JP2017049469A - Front protective plate for display device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front protective plate for a display device which is excellent in antireflection property and capable of preventing the reduction of the sensitivity of an infrared sensor, when used together with the infrared sensor and to provide the display device using the front protective plate for the display device.SOLUTION: There is provided the front protective plate for the display device including a transparent substrate, a decorative layer formed in the outer peripheral part of one surface of the transparent substrate, and an antireflection layer formed in the whole of the other surface of the transparent substrate. An infrared transmission window transmitting infrared light is provided in a decorative area which is an area where the decorative layer is formed. The antireflection layer is made of an organic material or the organic material and fine particles whose average particle diameter is 50nm or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a front protective plate for a display device having an infrared transmission window and a display device using the same.

  In general, a front plate is provided on the front surface of a display device such as a liquid crystal display device, an organic electroluminescence (EL) display device, electronic paper, a smartphone, or a tablet PC (personal computer) to protect the display device. 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. Thus, it has been proposed to dispose an antireflection film or an antireflection layer on the outermost surface of the front plate (Patent Document 1).

  Further, in recent years, touch panels used in combination with display panels in the display devices have been rapidly spread, and multi-functionalization has been promoted such as including various sensors. Specific examples of the various sensors include proximity sensors, illuminance sensors, and composite sensors thereof in smartphones, tablet PCs, and the like having a touch panel function.

The proximity sensor is a sensor that detects the approach of an object, and examples thereof include an infrared sensor. The infrared sensor is composed of a light emitting element that emits infrared light and a light receiving element that receives the infrared light and converts it into an electrical signal, and detects the approach of the face and turns off the display panel during a call with a smartphone. By disabling the touch panel operation, malfunction of the touch panel is prevented (Patent Document 2).
In addition, the infrared sensor is also used for optical wireless data communication using infrared rays in the display device.

JP2012-150418A JP, 2014-099159, A

  However, in the display device provided with the infrared sensor, when the antireflection layer is disposed on the front plate of the display device, there is a problem that the sensitivity of the sensor is lowered.

  The present invention has been made in view of the above-mentioned problems, and is a front protection for a display device that is excellent in antireflection and can prevent a decrease in sensitivity of the infrared sensor when used with an infrared sensor. The main object is to provide a board and a display device using the board.

  As a result of intensive studies to solve the above problems, the present inventors have found that scattering of infrared light due to the particle size (grain boundary) of the constituent material of the antireflection layer is the cause of the above problem. When the constituent material is an inorganic substance, if the particle size is 1/10 or more of the wavelength of the infrared light, the infrared light is scattered and the transmittance of the infrared light is reduced. It has been found that this has led to a decrease in sensitivity.

  In order to solve the above problems, the present invention provides a transparent substrate, a decorative layer formed on the outer peripheral portion of one surface of the transparent substrate, and an antireflection formed on the entire surface of the other surface of the transparent substrate. And an infrared transmission window that transmits infrared light is provided in the decorative region, which is a region in which the decorative layer is formed, and the reflective layer. The prevention layer is provided with an organic material or an organic material and a front protective plate for a display device, which is formed of fine particles having an average particle diameter of 50 nm or less.

  According to the present invention, the antireflection layer is formed of an organic material, or an organic material and fine particles having an average particle diameter of 1/10 or less of the wavelength of infrared light, thereby providing an antireflection function for light in the visible light region. Although it has, the scattering of infrared light is reduced and the transmittance of infrared light is improved, so that the sensitivity of the infrared sensor can be increased.

  In the said invention, the infrared transmission layer which shields visible light and permeate | transmits infrared light may be formed in the area | region in which the said infrared transmission window was formed. This is because by having the infrared transmission layer, it is possible to prevent the infrared sensor from being seen from the outside without reducing the transmittance of infrared light.

  Moreover, in the said invention, the transparent electrode for the position detection of a touch panel may be formed in the surface of the side in which the decorating layer of the said transparent substrate is formed, and the inside of the said decorating area | region. This is because the thickness of the entire display device can be reduced.

  Moreover, this invention has the display element which has the infrared sensor part arrange | positioned in the position facing the said infrared transmission window formed in the said front protection plate for display apparatuses mentioned above, and the said front protection board for display apparatuses. A display device is provided. According to the present invention, an antireflection function can be achieved without reducing the sensitivity of the infrared sensor.

  The front protective plate for a display device of the present invention and the display device using the same are excellent in antireflection properties, and when used together with an infrared sensor, it is possible to prevent a decrease in sensitivity of the infrared sensor. There is an effect.

It is the schematic plan view and XX schematic sectional drawing which show an example of the display apparatus of this invention. It is a schematic sectional drawing which shows an example of the front surface protection plate for display apparatuses of this invention. It is a schematic sectional drawing which shows the other example of the front surface protection plate for display apparatuses of this invention. It is a schematic sectional drawing which shows the other example of the front surface protection plate for display apparatuses of this invention. It is process drawing which shows an example of the manufacturing method of the front surface protection plate for display apparatuses of this invention. It is process drawing which shows the other example of the manufacturing method of the front surface protection plate for display apparatuses of this invention. It is a schematic sectional drawing which shows the other example of the display apparatus of this invention. It is a graph which shows the measurement result of the reflectance in the Example and comparative example of the front surface protection board for display apparatuses of this invention. It is a graph which shows the measurement result of the transmittance | permeability of the infrared light in the Example and comparative example of the front surface protection board for display apparatuses of this invention.

  Hereinafter, the front protective plate for a display device and the display device of the present invention will be described in detail.

A. Front protective plate for display device The front protective plate for display device of the present invention is a transparent substrate, a decorative layer formed on the outer peripheral portion of one surface of the transparent substrate, and the entire surface of the other surface of the transparent substrate. An antireflection layer formed on the front protective plate for a display device, wherein the decorative region, which is the region where the decorative layer is formed, is provided with an infrared transmission window that transmits infrared light. The antireflection layer is formed of an organic material or an organic material and fine particles having an average particle diameter of 50 nm or less.

Conventionally, when the antireflection layer is formed of an inorganic material, there has been a problem that infrared transmittance is reduced. This is presumed to be caused by the fact that crystal grains are formed in the antireflection layer, and that a plurality of thin films having different refractive indexes are laminated.
In general, an inorganic material is likely to be crystallized when an antireflection layer is formed. As the crystallization progresses, a large number of crystal grains are formed, and the interface of crystal grains in the layer increases. Thereby, in the said reflection preventing layer, scattering of infrared light arises and it is thought that it causes the fall of the transmittance | permeability of infrared light.
When the antireflection layer is formed of an inorganic material, it is necessary to stack a plurality of thin films having different refractive indexes in order to obtain desired low reflection characteristics in the visible light region. Generally, by increasing the number of laminated thin films having different refractive indexes, the reflectance at all wavelengths in the visible light region can be reduced to a desired reflectance. Therefore, the wider the wavelength region that is the target for reducing the reflectance, The number of layers increases. As the number of stacked layers increases, light having a wavelength other than the target region is reflected at the interface between the stacked thin films and absorbed into the thin films, so that it is considered that the transmittance of infrared light decreases.
In order to solve such a problem, the present invention has invented a front protective plate for a display device having the above-described antireflection layer.

  According to the present invention, the antireflection layer has an antireflection function for light in the visible region by being formed of an organic material, or an organic material and fine particles having an average particle diameter of 1/10 or less of the wavelength of infrared light. However, the sensitivity of the infrared sensor can be maintained even when an antireflection layer is formed because it can reduce the scattering of infrared light and prevent a decrease in the transmittance of infrared light in the infrared transmission window. Can do.

Hereinafter, the front protective plate for a display device of the present invention will be described with reference to the drawings. FIG. 1 is a schematic plan view (FIG. 1 (a)) and an XX line schematic cross-sectional view (FIG. 1 (b)) showing an example of the front protective plate for a display device of the present invention.
As shown in FIG. 1A, a front protective plate 1 for a display device includes a decorative region 2 formed on the outer periphery, and an infrared transmission window that transmits infrared light to part of the decorative region 2. 3. Moreover, as shown in FIG.1 (b), the front protection plate 1 for display apparatuses of this invention is the transparent substrate 5, the decoration layer 6 formed in the outer peripheral part of the one surface of the said transparent substrate 5, And an antireflection layer 4 formed on the entire surface of the other surface of the transparent substrate 5.
As described above, the front protective plate for a display device of the present invention can prevent a decrease in the transmittance of infrared light in the infrared transmission window, as described above, even when the antireflection layer is formed. The sensitivity of the sensor can be maintained.

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

1. Antireflection Layer The antireflection layer in the present invention is formed on the entire surface of one surface of the transparent substrate, and is formed of an organic material or an organic material and fine particles having an average particle diameter of 50 nm or less.

The antireflection layer has better infrared light transmittance than inorganic materials, and preferably has a visible light reflectance of less than 0.5%, and more preferably less than 0.45%. In particular, it is preferably less than 0.40%.
Further, the transmittance of infrared light in the wavelength region of 800 nm to 1300 nm is preferably 90% or more at all wavelengths in the wavelength region, more preferably 91% or more, particularly 92% or more. It is preferable.

  The antireflection layer is not particularly limited as long as it has the above function, but may have a single-layer structure composed of only a low refractive index layer, or the low refractive index layer and the high refractive index layer may be mutually connected. A multilayer structure formed of a plurality of stacked layers may be used. At this time, a low refractive index layer is usually formed on the most visible side of the plurality of layers.

  The antireflection layer may be formed only from an organic material such as a resin, but may be mixed with refractive index adjusting fine particles having an average particle diameter of 50 nm or less in the organic material such as the resin (hereinafter, It may be an organic layer.) This is because the refractive index can be adjusted without reducing the transmittance of infrared light by mixing the refractive index adjusting fine particles.

  Hereinafter, the low refractive index layer and the high refractive index layer will be described.

(1) Low Refractive Index Layer The low refractive index layer in the present invention is an organic layer, and may have a refractive index lower than that of the high refractive index layer and lower than that of the transparent substrate. Specifically, the refractive index of the low refractive index layer is preferably 1.31-1.35, and more preferably 1.31-1.33.

  The low refractive index layer is not particularly limited as long as the organic layer satisfies the above refractive index and has transparency. For example, the low refractive index layer includes a resin, a binder resin, and low refractive index fine particles. And the like. Among these, since the refractive index can be easily adjusted, the low refractive index layer preferably contains a binder resin and low refractive index fine particles.

  The binder resin used for the low refractive index layer is not particularly limited as long as it satisfies the above refractive index and can obtain a transparent low refractive index layer. It is appropriately selected from the viewpoint of film strength and the like. For example, as the binder resin, a cured resin cured by irradiation with ionizing radiation such as heat or ultraviolet rays or an electron beam can be given. 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.

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.
Specific examples of the binder resin include JP2013-142817A, JP2012-150226A, JP2011-170208A, JP2009-86360A, and JP2008-9347A. The thing used for the low-refractive-index layer currently described can be mentioned.

  The binder resin may be a fluorine resin containing fluorine. This is because antifouling properties can be imparted to the low refractive index layer. Further, the refractive index can be lowered. Moreover, the fluorine resin may contain silicon.

  The low refractive index layer may contain an antifouling agent. As the antifouling agent, a fluorine-based compound or a silicon-based compound can be used. Specifically, examples of the antifouling agent include those described in JP2012-150226A.

  The low refractive index fine particles are particularly limited as long as they are fine particles having an average particle diameter of 50 nm or less, have a refractive index lower than that of the binder resin, and can obtain a low refractive index layer satisfying the above refractive index. Any of inorganic and organic materials 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.

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

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

  Specific examples of the low refractive index fine particles include JP2013-142817A, JP2012-150226A, JP2011-170208A, JP2009-86360A, and JP2008-9347A. And the like used in the low refractive index layer described in the above.

The average particle size of the low refractive index fine particles is not limited as long as it can reduce the scattering of infrared light and improve the transmittance of infrared light. Specifically, it is 50 nm or less. Is preferable, and in particular, it is preferably in the range of 10 nm to 50 nm, and particularly preferably in the range of 30 nm to 50 nm.
As the average particle diameter of the low refractive fine particles decreases, the infrared light transmittance increases. However, in order to obtain a desired low reflection characteristic for visible light, it is necessary to increase the content of the low refractive fine particles. The hardness characteristics of the are reduced. On the other hand, as the average particle diameter of the low refractive fine particles is increased, a desired low reflection characteristic can be obtained with a smaller amount, and the hardness characteristic of the antireflection layer is improved, but the infrared light transmittance is decreased. Therefore, the average particle diameter of the low refractive fine particles is adjusted within the above range from the viewpoint of a balance between desired infrared light transmittance, low reflection characteristics with respect to visible light, and hardness characteristics of the antireflection layer. Is preferred.
Here, the strength characteristics indicate, for example, scratch resistance and rigidity.
If the average particle diameter of the low refractive index fine particles is within the above range, a good dispersion state of the low refractive index fine particles can be obtained without impairing the transparency of the low refractive index layer.
As long as the average particle diameter of the low refractive index fine particles is within the above range, the average particle diameter may be either a primary particle diameter or a secondary particle diameter, or may be chained.
Here, the average particle diameter of the low refractive index 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 low refractive index fine particles is not particularly limited, and examples thereof include a spherical shape, a chain shape, and a needle shape.

  The contents of the binder resin and the low refractive index 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. In the antireflection layer of the present invention, it is preferable that the content of fine particles is low. This is because the strength characteristics of the low antireflection layer can be enhanced.

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

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

  Moreover, although the thickness of the said low refractive index layer changes according to a refractive index, it is preferable to exist in the range of 80 nm-120 nm. Especially, it is preferable to be in the range of 90 nm to 110 nm, and it is particularly preferable to be in the range of 95 nm to 105 nm.

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 is mentioned.
The method for forming the low refractive index layer is described in “6. Manufacturing Method”, and thus the description thereof is omitted here.

(2) High Refractive Index Layer The high refractive index layer in the present invention is an organic layer, as long as the refractive index is higher than that of the low refractive index layer and higher than that of the transparent substrate. Specifically, the refractive index of the high refractive index layer is preferably in the range of 1.55 to 1.65, more preferably in the range of 1.57 to 1.63. , Preferably in the range of 1.59 to 1.61.

  The high refractive index layer is not particularly limited as long as the organic layer satisfies the above refractive index and has transparency. For example, the high refractive index layer contains a resin, a binder resin, and high refractive index fine particles. And the like. Among these, since the refractive index can be easily adjusted, the high refractive index layer preferably contains a binder resin and high refractive index fine particles.

  The binder resin used for the high refractive index layer is not particularly limited as long as it satisfies the above refractive index and can obtain a transparent high refractive index layer. It is appropriately selected from the viewpoint of film strength and the like. For example, as the binder resin, a cured resin cured by irradiation with ionizing radiation such as heat or ultraviolet rays or an electron beam can be given. 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. 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, examples of the binder resin include those used in the high refractive index layer described in JP2013-142817A, JP2012-150226A, and JP2011-170208A. .

The high refractive index fine particles are particularly limited as long as they are fine particles having an average particle diameter of 50 nm or less, have a refractive index higher than that of the binder resin, and can obtain a high refractive index layer satisfying the above refractive index. In particular, the refractive index of the high refractive index fine particles is preferably about 1.5 to 2.8.
Examples of such high refractive index fine particles include metal oxide fine particles, and specifically, zirconium oxide (ZrO ₂ , refractive index: 2.10), antimony oxide (Sb ₂ O ₅ , refraction). Ratio: 2.04), antimony tin oxide (ATO, refractive index: 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 (refractive index: 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), titanium oxide (TiO _2, refractive index: 2.71), cerium oxide (CeO _2, refraction rate: 2.20), tin oxide (SnO _2, refractive index: 2.00), A Miniumu 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).

The high refractive index fine particles may be an organic material, and specific examples include plastic beads described in JP-A-2009-86360.
The high refractive index fine particles may be used singly or in combination of two or more.

The high refractive index fine particles may be surface-treated. For the same reason as the above-mentioned low refractive index fine particles, the transparency of the high refractive index layer is decreased, the coating property of the curable resin composition for the high refractive index layer, the coating film of the curable resin composition for the high refractive index layer. A decrease in strength can be suppressed.
Examples of the surface-treated high refractive index fine particles include those described in JP2013-142817A.

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

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

The average particle diameter of the high-refractive-index fine particles is not limited as long as it can reduce the scattering of infrared light and improve the transmittance of infrared light, and is specifically 50 nm or less. Is preferred. Especially, it is preferable that it exists in the range of 10 nm-50 nm, and it is especially preferable that it exists in the range of 30 nm-50 nm. This is because if the average particle size of the high refractive index fine particles is within the above range, a good dispersion state of the high refractive index fine particles can be obtained without impairing the transparency of the high refractive index layer.
As long as the average particle diameter of the high refractive index fine particles is within the above range, the average particle diameter may be either the primary particle diameter or the secondary particle diameter, or may be chained.
Here, the average particle diameter of the high refractive index 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 high refractive index fine particles is not particularly limited, and examples thereof include a spherical shape, a chain shape, and a needle shape.

  The contents of the binder resin and the high refractive index fine particles in the high refractive index layer are appropriately set so that the refractive index of the entire high refractive index layer 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. Moreover, the high 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 low-refractive-index layer.

  The thickness of the high refractive index layer varies depending on the refractive index, but is preferably in the range of 130 nm to 170 nm. Especially, it is preferable that it exists in the range of 140 nm-160 nm, and it is especially preferable that it exists in the range of 145 nm-155 nm.

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 is mentioned.
The method for forming the high refractive index layer is described in “6. Manufacturing method”, and thus the description thereof is omitted here.

2. Transparent substrate The front protective plate for a display device of the present invention protects the display device when disposed on the entire surface of the display device. Therefore, the transparent substrate in the present invention is preferably a rigid substrate having high rigidity. The rigidity of the transparent substrate may be as long as the display device can be protected.

  The material of the transparent substrate is appropriately selected according to light transmittance, rigidity, strength, durability, etc., for example, alkali glass such as soda glass, borosilicate glass, non-alkali glass, tempered glass, etc. Examples thereof include resins such as glass, polycarbonate, polystyrene, and acrylic. Among these, a tempered glass substrate is preferable. This is because the thickness of the substrate can be reduced because of its excellent mechanical strength.

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.

  The thickness of the transparent substrate in the present invention is not limited as long as it can be used as a front protective plate for a display device. The strength required for the front protective plate for a display device and the display device using the front protective plate for a display device are used. For example, it can be set 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.

3. Decorating layer The decorating layer in this invention is formed in the outer peripheral part of the one surface of the said transparent substrate, and contains an organic material. By forming the decorative layer on the outer periphery, the wiring of the display device, the control circuit, and the like can be hidden, and the design can be improved.

  The said decoration layer will not be specifically limited if it contains an organic material, For example, what contains binder resin and a coloring agent is mentioned.

The colorant used in the decorative layer is appropriately selected according to the target color, and for example, a color pigment such as a black pigment, white pigment, red pigment, yellow pigment, blue pigment, green pigment, purple pigment, etc. Can be used. The color pigments may be used alone or in combination of two or more of the same type or different colors.
Examples of black pigments include carbon black and titanium black.

As binder resin used for a decoration layer, it is suitably selected according to the formation method of a decoration layer.
For example, when the decorative layer is formed by a photolithography method, a photosensitive resin is used as the binder resin. As the photosensitive resin, general ones can be used, for example, photoreactive properties such as reactive vinyl groups such as acrylic resin, epoxy resin, polyimide resin, polyvinyl cinnamate resin, and cyclized rubber. The photosensitive resin which has group is mentioned. A photosensitive resin may be used individually by 1 type, and 2 or more types may be mixed and used for it.

In the case of an acrylic resin, for example, a photosensitive resin composition containing an alkali-soluble resin, a polyfunctional acrylate monomer, a photopolymerization initiator, other additives, and the like can be used as the resin component.
Examples of the alkali-soluble resin include methacrylic acid ester copolymers such as benzyl methacrylate-methacrylic acid copolymer, and cardo resins such as epoxy acrylate having a bisphenol fluorene structure. These may be used alone or in combination of two or more.
Examples of the polyfunctional acrylate monomer include trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like. These may be used alone or in combination of two or more.
In the present invention, (meth) acrylate means either methacrylate or acrylate.
Examples of the photopolymerization initiator include alkylphenone series, oxime ester series, triazine series, and titanate series. These may be used alone or in combination of two or more.
In addition to the above, the photosensitive resin composition can contain various known additives such as a photosensitizer, a dispersant, a surfactant, a stabilizer, and a leveling agent.
Moreover, the color resist used for the colored layer of a color filter can also be used for a decoration layer.

  Moreover, when forming a decoration layer, for example by a printing method, what is used for the above-mentioned high refractive index layer and low refractive index layer can be used as binder resin.

  The color of the decoration layer is not particularly limited, and examples thereof include black, blue, green, red, brown, orange, and white color.

  The decorative layer is preferably disposed in the non-display area when the display device front plate of the present invention is used in a display device. This is because the wiring of the display device and the like can be hidden by the frame-shaped decoration layer, and the design can be improved.

  The thickness of the decoration layer is appropriately selected according to the purpose.

  The decorative layer may be formed directly on the transparent substrate or may be formed via an adhesive layer.

The method for forming the decoration layer is not particularly limited as long as the method can form the decoration layer in a pattern on the transparent substrate.
In addition, since it describes in "6. Manufacturing method" about the formation method of a decoration layer, description here is abbreviate | omitted.

4). Infrared transmissive window The infrared transmissive window in the present invention is a portion that is provided in a decorative region formed in the outer peripheral portion of the front protective plate for a display device, shields visible light, and transmits infrared light. The formation position of the infrared transmission window is not particularly limited as long as it is installed at a position facing the infrared sensor unit when the display device is used.
The shape of the opening of the infrared transmission window is not particularly limited. For example, depending on the size of the sensor to be used and the design of the front surface of the display device, such as an elliptical shape, a circular shape, and a rectangular shape. It can be selected appropriately.
The size of the opening of the infrared transmission window is preferably in the range of 1 mm to 10 mm in major axis, and more preferably in the range of 1 mm to 5 mm when the shape of the opening is elliptical or circular. It is preferable that it is in the range of 2 mm-4 mm especially.
In addition, when the shape of the opening is rectangular, the vertical or horizontal length is preferably in the range of 1 mm to 10 mm, more preferably in the range of 1 mm to 5 mm, especially 2 mm. It is preferably within a range of ˜4 mm.

5). Other Configurations The front protective plate for a display device of the present invention may have other configurations as necessary in addition to the above-described antireflection layer, transparent substrate, decorative layer, and infrared transmission window.

(1) Infrared transmitting layer In the front protective plate for a display device of the present invention, an infrared transmitting layer that blocks visible light and transmits infrared light is formed in the region where the infrared transmitting window is formed. May be. This is because by having the infrared transmission layer, the infrared sensor can be made invisible from the outside without reducing the transmittance of infrared light.

Hereinafter, the front protective plate for a display device having the infrared transmission layer will be described with reference to the drawings. 2 and 3 are schematic cross-sectional views showing other examples of the front protective plate for a display device of the present invention. As shown in FIGS. 2 and 3, the front protective plate 1 for a display device according to the present invention has the infrared transmission layer 7 in addition to the antireflection layer 4, the transparent substrate 5, and the decoration layer 6. It is.
FIG. 2 shows the front protective plate 1 for a display device according to the present invention, which is between the transparent substrate 5 and the decorative layer 6, and the entire region of the decorative region and the region where the infrared transmission window 3 is formed. The example (1st aspect) in which the said infrared transmission layer 7 was formed is shown.
FIG. 3 is an example (second embodiment) in which the infrared transmission layer 7 is formed on the decorative layer 6 in the front protective plate 1 for a display device of the present invention, and the infrared transmission window 3. In this example, the infrared transmission layer 7 is formed only in the region where the light is formed and the periphery thereof.
Hereinafter, each aspect will be described.

(A) 1st aspect The front surface protection plate for display apparatuses of this aspect is an aspect in which the said infrared transmission layer was formed between the said transparent substrate and the said decoration layer.
The infrared transmission layer used in this embodiment is not particularly limited as long as it is a layer that transmits infrared light and blocks visible light. Specifically, the infrared transmittance of the infrared transmission layer depends on specifications, expression color, and infrared components such as an infrared sensor applied to the infrared transmission window, but infrared light in a wavelength region of 800 nm to 1300 nm. Of 90% or more at all wavelengths in the above-mentioned wavelength region, preferably 91% or more, and particularly preferably 92% or more.
Further, the visible light transmittance in the visible light region at a wavelength of 380 nm to 780 nm may be 25% or less, but is preferably 10% or less.

  Moreover, the infrared transmission layer in this aspect is formed in the decoration area | region between the said transparent base material and the said decoration layer, and including the area | region in which the said infrared transmission window was formed at least. In particular, this embodiment is preferably formed in the entire region of the decoration region. It is because it fulfills a function as an anchor layer that improves a decrease in adhesion between the transparent substrate and the decorative layer under high temperature and high humidity.

  The color of the infrared transmission layer is not particularly limited as long as it has the transmittance characteristics as described above, but is usually formed in a color similar to the decorative layer. This is because the infrared transmission window can be made inconspicuous from the outside.

Such an infrared transmission layer is usually formed from a pigment and a binder resin.
Examples of the pigment include diketopyrrolopyrrole-based pigments such as Pigment Red 254 (PR254), anthraquinone-based pigments such as Pigment Red 177 (PR177), and perylene-based red pigments such as Pigment Yellow 139 (PY139). Yellow pigments such as indoline and anthraquinone, for example, blue pigments such as copper phthalocyanine and anthraquinone such as pigment blue PB15: 6 (PB15: 6), and other green pigments such as phthalocyanine and isoindoline, And quinacridone-based purple pigments such as CI Pigment Violet 23 (PV23). In addition, a color pigment exhibiting a hue other than these can also be used.
Here, when the decoration layer is black, it is preferable to use a mixed pigment prepared by mixing a plurality of color pigments such as red, yellow, and blue so as to exhibit a dark color close to black. This is because black pigments such as carbon black may block infrared light.

  The particle diameter of the color pigment is preferably 50 nm or less in terms of average particle diameter, more preferably in the range of 10 nm to 50 nm, and particularly preferably in the range of 30 nm to 50 nm.

The content of the color pigment is preferably in the range of 10% by mass to 60% by mass, for example, in the pigment concentration, and more preferably in the range of 20% by mass to 40% by mass.
When the content of the color pigment is less than the above range, the shielding property against visible light is lowered, so that the film thickness is increased. When the content of the color pigment exceeds the above range, the shielding property against visible light is improved, but the problem that the adhesion property of the infrared transmission layer itself is lowered is not preferable.
The content of the color pigment is expressed as a percentage of the color pigment with respect to the total solid content of the infrared transmission layer.

  Examples of the binder resin used in the infrared transmission layer include photosensitive resins having photoreactive groups such as acrylic resins, epoxy resins, polyimide resins, polyvinyl cinnamate resins, and cyclized rubbers. 1 or more types can be used.

  The infrared transmission layer may contain various additives according to desired physical properties. Examples of the additive include a photosensitizer, a dispersant, a surfactant, a stabilizer, and a leveling agent.

(B) 2nd aspect The infrared transmission layer in this aspect is formed on the decorating layer, Comprising: It forms in the area | region in which the said infrared transmission window was formed at least. In this embodiment, in particular, the infrared transmission layer is preferably formed only in the region where the infrared transmission window is formed and the periphery thereof. This is because the thickness of the front protective plate for the display device can be reduced.

  The infrared transmittance of the infrared transmission layer and the color pigment, binder resin, and the like used in the infrared transmission layer are the same as those described in the first aspect, and are omitted here.

(2) Transparent electrode and wiring In the front protective plate for a display device of the present invention, as shown in FIG. 4, the surface of the transparent substrate 5 on the side where the decorative layer 6 is formed and the inside of the decorative region In addition, a transparent electrode 8 for detecting the position of the touch panel may be formed. This is because the thickness of the entire display device can be reduced.
Furthermore, the wiring 9 connected to the transparent electrode 8 may also be provided on the surface of the decorative layer 6 opposite to the surface facing the transparent substrate. This is because by arranging the wiring 9 in the decoration area of the front protective plate 1 for display device, the wiring or the like can be hidden and the display area can be widened.
Hereinafter, the transparent electrode and the wiring will be described.

(A) Transparent electrode The transparent electrode usually contains a metal oxide.
The metal oxide is not particularly limited as long as it is a general conductive material used for transparent electrodes. For example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide, oxidation Indium, tin oxide, antimony-added tin oxide, fluorine-added tin oxide, aluminum-added zinc oxide, potassium-added zinc oxide, silicon-added zinc oxide, zinc oxide-tin oxide system, indium oxide-tin oxide system, zinc oxide-indium oxide- A magnesium oxide type etc. are mentioned. A material in which two or more of these metal oxides are combined can also be used.
Moreover, the shape of the said transparent electrode is formed in the shape for position detection of a normal touch panel.

  As a method for forming the transparent electrode, a photolithography method can be suitably used. Specifically, the transparent electrode layer is formed on the surface of the transparent substrate on the side where the decorative layer is formed and inside the decorative region. Next, a resist layer is formed on the transparent electrode layer, and pattern exposure and development are performed to form a resist pattern. Next, the exposed portion of the transparent electrode layer is etched to remove the resist pattern. Thereby, a transparent electrode can be formed in a predetermined pattern.

As a method for forming the transparent electrode layer, a general method can be used, and examples thereof include a method using a dry process such as a vacuum deposition method, a sputtering method, a CVD method, and an ion plating method.
Moreover, as an etching liquid used for the etching of a transparent electrode layer, it sets suitably according to the metal oxide which comprises a transparent electrode layer. Specifically, when the transparent electrode layer is made of ITO, a mixed aqueous solution of ferric oxide and hydrochloric acid, hydrochloric acid, oxalic acid, hydrobromic acid, or the like can be used.
The resist can be the same as that used in a general photolithography method. Examples of the resist developer and the resist stripper include an aqueous potassium hydroxide solution.

(B) Wiring The wiring in the present invention is formed in a pattern on the decorative layer and contains an inorganic conductive material. The wiring is not particularly limited as long as it has desired conductivity. For example, the wiring may be transparent or opaque.

When the wiring is opaque, examples of the inorganic conductive material include silver, gold, chromium, platinum, aluminum alone, a metal alloy mainly composed of any of these, or a metal composite. it can. As the metal alloy, APC, that is, a silver / palladium alloy is generally used. Examples of the metal complex include MAM (Mo—Al—Mo, that is, a three-layer structure of molybdenum, aluminum, and molybdenum).
Moreover, since the said wiring is the same as the material of the transparent electrode mentioned above, description here is abbreviate | omitted.

  As a method for forming the wiring, a photolithography method can be preferably used. When the wiring is opaque, a printing method such as an ink jet method can be used by using an ink containing a conductive paste, a wire having a metal name, or the like.

6). Manufacturing method As a manufacturing method of the front protective plate for a display device of the present invention, a method of forming an antireflection layer on one surface of the transparent substrate, and then forming a decorative layer on the other surface of the transparent substrate; And a method of forming a decorative layer on one surface of the transparent substrate and then forming an antireflection layer on the other surface of the transparent substrate. In the front protective plate for a display device of the present invention, a method of forming an antireflection layer on one surface of the transparent substrate and then forming a decorative layer on the other surface of the transparent substrate is preferable.
After forming a layer on one surface of the transparent substrate, the front plate for a display device of the present invention is formed by transporting with a roller and forming a layer on the other surface. This is because it can be manufactured with high accuracy.

Hereinafter, a method for producing a front protective plate for a display device of the present invention will be described with reference to the drawings.
5A to 5C are process diagrams illustrating an example of a method for manufacturing a front protective plate for a display device according to the present invention. First, as shown in FIG. 5A, the high refractive index layer 12 is formed by applying a curable resin composition for a high refractive index layer to one surface of the transparent substrate 5 and curing it by ultraviolet irradiation. Subsequently, as shown in FIG. 5B, the low refractive index layer curable resin composition is applied on the high refractive index layer 12 and cured by ultraviolet irradiation to form the low refractive index layer 13. Thereby, the antireflection layer 4 in which the high refractive index layer 12 and the low refractive index layer 13 are laminated is formed on one surface of the transparent substrate 5. Both the high refractive index layer 12 and the low refractive index layer 13 are organic layers.
Next, the transparent substrate 5 is turned upside down, and a decorative layer 6 containing an organic material is formed in a pattern on the other surface of the transparent substrate 5 by photolithography as shown in FIG. 5C. To do.

6A to 6D are process diagrams showing another example of the method for manufacturing the front protective plate for a display device of the present invention. First, as shown in FIG. 6A, the high refractive index layer curable resin composition is directly applied to one surface of the transparent substrate 5 and cured by ultraviolet irradiation to form the high refractive index layer 12. . Subsequently, as shown in FIG. 6B, the low refractive index layer curable resin composition is applied onto the high refractive index layer 12, and cured by ultraviolet irradiation to form the low refractive index layer 13. Thereby, the antireflection layer 4 in which the high refractive index layer 12 and the low refractive index layer 13 are laminated is formed on one surface of the transparent substrate 5.
Next, the transparent substrate 5 is turned upside down, and a decorative layer 6 containing an organic material is formed in a pattern on the other surface of the transparent substrate 5 by photolithography as shown in FIG. 6C. To do. Subsequently, as shown in FIG. 6D, the infrared transmission layer 7 is formed in a pattern on the decorative layer 6 having the opening of the infrared transmission window 3 by a photolithography method.

B. Display device A display device according to the present invention includes the above-described front protective plate for a display device, and a display element having an infrared sensor unit disposed at a position facing an infrared transmission window formed on the front protective plate for the display device. , Characterized by having. In the present invention, when the front protective plate for a display device is used together with an infrared sensor, it is excellent in antireflection and even when an antireflection layer is used, it is possible to prevent a decrease in sensitivity of the infrared sensor. It is.

Hereinafter, the display device will be described with reference to the drawings.
FIG. 7 is a schematic sectional view showing an example of the display device of the present invention. As shown in FIG. 7, for example, the display device 14 is formed of a display device front protective plate 1 and a display element 11. On the display element 11, the infrared sensor unit 10 is disposed at a position facing the infrared transmission window 3. This is because a decrease in sensitivity of the infrared sensor can be prevented. Since the front protective plate 1 for a display device is the same as that shown in FIG. 4 described above, description of other symbols is omitted here.
Hereinafter, each structure in the display apparatus of this invention is demonstrated.

1. Front protective plate for display device The front protective plate for display device according to the present invention is the same as the content described in the item “A. Front protective plate for display device”, and thus the description thereof is omitted here.

2. Display element The display element in this invention will not be specifically limited if it has an infrared sensor part in the position facing the infrared permeation | transmission window formed in the said front protective plate for display apparatuses. This is because the infrared sensor unit is disposed at a position facing the infrared transmission window, thereby preventing a decrease in sensitivity of the infrared sensor.
(1) Display element Specific examples of the display element include a liquid crystal display element, a plasma display element, an EL display element, and an electronic paper element.
Furthermore, as the liquid crystal display element, a TN type (Twisted Nematic type), an STN type (Super Twisted Nematic type), a TSTN type (Triple STN type), an MVA type (Multi-domain Vertical Alignment type), a VA type tantalum type, a VA type, an VA type Type), IPS type (In-Plane Switching type), OCB type (Optically Compensated Bend type) and the like, and an in-cell touch panel liquid crystal element in which a touch panel function is incorporated in any of these types can also be mentioned.

(2) Infrared sensor part The infrared sensor part in this invention is one structure of the infrared communication part which transmits / receives information normally using infrared rays, and performs infrared reception. The infrared sensor unit is also used as a proximity sensor. For example, in a communication device such as a smartphone, the display unit is turned off when an object is approached, such as when an ear is approaching during a call. In addition to preventing malfunction of the touch panel, it also contributes to power saving.
The infrared sensor unit may be used alone or in combination with other sensors such as an illuminance sensor.

3. Applications Applications of the display device of the present invention include, for example, smartphones, mobile phones, tablet terminals, notebook computers, televisions, digital signage, wearable terminals and the like.

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

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

[Example 1]
1. Formation of Antireflection Layer The following materials were used for the antireflection layer.
Low refractive index layer agent: TU2205 (refractive index: n = 1.35 manufactured by JSR Corporation)
High refractive index layer agent: KZ6661 (refractive index: n = 1.60, manufactured by JSR Corporation)
A tempered glass substrate (Dragonrail Asahi Glass Co., Ltd.) having a thickness of 0.5 mm is used as the transparent substrate, and KZ6661 is formed on the entire surface of one surface as a curable resin composition for a high refractive index layer to a thickness of 0.15 μm. The film was spin-coated as described above, exposed for 30 seconds using a high-pressure mercury lamp with an exposure illuminance of 30 mW in an N ₂ atmosphere, and dried at 230 ° C. for 20 minutes to form a high refractive index layer.
Next, TU2205 is spin-coated as a curable resin composition for the low refractive index layer so as to have a film thickness of 0.09 μm, and a low refractive index layer is formed on the high refractive index layer in the same process as the formation of the high refractive index layer. A refractive index layer was formed.

2. Formation of Infrared Transmission Layer Next, an infrared transmission layer was formed on the outer periphery of the surface of the tempered glass substrate opposite to the surface on which the antireflection layer was formed (hereinafter referred to as the back surface). Specifically, the infrared transmission layer resin composition is applied to the outer peripheral portion of the back surface of the tempered glass substrate by 10 μm with a spin coater, dried at 100 ° C. for 3 minutes, and then heated at 180 ° C. with an ultrahigh pressure mercury lamp. Heat treatment was performed by leaving it in an atmosphere for 30 minutes to form an infrared transmission layer.

(Preparation of curable resin composition A)
The polymerization tank is charged with 63 parts by weight of methyl methacrylate (MMA), 12 parts by weight of acrylic acid (AA), 6 parts by weight of 2-hydroxyethyl methacrylate (HEMA), and 88 parts by weight of diethylene glycol dimethyl ether (DMDG). After stirring and dissolving, 7 parts by weight of 2,2′-azobis (2-methylbutyronitrile) was added and dissolved uniformly. Then, it stirred at 85 degreeC under nitrogen stream for 2 hours, and also was made to react at 100 degreeC for 1 hour. 7 parts by weight of glycidyl methacrylate (GMA), 0.4 parts by weight of triethylamine, and 0.2 parts by weight of hydroquinone were added to the resulting solution, and the mixture was stirred at 100 ° C. for 5 hours to obtain a copolymer resin solution (solid content). 50%).

Next, the following materials were stirred and mixed at room temperature to obtain a curable resin composition A.
<Composition of curable resin composition A>
-Copolymer resin solution (solid content 50%)-16 parts by weight-Dipentaerythritol pentaacrylate (manufactured by SR399 Sartomer Co., Ltd.)-24 parts by weight-Orthocresol novolac epoxy resin (Epicoat 180S70 Oily Shell Epoxy Co., Ltd.) 4) parts by weight 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one ... 4 parts by weight diethylene glycol dimethyl ether ... 52 parts by weight

(Preparation of resin composition for infrared transmission layer)
Next, the components in the following amounts were sufficiently mixed to obtain a resin composition for an infrared transmitting layer.
<Composition of composition for infrared transmission layer>
-The above-mentioned curable resin composition A ... 30 parts by weight-Pigment Red 254 ... 10 parts by weight-Pigment Yellow 139 ... 10 parts by weight-Pigment Blue (PB15: 6) ... 10 parts by weight-Diethylene glycol Dimethyl ether: 40 parts by weight

3. Formation of decoration layer Next, the decoration layer was formed in the outer peripheral part of the back surface of the said tempered glass substrate. An infrared transmission window was formed on the decorative layer.
Specifically, the decorative layer resin composition is applied to the outer peripheral portion of the back surface of the tempered glass substrate on which the antireflection layer is formed by a spin coater, dried at 100 ° C. for 3 minutes, and then ultrahigh pressure mercury. After exposing to a predetermined pattern with a lamp, development was performed with a 0.05% by mass aqueous potassium hydroxide solution, and then heat treatment was performed by leaving it in an atmosphere of 180 ° C. for 30 minutes to form a decorative layer.

(Preparation of resin composition for decorative layer)
First, the following components were mixed and sufficiently dispersed in a sand mill to prepare a black pigment dispersion.
<Composition of black pigment dispersion>
Black pigment (Mitsubishi Carbon Black # 2600 manufactured by Mitsubishi Chemical Corporation) ... 20 parts by weight Polymer dispersion material (Disperbyk (registered trademark) 111 manufactured by Big Chemie Japan Co., Ltd.) ... 16 parts by weight Solvent (diethylene glycol dimethyl ether) ... 64 parts by weight

Next, the following amount of components was sufficiently mixed to obtain a resin composition for a decorative layer.
<Composition of resin composition for decoration>
-Black pigment dispersion-50 parts by weight-Curable resin composition A-20 parts by weight-Diethylene glycol dimethyl ether-30 parts by weight

  By performing the above steps, a front protective plate for a display device was obtained.

[Comparative Example 1]
1. Formation of Antireflection Layer The following materials were used for the antireflection layer.
Low refractive index thin film material: Niobium dioxide (refractive index at 550 nm: n = 1.46)
High refractive index thin film material: Niobium pentoxide (refractive index at 550 nm: n = 2.30)
The same tempered glass substrate as in Example 1 was used as the transparent substrate.
Four layers of inorganic layers made of the above materials were laminated on one surface of the tempered glass substrate by a vacuum deposition method to form an antireflection layer.
Specifically, a high refractive index thin film made of niobium pentoxide is formed on the entire surface of one surface of the tempered glass substrate so as to have a thickness of 20 nm, and the low refractive index made of niobium dioxide is formed on the high refractive index thin film. A thin film having a thickness of 15 nm was formed. Further, a high refractive index thin film is formed on the low refractive index thin film to a thickness of 85 nm, a low refractive index thin film is formed on the high refractive index thin film to a thickness of 85 nm, and an antireflection layer is formed. Formed.

2. Formation of Infrared Transmission Layer Since the method for forming the infrared transmission layer is the same as that in Example 1, description thereof is omitted here.

3. Formation of a decoration layer About the formation method of a decoration layer, since it is the same as that of Example 1, description here is abbreviate | omitted.

[Evaluation]
The following evaluation was performed about the front protective plate for display devices of Example 1 and Comparative Example 1 obtained by the method described above.

1. Reflectivity With respect to the obtained front protective plate for a display device, a black tape was applied to the surface opposite to the surface on which the antireflection layer was formed, and the reflectance was measured under the following conditions.
The reflectance in the present invention is measured according to “5.3 Measuring method of reflecting object” in “Measurement method of color—reflection and transmission object color” of JIS Z 8722: 2009. It is the reflectance measured by the condition c of “5.3.1 Geometric conditions of illumination and light reception”.
Under this condition c, the sample is irradiated evenly from all directions, and the reflected light having a direction of 10 ° or less with the direction of the sample surface is received. In this case, the received light beam bundle should not contain light rays having an inclination of 5 ° or more with respect to the center line.

(conditions)
Measuring device: spectrocolorimeter CM-2500d (manufactured by Konica Minolta Co., Ltd.)
・ Illumination / light reception method: d / 8 (diffuse illumination / 8 ° light reception method) (based on DIN (5033 Teil 7) and ISO (7724/1))
・ Light source: D65
・ Measurement method: SCI method (special component include method) (method for measuring the total of regular reflection light and diffuse reflection light)
-1st irradiation area: Measurement diameter = circular with a diameter of 11 mm-Second irradiation area: the same measurement diameter as the first irradiation area-Measurement area: 8 mm circle in the irradiation area (the center of gravity is the same as the irradiation area)
The results are shown in Table 1 and FIG. Table 1 shows the reflectance at 550 nm, which is the wavelength of light that is most visually recognized by humans.

2. Infrared light transmittance An ultraviolet-visible near-infrared spectrophotometer Lambda19 (manufactured by Perkin Elmer) was used to measure the infrared light transmittance in the wavelength region of 800 to 1300 nm, and infrared in all wavelengths in the above wavelength region. The average light transmittance was obtained and evaluated as infrared region characteristics.
In addition, about the front plate for display devices obtained in Example 1 and Comparative Example 1, it was confirmed that the reflectance at a wavelength of 550 nm was less than 0.5%, and the transmittance of infrared light was measured.
The results are shown in Table 1 and FIG.

From the results of Example 1 and Comparative Example 1, the visible region characteristics (low reflection characteristics in the visible light region) of the front protective plate for a display device were better in Comparative Example 1 than in Example 1. That is, it was found that the antireflection layer formed of an inorganic material has a lower reflectance than that formed of an organic material, and the low reflection characteristic is superior when formed of an inorganic material.
However, Example 1 was better than Comparative Example 1 in terms of infrared region characteristics (average of infrared light transmittance at all wavelengths in the wavelength region 800-1300 nm). In other words, the antireflection layer formed of an organic material shows higher infrared light transmittance than that formed of an inorganic material, and the infrared light transmittance is higher when formed of an organic material. I found it excellent.
Therefore, it was found that it is better to form an antireflection film with an organic material in order to suppress the reflection of visible light and improve the transmittance of infrared light.
Further, from the values of a ^* and b ^* shown in Table 1, it can be seen that the color tone is suppressed when the organic material is formed compared to the inorganic material.
Therefore, it is preferable to form the antireflection layer with an organic material from the viewpoints of low reflection characteristics with respect to visible light, infrared light transmittance, and tint suppression.

DESCRIPTION OF SYMBOLS 1 ... Front protective plate for display apparatuses 2 ... Decoration area 3 ... Infrared transmission window 4 ... Antireflection layer 5 ... Transparent substrate 6 ... Decoration layer 7 ... Infrared transmission layer 8 ... Transparent electrode 9 ... Wiring 10 ... Infrared sensor Part 11: Display element 12: High refractive index layer 13: Low refractive index layer 14: Display device

Claims (4)

A front protective plate for a display device, comprising: a transparent substrate; a decorative layer formed on an outer peripheral portion of one surface of the transparent substrate; and an antireflection layer formed on the entire surface of the other surface of the transparent substrate. There,
The decorative region, which is a region where the decorative layer is formed, is provided with an infrared transmission window that transmits infrared light,
The front protective plate for a display device, wherein the antireflection layer is formed of an organic material or an organic material and fine particles having an average particle diameter of 50 nm or less.   2. The front protection for a display device according to claim 1, wherein an infrared transmission layer that shields visible light and transmits infrared light is formed in a region where the infrared transmission window is formed. Board.   The transparent electrode for position detection of a touch panel is formed in the surface of the side in which the said decoration layer of the said transparent substrate is formed, and the inside of the said decoration area | region. Item 3. A front protective plate for a display device according to Item 2.   It arrange | positioned in the position which opposes the said infrared transmission window formed in the front-surface protective plate for display apparatuses as described in any one of Claim 1- Claim 3, and the said front-surface protective board for display apparatuses. And a display device having an infrared sensor portion.