Photosensitive resin composition, overcoat film, fingerprint sensor, and display device

Abstract

A photosensitive resin composition is a photosensitive resin composition containing (1) an alkali-soluble resin, (2) a polymerizable compound, and (3) a photopolymerization initiator, the double bond equivalent of the above (1) alkali-soluble resin is 2000 or more and 5000 or less, and the transmittance of a resin film having a film thickness of 9 μm obtained from the photosensitive resin composition to light having a wavelength of 380 to 780 nm is 90 to 100% in the entire range of the wavelength of 380 to 780 nm. A photosensitive resin composition suitable for producing an overcoat film of a display device provided with a fingerprint sensor is provided.

Description

TECHNICAL FIELD

[0001] The present application relates to a photosensitive resin composition suitable for an overcoat film for a fingerprint sensor or the like, and a resin film, an overcoat film, a fingerprint sensor, and a display device each using the photosensitive resin composition. BACKGROUND

[0002] In recent years, display devices provided with a fingerprint sensor are widely used in order to impart security performance. For such a display device provided with a fingerprint sensor, in order to improve design freedom and production cost, an overcoat film having a relatively thick film thickness is required as a function of imparting excellent optical characteristics to a display portion and adjusting an optical path length for removing noise of a sensor while maintaining high precision.

[0003] On the other hand, conventional photosensitive resin compositions have been mainly applied to uses such as resin films for color filters, and have been designed on the premise that a strong cured film is obtained even for a thin film having a thickness of about 2 μm. In order to obtain a strong photopolymerization cured film with such a film thickness, a resin that is a main agent of the conventional photosensitive resin composition is preferably selected to be an alkali-soluble resin having a double bond equivalent of 2000 or less, such as that described in Patent Literature 1.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 2010-145719 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] However, in a case where an overcoat film having a thick film thickness is formed using such a conventional photosensitive resin composition, there is a problem that the substrate is bent in a manufacturing process due to film stress of the overcoat film, and process yield is deteriorated. In addition, the conventional photosensitive resin composition has a problem that, when an overcoat film having a thick film is produced, yellow coloring is caused by a photopolymerization initiator or the like contained therein, although slightly, and thus display performance of a display device is deteriorated.

[0009] Therefore, in an overcoat film used for a display device provided with a fingerprint sensor, a thermosetting resin composition is used instead of a photosensitive resin composition, but in a case where a thermosetting resin composition is used, there is a problem that a fine pattern obtained by using a photolithography method using a photosensitive resin composition cannot be processed, and the overcoat film cannot be applied to a high-performance fingerprint sensor.

[0010] Therefore, in the present application, a photosensitive resin composition capable of forming an overcoat film having low film stress even for a thick film, which is suitable for producing an overcoat film for a display device provided with a high-performance fingerprint sensor, is provided as an object.

[0011] Method for solving the problem

[0012] That is, the present application is a photosensitive resin composition comprising (1) an alkali-soluble resin, (2) a polymerizable compound, and (3) a photopolymerization initiator, the double bond equivalent of the above (1) alkali-soluble resin being 2000 or more and 5000 or less, the transmittance of a resin film having a thickness of 9 μm obtained from the above photosensitive resin composition to light having a wavelength of 380 to 780 nm being 90 to 100% in the entire range of the wavelength of 380 to 780 nm.

[0013] Further, the present application is a resin film obtained by curing the above photosensitive resin composition.

[0014] Further, another aspect of the present application is an overcoat film for a fingerprint sensor, which is an overcoat film for a fingerprint sensor having a thickness of 4 μm or more and 15 μm or less, the transmittance of the overcoat film per 9 μm thickness to light having a wavelength of 380 to 780 nm being 90 to 100% in the entire range of the wavelength of 380 to 780 nm.

[0015] Further, the present application is a fingerprint sensor having the above overcoat film.

[0016] Further, the present application is a display device provided with the above fingerprint sensor.

[0017] Effects of the invention

[0018] According to the photosensitive resin composition of the present application, it is possible to provide a photosensitive resin composition which can form an overcoat film having weak cross-linking which exhibits softness after light curing in a thick film, and which is low in stress even in a thick film. Further, the transmittance to light having a wavelength of 380 to 780 nm when a resin film is formed to have a thickness of 9 μm is 90 to 100%, so that even in the case where a film having a thick thickness is formed, coloring is not substantially exhibited, and a film which is very high in visibility and is almost colorless and transparent can be obtained. Therefore, even in the case where it is applied to an overcoat film used for a display device provided with a fingerprint sensor, it is possible to maintain the display performance of the display device.

[0019] Further, the fingerprint sensor and the display device of the present application have an effect of improving the problems of deterioration of process yield in the manufacturing process and deterioration of display performance of the display device by having an overcoat film formed using the above resin composition. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1As an example of a schematic cross-sectional view of a case where a fine pattern having a pore diameter of 40 μm is formed in a resin film of the present application having a film thickness of 9.0 μm, (a) shows a case where no residual film is formed, and (b) shows a case where a residual film is formed.

[0021] Figure 2 As an example of a schematic perspective view of a fingerprint sensor in which the overcoat film of the present application is formed on a color filter substrate. DETAILED DESCRIPTION

[0022] Hereinafter, the photosensitive resin composition of the present application is described in detail. The photosensitive resin composition of the present application is a photosensitive resin composition comprising (1) an alkali-soluble resin, (2) a polymerizable compound, and (3) a photopolymerization initiator, the double bond equivalent of the above-mentioned (1) alkali-soluble resin being 2000 or more and 5000 or less, and the transmittance of a resin film having a film thickness of 9 μm obtained from the above-mentioned photosensitive resin composition with respect to light having a wavelength of 380 to 780 nm being 90 to 100% in the entire range of the wavelength of 380 to 780 nm.

[0023] The (1) alkali-soluble resin in the present application means a resin comprising a unit derived from an unsaturated carboxylic acid as a polymerization unit. As the unsaturated carboxylic acid, a monocarboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, or vinylacetic acid, or a dicarboxylic acid such as itaconic acid, maleic acid, or fumaric acid, or an anhydride thereof can be mentioned. Particularly preferably, a unit derived from acrylic acid or methacrylic acid is contained.

[0024] The double bond equivalent in the present application is a value obtained by dividing the weight average molecular weight of the above-mentioned alkali-soluble resin by the number of double bonds in one molecule of the above-mentioned alkali-soluble resin. In general, the double bond equivalent of the alkali-soluble resin of a photosensitive resin composition is about 100 to 1000, and if the double bond equivalent is higher than this, the cross-linking density of the double bond portion becomes less, and the photocuring tends to become insufficient. However, in the present application, an alkali-soluble resin having a double bond equivalent higher than this is intentionally selected, and a resin film which can be applied to an overcoat film of a fingerprint sensor can be formed.

[0025] If a cross-linking structure is formed in the alkali-soluble resin by utilizing the properties of the double bond, even if stress is applied to the polymer main chain, the polymer main chain does not separate, and the deformation of the polymer main chain corresponding to the stress is efficiently performed, and the entropic elasticity is improved. The resin film composed of the polymer main chain whose entropic elasticity is improved has flexibility, and the film stress is relaxed. However, if the double bonds in the alkali-soluble resin are too many, the cross-linking density is too high, the obtained resin film becomes hard, and the flexibility is impaired.

[0026] On the other hand, in order to be able to apply the photosensitive resin composition to the overcoat film of the fingerprint sensor and the like as described above, it is necessary to form a thick film. Specifically, it is necessary to obtain an overcoat film having a thickness of about 9 μm on average. When the overcoat film having such a film thickness is formed, it is necessary to have the crosslinking structure in which the entropic elasticity is maximally exhibited.

[0027] The present inventors and others have conducted intensive studies, and as a result, it has been found that if an alkali-soluble resin having a double bond equivalent of 2000 or more and 5000 or less is selected, such an effect can be obtained. Further, if the viewpoint of the photosensitivity improvement at the time of development later is also taken into consideration, the double bond equivalent is more preferably 2500 or more and 4000 or less.

[0028] The transmittance of the resin film having a film thickness of 9 μm for light having a wavelength of 380 to 780 nm can be measured as follows. A resin film having a film thickness of 9 μm is formed on a substrate by the conditions described in the Examples described later. In the case where a plastic plate is used as the substrate, the transmittance of light is measured by following the procedure of JIS K 7361-1 (ISO 13468-1), and in the case where a glass plate is used as the substrate, the transmittance of light is measured by following the procedure of JIS R 3106. The method itself is the same in that from the vertical direction of the resin film surface formed on the transparent substrate, a light beam nearly parallel is made to exit from the exit slit of a spectrophotometer, and the transmitted light is received with an integrating sphere. The transmittance of the substrate on which the resin film is formed and the transmittance of the substrate on which the resin film is not formed are measured in this way, and by subtracting the transmittance of the substrate on which the resin film is not formed from the transmittance of the substrate on which the resin film is formed, the transmittance of the resin film can be calculated. In addition, the transmittance in the present invention is the total light transmittance.

[0029] In the case where the substrate is not determined, the transmittance of the resin film having a film thickness of 9 μm is preferably measured using the photosensitive resin composition as follows. Specifically, the solid content of the photosensitive resin composition of the present invention is diluted with a solvent to (10000 / 9) times, and this is filled in a spectrophotometer cell having an optical path length of 1 cm to measure. According to the Lambert-Beer law, the concentration of the solute is in inverse proportion to the optical path length, and therefore the transmittance measured by this method corresponds to the transmittance of the resin film having a film thickness of 9 μm. In addition, the solid content is the entire component of the photosensitive resin composition excluding the solvent. The values of the transmittance in any of the above-described schemes are the same as the transmittance of the resin film.

[0030] Further, in order to achieve a low film stress value, the photosensitive resin composition of the present invention preferably has a photosensitive resin composition in which the photosensitive resin composition is cured at an exposure amount of 70 mJ / cm 2The volume shrinkage of the photosensitive resin composition before and after curing under the conditions of 70 mJ / cm2is 8% or less. This is because the overcoat film made of the photosensitive resin composition having such a low volume shrinkage has a small shrinkage in the film direction (i.e., the left-right direction of the paper in Figure 1

[0031] In addition, if the difference between the expansion rates of the overcoat film and the substrate is small, the peeling strain from the substrate is reduced, and the adhesion to the substrate is improved. As a result, the peeling of the overcoat film from the substrate is also reduced in the development process when the overcoat film is patterned.

[0032] In addition, in the present application, the volume shrinkage in the curing reaction can be calculated by measuring the densities of the photosensitive resin composition before and after curing, using the following equation. For example, if the density of the photosensitive resin composition before curing is 1.0 g / cm 3 , and the density of the resin cured product after curing of the photosensitive resin composition is 1.09 g / cm 3 or 1.10 g / cm 3 , the volume shrinkage (%) becomes about 8% or about 9%, respectively.

[0033] Volume shrinkage (%) = (1 - (density of the photosensitive resin composition before curing / density of the resin cured product after curing)) x 100.

[0034] Here, the photosensitive resin composition before curing is a photosensitive resin composition composed of a solid substance after the solvent is scattered using a reduced-pressure drier. In addition, the resin cured product after curing is a substance in which the photosensitive resin composition before curing is exposed to ultraviolet rays under the conditions of an exposure amount of 70 mJ / cm 2 . The densities of the photosensitive resin composition before curing and the resin cured product after curing can be measured by the water displacement method (Archimedes method). More specifically, for example, the specific gravity measuring kit AD-1653 manufactured by A and D Company Limited can be used, distilled water is used as the displacement liquid, and the density (p) is calculated using the following equation.

[0035] p = A / (A-B) x (p0-d) + d

[0036] In the above equation, A represents the mass of the solid substance in the air, B represents the weight of the displacement liquid (distilled water) in the volume, p0represents the density of the displacement liquid (distilled water) at the measurement temperature, and d represents the density of the air (0.001 g / cm 3 ).

[0037] ​In order to achieve a low volume shrinkage, for example, as the (1) alkali-soluble resin, it is preferable to select a resin having a double bond equivalent of 2000 or more and 5000 or less, and containing a unit having a skeleton derived from acrylic acid or methacrylic acid, and a substituted or unsubstituted alkyl group having a carbon content of 5 or more. Specifically, it is preferable to use a resin containing a unit having a tricyclodecane skeleton, a dicyclopentene skeleton, such as tricyclodecyl (meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyl oxylethyl (meth)acrylate, and the like.

[0038] Further, in order to improve the sensitivity at the time of exposure and development for forming a fine pattern, the (1) alkali-soluble resin preferably has a vinyl group, an allyl group, an acryloyl group, or a methacryloyl group, or the like, as an olefinic unsaturated group in the side chain. As a method for introducing an olefinic unsaturated group into the side chain of the alkali-soluble resin, a method in which an olefinic unsaturated compound having an epoxy group or acrylic acid or methacryloyl chloride is subjected to an addition reaction with a carboxyl group or a hydroxyl group possessed by the alkali-soluble resin can be cited.

[0039] Here, as the olefinic unsaturated compound having an epoxy group, an olefinic unsaturated compound having a glycidyl group or an alicyclic epoxy group can be cited. As the olefinic unsaturated group, an acryloyl group or a methacryloyl group is preferable. Specifically, glycidyl acrylate, glycidyl (meth)acrylate, allyl glycidyl ether, α-ethyl glycidyl acrylate, crotonoyl glycidyl ether, (iso)crotonic acid glycidyl ether, N-(3,5-dimethyl-4-glycidyl)benzyl acrylamide, or (3,4-epoxycyclohexyl)methyl (meth)acrylate can be cited.

[0040] Further, in order to obtain a moderate alkali developability, the acid value of the (1) alkali-soluble resin is preferably 20 to 200 (mgKOH / g), and more preferably 30 to 150 (mgKOH / g).

[0041] The content of the alkali-soluble resin in the photosensitive resin composition is preferably 30% by mass or more and 70% by mass or less in the solid content, and more preferably 35% by mass or more and 65% by mass or less in the solid content. By containing 30% by mass or more in the solid content, the film stress of the overcoat film is moderated. On the other hand, by containing 70% by mass or less in the solid content, the solubility at the time of development of the overcoat film, that is, the pattern forming properties can be improved. In addition, the solid content in the present application means all of the components included in the photosensitive resin composition, excluding the solvent.

[0042] Further, the photosensitive resin composition of the present application contains (2) a polymerizable compound. The (2) polymerizable compound is a compound having an ethylenic unsaturated double bond. The above-mentioned (1) alkali-soluble resin has a relatively high molecular weight, and the development solubility, i.e., the pattern forming property at the time of forming a fine pattern, is slightly poor. Further, since it is formed as a thick film, even if an ethylenic unsaturated group is introduced into a side chain, or the acid value and the solid content amount are optimized, a residual film (development residue) is easily left. By containing the (2) polymerizable compound, it is possible to reduce the residual film.

[0043] As the polymerizable compound, for example, bisphenol A diglycidyl ether (meth)acrylate, poly(meth)acrylate urethane, modified bisphenol A epoxy (meth)acrylate, adipic acid 1,6-hexanediol (meth)acrylate, phthalic anhydride oxypropylene (meth)acrylate, diethylene glycol trimellitate (meth)acrylate, rosin-modified epoxy di(meth)acrylate, alkyd-modified (meth)acrylate, and the like oligomers, tripropyleneglycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetra(trimethylolpropane) tri(meth)acrylate, pentaerythritol tri(meth)acrylate, 1,3,5-triacryloylhexahydro-1,3,5-triazine, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, diphenyloxyethanol fluorene diacrylate, dicyclopentane dicyclopentenyl diacrylate, or an alkyl-modified, alkyl ether-modified, alkyl ester-modified, or the like thereof can be mentioned. Two or more of them can be contained. From the viewpoint of more effectively performing internal curing and more suppressing particle defects, it is preferable to have three or more ethylenic unsaturated bonds in one molecule, and more preferably five or more ethylenic unsaturated bonds in one molecule.

[0044] It is preferable that the (2) polymerizable compound be a polymerizable compound containing a hydroxyl group. The affinity of a hydroxyl group to an alkali developer is high, and the solubility of a polymerizable compound having a hydroxyl group in an alkali developer becomes very high. Therefore, by the photosensitive resin composition containing a polymerizable compound containing a hydroxyl group in the development step, the alkali developer easily penetrates into the details of the obtained resin-coated film, and it is possible to reduce a residual film. As a result, the pattern forming property of the resin-coated film is improved, and it is possible to manufacture a high-performance fingerprint sensor.

[0045] As the polymerizable compound containing a hydroxyl group and having three or more ethylenic unsaturated double bonds in one molecule, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, and the like can be mentioned. Pentaerythritol triacrylate is particularly preferable.

[0046] The content of the (2) polymerizable compound in the photosensitive resin composition is preferably 25% by mass or more and 65% by mass or less in the solid content, and more preferably 30% by mass or more and 60% by mass or less in the solid content. By containing 25% by mass or more of the (2) polymerizable compound, the solubility of the alkali-soluble resin can be increased by the penetration of the alkaline developer into the fine details. On the other hand, by making the polymerizable compound 70% by mass or less, the curing shrinkage of the excess double bonds is suppressed, and the relaxation of the film stress of the overcoat film is maintained.

[0047] Further, the photosensitive resin composition of the present application contains (3) a photopolymerization initiator. This is to become an opportunity for the reaction of the unsaturated double bonds present in the above-mentioned (1) alkali-soluble resin and (2) polymerizable compound, and to prevent adverse effects caused by unreacted double bonds. If the double bond equivalent of the (1) alkali-soluble resin is 2000 or more as in the present application, the photocuring tends to become insufficient as described in Patent Document 1. If the residues of the double bonds remain in a large amount in a state where the photocuring of the resin film is insufficient, not only is the effect of the relaxation of the film stress not obtained, but also the problem of the decrease in the stability over time due to the adverse effects of the residues occurs.

[0048] Further, the photosensitive resin composition of the present application, since a thick film must be formed, the degree of photocuring at the surface and the deep part of the film deviates (i.e., the proportion of the residues of the double bonds deviates), and the development failure tends to occur. Therefore, in order not to occur such a situation, it is preferable that the photopolymerization initiator reaches not only the surface but also uniformly reaches the deep part. As the photopolymerization initiator having such a function, a photobleaching type photopolymerization initiator can be cited. The so-called photobleaching type photopolymerization initiator is a photopolymerization initiator in which the light absorption decreases due to the cleavage of the double bond as the reaction proceeds.

[0049] Specifically, there are, for example, monoacylphosphine oxide-based photopolymerization initiators such as benzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,3,5,6-tetramethylbenzoyl-diphenylphosphine oxide, 3,4-dimethylbenzoyl-diphenylphosphine oxide, and the like; bisacylphosphine oxide-based photopolymerization initiators such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)2,4,4-trimethyl-pentylphosphine oxide, bis(2,6-dimethylbenzoyl)ethylphosphine oxide, and the like; metallocene (titanocene)-based photopolymerization initiators such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium, and the like; polysilane-based photopolymerization initiators such as phenylmethylpolysilane, diphenylpolysilane, phenylpolysilane, and the like; O-acyloxime-based initiators such as ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime), and the like. These photopolymerization initiators are commercially available, and it is preferable to use, for example, "Irgacure 819", "Irgacure 784", "DAROCUR TPO", "NCI-930", and the like.

[0050] If the photopolymerization initiator is excessively increased, the photopolymerization initiator is sometimes precipitated as an impurity. The content of the photopolymerization initiator is preferably 1% by mass or more and 10% by mass or less in the solid content. By the content of the photopolymerization initiator being 1% by mass or more, development failure is less likely to occur. On the other hand, by the content of the photopolymerization initiator being 10% by mass or less, the amount of impurities precipitated from the overcoat film is small, and display failure of the display device can be suppressed.

[0051] The photosensitive resin composition of the present application has a transmittance of 90 to 100% in the entire range of wavelengths of 380 to 780 nm when a resin film having a film thickness of 9 μm is formed. A film having a transmittance of 90% or more in the wavelengths of 380 to 780 nm becomes a film which is substantially not colored and colorless transparent by visual observation, and even in the case of being applied to an overcoat film used for a display device provided with a high-performance fingerprint sensor, the display performance of the display device can be maintained. Therefore, the photosensitive resin composition of the present application can be suitably used for a display device use provided with a fingerprint sensor.

[0052] In addition, when the thickness of the resin film is thinner than 9 μm or thicker, the transmittance is converted to that of 9 μm thickness in accordance with the Lambert-Beer law as follows. For example, when the thickness of the resin film is 4.5 μm and the transmittance at this thickness is 97.0%, the transmittance converted to that of 9 μm thickness becomes 94.1%. On the other hand, when the thickness of the resin film is 13.5 μm and the transmittance at this thickness is 86.1%, the transmittance converted to that of 9 μm thickness becomes 91.0%.

[0053] log(l / T) ∝ b x c

[0054] (T; light transmittance, b; optical path length (corresponding to the thickness of the resin film), c: concentration of solute (corresponding to the concentration of solid components of the photosensitive resin composition)).

[0055] The photosensitive resin composition of the present application is preferably one in which the film stress calculated from the change in the deflection amount of the silicon wafer substrate before and after the formation of a resin film having a thickness of 9 μm on the silicon wafer substrate is 5 MPa or more and 30 MPa or less, the resin film having a thickness of 9 μm being formed by applying the photosensitive resin composition to a 4-inch silicon wafer substrate to form a coating film, and then performing exposure by irradiation of ultraviolet rays under conditions of an exposure dose of 70 mJ / cm 2 and then heating using an oven at 230°C for 30 minutes.

[0056] In addition, the film stress is a stress defined in the central plane of the wall thickness in a shell structure in which the wall thickness is sufficiently smaller than the radius of curvature of the central plane (curved surface), and is defined by the following Stoney's equation.

[0057] Film stress σ (Pa) = E / (1 - v) x h 2 / 6t x (1 / R1 - 1 / R0)

[0058] Here, E / (1 - v) is the biaxial elastic coefficient of the substrate, and is 1.805 x 10 -11 Pa in the case of a silicon wafer substrate. h is the thickness (m) of the substrate, t is the thickness (m) of the resin film, R1 is the radius of curvature (m) of the substrate after the formation of the resin film, and R0 is the radius of curvature (m) of the substrate before the formation of the resin film.

[0059] As a method for measuring R0 and R1, there is a method in which R0 is measured before the formation of the resin film and R1 is measured after the formation of the resin film. In addition, in the case where R0 cannot be measured in advance, it is possible to measure R1 using the substrate on which the resin film is formed, and to measure R0 using a substrate of the same specifications as the substrate on which the resin film is formed (using another substrate on which no resin film is formed as a reference).

[0060] Since the film stress is 5 MPa or more and 30 MPa or less, in the above formula, it is preferable that h 2 × (1 / R1-1 / R0) is 150 to 900 x 10 11 (m) Such a calculation.

[0061] In addition, as the substrate, even when a resin film is provided using the photosensitive resin composition of the present application on another substrate, for example, a glass substrate of 1.5 x 1.5 m, the warpage of the glass substrate can be similarly mitigated, and the processability (i.e., conveyability) is excellent.

[0062] The photosensitive resin composition of the present application can further contain (4) an ultraviolet absorber. The content of the ultraviolet absorber is preferably 0.05 mass% or more and 8 mass% or less in the solid content. By causing the photosensitive resin composition to contain the ultraviolet absorber, the ultraviolet rays as the exposure light not only reach the surface but also efficiently reach as far as the deep portion. If the exposure light reaches as far as the deep portion of the film, the resolution in the exposure and development processes is improved. If the resolution of the obtained overcoat film is improved, it is possible to process into a finer pattern, and it is possible to be applied to a high-performance fingerprint sensor.

[0063] On the other hand, by causing the content of the ultraviolet absorber to be 8 mass% or less, even in the case where a thick film resin film is formed using the photosensitive resin composition, coloring is substantially not exhibited. Thereby, it becomes easy to make the transmittance of light of a wavelength of 380 to 780 nm when the thickness of the resin film is 9 μm be 90 to 100%.

[0064] As (4) the ultraviolet absorber which maintains transparency while the photosensitivity is excellent, a benzotriazole-based compound, a benzophenone-based compound, a triazine-based compound can be given. Two or more of them can be contained. Specifically, 2-hydroxy-4-n-octyloxybenzophenone (Octabenzone), 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimidomethyl)-5-methylphenyl]benzotriazole, 2,4-bis(1-methyl-1-phenylethyl)-6-(2H-benzotriazol-2-yl)phenol, 2-(2'-hydroxy-5'-methylacryloyloxyethylphenyl)-2H-benzotriazole, 2-hydroxy-4-n-octyloxybenzophenone, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol, and the like can be given.

[0065] The photosensitive resin composition can further contain a surfactant. By containing a surfactant, the coatability of the photosensitive resin composition and the surface smoothness of the obtained resin film can be improved. As the surfactant, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, fluorine-based surfactants, silicone-based surfactants, and the like can be given. Two or more of them can be contained. From the viewpoint of improving the coatability of the photosensitive resin composition, the content of the surfactant in the photosensitive resin composition is preferably 0.01% by mass or more in the solid content, and from the viewpoint of improving the surface smoothness of the overcoat film, it is preferably 1% by mass or less in the solid content.

[0066] The photosensitive resin composition can further contain an organic solvent, an adhesion improver, a polymerization inhibitor, and the like. As the organic solvent, acetate-based solvents, (poly)alkylene glycol ether-based solvents, aliphatic ester-based solvents, aliphatic alcohol-based solvents, ketone-based solvents, hydrocarbon-based solvents, and the like can be given. Two or more of them can be contained. From the viewpoint of improving the coatability, the content of the organic solvent in the photosensitive resin composition is preferably 40% by mass or more, and from the viewpoint of improving the drying characteristics, it is preferably 95% by mass or less. As the adhesion improver, silane coupling agents can be given. Among them, 3-methacryloyloxypropyltrimethoxysilane and 3-acryloyloxypropyltrimethoxysilane are preferable. Two or more of them can be contained. From the viewpoint of suppressing impurities, the content of the adhesion improver in the photosensitive resin composition is preferably 10% by mass or less in the solid content, and more preferably 5% by mass or less. As the polymerization inhibitor, for example, hydroquinones, catechols, and the like can be given. Two or more of them can be contained. From the viewpoint of improving the stability, the content of the polymerization inhibitor in the photosensitive resin composition is preferably 0.001% by mass or more in the solid content, and from the viewpoint of suppressing the reduction in sensitivity, it is preferably 1% by mass or less in the solid content.

[0067] In addition, the photosensitive resin composition preferably does not contain metals such as chromium and iron. If the obtained cured film contains a large amount of metal, display defects occur in display devices. The content of the metal in the photosensitive resin composition is preferably 0.001% by weight or less in the solid content, and more preferably 0.0001% by mass or less. The content of the metal in the photosensitive resin composition can be measured by, for example, an ICP emission spectroscopic analyzer.

[0068] The method for producing the photosensitive resin composition of the present application is not particularly limited, and it is preferable to produce by a general method. For example, it is preferable to obtain by stirring to dissolve after adding the above-mentioned photopolymerization initiator and the above-mentioned solvent, and adding other above-mentioned additives as necessary, in a container such as a flask, adding the above-mentioned alkali-soluble resin and the above-mentioned polymerizable compound, and further stirring for 20 minutes to 3 hours, while adding other above-mentioned additives as necessary. The obtained photosensitive resin composition can be filtered.

[0069] Next, the method for producing the resin film of the present application will be described. The above-mentioned photosensitive resin composition is applied to a substrate to form a coating film. The film in this state is also referred to as a coated film. Next, the coated film is dried. This drying step is also referred to as pre-baking, and the coated film after drying is referred to as a pre-baked film. A pattern is formed by performing development after exposing the pre-baked film. It is preferable to perform exposure of the pre-baked film through a mask to cure the exposed portion in the exposure step, and to perform development using an alkali developer to remove the unexposed portion in the development step, to perform pattern formation of the negative type. The obtained photocured pattern is further heat-cured. The film after heat-curing is referred to as a resin-cured film. In addition, in the present specification, these films are sometimes collectively referred to as resin films. In addition, the resin film formed on the substrate is sometimes particularly referred to as an overcoat film.

[0070] As the method for applying the photosensitive resin composition, methods such as micro gravure coating, spin coating, dip coating, curtain coating, roll coating, spray coating, slit coating, inkjet coating, and the like can be given.

[0071] As the substrate, transparent substrates such as a glass plate, a polymer film, and the like can be given. The substrate can have a color layer formed of a black matrix, a colored resin, or the like.

[0072] As the drying method, methods such as reduced pressure drying, heating drying using an oven, an electric hot plate, and the like can be given. In the case of reduced pressure drying, the heating temperature is preferably 100°C or lower from the viewpoint of suppressing recondensation of the solvent to the inner wall of the reduced pressure chamber. The reduced pressure drying pressure is preferably the vapor pressure of the solvent contained in the resin film or lower, and is preferably 1 to 1000 Pa. The reduced pressure drying time is preferably 10 to 600 seconds. In the case of heating drying, the heating temperature is preferably 50 to 120°C, and the heating time is preferably 1 to 60 minutes.

[0073] The resin coating film formed is developed after exposure, and thus can be formed into a fine pattern for a fingerprint sensor. For example, by exposing the resin film through a photomask in the exposure step to cure the exposed portion, and developing it using an alkaline developer in the development step to remove the unexposed portion, a fine pattern can be formed. The resulting fine pattern can be heat-cured by heating. The aperture of the fine pattern for a fingerprint sensor is preferably 40 μm or less, and more preferably 30 μm or less. If the aperture is 40 μm or less, it is also possible to form a pattern for a notch portion or a frame portion of a display.

[0074] As the exposure machine used in the exposure step, for example, a stepper exposure machine, a mirror projection aligner (MPA), a parallel light aligner (PLA), a lens scanner, and the like can be given. As the exposure light source, ultraviolet rays such as i-rays, h-rays, g-rays, KrF (wavelength 248 nm) laser light, ArF (wavelength 193 nm) laser light, and the like can be given. The exposure dose is preferably 10 to 500 mJ / cm 2 left and right (wavelength 365 nm exposure dose conversion). Exposure can be performed with or without a desired mask.

[0075] As the developing method in the development step, for example, a spraying method, an immersion method, a slurry method, and the like can be given. A method in which the exposed film is immersed in a developer for 5 seconds to 10 minutes is preferred. As the developer, an aqueous solution of an alkaline developer such as an inorganic alkali including a hydroxide, a carbonate, a phosphate, a silicate, a borate, and the like of an alkali metal such as sodium hydroxide, potassium hydroxide, an amine such as 2-diethylaminoethanol, monoethanolamine, diethanolamine, a quaternary ammonium salt such as tetramethylammonium hydroxide, choline, and the like can be given. After development, rinsing with water is preferred.

[0076] As the heating device for heat curing, for example, an electric hot plate, an oven, and the like can be given. The heat curing temperature is preferably 80 to 280°C. By making the heat curing temperature 80°C or higher, the barrier property of the resin film can be improved. On the other hand, by making the heat curing temperature 280°C or lower, thermal discoloration of the resin film can be suppressed, and high transmittance can be maintained. The heating time is preferably 5 to 60 minutes. By making the heat curing time 5 minutes or more, the barrier property of the resin film can be improved. On the other hand, by making the heat curing time 60 minutes or less, thermal discoloration of the resin film can be suppressed, and high transmittance can be maintained.

[0077] The resin film of the present application can be suitably used for a protective film for a touch panel, various hard coat materials, a planarization film for a TFT, an outer coating layer for a color filter, various protective films such as an anti-reflection film, an insulating film for a touch sensor, an insulating film for a TFT, and the like. In particular, it can be suitably used as an outer coating film for an image display device provided with a fingerprint sensor. This is because the outer coating film requires a thicker film thickness in design, and the resin cured film of the present application has low film stress even if the film thickness is thick, high visible light transparency, and can be processed into a fine pattern.

[0078] In addition, the display device provided with a fingerprint sensor is a display device in which a fingerprint sensor is provided on an image display surface of an image display device, and has a function of detecting a fingerprint by placing a finger on an image display portion. As the fingerprint sensor, a publicly known fingerprint sensor can be used. By providing a plurality of authentication sensors on the image display device, the position of the fingerprint to be detected is not limited to a specific position, and detection of the fingerprint at a plurality of positions of the image display portion can be performed.

[0079] The outer coating film for a fingerprint sensor of the present application is an outer coating film for a fingerprint sensor having a film thickness of 4 μm or more and 15 μm or less, and the transmittance of light having a wavelength of 380 to 780 nm per 9 μm thickness of the outer coating film is 90 to 100% in the entire range of the wavelength of 380 to 780 nm. If the film thickness is less than 4 μm, light reflection of visible light and infrared light for recognizing a fingerprint is increased, and the efficiency of the fingerprint sensor is decreased when the outer coating film is applied to a fingerprint sensor. If the film thickness exceeds 15 μm, the transmittance of visible light is decreased, and the display function is decreased when the outer coating film is applied to a fingerprint sensor. In addition, if the thickness of the outer coating film is thinner or thicker than 9 μm, the transmittance per 9 μm thickness is converted by the above conversion formula.

[0080] Next, as an example of an image display device, a liquid crystal display device is described. The liquid crystal display device generally has a color filter substrate. The color filter substrate has a black matrix, colored pixels, and an outer coating film on a base material. The resin film of the present application can be suitably used as the outer coating film. As the colored pixels, pixels of red, green, blue, and the like can be given. As the pattern shape of the colored pixels, for example, a stripe shape, an island shape, and the like can be given. As the base material, for example, a glass plate, a high molecular film, and the like can be given.

[0081] As a method for manufacturing a liquid crystal display device, a method in which a color filter substrate and a driving element side substrate are opposed to each other, are attached via a spacer, liquid crystal is injected from an injection port provided in a sealing portion, the injection port is sealed, and finally an IC drive and the like are mounted can be given. By providing a thin film transistor (TFT) element or a thin film diode (TFD) element on the driving element side substrate in addition to a scan line and a signal line, a TFT liquid crystal display device or a TFD liquid crystal display device can also be manufactured.

[0082] Examples

[0083] Hereinafter, the examples of the present application will be specifically described, but the present application is not limited to these. The evaluation methods and the production methods used in each of the examples and comparative examples are shown below.

[0084] (Synthesis of alkali-soluble resin 1)

[0085] After 84 g of methacrylic acid, 1.8 g of benzyl methacrylate, 2.2 g of tricyclodecane methacrylate, 3 g of 2,2'-azobis(2-methylbutyronitrile), and 220 g of PGMEA were added to a polymerization vessel, the liquid temperature was raised to 100°C after stirring for 2 hours at 90°C under a nitrogen atmosphere, and the reaction was further allowed to proceed for 5 hours. Next, the polymerization vessel was subjected to air replacement, 97 g of glycidyl methacrylate, 1.2 g of dimethylbenzylamine, and 0.2 g of p-methoxyphenol were added to the resulting reaction solution, and stirring was performed for 6 hours at 110°C, 50 g of PGMEA was added at the end of the reaction, and a solution of alkali-soluble resin 1 (double bond equivalent 3200, solid content 35 mass%, Mw 12000) was obtained.

[0086] (Synthesis of alkali-soluble resin 2)

[0087] After 33 g of methyl methacrylate, 33 g of styrene, 34 g of methacrylic acid, 3 g of 2,2'-azobis(2-methylbutyronitrile), and 140 g of PGMEA were added to a polymerization vessel, the liquid temperature was raised to 100°C after stirring for 2 hours at 90°C under a nitrogen atmosphere, and the reaction was further allowed to proceed for 1 hour. Next, air replacement was performed, 20 g of glycidyl methacrylate, 1.2 g of dimethylbenzylamine, and 0.2 g of p-methoxyphenol were added to the resulting reaction solution, and stirring was performed for 4 hours at 90°C, 30 g of PGMEA was added at the end of the reaction, and a solution of alkali-soluble resin 2 (double bond equivalent 600, solid content 40 mass%, Mw 23000) was obtained.

[0088] (Synthesis of alkali-soluble resin 3)

[0089] After 33 g of methyl methacrylate, 33 g of styrene, 0.3 g of tricyclodecane methacrylate, 34 g of methacrylic acid, 3 g of 2,2'-azobis(2-methylbutyronitrile), and 140 g of PGMEA were added to a polymerization vessel, the liquid temperature was raised to 100°C after stirring for 2 hours at 90°C, and the reaction was further allowed to proceed for 1 hour. To the resulting reaction solution, 20 g of glycidyl methacrylate, 1.2 g of dimethylbenzylamine, and 0.2 g of p-methoxyphenol were added, and stirring was performed at 90°C for 4 hours, and 50 g of PGMEA was added at the end of the reaction to obtain a solution of alkali-soluble resin 3 (double bond equivalent 2500, solid content 35 mass%, Mw 8,000).

[0090] (Synthesis of alkali-soluble resin 4)

[0091] After 33 g of methyl methacrylate, 33 g of styrene, 0.2 g of tricyclodecane methacrylate, 34 g of methacrylic acid, 3 g of 2,2'-azobis(2-methylbutyronitrile), and 140 g of PGMEA were added to a polymerization vessel, the liquid temperature was raised to 100°C after stirring for 2 hours at 90°C, and the reaction was further allowed to proceed for 1 hour. To the resulting reaction solution, 20 g of glycidyl methacrylate, 1.2 g of dimethylbenzylamine, and 0.2 g of p-methoxyphenol were added, and stirring was performed at 90°C for 4 hours, and 100 g of PGMEA was added at the end of the reaction to obtain a solution of alkali-soluble resin 4 (double bond equivalent 1900, solid content 25 mass%, Mw 6,000).

[0092] (Example 1)

[0093] An alkali-soluble resin 1 synthesized as above, 6.18 g, a polymerizable compound ("pentaerythritol triacrylate" manufactured by Kolon Chemical Co., Ltd., 6.97 g, a photopolymerization initiator ("ADEKA ARKLUZ" (registered trademark) NCI-930 manufactured by ADEKA, 0.39 g, an ultraviolet absorber (Tinuvin 234 manufactured by BASF, 0.39 g, a polymerization inhibitor (tert-butylcatechol (hereinafter, TBC) manufactured by DIC Corporation, 0.01 g, a surfactant ("BYK" (registered trademark) -333 manufactured by BYK, 0.040 g, and propylene glycol monomethyl ether as a solvent, 86.02 g were mixed to produce a photosensitive resin composition.

[0094] (Examples 2 to 8, Comparative Examples 1 to 6, Reference Examples 1 to 2)

[0095] The kind and the mixing amount of each component were changed as described in Tables 1 and 2, and otherwise, the same operation as in Example 1 was performed to produce a photosensitive resin composition. In addition, the content of each component in the table was all in parts by mass.

[0096] (Determination of the content of metal)

[0097] After the photosensitive resin composition produced in each of the examples and comparative examples was subjected to heat decomposition using nitric acid, sulfuric acid, and perchloric acid, and then subjected to warm dissolution using dilute nitric acid, it was made constant in volume. With respect to this solution, the metal content of chromium, iron, and the like was determined using an ICP emission spectrometry device (PS3520VDDII by Hitachi High-Tech Science, Inc.), and the mass % with respect to the solid content in the photosensitive resin composition was calculated. The results are shown in Tables 1 and 2.

[0098] (Determination of film stress)

[0099] The photosensitive resin composition produced in each of the examples and comparative examples was coated on a 4-inch silicon wafer substrate having a thickness of 0.5 mm to form a coating film, and was pre-baked using a hot plate at 90°C for 2 minutes. After exposure to ultraviolet rays under conditions of an exposure amount of 70 mJ / cm 2 , the coating film after pre-baking was subjected to exposure, and then subjected to development using 0.0428% aqueous potassium hydroxide solution for 40 seconds. Then, the resin film was formed to have a thickness of 9.0 μm by heating using an oven at 230°C for 30 minutes. The change in the deflection amount of the silicon wafer substrate before and after the formation of the resin film was determined using a thin film stress measuring device (FLX-2320-S by Toyo Technica Corporation), and the film stress value was calculated. The results are shown in Tables 1 and 2.

[0100] (Determination of transmittance)

[0101] The photosensitive resin composition produced in each of the examples and comparative examples was coated on a glass substrate to form a coating film, and was pre-baked using a hot plate at 90°C for 2 minutes. After exposure to ultraviolet rays under conditions of an exposure amount of 70 mJ / cm 2 , the coating film after pre-baking was subjected to exposure, and then subjected to development using 0.0428% aqueous potassium hydroxide solution for 40 seconds. The resin film was formed to have a thickness of 9.0 μm by heating using an oven at 230°C for 30 minutes. The transmittance of light having a wavelength of 380 to 780 nm was determined using a high-precision CF substrate optical inspection device (LCF-100MA_SF by Otsuka Electronics Co., Ltd.) for the resin film. The results are shown in Tables 1 and 2.

[0102] (Determination of volume shrinkage rate)

[0103] The photosensitive resin composition produced in each of the examples and comparative examples was added to a reduced-pressure drier and left for 2 hours to volatilize the solvent, and then the density (p) was calculated using a specific gravity measuring kit AD-1653 manufactured by A and D Co., Ltd., using distilled water as a displacement liquid. Next, the photosensitive resin composition was filled in a Teflon (registered trademark) container having a diameter of 2 cm and a height of 0.5 mm, and cured by irradiation of active energy rays (exposure amount: 70 mJ / cm 2 ) using a metal halide lamp. The cured resin cured product was subjected to the same operation as above to calculate the density (p). The volume shrinkage was calculated from each of the obtained densities, and the results are shown in Tables 1 and 2.

[0104] (Evaluation of fine pattern processability)

[0105] The photosensitive resin composition produced in each of the examples and comparative examples was coated on a glass substrate to form a coated film, and pre-baked using an electric hot plate at 90°C for 2 minutes. After the pre-baking, the coated film was subjected to mask exposure by irradiation of ultraviolet rays under the conditions of an exposure amount of 70 mJ / cm 2 using a photomask having patterns with hole diameters of 30 μm and 40 μm, and then developed using a 0.0428% aqueous potassium hydroxide solution for 40 seconds. Then, the resin film was heated using an oven at 230°C for 30 minutes to obtain a resin film having a thickness of 9.0 μm.

[0106] The fine pattern processability was evaluated by magnifying and observing the patterns with hole diameters of 30 μm and 40 μm in the resin film using an optical microscope at a magnification of 100 to 500 times, and confirming the presence or absence of a residual film. Figure 1 Fig. 1 shows an example of a schematic cross-sectional view in the case where a fine pattern 2 with a hole diameter of 40 μm was formed in a resin film 1 having a thickness of 9.0 μm. Figure 1 (a) shows the case where the pattern can be formed without a residual film, Figure 1 (b) shows the case where there is a residual film. In the case where the pattern with a hole diameter of 30 μm can be formed without a residual film, it is marked as "≤ 30 μm"; in the case where the pattern with a hole diameter of 30 μm has a residual film, but the pattern with a hole diameter of 40 μm can be formed without a residual film, it is marked as "≤ 40 μm"; and in the case where the patterns with hole diameters of 30 μm and 40 μm both have residual films, it is marked as "> 40 μm". The results are shown in Tables 1 and 2.

[0107] In addition, the symbols in Tables 1 and 2 are as follows.

[0108] A: Base-soluble resin 1 containing a unit derived from tricyclodecane methyl methacrylate with a double bond equivalent of 3200

[0109] B: Base-soluble resin 2 with double bond equivalent 600, not containing units derived from tricyclodecane methacrylate

[0110] G: Base-soluble resin 3 with double bond equivalent 2500, containing units derived from tricyclodecane methacrylate

[0111] H: Base-soluble resin 4 with double bond equivalent 1900, containing units derived from tricyclodecane methacrylate

[0112] C: Polymerizable compound: pentaerythritol triacrylate

[0113] D: Photobleaching photopolymerization initiator: Adeka Arone (registered trademark) NCI-930

[0114] E: Non-photobleaching photopolymerization initiator: Adeka Arone (registered trademark) NCI-831

[0115] F: Ultraviolet absorber: Tinuvin 234

[0116] J: Polymerization inhibitor: TBC

[0117] Z: Surfactant: BYK (registered trademark) -333

[0118]

[0119]

[0120] According to the results of the above-described implementation, it was found that in the schemes of Example 1 to Example 8, the film stress was 30 MPa or less, and a fine pattern of a pore diameter of 40 μm could be formed without a residual film. As a result, it was found that the resin film obtained from the resin composition of the present application was low in stress even if it was a thick film, and could be processed into a fine pattern, and thus could be applied to an outer coating film of a high-performance fingerprint sensor.

[0121] Figure 2 FIG. 1 shows an example of a schematic perspective view of a fingerprint sensor. In the fingerprint sensor, the outer coating film 1 of the present application is formed on a color filter substrate 3. A fine pattern 2 of pores is formed in the outer coating film 1.

[0122] Explanation of symbols

[0123] 1 Resin film

[0124] 2 Fine pattern of pores

[0125] 3 Color filter substrate.

Claims

1. A photosensitive resin composition comprising (1) an alkali-soluble resin, (2) a polymerizable compound, and (3) a photopolymerization initiator, wherein the (1) alkali-soluble resin has a double bond equivalent of 2500 to 4000, and a resin film having a thickness of 9 μm obtained from the photosensitive resin composition has a transmittance of 90 to 100% for light with a wavelength of 380 to 780 nm over the entire wavelength range of 380 to 780 nm.

2. The photosensitive resin composition according to claim 1, wherein the photosensitive resin composition is exposed to an amount of 70 mJ / cm 2 The volume shrinkage of the photosensitive resin composition before and after curing under the conditions of 8% or less. 3 . The photosensitive resin composition according to claim 1 , wherein the (2) polymerizable compound includes a compound having a hydroxyl group. 4 . The photosensitive resin composition according to claim 1 , wherein the (3) photopolymerization initiator comprises a photobleaching-type photopolymerization initiator. 5 . The photosensitive resin composition according to claim 1 , further comprising (4) an ultraviolet absorber, wherein the content of the (4) ultraviolet absorber is 0.05% by mass or more and 8% by mass or less in the solid content.

6. The photosensitive resin composition according to claim 1 or 2, wherein a film stress calculated from a change in the deflection of a silicon wafer substrate before and after formation of a resin film having a thickness of 9 μm is 5 MPa or more and 30 MPa or less when the resin film is formed on a silicon wafer substrate, wherein the resin film having a thickness of 9 μm is formed by coating the photosensitive resin composition on a 4-inch silicon wafer substrate and the exposure dose is 70 mJ / cm 2 The film was exposed to ultraviolet light under the conditions of , and then heated in an oven at 230° C. for 30 minutes.

7. The photosensitive resin composition according to claim 6, wherein when the resin film is formed on the substrate, h 2 ×(1 / R1-1 / R0) becomes 150~900×10 11 The range, its unit is m; Here, h represents the thickness of the substrate, R1 represents the curvature radius of the substrate when a resin film is formed, and R0 represents the curvature radius of the substrate when no film is formed. The units of h, R1, and R0 are all m. 8 . The photosensitive resin composition according to claim 1 , which is used for a display device equipped with a fingerprint sensor.

9. An overcoat film for a fingerprint sensor, the overcoat film being formed from the photosensitive resin composition according to any one of claims 1 to 8, the overcoat film having a film thickness of not less than 4 μm and not more than 15 μm, and a transmittance of the overcoat film for light having a wavelength of 380 to 780 nm per 9 μm of thickness being 90 to 100% over the entire wavelength range of 380 to 780 nm.

10. The fingerprint sensor overcoat film according to claim 9, wherein a film stress calculated from a change in deflection of a substrate before and after formation of a 9 μm thick resin film is 5 MPa to 30 MPa.

11. The outer coating film for a fingerprint sensor according to claim 9 or 10, when formed on a substrate, 2 ×(1 / R1-1 / R0) becomes 150~900×10 11 The range, its unit is m; Here, h represents the thickness of the substrate, R1 represents the curvature radius of the substrate when a resin film is formed, and R0 represents the curvature radius of the substrate when no film is formed. The units of h, R1, and R0 are all m. 12 . A fingerprint sensor comprising the outer coating film according to claim 9 .

13. A display device comprising the fingerprint sensor according to claim 12.

Images