JP7510752B2 - Substrate for display device, manufacturing method thereof, and resin composition solution for anti-reflection layer used therein - Google Patents

Description

The present invention relates to a substrate for a display device and a manufacturing method thereof, and a resin composition solution for an anti-reflection layer used therein, and more specifically, to a substrate for a display device having a light-shielding film and a manufacturing method thereof, and a resin composition solution for an anti-reflection layer used therein.

In display devices such as liquid crystal displays, light-shielding films such as black matrices in a grid, stripe or mosaic pattern are formed at the boundaries of each pixel of red, green, blue, etc., in order to improve contrast and prevent light leakage. Known light-shielding films of this type are formed on a transparent substrate using a photosensitive resin composition containing a light-shielding component such as a black pigment. However, in display devices that include a transparent substrate on whose surface such a light-shielding film is disposed, there is a problem in that light incident from the transparent substrate side is reflected by the surface of the light-shielding film (the interface with the transparent substrate), causing surrounding objects to be reflected on the screen.

Therefore, in order to solve such problems as reflection, a method of suppressing the reflection of light on the surface of the light-shielding film has been studied. For example, International Publication No. 2010/070929 (Patent Document 1) describes that in a display panel substrate having a transparent substrate and a light-shielding layer, two types of light-shielding layers with different optical densities are provided as light-shielding layers on the transparent substrate, and a light-shielding layer with a lower optical density than the light-shielding layer with a higher optical density is disposed between the transparent substrate and the light-shielding layer with a higher optical density, thereby suppressing the reflection of light on the surface of the light-shielding layer. In addition, International Publication No. 2014/178149 (Patent Document 2) describes that in a display substrate having a transparent substrate and a black matrix, a reflectance-reducing layer and a light-shielding layer having an effective optical density within a specific range as a black matrix are laminated on the transparent substrate, thereby suppressing the reflection of light on the surface of the black matrix.

International Publication No. 2010/070929 International Publication No. 2014/178149

However, in the display device substrates described in Patent Documents 1 and 2, the reflection of light on the surface of the light-shielding film (light-shielding layer, black matrix) is not necessarily sufficiently suppressed, and in order to improve contrast and prevent light leakage, it is necessary to further suppress the reflection of light on the light-shielding film.

The present invention was made in consideration of the problems with the above-mentioned conventional technology, and aims to provide a display device substrate having a light-shielding film that sufficiently suppresses light reflection, and a manufacturing method thereof.

As a result of intensive research by the inventors to achieve the above object, they discovered that in a display device substrate having a transparent substrate and a light-shielding film, by providing a light-shielding film on a transparent substrate, which comprises an anti-reflection layer and a light-shielding layer as a light-shielding film, and in which the surface roughness of the anti-reflection layer at the interface between the anti-reflection layer and the light-shielding layer is within a specific range, reflection of light on the light-shielding film surface can be further suppressed, leading to the completion of the present invention.

That is, the display device substrate of the present invention is characterized in that it comprises a transparent substrate, an antireflection layer disposed on the transparent substrate, the antireflection layer containing an inorganic filler with a refractive index of 1.2 to 1.8 and a transparent resin cured product and having an average thickness of 0.01 to 1 μm, and a light-shielding layer disposed on the antireflection layer, the antireflection layer containing at least one light-shielding component selected from the group consisting of organic black pigments, inorganic black pigments, and mixed-color pseudo-black pigments and a resin cured product and having an average thickness of 0.1 to 30 μm, and the antireflection layer has a surface roughness of 40 to 200 nm at the interface between the antireflection layer and the light-shielding layer.

In such a display device substrate, the inorganic filler preferably has an average particle size of 25 to 300 nm, and the content of the inorganic filler is preferably 5 to 95% by mass relative to the entire anti-reflection layer.

A first method for producing a substrate for a display device according to the present invention is a method for producing a substrate for a display device including a transparent substrate and a light-shielding film formed on the transparent substrate and including an antireflection layer and a light-shielding layer, the method comprising the steps of:
forming a resin composition layer for an antireflection layer on the transparent substrate, the resin composition layer containing an inorganic filler having a refractive index of 1.2 to 1.8 and a photocurable transparent resin, the resin composition layer having an average thickness of 0.01 to 1 μm and a surface roughness of 40 to 200 nm;
forming a resin composition layer for a light-shielding layer, the resin composition layer containing at least one light-shielding component selected from the group consisting of an organic black pigment, an inorganic black pigment, and a mixed color pseudo-black pigment, and a photocurable resin, on the resin composition layer for an antireflection layer;
a step of simultaneously subjecting the resin composition layer for an antireflection layer and the resin composition layer for a light-shielding layer to an exposure treatment, simultaneously subjecting the resin composition layer for an antireflection layer and the resin composition layer for a light-shielding layer to a development treatment, and further subjecting the resin composition layer to a heat treatment (post-baking) to form an antireflection layer containing the inorganic filler and a transparent cured resin and a light-shielding layer containing the light-shielding component and a cured resin and having an average thickness of 0.1 to 30 μm;
The method is characterized by comprising:

In such a first method for manufacturing a substrate for a display device, it is preferable that both the photocurable transparent resin in the resin composition layer for the antireflection layer and the photocurable resin in the resin composition layer for the light-shielding layer are alkali-soluble, and the development treatment is an alkali development treatment.

Further, a second manufacturing method of a substrate for a display device of the present invention is a manufacturing method of a substrate for a display device including a transparent substrate and a light-shielding film formed of an antireflection layer and a light-shielding layer and disposed on the transparent substrate, the method comprising the steps of:
a step of subjecting a resin composition for an antireflection layer, which contains an inorganic filler having a refractive index of 1.2 to 1.8 and at least one of a thermosetting transparent resin and a thermosetting monomer, to a heat curing treatment to form an antireflection layer having an average thickness of 0.01 to 1 μm and a surface roughness of 40 to 200 nm on the transparent substrate;
a step of subjecting a resin composition for a light-shielding layer, which contains at least one light-shielding component selected from the group consisting of an organic black pigment, an inorganic black pigment, and a mixed color pseudo-black pigment, and a photocurable resin, to an exposure treatment, followed by a development treatment, and further a heat treatment (post-baking) to form a light-shielding layer having an average thickness of 0.1 to 30 μm on the antireflection layer;
The method is characterized by comprising:

In such a second method for producing a substrate for a display device, it is preferable that the photocurable resin in the resin composition for a light-shielding layer is alkali-soluble, and the development treatment is an alkali development treatment.

The first resin composition solution for an antireflection layer of the present invention contains a photocurable resin composition and an organic solvent,
the photocurable resin composition contains 5 to 95 mass % of an inorganic filler having a refractive index of 1.2 to 1.8 and an average particle size of 25 to 300 nm, based on the entire resin composition; 1.54 to 95 mass % of a photocurable transparent resin, based on the entire resin composition; 0 to 50 mass % of a photopolymerizable monomer, based on the total amount of the photocurable transparent resin and the photopolymerizable monomer; and 0 to 30 mass parts of a photopolymerization initiator, based on 100 mass parts of the total amount of the photocurable transparent resin and the photopolymerizable monomer;
the content of the organic solvent is 80 to 99.9% by mass based on the total amount of the photocurable resin composition and the organic solvent;
The solution has a viscosity of 1 to 4 mPa·sec.

Further , the second resin composition solution for an antireflection layer of the present invention contains a thermosetting resin composition and an organic solvent,
the thermosetting resin composition contains 5 to 95 mass % of an inorganic filler having a refractive index of 1.2 to 1.8 and an average particle size of 25 to 300 nm, based on the entire resin composition; 3.2 to 94.06 mass % of at least one of a thermosetting transparent resin and a thermosetting monomer, based on the entire resin composition; and 1 to 25 mass parts of a heat curing agent, based on 100 mass parts of the total amount of the thermosetting transparent resin and the thermosetting monomer;
the content of the organic solvent is 80 to 99.9% by mass based on the total amount of the thermosetting resin composition and the organic solvent;
The solution has a viscosity of 1 to 4 mPa·sec.

According to the present invention, it is possible to obtain a display device substrate having a light-shielding film in which light reflection is sufficiently suppressed.

The present invention will be described in detail below with reference to preferred embodiments.

First, the display substrate of the present invention will be described. The display substrate of the present invention comprises a transparent substrate, an anti-reflection layer disposed on the transparent substrate, the anti-reflection layer containing an inorganic filler having a refractive index within a specific range and a transparent resin cured product, and an average thickness within a specific range, and a light-shielding layer disposed on the anti-reflection layer, the anti-reflection layer containing at least one light-shielding component selected from the group consisting of an organic black pigment, a mixed-color pseudo-black pigment, and an inorganic black pigment, and a resin cured product, the average thickness within a specific range, and a light-shielding layer having a surface roughness within a specific range at the interface between the anti-reflection layer and the light-shielding layer.

There are no particular limitations on the transparent substrate used in the present invention, and examples include glass substrates, transparent resin films (PET films, PEN films, polycarbonate films, polyimide films, etc.), and transparent substrates used in known display devices.

The light-shielding film of the present invention is composed of an anti-reflection layer and a light-shielding layer, and in the display device substrate of the present invention, it constitutes a color filter, a black matrix of a CMOS sensor, a frame (bezel) for a touch panel, a black column spacer, a black partition (bank material), etc. In addition, such a light-shielding film is disposed on the transparent substrate, and more specifically, an anti-reflection layer is disposed on the transparent substrate, and a light-shielding layer is disposed on the anti-reflection layer.

The anti-reflection layer contains an inorganic filler with a refractive index of 1.2 to 1.8. An inorganic filler with such a refractive index has a refractive index smaller than that of the light-shielding component described below. By using an inorganic filler with such a small refractive index, the reflectance of the light-shielding film is reduced, and the reflection of light at the light-shielding film is suppressed. The refractive index of such an inorganic filler is preferably 1.3 to 1.6, and more preferably 1.4 to 1.5.

Inorganic fillers having such a refractive index include silica (refractive index: 1.46), magnesium fluoride (refractive index: 1.38), lithium fluoride (refractive index: 1.39), calcium fluoride (refractive index: 1.40), etc., and among these, silica (refractive index: 1.46) is particularly preferred. In addition, such inorganic fillers (particularly silica) are preferably manufactured or surface-treated so as to be dispersible in an organic solvent. Examples of silica manufactured or surface-treated so as to be dispersible in such an organic solvent include fumed silica, colloidal silica, and organosilica sol. For example, products sold under the trade names of organosilica sol manufactured by Nissan Chemical Co., Ltd., Adma Fine and Admanano manufactured by Admatechs Co., Ltd., colloidal silica, organosilica sol, and silica nanopowder manufactured by Fuso Chemical Co., Ltd., and fumed silica manufactured by Nippon Aerosil Co., Ltd., which are dispersible in organic solvents, can be used.

The average particle size of the inorganic filler is preferably 25 to 300 nm, more preferably 30 to 260 nm, and particularly preferably 30 to 220 nm. If the average particle size of the inorganic filler is less than the lower limit, the surface roughness of the antireflection layer at the interface between the antireflection layer and the light-shielding layer tends to be less than the lower limit of the specified range, while if it exceeds the upper limit, the surface roughness of the antireflection layer at the interface between the antireflection layer and the light-shielding layer tends to exceed the upper limit of the specified range. The average particle size of the inorganic filler can be determined by particle size distribution measurement using a dynamic light scattering method or the like.

The content of the inorganic filler is preferably 5 to 95% by mass, more preferably 15 to 90% by mass, and particularly preferably 25 to 85% by mass, based on the total amount of the anti-reflection layer. If the content of the inorganic filler is less than the lower limit, the surface roughness of the anti-reflection layer at the interface between the anti-reflection layer and the light-shielding layer tends to be less than the lower limit of the specified range, whereas if the content of the inorganic filler is greater than the upper limit, the surface roughness of the anti-reflection layer at the interface between the anti-reflection layer and the light-shielding layer tends to exceed the upper limit of the specified range.

The anti-reflection layer contains a transparent resin cured product. There are no particular limitations on the transparent resin cured product, and examples thereof include photocurable transparent resins, thermosetting transparent resins, and cured products of thermosetting monomers, which will be described later. The content of the transparent resin cured product is preferably 4 to 95% by mass, more preferably 9 to 85% by mass, and particularly preferably 14 to 75% by mass, based on the total amount of the anti-reflection layer. If the content of the transparent resin cured product is less than the lower limit, the surface roughness of the anti-reflection layer at the interface between the anti-reflection layer and the light-shielding layer tends to exceed the upper limit of a predetermined range, and on the other hand, if the content exceeds the upper limit, the surface roughness of the anti-reflection layer at the interface between the anti-reflection layer and the light-shielding layer tends to be less than the lower limit of a predetermined range.

In the light-shielding film according to the present invention, the average thickness of the anti-reflection layer is 0.01 to 1 μm. If the average thickness of the anti-reflection layer is less than the lower limit, the surface roughness of the anti-reflection layer at the interface between the anti-reflection layer and the light-shielding layer tends to exceed the upper limit of the specified range, and if the average thickness exceeds the upper limit, the surface roughness of the anti-reflection layer at the interface between the anti-reflection layer and the light-shielding layer tends to be less than the lower limit of the specified range. From the viewpoint that the surface roughness of the anti-reflection layer is likely to be within the specified range, the average thickness of the anti-reflection layer is preferably 0.02 to 0.5 μm, and more preferably 0.04 to 0.3 μm. The average thickness of the anti-reflection layer can be determined by measuring the step between the anti-reflection layer surface and the transparent substrate surface using a stylus-type step shape measuring device and averaging the steps.

The light-shielding layer contains at least one light-shielding component selected from the group consisting of organic black pigments, inorganic black pigments, and mixed-color pseudo-black pigments. Examples of organic black pigments include perylene black, aniline black, cyanine black, and lactam black. Examples of inorganic black pigments include carbon black, chromium oxide, iron oxide, and titanium black. Examples of mixed-color pseudo-black pigments include those obtained by mixing two or more pigments selected from red, blue, green, purple, yellow, cyanine, magenta, and the like to produce a pseudo-black color. These light-shielding components may be used alone or in combination of two or more. Among these light-shielding components, carbon black is particularly preferred from the viewpoints of good light-shielding properties, surface smoothness, dispersion stability, and compatibility with resins.

The average particle size of the light-shielding component is preferably 10 to 300 nm, more preferably 30 to 250 nm, and particularly preferably 50 to 220 nm. If the average particle size of the light-shielding component is less than the lower limit, the light-shielding properties of the light-shielding layer tend to decrease, while if it exceeds the upper limit, the surface smoothness of the light-shielding layer and the uniformity of dispersion of the light-shielding component tend to decrease. The average particle size of the light-shielding component can be determined by particle size distribution measurement using a dynamic light scattering method or the like.

When carbon black is used as the light-shielding component, the content of the light-shielding component is preferably 10 to 65% by mass, more preferably 15 to 60% by mass, and particularly preferably 20 to 55% by mass, based on the entire light-shielding layer. When a light-shielding component other than carbon black is used as the light-shielding component, the content is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and particularly preferably 30 to 70% by mass, based on the entire light-shielding layer. If the content of the light-shielding component is less than the lower limit, the light-shielding properties of the light-shielding layer tend to decrease, while if the content exceeds the upper limit, the surface smoothness of the light-shielding layer and the uniformity of dispersion of the light-shielding component tend to decrease.

The light-shielding layer contains a cured resin. There are no particular limitations on the type of cured resin, and examples include cured products of photocurable resins described below. When carbon black is used as the light-shielding component, the content of the cured resin is preferably 34 to 90% by mass, more preferably 39 to 85% by mass, and particularly preferably 44 to 80% by mass, based on the entire light-shielding layer. When a light-shielding component other than carbon black is used as the light-shielding component, the content is preferably 9 to 90% by mass, more preferably 19 to 80% by mass, and particularly preferably 29 to 70% by mass, based on the entire light-shielding layer. If the content of the cured resin is less than the lower limit, the surface smoothness of the light-shielding layer and the uniformity of the dispersion of the light-shielding component tend to decrease, while if the content exceeds the upper limit, the light-shielding properties of the light-shielding layer tend to decrease.

In the light-shielding film of the present invention, the average thickness of the light-shielding layer is 0.1 to 30 μm. If the average thickness of the light-shielding layer is less than the lower limit, the light-shielding properties of the light-shielding layer are reduced, while if the average thickness exceeds the upper limit, the time required for alkaline development is increased, resulting in reduced productivity. From the viewpoint of achieving both light-shielding properties and productivity, the average thickness of the light-shielding layer is preferably 0.5 to 20 μm, and more preferably 1 to 10 μm. The average thickness of the light-shielding layer can be determined by measuring the step between the light-shielding film surface and the transparent substrate surface using a stylus-type step shape measuring device, averaging the steps to determine the average thickness of the light-shielding film, and subtracting the average thickness of the antireflection layer from the average thickness of the light-shielding film.

In addition, in the light-shielding film according to the present invention, the surface roughness of the antireflection layer at the interface between the antireflection layer and the light-shielding layer is 40 to 200 nm. If the surface roughness of the antireflection layer is less than the lower limit, the reflectance of the light-shielding film is not sufficiently reduced, and the reflection of light at the light-shielding film cannot be sufficiently prevented. On the other hand, if the surface roughness of the antireflection layer exceeds the upper limit, it becomes difficult to achieve the desired level of flatness of the light-shielding film. The surface roughness of such an antireflection layer is preferably 50 to 180 nm, more preferably 80 to 160 nm, from the viewpoints of reducing the reflectance of the light-shielding film, suppressing the reflection of light at the light-shielding film, and ensuring the flatness of the light-shielding film.

Next, a method for producing a substrate for a display device of the present invention will be described. The first method for producing a substrate for a display device of the present invention is a method for producing a substrate for a display device including a transparent substrate and a light-shielding film formed of an antireflection layer and a light-shielding layer and disposed on the transparent substrate,
forming a resin composition layer for an antireflection layer on the transparent substrate, the resin composition layer containing an inorganic filler having a refractive index within a specific range and a photocurable transparent resin, the resin composition layer having an average thickness of 0.01 to 1 μm and a surface roughness of 40 to 200 nm;
forming a resin composition layer for a light-shielding layer, the resin composition layer containing at least one light-shielding component selected from the group consisting of an organic black pigment, an inorganic black pigment, and a mixed color pseudo-black pigment, and a photocurable resin, on the resin composition layer for an antireflection layer;
a step of simultaneously subjecting the resin composition layer for an antireflection layer and the resin composition layer for a light-shielding layer to an exposure treatment, simultaneously subjecting the resin composition layer for an antireflection layer and the resin composition layer for a light-shielding layer to a development treatment, and further subjecting the resin composition layer to a heat treatment (post-baking) to form an antireflection layer containing the inorganic filler and a transparent cured resin and a light-shielding layer containing the light-shielding component and a cured resin and having an average thickness of 0.1 to 30 μm;
The method includes:

A second method for producing a substrate for a display device according to the present invention is a method for producing a substrate for a display device including a transparent substrate and a light-shielding film formed on the transparent substrate and including an antireflection layer and a light-shielding layer, the method comprising the steps of:
a step of subjecting a resin composition for an antireflection layer, the resin composition containing an inorganic filler having a refractive index within a specific range and at least one of a thermosetting transparent resin and a thermosetting monomer, to a heat curing treatment to form an antireflection layer having an average thickness of 0.01 to 1 μm and a surface roughness of 40 to 200 nm on the transparent substrate;
a step of subjecting a resin composition for a light-shielding layer, which contains at least one light-shielding component selected from the group consisting of an organic black pigment, an inorganic black pigment, and a mixed color pseudo-black pigment, and a photocurable resin, to an exposure treatment, followed by a development treatment, and further a heat treatment (post-baking) to form a light-shielding layer having an average thickness of 0.1 to 30 μm on the antireflection layer;
In such a second method for producing a substrate for a display device, after the light-shielding layer (light-shielding layer pattern) is formed, if necessary, a portion of the antireflection layer where no light-shielding layer is formed thereon (a portion where the upper light-shielding layer resin composition layer has been removed in the development treatment) may be removed by etching to form a pattern on the antireflection layer as well.

The transparent substrate, inorganic filler having a refractive index within a specific range, and light-shielding component used in the first and second manufacturing methods of the display device substrate of the present invention are the transparent substrate, inorganic filler, and light-shielding component described above in the description of the display device substrate of the present invention.

The resin composition for antireflection layer used in the first method for producing a display device substrate of the present invention (hereinafter referred to as "first resin composition for antireflection layer") contains the inorganic filler and a photocurable transparent resin. The photocurable transparent resin is not particularly limited as long as it is a transparent resin that is cured by light irradiation (for example, UV irradiation), but from the viewpoint of excellent developability, an alkali-soluble photocurable transparent resin is preferred, and from the viewpoint of excellent photocurability and patterning characteristics, an alkali-soluble resin containing a polymerizable unsaturated group described in JP 2017-72760 A, i.e., an epoxy (meth)acrylate acid adduct obtained by further reacting a reaction product of a compound having two or more epoxy groups (more preferably an epoxy compound obtained by reacting a bisphenol with an epihalohydrin) and (meth)acrylic acid (meaning "acrylic acid and/or methacrylic acid") with a polyvalent carboxylic acid or its acid anhydride, is preferred, and an epoxy acrylate acid adduct derived from a bisphenol fluorene compound is particularly preferred.

In such a resin composition for the first antireflection layer, the content of the inorganic filler is preferably 5 to 95% by mass, more preferably 15 to 90% by mass, and particularly preferably 25 to 85% by mass, based on the entire resin composition for the first antireflection layer. The content of the photocurable transparent resin is preferably 1.54 to 95% by mass, more preferably 3.46 to 85% by mass, and particularly preferably 5.38 to 75% by mass, based on the entire resin composition for the first antireflection layer. When the content of the inorganic filler is less than the lower limit (or when the content of the photocurable transparent resin exceeds the upper limit), the surface roughness of the antireflection layer at the interface between the antireflection layer and the light-shielding layer formed tends to be less than the lower limit of a predetermined range, and on the other hand, when the content of the inorganic filler exceeds the upper limit (or when the content of the photocurable transparent resin is less than the lower limit), the surface roughness of the antireflection layer at the interface between the antireflection layer and the light-shielding layer formed tends to exceed the upper limit of a predetermined range.

In addition, such a resin composition for the first antireflection layer may contain a photopolymerizable monomer. This makes it possible to optimize the sensitivity when the antireflection layer is optically processed, and to optimize the mechanical properties of the film, such as the surface hardness, of the antireflection layer formed. There are no particular limitations on such photopolymerizable monomers, and examples thereof include photopolymerizable monomers having at least one ethylenically unsaturated bond (e.g., (meth)acrylic acid esters having at least one ethylenically unsaturated bond) described in JP 2017-72760 A. The content of such photopolymerizable monomers is preferably 0 to 50% by mass, more preferably 0 to 40% by mass, and particularly preferably 0 to 30% by mass, based on the total amount of the photocurable transparent resin and the photopolymerizable monomer.

Furthermore, the resin composition for the first antireflection layer preferably contains a photopolymerization initiator. Such photopolymerization initiators are not particularly limited, and examples thereof include the photopolymerization initiators described in JP 2017-72760 A, among which oxime ester-based polymerization initiators are particularly preferred. The content of such photopolymerization initiators can be appropriately set according to the photocurability of the resin composition for the first antireflection layer, and is preferably 0 to 30 parts by mass, and more preferably 0 to 25 parts by mass, per 100 parts by mass of the total amount of the photocurable resin and the photopolymerizable monomer.

In addition, when the heat resistance of the transparent substrate is low and the heat treatment (post-baking) after development is performed at a low temperature such as 150°C or less, it is preferable that the resin composition for the first anti-reflection layer contains an azo-based polymerization initiator. This improves the thermal radical polymerizability of the resin composition for the first anti-reflection layer during heating after development (post-baking). There are no particular limitations on such azo-based polymerization initiators, and examples of such azo-based polymerization initiators include the azo-based polymerization initiators described in JP-A-2017-181976. There are no particular limitations on the content of such azo-based polymerization initiators, and the content can be appropriately set depending on the thermal radical polymerizability of the resin composition for the first anti-reflection layer, etc.

Furthermore, the resin composition for the first antireflection layer may contain various additives, such as a dispersant, a polymerization initiator other than the photopolymerization initiator and the azo-based polymerization initiator, a chain transfer agent, a sensitizer, a non-photosensitive resin, a curing agent, a curing accelerator, an antioxidant, a plasticizer, a filler, a coupling agent, a surfactant, and a dye, as necessary.

In addition, the resin composition for the first antireflection layer is preferably used in the form of a solution (i.e., as a solution of the resin composition for the first antireflection layer). This allows a uniform resin composition layer for the antireflection layer to be formed. The organic solvent used in such a resin composition solution for the first antireflection layer is not particularly limited, and examples thereof include the solvents described in JP-A-2017-72760. It is preferable to mix such an organic solvent so that the amount of the organic solvent is 80 to 99.9% by mass with respect to the total amount of the resin composition for the first antireflection layer and the organic solvent, and it is more preferable to mix such that the solution viscosity (B-type or E-type viscometer) of the resin composition solution for the first antireflection layer is 1 to 4 mPa·sec. Since the preferable range of such a solution viscosity varies depending on the coating method, the preferable range of the amount of the organic solvent also varies depending on the coating method. For example, in the case of spin coating, the amount of organic solvent is preferably 80 to 85% by mass, which is near the lower limit of the preferred range of the amount of organic solvent, and in the case of slit coating, the amount of organic solvent is preferably 99.0 to 99.9% by mass, which is near the upper limit of the preferred range of the amount of organic solvent.

The first resin composition solution for an antireflection layer according to the present invention has a typical composition, which is a resin composition solution containing a photocurable resin composition and an organic solvent,
the photocurable resin composition has a refractive index of 1.2 to 1.8, an average particle size of 30 to 220 nm, and contains 25 to 85 mass % of silica particles dispersible in the organic solvent based on the entire resin composition, and 15 to 75 mass % of an epoxy (meth)acrylate acid adduct based on the entire resin composition;
the content of the organic solvent is 80 to 99.9% by mass based on the total amount of the photocurable resin composition and the organic solvent;
The resin composition solution has a solution viscosity of 1 to 4 mPa·sec. In such a first antireflection layer resin composition solution, the epoxy (meth)acrylate acid adduct is particularly preferably an epoxy acrylate acid adduct derived from a bisphenol fluorene compound.

On the other hand, the resin composition for an anti-reflection layer used in the second method for producing a display device substrate of the present invention (hereinafter referred to as the "second resin composition for an anti-reflection layer") contains the inorganic filler and at least one of a thermosetting transparent resin and a thermosetting monomer. There are no particular limitations on the thermosetting transparent resin and the thermosetting monomer as long as they are transparent resins and monomers that are cured by heat treatment, and examples of such resins include resins having an ethylenically unsaturated double bond or a cyclic reactive group (epoxy compounds, oxetane compounds, etc.) and monomers having an ethylenically unsaturated double bond or a cyclic reactive group, as described in JP 2016-161926 A.

In such a resin composition for the second antireflection layer, the content of the inorganic filler is preferably 5 to 95% by mass, more preferably 15 to 90% by mass, and particularly preferably 25 to 85% by mass, based on the entire resin composition for the second antireflection layer. The content of at least one of the thermosetting transparent resin and the thermosetting monomer is preferably 3.2 to 94.06% by mass, more preferably 7.2 to 84.16% by mass, and particularly preferably 11.2 to 74.26% by mass, based on the entire resin composition for the second antireflection layer. When the content of the inorganic filler is less than the lower limit (or when the content of the thermosetting transparent resin exceeds the upper limit), the surface roughness of the antireflection layer at the interface between the formed antireflection layer and the light-shielding layer tends to be less than the lower limit of the specified range, and on the other hand, when the content of the inorganic filler exceeds the upper limit (or when the content of the thermosetting transparent resin is less than the lower limit), the surface roughness of the antireflection layer at the interface between the formed antireflection layer and the light-shielding layer tends to exceed the upper limit of the specified range.

In addition, it is preferable that the resin composition for the second anti-reflection layer contains a heat curing agent. Examples of such heat curing agents include amine compounds, polycarboxylic acid compounds, phenolic resins, amino resins, dicyandiamide, Lewis acid complex compounds, and other heat curing agents for epoxy compounds, and among these, polycarboxylic acid compounds are preferred. Examples of such polycarboxylic acid compounds include polycarboxylic acids, anhydrides of polycarboxylic acids, and thermally decomposable esters of polycarboxylic acids. The polycarboxylic acid is a compound having two or more carboxy groups in one molecule, and specific examples thereof include succinic acid, maleic acid, cyclohexane-1,2-dicarboxylic acid, cyclohexene-1,2-dicarboxylic acid, cyclohexene-4,5-dicarboxylic acid, norbornane-2,3-dicarboxylic acid, phthalic acid, 3,6-dihydrophthalic acid, 1,2,3,6-tetrahydrophthalic acid, methyltetrahydrophthalic acid, benzene-1,2,4-tricarboxylic acid, cyclohexane-1,2,4-tricarboxylic acid, benzene-1,2,4,5-tetracarboxylic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, etc. Examples of the anhydrides of polycarboxylic acids include the anhydrides of the polycarboxylic acids exemplified above. As the anhydrides of such polycarboxylic acids, intermolecular acid anhydrides may be used, but generally, acid anhydrides that are ring-closed within the molecule are used. Examples of the thermally decomposable ester of a polycarboxylic acid include the thermally decomposable ester of a polycarboxylic acid exemplified above (for example, t-butyl ester, 1-(alkyloxy)ethyl ester, 1-(alkylsulfanyl)ethyl ester, etc. [wherein the alkyl is a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have any structure of a straight chain, branched or cyclic structure, and may have any substituent]). In addition, a polymer or copolymer having two or more carboxy groups can be used as the polycarboxylic acid compound, and the carboxy groups may form an anhydride group or a thermally decomposable ester group. There are no particular limitations on such a polymer or copolymer having two or more carboxy groups, but examples thereof include a polymer or copolymer containing (meth)acrylic acid as a constituent, a copolymer containing maleic anhydride as a constituent, and a compound obtained by reacting a tetracarboxylic dianhydride with a diamine or diol to open the ring of the acid anhydride. Among these polycarboxylic acid compounds, the anhydrides of the polycarboxylic acids phthalic acid, 3,6-dihydrophthalic acid, 1,2,3,6-tetrahydrophthalic acid, methyltetrahydrophthalic acid, and benzene-1,2,4-tricarboxylic acid are preferred. The content of such a thermosetting agent can be appropriately set depending on the thermosetting property of the resin composition for the second antireflection layer, and is preferably, for example, 1 to 25 parts by mass per 100 parts by mass of the total amount of the thermosetting transparent resin and the thermosetting monomer.

Furthermore, the resin composition for the second antireflection layer may contain various additives, such as dispersants, non-thermosetting resins, curing accelerators, antioxidants, plasticizers, fillers, coupling agents, surfactants, and dyes, as necessary.

In addition, the second anti-reflection layer resin composition is preferably used in the form of a solution (i.e., as a second anti-reflection layer resin composition solution). This allows a uniform anti-reflection layer resin composition layer to be formed. The organic solvent used in such a second anti-reflection layer resin composition solution is not particularly limited, and examples thereof include the solvents described in JP 2016-161926 A. It is preferable to mix such an organic solvent so that the amount of the organic solvent is 80 to 99.9% by mass with respect to the total amount of the second anti-reflection layer resin composition and the organic solvent, and it is more preferable to mix such that the solution viscosity (B-type or E-type viscometer) of the second anti-reflection layer resin composition solution is 1 to 4 mPa·sec. Since the preferable range of such a solution viscosity varies depending on the coating method, the preferable range of the amount of the organic solvent also varies depending on the coating method. For example, in the case of spin coating, the amount of organic solvent is preferably 80 to 85% by mass, which is near the lower limit of the preferred range of the amount of organic solvent, and in the case of slit coating, the amount of organic solvent is preferably 99.0 to 99.9% by mass, which is near the upper limit of the preferred range of the amount of organic solvent.

The second resin composition solution for an antireflection layer of the present invention has a typical composition, which is a resin composition solution containing a thermosetting resin composition and an organic solvent,
the thermosetting resin composition contains 25 to 85 mass% of silica particles having a refractive index of 1.2 to 1.8 and an average particle size of 30 to 220 nm and dispersible in the organic solvent, based on the entire resin composition; 12 to 74.26 mass% of an epoxy compound, based on the entire resin composition; and 1 to 25 mass parts of a heat curing agent, based on 100 mass parts of the epoxy compound; the content of the organic solvent is 80 to 99.9 mass% based on the total amount of the thermosetting resin composition and the organic solvent;
The resin composition solution has a solution viscosity of 1 to 4 mPa·sec.

The resin composition for the light-shielding layer used in the first and second display device substrate manufacturing methods of the present invention contains the light-shielding component and a photocurable resin. The photocurable resin is not particularly limited as long as it is a resin that is cured by light irradiation (for example, UV irradiation), but from the viewpoint of excellent developability, an alkali-soluble photocurable resin is preferred, and from the viewpoint of excellent photocurability and patterning properties, an alkali-soluble resin containing a polymerizable unsaturated group described in JP 2017-72760 A, i.e., an epoxy (meth)acrylate acid adduct obtained by further reacting a reaction product of a compound having two or more epoxy groups (more preferably an epoxy compound obtained by reacting a bisphenol with an epihalohydrin) and (meth)acrylic acid (meaning "acrylic acid and/or methacrylic acid") with a polyvalent carboxylic acid or its acid anhydride, is preferred, and an epoxy acrylate acid adduct derived from a bisphenol fluorene compound is particularly preferred.

In such a resin composition for a light-shielding layer, the content of the light-shielding component is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and particularly preferably 30 to 70% by mass, based on the entire resin composition for a light-shielding layer. The content of the photocurable resin is preferably 5.54 to 90% by mass, more preferably 11.7 to 80% by mass, and particularly preferably 17.8 to 70% by mass, based on the entire resin composition for a light-shielding layer. If the content of the light-shielding component is less than the lower limit (or if the content of the photocurable resin exceeds the upper limit), the light-shielding properties of the formed light-shielding layer tend to decrease, while if the content of the light-shielding component exceeds the upper limit (or if the content of the photocurable resin is less than the lower limit), the surface smoothness of the formed light-shielding layer and the dispersion stability of the light-shielding component tend to decrease.

In addition, such a resin composition for a light-shielding layer may contain a photopolymerizable monomer. This makes it possible to optimize the sensitivity when the light-shielding layer is optically processed, and to optimize the mechanical properties of the film, such as the surface hardness, of the light-shielding layer that is formed. Examples of such photopolymerizable monomers include photopolymerizable monomers having at least one ethylenically unsaturated bond (e.g., (meth)acrylic acid esters having at least one ethylenically unsaturated bond) described in JP 2017-72760 A. The content of such photopolymerizable monomers is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, and particularly preferably 3 to 10% by mass, based on the total amount of the photocurable resin and the photopolymerizable monomer.

Furthermore, the resin composition for the light-shielding layer preferably contains a photopolymerization initiator. Such photopolymerization initiators are not particularly limited, and examples thereof include the photopolymerization initiators described in JP 2017-72760 A, among which oxime ester-based polymerization initiators are particularly preferred. The content of such photopolymerization initiators can be appropriately set according to the photocurability of the resin composition for the light-shielding layer, and is preferably 0.3 to 30 parts by mass, and more preferably 1 to 25 parts by mass, per 100 parts by mass of the total amount of the photocurable resin and the photopolymerizable monomer.

In addition, when the heat resistance of the transparent substrate is low and the heat treatment (post-baking) after development is performed at a low temperature such as 150°C or less, it is preferable that the resin composition for the light-shielding layer contains an azo-based polymerization initiator. This improves the thermal radical polymerizability of the resin composition for the light-shielding layer during heating after development (post-baking). There are no particular limitations on such azo-based polymerization initiators, and examples of such azo-based polymerization initiators include the azo-based polymerization initiators described in JP-A-2017-181976. There are no particular limitations on the content of such azo-based polymerization initiators, and the content can be appropriately set depending on the thermal radical polymerizability of the resin composition for the light-shielding layer, etc.

Furthermore, the resin composition for the light-shielding layer may contain various additives, such as dispersants, polymerization initiators other than the photopolymerization initiators and azo-based polymerization initiators, chain transfer agents, sensitizers, non-photosensitive resins, curing agents, curing accelerators, antioxidants, plasticizers, fillers, coupling agents, surfactants, color-adjusting pigments, and dyes, as necessary.

The resin composition for the light-shielding layer is preferably used in the form of a solution (i.e., as a solution of the resin composition for the light-shielding layer). This allows a uniform layer of the resin composition for the light-shielding layer to be formed. The organic solvent used in the resin composition solution for the light-shielding layer is not particularly limited, and examples thereof include the solvents described in JP-A-2017-72760. It is preferable to mix such an organic solvent so that the amount of the organic solvent is 60 to 90% by mass relative to the total amount of the resin composition for the light-shielding layer and the organic solvent, and it is more preferable to mix such that the solution viscosity of the resin composition for the light-shielding layer solution (B-type or E-type viscometer) is 1 to 30 mPa·sec.

In the first method for manufacturing a display device substrate of the present invention, first, a layer made of the first antireflection layer resin composition (hereinafter referred to as the "first antireflection layer resin composition layer") is formed on the transparent substrate.

The average thickness of the resin composition layer for the first antireflection layer is 0.01 to 1 μm. If the average thickness of the resin composition layer for the first antireflection layer is less than the lower limit, the surface roughness of the resin composition layer for the first antireflection layer tends to exceed the upper limit of the predetermined range, and if the average thickness exceeds the upper limit, the surface roughness of the resin composition layer for the first antireflection layer tends to be less than the lower limit of the predetermined range. The average thickness of the resin composition layer for the first antireflection layer is preferably 0.02 to 0.5 μm, more preferably 0.04 to 0.3 μm, from the viewpoint that the surface roughness of the resin composition layer for the first antireflection layer is likely to be within the predetermined range. The average thickness of the resin composition layer for the first antireflection layer can be obtained by measuring the step between the surface of the resin composition layer for the first antireflection layer and the surface of the transparent substrate using a stylus-type step shape measuring device and averaging the steps.

The surface roughness of the first antireflection layer resin composition layer is 40 to 200 nm. If the surface roughness of the first antireflection layer resin composition layer is less than the lower limit, the reflectance of the obtained light-shielding film is not sufficiently reduced, and the reflection of light at the light-shielding film cannot be sufficiently prevented. On the other hand, if the surface roughness of the first antireflection layer resin composition layer exceeds the upper limit, it becomes difficult to achieve a desired level of flatness of the obtained light-shielding film. The surface roughness of such a first antireflection layer resin composition layer is preferably 50 to 180 nm, more preferably 80 to 160 nm, from the viewpoints of reducing the reflectance of the obtained light-shielding film, suppressing the reflection of light at the light-shielding film, and ensuring the flatness of the light-shielding film. The surface roughness of the resin composition layer for the first antireflection layer can be determined by measuring the uneven shape of the surface of the resin composition layer for the first antireflection layer using a stylus-type step shape measuring device to obtain a roughness curve, and then determining the arithmetic average value of roughness for 0.1 mm portions randomly selected from the roughness curve, and using this as the surface roughness of the resin composition layer for the first antireflection layer.

As a method for forming such a first antireflection layer resin composition layer, for example, a method in which the first antireflection layer resin composition solution is applied onto the transparent substrate, and then the organic solvent is removed by performing a heat treatment (pre-baking) can be mentioned.

Next, a layer made of the resin composition for the light-shielding layer (hereinafter referred to as the "resin composition layer for the light-shielding layer") is formed on the first resin composition layer for the antireflection layer thus formed. As a method for forming such a resin composition layer for the light-shielding layer, for example, a method of applying the resin composition solution for the light-shielding layer onto the first resin composition layer for the antireflection layer, and then performing a heat treatment (pre-bake) to remove the organic solvent can be mentioned.

Methods for applying the resin composition solution for the first antireflection layer and the resin composition solution for the light-shielding layer include, for example, the well-known solution immersion method, spray method, and methods using a roller coater, land coater, slit coater, spin coater, etc. The heating temperature and heating time in the pre-bake can be appropriately set according to the type of organic solvent used, etc., and for example, the heating temperature can be set to 60 to 110°C (set so as not to exceed the heat resistance temperature of the transparent substrate) and the heating time can be set to 1 to 3 minutes.

Next, the first antireflection layer resin composition layer and the light-shielding layer resin composition layer thus formed are subjected to a collective exposure process using a desired light-shielding film pattern forming mask, and the photocurable transparent resin in the light-sensitive portion (exposed portion) of the first antireflection layer resin composition layer and the photocurable resin in the light-sensitive portion (exposed portion) of the light-shielding layer resin composition layer are photocured. The exposure process conditions can be appropriately set depending on the type of photocurable resin and photopolymerization initiator used, etc.

Next, the first antireflection layer resin composition layer and the light-shielding layer resin composition layer after exposure are subjected to a development process at the same time to remove the resin composition in the unexposed parts of the first antireflection layer resin composition layer and the light-shielding layer resin composition layer, thereby simultaneously forming an antireflection layer containing the inorganic filler and a transparent resin cured product (cured product of the first antireflection layer resin composition) and a light-shielding layer containing the light-shielding component and a resin cured product (cured product of the light-shielding layer resin composition). Furthermore, in order to sufficiently cure the antireflection layer and the light-shielding layer or to sufficiently remove the developing solution to improve the adhesion between the transparent substrate and the antireflection layer, a heat treatment (post-bake) is performed on the antireflection layer and the light-shielding layer, thereby obtaining a display device substrate of the present invention having a light-shielding film (light-shielding film pattern) consisting of the antireflection layer and the light-shielding layer on the transparent substrate.

The developing method is not particularly limited, and a known developing method can be used. The developing conditions can be appropriately set according to the types of photocurable transparent resin and photocurable resin used. In addition, when the photocurable transparent resin in the resin composition layer for the first antireflection layer and the photocurable resin in the resin composition layer for the light-shielding layer are alkali-soluble, it is preferable to carry out the developing process (alkaline developing process) using an alkaline developer. As the alkaline developer, a known alkaline developer such as an aqueous solution of carbonate or hydroxide of an alkali metal or alkaline earth metal can be used.

The heating temperature and heating time in the post-bake can be set appropriately depending on the type of transparent substrate and resin composition used. For example, when using a transparent substrate with sufficient heat resistance such as a glass substrate, the heating temperature can be set to 180 to 250°C and the heating time can be set to 20 to 60 minutes.

The average thickness of the light-shielding layer thus formed is 0.1 to 30 μm. If the average thickness of the light-shielding layer is less than the lower limit, the light-shielding property is reduced, whereas if the average thickness exceeds the upper limit, the time required for the alkaline development is increased, resulting in reduced productivity. From the viewpoint of achieving both light-shielding property and productivity, the average thickness of the light-shielding layer is preferably 0.5 to 20 μm, more preferably 1 to 10 μm. The average thickness of the light-shielding layer can be determined by measuring the step between the light-shielding layer surface and the transparent substrate surface using a stylus-type step shape measuring device, averaging the steps to determine the average thickness of the light-shielding film consisting of the antireflection layer and the light-shielding layer, and subtracting the average thickness of the first antireflection layer resin composition layer from the average thickness of the light-shielding film.

In this way, in the first method for manufacturing a display device substrate of the present invention, since a photocurable resin is used for both the first antireflection layer resin composition and the light-shielding layer resin composition, the exposure treatment and development treatment can be performed simultaneously on the first antireflection layer resin composition layer and the light-shielding layer resin composition layer.

On the other hand, in the second method for manufacturing a display device substrate of the present invention, first, the resin composition for the second antireflection layer is subjected to a heat curing treatment on the transparent substrate to form an antireflection layer containing the inorganic filler and a transparent resin cured product (a cured product of the resin composition for the second antireflection layer).

The average thickness of the anti-reflective layer is 0.01 to 1 μm. If the average thickness of the anti-reflective layer is less than the lower limit, the surface roughness of the anti-reflective layer tends to exceed the upper limit of the specified range, and if the average thickness exceeds the upper limit, the surface roughness of the anti-reflective layer tends to be less than the lower limit of the specified range. From the viewpoint that the surface roughness of the anti-reflective layer is likely to be within the specified range, the average thickness of such an anti-reflective layer is preferably 0.02 to 0.5 μm, and more preferably 0.04 to 0.3 μm. The average thickness of the anti-reflective layer can be determined by measuring the step between the anti-reflective layer surface and the transparent substrate surface using a stylus-type step shape measuring device and averaging the steps.

The surface roughness of the anti-reflection layer is 40 to 200 nm. If the surface roughness of the anti-reflection layer is less than the lower limit, the reflectance of the resulting light-shielding film is not sufficiently reduced, and the reflection of light at the light-shielding film cannot be sufficiently prevented. On the other hand, if the surface roughness of the anti-reflection layer exceeds the upper limit, it becomes difficult to achieve a desired level of flatness of the resulting light-shielding film. The surface roughness of such an anti-reflection layer is preferably 50 to 180 nm, more preferably 80 to 160 nm, from the viewpoint of further lowering the reflectance of the resulting light-shielding film, further suppressing the reflection of light at the light-shielding film, and ensuring the flatness of the light-shielding film. The surface roughness of the anti-reflection layer can be determined by measuring the uneven shape of the anti-reflection layer surface using a stylus-type step shape measuring device to obtain a roughness curve, and then calculating the arithmetic average value of roughness for 0.1 mm portions randomly selected from the roughness curve, and using this as the surface roughness of the anti-reflection layer.

One method for forming such an anti-reflection layer is, for example, to apply a solution of the resin composition for the second anti-reflection layer onto the transparent substrate, and then subject the resin composition for the second anti-reflection layer to a heat curing treatment.

Methods for applying the second anti-reflection layer resin composition solution include, for example, the well-known solution immersion method and spray method, as well as methods using a roller coater, land coater, slit coater, spin coater, etc.

The heat curing treatment conditions can be set appropriately depending on the type of transparent substrate and the type of resin composition for the second anti-reflection layer used. For example, when a transparent substrate having sufficient heat resistance such as a glass substrate is used, the heating temperature can be set to 180 to 250°C and the heating time can be set to 20 to 60 minutes.

Next, a layer made of the resin composition for light-shielding layers (hereinafter referred to as a "resin composition layer for light-shielding layers") is formed on the anti-reflection layer thus formed. Examples of a method for forming such a resin composition layer for light-shielding layers include a method in which the resin composition solution for light-shielding layers is applied onto the second resin composition layer for anti-reflection layers, and then the organic solvent is removed by a heat treatment (pre-baking).

Methods for applying the resin composition solution for the light-shielding layer include, for example, the well-known solution immersion method, spray method, and methods using a roller coater, land coater, slit coater, spin coater, etc. The heating temperature and heating time in the pre-bake can be appropriately set according to the type of organic solvent used, etc. For example, the heating temperature can be set to 60 to 110°C (set so as not to exceed the heat resistance temperature of the transparent substrate) and the heating time can be set to 1 to 3 minutes.

Next, the light-shielding layer resin composition layer thus formed is subjected to an exposure process using a desired light-shielding film pattern forming mask, and the photocurable resin in the light-sensitive portion (exposed portion) of the light-shielding layer resin composition layer is photocured. The exposure process conditions can be appropriately set depending on the type of photocurable resin and photopolymerization initiator used, etc.

Next, the exposed resin composition layer for the light-shielding layer is subjected to a development process to remove the resin composition in the unexposed portion of the resin composition layer for the light-shielding layer, thereby forming a light-shielding layer containing the light-shielding component and a cured resin (a cured product of the resin composition for the light-shielding layer). Furthermore, the light-shielding layer is subjected to a heat treatment (post-baking) in order to sufficiently cure the light-shielding layer and sufficiently remove the developing solution, thereby obtaining a display device substrate of the present invention having a light-shielding film (light-shielding film pattern) consisting of the antireflection layer and the light-shielding layer on the transparent substrate.

There are no particular limitations on the developing method, and any known developing method can be used. The developing conditions can be appropriately set depending on the type of photocurable resin used, etc. In addition, when the photocurable resin in the light-shielding layer resin composition layer is alkali-soluble, it is preferable to carry out the developing process (alkaline developing process) using an alkaline developer. As the alkaline developer, known alkaline developers such as aqueous solutions of carbonates or hydroxides of alkali metals or alkaline earth metals can be used.

The heating temperature and heating time for post-baking can be set appropriately depending on the type of transparent substrate and resin composition used, etc.

The average thickness of the light-shielding layer thus formed is 0.1 to 30 μm. If the average thickness of the light-shielding layer is less than the lower limit, the light-shielding properties are reduced, whereas if the average thickness exceeds the upper limit, the time required for the alkaline development is increased, resulting in reduced productivity. From the viewpoint of achieving both light-shielding properties and productivity, the average thickness of such a light-shielding layer is preferably 0.5 to 20 μm, more preferably 1 to 10 μm. The average thickness of the light-shielding layer can be determined by measuring the step between the light-shielding layer surface and the transparent substrate surface using a stylus-type step shape measuring device, averaging the steps to determine the average thickness of the light-shielding film consisting of the antireflection layer and the light-shielding layer, and subtracting the average thickness of the antireflection layer from the average thickness of the light-shielding film.

The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples. The average particle size of the inorganic filler and light-shielding component used in the examples and comparative examples, the average thickness of the antireflection layer (or the resin composition layer for the antireflection layer) and the light-shielding layer, and the surface roughness of the antireflection layer (or the resin composition layer for the antireflection layer) were measured by the following methods.

<Measurement of average particle size of inorganic filler and light-shielding component>
Particles of the inorganic filler or light-shielding component were dispersed in an organic solvent used for the resin composition solution so that the particle concentration was 0.1 to 0.5% by mass. The particle size distribution of the particles in the resulting dispersion was measured by dynamic light scattering using a particle size distribution meter (Otsuka Electronics Co., Ltd.'s "Particle Size Analyzer FPAR-1000"), and the resulting particle size distribution was analyzed by the cumulant method to determine the average particle size (average secondary particle size).

<Measurement of Average Thickness of Antireflection Layer (or Resin Composition Layer for Antireflection Layer)>
Using a stylus-type step shape measuring device ("P-10" manufactured by KLA Tencor Corporation), the step between the glass substrate surface and the antireflection layer surface (or the antireflection layer resin composition layer surface) was measured under conditions of a measurement range of 500 μm, a scanning speed of 50 μm/sec, and a sampling rate of 20 Hz, and the average value was taken as the average thickness of the antireflection layer (or the antireflection layer resin composition layer).

<Measurement of average thickness of light-shielding layer>
Using a stylus-type step shape measuring device ("P-10" manufactured by KLA Tencor Corporation), the step between the glass substrate surface and the light-shielding layer surface was measured under conditions of a measurement range of 500 μm, a scanning speed of 50 μm/sec, and a sampling rate of 20 Hz, and the average value was taken as the average thickness of the light-shielding film consisting of the antireflection layer and the light-shielding layer. The average thickness of the light-shielding layer (=average thickness of the light-shielding film-average thickness of the antireflection layer (or the resin composition layer for the antireflection layer)) was calculated by subtracting the average thickness of the antireflection layer (or the resin composition layer for the antireflection layer) from the average thickness of the light-shielding film.

<Measurement of Surface Roughness of Antireflection Layer (or Resin Composition Layer for Antireflection Layer)>
Using a stylus-type step shape measuring device ("P-10" manufactured by KLA Tencor Corporation), the uneven shape of the antireflection layer surface (or the surface of the resin composition layer for an antireflection layer) was measured under conditions of a measurement range of 500 μm, a scanning speed of 10 μm/sec, and a sampling rate of 100 Hz to obtain a roughness curve, and the arithmetic average value of roughness was obtained for portions of 0.1 mm length randomly sampled on this roughness curve, and this was taken as the surface roughness of the antireflection layer (or the resin composition layer for an antireflection layer). The results are shown in Table 1.

The alkali-soluble photocurable transparent resins used in the Examples and Comparative Examples were synthesized by the following method: The raw materials used in the Synthesis Examples are shown below.
BPFE: Bisphenol fluorene type epoxy compound (9,9-bis(4-hydroxy
Reaction product of phenyl)fluorene with chloromethyloxirane (epoxy equivalent:
250 g/eq).
AA: acrylic acid.
PGMEA: propylene glycol monomethyl ether acetate.
TEAB: tetraethylammonium bromide.
BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride.
THPA: tetrahydrophthalic anhydride.
BzMA: benzyl methacrylate.
DCPMA: dicyclopentanyl methacrylate.
GMA: glycidyl methacrylate.
St: styrene.
AIBN: azobisisobutyronitrile.
TDMAMP: trisdimethylaminomethylphenol.
HQ: Hydroquinone.
TEA: triethylamine.

(Synthesis Example 1)
In a four-neck flask (volume 500 ml) equipped with a reflux condenser, BPFE (114.4 g (0.23 mol)), AA (33.2 g (0.46 mol)), PGMEA (157 g) and TEAB (0.48 g) were charged and reacted at 100 to 105° C. for 20 hours while stirring. Next, BPDA (35.3 g (0.12 mol)) and THPA (18.3 g (0.12 mol)) were added to the reaction product in the flask, and the mixture was stirred at 120 to 125° C. for 6 hours to obtain a resin solution containing a photocurable cardo resin. The solid content of this resin solution was 56.1% by mass, the acid value (solid content equivalent) was 103 mgKOH/g, and the Mw by GPC analysis was 3600.

(Synthesis Example 2)
PGMEA (300 g) was placed in a four-neck flask (volume 1 L) equipped with a reflux condenser, and the gas phase in the flask was replaced with nitrogen, and then the temperature was raised to 120° C. A monomer mixture (a mixed solution obtained by dissolving AIBN (10 g) in a liquid mixture of BzMA (35.2 g (0.20 mol)), DCPMA (77.1 g (0.35 mol)), GMA (49.8 g (0.35 mol)), and St (10.4 g (0.10 mol))) was dropped into the flask from a dropping funnel over 2 hours, and then the mixture was stirred at 120° C. for 2 hours to obtain a copolymer solution.

Next, the gas phase in the flask system was replaced with air, and then AA (24.0 g (95% of glycidyl groups)), TDMAMP (0.8 g) and HQ (0.15 g) were added to the copolymer solution in the flask, and the mixture was stirred at 120°C for 6 hours to obtain a copolymer solution containing polymerizable unsaturated groups.

THPA (45.7 g (90% of the moles of AA added) and TEA (0.5 g) were added to this polymerizable unsaturated group-containing copolymer solution, and the mixture was reacted at 120°C for 4 hours to obtain a resin solution containing a photocurable acrylic resin. The solids concentration of this resin solution was 46% by mass, the acid value (solids equivalent) was 68 mgKOH/g, and the Mw by GPC analysis was 7900.

Further, other components used in the examples and comparative examples are shown below.
(Thermosetting transparent resin)
Epoxy resin: 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol ("EHPE3150" manufactured by Daicel Organic Synthesis Company, Ltd.).
(Photopolymerizable monomer)
DPHA: a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate ("DPHA" manufactured by Nippon Kayaku Co., Ltd.).
(Hardening agent)
TMA: trimellitic acid.
(Polymerization initiator)
OXE02: Ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime) (manufactured by BASF Japan Ltd., "Irgacure OXE02").
(Inorganic filler)
Silica A: fumed silica ("Aerosil" manufactured by Nippon Aerosil Co., Ltd.), refractive index: 1.46, average particle size (distribution measurement: dynamic light scattering method, distribution analysis: cumulant method): 170 nm.
Silica B: organosilica sol ("PMA-ST" manufactured by Nissan Chemical Industries, Ltd.), refractive index: 1.46, average particle size (distribution measurement: dynamic light scattering method, distribution analysis: cumulant method): 20 nm.
(Light-shielding component)
Carbon black: carbon black ("MA14" manufactured by Mitsubishi Chemical Corporation), average particle size (distribution measurement: dynamic light scattering method, distribution analysis: cumulant method): 150 nm.
(Organic solvent)
PGMEA: propylene glycol monomethyl ether acetate.

Example 1
First, a resin composition solution for an antireflection layer was prepared by mixing the resin solution containing the photocurable cardo resin obtained in Synthesis Example 1, silica A, and PGMEA so that the contents of each component were as shown in Table 1. Also, a resin composition solution for a light-shielding layer was prepared by mixing the resin solution containing the photocurable cardo resin obtained in Synthesis Example 1, DPHA, carbon black, OXE02, and PGMEA so that the contents of each component were as shown in Table 1.

Next, the anti-reflection layer resin composition solution was applied onto a glass substrate using a spin coater and heated (pre-baked) at 90°C for 1 minute using a hot plate to form an anti-reflection layer resin composition layer with an average thickness of 80 nm. The surface roughness of this anti-reflection layer resin composition layer was 75 nm.

A solution of the resin composition for the light-shielding layer was applied onto this resin composition layer for the anti-reflection layer using a spin coater, and then heated (pre-baked) at 90°C for 1 minute using a hot plate to form a resin composition layer for the light-shielding layer.

The laminated coating film formed in this manner, consisting of the antireflection layer resin composition layer and the light-shielding layer resin composition layer, was covered with a light-shielding film pattern forming mask with a line/space of 20 μm/20 μm, and was exposed to ultraviolet light of 50 mJ/cm ² using an ultra-high pressure mercury lamp with an i-line intensity of 30 mW/cm ² , and the resin in the photosensitive portion was photocured. After the exposure, the laminated coating film was shower-developed at 24° C. and 1 kgf/cm ² pressure using a 0.04% potassium hydroxide aqueous solution, and after the pattern began to appear, the shower development was continued for another 20 seconds. Thereafter, spray washing was performed at a pressure of 5 kgf/cm ² to remove the unexposed portion of the laminated coating film, and a light-shielding film pattern in which the antireflection layer pattern and the light-shielding layer pattern were laminated in this order was formed on the glass substrate. Then, the light-shielding film pattern was subjected to a heat treatment (post-baking) at 230° C. for 30 minutes using a hot air dryer. The average thickness of the light-shielding layer pattern was 1.3 μm.

(Examples 2 to 3)
A light-shielding film pattern in which an antireflection layer pattern and a light-shielding layer pattern were laminated in this order was formed on a glass substrate in the same manner as in Example 1, except that the blending amounts of the resin solution of the photocurable cardo resin obtained in Synthesis Example 1 and Silica A were changed so that the contents of each component in the resin composition solution for antireflection layer were as shown in Table 1. The surface roughness of the resin composition layer for antireflection layer obtained in Example 2 was 98 nm, and the surface roughness of the resin composition layer for antireflection layer obtained in Example 3 was 142 nm.

Example 4
A light-shielding film pattern in which an antireflection layer pattern and a light-shielding layer pattern were laminated in this order was formed on a glass substrate in the same manner as in Example 3, except that a resin composition layer for an antireflection layer having an average thickness of 40 nm was formed. The surface roughness of the resin composition layer for an antireflection layer obtained in Example 4 was 150 nm.

Example 5
A light-shielding film pattern in which an antireflection layer pattern and a light-shielding layer pattern were laminated in this order was formed on a glass substrate in the same manner as in Example 3, except that a resin composition layer for an antireflection layer having an average thickness of 200 nm was formed. The surface roughness of the resin composition layer for an antireflection layer obtained in Example 5 was 50 nm.

Example 6
A light-shielding film pattern in which an antireflection layer pattern and a light-shielding layer pattern were laminated in this order was formed on a glass substrate in the same manner as in Example 3, except that in the resin composition solution for antireflection layer, the resin solution of the photocurable acrylic resin obtained in Synthesis Example 2 was used instead of the resin solution of the photocurable cardo resin obtained in Synthesis Example 1. The surface roughness of the resin composition layer for antireflection layer obtained in Example 6 was 131 nm.

(Example 7)
First, a resin composition solution for an antireflection layer was prepared by mixing the resin solution of the photocurable cardo resin obtained in Synthesis Example 1, an epoxy resin, TMA, silica A, and PGMEA so that the contents of each component were as shown in Table 1. A resin composition solution for a light-shielding layer was also prepared in the same manner as in Example 1.

Next, the resin composition solution for the anti-reflection layer was applied onto a glass substrate using a spin coater, and then the substrate was subjected to a heat curing treatment at 230°C for 30 minutes using a hot air dryer to form an anti-reflection layer with an average thickness of 80 nm. The surface roughness of this anti-reflection layer was 65 nm.

A resin composition solution for a light-shielding layer was applied onto this anti-reflection layer using a spin coater, and then heated (pre-baked) at 90°C for 1 minute using a hot plate to form a resin composition layer for a light-shielding layer.

The thus formed light-shielding layer resin composition layer was covered with a light-shielding film pattern forming mask with an exposure gap adjusted to 100 μm and a line/space of 20 μm/20 μm, and exposed to ultraviolet light of 50 mJ/cm ² using an ultra-high pressure mercury lamp with an i-line intensity of 30 mW/cm ² to photo-cure the resin in the photosensitive portion. After exposure, the light-shielding layer resin composition layer was shower-developed at 24° C. and 1 kgf/cm ² pressure using a 0.04% potassium hydroxide aqueous solution, and after the pattern began to appear, the shower development was continued for another 20 seconds. Thereafter, spray water washing was performed at a pressure of 5 kgf/cm ² to remove the unexposed portion of the light-shielding layer resin composition layer, and a light-shielding film pattern in which an antireflection layer and a light-shielding layer pattern were laminated in this order was formed on the glass substrate. Thereafter, the light-shielding film pattern was subjected to a heat treatment (post-baking) at 230° C. for 30 minutes using a hot air dryer. The average thickness of the light-shielding layer pattern was 1.3 μm.

(Example 8)
A light-shielding film pattern in which an antireflection layer and a light-shielding layer pattern were laminated in this order was formed on a glass substrate in the same manner as in Example 7, except that in the resin composition solution for antireflection layer, epoxy resin, TMA, silica A and PGMEA were mixed so that the contents of each component were as shown in Table 1. The surface roughness of the antireflection layer obtained in Example 8 was 70 nm.

(Comparative Example 1)
A light-shielding film pattern consisting of only a light-shielding layer pattern was formed on a glass substrate in the same manner as in Example 1, except that no antireflection layer was formed.

(Comparative Example 2)
A light-shielding film pattern in which an antireflection layer pattern and a light-shielding layer pattern were laminated in this order was formed on a glass substrate in the same manner as in Example 1, except that the resin solution of the photocurable cardo resin obtained in Synthesis Example 1 and PGMEA were mixed so that the contents of each component in the resin composition solution for antireflection layer were as shown in Table 1. The surface roughness of the resin composition layer for antireflection layer obtained in Comparative Example 2 was 11 nm.

(Comparative Example 3)
A light-shielding film pattern in which an antireflection layer pattern and a light-shielding layer pattern were laminated in this order was formed on a glass substrate in the same manner as in Example 3, except that silica B having an average particle diameter of 20 nm was used instead of silica A having an average particle diameter of 170 nm. The surface roughness of the resin composition layer for antireflection layer obtained in Comparative Example 3 was 30 nm.

<Light blocking degree (OD value) measurement>
The optical density (OD value) of the obtained glass substrate with the light-shielding film pattern was measured using an optical densitometer ("X-Rite361T(V)" manufactured by Sakata Inx Engineering Corporation), and the optical density (OD value) was corrected with the optical density (OD value) of the glass substrate to obtain the light-shielding degree (OD value) of the light-shielding film. The results are shown in Table 1.

<Reflectance measurement>
The reflectance [%] of the obtained glass substrate with the light-shielding film pattern was measured from the side on which the light-shielding film pattern was not formed, using a spectrophotometer ("UH4150" manufactured by Hitachi High-Tech Science Corporation) under the conditions of a C light source and a 2° visual field. The results are shown in Table 1.

As shown in Table 1, it was confirmed that the light-shielding film pattern having an anti-reflection layer formed by curing a resin composition layer for an anti-reflection layer having a specific surface roughness (Examples 1 to 6) and the light-shielding film pattern having an anti-reflection layer having a specific surface roughness (Examples 7 to 8) had reduced reflectance compared to the light-shielding film pattern without an anti-reflection layer (Comparative Example 1), the light-shielding film pattern in which the anti-reflection layer does not contain an inorganic filler (Comparative Example 2), and the light-shielding film pattern having an anti-reflection layer formed by curing a resin composition layer for an anti-reflection layer having a small surface roughness (Comparative Example 3).

As described above, according to the present invention, it is possible to obtain a light-shielding film in which light reflection is sufficiently suppressed. Therefore, the display device substrate of the present invention has a light-shielding film in which light reflection is sufficiently suppressed, and is therefore useful as a substrate for use in display devices such as liquid crystal displays, touch panels, organic EL displays, and quantum dot displays.

Claims (9)

A substrate for a display device, comprising: a transparent substrate; and an antireflection layer disposed on the transparent substrate, the antireflection layer having an average thickness of 0.01 to 1 μm, the antireflection layer containing an inorganic filler having a refractive index of 1.2 to 1.8 and a transparent resin cured product; and a light-shielding layer disposed on the antireflection layer, the light-shielding layer having an average thickness of 0.1 to 30 μm, the antireflection layer containing at least one light-shielding component selected from the group consisting of an organic black pigment, an inorganic black pigment, and a mixed-color pseudo-black pigment, and a resin cured product, the antireflection layer having a surface roughness of 40 to 200 nm at the interface between the antireflection layer and the light-shielding layer. The display device substrate according to claim 1, characterized in that the inorganic filler has an average particle size of 25 to 300 nm. The display device substrate according to claim 1 or 2, characterized in that the content of the inorganic filler is 5 to 95% by mass relative to the entire anti-reflection layer. A method for manufacturing a substrate for a display device, comprising: a transparent substrate; and a light-shielding film, which is formed on the transparent substrate and is composed of an antireflection layer and a light-shielding layer, the method comprising the steps of:
forming a resin composition layer for an antireflection layer on the transparent substrate, the resin composition layer containing an inorganic filler having a refractive index of 1.2 to 1.8 and a photocurable transparent resin, the resin composition layer having an average thickness of 0.01 to 1 μm and a surface roughness of 40 to 200 nm;
forming a resin composition layer for a light-shielding layer, the resin composition layer containing at least one light-shielding component selected from the group consisting of an organic black pigment, an inorganic black pigment, and a mixed color pseudo-black pigment, and a photocurable resin, on the resin composition layer for an antireflection layer;
a step of simultaneously subjecting the resin composition layer for an antireflection layer and the resin composition layer for a light-shielding layer to an exposure treatment, simultaneously subjecting the resin composition layer for an antireflection layer and the resin composition layer for a light-shielding layer to a development treatment, and further subjecting the resin composition layer to a heat treatment (post-baking) to form an antireflection layer containing the inorganic filler and a transparent cured resin and a light-shielding layer containing the light-shielding component and a cured resin and having an average thickness of 0.1 to 30 μm;
A method for manufacturing a substrate for a display device, comprising: The method for manufacturing a display device substrate according to claim 4, characterized in that the photocurable transparent resin in the antireflection layer resin composition layer and the photocurable resin in the light-shielding layer resin composition layer are both alkali-soluble, and the development treatment is an alkali development treatment. A method for manufacturing a substrate for a display device, comprising: a transparent substrate; and a light-shielding film, which is disposed on the transparent substrate and is composed of an antireflection layer and a light-shielding layer, the method comprising the steps of:
a step of subjecting a resin composition for an antireflection layer, which contains an inorganic filler having a refractive index of 1.2 to 1.8 and at least one of a thermosetting transparent resin and a thermosetting monomer, to a heat curing treatment to form an antireflection layer having an average thickness of 0.01 to 1 μm and a surface roughness of 40 to 200 nm on the transparent substrate;
a step of subjecting a resin composition for a light-shielding layer, which contains at least one light-shielding component selected from the group consisting of an organic black pigment, an inorganic black pigment, and a mixed color pseudo-black pigment, and a photocurable resin, to an exposure treatment, followed by a development treatment, and further a heat treatment (post-baking) to form a light-shielding layer having an average thickness of 0.1 to 30 μm on the antireflection layer;
A method for manufacturing a substrate for a display device, comprising: The method for manufacturing a display device substrate according to claim 6, characterized in that the photocurable resin in the resin composition for the light-shielding layer is alkali-soluble, and the development treatment is an alkali development treatment. A resin composition solution for an antireflection layer, comprising a photocurable resin composition and an organic solvent,
the photocurable resin composition contains 5 to 95 mass % of an inorganic filler having a refractive index of 1.2 to 1.8 and an average particle size of 170 to 300 nm, based on the entire resin composition; 1.54 to 95 mass % of a photocurable transparent resin, based on the entire resin composition; 0 to 50 mass % of a photopolymerizable monomer, based on the total amount of the photocurable transparent resin and the photopolymerizable monomer; and 0 to 30 mass parts of a photopolymerization initiator, based on 100 mass parts of the total amount of the photocurable transparent resin and the photopolymerizable monomer;
the content of the organic solvent is 80 to 99.9% by mass based on the total amount of the photocurable resin composition and the organic solvent;
A resin composition solution for an antireflection layer, the solution having a viscosity of 1 to 4 mPa·sec. A resin composition solution for an antireflection layer, comprising a thermosetting resin composition and an organic solvent,
the thermosetting resin composition contains 5 to 95 mass % of an inorganic filler having a refractive index of 1.2 to 1.8 and an average particle size of 170 to 300 nm, based on the entire resin composition; 3.2 to 94.06 mass % of at least one of a thermosetting transparent resin and a thermosetting monomer, based on the entire resin composition; and 1 to 25 mass parts of a heat curing agent, based on 100 mass parts of the total amount of the thermosetting transparent resin and the thermosetting monomer;
the content of the organic solvent is 80 to 99.9% by mass based on the total amount of the thermosetting resin composition and the organic solvent;
A resin composition solution for an antireflection layer, the solution having a viscosity of 1 to 4 mPa·sec.