Glass plate structure and in-vehicle display device

Abstract

The present invention pertains to a glass plate structure. This glass plate structure comprises a glass plate provided with a first main surface and a second main surface, an antireflection film disposed on the first main surface and a print part disposed on the second main surface, wherein: the first main surface, which is an end area of the glass plate, is curved convexly and has a curved surface area, said curved surface area having a curvature radius r corresponding to 50% or more of the plate thickness t of the glass plate, and a flat surface area connected to the curved surface area; the antireflection film is a laminate comprising high refractive index layers and low refractive index layers alternately laminated; the antireflection film consists of not more than 12 layers; in the flat surface area, the total film thickness of the antireflection film is 400 nm or less; and, in the flat surface area, the film thickness of the outermost layer of the antireflection film is 90 nm or more.

Description

[Technical field]

[0001] The present invention relates to a glass plate structure and an in-vehicle display device. [Background technology]

[0002] Conventionally, a glass plate structure having a glass plate, an anti-reflection film arranged on a first main surface of the glass plate, and a printed portion (frame portion) arranged on a second main surface of the glass plate has been used as a cover glass in display devices such as in-vehicle display devices (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-197176 [Patent Document 2] International Publication No. 2018 / 110499 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a glass plate structure in which the edge of the first main surface is curved in a convex shape. The inventors have discovered that when such a glass plate structure is viewed from the first main surface side, a phenomenon in which the edges appear red (hereinafter also referred to as "edge red discoloration") may occur. When such a glass plate structure is used as a cover glass for a display device with its edges exposed, a user of the display device visually recognizes red discoloration at the edges. Since red is a so-called warning color, the red edge discoloration may not be liked by users of the display device, and may also be mistaken for an abnormality or failure of the display device by users of the display device.

[0005] Test Example 2 of Patent Document 2 discloses a 19-layer antireflection film (total film thickness: 621.3 nm). The inventors of the present invention have found that the use of such an antireflection film has a certain degree of effect in suppressing edge red discoloration. However, the number of layers of the antireflection film is excessively large, making the manufacturing process very complicated.

[0006] Therefore, an object of the present invention is to provide a glass plate structure which has a small number of anti-reflection film layers and in which red discoloration at edges is suppressed. [Means for solving the problem]

[0007] As a result of intensive research, the present inventors have found that the above object can be achieved by adopting the following configuration. That is, the present invention provides the following [1] to [7]. [1] A glass plate structure comprising: a glass plate having a first principal surface and a second principal surface; an antireflection film disposed on the first principal surface; and a printed portion disposed on the second principal surface, wherein the first principal surface is an edge region of the glass plate, the first principal surface having a curved surface region that is convexly curved and has a radius of curvature r that is 50% or more of a thickness t of the glass plate, and a flat surface region connected to the curved surface region, the antireflection film being a laminate in which high refractive index layers and low refractive index layers are alternately repeated, the number of layers of the antireflection film is 12 or less, the total film thickness of the antireflection film in the flat surface region is 400 nm or less, and the film thickness of an outermost layer of the antireflection film in the flat surface region is 90 nm or more. [2] The glass plate structure according to the above [1], wherein the glass plate has been subjected to a chemical strengthening treatment. [3] The glass plate structure according to the above [1] or [2], further comprising an antiglare layer provided on the first main surface. [4] The glass plate structure according to any one of the above [1] to [3], wherein the outermost layer of the antireflection film is the low refractive index layer containing silicon oxide. [5] The glass plate structure according to any one of the above [1] to [4], wherein the antireflection film has 9 or less layers. [6] The glass plate structure according to any one of the above [1] to [5], wherein the antireflection film has four or more layers. [7] An in-vehicle display device comprising: a display panel; and the glass plate structure according to any one of [1] to [6] above, which covers the display panel. Effect of the Invention

[0008] According to the present invention, it is possible to provide a glass plate structure which has a small number of anti-reflection film layers and in which red discoloration at edges is suppressed. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing a glass plate structure. [Diagram 2] FIG. 2 is a schematic diagram showing how to determine the radius of curvature of a curved surface region. [Diagram 3] FIG. 3 is a cross-sectional view showing the in-vehicle display device. [Figure 4] FIG. 4 is a schematic diagram showing the positional relationship between the light source and the detector. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiment. Various modifications and substitutions can be made to the following embodiment without departing from the scope of the present invention.

[0011] How to determine the thickness t of the glass plate, the radius of curvature r of the curved surface area, and the film thickness of the anti-reflection film will be described later.

[0012] [Glass plate structure] 1 is a cross-sectional view showing a glass plate structure 1. The glass plate structure 1 has a glass plate 2, an anti-reflection film 3, and a printed portion 4.

[0013] The glass plate 2 has a central portion 2a including the center of the glass plate 2, and an end portion 2b connected to the central portion 2a. The glass plate 2 has a first main surface 21 which is one of its main surfaces, and a second main surface 22 which is the other of its main surfaces.

[0014] The first main surface 21 has a flat surface region 21a which is a region of the central portion 2a of the glass plate 2. The flat surface region 21a is a region of a flat surface in a cross section perpendicular to the first main surface 21. It can also be said that the portion of the glass plate 2 where the flat surface region 21a is located is the central portion 2a.

[0015] The first main surface 21 further has a curved surface region 21b which is a region of the end portion 2b of the glass plate 2. The curved surface region 21b and the flat surface region 21a are connected to each other. The curved surface region 21b is convexly curved (bent like a bow) in a cross section perpendicular to the first main surface 21. Chamfering may be performed on an end portion extending from the curved surface region 21b of the first main surface 21 to the second main surface 22. Hereinafter, this end portion will also be referred to as an "end chamfered portion" for convenience.

[0016] In a cross section perpendicular to the first main surface 21, a distance L (the distance from the outermost end 2c of the glass plate 2 to the central portion 2a) defining the end 2b of the glass plate 2 is a distance in a direction parallel to the surface direction of the flat surface region 21a of the first main surface 21. The distance L is, for example, 0.5 mm or more and 5 mm or less, and preferably 1 mm or more and 4 mm or less. Such a distance L is obtained by measuring at a magnification of 100 to 200 times using a contour measuring device (for example, a contour record manufactured by Tokyo Seimitsu Co., Ltd.).

[0017] The second main surface 22 is a flat surface that faces a display panel 103 (see FIG. 3) described later.

[0018] The thickness t of the glass sheet 2 is the thickness t of the glass sheet 2 at the central portion 2a. The thickness t of the glass plate 2 is, for example, 0.5 mm or more, and preferably 0.7 mm or more, from the viewpoint of durability, etc. On the other hand, the thickness t of the glass plate 2 is preferably 3.0 mm or less, more preferably 2.5 mm or less, and even more preferably 2.0 mm or less. The plate thickness t of the glass plate 2 is obtained by measuring at a magnification of 100 to 200 times using a contour measuring device (for example, Contour Record manufactured by Tokyo Seimitsu Co., Ltd.).

[0019] The radius of curvature r (see FIG. 2) of the curved surface region 21b is 50% or more, and preferably 60% or more, of the thickness t of the glass plate 2. On the other hand, the radius of curvature r of the curved surface region 21b is preferably 200% or less, and more preferably 150% or less.

[0020] The radius of curvature r of the curved surface region 21b is obtained by measuring at a magnification of 100 to 200 times using a contour measuring device (for example, Contour Record manufactured by Tokyo Seimitsu Co., Ltd.). Fig. 2 is a schematic diagram showing how to find the radius of curvature r of the curved surface region 21b. As shown in Fig. 2, a tangent line 52 is drawn to an arbitrary point 51 of the curved surface region 21b, and the radius of an arc 53 passing through the tangent line 52 is the radius of curvature r. The radius of curvature r is found in the same manner over the entire curved surface region 21b. The radius of curvature r over the entire curved surface region 21b satisfies the above range.

[0021] Let us return to the explanation of Figure 1. The size etc. of the glass plate 2 in a plan view (viewed from the first main surface 21 side) is not particularly limited, and is determined appropriately depending on, for example, the size etc. of the display panel 103 described later.

[0022] The printed portion 4 is disposed on the second main surface 22. The printed portion 4 is disposed on the edge portion 2b of the glass plate 2. The printed portion 4 may be disposed continuously from the edge portion 2b of the glass plate 2 in a part of the central portion 2a of the glass plate 2. The printed portion 4 may cover a part or the whole of the above-mentioned edge chamfer portion.

[0023] The antireflection film 3 is a laminate in which low refractive index layers and high refractive index layers are alternately repeated. The number of layers in the antireflection film 3 is 12 or less. The outermost layer 31 of the antireflection film 3 is a low refractive index layer or a high refractive index layer. The anti-reflection coating 3 is disposed on the first main surface 21. More specifically, the anti-reflection coating 3 is disposed continuously on the flat surface region 21a and the curved surface region 21b of the first main surface 21.

[0024] When such a glass plate structure 1 is viewed from the first main surface 21 side, red discoloration at the edge may be visually recognized. Specifically, for example, if an area in which the x value of the Yxy color system is 0.33 or more continues for 0.1 mm or more in the curved surface area 21b where the anti-reflection film 3 is disposed, it can be said that red discoloration of the edge has occurred (see [Example]).

[0025] However, in this embodiment, the total film thickness td in the flat surface region 21a of the antireflection coating 3 is 400 nm or less, and the film thickness ta in the flat surface region 21a of the outermost layer 31 of the antireflection coating 3 is 90 nm or more. This prevents edge red discoloration even when the antireflection coating 3 has a small number of layers, 12 or less. It is presumed that this is because the anti-reflection film 3 can reduce the reflectance of light containing red wavelengths.

[0026] Each part of the glass plate structure 1 will be described in more detail below.

[0027] <Glass plate> The glass type of the glass plate 2 may be, for example, soda lime glass or aluminosilicate glass (SiO 2 -Al 2 O 3 -Na 2 O-based glass, etc. When carrying out the chemical strengthening treatment described later, chemically strengthened glass based on aluminosilicate glass (for example, "Dragontrail (registered trademark)") is also suitably used.

[0028] "grinding" As described above, the end portion 2b of the glass plate 2 is provided with a curved surface region 21b in which the first main surface 21 is curved. The curved surface region 21b is formed by grinding a raw plate that will become the glass plate 2, for example, with a rotary grindstone. The conditions for grinding using a rotating grindstone (grit size, processing speed, grinding amount, etc.) are appropriately selected according to the desired radius of curvature r of the curved surface region 21b, etc. In this case, rough processing may be performed using a grindstone with a coarse grain size first, and then finish processing may be performed using a grindstone with a fine grain size, within a range that does not excessively increase the number of steps and complicate the work.

[0029] <Anti-glare treatment> An antiglare layer 5 is preferably provided on the first main surface 21 of the glass plate 2 . The antiglare layer 5 is a layer including a first main surface 21. When the antiglare layer 5 is provided on the glass plate 2, the first main surface 21 has an uneven structure. The antiglare layer 5 is formed by carrying out an antiglare treatment on a raw plate that will become the glass plate 2. The method of anti-glare treatment is not particularly limited, and examples thereof include a method of etching the surface layer of the raw plate that will become the glass plate 2; a method of applying a coating liquid containing fine particles and a matrix to the surface of the raw plate that will become the glass plate 2 and hardening the matrix; and the like.

[0030] The antiglare layer 5 may be, for example, a layer corresponding to the “underlayer” described in paragraphs

[0023] to

[0036] of International Publication No. 2017 / 038868 (hereinafter, for convenience, also referred to as “Reference 1”). In this case, the antiglare layer 5 is formed by applying a predetermined coating composition to a base plate that will become the glass plate 2 to form a coating film, and then baking the coating film. More specifically, the antiglare layer 5 is formed by the method described in paragraphs

[0047] to

[0124] of Reference 1.

[0031] Chemical strengthening treatment The glass plate 2 is preferably subjected to a chemical strengthening treatment. When chemical strengthening treatment is performed, a glass for chemical strengthening is used as the glass type. The typical method of chemical strengthening is to treat glass with KNO 3 One method is to immerse the material in molten salt, perform ion exchange treatment, and then cool it to room temperature. 3The treatment conditions, such as the temperature of the molten salt and the immersion time, may be set so that the surface compressive stress (CS) and the thickness of the compressive stress layer (DOL) of the compressive stress layer are desired values. The surface compressive stress (CS) of the compressive stress layer is preferably 500 MPa or more, more preferably 600 MPa or more, and even more preferably 700 MPa or more, while the surface compressive stress (CS) of the compressive stress layer is preferably 1300 MPa or less. The thickness (DOL) of the compression stress layer is preferably 10 μm or more, more preferably 15 μm or more, further preferably 20 μm or more, and particularly preferably 25 μm or more.

[0032] <Anti-reflection film> An anti-reflection film 3 is provided on the first main surface 21 of the glass plate 2. This suppresses light reflection, enabling the display image of the display panel 103, which will be described later, to be clear. The antireflection film 3 is a laminate in which high refractive index layers and low refractive index layers are alternately repeated. The number of layers in the antireflection film 3 is 12 or less, preferably 9 or less, more preferably 4 or more, and further preferably 4, 6 or 8 layers. The high refractive index layer is a layer having a refractive index of 1.9 or more at a wavelength of 550 nm, and the low refractive index layer is a layer having a refractive index of 1.6 or less at a wavelength of 550 nm. The materials for the high refractive index layer and the low refractive index layer are not particularly limited and can be selected in consideration of the required degree of antireflection, productivity, and the like. Suitable examples of materials constituting the high refractive index layer include materials containing at least one selected from the group consisting of niobium, titanium, zirconium, tantalum, and silicon. 2 O 5 ), titanium dioxide (TiO 2 ), zirconium oxide (ZrO 2 ), tantalum oxide (Ta 2 O 5 ), silicon nitride, etc. Examples of materials constituting the low refractive index layer include materials containing silicon. Specifically, silicon oxide (SiO 2), a material containing a mixed oxide of Si and Sn, a material containing a mixed oxide of Si and Zr, a material containing a mixed oxide of Si and Al, and the like.

[0033] The outermost layer 31 of the antireflection coating 3 is preferably a low refractive index layer, and more preferably a low refractive index layer containing silicon oxide.

[0034] As described above, the total thickness td of the antireflection coating 3 in the flat surface region 21a is 400 nm or less, and the thickness ta of the outermost layer 31 of the antireflection coating 3 in the flat surface region 21a is 90 nm or more. This suppresses edge red discoloration.

[0035] As described later, the total thickness td of the antireflection coating 3 in the flat surface region 21a is preferably 380 nm or less, more preferably 340 nm or less, because edge red discoloration can be further suppressed. On the other hand, the total thickness td is preferably 200 nm or more, more preferably 220 nm or more.

[0036] Similarly, the film thickness ta of the flat surface region 21a of the outermost layer 31 of the antireflection coating 3 is preferably 95 nm or more, and more preferably 100 nm or more, in order to further suppress edge reddening. On the other hand, from the viewpoint of improving the antireflection properties of the antireflection coating 3, the film thickness ta is preferably 135 nm or less, more preferably 130 nm or less, and even more preferably 125 nm or less.

[0037] More specifically, for example, when the antireflection coating 3 has four or five layers, the total thickness td of the antireflection coating 3 in the flat surface region 21a is preferably 285 nm or less, more preferably 265 nm or less. On the other hand, the total thickness td is preferably 245 nm or more, more preferably 250 nm or more. In this case, the thickness ta of the outermost layer 31 of the antireflection coating 3 in the flat surface region 21a is preferably 95 nm or more, and more preferably 100 nm or more, while the thickness ta is preferably 130 nm or less, more preferably 110 nm or less, and further preferably 102.5 nm or less. If the thickness of the antireflection film 3 falls within this range, the color of the edge portion 2b of the glass plate 2 can be kept within an appropriate range, and the color and reflectance of the central portion 2a of the glass plate 2 can also be kept within an appropriate range.

[0038] For the same reason, when the number of layers of the antireflection coating 3 is 6 or 7, the total thickness td of the antireflection coating 3 in the flat surface region 21a is preferably 290 nm or less, more preferably 285 nm or less. On the other hand, the total thickness td is preferably 250 nm or more, more preferably 255 nm or more. In this case, the thickness ta of the outermost layer 31 of the antireflection coating 3 in the flat surface region 21a is preferably 95 nm or more, and more preferably 100 nm or more, while the thickness ta is preferably 130 nm or less, and more preferably 120 nm or less.

[0039] For the same reason, when the number of layers in the antireflection coating 3 is 8 or 9, the total thickness td of the antireflection coating 3 in the flat surface region 21a is preferably 350 nm or less, and more preferably 340 nm or less. On the other hand, the total thickness td is preferably 280 nm or more, and more preferably 300 nm or more. In this case, the thickness ta of the outermost layer 31 of the antireflection coating 3 in the flat surface region 21a is preferably 95 nm or more, and more preferably 100 nm or more, while the thickness ta is preferably 140 nm or less, and more preferably 130 nm or less.

[0040] The thickness of each layer of the anti-reflection film 3 except for the outermost layer 31 is appropriately adjusted taking into consideration the color tone other than red, the reflectance, and the like.

[0041] The method for forming the anti-reflective coating 3 is not particularly limited, and examples thereof include film formation methods such as sputtering, such as pulse sputtering, AC sputtering, and digital sputtering; CVD (chemical vapor deposition); ALD (atomic layer deposition); and evaporation. For example, when forming a film by pulse sputtering, the glass plate 2 is placed in a chamber containing a mixed gas atmosphere of inert gas and oxygen gas, and a target is selected to have a desired composition, and a film is formed.

[0042] Incidentally, when the anti-reflection film 3 is formed by sputtering, for example, each layer of the anti-reflection film 3 is more difficult to deposit on the convexly curved curved surface region 21b than on the flat surface region 21a. Therefore, the thickness of each layer in the curved surface region 21b is thinner than the thickness of each layer in the flat surface region 21a. As a result, for the outermost layer 31 of the anti-reflection coating 3, the ratio (tb / ta) of the film thickness tb in the curved surface region 21b to the film thickness ta in the flat surface region 21a is 100% or less. For example, the ratio (tb / ta) is 95% or less, and preferably 85% or less. On the other hand, the ratio (tb / ta) is preferably 60% or more, and more preferably 70% or more.

[0043] For the antireflection coating 3, the ratio of the film thickness in the curved surface region 21b to the film thickness in the flat surface region 21a for the layers other than the outermost layer 31 is assumed to satisfy the ratio (tb / ta) of the outermost layer 31.

[0044] The thickness of each layer of the anti-reflection film is measured at a magnification of 50,000 times using a scanning electron microscope (SEM), such as "SU-70" manufactured by Hitachi High-Technologies Corporation. However, since the thickness of each layer in the curved surface region 21b of the anti-reflection coating 3 is thicker closer to the center 2a of the glass plate 2 and thinner closer to the extreme edge 2c of the glass plate 2, the thickness is taken as the thickness at the midpoint of the above-mentioned distance L.

[0045] <Printing Department> The printed portion 4 is formed, for example, in a frame shape at the end portion 2b of the glass plate 2. As a result, the printed portion 4 conceals wiring (not shown) connected to the display panel 103 (described later) so that it cannot be seen from the first main surface 21 side of the glass plate 2.

[0046] The printed portion 4 is formed by printing colored ink on the glass plate 2. Methods for printing colored ink onto the glass plate 2 include, for example, bar coating, reverse coating, gravure coating, die coating, roll coating, screen printing, photolithography, offset printing using a film, pad, roll, etc., inkjet printing, spray printing, etc., of which the screen method is preferred because it is easy to print.

[0047] The color of the color ink is often black or white, but is not limited to this. The color ink is not limited to decorative purposes, and may have additional functions such as transmitting a specific wavelength. The color ink is not particularly limited, and examples that can be used include inorganic inks containing ceramics (fired ceramics) and the like; organic inks containing a coloring material such as a dye or pigment and an organic resin; and the like. Examples of ceramics contained in inorganic inks include oxides such as chromium oxide and iron oxide; carbides such as chromium carbide and tungsten carbide; carbon black; and mica. The colorant (dye or pigment) contained in the organic ink is not particularly limited and can be used. Examples of organic resins contained in organic inks include homopolymers such as epoxy resins, acrylic resins, polyethylene terephthalate, polyethersulfone, polyarylate, polycarbonate, phenolic resins, acrylonitrile-butadiene-styrene resins, polyurethane, polymethyl methacrylate, polyvinyl, polyvinyl butyral, polyether ether ketone, polyethylene, polyester, polypropylene, polyamide, and polyimide; copolymers of monomers of these resins and monomers copolymerizable therewith; and the like. Between inorganic inks and organic inks, organic inks are preferred because they have a lower baking temperature, and from the standpoint of chemical resistance, organic inks containing pigments are more preferred.

[0048] [In-vehicle display device] Next, with reference to FIG. 3, an in-vehicle display device 101 that is mounted on a vehicle and used as a display device using the glass plate structure 1 will be described. 3 is a cross-sectional view showing the in-vehicle display device 101. The in-vehicle display device 101 is, for example, a car navigation device or a rear seat entertainment (RSE) device that enables passengers in the rear seats to view images and the like.

[0049] The in-vehicle display device 101 has a housing 102 that houses each component. A display panel 103 is disposed inside the housing 102. The display panel 103 is, for example, a liquid crystal panel, an organic EL (electroluminescence) panel, or an electronic ink type panel, and may have a touch panel or the like. The glass plate structure 1 is attached to the display panel 103 by the adhesive layer 104. In this manner, the glass plate structure 1 functions as a cover glass for the display panel 103. The adhesive layer 104 may be, for example, a layer made of a transparent resin obtained by curing a liquid curable resin composition. The adhesive layer 104 may be an OCA (Optical Clear Adhesive) film or tape. The thickness of the adhesive layer 104 is preferably 5 μm or more, and more preferably 50 μm or more. On the other hand, the thickness of the adhesive layer 104 is preferably 400 μm or less, and more preferably 200 μm or less. EXAMPLES

[0050] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples. Examples 1, 3, and 5 are examples, and Examples 2, 4, 6, and 7 are comparative examples.

[0051] [Example 1] A glass plate structure 1 of Example 1 was produced as follows.

[0052] <Preparing the glass plate> First, a chemically strengthened glass ("Dragon Trail" manufactured by AGC) was prepared as a raw plate for the glass plate 2. The prepared raw plate was subjected to grinding, antiglare treatment, and chemical strengthening treatment, which will be described below, in this order, to obtain a rectangular glass plate 2 (plate thickness t: 1.3 mm, size: 250 mm × 145 mm) having an antiglare layer 5.

[0053] "grinding" The prepared raw plate was ground using a rotary grindstone, so that the glass plate 2 obtained had a distance L of the end portion 2b of 2 mm, and a maximum curvature radius r of the curved surface region 21b of 5 mm and a minimum curvature radius r of 0.7 mm.

[0054] <Anti-glare treatment> An antiglare layer 5 was formed by preparing a coating liquid, coating the coating liquid, and baking the coating liquid in the same manner as in Example 3 of Reference Document 1 (WO 2017 / 038868). More specifically, first, the coating solution (C) described in paragraphs

[0165] to

[0167] of Reference 1 was prepared. Next, the temperature in the coating booth of the electrostatic coating device was adjusted to within the range of 25°C ± 1°C, and the humidity was adjusted to within the range of 50% ± 10%. The ground raw plate was heated to 30°C ± 3°C in advance and placed on a chain conveyor of an electrostatic coating device via a conductive substrate. While being transported at a constant speed by the chain conveyor, a coating liquid (C) having a temperature within a range of 25°C ± 1°C was applied by electrostatic coating to the surface that would become the first main surface 21 of the glass plate 2. The conditions of the electrostatic coating were the coating conditions (amount of coating liquid, cup rotation speed, nozzle height, cup diameter, voltage, number of applications) of Example 3 described in Table 1 of Reference Document 1. The plate was then baked in air at 450°C for 30 minutes.

[0055] Chemical strengthening treatment The glass plate was subjected to chemical strengthening treatment after grinding and anti-glare treatment. The entire glass plate was immersed in KNO 3 This was done by immersing the sample in a molten salt.

[0056] Formation of Anti-Reflection Film An antireflection coating 3 having six layers, each having a high refractive index layer (niobium oxide layer) and a low refractive index layer (silicon oxide layer) alternately arranged, was formed on the first main surface 21 of the obtained glass plate 2 according to the following method. The film thickness of each layer in the flat surface region 21a is shown in Table 1 below.

[0057] The glass plate 2 was fixed to a rotating jig in the chamber of a load-lock type sputtering deposition apparatus (RAS) manufactured by Synchron. A Nb thin film was formed using Nb as the sputtering source. Then, oxygen gas was introduced into the radical source to oxidize the Nb thin film. These two operations were repeated while rotating for a time period that corresponded to the film thickness. A 705 mm x 147 mm Nb target was used as the sputtering target. The sputtering conditions were a pressure of 0.2 Pa, a drum rotation speed of 100 rpm, and an output of 5.5 kW. In this way, niobium oxide (Nb 2 O 5 ) was formed as a high refractive index layer (first layer). Next, a film was formed on the first layer using Si as the sputtering source and oxygen gas as the radical source. At this time, a thin Si film was first formed on the first layer, and then it was oxidized with oxygen gas. These two operations were repeated while rotating for a time according to the film thickness. A 705 mm x 147 mm Si target was used as the sputtering target. The sputtering conditions were a pressure of 0.2 Pa, a drum rotation speed of 100 rpm, and an output of 7.5 kW. In this way, a silicon oxide (SiO 2 ) was formed as a low refractive index layer (second layer). Next, niobium oxide (Nb 2 O 5 ) was formed as a high refractive index layer (third layer). Next, silicon oxide (SiO 2 ) was formed as a low refractive index layer (fourth layer). Next, niobium oxide (Nb 2 O 5 ) was formed as a high refractive index layer (fifth layer). Next, silicon oxide (SiO 2 ) was formed as a low refractive index layer (sixth layer). This sixth layer was the outermost layer 31 of the antireflection film 3.

[0058] As described above, each layer of the antireflection film 3 is more difficult to deposit on the convexly curved curved surface region 21b than on the flat surface region 21a. Therefore, the film thickness of each layer on the curved surface region 21b is thinner than that on the flat surface region 21a. The ratio (tb / ta) of the outermost layer 31 is shown in the following Table 1. Note that for the layers other than the outermost layer 31, the ratio of the film thickness in the curved surface region 21b to the film thickness in the flat surface region 21a was similar to the ratio (tb / ta) of the outermost layer 31.

[0059] <Formation of Printing Part> A frame-shaped print portion 4 having a width of 10 mm was formed on the second main surface 22 of the glass plate 2 . More specifically, first, black ink was applied to a thickness of 5 μm using a screen printer, and then dried at 150° C. for 10 minutes to form a first printed layer. Next, black ink was applied to a thickness of 5 μm on the first printed layer in the same manner, and then dried at 150° C. for 40 minutes to form a second printed layer. In this way, a printed part 4 was formed in which the first printed layer and the second printed layer were laminated. HFGV3RX01 (product name, manufactured by Seiko Corporation) was used as the black ink.

[0060] [Example 2] By changing the deposition time of each of the first to sixth layers of the antireflection coating 3, the film thickness of each layer in the flat surface region 21a was changed to a value different from that in Example 1. Otherwise, a glass plate structure 1 was obtained in the same manner as in Example 1. In Example 2, the shape (distance L and radius of curvature r) of the curved surface region 21b is the same as in Example 1. Therefore, the ratio (tb / ta) is the same as in Example 1, and the film thickness tb also changes accordingly (the same applies to the following examples).

[0061] [Example 3 and Example 4] A four-layer antireflection film 3 was formed in which high refractive index layers (niobium oxide layers) and low refractive index layers (silicon oxide layers) were alternately repeated. The film thickness of each layer in the flat surface region 21a is shown in Table 1 below. Other than that, the same procedure as in Example 1 was carried out to obtain a glass plate structure 1.

[0062] [Examples 5 and 6] The anti-reflection film 3 was formed by alternately repeating eight layers of high refractive index layers (niobium oxide layers) and low refractive index layers (silicon oxide layers). The film thickness of each layer in the flat surface region 21a is shown in Table 1 below. Other than that, the same procedure as in Example 1 was carried out to obtain a glass plate structure 1.

[0063] [Example 7] A seven-layer antireflection coating 3 was formed in which high refractive index layers (niobium oxide layers) and low refractive index layers (silicon oxide layers) were alternately repeated. However, the first layer was a low refractive index layer (silicon oxide layer), and the seventh layer, which was the outermost layer 31, was also a low refractive index layer (silicon oxide layer). The film thickness of each layer in the flat surface region 21a is shown in Table 1 below. Other than that, the same procedure as in Example 1 was carried out to obtain a glass plate structure 1.

[0064] [evaluation] The following evaluations were performed on the glass plate structures 1 of Examples 1 to 7. The evaluation results are shown in Table 1 below.

[0065] (Prevention of reddening of edges) For the curved surface region 21b of the glass plate structure 1 on which the antireflection film 3 was disposed, the x value in the Yxy color system was determined. At this time, as shown in FIG. 4, the angle θ of light 203 incident on the glass plate structure 1 from the light source 201 is 1 and the angle θ of the light 204 reflected by the glass plate structure 1 and detected by the detector 202. 2 The angle θ 1 and angle θ 2 was set to 10 to 80 degrees. A light source sensitive to the visible light region was used as the light source 201. Specifically, a white LED light source (OPF-S100X100W-PS, manufactured by Optex FA) was used. Since the intensity of each wavelength in the visible region is not constant for a white LED, a white calibration plate was used to obtain spectrum data and create correction values, and the Yxy values ​​in the Yxy color system were calculated using the correction values. As the detector 202, a spectroradiometer ("SR-5000" manufactured by Topcon Technohouse) was used. If the area where the x value is 0.33 or more did not continue for 0.1 mm or more, it was marked as "A." If the area where the x value is 0.33 or more continued for 0.1 mm or more, it was marked as "B." These are shown in Table 1 below. If it is marked as "A," it can be evaluated that reddening of the edge has been suppressed.

[0066] <Anti-reflection> The antireflection properties of the antireflection film 3 disposed on the curved surface region 21b were evaluated. Specifically, the Y value (SCI) in the Yxy color system was measured for the edge 2b of the glass plate 2 on which the printed portion 4 and the anti-reflection film 3 were formed, using a spectrophotometer (CM-2600D) manufactured by Konica Minolta. When the Y value was 2.0 or less, it was rated as "A," and when the Y value was greater than 2.0, it was rated as "B," as shown in Table 1. When it was rated as "A," it could be evaluated as having excellent antireflection properties.

[0067] [Table 1]

[0068] [Summary of evaluation results] As shown in Table 1 above, in Examples 1, 3 and 5 in which the total film thickness td of the anti-reflection coating 3 in the flat surface region 21a was 400 nm or less and the film thickness ta of the outermost layer 31 of the anti-reflection coating 3 in the flat surface region 21a was 90 nm or more, red discoloration at the edges was suppressed. In contrast, in Examples 2, 4, 6 and 7 in which the film thickness ta in the flat surface region 21a of the outermost layer 31 of the antireflection coating 3 was not 90 nm or more, the suppression of edge redness was insufficient.

[0069] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2020-022169 filed on February 13, 2020, the contents of which are incorporated herein by reference. [Explanation of symbols]

[0070] 1: Glass plate structure 2: Glass plate 2a: Center of glass plate 2b: Edge of glass plate 2c: The very edge of the glass plate 21: First main surface of glass plate 21a: Flat surface region of the first main surface 21b: Curved surface region of the first principal surface 22: Second main surface of glass plate 3: Anti-reflection film 31: The outermost layer of the anti-reflective coating 4: Printing department 51: point 52: Tangent 53: Arc 101: Vehicle-mounted display device 102: Cabinet 103: Display panel 104: Adhesive layer r: radius of curvature of the curved surface area t: thickness of glass plate ta: film thickness of the flat surface area of ​​the outermost layer of the anti-reflection coating tb: The thickness of the outermost layer of the anti-reflection coating in the curved surface area td: Total thickness of the anti-reflection coating on the flat surface area L: End distance

Claims

1. a glass sheet having a first major surface and a second major surface; an anti-reflective coating disposed on the first major surface; A printing portion disposed on the second main surface, The first main surface is A curved surface region at an end of the glass plate, which is convexly curved and has a radius of curvature r of 50% or more of a thickness t of the glass plate; a flat surface region connected to the curved surface region, the antireflection film is a laminate in which high refractive index layers and low refractive index layers are alternately repeated, The number of layers of the antireflection film is 12 or less, The total film thickness of the antireflection film in the flat surface region is 400 nm or less; the thickness of the outermost layer of the antireflection film in the flat surface region is 90 nm or more; the thickness of the outermost layer of the antireflection film in the curved surface region is 80 nm or more; A glass plate structure, wherein the Y value (SCI) of a Yxy color system is 2.0 or less in the curved surface region on which the antireflection film is disposed.

2. A glass plate structure as described in claim 1, wherein the film thickness of the outermost layer of the anti-reflection film in the flat surface region is 90 nm or more and 135 nm or less.

3. A glass plate structure as described in claim 1 or 2, wherein for the outermost layer of the anti-reflection film, the ratio (tb / ta) of the film thickness tb in the curved surface region to the film thickness ta in the flat surface region is 60% or more and 95% or less.

4. A glass plate structure described in any one of claims 1 to 3, wherein in the curved surface region on which the anti-reflection film is disposed, the region in which the x value of the Yxy color system is 0.33 or more is less than 0.1 mm2.

5. A glass plate structure described in any one of claims 1 to 4, wherein the radius of curvature r of the curved surface region is 200% or less of the plate thickness t of the glass plate.

6. A glass plate structure described in any one of claims 1 to 5, wherein the second main surface is a surface facing a display panel and is a flat surface.

7. A glass plate structure described in any one of claims 1 to 6, having an end chamfer portion at an end spanning from the curved surface region to the second main surface.

8. The glass plate structure according to any one of claims 1 to 7, wherein the glass plate has been subjected to a chemical strengthening treatment.

9. The glass plate structure according to any one of claims 1 to 8, further comprising an antiglare layer provided on the first main surface.

10. The glass plate structure according to any one of claims 1 to 9, wherein the outermost layer of the antireflection film is the low refractive index layer containing silicon oxide.

11. The glass plate structure according to any one of claims 1 to 10, wherein the number of layers of the antireflection film is 9 or less.

12. The glass plate structure according to any one of claims 1 to 11, wherein the number of layers of the antireflection film is four or more.

13. An in-vehicle display device comprising: a display panel; and the glass plate structure according to any one of claims 1 to 12, which covers the display panel.

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