JP6939243B2 - Capacitive sensor encapsulation resin composition and capacitive sensor - Google Patents

Description

The present invention relates to a resin composition for encapsulating a capacitance type sensor and a capacitance type sensor.

Various technologies are being studied for capacitive sensors. For example, Patent Document 1 studies a semiconductor fingerprint sensor that detects fingerprint information by a capacitance method.
Patent Document 1 describes a fingerprint reading sensor in which a plurality of electrodes are arranged in an array on a substrate such as silicon via an interlayer film, and the upper surface thereof is overcoated with an insulating film (sealing film). There is.

Japanese Unexamined Patent Publication No. 2004-234245

In recent capacitance type sensors, a surface coating may be applied on an insulating film (sealing film). In such a case, it is desirable to form a light-colored insulating film (sealing film) from the viewpoint of preventing the color of the insulating film (sealing film) from being transparent and improving the color development of the surface coating film. It is said that. However, in order to form the above-mentioned light-colored insulating film (sealing film), it is necessary to form the insulating film (sealing film) using a resin composition that does not contain a colorant such as carbon black. .. However, when the present inventor forms a light-colored insulating film (sealing film), the present invention uses the insulating film (sealing film) when using a capacitance type sensor provided with such a light-colored insulating film (sealing film). It was found that there is a possibility that inconveniences such as a gradual change in the hue of) may occur. In addition, the present inventor also has the inconvenience that when the above-mentioned inconvenience occurs, the color-developing property of the surface coating film coated on the insulating film (sealing film) gradually decreases. I found it.

Therefore, in the present invention, when an insulating film is produced using a resin composition for encapsulating a capacitive sensor and a surface coating film is formed on the insulating film, the color development property of the surface coating film deteriorates with time. A resin composition for encapsulating a capacitance type sensor and a capacitance type sensor are provided.

According to the present invention, it is a resin composition for sealing a capacitance type sensor used for forming a sealing film in a capacitance type sensor.
Epoxy resin and
Hardener and
Filler and
Including
The content of the epoxy resin is 6.2% by mass or more in 100% by mass of the solid content of the resin composition for encapsulating the capacitance type sensor.
The content of the curing agent is 5.8% by mass or less in 100% by mass of the solid content of the resin composition for encapsulating the capacitance type sensor.
The curing agent contains a biphenyl aralkyl type phenol resin.
For the cured product of the capacitance type sensor encapsulating resin composition, the value of the brightness L of the cured product calculated from the Hunter Lab color system using a spectrophotometer is 25 or more.
The chromaticity of the first test piece calculated from the Hunter Lab color system using a spectrophotometer for the first test piece made of the resin composition for encapsulating the capacitance type sensor obtained under the following condition 1. Let the value of b be b0
With respect to the second test piece made of the capacitance type sensor sealing resin composition obtained under the following condition 2, the chromaticity of the second test piece calculated from the Hunter Lab color system using a spectrophotometer. When the value of b is b1,
Provided is a resin composition for encapsulating a capacitance type sensor, wherein the value of Δb calculated by the formula b1-b0 is 0 or more and 30 or less.
(Condition 1: The cured product obtained by heat-treating the resin composition for encapsulating the capacitance type sensor at 175 ° C. for 3 minutes is used as the first test piece.)
(Condition 2: The cured product obtained by heat-treating the resin composition for encapsulating the capacitance type sensor at 175 ° C. for 3 minutes and then heat-treating at 175 ° C. for 4 hours is the second. Use as a test piece.)

Further, according to the present invention, the substrate and
With the detection electrode provided on the substrate,
A sealing film that seals the detection electrode and is composed of a cured product of the resin composition for encapsulating a capacitance type sensor.
Capacitive sensors are provided.

According to the present invention, when an insulating film is produced using a resin composition for encapsulating a capacitive sensor and a surface coating film is formed on the insulating film, the color development property of the surface coating film deteriorates with time. A resin composition for encapsulating a capacitance type sensor and a capacitance type sensor can be provided.

It is sectional drawing which shows typically the capacitance type sensor which concerns on this embodiment.

Hereinafter, embodiments will be described with reference to the drawings. In all drawings, similar components are designated by the same reference numerals, and description thereof will be omitted as appropriate.

<Resin composition for encapsulating capacitance type sensor>
The resin composition for encapsulating a capacitance type sensor according to the present embodiment (hereinafter, also referred to as the present resin composition) is used for forming a sealing film in a capacitance type sensor. The resin composition contains an epoxy resin, a curing agent, and a filler, and the cured product of the resin composition is calculated from the Hunter Lab color system using a spectrocolorimeter. The value of the brightness L of the cured product is 25 or more. Further, in the present resin composition, the chromaticity of the first test piece composed of the resin composition obtained under the following condition 1 is calculated from the Hunter Lab color system using a spectrophotometer. The chromaticity b of the second test piece calculated from the Hunter Lab color system using a spectrophotometer for the second test piece made of the resin composition obtained under the following condition 2 with the value of b being b0. When the value of is b1, the value of Δb calculated by the formula of b1-b0 is 0 or more and 30 or less. By doing so, even when a light-colored insulating film (sealing film) is formed using the present resin composition, the change in color tone of the insulating film (sealing film) is suppressed over time. It becomes possible.
(Condition 1: The cured product obtained by heat-treating the resin composition at 175 ° C. for 3 minutes is used as the first test piece.)
(Condition 2: The cured product obtained by heat-treating the resin composition at 175 ° C. for 3 minutes and then heat-treating at 175 ° C. for 4 hours is used as the second test piece.)

Here, for the cured product of the present resin composition, the value of the brightness L of the cured product calculated from the Hunter Lab color system using a spectrocolorimeter is 25 or more, but preferably 25 or more and 72 or less. It is more preferably 30 or more and 60 or less. That is, the color of the cured product of the present resin composition is preferably so-called white or gray, and more preferably so-called gray. By doing so, it becomes possible to produce a light-colored insulating film (sealing film) required for a capacitance type sensor in recent years with a high yield.

Further, in the present embodiment, the above-mentioned value of Δb is 0 or more and 30 or less, but it is preferable from the viewpoint of effectively suppressing the change in color tone of the insulating film (sealing film) for a long period of time. It is 1 or more and 28 or less, more preferably 2 or more and 25 or less, and further preferably 2 or more and 15 or less.

In the present embodiment, the value of Δb can be controlled by appropriately adjusting the type and content of each component contained in the resin composition, the particle size distribution of the resin composition, and the like. In the present embodiment, for example, the use of a phenol resin curing agent that is less likely to cause discoloration due to oxidation, and control of the balance between the blending amount of the colorant and the blending amount of the epoxy resin, the curing agent and the filler. The value of Δb can be controlled by taking measures such as.

Further, in the present embodiment, for the first test piece obtained under the above condition 1, the value of the brightness L of the first test piece calculated from the Hunter Lab color system using a spectrophotometer is set to L0, and the above Regarding the second test piece made of the present resin composition obtained under Condition 2, when the value of the brightness L of the second test piece calculated from the Hunter Lab color system using a spectrophotometer is L1, L1- The value of ΔLa calculated by the formula of L0 is preferably −3.5 or more and 5 or less, more preferably -3.3 or more and 4 or less, and further preferably -3.2 or more and 2 or less. By doing so, it is possible to realize an excellent capacitance type sensor from the viewpoint that the color change is unlikely to occur in the thermal history.

In the present embodiment, the value of ΔLa can be controlled by appropriately adjusting the type and content of each component contained in the resin composition, the particle size distribution of the resin composition, and the like. In the present embodiment, for example, the use of a phenol resin curing agent that is less likely to cause discoloration due to oxidation, and control of the balance between the blending amount of the colorant and the blending amount of the epoxy resin, the curing agent and the filler. The value of ΔLa can be controlled by taking measures such as.

Further, in the present embodiment, with respect to the third test piece made of the present resin composition obtained under the following condition 3, the brightness L of the third test piece calculated from the Hunter Lab color system using a spectrophotometer is used. When the value is L2, the second test piece composed of the value of L2 and the present resin composition obtained under the above condition 2 is calculated from the Hunter Lab color system using a spectrophotometer. From the value L1 of the brightness L of one piece, the value of ΔLb calculated by the formula of L2-L1 is preferably -6 or more and 0 or less, more preferably -5.5 or more and 0 or less, and -1. It is more preferable that it is 5 or more and −0.5 or less. By doing so, it is possible to realize an excellent capacitance type sensor from the viewpoint that the color change is unlikely to occur in the thermal history.
(Condition 3: The cured product obtained by heat-treating the resin composition at 175 ° C. for 3 minutes and then heat-treating at 175 ° C. for 8 hours is used as the third test piece).

In the present embodiment, the value of ΔLb can be controlled by appropriately adjusting the type and content of each component contained in the resin composition, the particle size distribution of the resin composition, and the like. In the present embodiment, for example, the use of a phenol resin curing agent that is less likely to cause discoloration due to oxidation, and control of the balance between the blending amount of the colorant and the blending amount of the epoxy resin, the curing agent and the filler. The value of ΔLb can be controlled by taking measures such as.

Hereinafter, the present resin composition will be described in detail.

(Epoxy resin)
As the epoxy resin, a monomer, an oligomer, or a polymer having two or more epoxy groups in one molecule can be used in general, and the molecular weight and molecular structure thereof are not particularly limited.
In the present embodiment, examples of the epoxy resin include biphenyl type epoxy resin; bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetramethyl bisphenol F type epoxy resin and other bisphenol type epoxy resin; stillben type epoxy resin; phenol novolac. Novolak type epoxy resin such as type epoxy resin and cresol novolac type epoxy resin; polyfunctional epoxy resin such as triphenylmethane type epoxy resin and alkyl modified triphenylmethane type epoxy resin; phenol aralkyl type epoxy resin having phenylene skeleton, biphenylene skeleton Aralkill type epoxy resin such as phenol aralkyl type epoxy resin (biphenyl aralkyl type epoxy resin); naphthol type epoxy resin such as dihydroxynaphthalene type epoxy resin and epoxy resin obtained by glycidyl etherification of a dimer of dihydroxynaphthalene; Triazine nuclei-containing epoxy resins such as glycidyl isocyanurate and monoallyl diglycidyl isocyanurate; Aribashi cyclic hydrocarbon compound-modified phenolic epoxy resins such as dicyclopentadiene-modified phenol-type epoxy resin can be mentioned, and one of these can be used alone. It may be used or two or more types may be used in combination.
Of these, from the viewpoint of improving the balance between moisture resistance reliability and moldability, aralkyl type epoxy resins such as bisphenol type epoxy resin, novolak type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, and triphenylmethane It is more preferable to contain at least one of the type epoxy resins, and it is particularly preferable to contain at least one of the aralkyl type epoxy resins such as the biphenyl type epoxy resin and the biphenyl aralkyl type epoxy resin.

The epoxy resin includes an epoxy resin containing a structural unit represented by the following formula (1), an epoxy resin containing a structural unit represented by the following formula (2), and a structural unit represented by the following formula (3). It is preferable to contain at least one selected from the group consisting of epoxy resins containing the above, and the epoxy resin containing the structural unit represented by the following formula (1) or the structural unit represented by the following formula (2). It is more preferable to contain an epoxy resin containing.

（式（１）中、Ａｒ^１はフェニレン基またはナフチレン基を表し、Ａｒ^１がナフチレン基の場合、グリシジルエーテル基はα位、β位のいずれに結合していてもよい。Ａｒ^２はフェニレン基、ビフェニレン基またはナフチレン基のうちのいずれか１つの基を表す。Ｒ_ａおよびＲ_ｂは、それぞれ独立に炭素数１〜１０の炭化水素基を表す。ｇは０〜５の整数であり、ｈは０〜８の整数である。ｎ^３は重合度を表し、その平均値は１〜３である。）

(In the formula (1), Ar ¹ represents a phenylene group or a naphthylene group, and when Ar ¹ is a naphthylene group, the glycidyl ether group may be bonded to either the α-position or the β-position ^{. Ar 2} is a phenylene group. , A group of any one of a biphenylene group and a naphthalene group. _Ra and R _b each independently represent a hydrocarbon group having 1 to 10 carbon atoms. G is an integer of 0 to 5, and h. Is an integer from 0 to 8. n ³ represents the degree of polymerization, and the average value thereof is 1 to 3.)

（式（２）中、複数存在するＲ_ｃは、それぞれ独立に水素原子または炭素数１〜４の炭化水素基を表す。ｎ^５は重合度を表し、その平均値は０〜４である。）

(In the formula (2), a plurality of R _cs independently represent a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. N ⁵ represents the degree of polymerization, and the average value thereof is 0 to 4. )

（式（３）中、複数存在するＲ_ｄおよびＲ_ｅは、それぞれ独立に水素原子又は炭素数１〜４の炭化水素基を表す。ｎ^６は重合度を表し、その平均値は０〜４である。）

(In the formula (3), a plurality of R _d and _Re each independently represent a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. N ⁶ represents the degree of polymerization, and the average value thereof is 0 to 4. Is.)

The content of the epoxy resin in the resin composition is preferably 2.0% by mass or more, preferably 3.0% by mass or more, when the entire resin composition (total solid content) is 100% by mass. It is more preferably 4.0% by mass or more, and even more preferably 6.2% by mass or more. It is considered that one of the reasons why the color tone of the cured product of the conventional capacitive sensor encapsulating resin composition changes with time is that the reactive group contained in the curing agent changes with time. As an example, the phenolic hydroxyl group contained in the curing agent changes to quinone with time, so that the color of the cured product of the conventional resin composition for encapsulating a capacitive sensor changes. When the content of the epoxy resin is at least the above numerical range, the reactive group with the epoxy resin contained in the curing agent can be appropriately consumed. As a result, it is possible to suppress changes in the color development property of the present resin composition over time.
On the other hand, the content of the epoxy resin in the present resin composition is preferably 30% by mass or less, preferably 20% by mass or less, when the entire resin composition (total solid content) is 100% by mass. It is more preferable, and it is particularly preferable that it is 10% by mass or less. By setting the content of the epoxy resin to the above upper limit value or less, it is possible to improve the moisture resistance reliability and the reflow resistance of the capacitance type sensor using the cured product of the present resin composition as the sealing film.

(filler)
The filler according to the present embodiment is not particularly limited as long as it has a relative permittivity (1 MHz) of 5 or more, but for example, from the viewpoint of being able to particularly improve the relative permittivity of the cured product of the obtained resin composition. It is preferable to use one or more selected from silica, alumina, titanium oxide and barium titanate, and one or two selected from silica, alumina and barium titanate from the viewpoint of suppressing oxidative deterioration of the resin. It is more preferable to use the above.
Further, in the present embodiment, from the viewpoint of maintaining the sensitivity of the capacitance type sensor in a good state while suppressing the change in color tone of the insulating film (sealing film) with time, the average particle size (D _50). ) Are different, it is preferable to use two or more kinds of fillers in combination.

The content of the filler in the resin composition is preferably 50% by mass or more, more preferably 60% by mass or more, when the entire resin composition (total solid content) is 100% by mass. It is preferably 70% by mass or more, and particularly preferably 70% by mass or more. By setting the content of the filler to the above lower limit value or more, the dielectric property of the present resin composition can be further improved, and the sensitivity of the capacitance type sensor can be further improved.
On the other hand, the content of the filler in the resin composition is preferably 90% by mass or less, preferably 89% by mass or less, when the entire resin composition (total solid content) is 100% by mass. Is more preferable. By setting the content of the filler to the above upper limit value or less, it is possible to more effectively improve the fluidity and the filling property at the time of molding of the present resin composition.

The average particle size D ₅₀ of the filler is 0.2 μm or more and 8 μm or less, and preferably 1 μm or more and 5 μm or less. By setting the average particle size D ₅₀ to the above lower limit value or more, the fluidity of the present resin composition can be improved and the moldability can be improved more effectively. Further, by setting the average particle size D ₅₀ to the above upper limit value or less, it is possible to surely suppress the occurrence of gate clogging and the like.
The average particle size D ₅₀ is measured by measuring the particle size distribution of the particles on a volume basis using a commercially available laser particle size distribution meter (for example, SALD-7000 manufactured by Shimadzu Corporation), and the median diameter (D) thereof. ₅₀ ) can be the average particle size D ₅₀ .

(Hardener)
The resin composition can contain, for example, a curing agent. The curing agent is not particularly limited as long as it is cured by reacting with an epoxy resin, but for example, a linear aliphatic diamine having 2 to 20 carbon atoms such as ethylenediamine, trimethylenediamine, tetramethylenediamine, and hexamethylenediamine. , Metaphenylenediamine, paraphenylenediamine, paraxylene diamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 4,4 Amines such as'-diaminodicyclohexane, bis (4-aminophenyl) phenylmethane, 1,5-diaminonaphthalene, metaxylene diamine, paraxylene diamine, 1,1-bis (4-aminophenyl) cyclohexane, dicyanodiamide, etc. Resol-type phenol resin such as aniline-modified resol resin and dimethyl ether resol resin; Novolak-type phenol resin such as phenol novolac resin, cresol novolac resin, tert-butylphenol novolac resin, nonylphenol novolac resin; triphenylmethane-type phenol resin (triphenylmethane) Polyfunctional phenol resin such as type phenol resin); phenol aralkyl resin containing phenylene skeleton, phenol aralkyl resin containing biphenylene skeleton (biphenyl aralkyl type phenol resin); condensed polycyclic structure such as naphthalene skeleton and anthracene skeleton Phenol resins such as naphthol aralkyl type phenol resins having Acid anhydrides and the like containing aromatic acid anhydrides such as (TMA), pyromellitic anhydride (PMDA), benzophenone tetracarboxylic acid (BTDA); and polymercaptan compounds such as polysulfides, thioesters and thioethers; isocyanate prepolymers, blocks. Examples thereof include isocyanate compounds such as phenol formaldehyde; and organic acids such as carboxylic acid-containing polyester resin. One of these may be used alone, or two or more thereof may be used in combination.
Of the above specific examples, for example, a phenol resin is preferably used as the curing agent. Further, as the phenol resin, it is preferable to use at least one selected from the group consisting of, for example, a triphenylmethane type phenol resin, a biphenyl aralkyl type phenol resin, and a naphthol aralkyl type phenol resin among the above specific examples. .. As a result, it is possible to suppress the formation of a color-developing structure due to the oxidation of the curing agent. Therefore, it is possible to suppress the change in color of the cured product of the resin composition of the present embodiment with time.

The upper limit of the content of the curing agent in the resin composition is, for example, preferably 20% by mass or less, preferably 15% by mass or less, when the entire resin composition (total solid content) is 100% by mass. It is more preferably 10% by mass or less, and further preferably 5.8% by mass or less. Thereby, the absolute amount of the unreacted curing agent can be reduced. Therefore, it is possible to prevent the unreacted curing agent contained in the cured product of the present resin composition from causing discoloration.
The lower limit of the content of the curing agent in the resin composition is preferably 0.5% by mass or more, for example, when the entire resin composition (total solid content) is 100% by mass. It is more preferably 1.5% by mass or more, and further preferably 2.0% by mass or more. Thereby, the present resin composition can be appropriately cured.

(Coupling agent)
The present resin composition can contain, for example, a coupling agent. Examples of the coupling agent include various silane compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, and vinylsilane, and known coupling agents such as titanium compounds, aluminum chelates, and aluminum / zirconium compounds. Can be used.
Examples of these are vinyl trichlorosilane, vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tris (β-methoxyethoxy) silane, γ-methacryloxypropyl trimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxy. Silane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane , Vinyl triacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropylmethyldimethoxysilane, γ- [bis (β-hydroxyethyl) ] Aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, N-β- (aminoethyl)- γ-Aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane (phenylaminopropyltrimethoxysilane), γ- (β-aminoethyl) aminopropyldimethoxymethylsilane, N- (trimethoxysilylpropyl) Ethylenediamine, N- (dimethoxymethylsilylisopropyl) ethylenediamine, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, γ-chloro Propyltrimethoxysilane, hexamethyldisilane, vinyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, 3-isocyanuppropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-triethoxysilyl-N- (1, Silane-based coupling agents such as hydrolyzate of 3-dimethyl-butylidene) propylamine, isopropyltriisostearoyl titanate, isopropyltris (dioctylpyrophosphate) titanate, isopropyltri (N-aminoethyl-aminoethyl) titanate, tetraoctyl Bis (ditridecylphosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) ) Phenyl phosphite titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (dioctylpyrophosphate) ethylene titanate, isopropyltrioctanoyl titanate, isopropyldimethacrylisostearoyl titanate, isopropyltridodecylbenzenesulfonyl titanate, isopropylisostearoyl diacrylic titanate , Isopropyltri (dioctylphosphate) titanate, isopropyltricylphenyl titanate, tetraisopropylbis (dioctylphosphate) titanate and other titanate-based coupling agents. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the coupling agent in the resin composition is not particularly limited, but is, for example, 0.01% by mass or more and 3% by mass or less when the entire resin composition (total solid content) is 100% by mass. It is preferably 0.1% by mass or more and 2% by mass or less. By setting the content of the coupling agent to the above lower limit value or more, the dispersibility of the filler in the present resin composition can be improved. Further, by setting the content of the coupling agent to the above upper limit value or less, the fluidity of the present resin composition can be improved and the moldability can be improved.

(Other ingredients)
In addition to the above components, the present resin composition contains phosphorus atoms such as, for example, an organic phosphine, a tetra-substituted phosphonium compound, a phosphobetaine compound, an adduct of a phosphine compound and a quinone compound, or an adduct of a phosphonium compound and a silane compound. Containing compounds, or amidine compounds such as 1,8-diazabicyclo [5.4.0] undecene-7 and imidazole, tertiary amines such as benzyldimethylamine, amidinium salts which are quaternary onium salts of the above compounds, or ammonium. Curing accelerators such as nitrogen atom-containing compounds typified by salts; colorants such as carbon black; natural waxes, synthetic waxes such as stearyl alcohol-modified olefin / maleic acid copolymers, higher fatty acids or metal salts thereof, paraffins, Release agent such as polyethylene oxide; polybutadiene compound, acrylonitrile-butadiene copolymer compound such as acrylonitrile-butadiene rubber, low stress agent such as silicone oil and silicone rubber; ion trapping agent such as hydrotalcite; difficulty such as aluminum hydroxide Fuel agent: Various additives such as antioxidants can be included.
In addition, tetraphenylphosphonium / bisphenol S salt and tetraphenylphosphonium / 2,3-dihydroxynaphthalene salt can also be contained in the present resin composition as the above-mentioned curing accelerator.

When the present resin composition contains the above-mentioned colorant, the content thereof is determined from the viewpoint of effectively suppressing the change in color tone of the insulating film (sealing film) produced by using the present resin composition over time. For example, when the entire resin composition (total solid content) is 100% by mass, it may be 0.15% by mass or less, 0.1% by mass or less, or 0.05% by mass or less. good.
When the present resin composition contains the above-mentioned colorant, the content of the colorant may be, for example, 0.01% by mass or more.

_{The relative permittivity (ε r} ) of the cured product of the present resin composition at 1 MHz is, for example, preferably 4 or more, more preferably 5 or more, further preferably 6.5 or more, and 7 It is more preferably 0.0 or more. When the relative permittivity (ε _r ) is at least the above lower limit value, the dielectric properties of the present resin composition can be further improved. As a result, when the present resin composition is used for the capacitance type sensor, the sensitivity of the capacitance type sensor can be further improved.
The cured product of the present resin composition can be obtained, for example, by compression molding the resin composition using a compression molding machine under the conditions of a mold temperature of 175 ° C., a molding pressure of 9.8 MPa, and a curing time of 300 seconds. .. This cured product has, for example, a diameter of 50 mm and a thickness of 3 mm.
The relative permittivity (ε _r ) of the cured product can be measured by, for example, Q-METER 4342A manufactured by Yokogawa-Hewlett-Packard.
The upper limit of the relative permittivity (ε _r ) is not particularly limited, but is, for example, 300 or less.

The dielectric loss tangent (tan δ) of the cured product of the present resin composition at 1 MHz is preferably 0.005 or more, more preferably 0.006 or more, and further preferably 0.007 or more.
When the dielectric loss tangent (tan δ) is at least the above lower limit value, the dielectric property of the present resin composition can be further improved, and the sensitivity of the capacitance type sensor can be further improved.
The cured product of the present resin composition can be obtained by, for example, compression molding the present resin composition using a compression molding machine under the conditions of a mold temperature of 175 ° C., a molding pressure of 9.8 MPa, and a curing time of 300 seconds. .. This cured product has, for example, a diameter of 50 mm and a thickness of 3 mm.
The dielectric loss tangent (tan δ) of the cured product can be measured by, for example, Q-METER 4342A manufactured by Yokogawa-Hewlett-Packard.
The upper limit of the dielectric loss tangent (tan δ) is not particularly limited, but is, for example, 0.07 or less.

The relative permittivity (ε _r ) and the dielectric loss tangent (tan δ) can be controlled by appropriately adjusting the type and blending ratio of each component constituting the present resin composition. In the present embodiment, particularly appropriate selection of the type and content of the filler _{is mentioned as a factor for controlling the relative permittivity (ε r} ) and the dielectric loss tangent (tan δ). For example, the more the inorganic filler having a large dielectric constant is used, the more the relative permittivity (ε _r ) and the dielectric loss tangent (tan δ) of the cured product of the present resin composition can be improved.

The flow length of the present resin composition measured by spiral flow measurement is preferably, for example, 30 cm or more and 200 cm or less. Thereby, the moldability of the present resin composition can be improved. For the spiral flow measurement of this resin composition, for example, using a transfer molding machine, a mold for spiral flow measurement according to EMMI-1-66 has a mold temperature of 175 ° C., an injection pressure of 9.8 MPa, and an injection time of 15. This is performed by injecting the present resin composition under the conditions of seconds and a curing time of 120 to 180 seconds, and measuring the flow length.

The glass transition temperature of the cured product of the present resin composition is preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and particularly preferably 140 ° C. or higher. Thereby, the heat resistance of the capacitance type sensor can be improved more effectively. On the other hand, the upper limit of the glass transition temperature is not particularly limited, but can be, for example, 250 ° C. or lower.

The coefficient of linear expansion (CTE1) of the cured product of the present resin composition at a glass transition temperature or lower is preferably 3 ppm / ° C. or higher, and more preferably 6 ppm / ° C. or higher. The coefficient of linear expansion (CTE1) at the glass transition temperature or lower is, for example, preferably 50 ppm / ° C. or lower, and more preferably 30 ppm / ° C. or lower. By controlling the CTE1 in this way, it is possible to more reliably suppress the warp of the capacitance type sensor due to the difference in the linear expansion coefficient between the substrate (for example, a silicon chip) and the sealing film.

The coefficient of linear expansion (CTE2) of the cured product of the present resin composition when the glass transition temperature is exceeded is preferably 10 ppm / ° C. or higher. Further, the coefficient of linear expansion (CTE2) when the glass transition temperature is exceeded is preferably 100 ppm / ° C. or less, for example. By controlling CTE2 in this way, the warpage of the capacitance type sensor due to the difference in the coefficient of linear expansion between the substrate (for example, a silicon chip) and the sealing film can be more reliably suppressed, especially in a high temperature environment. Can be done.

The glass transition temperature of the cured product of the present resin composition and the coefficient of linear expansion (CTE1, CTE2) can be measured, for example, as follows.
The cured product of the present resin composition can be obtained by, for example, compression molding the present resin composition using a compression molding machine under the conditions of a mold temperature of 175 ° C., a molding pressure of 9.8 MPa, and a curing time of 300 seconds. .. This cured product has, for example, a length of 10 mm, a width of 4 mm, and a thickness of 4 mm.
Next, the obtained cured product was post-cured at 175 ° C. for 4 hours, and then using a thermomechanical analyzer (TMA100 manufactured by Seiko Electronics Inc.), the measurement temperature range was 0 ° C. to 320 ° C., and the temperature rising rate. The measurement is performed under the condition of 5 ° C./min. From this measurement result, the glass transition temperature, the coefficient of linear expansion below the glass transition temperature (CTE1), and the coefficient of linear expansion above the glass transition temperature (CTE2) are calculated.

The flexural modulus of the cured product of the present resin composition at 260 ° C. is preferably 400 MPa or more. The flexural modulus at 260 ° C. is preferably 1500 MPa or less, for example.
By controlling the flexural modulus at 260 ° C. in this way, it is possible to suppress the deformation of the sealing film especially after the curing step until it is cooled to room temperature, and the subsequent warpage of the capacitance type sensor can be suppressed. Can be suppressed more reliably.
Further, by setting the flexural modulus at 260 ° C. to the above upper limit value or less, external stress and thermal stress are effectively relaxed to improve solder resistance and the like, and the reliability of the capacitance type sensor is improved. It is possible to improve the sex.

The flexural modulus of the cured product of the present resin composition at 260 ° C. can be measured, for example, as follows.
The cured product of the present resin composition can be obtained by, for example, compression molding the present resin composition using a compression molding machine under the conditions of a mold temperature of 175 ° C., a molding pressure of 9.8 MPa, and a curing time of 300 seconds. .. This cured product has, for example, a length of 80 mm, a width of 10 mm, and a thickness of 4 mm.
Next, the obtained cured product is post-cured at 175 ° C. for 4 hours, and then the flexural modulus of the cured product at 260 ° C. is measured according to JIS K 6911.

The coefficient of linear expansion (CTE1) and the coefficient of linear expansion (CTE2) relating to the cured product of the present resin composition are the types and contents of each component contained in the resin composition, the particle size distribution of the present resin composition, and the like. It is possible to control by adjusting each appropriately. In the present embodiment, for example, by increasing the content of the filler and improving the crosslink density of the resin component used, the coefficient of linear expansion (CTE1) relating to the cured product of the present resin composition is obtained. And the value of the coefficient of linear expansion (CTE2) can be controlled.

Further, the flexural modulus at 260 ° C. of the cured product of the present resin composition can be controlled by appropriately adjusting the type and blending ratio of each component constituting the present resin composition. In the present embodiment, for example, the value of the flexural modulus at 260 ° C. of the cured product of the present resin composition can be controlled by taking measures such as increasing the content of the filler.

<Manufacturing method of resin composition for encapsulating capacitance type sensor>
Hereinafter, a method for producing the present resin composition will be described.
The present resin composition can be made into granules by mixing and kneading the above components and then using various methods such as pulverization, granulation, extrusion cutting and sieving alone or in combination. As a method for obtaining granules, for example, each raw material component is premixed with a mixer, heat-kneaded with a kneader such as a roll, a kneader or an extruder, and then a cylindrical outer peripheral portion having a plurality of small holes and a disk shape. A method in which a melt-kneaded resin composition is supplied to the inside of a rotor composed of the bottom surface of the rotor, and the resin composition is passed through a small hole by a centrifugal force obtained by rotating the rotor (centrifugal milling). Method); A method obtained by kneading in the same manner as described above, then cooling and pulverizing to obtain a pulverized product by removing coarse particles and fine powder using a sieve (crushing sieve separation method); each raw material component. After premixing with a mixer, heat kneading is performed using an extruder equipped with a die having a plurality of small diameters arranged at the tip of the screw, and the molten resin is extruded into a strand shape from the small holes arranged in the die. Is obtained by cutting with a cutter that slides and rotates substantially parallel to the die surface (hereinafter, also referred to as “hot cut method”). In any of the methods, a granular capacitive sensor encapsulating resin composition having a desired particle size distribution can be obtained by selecting kneading conditions, centrifugal conditions, sieving conditions, cutting conditions, and the like. ..

<Capacitive sensor>
Hereinafter, the configuration of the capacitance type sensor 100 according to the present embodiment will be described in detail.

The capacitance type sensor 100 according to the present embodiment is, for example, a fingerprint sensor that reads fingerprint information by a capacitance method that senses the capacitance with a finger. Here, the fingerprint sensor reads the unevenness of the finger placed on the fingerprint sensor. For example, the capacitance type sensor 100 is provided with a detection electrode 103 that is finer than the unevenness of the fingerprint. Then, a two-dimensional image showing the unevenness of the fingerprint is created by the capacitance accumulated between the unevenness of the fingerprint and the detection electrode 103. For example, since the detected capacitance differs between the convex portion and the concave portion of the fingerprint, it is possible to create a two-dimensional image showing the unevenness of the fingerprint from the difference in the capacitance. Fingerprint information can be read from this two-dimensional image.

FIG. 1 is a cross-sectional view schematically showing the capacitance type sensor 100 according to the present embodiment.
The capacitance type sensor 100 according to the present embodiment includes a substrate 101, a detection electrode 103 provided on the substrate 101, a sealing film 105 for sealing the detection electrode 103, and a sealing film 105 on the surface of the sealing film 105. The surface coating film 109 formed on the surface coating film 109 is provided.
According to the present embodiment, the sealing film 105 that seals the detection electrode 103 is composed of a cured product of the present resin composition. Such a cured product has excellent dielectric properties. Therefore, the sensitivity of the capacitance type sensor 100 can be improved. Here, in the present embodiment, excellent dielectric properties mean, for example, that the relative permittivity and the dielectric loss tangent are high, and the capacitance is large.

In order to improve the sensitivity of the capacitance type sensor 100, the thickness D of the sealing film 105 on the substrate 101 (for example, a silicon chip) is, for example, 100 μm or less, more preferably 75 μm or less, still more preferably 50 μm or less. Particularly preferably, it is 30 μm or less.
According to this resin composition, even when the thickness D of the sealing film 105 is equal to or less than the above upper limit value, it is possible to reduce problems such as poor filling of the capacitance type sensor sealing resin composition. As a result, according to the present resin composition, it is possible to manufacture a capacitance type sensor having a thin sealing film 105 and having even higher sensitivity with a high yield.

The substrate 101 is, for example, a chip-shaped silicon substrate. The detection electrode 103 is formed of, for example, an Al film, and is arranged on the substrate 101 in a one-dimensional or two-dimensional array via an interlayer film 107. The interlayer film 107 is formed of, for example, SiO ₂ or the like.
The upper surface of the detection electrode 103 is covered with a sealing film 105. The detection electrode 103 is, for example, wire-bonded.

The capacitance type sensor 100 according to this embodiment can be manufactured based on known information. For example, it is manufactured as follows.
First, the interlayer film 107 is provided on the substrate 101, and then the detection electrode 103 is formed on the interlayer film 107. Next, the detection electrode 103 is hermetically sealed and molded with the present resin composition. Examples of the molding method include a compression molding method. Next, the present resin composition is thermoset to form a sealing film 105. As a result, the capacitance type sensor 100 according to the present embodiment can be obtained.

（式（１）中、Ａｒ ^１ はフェニレン基またはナフチレン基を表し、Ａｒ ^１ がナフチレン基の場合、グリシジルエーテル基はα位、β位のいずれに結合していてもよい。Ａｒ ^２ はフェニレン基、ビフェニレン基またはナフチレン基のうちのいずれか１つの基を表す。Ｒ _ａ およびＲ _ｂ は、それぞれ独立に炭素数１〜１０の炭化水素基を表す。ｇは０〜５の整数であり、ｈは０〜８の整数である。ｎ ^３ は重合度を表し、その平均値は１〜３である。）

（式（２）中、複数存在するＲ _ｃ は、それぞれ独立に水素原子または炭素数１〜４の炭化水素基を表す。ｎ ^５ は重合度を表し、その平均値は０〜４である。）

（式（３）中、複数存在するＲ _ｄ およびＲ _ｅ は、それぞれ独立に水素原子又は炭素数１〜４の炭化水素基を表す。ｎ ^６ は重合度を表し、その平均値は０〜４である。）
６． 当該静電容量型センサ封止用樹脂組成物中の前記エポキシ樹脂の含有量は、当該静電容量型センサ封止用樹脂組成物を１００質量％としたとき、２．０質量％以上３０質量％以下である、１．乃至５．のいずれか一つに記載の静電容量型センサ封止用樹脂組成物。
７． 前記硬化剤は、フェノール樹脂である、１．乃至６．のいずれか一つに記載の静電容量型センサ封止用樹脂組成物。
８． 前記フェノール樹脂は、トリフェニルメタン型フェノール樹脂、ビフェニルアラルキル型フェノール樹脂、及び、ナフトールアラルキル型フェノール樹脂からなる群より選択される１種以上である、７．に記載の静電容量型センサ封止用樹脂組成物。
９． 当該静電容量型センサ封止用樹脂組成物中の前記硬化剤の含有量は、当該静電容量型センサ封止用樹脂組成物を１００質量％としたとき、０．５質量％以上２０質量％以下である、１．乃至８．のいずれか一つに記載の静電容量型センサ封止用樹脂組成物。
１０． 前記充填剤が、シリカ、アルミナ、酸化チタンおよびチタン酸バリウムから選択される一種または二種以上を含む、１．乃至９．のいずれか一つに記載の静電容量型センサ封止用樹脂組成物。
１１． 当該静電容量型センサ封止用樹脂組成物全体に対する前記充填剤の含有量が、５０質量％以上９０質量％以下である、１．乃至１０．のいずれか一つに記載の静電容量型センサ封止用樹脂組成物。
１２． 前記充填剤の平均粒径Ｄ _５０ は、０．２μｍ以上８μｍ以下である、１．乃至１１．のいずれか一つに記載の静電容量型センサ封止用樹脂組成物。
１３． 当該静電容量型センサ封止用樹脂組成物は、着色剤を更に含む、１．乃至１２．のいずれか一つに記載の静電容量型センサ封止用樹脂組成物。
１４． 前記着色剤の含有量は、静電容量型センサ封止用樹脂組成物の全固形分を１００質量％としたとき、０．０１質量％以上０．１５質量％以下である、１３．に記載の静電容量型センサ封止用樹脂組成物。
１５． 前記静電容量型センサが静電容量型指紋センサである、１．乃至１４．のいずれか一つに記載の静電容量型センサ封止用樹脂組成物。
１６． 基板と、
前記基板上に設けられた検出電極と、
前記検出電極を封止し、かつ、１．乃至１５．のいずれか一つに記載の静電容量型センサ封止用樹脂組成物の硬化物により構成された封止膜と、
を備える静電容量型センサ。 The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.
Hereinafter, an example of the reference form is given.
1. 1. A resin composition for encapsulating a capacitance type sensor, which is used for forming a sealing film in a capacitance type sensor.
Epoxy resin and
Hardener and
Filler and
Including
For the cured product of the capacitance type sensor encapsulating resin composition, the value of the brightness L of the cured product calculated from the Hunter Lab color system using a spectrophotometer is 25 or more.
The chromaticity of the first test piece calculated from the Hunter Lab color system using a spectrophotometer for the first test piece made of the resin composition for encapsulating the capacitance type sensor obtained under the following condition 1. Let the value of b be b0
With respect to the second test piece made of the capacitance type sensor sealing resin composition obtained under the following condition 2, the chromaticity of the second test piece calculated from the Hunter Lab color system using a spectrophotometer. When the value of b is b1,
A resin composition for encapsulating a capacitance type sensor, wherein the value of Δb calculated by the formula b1-b0 is 0 or more and 30 or less.
(Condition 1: The cured product obtained by heat-treating the resin composition for encapsulating the capacitance type sensor at 175 ° C. for 3 minutes is used as the first test piece.)
(Condition 2: The cured product obtained by heat-treating the resin composition for encapsulating the capacitance type sensor at 175 ° C. for 3 minutes and then heat-treating at 175 ° C. for 4 hours is the second. Use as a test piece.)
2. For the first test piece obtained under the condition 1, the value of the brightness L of the first test piece calculated from the Hunter Lab color system using a spectrophotometer was set to L0.
With respect to the second test piece made of the capacitance type sensor sealing resin composition obtained under the above condition 2, the brightness L of the second test piece calculated from the Hunter Lab color system using a spectrophotometer. When the value of is L1,
1. The value of ΔLa calculated by the formula of L1-L0 is −3.5 or more and 5 or less. The resin composition for encapsulating a capacitive sensor according to the above.
3. 3. Regarding the third test piece made of the resin composition for encapsulating the capacitance type sensor obtained under the following condition 3, the brightness L of the third test piece calculated from the Hunter Lab color system using a spectrophotometer. When the value of is L2,
1. The value of ΔLb calculated by the formula of L2-L1 is -6 or more and 0 or less. Or 2. The resin composition for encapsulating a capacitive sensor according to the above.
(Condition 3: The cured product obtained by heat-treating the resin composition for encapsulating the capacitance type sensor at 175 ° C. for 3 minutes and then heat-treating at 175 ° C. for 8 hours is the third. Use as a test piece.)
4. For the cured product of the capacitance type sensor sealing resin composition, the value of the brightness L of the cured product calculated from the Hunter Lab color system using a spectrophotometer is 25 or more and 72 or less. 1. 1. To 3. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
5. 1. The filler comprises one or more selected from silica, alumina, titanium oxide and barium titanate. To 4. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
6. 1. The content of the filler in the entire resin composition for encapsulating the capacitance type sensor is 50% by mass or more and 90% by mass or less. To 5. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
7. The capacitance type sensor is a capacitance type fingerprint sensor. To 6. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
8. With the board
With the detection electrode provided on the substrate,
The detection electrode is sealed, and 1. To 7. A sealing film composed of a cured product of the resin composition for sealing a capacitance type sensor according to any one of the above.
Capacitive sensor with.
In addition, an example of the reference form will be added below.
1. 1. A resin composition for encapsulating a capacitance type sensor, which is used for forming a sealing film in a capacitance type sensor.
Epoxy resin and
Hardener and
Filler and
Including
For the cured product of the capacitance type sensor encapsulating resin composition, the value of the brightness L of the cured product calculated from the Hunter Lab color system using a spectrophotometer is 25 or more.
The chromaticity of the first test piece calculated from the Hunter Lab color system using a spectrophotometer for the first test piece made of the resin composition for encapsulating the capacitance type sensor obtained under the following condition 1. Let the value of b be b0
With respect to the second test piece made of the capacitance type sensor sealing resin composition obtained under the following condition 2, the chromaticity of the second test piece calculated from the Hunter Lab color system using a spectrophotometer. When the value of b is b1,
A resin composition for encapsulating a capacitance type sensor, wherein the value of Δb calculated by the formula b1-b0 is 0 or more and 30 or less.
(Condition 1: The cured product obtained by heat-treating the resin composition for encapsulating the capacitance type sensor at 175 ° C. for 3 minutes is used as the first test piece.)
(Condition 2: The cured product obtained by heat-treating the resin composition for encapsulating the capacitance type sensor at 175 ° C. for 3 minutes and then heat-treating at 175 ° C. for 4 hours is the second. Use as a test piece.)
2. For the first test piece obtained under the condition 1, the value of the brightness L of the first test piece calculated from the Hunter Lab color system using a spectrophotometer was set to L0.
With respect to the second test piece made of the capacitance type sensor sealing resin composition obtained under the above condition 2, the brightness L of the second test piece calculated from the Hunter Lab color system using a spectrophotometer. When the value of is L1,
1. The value of ΔLa calculated by the formula of L1-L0 is −3.5 or more and 5 or less. The resin composition for encapsulating a capacitive sensor according to the above.
3. 3. Regarding the third test piece made of the resin composition for encapsulating the capacitance type sensor obtained under the following condition 3, the brightness L of the third test piece calculated from the Hunter Lab color system using a spectrophotometer. When the value of is L2,
1. The value of ΔLb calculated by the formula of L2-L1 is -6 or more and 0 or less. Or 2. The resin composition for encapsulating a capacitive sensor according to the above.
(Condition 3: The cured product obtained by heat-treating the resin composition for encapsulating the capacitance type sensor at 175 ° C. for 3 minutes and then heat-treating at 175 ° C. for 8 hours is the third. Use as a test piece.)
4. For the cured product of the capacitance type sensor sealing resin composition, the value of the brightness L of the cured product calculated from the Hunter Lab color system using a spectrophotometer is 25 or more and 72 or less. 1. 1. To 3. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
5. The epoxy resin includes an epoxy resin containing a structural unit represented by the following formula (1), an epoxy resin containing a structural unit represented by the following formula (2), and a structural unit represented by the following formula (3). 1. Including one or more selected from the group consisting of epoxy resins containing. To 4. The resin composition for encapsulating a capacitance type sensor according to any one of the above.

(In the formula (1), Ar ¹ represents a phenylene group or a naphthylene group, and when Ar ¹ is a naphthylene group, the glycidyl ether group may be bonded to either the α-position or the β-position ^{. Ar 2} is a phenylene group. , A group of any one of a biphenylene group and a naphthalene group. _Ra and R _b each independently represent a hydrocarbon group having 1 to 10 carbon atoms. G is an integer of 0 to 5, and h. Is an integer from 0 to 8. n ³ represents the degree of polymerization, and the average value thereof is 1 to 3.)

(In the formula (2), a plurality of R _cs independently represent a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. N ⁵ represents the degree of polymerization, and the average value thereof is 0 to 4. )

(In the formula (3), a plurality of R _d and _Re each independently represent a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. N ⁶ represents the degree of polymerization, and the average value thereof is 0 to 4. Is.)
6. The content of the epoxy resin in the capacitance type sensor sealing resin composition is 2.0% by mass or more and 30% by mass when the capacitance type sensor sealing resin composition is 100% by mass. % Or less, 1. To 5. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
7. The curing agent is a phenol resin. To 6. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
8. The phenol resin is one or more selected from the group consisting of a triphenylmethane type phenol resin, a biphenyl aralkyl type phenol resin, and a naphthol aralkyl type phenol resin. The resin composition for encapsulating a capacitive sensor according to the above.
9. The content of the curing agent in the capacitance type sensor sealing resin composition is 0.5% by mass or more and 20% by mass when the capacitance type sensor sealing resin composition is 100% by mass. % Or less, 1. ~ 8. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
10. 1. The filler comprises one or more selected from silica, alumina, titanium oxide and barium titanate. ~ 9. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
11. 1. The content of the filler in the entire resin composition for encapsulating the capacitance type sensor is 50% by mass or more and 90% by mass or less. To 10. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
12. The average particle size D ₅₀ of the filler is 0.2 μm or more and 8 μm or less. To 11. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
13. The capacitance type sensor encapsulation resin composition further contains a colorant. To 12. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
14. The content of the colorant is 0.01% by mass or more and 0.15% by mass or less when the total solid content of the resin composition for encapsulating the capacitive sensor is 100% by mass. The resin composition for encapsulating a capacitive sensor according to the above.
15. The capacitance type sensor is a capacitance type fingerprint sensor. To 14. The resin composition for encapsulating a capacitance type sensor according to any one of the above.
16. With the board
With the detection electrode provided on the substrate,
The detection electrode is sealed, and 1. To 15. A sealing film composed of a cured product of the resin composition for sealing a capacitance type sensor according to any one of the above.
Capacitive sensor with.

Hereinafter, the present embodiment will be described in detail with reference to Examples and Comparative Examples. The present embodiment is not limited to the description of these examples.

(Preparation of Resin Composition for Capacitive Sensor Encapsulation)
First, each raw material blended according to Table 1 was kneaded at 110 ° C. for 7 minutes using a twin-screw kneading extruder. Then, the obtained kneaded product was degassed and cooled, and then pulverized with a pulverizer to obtain granules. In Examples 1 to 4 and Comparative Example 1, the granules thus obtained were further sieved to obtain a granular resin composition. Details of each component in Table 1 are as follows. The unit in Table 1 is mass%.

The raw material components used in each Example and each Comparative Example are shown below.

(Epoxy resin)
-Epoxy resin 1: Biphenyl type epoxy resin containing the structural unit represented by the above formula (2) (manufactured by Mitsubishi Chemical Corporation, YX4000K)
-Epoxy resin 2: A biphenyl aralkyl type epoxy resin containing a structural unit represented by the above formula (1), where Ar ¹ is a phenylene group and Ar ² is a biphenylene group (manufactured by Nippon Kayaku Co., Ltd., NC3000L).

(Hardener)
-Curing agent 1: Triphenylmethane type phenol resin modified with formaldehyde (manufactured by Air Water Inc., HE910-20)
-Curing agent 2: Biphenyl aralkyl type phenol resin (manufactured by Nippon Kayaku Co., Ltd., GPH-65)
-Curing agent 3: Naphthol aralkyl type phenol resin (manufactured by Toto Kasei Co., Ltd., SN-485)

(Curing accelerator)
-Curing accelerator 1: tetraphenylphosphonium / bisphenol S salt-Curing accelerator 2: tetraphenylphosphonium / 2,3-dihydroxynaphthalene salt

(filler)
・ Filler 1: Spherical alumina (manufactured by Nippon Steel Materials Co., Ltd., AX3-10R, specific gravity 4, average particle size D ₅₀ : 3 μm)
-Paper 2: Spherical alumina (manufactured by Nippon Steel Materials Co., Ltd., AX3-15R, specific gravity 4, average particle size D ₅₀ : 3.9 μm)
Filler 3: Fused spherical silica (manufactured by Admatex, SC220G-SQ, average particle size D ₅₀ : 0.5 μm)

(Other ingredients)
-Coupling agent: Phenylaminopropyltrimethoxysilane (manufactured by Toray Dow Corning, CF4083)
-Release agent: Stearyl alcohol-modified olefin / maleic acid copolymer (manufactured by Air Water Inc., half ester)
-Colorant: Carbon black (manufactured by Tokai Carbon Co., Ltd., ERS-2001)
-Ion scavenger: Hydrotalcite (manufactured by Toagosei Co., Ltd., IXE-700F)
-Low stress agent: Acrylonitrile-butadiene rubber (manufactured by PTI Japan, CTBN1008SP)

The following evaluations and measurements were carried out using the obtained resin composition. The cured products of the resin compositions of Examples 1 and 2 and Comparative Example 1 had a hue generally called white at the stage immediately after curing. The cured products of the resin compositions of Examples 3 and 4 had a hue generally called gray in the stage immediately after curing.

-Brightness L, chromaticity a, and chromaticity b of the cured product: First, a test piece composed of the cured product of the obtained resin composition was prepared. Specifically, each of the obtained resin compositions is heat-treated at 175 ° C. for 3 minutes to obtain a cured product (in the table below, “heat treatment time: 0 hours”). A cured product obtained by heat-treating at 175 ° C. for 3 minutes and then heat-treating at 175 ° C. for 2 hours (in the table below, it is indicated as "heat treatment time: 2 hours"), 175 ° C. for 3 minutes. After the heat treatment under the conditions of 175 ° C. for 4 hours, the cured product (indicated as "heat treatment time: 4 hours" in the table below) was heat-treated at 175 ° C. for 3 minutes. After that, a cured product obtained by heat treatment at 175 ° C. for 6 hours (in the table below, it is indicated as "heat treatment time: 6 hours"), after heat treatment under the conditions of 175 ° C. for 3 minutes, 175 ° C. A cured product obtained by heat treatment for 8 hours (indicated as "heat treatment time: 8 hours" in the table below) was prepared.
Next, using Color Reader CR-13 manufactured by Konica Minolta Sensing Co., Ltd., the values of lightness L, chromaticity a, and chromaticity b were measured for each test piece made of a cured product of the obtained resin composition. The measurement conditions were set to measurement mode: reflection, number of measurements: n = 3 times.
The larger the value of the chromaticity a, the redder the color of the cured product. Further, the larger the value of the chromaticity b, the yellower the color of the cured product. Further, the larger the value of the lightness L, the darker the cured product. As a result of the evaluation, it was confirmed that the cured product of the resin composition of Comparative Example 1 had a reddish-black color as compared with the cured product of the example.

-Color development of the surface coating film provided on the capacitive fingerprint sensor: The capacitive fingerprint sensor shown in FIG. 1 was produced using the obtained resin composition. Next, the surface of the sealing film 105 provided on the obtained capacitive fingerprint sensor was painted with a white paint. With respect to the capacitance type fingerprint sensor thus obtained, the color-developing property of the surface coating film 109 was visually observed. Next, the capacitive fingerprint sensor was heat-treated to accelerate the change in color development with time, and the color development was visually evaluated. The evaluation criteria are as follows.
⊚: It was confirmed that the color of the sealing film 105 did not show through before the heat treatment, the color developing property was hardly deteriorated even when the heat treatment was applied, and the surface coating film had a practically acceptable level of color developing property. ..
◯: It was confirmed that the color of the sealing film 105 did not show through before the heat treatment, and the color-developing property gradually decreased with each heat treatment, but the surface coating film had a practically acceptable level of color-developing property. rice field.
X: The color of the sealing film 105 was not transparent before the heat treatment, but it was confirmed that the surface coating film showed a practically problematic level of color development as the color development decreased with each heat treatment. rice field.

As shown in Table 1 above, in the capacitance type fingerprint sensor provided with the sealing film 105 produced by using the resin compositions of Examples 1 to 4, the surface of the sealing film 105 is surfaced with a white paint. It was confirmed that even when the coating film 109 was formed, the sealing film 105 exhibited good color development without the color being transparent through the surface coating film 109.

100 Capacitive sensor 101 Substrate 103 Detection electrode 105 Encapsulating film 107 Interlayer film 109 Surface coating film

Claims (14)

A resin composition for encapsulating a capacitance type sensor, which is used for forming a sealing film in a capacitance type sensor.
Epoxy resin and
Hardener and
Filler and
Including
The content of the epoxy resin is 6.2% by mass or more in 100% by mass of the solid content of the resin composition for encapsulating the capacitance type sensor.
The content of the curing agent is 5.8% by mass or less in 100% by mass of the solid content of the resin composition for encapsulating the capacitance type sensor.
The curing agent contains a biphenyl aralkyl type phenol resin.
For the cured product of the capacitance type sensor encapsulating resin composition, the value of the brightness L of the cured product calculated from the Hunter Lab color system using a spectrophotometer is 25 or more.
The chromaticity of the first test piece calculated from the Hunter Lab color system using a spectrophotometer for the first test piece made of the resin composition for encapsulating the capacitance type sensor obtained under the following condition 1. Let the value of b be b0
With respect to the second test piece made of the capacitance type sensor sealing resin composition obtained under the following condition 2, the chromaticity of the second test piece calculated from the Hunter Lab color system using a spectrophotometer. When the value of b is b1,
A resin composition for encapsulating a capacitance type sensor, wherein the value of Δb calculated by the formula b1-b0 is 0 or more and 30 or less.
(Condition 1: The cured product obtained by heat-treating the resin composition for encapsulating the capacitance type sensor at 175 ° C. for 3 minutes is used as the first test piece.)
(Condition 2: The cured product obtained by heat-treating the resin composition for encapsulating the capacitance type sensor at 175 ° C. for 3 minutes and then heat-treating at 175 ° C. for 4 hours is the second. Use as a test piece.) For the first test piece obtained under the condition 1, the value of the brightness L of the first test piece calculated from the Hunter Lab color system using a spectrophotometer was set to L0.
With respect to the second test piece made of the capacitance type sensor sealing resin composition obtained under the above condition 2, the brightness L of the second test piece calculated from the Hunter Lab color system using a spectrophotometer. When the value of is L1,
The resin composition for encapsulating a capacitance type sensor according to claim 1, wherein the value of ΔLa calculated by the formula of L1-L0 is −3.5 or more and 5 or less. Regarding the third test piece made of the resin composition for encapsulating the capacitance type sensor obtained under the following condition 3, the brightness L of the third test piece calculated from the Hunter Lab color system using a spectrophotometer. When the value of is L2,
The resin composition for encapsulating a capacitance type sensor according to claim 1 or 2, wherein the value of ΔLb calculated by the formula of L2-L1 is −6 or more and 0 or less.
(Condition 3: The cured product obtained by heat-treating the resin composition for encapsulating the capacitance type sensor at 175 ° C. for 3 minutes and then heat-treating at 175 ° C. for 8 hours is the third. Use as a test piece.) For the cured product of the capacitance type sensor sealing resin composition, the value of the brightness L of the cured product calculated from the Hunter Lab color system using a spectrocolorimeter is 25 or more and 72 or less. The resin composition for encapsulating a capacitance type sensor according to any one of claims 1 to 3. The epoxy resin includes an epoxy resin containing a structural unit represented by the following formula (1), an epoxy resin containing a structural unit represented by the following formula (2), and a structural unit represented by the following formula (3). The resin composition for encapsulating a capacitance type sensor according to any one of claims 1 to 4, which comprises at least one selected from the group consisting of epoxy resins containing.

(In the formula (1), Ar ¹ represents a phenylene group or a naphthylene group, and when Ar ¹ is a naphthylene group, the glycidyl ether group may be bonded to either the α-position or the β-position ^{. Ar 2} is a phenylene group. , A group of any one of a biphenylene group and a naphthalene group. _Ra and R _b each independently represent a hydrocarbon group having 1 to 10 carbon atoms. G is an integer of 0 to 5, and h. Is an integer from 0 to 8. n ³ represents the degree of polymerization, and the average value thereof is 1 to 3.)

(In the formula (2), a plurality of R _cs independently represent a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. N ⁵ represents the degree of polymerization, and the average value thereof is 0 to 4. )

(In the formula (3), a plurality of R _d and _Re each independently represent a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. N ⁶ represents the degree of polymerization, and the average value thereof is 0 to 4. Is.) The content of the epoxy resin of the capacitive sensor encapsulating resin composition, can and the capacitive sensor encapsulating resin composition was 100% by mass, is 3 0 wt% or less , The resin composition for encapsulating a capacitance type sensor according to any one of claims 1 to 5. The content of the curing agent of the capacitive sensor encapsulating resin composition, when the electrostatic capacity-type sensor encapsulating resin composition as 100 wt%, on a 0.5% by mass or The resin composition for encapsulating a capacitance type sensor according to any one of claims 1 to 6. The resin composition for encapsulating a capacitive sensor according to any one of claims 1 to 7 , wherein the filler contains one or more selected from silica, alumina, titanium oxide and barium titanate. thing. The capacitance type according to any one of claims 1 to 8 , wherein the content of the filler in the entire resin composition for encapsulating the capacitance type sensor is 50% by mass or more and 90% by mass or less. Resin composition for sensor encapsulation. The resin composition for encapsulating a capacitive sensor according to any one of claims 1 to 9 , wherein the average particle size D ₅₀ of the filler is 0.2 μm or more and 8 μm or less. The resin composition for encapsulating a capacitance type sensor according to any one of claims 1 to 10, further comprising a colorant. The content of the coloring agent, when the total solids of the capacitive sensor encapsulating resin composition as 100 mass%, 0.15 mass% 0.01 mass% or more, in claim 11 The resin composition for encapsulating a capacitive sensor according to the above. The resin composition for encapsulating a capacitance type sensor according to any one of claims 1 to 12 , wherein the capacitance type sensor is a capacitance type fingerprint sensor. With the board
With the detection electrode provided on the substrate,
A sealing film that seals the detection electrode and is composed of a cured product of the resin composition for sealing a capacitance type sensor according to any one of claims 1 to 13.
Capacitive sensor with.

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