JP6337454B2 - Front plate for display device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a display device front plate disposed on the front surface of a display device and a method of manufacturing the same.

  In general, a front plate is provided on the front surface of a display device such as a liquid crystal display device, a plasma display panel, an organic EL display device, or electronic paper to protect the display device. As the front plate, it is known to use a tempered glass substrate from the viewpoint of impact resistance. In such a display device, light is reflected due to a difference in refractive index at the interface between the front plate and air, and visibility is lowered. Therefore, it has been proposed to dispose an antireflection film or an antireflection layer on the outermost surface of the front plate.

Examples of the antireflection film include those obtained by forming an antireflection layer on a transparent substrate such as a TAC film or PET film, and examples of the antireflection layer include a high refractive index layer and a low refractive index layer laminated. The thing which was done is mentioned. Such an antireflection film is attached to the outermost surface of the front plate via an adhesive layer or an adhesive layer.
The antireflection film can be provided with antireflection properties simply by being attached to the front plate. However, since an antireflection film includes a transparent substrate and an adhesive layer or an adhesive layer, the optical design is complicated. Further, since the transparent substrate has waviness, the flatness is lowered and the display quality is deteriorated. Moreover, when sticking an antireflection film, troubles, such as mixing of a foreign material and a bubble, arise and a yield falls. Further, the transmittance is lowered by the transparent substrate and the adhesive layer or the adhesive layer.

On the other hand, examples of the antireflection layer include an inorganic film formed by a dry process such as a sputtering method or a vacuum deposition method. Since such an antireflection layer can be formed on a tempered glass substrate, the problems in the antireflection film can be solved. In addition, an inorganic film has a high film strength, and an antireflection layer having a high surface hardness can be obtained.
However, it is difficult to reduce the refractive index of an inorganic film, and it is common to stack a plurality of high refractive index layers and low refractive index layers alternately. In this case, since a plurality of layers are laminated by a dry process, productivity is lowered and manufacturing costs are increased. In particular, in the case of a front plate used for a display device with a large area, the equipment becomes large and the cost increases. Further, in the case of a dry process, variation occurs in the in-plane distribution of the thickness of the antireflection layer, and the uniformity of antireflection properties is impaired.

  In order to solve such problems, for example, Patent Documents 1 to 5 propose techniques for forming an antireflection layer on the front plate by coating. This is advantageous in terms of productivity and cost.

JP 2012-88683 A JP 2012-88684 A JP2012-150418A JP 2012-189986 A JP 2012-225992 A

  When the antireflection layer is formed by coating, examples of the configuration of the antireflection layer include a configuration in which a high refractive index layer and a low refractive index layer are laminated on a glass substrate. Examples of the high refractive index layer include those containing a binder resin and high refractive index fine particles. As the high refractive fine particles, for example, metal oxide fine particles are used. Examples of the low refractive index layer include those containing a binder resin and low refractive index fine particles. As the low refractive index fine particles, for example, hollow particles or porous particles are used.

  As a method for forming the high refractive index layer, for example, a method of applying and curing a curable resin composition for a high refractive index layer on a glass substrate has been proposed. In this method, the degree of shrinkage differs between the glass substrate and the coating film of the curable resin composition for the high refractive index layer during curing, and the adhesion of the high refractive index layer to the glass substrate may be reduced. Moreover, depending on the kind of the resin component in the curable resin composition for high refractive index layers, the curing reaction may be inhibited by oxygen in the air, and the adhesion of the high refractive index layer to the glass substrate may be reduced. In particular, when the high refractive index layer contains high refractive index fine particles, or when the thickness of the high refractive index layer is thin, the curing reaction tends to be insufficient, and there is a concern that adhesiveness may be reduced. In addition, since the high refractive index fine particles are solid particles, they are more likely to settle than the low refractive index fine particles that are hollow particles or porous particles, and are present at the interface between the high refractive index layer and the glass substrate. In such a case, the adhesion of the high refractive index layer to the glass substrate tends to decrease.

  The present invention has been made in view of the above problems, and provides an inexpensive front plate for a display device that has good adhesion of a high refractive index layer to a glass substrate and is excellent in antireflection properties, and a method for producing the same. The main purpose.

  In order to solve the above problems, the present invention provides a tempered glass substrate, a primer layer formed directly on the tempered glass substrate, a first binder resin and a metal oxide formed directly on the primer layer. A high refractive index layer containing fine particles, and a low refractive index layer formed on the high refractive index layer, containing a second binder resin and refractive index adjusting fine particles, and having a lower refractive index than the high refractive index layer. Provided is a display device front plate.

  According to the present invention, since both the high refractive index layer and the low refractive index layer contain a binder resin, they can be formed by a wet process, and a uniform layer can be easily formed even in a large area. Can do. Therefore, it is possible to obtain an inexpensive front plate for a display device having excellent antireflection properties. According to the present invention, the high refractive index layer is formed on the tempered glass substrate via the primer layer, so that the high refractive index layer contains metal oxide fine particles, and the thickness of the high refractive index layer is further increased. Is relatively thin, it is possible to improve the adhesion of the high refractive index layer to the tempered glass substrate.

  In the said invention, it is preferable that the said 1st binder resin is an ultraviolet curable resin. In UV curable resins, the curing reaction may be inhibited by oxygen in the air. In particular, the high refractive index layer contains metal oxide fine particles, and the thickness of the high refractive index layer is relatively thin. There is a concern that the adhesion of the high refractive index layer may be lowered. On the other hand, in the present invention, since the high refractive index layer is formed on the tempered glass substrate through the primer layer, the adhesion of the high refractive index layer is ensured even when an ultraviolet curable resin is used. can do.

  Moreover, in this invention, the said primer layer may have an unevenness | corrugation in the surface at the side of the said high refractive index layer. This is because the adhesion between the primer layer and the high refractive index layer can be improved.

  The present invention also includes a primer layer forming step in which a primer layer curable resin composition is applied directly on a tempered glass substrate and cured to form a primer layer, and a high refractive index layer directly on the primer layer. Applying a curable resin composition and curing to form a high refractive index layer, and applying and curing the low refractive index layer curable resin composition on the high refractive index layer And providing a low refractive index layer forming step of forming a low refractive index layer having a refractive index lower than that of the high refractive index layer.

  According to the present invention, since the primer layer, the high refractive index layer, and the low refractive index layer are all formed by a wet process, a uniform layer can be easily formed even in a large area. Therefore, it is possible to manufacture a display device front plate having excellent antireflection properties at low cost. Further, according to the present invention, the high refractive index layer is formed on the tempered glass substrate via the primer layer, so that the high refractive index layer contains metal oxide fine particles, and the thickness of the high refractive index layer is relatively Even if it is thin, it is possible to obtain a high refractive index layer having good adhesion to the tempered glass substrate.

  In the said invention, after apply | coating the said curable resin composition for high refractive index layers on the coating film of the said curable resin composition for primer layers in the said primer layer formation process and the said high refractive index layer formation process, You may harden the coating film of the said curable resin composition for primer layers, and the coating film of the said curable resin composition for high refractive index layers. By applying the curable resin composition for the high refractive index layer while the coating film of the curable resin composition for the primer layer is uncured or semi-cured, a high refractive index layer having good adhesion to the primer layer is obtained. Can be obtained.

  In this invention, there exists an effect that the adhesiveness of the high refractive index layer with respect to a tempered glass board | substrate is favorable, and it is possible to provide the cheap front plate for display apparatuses which is excellent in antireflection property.

It is a schematic sectional drawing which shows an example of the front plate for display apparatuses of this invention. It is a schematic sectional drawing which shows the other example of the front plate for display apparatuses of this invention. It is a schematic sectional drawing which shows the other example of the front plate for display apparatuses of this invention. It is process drawing which shows an example of the manufacturing method of the front plate for display apparatuses of this invention.

  Hereinafter, the front plate for a display device and the manufacturing method thereof according to the present invention will be described in detail.

A. Front plate for display device The front plate for display device of the present invention comprises a tempered glass substrate, a primer layer formed directly on the tempered glass substrate, and formed directly on the primer layer. A high refractive index layer containing metal oxide fine particles, and a low refractive index formed on the high refractive index layer, containing a second binder resin and refractive index adjusting fine particles, and having a lower refractive index than the high refractive index layer And a layer.

Here, the “primer layer formed directly on the tempered glass substrate” means that the tempered glass substrate and the primer layer are in direct contact with each other, for example, an adhesive layer or an adhesive layer between the tempered glass substrate and the primer layer. It means that a transparent substrate or the like is not formed.
In addition, the “high refractive index layer formed directly on the primer layer” means that the primer layer and the high refractive index layer are in direct contact with each other, for example, an adhesive layer or the like between the primer layer and the high refractive index layer. It means that an adhesive layer, a transparent substrate and the like are not formed.

The front plate for a display device of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of the front plate for a display device of the present invention. As illustrated in FIG. 1, the front plate 1 for a display device includes a tempered glass substrate 2, a primer layer 3 formed directly on the tempered glass substrate 2, and a high refraction formed directly on the primer layer 3. It has a refractive index layer 4 and a low refractive index layer 5 formed on the high refractive index layer 4. The high refractive index layer 4 contains a first binder resin and metal oxide fine particles, and the low refractive index layer 5 contains a second binder resin and refractive index adjusting fine particles.

In the present invention, since both the high refractive index layer and the low refractive index layer contain a binder resin, they can be formed by a wet process, and a uniform layer can be easily formed even in a large area. it can. Therefore, it is possible to obtain an inexpensive front plate for a display device having excellent antireflection properties.
In the present invention, since the high refractive index layer is formed on the tempered glass substrate through the primer layer, the high refractive index with respect to the tempered glass substrate can be obtained even if the high refractive index layer contains metal oxide fine particles. It is possible to improve the adhesion of the rate layer. Moreover, even when the thickness of the high refractive index layer is relatively thin and the curing reaction is inhibited by oxygen in the air, the adhesion of the high refractive index layer to the tempered glass substrate can be ensured.

  Hereafter, each structure in the front plate for display apparatuses of this invention is demonstrated.

1. Tempered glass substrate The tempered glass substrate in the present invention supports the primer layer, the high refractive index layer, and the low refractive index layer.

Here, “tempered glass” is a glass in which a compressive stress layer is provided on the surface of the glass. The compressive stress layer is formed, for example, by replacing sodium in the glass with potassium. By forming such a compressive stress layer on the surface of the glass, it is possible to prevent the tempered glass substrate from cracking when an impact is applied to the tempered glass substrate.
The thickness of the compressive stress layer is not particularly limited and is appropriately set according to the required characteristics. For example, when it is necessary to ensure the cutting property and productivity of the glass while imparting a certain degree of strength to the glass, the thickness of the compressive stress layer is set within a range of about 5 μm to 10 μm. Moreover, when it is calculated | required to give still higher intensity | strength to glass, the thickness of a compressive-stress layer may be set in the range of about 10 micrometers-35 micrometers, and may be set to 35 micrometers or more. When the thickness of the compressive stress layer is in the range of about 10 μm to 35 μm, the glass has a certain degree of cutability. On the other hand, when the thickness of the compressive stress layer is 35 μm or more, it is difficult to cut the glass even if a high-performance cutting means such as a diamond cutter is used. Therefore, when the thickness of the compressive stress layer is required to be 35 μm or more, the compressive stress layer may be formed on the surface of the glass by performing ion exchange treatment on the glass after being cut into a desired shape. preferable.
Examples of the glass having a compressive stress layer formed on the surface in this way include Corning's Gorilla Glass (Gorilla Glass) and Asahi Glass Company's Dragon Trail.

  As a material of the tempered glass substrate, for example, chemically tempered glass can be used, and it is appropriately selected according to light transmittance, durability and the like.

  The thickness of the tempered glass substrate is not limited as long as it can be used as a front plate for a display device, depending on the strength required for the front plate for a display device, the dimensions of the display device in which the front plate for a display device is used, and the like. For example, within a range of 0.1 mm to 1.5 mm.

  Here, the “thickness” of each member refers to a thickness obtained by a general measurement method. Thickness measurement methods include, for example, a stylus type method of calculating the thickness by tracing the surface with a stylus and detecting an unevenness, an optical method of calculating the thickness based on the spectral reflection spectrum, etc. Can do. Specifically, the thickness can be measured using a stylus thickness meter P-15 manufactured by KLA-Tencor Corporation. In addition, as thickness, the average value of the thickness measurement result in the several location of the member used as object may be used.

2. Primer layer The primer layer in the present invention is directly formed on the tempered glass substrate. By forming the primer layer, the adhesion of the high refractive index layer to the tempered glass substrate can be enhanced.

  The refractive index of the primer layer is preferably not less than the refractive index of the tempered glass substrate and not more than the refractive index of the high refractive index layer. Further, the refractive index of the primer layer is preferably such that the difference from the refractive index of the tempered glass substrate is small or the difference from the refractive index of the high refractive index layer is small. It is preferable that the difference from the refractive index of the high refractive index layer is within 0.03 or within 0.03. In particular, it is preferable that the refractive index of the primer layer has a small difference from the refractive index of the tempered glass substrate. Specifically, when the refractive index of the tempered glass substrate is 1.51, the refractive index of the primer layer is preferably in the range of 1.51 to 1.54. In this case, reflection of light at the interface between the primer layer and the tempered glass substrate can be suppressed.

  Here, the “refractive index” of each member refers to the refractive index with respect to light having a wavelength of 550 nm. The method for measuring the refractive index is not particularly limited, and examples thereof include a method of calculating from a spectral reflection spectrum, a method of measuring using an ellipsometer, and an Abbe method. An example of the ellipsometer is UVSEL manufactured by Joban-Evon. Specifically, the refractive index can be measured with DF1030R manufactured by Techno Synergy.

The material of the primer layer is particularly limited as long as it has adhesion to the tempered glass substrate and the high refractive index layer, has light transmittance, and can obtain a primer layer satisfying the above refractive index. Is not to be done. Examples thereof include thermosetting resins and ionizing radiation curable resins such as ultraviolet curable resins and electron beam curable resins. Specifically, the same thing as the 1st binder resin used for the below-mentioned high refractive index layer and the 2nd binder resin used for a low refractive index layer is mentioned.
Moreover, the primer layer may contain various additives, such as a polymerization initiator, as needed.

  Further, as illustrated in FIG. 2, the primer layer 3 may have irregularities on the surface on the high refractive index layer 4 side. Thereby, the adhesiveness of a primer layer and a high refractive index layer can be improved. The height difference and the pitch of the unevenness may be adjusted as appropriate as long as the adhesiveness with the high refractive index layer can be enhanced. The irregularities may be regularly arranged or irregularly arranged.

  The thickness of the primer layer is not particularly limited as long as it can increase the adhesion of the high refractive index layer to the tempered glass substrate. For example, the adhesion between the tempered glass substrate and the high refractive index layer can be enhanced by making the primer layer thicker than the high refractive index layer. Specifically, from the viewpoint of adhesion, the thickness of the primer layer is preferably in the range of 0.5 μm to 3.5 μm. On the other hand, when the primer layer is thick, the hardness and strength of the front plate for a display device of the present invention may decrease. Therefore, from the viewpoint of hardness and strength, the primer layer is preferably relatively thin in the above range.

Examples of the method for forming the primer layer include a method in which a curable resin composition for a primer layer is applied on a tempered glass substrate and cured.
The method for forming the primer layer is described in “B. Method for producing front plate for display device”, and thus the description thereof is omitted here.

3. High Refractive Index Layer The high refractive index layer in the present invention is formed directly on the primer layer, has a higher refractive index than the low refractive index layer, and contains the first binder resin and metal oxide fine particles.

  The refractive index of the high refractive index layer may be higher than the refractive index of the low refractive index layer and higher than the refractive index of the tempered glass substrate. The refractive index of the tempered glass substrate is 1.51, for example. Specifically, the refractive index of the high refractive index layer is preferably in the range of 1.5 to 1.7.

  The first binder resin used for the high refractive index layer is not particularly limited as long as it has optical transparency and can obtain a high refractive index layer satisfying the above refractive index. It is appropriately selected from the viewpoints of film properties and film strength. Among these, the first binder resin is preferably a cured resin that is cured by irradiation with ionizing radiation such as heat, ultraviolet rays, or electron beams. Examples of the curable resin include a thermosetting resin and an ionizing radiation curable resin. Among these, ionizing radiation curable resins are preferable. This is because the surface hardness of the high refractive index layer can be increased.

  Here, “ionizing radiation curable resin” refers to a resin cured by irradiation with ionizing radiation. “Ionizing radiation” refers to electromagnetic waves or charged particle beams having an energy quantum capable of polymerizing or cross-linking molecules. For example, in addition to ultraviolet rays and electron beams, electromagnetic waves such as X rays and γ rays, α rays And charged particle beams such as ion beams.

  Examples of the ionizing radiation curable resin include an ultraviolet curable resin and an electron beam curable resin. Among these, an ultraviolet curable resin is preferable. In the case of an ultraviolet curable resin or an electron beam curable resin, the curing reaction may be inhibited by oxygen in the air. In particular, since the high refractive index layer contains metal oxide fine particles and is relatively thin, the curing reaction tends to be insufficient, and there is a concern that the adhesion may be lowered. In contrast, in the present invention, since the primer layer is formed under the high refractive index layer, adhesion can be ensured even when an ultraviolet curable resin or an electron beam curable resin is used.

  Specifically, examples of the first binder resin include those used in the high refractive index layer described in JP2013-142817A, JP2012-150226A, JP2011-170208A, and the like. be able to.

The metal oxide fine particles are not particularly limited as long as a high refractive index layer satisfying the above-described refractive index can be obtained, and among them, the metal oxide fine particles have a refractive index of 1.5 to 2. It is preferably about 8.
Examples of such metal oxide fine particles include zirconium oxide (ZrO ₂ , refractive index: 2.10), antimony oxide (Sb ₂ O ₅ , refractive index: 2.04), antimony tin oxide (ATO, refractive). Ratio: 1.75 to 1.95), indium tin oxide (ITO, refractive index: 1.95 to 2.00), phosphorus tin compound (PTO, refractive index: 1.75 to 1.85), gallium zinc Oxide (1.90 to 2.00), β-Al ₂ O ₅ (refractive index: 1.63 to 1.76), γ-Al ₂ O ₅ (refractive index: 1.63 to 1.76), BaTiO ₃ (refractive index: 2.4), ZnSb ₂ O ₆ (refractive index: 1.9 to 2.0), titanium oxide (TiO ₂ , refractive index: 2.71), cerium oxide (CeO 2, refractive index: 2.20), tin oxide (SnO ₂ , refractive index: 2.00), aluminum Zinc oxide (AZO, refractive index: 1.90 to 2.00), gallium zinc oxide (GZO, refractive index: 1.90 to 2.00), zinc antimonate (ZnSb ₂ O ₆ , refractive index: 1 .90 to 2.00).

Further, the metal oxide fine particles may be subjected to a surface treatment. By subjecting the metal oxide fine particles to surface treatment, the affinity with the first binder resin and the solvent is improved, the dispersion of the metal oxide fine particles becomes uniform, and the metal oxide fine particles are less likely to aggregate. Decrease in light transmittance of the refractive index layer, applicability of the curable resin composition for high refractive index layer, and reduction in coating strength of the curable resin composition for high refractive index layer can be suppressed.
Examples of the surface-treated metal oxide fine particles include those described in JP2013-142817A.

  The metal oxide fine particles may be reactive fine particles having a photocurable group on the surface thereof.

The average particle diameter of the metal oxide fine particles is not limited as long as a high refractive index layer having a uniform thickness can be formed. For example, it is preferably in the range of 5 nm to 200 nm, and more preferably in the range of 5 nm to 100 nm. In particular, it is preferably within the range of 10 nm to 80 nm. When the average particle diameter of the metal oxide fine particles is within the above range, the light transmittance of the high refractive index layer is not impaired, and a good dispersion state of the metal oxide fine particles can be obtained. If the average particle diameter of the metal oxide fine particles is within the above range, the average particle diameter may be either the primary particle diameter or the secondary particle diameter, and the metal oxide fine particles are connected in a chain. May be.
Here, the average particle diameter of the metal oxide fine particles refers to an average value of 20 particles observed by a transmission electron microscope (TEM) photograph of a cross section of the high refractive index layer.

  The shape of the metal oxide fine particles is not particularly limited, and examples thereof include a spherical shape, a chain shape, and a needle shape.

  The contents of the first binder resin and the metal oxide fine particles in the high refractive index layer are appropriately set so that the refractive index of the high refractive index layer as a whole satisfies the above refractive index.

  When an ultraviolet curable resin is used as the ionizing radiation curable resin, the high refractive index layer may contain a photopolymerization initiator. As a photoinitiator, it can select from a general thing suitably.

  The high refractive index layer may contain various additives according to desired physical properties. Examples of additives include a dispersion aid, a weather resistance improver, an abrasion resistance improver, a polymerization inhibitor, a crosslinking agent, an infrared absorber, an adhesion improver, an antioxidant, a leveling agent, a thixotropic agent, and a cup. A ring agent, a plasticizer, an antifoamer, a filler, etc. are mentioned.

  The thickness of the high refractive index layer varies depending on the refractive index, but is preferably in the range of 50 nm to 200 nm. When the thickness of the high refractive index layer is thin as described above, the curing reaction may be inhibited by oxygen in the air depending on the type of the first binder resin contained in the high refractive index layer. In such a case, there is a concern about a decrease in adhesion. On the other hand, in the present invention, since the primer layer is formed under the high refractive index layer, adhesion can be ensured even if the high refractive index layer is thin.

As a formation method of a high refractive index layer, the method of apply | coating and hardening the curable resin composition for high refractive index layers on a primer layer is mentioned.
In addition, since the formation method of a high refractive index layer is described in "B. Manufacturing method of front plate for display device", description here is abbreviate | omitted.

4). Low Refractive Index Layer The low refractive index layer in the present invention has a refractive index lower than that of the high refractive index layer, and contains the second binder resin and refractive index adjusting fine particles.

  The refractive index of the low refractive index layer may be lower than the refractive index of the high refractive index layer and lower than the refractive index of the tempered glass substrate. Specifically, the refractive index of the low refractive index layer is preferably in the range of 1.3 to 1.4.

  The second binder resin used for the low refractive index layer is not particularly limited as long as it has light transmittance and can obtain a low refractive index layer satisfying the above refractive index. It is appropriately selected from the viewpoints of film properties and film strength. For example, examples of the second binder resin include a cured resin cured by irradiation with ionizing radiation such as heat, ultraviolet rays, or electron beams. Examples of the curable resin include a thermosetting resin and an ionizing radiation curable resin. Among these, ionizing radiation curable resins are preferable. This is because the surface hardness of the low refractive index layer can be increased. Further, as the ionizing radiation curable resin, for example, an ultraviolet curable resin or an electron beam curable resin can be used. Among these, an ultraviolet curable resin is preferable.

  Specifically, as the second binder resin, JP2013-142817A, JP2012-150226A, JP2011-170208A, JP2009-86360A, JP2008-9347A. And the like used in the low refractive index layer described in the above.

  The refractive index adjusting fine particles are not particularly limited as long as a low refractive index layer satisfying the above refractive index can be obtained, and either inorganic or organic can be used. Among these, hollow particles and porous particles are preferably used because of their low refractive index. Examples of the hollow particles and the porous particles include porous silica particles, hollow silica particles, porous polymer particles, and hollow polymer particles.

Further, the refractive index adjusting fine particles may be subjected to a surface treatment. By subjecting the refractive index adjusting fine particles to surface treatment, the affinity with the second binder resin and the solvent is improved, the dispersion of the refractive index adjusting fine particles becomes uniform, and aggregation of the refractive index adjusting fine particles is less likely to occur. Decrease in light transmittance of the refractive index layer, applicability of the curable resin composition for low refractive index layer, and reduction in coating strength of the curable resin composition for low refractive index layer can be suppressed.
Examples of the surface-treated refractive index adjusting fine particles include those described in JP2013-142817A and JP2008-9348A.

  The refractive index adjusting fine particles may be reactive fine particles having a photocurable group on the surface thereof.

  Specifically, as the refractive index adjusting fine particles, JP2013-142817A, JP2012-150226A, JP2011-170208A, JP2009-86360A, JP2008-9347A. And the like used in the low refractive index layer described in the above.

The average particle diameter of the refractive index adjusting fine particles is not limited as long as a low refractive index layer having a uniform thickness can be formed. For example, it is preferably within a range of 5 nm to 200 nm, and more preferably within a range of 5 nm to 100 nm. In particular, it is preferably within the range of 10 nm to 80 nm. If the average particle diameter of the refractive index adjusting fine particles is within the above range, the light transmittance of the low refractive index layer is not impaired, and a good dispersion state of the refractive index adjusting fine particles can be obtained. If the average particle diameter of the refractive index adjusting fine particles is within the above range, the average particle diameter may be either the primary particle diameter or the secondary particle diameter, and the refractive index adjusting fine particles are connected in a chain. May be.
Here, the average particle diameter of the refractive index adjusting fine particles refers to an average value of 20 particles observed by a transmission electron microscope (TEM) photograph of a cross section of the low refractive index layer.

  The shape of the refractive index adjusting fine particles is not particularly limited, and examples thereof include a spherical shape, a chain shape, and a needle shape.

  The contents of the second binder resin and the refractive index adjusting fine particles in the low refractive index layer are appropriately set so that the refractive index of the entire low refractive index layer satisfies the above refractive index.

  When an ultraviolet curable resin is used as the ionizing radiation curable resin, the low refractive index layer may contain a photopolymerization initiator. Moreover, the low refractive index layer may contain various additives according to desired physical properties. In addition, about a photoinitiator and various additives, it can be made the same as that of the said high refractive index layer.

  The thickness of the low refractive index layer varies depending on the refractive index, but is preferably in the range of 50 nm to 200 nm from the viewpoint of reducing reflection in the visible light region.

As a formation method of a low refractive index layer, the method of apply | coating and hardening the curable resin composition for low refractive index layers on a high refractive index layer is mentioned.
In addition, since the formation method of a low refractive index layer is described in "B. Manufacturing method of front plate for display apparatus", description here is abbreviate | omitted.

5. Protective layer In the present invention, as exemplified in FIG. 3, a protective layer 6 may be formed on the low refractive index layer 5.
In the present invention, a primer layer is formed to improve adhesion. However, increasing the thickness of the primer layer improves the adhesion, but the hardness and strength of the front plate for the display device are reduced, and the scratch resistance is increased. Tend to deteriorate. On the other hand, by forming a protective layer on the outermost surface of the display device front plate of the present invention, the surface hardness and strength of the display device front plate can be increased, and scratch resistance is improved. Can do.

  The hardness of the protective layer is not particularly limited as long as the desired scratch resistance can be imparted to the display device front plate, but specifically, JIS 5600-5-4 (1999). It is preferable that it is H or more in the pencil hardness test prescribed | regulated.

  The protective layer is not particularly limited as long as it satisfies the above-mentioned hardness, and examples thereof include those containing a resin and those containing a resin and inorganic fine particles.

  The resin used for the protective layer is preferably a thermosetting resin or an ionizing radiation curable resin in order to ensure hardness and strength. Depending on the degree of demand, a thermoplastic resin may be used.

  As thermosetting resin and ionizing radiation curable resin, what is used for the hard-coat thin layer described in Unexamined-Japanese-Patent No. 2003-236970 can be mentioned, for example.

The protective layer is, for example, a cured product of a thermosetting resin composition or an ionizing radiation curable resin composition. A polysiloxane component, specifically, an organic reactive silicon compound may be used in combination with the thermosetting resin composition and the ionizing radiation curable resin composition. When an organic reactive silicon compound is used in combination, the hardness and strength of the coating film are maintained, the slipperiness of the coating film surface is increased, the scratch resistance is improved, and the surface is releasable, thus providing antifouling properties. Has the advantage of improving. In this case, the thermosetting resin composition and the ionizing radiation curable resin composition preferably contain a resin component into which a polar group such as a hydroxyl group, a carboxyl group, an amino group, or an amide group has been introduced. This is because such a resin component forms a covalent bond with the organic reactive silicon compound, and can further improve the hardness and strength of the coating film.
As an organic reactive silicon compound, what is used for the hard-coat thin layer described in Unexamined-Japanese-Patent No. 2003-236970 can be mentioned, for example.

In addition to the organic reactive silicon compound, an organometallic compound represented by the general formula _An MB _xn may be used in combination with the ionizing radiation curable resin composition and the thermosetting resin composition. In the above formula, A represents a hydrolyzable functional group or a hydrocarbon group having a hydrolyzable functional group, M represents a metal atom, and B represents an atomic group covalently or ionically bonded to the metal atom M. Moreover, x in the subscript xn of B represents the valence of the metal atom M, and n, which is also the subscript of A, represents an integer of 2 or more and x or less. Specifically, examples of the organometallic compound include those used for the hard coat thin layer described in JP-A No. 2003-236970.

  Further, urethane acrylate, particularly polyurethane acrylate may be used in combination with the ionizing radiation curable resin composition. In general, acrylates, especially polyfunctional acrylates, give a coating film with excellent hardness, but the impact resistance of the coating film becomes low and may become brittle, but the impact resistance is improved by adding polyurethane acrylate. This is because the coating film becomes flexible.

  As the inorganic fine particles used for the protective layer, fine particles having a relatively high refractive index can be used. Specifically, examples of the inorganic fine particles include those used for the hard coat thin layer described in JP-A No. 2003-236970.

  The protective layer may contain various additives such as a polymerization initiator, an ultraviolet blocking agent, an ultraviolet absorber, and a leveling agent as necessary.

The refractive index of the protective layer is not limited as long as it can obtain a display device front plate having desired antireflection properties, and is preferably in the range of, for example, 1.30 to 1.60. Further, the refractive index of the protective layer is preferably larger than the refractive index of the low refractive index layer, and specifically, larger than the refractive index of the low refractive index layer in the range of 0.14 to 0.28. preferable.
When the refractive index of the protective layer is larger than that of the low refractive index layer, the refractive index difference between the protective layer and air becomes large, and when viewed as a single protective layer, the reflectivity increases, but the primer layer, high refractive index By adjusting the refractive index and the film thickness of the layer and the low refractive index layer, the reflectance can be made equal to the case where there is no protective layer.

  On the other hand, the refractive index of the protective layer may be equal to or lower than the refractive index of the low refractive index layer. By forming a protective layer having a low refractive index on the outermost surface of the display device front plate, reflection of light on the outermost surface of the display device front plate can be reduced.

  The thickness of the protective layer is not particularly limited as long as a front panel for a display device having desired hardness and strength can be obtained, but is preferably ½ or less of the thickness of the low refractive index layer. Specifically, it is preferably in the range of 5 nm to 100 nm. If the thickness of the protective layer is thin, the surface hardness and strength may not be sufficiently obtained. Moreover, when the thickness of the protective layer is thick, the antireflection property may be lowered.

Examples of the method for forming the protective layer include a method in which a curable resin composition for the protective layer is applied on the low refractive index layer and cured.
In addition, since the formation method of a protective layer is described in "B. Manufacturing method of the front plate for display apparatuses", description here is abbreviate | omitted.

6). Applications The front plate for a display device of the present invention can be used for display devices such as a liquid crystal display device, a plasma display panel, an organic EL display device, an inorganic EL display device, and electronic paper. Examples of the use of the front plate for a display device of the present invention include a mobile phone, a tablet terminal, a personal computer, a television, a digital signage, and a wearable terminal. Among them, since the primer layer, the high refractive index layer and the low refractive index layer can be formed by a wet process, a uniform layer can be formed inexpensively and easily even in a large area. The device front plate is suitable for a large-area display device. In particular, a television is preferable, and a large television is more preferable.

7). Manufacturing Method The display device front plate of the present invention is preferably manufactured by a method for manufacturing a display device front plate described below. That is, the primer layer, the high refractive index layer, and the low refractive index layer are preferably formed by a wet process. This is because a uniform layer can be easily and inexpensively formed on a large area tempered glass substrate.

B. Method for producing front plate for display device The method for producing a front plate for display device according to the present invention is a primer layer in which a primer layer curable resin composition is applied directly on a tempered glass substrate and cured to form a primer layer. A high refractive index layer forming step in which a curable resin composition for a high refractive index layer is applied directly on the primer layer and cured to form a high refractive index layer; and on the high refractive index layer And a low refractive index layer forming step of forming a low refractive index layer having a refractive index lower than that of the high refractive index layer by applying and curing a curable resin composition for the low refractive index layer. .

Here, “Apply the primer layer curable resin composition directly on the tempered glass substrate and cure it to form the primer layer” means that the tempered glass substrate and the primer layer are in direct contact and strengthen For example, an adhesive layer, an adhesive layer, a transparent base material or the like is not formed between the glass substrate and the primer layer.
In addition, “applying a curable resin composition for a high refractive index layer directly on the primer layer and curing to form a high refractive index layer” means that the primer layer and the high refractive index layer are in direct contact. For example, an adhesive layer, an adhesive layer, a transparent substrate, or the like is not formed between the primer layer and the high refractive index layer.

A method for producing a front plate for a display device of the present invention will be described with reference to the drawings.
4A to 4C are process diagrams showing an example of a method for manufacturing a display device front plate according to the present invention. First, as shown to Fig.4 (a), the primer layer formation process of apply | coating the curable resin composition for primer layers directly on the tempered glass substrate 2, and making it harden | cure with heat and forming the primer layer 3 is performed. Next, as shown in FIG. 4 (b), the high refractive index layer 4 is formed by directly applying the curable resin composition for the high refractive index layer on the primer layer 3 and curing it by ultraviolet irradiation. A layer forming step is performed. Next, as shown in FIG. 4 (c), a low refractive index layer 5 is formed by applying a curable resin composition for a low refractive index layer on the high refractive index layer 4 and curing it by ultraviolet irradiation. The rate layer forming step is performed.

In the present invention, since all of the primer layer, the high refractive index layer, and the low refractive index layer are formed by a wet process, a uniform layer can be easily formed even in a large area. Therefore, it is possible to manufacture a display device front plate having excellent antireflection properties at low cost.
In the present invention, a high refractive index layer is formed on a tempered glass substrate via a primer layer, so that the high refractive index layer contains metal oxide fine particles, and the high refractive index layer is relatively thin. Even in this case, it is possible to obtain a high refractive index layer having good adhesion to the tempered glass substrate.

  Hereafter, each process in the manufacturing method of the front plate for display apparatuses of this invention is demonstrated.

1. Primer Layer Forming Step In the present invention, a primer layer forming step is performed in which a primer layer curable resin composition is applied directly on a tempered glass substrate and cured to form a primer layer.

  The primer layer curable resin composition contains, for example, a resin component, various additives, and a solvent. The solvent is not particularly limited as long as each component can be dissolved or dispersed, and is appropriately selected.

As a coating method, for example, a method of applying a curable resin composition for a primer layer to the entire area of a tempered glass substrate such as a die coating method, a spin coating method, a dip coating method, or a roll coating method, or a tempered glass substrate such as an inkjet method. Examples thereof include a method for discharging the curable resin composition for the primer layer, a gravure printing method, an offset printing method, a printing method such as a silk screen printing method, and the like.
After application of the primer layer curable resin composition, the primer layer may be dried to remove the solvent.
The curing method varies depending on the type of the resin component, and includes, for example, irradiation with heat, ultraviolet rays or electron beams. When the coating film is cured, an inert gas atmosphere, for example, a nitrogen gas atmosphere is preferably used in order to suppress the inhibition of curing by oxygen.

  Moreover, when forming the primer layer which has an unevenness | corrugation on the surface, for example, after applying and drying the primer layer curable resin composition on a tempered glass substrate, the unevenness forming substrate or the unevenness forming roll is applied to the coating film. And a method of peeling the unevenness forming substrate or the unevenness forming roll, and a method of polishing the primer layer surface.

  Since the other points of the primer layer are described in detail in the above “A. Front plate for display device”, description thereof is omitted here.

2. High refractive index layer forming step In the present invention, a high refractive index layer forming step is performed in which the high refractive index layer curable resin composition is applied directly on the primer layer and cured to form a high refractive index layer. .

  The curable resin composition for a high refractive index layer contains, for example, a resin component, metal oxide fine particles, various additives, and a solvent. The solvent is not particularly limited as long as each component can be dissolved or dispersed. For example, JP 2013-142817 A, JP 2012-150226 A, JP 2011-170208 A, and the like. And those used for forming the high refractive index layer described in (1).

The coating method can be the same as the primer layer forming method.
After application of the curable resin composition for the high refractive index layer, it may be dried to remove the solvent.

  The curing method varies depending on the type of the resin component, and examples thereof include irradiation with ionizing radiation such as heat or ultraviolet rays or electron beams. When the coating film is cured, an inert gas atmosphere, for example, a nitrogen gas atmosphere is preferably used in order to suppress the inhibition of curing by oxygen. Moreover, as curing conditions, for example, conditions described in JP2013-142817A, JP2012-150226A, and the like can be applied.

In the present invention, in the primer layer forming step and the high refractive index layer forming step, the primer layer curable resin composition is applied onto the coating film of the primer layer curable resin composition, and then the primer layer curing is performed. The coating film of the curable resin composition and the coating film of the curable resin composition for the high refractive index layer may be cured. That is, the high refractive index layer curable resin composition may be applied in a state where the coating film of the primer layer curable resin composition is uncured or semi-cured. In this case, a primer layer and a high refractive index layer with good adhesion can be obtained.
In such a case, the difference in the refractive index of the primer layer from the refractive index of the high refractive index layer is preferably small, for example, the difference from the refractive index of the high refractive index layer is preferably within 0.03. .

  Since the other points of the high refractive index layer are described in detail in the above “A. Display device front plate”, description thereof is omitted here.

3. Low refractive index layer forming step In the present invention, a low refractive index having a refractive index lower than that of the high refractive index layer is obtained by applying and curing the curable resin composition for the low refractive index layer on the high refractive index layer. A low refractive index layer forming step of forming a layer is performed.

  The low refractive index layer curable resin composition contains, for example, a resin component, refractive index adjusting fine particles, various additives, and a solvent. The solvent is not particularly limited as long as each component can be dissolved or dispersed. For example, JP 2013-142817 A, JP 2012-150226 A, JP 2011-170208 A, Examples thereof include those used for forming a low refractive index layer described in JP-A-2009-86360, JP-A-2008-9347, and the like.

The method for forming the low refractive index layer can be the same as the method for forming the high refractive index layer.
The other points of the low refractive index layer are described in detail in the above “A. Front plate for display device”, and thus the description thereof is omitted here.

4). Protective layer formation process In this invention, you may perform the protective layer formation process which apply | coats and hardens the curable resin composition for protective layers on the said low refractive index layer, and forms it.
The coating method can be the same as the primer layer forming method.
After application of the curable resin composition for the protective layer, it may be dried to remove the solvent.
Examples of the curing method include irradiation with heat, ionizing radiation such as ultraviolet rays and electron beams.

  In addition, since the other points of the protective layer were described in detail in the above-mentioned “A. Front plate for display device”, description thereof is omitted here.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

Hereinafter, the present invention will be specifically described with reference to examples.
(Preparation)
A front plate for a display device was produced using the following materials.
Tempered glass substrate: Dragontrail (Asahi Glass Co., Ltd.) Size 100mm x 100mm Thickness 0.7mm
Low refractive index layer material: TU2205 (manufactured by JSR, n = 1.35)
High refractive index layer material: KZ6719 (manufactured by JSR, n = 1.65)
KZ6661 (manufactured by JSR, n = 1.60)
Primer layer material: Z7503 (manufactured by JSR, n = 1.51)
Protective layer material: TU2359 (manufactured by JSR, n = 1.37)

[Example 1]
First, using Z7503 made by JSR as the curable resin composition for the primer layer, spin-coating the curable resin composition for the primer layer to a predetermined film thickness on a tempered glass substrate, under an N ₂ atmosphere, The primer layer was formed by exposing for 30 seconds using a high-pressure mercury lamp having an exposure illuminance of 30 mW and drying at 230 ° C. for 20 minutes. Subsequently, KZ6661 made by JSR was used as the curable resin composition for the high refractive index layer, and a high refractive index layer was formed on the primer layer in the same process as the formation of the primer layer. Next, TU2205 manufactured by JSR was used as the curable resin composition for the low refractive index layer, and a low refractive index layer was formed on the high refractive index layer in the same process as the formation of the primer layer. Thereby, a front plate for a display device was obtained.

[Example 2]
A display device front plate was produced in the same manner as in Example 1 except that the thickness of the primer layer was changed.

[Example 3]
A display device front plate was produced in the same manner as in Example 1 except that the thickness of the primer layer was changed.

[Example 4]
A front plate for a display device was produced in the same manner as in Example 1 except that KZ6719 manufactured by JSR was used as the curable resin composition for the high refractive index layer, and the film thickness of the high refractive index layer was changed.

[Example 5]
A low refractive index layer was formed in the same manner as in Example 1 except that the film thicknesses of the high refractive index layer and the low refractive index layer were adjusted. Next, using TU2359 made by JSR as the curable resin composition for the protective layer, a protective layer was formed on the low refractive index layer in the same process as the formation of the primer layer. Thereby, a front plate for a display device was obtained.

[Example 6]
A display device front plate was produced in the same manner as in Example 5 except that the thicknesses of the high refractive index layer, low refractive index layer and protective layer were changed.

[Comparative Example 1]
A front plate for a display device was produced in the same manner as in Example 1 except that the primer layer was not formed and the film thicknesses of the high refractive index layer and the low refractive index layer were adjusted.

[Evaluation]
(Adhesion)
About the front plate for display apparatuses, the adhesiveness of the high refractive index layer with respect to a tempered glass board | substrate was evaluated by the crosscut method based on JISK5600.
A: Peeling area less than 5% B: Peeling area 5% or more and less than 35% C: Peeling area 35% or more

(Looks great)
Black tape was attached to the surface of the front plate for display device on the side of the tempered glass substrate, and the reflectance was measured with an absolute reflectance measuring device VAR-7010 manufactured by JASCO Corporation. The light source was evaluated at D65.
A: Reflectance less than 0.5% B: Reflectance 0.5% or more and less than 1.0% C: Reflectance 1.0% or more

(Pencil hardness)
About the front plate for display devices, the pencil hardness test based on JIS5600-5-4 was done, and the hardness of the surface of the front plate for display devices was measured.
A: 3H or more B: H or more and less than 3H C: Less than H

DESCRIPTION OF SYMBOLS 1 ... Front plate for display apparatuses 2 ... Tempered glass substrate 3 ... Primer layer 4 ... High refractive index layer 5 ... Low refractive index layer 6 ... Protective layer

Claims (4)

A tempered glass substrate;
A primer layer which is an ultraviolet curable resin directly formed on the tempered glass substrate;
A high refractive index layer formed directly on the primer layer and containing a first binder resin that is an ultraviolet curable resin and metal oxide fine particles that are solid particles ;
A low refractive index layer formed on the high refractive index layer, containing a second binder resin and refractive index adjusting fine particles, and having a lower refractive index than the high refractive index layer;
A protective layer formed on the low refractive index layer;
Have
The primer layer has a thickness in the range of 0.5 μm to 3.5 μm,
The thickness of the protective layer is state, and are less than half of the thickness of the low refractive index layer,
The high thickness of the refractive index layer, front plate for a display device according to claim der Rukoto the range of 50 nm to 200 nm. The display device front plate according to claim 1, wherein the primer layer has irregularities on a surface on the high refractive index layer side. A primer layer forming step of directly applying an ultraviolet curable resin composition for a primer layer on a tempered glass substrate, and irradiating and curing the ultraviolet ray to form a primer layer;
A high refractive index layer forming step of directly applying an ultraviolet curable resin composition for a high refractive index layer on the primer layer and irradiating and curing the ultraviolet ray to form a high refractive index layer;
A low refractive index layer forming step of forming a low refractive index layer having a refractive index lower than that of the high refractive index layer by applying and curing a curable resin composition for the low refractive index layer on the high refractive index layer; ,
A protective layer forming step of applying a curable resin composition for a protective layer on the low refractive index layer and curing to form a protective layer;
Have
The primer layer has a thickness in the range of 0.5 μm to 3.5 μm,
The thickness of the protective layer is state, and are less than half of the thickness of the low refractive index layer,
The film thickness of the high refractive index layer is in the range of 50 nm to 200 nm,
Method for manufacturing a display device for a front plate, characterized that you containing metal oxide fine particles wherein the high refractive index layer for an ultraviolet curable resin composition is a first binder resin and solid particles is an ultraviolet curable resin. Wherein the primer layer forming step and the high refractive index layer forming step, after applying the high refractive index layer for an ultraviolet curable resin composition on the coated film of the primer layer for the ultraviolet curable resin composition, wherein the primer layer front panel for a display device according to claim 3, the coating film and the coating film of the high refractive index layer for an ultraviolet curable resin composition of the use ultraviolet curable resin composition characterized in that it is cured by irradiation with ultraviolet light Manufacturing method.

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