Cover element and method for producing a cover element

Abstract

The present invention relates to a cover member 10 comprising a first glass 21, a first resin 30 which is a thermoplastic resin or a thermoplastic elastomer, and a second resin 40 which is provided between a side surface 21C of the first glass 21 and a side surface 30C1 of the first resin 30 and bonds the first glass 21 and the first resin 30 together, wherein the second resin 40 is a different resin from the first resin 30 and the loss modulus G'' at 35 °C is 10 6 Pa or more.

Description

TECHNICAL FIELD

[0001] The present invention relates to a cover element and a method for producing a cover element. STATE OF THE ART

[0002] There is a case where it is necessary to impart flexibility to a cover member arranged to protect a protective target, such as a display. For example, Patent Document 1 describes a cover member that can be bent using a UV (ultraviolet) curable resin as a starting point by providing the UV-curable resin between glasses arranged in a lateral direction. DOCUMENT LISTPATENT DOCUMENTS

[0003] Patent document 1: US 2021 / 0107251 SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0004] However, in the case where the UV-curable resin is provided between the glasses as in Patent Document 1, it is necessary to fill an entire area to which flexibility is to be imparted with the UV-curable resin, and a step of filling with an uncured resin and a step of curing the filled resin during manufacturing require time and effort. Furthermore, in a cover member in which a glass and a resin are bonded together, a bonded portion may be peeled off due to repeated bending. Therefore, it is necessary to prevent breakage and peeling of the bonded portion due to bending while simplifying a manufacturing process.

[0005] An object of the present invention is to provide a cover member and a method for manufacturing a cover member which can prevent breakage and peeling of a joined portion due to bending. SOLUTION TO THE PROBLEM

[0006] A cover member according to the present disclosure is a cover member of a display, comprising: a first glass; a first resin which is a thermoplastic resin or a thermoplastic elastomer; and a second resin which is provided between a side surface of the first glass and a first side surface of the first resin and is configured to bond the first glass and the first resin, wherein the second resin is a resin different from the first resin and has a loss modulus G'' of 10 6 Pa or more at 35 °C.

[0007] A cover member according to the present disclosure comprises: a first glass; a first resin; and a second resin provided between a side surface of the first glass and a side surface of the first resin and configured to bond the first glass and the first resin, wherein, after a bending durability test in which bending is performed 200,000 times at a bending curvature radius of 20 mm, the first resin and the second resin have no broken portion, and a bonded portion between the first resin and the second resin and a bonded portion between the first glass and the second resin are not peeled off.

[0008] A cover member according to the present disclosure is a cover member for a display, comprising: a first glass having a recessed portion in a part of a main surface; a first resin, which is a thermoplastic resin or a thermoplastic elastomer and is provided in the recessed portion; a second resin, which is provided in the recessed portion and between a side surface of the recessed portion and a first side surface of the first resin and is configured to bond the first glass and the first resin;and a third resin provided between a lower surface of the recessed portion and a main surface of the first resin and configured to bond the lower surface of the recessed portion and the main surface of the first resin, wherein the second resin is a resin different from the first resin and has a loss modulus G'' of 10; 6 Pa or more at 35 °C.

[0009] A method for manufacturing a cover member according to the present disclosure comprises: a step of applying a curable resin between a side surface of a first glass and a first side surface of a plate-shaped first resin, which is a thermoplastic resin or a thermoplastic elastomer; and a step of curing the curable resin to form a second resin having a loss modulus G'' of 10 6Pa or more at 35 °C, thereby bonding the first glass and the first resin to the second resin. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0010] According to the present invention, breakage and damage of a connected portion due to bending can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS [ Fig. 1] Fig. 1 is a cross-sectional view showing a display device according to the present embodiment. [ Fig. 2] Fig. 2 is a cross-sectional view showing a display device according to the present embodiment. [ Fig. 3] Fig. 3 is a schematic cross-sectional view of a cover element. [ Fig. 4] Fig. 4 is a schematic plan view of the cover element. [ Fig. 5A] Fig.Figure 5A is a schematic diagram showing test conditions in a three-point bending strength test. [ Fig. 5B] Fig. Figure 5B is a schematic diagram showing test conditions in a flexural fatigue test. [ Fig. 6] Fig. 6 is a schematic diagram showing a method of manufacturing a cover member according to the present embodiment. [ Fig. 7] Fig. 7 is a schematic diagram showing another example of the cover member. [ Fig. 8] Fig. 8 is a schematic diagram showing another example of the cover member. [ Fig. 9] Fig. 9 is a schematic diagram showing another example of the cover member. [ Fig. 10] Fig. 10 is a schematic diagram showing another example of the cover member. [ Fig. 11] Fig. 11 is a schematic diagram showing another example of the cover member. [ Fig. 12] Fig. 12 is a schematic diagram showing another example of the cover member. DESCRIPTION OF EMBODIMENTS

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited to the embodiment, and in the case where there are multiple embodiments, it also encompasses a combination of the embodiments. Furthermore, numerical values ​​include rounding ranges.

[0012] It should be noted that in the present embodiment, unless otherwise specified, "peeling" refers to at least one of an interface fracture of a bonded portion between bonded members and a cohesive fracture of a member corresponding to an adhesive of the bonded members. Furthermore, "fracture" refers to a crack in a bent portion when a member is bent, unless otherwise specified. Furthermore, "cloudiness" means that the resin is white and cloudy due to fatigue, unless otherwise specified. Furthermore, "damage" refers to a state where it is difficult to use as a covering member due to peeling, fracture, cloudiness, and the like, unless otherwise specified. (display device)

[0013] Fig. 1 and Fig.2 are cross-sectional views showing a display device according to the present embodiment. A display device 1 according to the present embodiment is a display device to be provided in a vehicle and is provided, for example, on a front side of a driver's seat and a passenger's seat in the vehicle. However, the display device 1 can be used not only for a vehicle application but for any application and can be provided in any position.

[0014] Hereinafter, a thickness direction (stacking direction) of the display device 1 (cover member 10) is referred to as a Z direction, a direction perpendicular to the Z direction (a left-right direction in the example in the Fig. 1) is called the X-direction and a direction perpendicular to the Z-direction and the X-direction (a direction perpendicular to the paper surface in the example in the Fig.1) is called the Y-direction. In addition, a direction along the X-direction (right direction in the example in the Fig. 1) is set as the direction X1 and the other direction along the X direction (left direction in the example in the Fig. 1) is set as the X2 direction. A direction along the Y direction (toward the back of the paper in the example in the Fig. 1) is set as the Y1 direction and the other direction along the Y direction (direction towards the front of the paper in the example in the Fig. 1) is set as the Y2 direction. One direction along the Z direction (direction from a display surface to a rear surface of the display device 1) is set as the Z1 direction, and the other direction along the Z direction (direction from the rear surface to the display surface of the display device 1) is set as the Z2 direction.

[0015] It should be noted that the Z direction here is a direction perpendicular to a main surface 10A in a state where the cover member 10 of the display device 1 is not bent and is flat, as described later (a state where the main surface 10A is mounted in contact with a flat surface).

[0016] As it is in the Fig. As shown in Figure 1, the display device 1 is bendable. The display device 1 can be bent so that the Z2 direction side with the Y direction as the bending axis is recessed. However, the bending axis and the recessing direction are not limited to this and can be arbitrary. For example, the bending axis can be any direction orthogonal to the Z direction (e.g., the X direction), or the bending can be performed so that the Z1 direction side is recessed.

[0017] It should be noted that when the display device 1 (the cover member 10) is bent, the bending axis can be assumed to be a central axis of a circle of curvature. Furthermore, "bendable" means that bending and stretching can be performed along a predetermined bending axis; in other words, bending can be performed along a predetermined bending axis through elastic deformation.

[0018] The display device 1 includes the cover member 10, a bonding layer 50, and a display panel 100. In the display device 1, the cover member 10, the bonding layer 50, and the display panel 100 are stacked in this order in the Z1 direction. The cover member 10 is provided on a surface (display surface) of the display panel 100 on the Z1 direction side and protects the display surface of the display panel 100. However, the cover member 10 is not limited to being used as a covering material of the display panel 100. A target to be protected can be any object, and the cover member can be used for any application. A structure of the cover member 10 will be described later.

[0019] The bonding layer 50 is a layer provided between the cover member 10 and the display panel 100 in the Z direction, and attaches a main surface of the cover member 10 on the Z2 direction side and a main surface (display surface) of the display panel 100 on the Z1 direction side. The bonding layer 50 is flexible. The bonding layer 50 can be formed from any flexible member that attaches the cover member 10 and the display panel 100. For example, the bonding layer 50 can be an optically transparent adhesive (OCA) or an optically transparent resin (OCR). However, the bonding layer 50 is not an essential component and may not be provided in the display device 1. (Display field)

[0020] The display panel 100 is a display that displays an image. The display panel 100 may be any display that can display an image, and examples include a liquid crystal panel, an organic EL panel, a PDP, and an electronic ink-type panel, and may include a touch panel.

[0021] The display panel 100 may be flexible, as shown in Fig. 1, or may not be bendable, as shown in the Fig. 2. In the example in the Fig.2, the display panel 100 is not provided at a bent portion (a portion of a first resin 30, which will be described later, on the Z1 direction side), but is provided at a position away from the bent portion. Specifically, a bendable panel connection layer 110 is provided at the bent portion (the portion of the first resin 30, which will be described later, on the Z1 direction side), and the display panel 100 is provided on the panel connection layer 110 on each of the X1 direction side and the X2 direction side. In this case, each display panel 100 is connected to the panel connection layer 110. The panel connection layer 110 may be any bendable member and may, for example, be the same material as the first resin 30, which will be described later.

[0022] It should be noted that examples of the bendable display panel 100 include an organic EL panel, and examples of the non-bendable display panel 100 include a liquid crystal panel. (cover element)

[0023] A cover member according to the present disclosure is a cover member for a display, comprising: a first glass; a first resin which is a thermoplastic resin or a thermoplastic elastomer; and a second resin which is provided between a side surface of the first glass and a first side surface of the first resin and is configured to bond the first glass and the first resin, wherein the second resin is a resin different from the first resin and has a loss modulus G'' of 10 6 Pa or more at 35 °C.

[0024] The cover member according to the present disclosure may further comprise a second glass, and the second resin may also be provided between a second side surface of the first resin and a side surface of the second glass for bonding the first resin and the second glass.

[0025] The Fig. 3 is a schematic cross-sectional view of the cover element and the Fig. Figure 4 is a schematic plan view of the cover member. The cover member 10 is a plate-shaped member having a main surface 10A, which is a main surface on the Z2 direction side, and a main surface 10B, which is a main surface on the Z1 direction side.

[0026] The cover member 10 is bendable. In the present embodiment, the cover member 10 is flat when the cover member 10 is arranged on a flat surface with the main surface 10A facing downward. For example, in the case where it is mounted on the display device 1 or the like, the cover member 10 is in a bent state due to elastic deformation, as shown in Fig. 1 and Fig.2. Here, the state in which the cover member 10 can be arranged flat refers to a state in which substantially the entire main surface 10A is in contact with the flat surface only by its own weight, and it can also be regarded as a state in which no external load is received and the cover member 10 is not elastically deformed by an external load. It should be noted that substantially the entire main surface 10A may mean that the entire main surface 10A is a flat surface, but is not limited thereto, and may refer, for example, to a region having 95% or more of the area of ​​the entire main surface 10A. Furthermore, the cover member 10 may be a curved surface in a state in which the cover member 10 is arranged on a flat surface.The curved surface is formed, for example, by heating and shaping a first glass 21 and a second glass 22.

[0027] Hereinafter, it is assumed that the cover member 10 is placed on a flat surface unless otherwise stated.

[0028] As it is in Fig. 3 and Fig. As shown in Fig. 4, the cover member 10 includes the first glass 21, the second glass 22, the first resin 30, and a second resin 40. The first glass 21, the second glass 22, the first resin 30, and the second resin 40 are arranged in a direction orthogonal to the Z direction and are arranged in the X direction in the example of the present embodiment. Specifically, in the present embodiment, the first glass 21, a second resin 40a as the second resin 40, the first resin 30, a second resin 40b as the second resin 40, and the second glass 22 are arranged in this order to the X1 direction.

[0029] The main surface 10A of the cover member 10 on the Z2 direction side includes a main surface 21A of the first glass 21 on the Z2 direction side, a main surface 22A of the second glass 22 on the Z2 direction side, a main surface 30A of the first resin 30 on the Z2 direction side, and a main surface 40A of the second resin 40 on the Z2 direction side. Similarly, the main surface 10B of the cover member 10 on the Z1 direction side includes a main surface 21B of the first glass 21 on the Z1 direction side, a main surface 22B of the second glass 22 on the Z1 direction side, a main surface 30B of the first resin 30 on the Z1 direction side, and a main surface 40B of the second resin 40 on the Z1 direction side. (First glass)

[0030] The first glass 21 is a plate-shaped member made of glass. The first glass 21 has the main surface 21A, which is a main surface on the Z2 direction side, the main surface 21B (main surface opposite to the main surface 21A), which is a main surface on the Z1 direction side, and a side surface 21C, which is a surface extending in a direction intersecting the Z direction. In the example of the present embodiment, the side surface 21C may also be referred to as an end surface connecting the main surface 21A and the main surface 21B. The side surface 21C of the first glass 21 on the first resin 30 side (the X1 direction side in the present example) is bonded to the second resin 40a.

[0031] In the example of the present embodiment, the first lens 21 has a rectangular shape when viewed from the Z direction. However, the shape of the first lens 21 may be any shape.

[0032] A thickness D0 of the first glass 21 is, for example, 0.4 mm or more, preferably 0.7 mm or more, more preferably 0.8 mm or more, and even more preferably 1.0 mm or more. In the case where the thickness D0 is within this range, deterioration of the bondability with the second resin 40 due to the first glass 21 being too thin can be prevented. Moreover, the thickness D0 of the first glass 21 is preferably 0.7 mm or more and 5.0 mm or less, more preferably 0.8 mm or more and 3.0 mm or less, and even more preferably 1.0 mm or more and 2.0 mm or less. In the case where the upper limit of the thickness D0 is within this range, a bonding area between the first glass 21 and the second resin 40 can be prevented from being excessively large, and a manufacturing process can be simplified.Moreover, in the case where the upper limit of the thickness D0 is within this range, an excessive increase in stress generated when the second resin 40 is bent can be reduced, and damage can be prevented.

[0033] It should be noted that the thickness D0 refers to a distance in the Z direction from the main surface 21A to the main surface 21B of the first glass 21.

[0034] A refractive index n d of the first glass 21 is preferably 1.47 or more and 1.55 or less, and more preferably 1.49 or more and 1.53 or less. In the case where the refractive index n d is within this range, light from the display device can be visually detected by a user in a suitable manner.

[0035] It should be noted that the refractive index n drefers to a refractive index at a d-line of helium (wavelength: 587.6 nm). The refractive index n d can be measured using a V-block method.

[0036] A Young's modulus of the first glass 21 is preferably 60 GPa or more, and more preferably 70 GPa or more. Furthermore, the Young's modulus of the first glass 21 is preferably 60 GPa or more and 95 GPa or less, and more preferably 70 GPa or more and 90 GPa or less. When the Young's modulus of the first glass 21 is within this range, damage can be appropriately prevented. The Young's modulus of each member comprising the first glass 21 can be obtained by a tensile test (JIS K7161, JIS K7113).

[0037] The first glass 21 is preferably a tempered glass, such as a chemically tempered glass.

[0038] In the case where the first glass 21 is a chemically strengthened glass, the thickness (DOL) of a compressive stress layer of the first glass 21 is, for example, preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. Furthermore, the thickness (DOL) of the compressive stress layer is, for example, preferably 180 μm or less, and more preferably 50 μm or less.

[0039] A surface compressive stress (CS) of the compressive stress layer is preferably 500 MPa or more, more preferably 650 MPa or more, and even more preferably 750 MPa or more. An upper limit is not specifically limited, and the CS is preferably 1200 MPa or less, for example.

[0040] As a method for obtaining chemically strengthened glass by subjecting a glass to chemical strengthening treatment, a known method can be used. Examples of a molten salt used for the chemical strengthening treatment include alkali nitrate salts, alkali sulfate salts, and alkali chloride salts, such as potassium nitrate, sodium nitrate, potassium sulfate, and sodium sulfate. These molten salts are not limited to sole use; a plurality of types of molten salts can be used in combination, and other salts can be mixed to adjust the chemical strengthening properties. Accordingly, in a surface layer of the first glass 21, alkali ions (Li ions or Na ions) are ion-exchanged (substituted) with other alkali ions (Na ions or K ions) having a larger ionic radius in the molten salt, followed by cooling to approximately normal temperature.Through this ion exchange, a layer (compressive stress layer) in which compressive stress is generated due to high density is formed on the surface layer of the first glass 21. Consequently, the first glass 21 can be toughened. Treatment conditions, such as a temperature of the molten salt and an immersion time, can be adjusted so that the compressive stress value (CS) of the compressive stress layer and the thickness (DOL) of the compressive stress layer have desired values.

[0041] The first glass 21 which has been subjected to the chemical strengthening treatment may further be subjected to an acid treatment and an alkali treatment.

[0042] The acid treatment is a treatment in which the first glass 21 subjected to the chemical strengthening treatment is immersed in an acid solution. Accordingly, Na and / or K on the surface of the first glass 21 subjected to the chemical strengthening treatment are replaced with H. That is, a surface layer of the compressive stress layer in the first glass 21 subjected to the chemical strengthening treatment is changed into a low-density layer having a low density.

[0043] The alkali treatment is a treatment in which the first glass 21, which has undergone the acid treatment, is immersed in a basic solution. Accordingly, part or all of the low-density layer formed by the acid treatment is removed. Consequently, cracks or latent scratches present on the surface of the first glass 21 can be removed along with the low-density layer.

[0044] A material of the first glass 21 can be any material, and examples thereof include a soda-lime glass and an aluminosilicate glass (a SiO2-Al2O3-Na2O-based glass or a SiO2-Al2O3-Li2O-Na2O-based glass). Of these, an aluminosilicate glass is preferable in view of strength.

[0045] Examples of the material of the first glass 21 include: a glass material containing, in mol% as oxides, 50% or more and 80% or less of SiO2, 1% or more and 20% or less of Al2O3, 6% or more and 20% or less of Na2O, 0% or more and 11% or less of K2O, 0% or more and 15% or less of MgO, 0% or more and 6% or less of CaO, and 0% or more and 5% or less of ZrO2; and a glass material containing, in mol% as oxides, 50% or more and 80% or less of SiO2, 2% or more and 25% or less of Al2O3, 0.1% or more and 20% of Li2O, 0.1% or more and 18% or less of Na2O, 0% or more and 10% or less of K2O, 0% or more and 15% or less of MgO, 0% or more and 5% or less of CaO, 0% or more and 5% or less of P2O5, 0% or more and 5% or less of B2O3, 0% or more and 5% or less of Y2O3, and 0% or more and 5% or less of ZrO2.

[0046] In addition, as the material of the first glass 21, a chemical strengthening glass based on an aluminosilicate glass (for example, “Dragontrail (registered trademark)” manufactured by AGC Inc.) can also be suitably used. (Second glass)

[0047] The second glass 22 is a plate-shaped member made of glass. The second glass 22 has the main surface 22A, which is a main surface on the Z2 direction side, the main surface 22B (main surface opposite to the main surface 22A), which is a main surface on the Z1 direction side, and a side surface 22C, which is a surface extending in the direction intersecting the Z direction. In the example of the present embodiment, the side surface 22C can also be regarded as an end surface connecting the main surface 22A and the main surface 22B. The side surface 22C of the second glass 22 on the first resin 30 side (the X2 direction side in the present example) is bonded to the second resin 4.

[0048] Since the properties of the second glass 22 are identical to those of the above-described first glass 21, their description is omitted. For example, a thickness, refractive index, Young's modulus, and composition of the second glass 22 may be identical to those of the first glass 21. Similarly to the first glass 21, the second glass 22 may be a tempered glass, such as a chemically tempered glass, and its properties and chemically tempering method may be identical to those of the first glass 21. (First resin)

[0049] The first resin 30 is a member that forms a bent portion of the cover member 10. The first resin 30 has the main surface 30A, which is a main surface on the Z2 direction side, the main surface 30B (the main surface opposite to the main surface 30A), which is a main surface on the Z1 direction side, and a side surface 30C, which is a surface extending in the direction intersecting the Z direction. The side surface 30C can be considered an end surface connecting the main surface 30A and the main surface 30B.In the first resin 30, a side surface 30C1 (first side surface), which is the side surface 30C on the first glass 21 side (the X2 direction side in the present example), is bonded to the second resin 40a, and a side surface 30C2 (second side surface), which is the side surface 30C on the second glass 22 side (the X1 direction side in the present example) is bonded to the second resin 40b.

[0050] That is, as it is in the Fig. As shown in Figure 4, the first resin 30 is provided to be positioned between the first glass 21 and the second glass 22 in the X direction and to extend in the Y direction. Therefore, in the example of the present embodiment, the cover member 10 can be bent with the first resin 30 as the starting point of bending and the Y direction as the bending axis.

[0051] The first resin 30 is preferably a member made of a thermoplastic resin or a thermoplastic elastomer. The first resin 30 may be made of any thermoplastic resin or any thermoplastic elastomer. A main component thereof is preferably at least one or more selected from a polyester, an acrylic resin, a polyethylene (PE), and a polycarbonate (PC). The main component is more preferably a polyester, and the main component is even more preferably a polyethylene terephthalate (PET). Examples of the acrylic resin include polymethyl methacrylate (PMMA). The main component here means that the content, based on the entire first resin 30, is 50 mass% or more and 100 mass% or less, preferably 70 mass% or more and 100 mass% or less, more preferably 90 mass% or more and 100 mass% or less, and even more preferably 100 mass%.

[0052] By forming the first resin 30 with such a member, the manufacturing process can be simplified. That is, for example, by using a thermoplastic member as the first resin 30, it is possible to manufacture the cover member 10 by bonding the sheet-shaped first resin 30, which is sufficiently cured at normal temperature, with the second resin 40. Therefore, a step of filling with an uncured resin and a step of curing the filled resin are not required for the first resin 30, and the manufacturing process can be simplified. Further, in a cover member for vehicle application with a large area, it is necessary to enlarge the bent portion, and it is particularly preferable to form the bent portion with the first resin 30 in advance because the filling step and the curing step can be omitted in the large portion.By forming the first resin 30 with such a member, breakage and clouding of the bent portion due to repeated bending can be prevented.

[0053] The first resin 30 preferably contains a member having a tensile modulus of elasticity of 2000 MPa or more and 4000 MPa or less as a main component, more preferably contains a member having a tensile modulus of elasticity of 2100 MPa or more and 3900 MPa or less as a main component, and even more preferably contains a member having a tensile modulus of elasticity of 2200 MPa or more and 3800 MPa or less as a main component. By using a member having a tensile modulus of elasticity within this range, damage to the bent portion due to repeated bending can be better prevented. It should be noted that the tensile modulus of elasticity can be measured based on ISO 527-1 and ISO 527-2.

[0054] A glass transition temperature Tg of the first resin 30 is preferably 60°C or higher and 200°C or lower, more preferably 65°C or higher and 195°C or lower, and even more preferably 70°C or higher and 190°C or lower. By using the first resin 30 with the glass transition temperature Tg within this range, the cover member 10 can be manufactured using the sufficiently cured first resin 30, and thus the manufacturing process can be simplified.

[0055] In the case where the display panel is installed under the first resin 30 as shown in the Fig. 1, and in the case where the display panel is not installed under the first resin 30 as shown in the Fig.As shown in Figure 2, the first resin 30 is preferably transparent to visible light if it is desired to improve the uniform appearance of the cover member. For example, the first resin 30 preferably has an external transmittance of 70% or more for light having a wavelength of 550 nm.

[0056] It should be noted that external transmittance can be measured using a general spectrophotometer. The intensity I0 of a luminous flux is measured in a state where a sample is not placed. Then, the sample is placed on the measuring luminous flux, and the intensity IT of the luminous flux transmitted through the sample is measured. Using this, the external transmittance T can be measured according to the following equation (1). T=100⋅IT / I0

[0057] The refractive index n dof the first resin 30 preferably closer to the refractive index n d of the first glass 21 and is preferably greater than the refractive index n d of the first glass 21. The refractive index n d of the first resin 30 is preferably 1.30 or more and 1.70 or less, and more preferably 1.40 or more and 1.60 or less. In the case where the refractive index n d is within this range, the light from the display device can be recognized in a suitable manner by the user.

[0058] A difference between the refractive index n d of the first resin 30 and the refractive index n d of the first glass 21 is preferably 0.001 or more and 0.15 or less, more preferably 0.003 or more and 0.1 or less, and even more preferably 0.005 or more and 0.05 or less.

[0059] On the other hand, in the case where the display panel 100 is not installed under the first resin 30 as shown in the Fig. 2, since the first resin 30 is colored, an effect of concealing wiring or the like of the display panel 100 from the user can be provided. In this case, the first resin 30 is black, for example, and may have a pattern such as a wood grain pattern or a marble pattern.

[0060] A thickness D1 of the first resin 30 is preferably 0.7 mm or more, more preferably 0.8 mm or more, and even more preferably 1.0 mm or more. In the case where the thickness D1 is within this range, a reduction in bondability with the second resin 40 due to the first resin 30 being too thin can be prevented. Moreover, the thickness D1 of the first resin 30 is preferably 0.7 mm or more and 5.0 mm or less, more preferably 0.8 mm or more and 3.0 mm or less, and even more preferably 1.0 mm or more and 2.0 mm or less. In the case where the upper limit of the thickness D1 is within this range, a bonding area can be prevented from being excessively large, and the manufacturing process can be simplified.

[0061] It should be noted that the thickness D1 refers to a distance in the first resin 30 in the Z direction from the main surface 30A on the Z2 direction side to the main surface 30B on the Z1 direction side.

[0062] A difference between the thickness D1 of the first resin 30 and the thickness D0 of the first glass 21 is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 60 μm or less. With such a small difference in thickness, a step between the first resin 30 and the first glass 21 can be reduced. It should be noted that in the case of providing a third glass 23 on the main surface 30A of the first resin 30, as shown in FIG. Fig. 8, which will be described later, a total value of the thickness of the first resin 30 and the thickness of the third glass 23 can be treated as the thickness D1 of the first resin 30.

[0063] A width W1 of the first resin 30 is preferably 2.0 cm or more, more preferably 3.0 cm or more and 15 cm or less, and even more preferably 4.0 cm or more and 10 cm or less. In the case where the width W1 is 2.0 cm or more, the bent portion can be sufficiently enlarged and the cover member 10 can be bent in an appropriate manner. Moreover, by forming such a relatively large bent portion with the first resin 30, a step of filling with an uncured resin is not required, which is also preferable from the viewpoint of simplifying the manufacturing process. Furthermore, in the case where the width W1 is 10 cm or less, the bent portion can be prevented from being too large, and the visibility of the image can be improved.

[0064] It should be noted that the width W1 refers to a distance in a direction in which the first resin 30, the second resin 40, and the first glass 21 are arranged, and refers to a distance in the X direction from the side surface 30C1 to the side surface 30C2. (Second Harz)

[0065] The second resin 40 is a member that joins the first glass 21 (or the second glass 22) and the first resin 30. The second resin 40 has the main surface 40A, which is a main surface on the Z2 direction side, the main surface 40B (the main surface opposite to the main surface 40A), which is a main surface on the Z1 direction side, and a side surface 40C, which is a surface extending in the direction intersecting the Z direction. It can be considered that the side surface 40C is an end surface that joins the main surface 40A and the main surface 40B.

[0066] In the present embodiment, the second resin 40a, which bonds the first glass 21 and the first resin 30, and the second resin 40b, which bonds the second glass 22 and the first resin 30, are provided as the second resin 40. The second resin 40a is provided between the first glass 21 and the first resin 30 in the X direction, and bonds the side surface 21C of the first glass 21 on the X1 direction side and the side surface 30C1 of the first resin 30 on the X2 direction side. That is, in the second resin 40a, a side surface 40C1 on the first glass 21 side (the X2 direction side in the present example) is bonded to the side surface 21C of the first glass 21 on the X1 direction side, and a side surface 40C2 on the first resin 30 side (the X1 direction side in the present example) is bonded to the side surface 30C1 of the first resin 30.Accordingly, the second resin 40b is provided between the first resin 30 and the second glass 22 in the X direction, and connects the side surface 30C2 of the first resin 30 on the X1 direction side and the side surface 22C of the second glass 22 on the X2 direction side. That is, in the second resin 40b, the side surface 40C1 on the first resin 30 side (the X2 direction side in the present example) is connected to the side surface 30C2 of the first resin 30, and the side surface 40C2 on the second glass 22 side (the X1 direction side in the present example) is connected to the side surface 22C of the second glass 22 on the X2 direction side.

[0067] Properties of the second resin 40 are described below and, unless otherwise stated, refer to the properties of both second resins 40a and 40b.

[0068] The second resin 40 is preferably a resin that is different from the first resin 30. That is, the second resin 40 preferably has a composition that is different from that of the first resin 30. A loss modulus G'' of the second resin 40 at normal temperature (35 °C) is preferably 10 6 Pa or more, more preferably 3.0 × 10 6 Pa or more and 2.0 × 10 15 Pa or less and more preferably 4.0 × 10 6 Pa or more and 1.0 × 10 15Pa or less. In the case where the loss modulus G'' of the second resin 40 is within this range, cohesive failure of the second resin 40 can be prevented, durability against a tensile force during repeated bending can be improved, the first resin 30 and the first glass 21 (or the second glass 22) are bonded to each other in an appropriate manner, and peeling at a bonded portion due to bending can be prevented. The bonded portion here refers to a bonded portion between the first resin 30 and the second resin 40 or a bonded portion between the second resin 40 and the first glass 21 (or the second glass 22).

[0069] It should be noted that the loss modulus G'' can be measured, for example, under the following measurement conditions using a dynamic viscoelasticity measuring device (e.g., DVA-200, manufactured by IT Instrumentation and Control Co., Ltd.). In the case where repeated bending is performed, a tensile stress is repeatedly generated in the second resin 40 between the first resin 30 and the first glass 21. In the dynamic viscoelasticity measurement, viscoelastic properties can be obtained accordingly when a tensile force is periodically applied to the sample, and predominantly the values ​​of the loss modulus G'', a storage modulus G', and tan δ are obtained. Specifically, the loss modulus G'' represents a viscosity term and represents the ease of outward distribution of the stress generated by the tensile force.Therefore, the loss modulus G'' can be used to determine the ease of cohesive failure of the second resin 40 even when repeated bending is performed.

[0070] The measurement conditions for the loss modulus G'' can be, for example, as follows. The second resin 40 is cut into a strip shape with a thickness of 1 mm, a long side of 30 mm, and a short side of 2 mm, and an end portion of the long side is placed between the fixing portions of the device. The measurement is performed in a tensile mode at a measurement temperature of 35°C to 50°C (1°C interval) and a measurement frequency of 1 Hz.

[0071] The second resin 40 is preferably a resin obtained by curing a curable resin. Here, the curable resin refers to a resin that is in a liquid state exhibiting fluidity before curing, and is cured and solidified through a predetermined step. That is, it can be considered that the second resin 40 is a cured body of a curable resin in a liquid state exhibiting fluidity. Here, examples of the predetermined step include heating or irradiation with light (for example, ultraviolet rays), and in other words, examples of the curable resin include a thermosetting resin and a photocurable resin (for example, a UV-curable resin).

[0072] The second resin 40 may be a cured body of any thermosetting resin, and the main component is preferably at least one or more selected from a cured acrylic resin and a cured epoxy resin. Examples of the acrylic resin include an amino resin acrylate, a copolymer acrylate, a polyester acrylate, and an epoxy acrylate. Examples of the epoxy resin include a bisphenol-type epoxy resin, an alicyclic epoxy resin, and a glycidyl ether epoxy resin. By forming the second resin 40 with such a member, the first resin 30 and the first glass 21 (or the second glass 22) can be bonded to each other in a suitable manner, and peeling at the bonded portion due to bending can be prevented.

[0073] It should be noted that the main component here means that the content based on the entire second resin 40 is 50 mass% or more and 100 mass% or less, preferably 70 mass% or more and 100 mass% or less, more preferably 90 mass% or more and 100 mass% or less, and even more preferably 100 mass%.

[0074] The second resin 40 preferably contains a member having a tensile elastic modulus of 50 MPa or more and 2000 MPa or less as a main component, more preferably contains a member having a tensile elastic modulus of 100 MPa or more and 1900 MPa or less as a main component, and even more preferably contains a member having a tensile elastic modulus of 150 MPa or more and 1800 MPa or less as a main component. By using a member having a tensile elastic modulus within this range, peeling can be suitably prevented.

[0075] Furthermore, the second resin 40 preferably contains a member having an elongation at break of 20% or more as a main component, more preferably contains an element having an elongation at break of 25% or more as a main component, and even more preferably contains an element having an elongation at break of 30% or more as a main component. By using an element having an elongation at break within this range, peeling can be suitably prevented. The elongation at break is a ratio of "a difference between a length of the second resin 40 in a tensile direction at break and a length of the second resin 40 in the tensile direction without load" to "the length of the second resin 40 in the tensile direction without load" (length difference / length without load) in the measurement of tensile modulus of elasticity.

[0076] A glass transition temperature Tg of the second resin 40 is preferably -100°C or higher and lower than 60°C, more preferably -95°C or higher and 55°C or lower, and even more preferably -90°C or higher and 50°C or lower. By using the second resin 40 with the glass transition temperature Tg within this range, the first resin 30 and the first glass 21 can be bonded to each other in a suitable manner, and peeling due to bending can be prevented.

[0077] In the cover member, the first resin preferably has a glass transition temperature Tg of 60 °C or higher and 200 °C or lower, and the second resin preferably has a glass transition temperature Tg of -100 °C or higher and lower than 60 °C.

[0078] In the case where the display panel is installed under the second resin 40 as shown in the Fig.1, and in the case where the display panel is not installed under the second resin 40, the second resin 40 is preferably transparent to visible light in the case where it is desired to improve the appearance of uniformity of the cover member. For example, the second resin 40 preferably has an external transmittance of 70% or more for light having a wavelength of 550 nm.

[0079] In the cover member, the first resin and the second resin are preferably transparent to visible light.

[0080] A refractive index n d of the second resin 40 is preferably close to the refractive index n d of the first glass 21 and is preferably greater than the refractive index n d of the first glass 21. Furthermore, the refractive index n d of the second resin 40 is preferably a value between the refractive index n dof the first glass 21 and the refractive index n d of the first resin 30. In the case where the refractive index n d of the second resin 40 an intermediate value between the refractive index of the first glass 21 and the refractive index n d of the first resin 30, the refractive index changes continuously and the bonded portion can be visually recognized with a lower probability. The refractive index n d of the second resin 40 is preferably 1.30 or more and 1.70 or less, and more preferably 1.40 or more and 1.60 or less. In the case where the refractive index n d is within this range, the light from the display device can be recognized by the user in a suitable manner.

[0081] On the other hand, in the case where the display panel 100 is not installed under the second resin 40, if the second resin 40 is colored, the effect of concealing the wiring or the like of the display panel 100 from the user can be provided. In this case, the second resin 40 is black, for example, and may have a pattern such as a wood grain pattern or a marble pattern.

[0082] A thickness D2 of the second resin 40 is preferably 0.7 mm or more, more preferably 0.8 mm or more, and even more preferably 1.0 mm or more. In the case where the thickness D2 is within this range, a reduction in bondability with the first resin 30 or a glass due to the second resin 40 being too thin can be prevented. Moreover, the thickness D2 of the second resin 40 is preferably 0.7 mm or more and 5.0 mm or less, more preferably 0.8 mm or more and 3.0 mm or less, and even more preferably 1.0 mm or more and 2.0 mm or less. In the case where the upper limit of the thickness D2 is within this range, a bonding area can be prevented from being excessively large and the manufacturing process can be simplified.

[0083] It should be noted that the thickness D2 refers to a distance in the second resin 40 in the Z direction from the main surface 40A on the Z2 direction side to the main surface 40B on the Z1 direction side.

[0084] A width W2 of the second resin 40 is preferably 10 μm or more and 3000 μm or less, more preferably 20 μm or more and 2000 μm or less, and even more preferably 30 μm or more and 1000 μm or less. When the width W2 is within this range, the size of the bonded portion can be prevented from being excessively large while bonding the first resin 30 or the glass in a suitable manner.

[0085] It should be noted that the width W2 refers to a distance in a direction in which the first resin 30, the second resin 40, and the first glass 21 are arranged, and refers to a distance in the X direction from the side surface 40C1 to the side surface 40C2. (Relationship between the first resin and the second resin)

[0086] Next, a relationship between the first resin 30 and the second resin 40 will be described.

[0087] As described above, the first resin 30 and the second resin 40 are different resins. The first resin 30 and the second resin 40, which are different resins, can be examined using Fourier transform infrared spectroscopy (FT-IR). Specifically, the infrared transmittances of the first resin 30 and the second resin 40 are measured at each wavenumber using a microscopic Fourier transform infrared spectrometer FT-IR (for example, Nic-plan / Nicolet 6700 manufactured by Thermo Fisher Scientific Inc.). The horizontal axis is plotted as the wavenumber, and the vertical axis is plotted as the infrared transmittance or absorbance. Infrared transmittance waveforms of the first resin 30 and the second resin 40 are acquired. Then, the infrared transmittance waveform of the first resin 30 and the infrared transmittance waveform of the second resin 40 are compared with a spectrum library.Accordingly, in the case where combinations of peak positions are different, it is found that the first resin 30 and the second resin 40 are different resins. Furthermore, in the case where the first resin 30 contains a polyester, its infrared light transmittance waveform preferably has peaks derived from an ester group at a position at a wavenumber of 1705 cm. -1 or more and 1725 cm -1 or less, a position at a wavenumber of 1230 cm -1 or more and 1250 cm -1 or less and a position at a wavenumber of 1085 cm -1 or more and 1105 cm -1 or less.

[0088] In the case where the first resin 30 contains a polycarbonate, its infrared light transmittance waveform preferably has peaks derived from a carbonate group at a position at a wavenumber of 1760 cm -1 or more and 1780 cm-1 or less, a position at a wavenumber of 1200 cm -1 or more and 1220 cm -1 or less, a position at a wavenumber of 1180 cm -1 or more and 1200 cm -1 or less and a position at a wavenumber of 1150 cm -1 or more and 1170 cm -1 or less.

[0089] In the case where the first resin 30 contains an acrylic resin, its infrared light transmittance waveform preferably does not have a peak derived from a methyl group at a position at a wavenumber of 2800 cm -1 or more and 3000 cm -1 or less, no peak derived from an ester group at a position at a wavenumber of 1715 cm -1 or more and 1735 cm -1 or less, nor at a position at a wavenumber of 1135 cm -1 or more and 1155 cm -1or less, no peak derived from a benzene ring, and no peak at a position at a wavenumber of 1800 cm -1 or more and 2500 cm -1 or less.

[0090] The infrared transmittance waveform of the second resin 40 may have a plurality of peaks at the peak positions of the first resin 30, but the combination of the peak positions when viewed in the entire spectrum is preferably different from that of the first resin 30. The combination of peaks can be determined by a known method or technique. For example, the infrared transmittance waveform can be compared with the spectrum library, and the positions of the peak characteristics of the functional groups and the peaks paired due to stretching and bending vibration disclosed in Hiroshi Horiguchi, N.B. Colthup, "Introduction to Infrared and Raman Spectroscopy," Third Edition, Infrared Absorbing Review, and the like can be determined.It should be noted that in the case where the infrared light transmittance waveform of the first resin 30 has a peak at a position (wavenumber) not included in the infrared light transmittance waveform of the second resin 40, or in the case where the infrared light transmittance waveform of the second resin 40 has a peak at a position (wavenumber) not included in the infrared light transmittance waveform of the first resin 30, it can be considered that the combination of peak positions is different between the infrared light transmittance waveform of the first resin 30 and the infrared light transmittance waveform of the second resin 40.

[0091] It should be noted that FT-IR measurement conditions can be measured using either a transmission method or an ATR method. In the transmission method, a sample is irradiated with infrared light, and a spectrum is calculated based on the transmitted light. In the ATR method, a prism with a high refractive index in the infrared range is used, and a spectrum is calculated based on the reflected light that has undergone total internal reflection from the sample surface.

[0092] As described above, the first resin 30 and the second resin 40 are different resins. The first resin 30 and the second resin 40, which are different resins, can also be examined by Raman spectroscopy. Specifically, Raman scattered light of the first resin 30 and the second resin 40 is measured at each wavenumber by a microscopic Raman spectrometer (for example, LabRAM HR Evolution, manufactured by Horiba, Ltd.), the horizontal axis is plotted as the wavenumber, and the vertical axis is plotted as the scattering intensity, and Raman spectra of the first resin 30 and the second resin 40 are acquired. Then, the Raman spectrum of the first resin 30 and the Raman spectrum of the second resin 40 are compared with a spectrum library. Accordingly, in the case where combinations of peak positions are different, it is found that the first resin 30 and the second resin 40 are different resins.

[0093] Further, in the case where the first resin 30 contains a polyester, its Raman spectrum preferably has a peak resulting from an ester group at a position at a wavenumber of 1715 cm -1 or more and 1735 cm -1 or less, and a peak originating from a benzene ring at a position at a wavenumber of 1600 cm -1 or more and 1725 cm -1 or less.

[0094] In the case where the first resin 30 contains a polycarbonate, its Raman spectrum preferably exhibits peaks derived from a carbonate group at a position at a wavenumber of 1760 cm -1 or more and 1780 cm -1 or less, a position at a wavenumber of 1225 cm -1 or more and 1245 cm -1 or less and a position at a wavenumber of 880 cm -1 or more and 900 cm -1or less, a peak derived from a benzene ring at a position at a wavenumber of 1600 cm -1 or more and 1725 cm -1 or less, and a peak derived from a methyl group at a position at a wavenumber of 2960 cm -1 or more and 2970 cm -1 or less.

[0095] In the case where the first resin 30 contains an acrylic resin, its Raman spectrum preferably does not have a peak derived from a methyl group at a position at a wavenumber of 2800 cm -1 or more and 3000 cm -1 or less, no peak derived from an ester group at a position at a wavenumber of 1715 cm -1 or more and 1735 cm -1 or less, no peak derived from a benzene ring, and no peak at a position at a wavenumber of 1800 cm -1 or more and 2500 cm -1or less.

[0096] The Raman spectrum of the second resin 40 may have a plurality of peaks at the peak positions of the first resin 30, but the combination of peak positions when viewed across the entire spectrum is preferably different from that of the first resin 30. The combination of peaks can be determined by a known method or technique. For example, the Raman spectrum can be compared with the spectrum library, and the positions of the peaks characteristic of the disclosed functional groups and the peaks paired due to stretching and bending vibration can be determined.It should be noted that in the case where the Raman spectrum of the first resin 30 has a peak at a position (wavenumber) not included in the Raman spectrum of the second resin 40, or in the case where the Raman spectrum of the second resin 40 has a peak at a position (wavenumber) not included in the Raman spectrum of the first resin 30, it can be considered that the combination of peak positions is different between the Raman spectrum of the first resin 30 and the Raman spectrum of the second resin 40.

[0097] It should be noted that the measurement conditions of microscopic Raman spectroscopy are as follows: A sample surface is irradiated with a monochromatic laser at 532 nm or 785 nm, and Raman scattered light, which is scattered by molecular vibration to a wavelength different from that of the incident light, is passed through a spectroscope to calculate a spectrum.

[0098] A loss modulus G" of the first resin 30 is preferably larger than the loss modulus G" of the second resin 40. For example, a ratio of the loss modulus G" of the second resin 40 to the loss modulus G" of the first resin 30 (loss modulus G" of the second resin 40 / loss modulus G" of the first resin 30) is preferably 20% or less, more preferably 15% or less, and even more preferably 10% or less. In the case where the ratio of the loss modulus G" of the second resin 40 to the loss modulus G" of the first resin 30 is within this range, the first resin 30 and the glass can be properly bonded to each other while properly preventing damage to the first resin 30, which is a bent portion.

[0099] The difference between the thickness D2 of the second resin 40 and the thickness D1 of the first resin 30 is preferably 100 µm or less, more preferably 80 µm or less, and even more preferably 60 µm or less. With such a small thickness difference, a step between the first resin 30 and the second resin 40 can be reduced.

[0100] The width W2 of the second resin 40 is preferably smaller than the width W1 of the first resin 30. For example, a ratio of the width W2 of the second resin 40 to the width W1 of the first resin 30 (width W2 / width W1) is preferably 0.006 or more and 0.2 or less, more preferably 0.008 or more and 0.18 or less, and even more preferably 0.1 or more and 0.16 or less. In the case where the ratio of the width W2 of the second resin 40 to the width W1 of the first resin 30 is within this range, the first resin 30 and the glass can be properly bonded to each other while properly preventing damage to the first resin 30, which is a bent portion. (Three-point bending strength test)

[0101] The Fig.5A is a schematic diagram showing test conditions in a three-point bending strength test. The cover member 10 formed as described above preferably has an average breaking load, obtained by measuring a breaking load ten times in a three-point bending strength test defined below, of 1.5 N or more. Further, the cover member 10 preferably has an average bending bond strength BS, calculated using the equation described below, of 15 MPa or more, more preferably 25 MPa or more and 300 MPa or less, and even more preferably 45 MPa or more and 250 MPa or less.In the case where the average flexural bond strength in the three-point flexural strength test is within this range, it can be seen that the first resin 30 and the first glass 21 are properly bonded to the second resin 40, the durability when tensile force is applied to the second resin 40a, the adhesive flexural strength at an interface between the second resin 40a and the first resin 30, and the adhesive flexural strength at an interface between the second resin 40a and the glass 21 can be greatly improved, and peeling can be prevented. Moreover, since the load is statically continuously increased and, in particular, the load at the interface becomes large, the three-point flexural strength test is a method suitable for evaluating an adhesive strength by inducing interface fracture of the second resin 40.

[0102] As it is in the Fig.As shown in Fig. 5A, in the three-point bending strength test, the cover member 10 is arranged on plates P1 and P2 such that a main surface of the plate P1 on the Z2 direction side is in contact with the main surface 21B of the first glass 21, a main surface of the plate P2 on the Z2 direction side is in contact with the main surface 30B of the first resin 30, and the main surface 40B of the second resin 40a is in an open state. The plates P1 and P2 are plate-shaped members made of SUS with a thickness of 0.5 mm. Then, a columnar shaft portion B1 is arranged to be in contact with the main surface of the plate P1 on the Z1 direction side, and a columnar shaft portion B2 is arranged to be in contact with the main surface of the plate P2 on the Z1 direction side.Specifically, the shaft portions B1 and B2 are mounted such that a distance in the X direction from a center of the second resin 40a to a center of the shaft portion B1 is identical to a distance in the X direction from the center of the second resin 40a to a center of the shaft portion B2, and a distance L in the X direction from the center of the shaft portion B1 to the center of the shaft portion B2 when viewed from the Y direction is 30 mm. It should be noted that the shaft portions B1 and B2 are members made of stainless steel and have a diameter of 5 mm.

[0103] In this state, a load is applied while a corrugated portion B3, which has the same material and shape as the corrugated portions B1 and B2, is in contact with the main surface 40A of the second resin 40a, and the load applied from the corrugated portion B3 to the main surface 40A is increased under the condition of a test speed of 5 mm / min. Then, if the stress at the breakage of the cover member 10 is defined as an average breaking load P, the average flexural bond strength BS is calculated as BS = (3 × P × L2) / (2 × W2 × D2 2 ) using the breaking load P, the width W2 of the second resin 40, the thickness D2 of the second resin 40, and the distance L between the pivot points (the distance between the shaft sections B1 and B2). (Bending fatigue test)

[0104] The Fig.5B is a schematic diagram showing test conditions in a bending durability test. Furthermore, it is preferable that no broken portion is present in the first resin 30 of the cover member 10 after performing a bending durability test specified below. The absence of the broken portion can be inspected using an optical microscope (for example, LMS-4100 manufactured by Olympus Corporation or VHX-8000 manufactured by Keyence Corporation). It can be seen that the absence of the broken portion in the first resin 30 due to repeated bending can be prevented by the absence of the broken portion in the first resin 30.

[0105] The bending fatigue test is performed under the following measurement condition 1 or 2, for example, using a stress-free U-shaped stretching device for a planar body (for example, a stress-free U-shaped stretching tester DMLHB-FS-C, manufactured by YUASA SYSTEM Co., Ltd.) using a fatigue bench tester. (Measurement condition 1)

[0106] For the cover member 10, a sample is cut out such that one end is the first glass 21 and the other end is the first resin 30. The total length of the sample is set to a short side length of 30 mm and a long side length of 300 mm, and the ratio of the lengths of the first glass 21 and the first resin 30 is set to 1:5. Note that an OCA can be attached to a surface in this case. The second resin 40 adheres between the first glass 21 and the first resin 30 in a width range of 5 mm or less.

[0107] Next, the first glass 21 and the second resin 40 are attached to the device of the measuring device, and, as shown in the Fig.As shown in Figure 5B, the first resin 30 is bent at a position 30P located 20 mm away from a bonding interface with the second resin 40 in the X direction. A radius of curvature is R20 mm, a reciprocating speed is 80 rpm, and the bending is repeated 200,000 times. (Measurement condition 2)

[0108] In the case where only the fracture fatigue strength of the first resin 30 is examined, the bending fatigue strength test can be performed by cutting only the first resin 30 to a short side length of 30 mm and a long side length of 300 mm and installing only the first resin 30 in the fixture.

[0109] In the cover member 10, the average change rate F of the visible light transmittance of the first resin 30 is preferably less than 1.5% before and after the bending durability test. When the average change rate F of the first resin 30 is less than 1.5%, clouding of the first resin 30 due to repeated bending can be prevented, and deterioration of visibility can be prevented. The average change rate F of the visible light transmittance of the first resin 30 can be calculated according to the following equation (2). F={(F0−F1) / F0}×100

[0110] Here, F0 refers to an average value of the external transmittances for light with wavelengths of 380 nm or more and 780 nm or less of the first resin 30, sampled at intervals of 2 nm before the flexural durability test. Furthermore, F1 refers to an average value of the external transmittances for light with wavelengths of 380 nm or more and 780 nm or less of the first resin 30 after the flexural durability test.

[0111] As described above, it is preferable that the cover member 10 has no broken portion in the first resin 30 after the bending durability test in which bending is performed 200,000 times at a bending curvature radius of 20 mm.

[0112] Moreover, in the cover member 10, after the bending durability test in which bending is performed 200,000 times at a bending curvature radius of 20 mm, it is preferable that the second resin 40 has no broken portion, and the bonded portion between the first resin 30 and the second resin 40 and the bonded portion between the first glass and the second resin 40 are not peeled off.

[0113] Furthermore, after performing the above bending durability test on the cover member 10, it is preferable that the first resin 30 has no broken portion, and no peeling occurs due to cohesive failure of the second resin 40 at the bonded portion between the first resin 30 and the second resin 40 and the bonded portion between the first glass 21 and the second resin 40, or due to breakage at an interface in the bonded portion between the first resin 30 and the second resin 40 and the bonded portion between the first glass 21 and the second resin 40. It can be visually recognized that the first resin 30 has no broken portion. Furthermore, the absence of a cohesive failure portion in the second resin 40 can be inspected using an optical microscope or a three-dimensional shape measuring device.Accordingly, using an optical microscope or a three-dimensional shape measuring device, it can be found that the bonded portion between the first resin 30 and the second resin 40 and the bonded portion between the first glass 21 and the second resin 40 are not peeled off. It can be seen that the breakage of the first resin and the peeling off of the second resin 40 due to repeated bending can be prevented by the absence of the broken portion in the first resin 30, the absence of the cohesive fracture portion in the second resin 40, and the absence of the interface fracture in the bonded portion with the second resin 40.

[0114] Furthermore, in the above description, the first resin is a thermoplastic resin or a thermoplastic elastomer, but is not limited to a thermoplastic resin or a thermoplastic elastomer, as long as the first resin 30 is a material that does not have a broken portion after performing the above flexural durability test. For example, the first resin may be a cured product of a thermosetting resin. In this case, the first resin may be the same material as the second resin or may be a cured product of a thermosetting resin different from the second resin.

[0115] That is, the cover member may comprise: a first glass; a first resin; and a second resin provided between a side surface of the first glass and a first side surface of the first resin and configured to bond the first glass and the first resin, wherein the first resin and the second resin may be a cured product of a curable resin, and the second resin has a loss modulus G'' of 10 6 Pa or more at normal temperature.

[0116] Furthermore, the cover member may comprise: a first glass; a first resin; and a second resin provided between a side surface of the first glass and a side surface of the first resin and configured to bond the first glass and the first resin, wherein in a bending durability test in which bending is performed 200,000 times at a bending curvature radius of 20 mm, the first resin and the second resin cannot have a broken portion, and a bonded portion between the first resin and the second resin and a bonded portion between the first glass and the second resin cannot be peeled off. (Method for manufacturing a display device)

[0117] Next, a method for manufacturing the display device 1 will be described. Fig.6 is a schematic diagram showing a method for manufacturing a cover member according to the present embodiment. In the present manufacturing method, the first glass 21, the second glass 22, and the first resin 30 are prepared (step S10). Then, a curable resin 40Z, which is the uncured second resin 40, is applied between the side surface 21C of the first glass 21 and the side surface 30C1 of the first resin 30, so that the side surface 21C and the side surface 30C1 are bonded with the curable resin 40Z. Similarly, the curable resin 40Z is applied between the side surface 22C of the second glass 22 and the side surface 30C2 of the first resin 30, so that the side surface 22C and the side surface 30C2 are bonded with the curable resin 40Z (step S12).Next, the curable resin 40Z is cured to form the second resin 40 between the side surface 21C of the first glass 21 and the side surface 30C1 of the first resin 30, and between the side surface 22C of the second glass 22 and the side surface 30C2 of the first resin 30, thereby bonding them together by the second resin 40 (step S14). Thus, the cover member 10 is manufactured. Next, the cover member 10 and the display panel 100 are bonded together with the bonding layer 50, thus manufacturing the display device 1 (step S16).

[0118] As described above, in the cover member 10 according to the present embodiment, the first glass 21 and the first resin 30 are bonded together with the second resin 40, and the second glass 22 and the first resin 30 are bonded together with the second resin 40. Since the cover member 10 has such a structure, the first glass 21 and the first resin 30 can be bonded together with the second resin 40 in a suitable manner while the cover member 10 is bent in a suitable manner by the first resin 30. (More examples)

[0119] Further examples of the structure of the cover element 10 are described. Fig. 7 to 12 are schematic diagrams showing other examples of the cover member. (Example that does not include a second glass)

[0120] As it is in the Fig.As shown in Fig. 7, the cover member 10 may have a structure including the first glass 21, the first resin 30, and the second resin 40, and may not include the second glass 22. In this case, the second resin 40 is provided between the first glass 21 and the first resin 30 in the X direction, and connects the side surface 21C of the first glass 21 on the X1 direction side and the side surface 30C1 of the first resin 30 on the X2 direction side.

[0121] In the case where the second glass 22 is not provided as described above, the preparation of the second glass 22 is not required in the manufacture of the cover member 10. In this case, the first glass 21 and the first resin 30 are prepared, the thermosetting resin 40Z is applied between the side surface 21C of the first glass 21 and the side surface 30C1 of the first resin 30, and the thermosetting resin 40Z is cured with the second resin 40 to form the second resin 40 for bonding the side surface 21C of the first glass 21 and the side surface 30C1 of the first resin 30 together.

[0122] The present disclosure also relates to a method for producing a cover member, comprising: a step of applying a curable resin between a side surface of a first glass and a first side surface of a plate-shaped first resin, which is a thermoplastic resin or a thermoplastic elastomer; and a step of curing the curable resin to form a second resin having a loss modulus G'' of 10 6 Pa or more at 35 °C, thereby bonding the first glass and the first resin to the second resin.

[0123] It should be noted that the cover member 10 may have a structure in which three or more glasses arranged in the X-direction are bonded together with the first resin 30 and the second resin 40. In this case, for example, the second resin 40, the first resin 30, the second resin 40, and another first glass 21 may be further arranged in this order to the X2 direction on the X2 direction side of the first glass 21 in the present embodiment, which is shown in the Fig. 3. That is, the glass (first glass 21), the second resin 40, the first resin 30, and the second resin 40 arranged in the X direction can be used as a constituent unit, and this constituent unit can be repeatedly arranged in the X direction. (Example that includes a third glass)

[0124] A third glass 23 may be arranged on the main surface 30A of the first resin 30. In this case, for example, as shown in the Fig. 8, a third resin 60 and the third glass 23 are arranged on the main surface 30A of the first resin 30 in this order to the Z2 direction, and the main surface 23A of the third glass 23 on the Z2 direction side is exposed. Specifically, the third resin 60 is provided between the first resin 30 and the third glass 23 in the Z direction, and connects the main surface 30A of the first resin 30 on the Z2 direction side and the main surface 23B of the third glass 23 on the Z1 direction side. That is, in the third resin 60, a main surface 60B in the Z1 direction is connected to the main surface 30A of the first resin 30, and a main surface 60A in the Z2 direction is connected to the main surface 23B of the third glass 23.

[0125] That is, the cover member according to the present disclosure may further include a third glass provided on a main surface of the first resin, and a third resin provided between the third glass and the first resin and configured to bond the third glass and the first resin.

[0126] In this way, by providing the third glass 23 on the first resin 30, the main surface of the cover member 10 on the exposed side can be covered with a glass. Therefore, the appearance of the display device 1 can be improved, and, for example, touch characteristics can be improved in the case of using the display device 1 as a touch panel. Therefore, the structure in which the third glass 23 is provided on the first resin 30 is particularly preferable. It should be noted that even in the structure in which the second glass 22 is not provided, as shown in the Fig. 7, the third glass 23 may be provided on the first resin 30 as shown in the Fig. 8 is shown.

[0127] The thickness (a length from the main surface 23A to the main surface 23B in the Z direction) of the third glass 23 is preferably smaller than the thickness D1 of the first glass 21. The thickness of the third glass 23 is preferably 6% or more and 50% or less, more preferably 8% or more and 45% or less, and even more preferably 10% or more and 40% or less, with respect to the thickness D1 of the first glass 21. In the case where the thickness of the third glass 23 is so small, the third glass 23 can be bent in an appropriate manner.

[0128] It should be noted that since the properties of the third glass 23, excluding the thickness, are identical to the properties of the first glass 21 described above, the description thereof is omitted.

[0129] The third resin 60 may be any resin that can bond the third glass 23 and the first resin 30 and that can be bent. For example, the third resin 60 may be an OCR or OCA corresponding to the bonding layer 50, or it may be the same material as the second resin 40. It should be noted that when the third resin 60 is the same material as the second resin 40, there may be no interface between the second resin 40 and the third resin 60, and the second resin 40 and the third resin 60 may be integrated with each other. The same applies to the following.

[0130] Furthermore, in the example in the Fig.8, the third glass 23 and the third resin 60 are provided between the second resin 40a and the second resin 40b in the X direction. That is, in the third glass 23, the side surface 23C1 on the X2 direction side is bonded to the side surface 40C2 of the second resin 40a, and the side surface 23C2 on the X1 direction side is bonded to the side surface 40C1 of the second resin 40b. Similarly, in the third resin 60, a side surface 60C1 on the X2 direction side is bonded to the side surface 40C2 of the second resin 40a, and a side surface 60C2 on the X1 direction side is bonded to the side surface 40C1 of the second resin 40b.

[0131] In addition, as shown in an example in the Fig.9, the third glass 23 and the third resin 60 are provided on the second resin 40 on the Z2 direction side. In this case, the third resin 60 is provided over the main surface 30A of the first resin 30 and the main surfaces 40A of the second resins 40a and 40b, and the third glass 23 is provided on the main surface 60A of the third resin 60. In this case, the third glass 23 is preferably separated from the first glass 21 and the second glass 22 in the X direction. That is, it is preferable that the side surface 21C of the first glass 21 on the X1 direction side is separated from the side surface 23C1 of the third glass 23, and the side surface 22C of the second glass 22 on the X2 direction side is separated from the side surface 23C2 of the third glass 23.

[0132] In addition, as shown in an example in the Fig.10, the third glass 23 may be provided on the first resin 30 on both the Z2 direction side and the Z1 direction side. In this case, for example, the third resin 60 and the third glass 23 are arranged in this order to the Z1 direction on the side of the main surface 30B of the first resin 30. Specifically, the third resin 60 on the first resin 30 on the Z1 direction side connects the main surface 30B of the first resin 30 on the Z1 direction side and the main surface 23A of the third glass 23 on the Z2 direction side. That is, in the third resin 60, the main surface 60A in the Z2 direction is connected to the main surface 30B of the first resin 30, and the main surface 60B in the Z1 direction is connected to the main surface 23A of the third glass 23.In the case where the third glass 23 is provided on both main surfaces of the first resin 30 in this way, the volume occupied by the first resin 30 can be reduced while flexibility, optical properties such as transmittance and refractive index of the display device 1 are closer to those of the first resin 30, so that the appearance is improved, and the rigidity can be increased by the third glass 23, so that the touch properties are suitably improved.

[0133] That is, in the cover member according to the present disclosure, the third glass and the third resin are preferably provided on one main surface and the other main surface of the first resin.

[0134] It should be noted that in the example in the Fig.10 the third resin 60 and the third glass 23 on the side of the direction Z1 between the second resin 40a and the second resin 40b in the X direction according to the Fig. 8. However, the present disclosure is not limited thereto, and the third resin 60 and the third glass 23 on the Z1 direction side may be provided on the second resin 40 on the Z1 direction side according to the Fig. 9 must be provided. (Example of providing the first resin and the second resin in a recessed portion of the first glass)

[0135] The cover member according to the present disclosure may be a cover member for a display, comprising: a first glass having a recessed portion in a part of a main surface; a first resin provided in the recessed portion and being a thermoplastic resin or a thermoplastic elastomer; a second resin provided in the recessed portion between a side surface of the recessed portion and a first side surface of the first resin and configured to bond the first glass and the first resin;and a third resin provided between a lower surface of the recessed portion and a main surface of the first resin and configured to bond the lower surface of the recessed portion and the main surface of the first resin, wherein the second resin is a resin different from the first resin and has a loss modulus G'' of 10; 6 Pa or more at 35 °C.

[0136] In the above example, a recessed portion C may be formed in the main surface of the first glass 21, and the first resin 30 and the second resin 40 may be arranged in the recessed portion C. Specifically, in the present example, as shown in the Fig.11, the recessed portion C is formed in a part of the entire main surface 21A of the first glass 21. It can be considered that the recessed portion C is a recess recessed from the main surface 21A to the Z1 direction side. The recessed portion C is formed from an end portion on the Y1 direction side to an end portion on the Y2 direction side of the first glass 21. The recessed portion C has a bottom surface 21D which is a surface on the Z1 direction side, a side surface 21C1 which is a surface on the X2 direction side, and a side surface 21C2 which is a surface on the X1 direction side.

[0137] The first resin 30, the second resin 40 and the third resin 60 are provided in the recessed portion C. In particular, as shown in the Fig.11, the third resin 60 and the first resin 30 are arranged on the lower surface 21D in this order in the Z2 direction. The third resin 60 is provided between the lower surface 21D and the first resin 30 in the Z direction and connects the lower surface 21D and the main surface 30B of the first resin 30 on the Z1 direction side. That is, in the third resin 60, the main surface 60B in the Z1 direction is connected to the lower surface 21D, and the main surface 60A in the Z2 direction is connected to the main surface 30B of the first resin 30. Moreover, the first resin 30 and the third resin 60 are provided between the second resin 40a and the second resin 40b in the X direction. That is,, in the second resin 40a, the side surface 40C1 is bonded to the side surface 21C1 of the recessed portion C, the side surface 40C2 is bonded to the side surface 30C1 of the first resin 30 and the side surface 60C1 of the third resin 60, and the main surface 40B is bonded to the bottom surface 21D. Similarly, in the second resin 40b, the side surface 40C1 is bonded to the side surface 21C2 of the recessed portion C, the side surface 40C2 is bonded to the side surface 30C2 of the first resin 30 and the side surface 60C2 of the third resin 60, and the main surface 40B is bonded to the bottom surface 21D. It should be noted that in the example in FIG. Fig.11, the first resin 30 and the third resin 60 are provided between the second resin 40a and the second resin 40b in the X direction, but are not limited thereto and may be provided on the second resin 40 on the Z1 direction side.

[0138] In the present example, the first glass 21 has a small thickness in a region where the recessed portion C is formed, and a portion where the recessed portion C is formed can be bent together with the first resin 30. In the present example, the first glass 21 can be bent by filling the recessed portion C with the first resin 30, the second resin 40, or the like in an appropriate manner while reinforcing the portion where the recessed portion C is formed.

[0139] In addition, as stated in the Fig.12, the third glass 23 may be provided on the first resin 30 provided in the recessed portion C. In this case, the third glass 23 is provided on the main surface 30A of the first resin 30 and the main surfaces 40A of the second resins 40a and 40b, and is bonded to the main surfaces 40A of the second resins 40a and 40b. It should be noted that the third resin 60 may also be provided between the third glass 23 and the first resin 30 in the Z direction. (Effects)

[0140] As described above, the cover member 10 according to a first aspect of the present disclosure is a cover member of a display and includes: the first glass 21; the first resin 30, which is a thermoplastic resin or a thermoplastic elastomer; and the second resin 40, which is provided between the side surface 21C of the first glass 21 and the side surface 30C1 (first side surface) of the first resin 30 and is configured to bond the first glass 21 and the first resin 30. The second resin 40 is a resin different from the first resin 30 and has a loss modulus G'' of 10 6Pa or more at normal temperature (35°C). According to the present disclosure, the first glass 21 and the first resin 30 can be bonded to each other with the second resin 40 in a suitable manner while the cover member 10 is bent in a suitable manner by the first resin 30. Further, by forming the first resin 30 with such a member, a step of filling with an uncured resin and a step of curing the filled resin for the first resin 30 are unnecessary, and the manufacturing process can be simplified. Moreover, by forming the second resin 40 with such a member, the first resin 30 and the first glass 21 can be bonded to each other in a suitable manner, and breakage and peeling of the bonded portion due to bending can be prevented.

[0141] The cover member 10 according to a second aspect of the present disclosure is the cover member 10 according to the first aspect, wherein the second resin 40 is preferably a cured resin of a curable resin. The first resin 30 and the first glass 21 can be bonded to each other in a suitable manner, and breakage and peeling of the bonded portion due to bending can be prevented.

[0142] The cover member 10 according to a third aspect of the present disclosure is the cover member 10 according to the first aspect or the second aspect, wherein the first resin 30 preferably has a glass transition temperature Tg of 60°C or higher and 200°C or lower, and the second resin 40 preferably has a glass transition temperature Tg of -100°C or higher and lower than 60°C. Breakage and peeling of the bonded portion can be prevented while simplifying the manufacturing process.

[0143] The cover member 10 according to a fourth aspect of the present disclosure is the cover member 10 according to any one of the first aspect to the third aspect, wherein the first resin 30 preferably contains, as a main component, at least one or more selected from a polyester, an acrylic resin, a polyethylene, and a polycarbonate. Damage and clouding of the bent portion due to repeated bending can be prevented.

[0144] The cover member 10 according to a fifth aspect of the present disclosure is the cover member 10 according to any one of the first aspect to the fourth aspect, wherein the second resin 40 preferably contains, as a main component, at least one or more selected from a cured acrylic resin and a cured epoxy resin. The first resin 30 and the first glass 21 can be bonded to each other in a suitable manner, and breakage and peeling of the bonded portion due to bending can be prevented.

[0145] The cover member 10 according to the present aspect is the cover member 10 according to any one of the first aspect to the fifth aspect, wherein an infrared light transmittance waveform of the first resin 30 measured by FT-IR and an infrared light transmittance waveform of the second resin 40 measured by FT-IR preferably have different combinations of peak positions. Breakage and peeling of the bonded portion due to bending can be prevented.

[0146] The cover member 10 according to a sixth aspect of the present disclosure is the cover member 10 according to any one of the first aspect to the fifth aspect, wherein a breaking load is preferably 1.5 N or more in a three-point bending strength test. The strength of the second resin 40 is sufficient, and breakage and peeling of the bonded portion can be suitably prevented.

[0147] The cover member 10 according to a seventh aspect of the present disclosure is the cover member 10 according to any one of the first aspect to the sixth aspect, wherein the first resin 30 preferably has no broken portion after a bending durability test in which bending is performed 200,000 times at a bending curvature radius of 20 mm. Damage to the bent portion due to repeated bending can be prevented.

[0148] The cover member 10 according to an eighth aspect of the present disclosure is the cover member 10 according to the seventh aspect, in which an average change rate of the visible light transmittance of the first resin 30 before and after the bending durability test is preferably less than 1.5%. It can be seen that the clouding of the first resin 30 due to repeated bending can be prevented, and deterioration of visibility can be prevented.

[0149] The cover member 10 according to a ninth aspect of the present disclosure is the cover member 10 according to any one of the first aspect to the eighth aspect, wherein, after a bending durability test in which bending is performed 200,000 times at a bending curvature radius of 20 mm, it is preferable that the second resin 40 has no broken portion, and a bonded portion between the first resin 30 and the second resin 40 and a bonded portion between the first glass 21 and the second resin 40 are not peeled off. Accordingly, peeling off of the bonded portion due to bending can be prevented.

[0150] The cover member 10 according to a tenth aspect of the present disclosure includes: the first glass 21; the first resin 30; and the second resin 40 provided between the side surface 21C of the first glass 21 and the side surface 30C1 (first side surface) of the first resin 30, and configured to bond the first glass 21 and the first resin 30. In the cover member 10, after a bending durability test in which bending is performed 200,000 times at a bending curvature radius of 20 mm, the first resin 30 and the second resin 40 have no broken portion, and a bonded portion between the first resin 30 and the second resin 40 and a bonded portion between the first glass 21 and the second resin 40 are not peeled off.The cover member 10 according to the present disclosure can prevent peeling at the joined portion due to bending and can prevent breakage of the first resin 30 and the third resin 40 due to repeated bending.

[0151] The cover member 10 according to an eleventh aspect of the present disclosure is the cover member 10 according to any one of the first aspect to the tenth aspect, wherein the second resin 40 preferably has a width W2 of 10 μm or more and 3000 μm or less. The size of the bonded portion can be prevented from being excessive while bonding the first resin 30 or the glass in a suitable manner.

[0152] The cover member 10 according to a twelfth aspect of the present disclosure is the cover member 10 according to any one of the first aspect to the eleventh aspect, wherein the first resin 30 preferably has a width W1 of 2 cm or more. The bent portion can be sufficiently enlarged, and the cover member 10 can be bent in an appropriate manner.

[0153] The cover member 10 according to a thirteenth aspect of the present disclosure is the cover member 10 according to any one of the first aspect to the twelfth aspect, wherein a difference between the thickness D1 of the first resin 30 and the thickness D0 of the first glass 21 is preferably 100 μm or less. Accordingly, a step between the first resin 30 and the first glass 21 can be reduced.

[0154] The cover member 10 according to a fourteenth aspect of the present disclosure is the cover member 10 according to any one of the first aspect to the thirteenth aspect, wherein the first glass 21 preferably has a thickness D0 of 0.7 mm or more. Accordingly, a reduction in bondability with the second resin 40 due to the first glass 21 being too thin can be prevented.

[0155] The cover member 10 according to a fifteenth aspect of the present disclosure is the cover member 10 according to any one of the first aspect to the fourteenth aspect, and preferably further includes the second glass 22, wherein the second resin 40 is also provided between the side surface 30C2 (second side surface) of the first resin 30 and the side surface 22C of the second glass 22 for bonding the first resin 30 and the second glass 22. Accordingly, in a suitable manner, the first resin 30 can be bent between the first glass 21 and the second glass 22 as a starting point while preventing peeling at the bonded portion between the second glass 22 and the second resin 40.

[0156] The cover member 10 according to a sixteenth aspect of the present disclosure is the cover member 10 according to the fifteenth aspect, and preferably further includes the third glass 23 provided on the main surface 30A of the first resin 30, and the third resin 60 provided between the third glass 23 and the first resin 30 and configured to bond the third glass 23 and the first resin 30. In the case where the third glass 23 is provided on the main surface 30A, the appearance of the display device 1 can be improved, and, for example, the touch characteristics can be improved in the case of using the display device 1 as a touch panel.

[0157] The cover member 10 according to a seventeenth aspect of the present disclosure is the cover member 10 according to the sixteenth aspect, in which the third glass 23 and the third resin 60 are preferably provided on one main surface 30A and the other main surface 30B of the first resin 30. In the case where the third glass 23 is provided on both surfaces of the first resin 30, the volume occupied by the first resin 30 can be reduced while maintaining flexibility, and the appearance and touch properties of the display device 1 can be suitably improved.

[0158] The cover member 10 according to an eighteenth aspect of the present disclosure is the cover member 10 according to any one of the first aspect to the seventeenth aspect, wherein the first resin 30 and the second resin 40 are preferably transparent to visible light. Accordingly, visible light can also be transmitted through the first resin 30 and the second resin 40, and the visibility of the image can be improved.

[0159] The cover member 10 according to a nineteenth aspect of the present disclosure is the cover member 10 according to the eighteenth aspect, in which a refractive index of the second resin 40 is preferably a value between a refractive index of the first glass 21 and a refractive index of the first resin 30. Accordingly, the refractive index changes continuously, and the bonded portion is less likely to be visually recognized.

[0160] The cover member 10 according to a twentieth aspect of the present disclosure is a cover member for a display, comprising: the first glass 21 having the recessed portion C in a part of the main surface 23A; the first resin 30 being a thermoplastic resin or a thermoplastic elastomer and provided in the recessed portion C; the second resin 40 provided in the recessed portion C between the side surface 21C1 of the recessed portion C and the first side surface of the first resin 30 and configured to bond the first glass 21 and the first resin 30;and the third resin 60 provided between the lower surface 21D of the recessed portion C and the main surface 30B of the first resin 30 and formed to bond the lower surface 21D of the recessed portion C and the main surface 30B of the first resin 30, wherein the second resin 40 is a resin different from the first resin 30 and has a loss modulus G'' of 10; 6 Pa or more at 35°C. According to the present disclosure, by filling the recessed portion C with the first resin 30, the second resin 40, or the like, the first glass 21 can be bent in an appropriate manner while reinforcing the portion where the recessed portion C is formed.

[0161] A method for manufacturing the cover member 10 according to a twenty-first aspect of the present disclosure includes: a step of applying the curable resin 40Z between the side surface 21C of the first glass 21 and the side surface 30C1 of the plate-shaped first resin 30, which is a thermoplastic resin or a thermoplastic elastomer; and a step of curing the curable resin 40Z to form the second resin 40 having a loss modulus G of 10 6 Pa or more at normal temperature (35°C), thereby bonding the first glass 21 and the first resin 30 to the second resin 40. According to the present manufacturing method, the cover member 10 can be manufactured that can prevent peeling at the bonded portion. (Examples) Next, examples are described. Table 1 shows the structure and evaluation results of cover glasses in examples. [Table 1] Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Bed. First glass 30 mm × 30 mm × 1.5 mm First resin No PVC PS PET PET PET PET Second Harz 107UV No No 107UV 65UV 68UV 81UV Loss modulus [Pa] of the second resin 2,16E+04 No No 2,16E+04 6,44E+04 6,93E+06 7,69E+07 Tg [°C] of the second resin -14,9 No No -14,9 -10,8 8,3 7,4 Adhesive strength BS [MPa] 21,0 - - 11,3 11,9 33,1 55,6 Difference [nd] of refractive index between the first resin and the first glass 0,145 0,145 Bew. Flexural durability test: Detachment at the connected section Replaced Replaced Replaced Replaced Replaced Not replaced Not replaced Flexural durability test: Fracture of the second resin Broken - Broken Broken Not broken Not broken Flexural durability test: Fracture of the first resin Broken Broken Not broken Not broken Not broken Not broken Flexural durability test: Extent of change in permeability (%) of the first resin 10,2 10,2 1,52 0,66 0,66 0,66 0,66 Ease of production B A A A A A A Table 1 (continued) Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Condition First glass 30 mm × 30 mm × 1.5 mm First resin PE PE PMMA PMMA PC PC Second Harz 65UV 81UV 65UV 81UV 65UV 81UV Loss modulus [Pa] of the second resin 6,93E+06 7,69E+07 6,93E+06 7,69E+07 6,93E+06 7,69E+07 Tg [°C] of the second resin -10,8 7,4 -10,8 7,4 -10,8 7,4 Adhesive strength BS [MPa] ND ND ND ND ND ND Difference [nd] of refractive index between the first resin and first glass 0,01 0,01 0,076 0,076 Evaluation Flexural durability test: Detachment at the connected section Not replaced Not replaced Not replaced Not replaced Not replaced Not replaced Flexural durability test: Fracture of the second resin Not broken Not broken Not broken Not broken Not broken Not broken Flexural durability test: Fracture of the first resin Not broken Not broken Not broken Not broken Not broken Not broken Flexural durability test: Extent of change in permeability (%) of the first resin 2,67 2,67 1,13 1,13 0,27 0,27 Ease of production A A A A A A (Example 1)

[0162] In Example 1, a first glass with a vertical length of 30 mm, a horizontal length of 30 mm, and a thickness of 1.5 mm was prepared. Dragontrail, manufactured by AGC Inc., was used as the first glass. Then, the first resin was not provided, and 107UV, manufactured by Norland, which was a UV-curable acrylic resin, was used as the second resin. The width W2 was 1 mm and the thickness D2 was 1.5 mm for the second resin. The second resin was bonded to the side surface of the first glass to obtain a cover member.

[0163] In Example 1, the loss modulus G" of the second resin and the average fracture load in the three-point bending strength test of the cover member (second resin) were measured by the methods described in the present embodiment, and the average bond strength BS was calculated. Note that the distance L between pivot points in the three-point bending strength test was 30 mm. The results are shown in Table 1.

[0164] The refractive index n d of the first resin and the refractive index n d of the first glass were measured by the method described in the present embodiment. The difference between the refractive index n d of the first resin and the refractive index n d of the first glass (refractive index n d of the first resin - refractive index n d of the first glass) is shown in Table 1. (Example 2)

[0165] In Example 2, a cover member was manufactured in the same manner as in Example 1, except that polyvinyl chloride PVC (manufactured by Hikari Co., Ltd.) was used as the first resin, the second resin was not provided, and the first resin and the first glass were directly bonded. It should be noted that since the second resin was not provided in Example 2, the loss modulus G" of the second resin and the average fracture load in the three-point flexural strength test were not measured. (Example 3)

[0166] In Example 3, a cover member was manufactured in the same manner as in Example 1, except that polystyrene PS (manufactured by Hikari Co., Ltd.) was used as the first resin, the second resin was not provided, and the first resin and the first glass were directly bonded together. Since the second resin was not provided in Example 3, the loss modulus G'' of the second resin and the average fracture load in the three-point flexural strength test were not measured. (Example 4)

[0167] In Example 4, a cover member was obtained by bonding the side surface of the first glass and the side surface of the first resin with the second resin, using PET (manufactured by Hikari Co., Ltd.) as the first resin and 107UV, a UV-curable resin manufactured by Norland, as the second resin. Note that the dimensions of the glass and the second resin were identical to those in Example 1, the dimension of the first resin was identical to that of the glass in Example 1, and the distance L between pivot points in the three-point bending strength test was 30 mm.

[0168] In Example 4, the loss modulus G" of the second resin and the fracture load in the three-point bending strength test of the cover member (second resin) were measured by the methods described in the present embodiment. The measurement results are shown in Table 1. (Example 5 to Example 13)

[0169] In Example 5 to Example 13, cover members were obtained in the same manner as in Example 4, except that the materials of the first resin and the second resin were as shown in Table 1. It should be noted that PE is a polyethylene manufactured by AS ONE Corporation, PMMA is polymethyl methacrylate manufactured by Hikari Co., Ltd., PC is a polycarbonate manufactured by Hikari Co., Ltd., and 65UV, 68UV, and 81UV are UV-curable resins manufactured by Norland. (Evaluation)

[0170] In the evaluation according to the method described in the present embodiment, a bending durability test was conducted in which bending was performed 200,000 times at a bending curvature radius of 20 mm, and it was checked whether peeling (interface fracture) occurred at the bonded portion between the second resin (the first resin in Example 1) and the first glass after the bending durability test. Using an optical microscope LEXT OLS4100 manufactured by Olympus Corporation, a three-dimensional shape of the bonded portion with the first glass was measured, and a case where a region reduced to 5% or less of the thickness of the sample existed was evaluated as peeling (interface fracture), and a case where the region did not exist was evaluated as no peeling (interface fracture).

[0171] As can be seen from Table 1, in Example 1 to Example 3, which are comparative examples in which only the first resin or only the second resin is provided, and in Example 4 and Example 5, which are comparative examples in which the loss modulus G'' of the second resin is less than 10 6 peeling occurs at the bonded portion. On the other hand, it can be seen that in Example 6 to Example 13, which are examples of the invention in which the first resin and the second resin are provided and the loss modulus G of the second resin is 10 6 or more, peeling does not occur at the bonded portion.

[0172] As optional evaluations, the fracture of the second resin, the fracture of the first resin, and the change in permeability of the first resin were evaluated after the flexural durability test. When determining the fracture of the first and second resins, a case where the resin was visually split was determined as a fracture, and a case where the resin was not visually split was determined as no fracture. The change in permeability was calculated by the method described in the present embodiment.

[0173] In addition, ease of manufacturing was evaluated as an optional rating. In Example 1, since bonding was performed using only the UV-curable resin, the burden of the coating step and the curing step was high, and thus, a B was awarded. In Examples 2 to Example 13, since a thermoplastic resin was also used, the burden of the coating step and the curing step was low, and thus, an A was awarded.

[0174] Although embodiments of the present invention have been described above, the embodiments are not limited to the contents of these embodiments. Furthermore, the above-described components should include those that can be easily conceived by a person skilled in the art, those that are substantially identical, and those within a so-called equivalence range. Furthermore, the above components can be combined in an appropriate manner. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the gist of the above-described embodiments. INDUSTRIAL APPLICABILITY

[0175] According to the present invention, a cover member and a method for manufacturing a cover member can be provided in which breakage and peeling of a joined portion due to bending can be prevented.

[0176] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to one skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention.

[0177] This application is based on a Japanese patent application (Japanese Patent Application No. 2022-210630) filed on December 27, 2022, the contents of which are incorporated herein by reference. LIST OF REFERENCE SYMBOLS 1 display device 1 display device 10 Cover element 21 First glass 22 Second glass 23 Third Glass 30 First Resin 40 Second Harz 50 connecting layer 60 Third Harz 100 display field 110 Field connection layer B1, B2, B3 wave section P1, P2 plate C Recessed section QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2021 / 0107251

[0003]

Claims

[1] Cover element for a display, the cover element comprising: a first glass; a first resin which is a thermoplastic resin or a thermoplastic elastomer; and a second resin provided between a side surface of the first glass and a first side surface of the first resin and configured to bond the first glass and the first resin, wherein the second resin is a resin different from the first resin and has a loss modulus G'' of 10 6 Pa or more at 35 °C. [2] The cover member according to claim 1, wherein the second resin is a cured resin of a curable resin. [3] The covering member according to claim 1 or 2, wherein the first resin has a glass transition temperature Tg of 60°C or higher and 200°C or lower, and the second resin has a glass transition temperature Tg of -100°C or higher and lower than 60°C. [4] The covering member according to claim 1 or 2, wherein the first resin comprises, as a main component, at least one or more selected from a polyester, an acrylic resin, a polyethylene, and a polycarbonate. [5] The covering member according to claim 1 or 2, wherein the second resin comprises as a main component at least one or more selected from a cured acrylic resin and a cured epoxy resin. [6] A covering member according to claim 1 or 2, which has an average flexural bond strength of 15 MPa or more in a three-point flexural strength test. [7] A cover member according to claim 1 or 2, wherein the first resin has no broken portion after a bending durability test in which bending is performed 200,000 times at a bending curvature radius of 20 mm. [8] The covering member according to claim 7, wherein the first resin has an average rate of change in visible light transmittance of less than 1.5% before and after the flexural durability test. [9] Cover element according to claim 1 or 2, wherein after a bending endurance test in which bending is carried out 200,000 times at a bending radius of 20 mm, the second resin has no broken section, and a bonded portion between the first resin and the second resin and a bonded portion between the first glass and the second resin are not peeled off. [10] Cover element comprising: a first glass; a first resin; and a second resin provided between a side surface of the first glass and a side surface of the first resin and configured to bond the first glass and the first resin, wherein after a bending endurance test in which bending is carried out 200,000 times at a bending radius of 20 mm, the first resin and the second resin have no broken portion, and a bonded portion between the first resin and the second resin and a bonded portion between the first glass and the second resin are not peeled off. [11] The covering member according to claim 1, 2 or 10, wherein the second resin has a width of 10 µm or more and 3000 µm or less. [12] The covering member according to claim 1, 2 or 10, wherein the first resin has a width of 2.0 cm or more. [13] The cover member according to claim 1, 2 or 10, wherein a difference between a thickness of the first resin and a thickness of the first glass is 100 µm or less. [14] A cover member according to claim 1, 2 or 10, wherein the first glass has a thickness of 0.7 mm or more. [15] Cover element according to claim 1, 2 or 10, further comprising: a second glass, where the second resin is also provided between a second side surface of the first resin and a side surface of the second glass for bonding the first resin and the second glass. [16] Cover element according to claim 15, further comprising: a third glass provided on a main surface of the first resin; and a third resin provided between the third glass and the first resin and configured to bond the third glass and the first resin. [17] The cover member according to claim 16, wherein the third glass and the third resin are provided on one main surface and the other main surface of the first resin. [18] The cover member according to claim 1, 2 or 10, wherein the first resin and the second resin are transparent to visible light. [19] The cover member according to claim 18, wherein a refractive index of the second resin is a value between a refractive index of the first glass and a refractive index of the first resin. [20] Cover element for a display, the cover element comprising: a first glass having a recessed portion in a part of a main surface; a first resin which is a thermoplastic resin or a thermoplastic elastomer and is provided in the recessed portion; a second resin provided in the recessed portion between a side surface of the recessed portion and a first side surface of the first resin and configured to bond the first glass and the first resin; and a third resin provided between a lower surface of the recessed portion and a main surface of the first resin and configured to bond the lower surface of the recessed portion and the main surface of the first resin, wherein the second resin is a resin different from the first resin and has a loss modulus G'' of 10 6 Pa or more at 35 °C. [21] A method for producing a covering element, comprising: a step of applying a curable resin between a side surface of a first glass and a first side surface of a plate-shaped first resin which is a thermoplastic resin or a thermoplastic elastomer; and a step of curing the curable resin to form a second resin having a loss modulus G'' of 10 6 Pa or more at 35 °C, thereby bonding the first glass and the first resin to the second resin.

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