossible to identify the color of the transmitted light, and infrared transmittance was poor.

Claims

1. An optical laminate comprising: a substrate; and an optical functional layer located on at least one side of the substrate, wherein: The optical functional layer comprises a colorant containing a plurality of pigments and a binder resin. In the optical layered body, The average spectral transmittance at wavelengths of 350nm to 750nm is less than 25%. The average spectral transmittance of the wavelength of 850nm to 2500nm is more than 85%. When the maximum spectral transmittance at a wavelength of 350 nm to less than 460 nm is set to T1, the maximum spectral transmittance at a wavelength of 460 nm to less than 570 nm is set to T2, and the maximum spectral transmittance at a wavelength of 570 nm to 750 nm is set to T3, at least one of the following formulas (1A) and (2A) is satisfied, 0.1≦T1 / T2≦10(1A) 1≦T3 / T2≦20(2A).

2. The optical laminate according to claim 1, wherein The T1, T2, and T3 satisfy the following formulas (1) and (2): 1≦T1 / T2≦10(1) 2≦T3 / T2≦20(2).

3. The optical layered body according to claim 1 or 2, wherein In the colorant, the plurality of pigments include any one of a combination of yellow pigment / red pigment / blue pigment, red pigment / blue pigment / green pigment, and yellow pigment / blue pigment / violet pigment.

4. The optical layered body according to any one of claims 1 to 3, wherein In the colorant, the plurality of pigments include a combination of yellow pigment / red pigment / blue pigment. The optical layered body according to any one of claims 1 to 4, which is used for transmission vision.

6. The optical layered body according to any one of claims 1 to 5, wherein In the color coordinates of the L*a*b* colorimetric system, the color difference (a*2-a*1) and the color difference (b*2-b*1) between the color coordinates (a*1, b*1) of the irradiated light from the light source to the optical layered body and the color coordinates (a*2, b*2) of the transmitted light passing through the optical layered body satisfy the following equations (3) and (4). -10<(a*2-a*1)<10 (3) -10<(b*2-b*1)<10 (4).

7. The optical layered body according to any one of claims 1 to 6, wherein The optically functional layer further includes a dispersant.

8. The optical layered body according to any one of claims 1 to 7, wherein The binder resin includes at least one selected from the group consisting of acrylic resin, polyester resin, and epoxy resin.

9. A method for producing an optical laminate, comprising the step of applying a black ink containing a colorant containing a plurality of pigments and a binder resin on a substrate to form an optical functional layer, wherein: In the optical layered body, The average spectral transmittance at wavelengths of 350nm to 750nm is less than 25%. The average spectral transmittance of the wavelength of 850nm to 2500nm is more than 85%. When the maximum spectral transmittance at a wavelength of 350 nm to less than 460 nm is set to T1, the maximum spectral transmittance at a wavelength of 460 nm to less than 570 nm is set to T2, and the maximum spectral transmittance at a wavelength of 570 nm to 750 nm is set to T3, at least one of the following formulas (1A) and (2A) is satisfied, 0.1≦T1 / T2≦10(1A) 1≦T3 / T2≦20(2A).

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