JP7029912B2 - Thin glass laminate - Google Patents

Description

The present invention relates to a thin glass laminate.

Conventionally, a glass laminate composed of a glass material and a resin film such as an optical film has been used for a member constituting an image display device, for example, a substrate of a display element, a sealing material of an organic EL element, a front protective plate, and the like. Has been done. In recent years, image display devices have been made lighter and thinner, and there is a tendency for them to be more flexible, and it is required to use a glass laminate made of a thinner glass material. Originally, glass materials have poor handleability due to their fragility, and as the thickness increases, the problem becomes more prominent. In particular, in a glass laminate configured by arranging a glass material on the outermost layer, there is a problem that cracks are likely to occur when the glass material is bent (particularly when the glass material side is made convex and bent). It is generally known that this is because stress is concentrated in a wedge-shaped dent when the glass is bent. However, even if this wedge-shaped dent can be made small, it is impossible in principle to obtain a completely smooth surface.

Patent No. 4122139

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to prevent breakage due to bending of thin glass due to the smoothness of the end face of thin glass and the shape of the end face, and bending durability. An object of the present invention is to provide a thin glass laminate having excellent properties.

The thin glass laminate of the present invention comprises a resin film and a thin glass arranged at least above the resin film, and the thickness of the thin glass is 30 μm to 150 μm, and at least one of the end faces of the thin glass. The portion is composed of a slope extending downward and outward and / or a curved surface.
In one embodiment, at the upper end of the thin glass, at least a part of the end face is composed of a slope or a curved surface extending downward and outward.
In one embodiment, at least a part of the end face of the thin glass is composed of a slope extending downward and outward, and an angle θ ₁ formed by the upper surface of the thin glass and the slope extending downward and outward is 90. Greater than ° and 140 ° or less.
In one embodiment, the thin glass has an upward curved surface that is convex outward as the curved surface at least a part of the end surface thereof, the upward curved surface is the curved surface, and the upward curved surface is the curved surface (curved surface). It is a curved surface in which the angle θ ₂ formed by the contact surface A and the upper surface of the thin glass at the height h1) × 3/4 is larger than 90 °.
In one embodiment, the angle θ ₂ is greater than 90 ° and less than or equal to 140 °.
In one embodiment, the thin glass further has a downward curved surface that is convex outward as the curved surface at least a part of the end face thereof.
In one embodiment, at least a portion of the end face of the thin glass is composed of the slope and / or the curved surface and the vertical surface.
In one embodiment, in the thin glass, the height H1 of the portion formed by the slope or the curved surface whose end surface extends downward and outward is 0.1% or more with respect to the thickness of the thin glass. Is.
In one embodiment, the ratio of the height H1 of the portion where the end face is formed of the slope or the curved surface extending downward and outward to the height H2 of the portion where the end face is formed of the vertical plane. (H1: H2) is 1: 9 to 9.99: 0.01.
In one embodiment, the arithmetic average surface roughness Ra of the end face of the thin glass is 150 nm or less.
In one embodiment, the 10-point average roughness Rz of the end face of the thin glass is 500 nm or less.
In one embodiment, the resin film is arranged so as to protrude from the thin glass.
In one embodiment, the step generated between the resin film and the thin glass is 200 μm or less in a cross-sectional view.
In one embodiment, the resin film is an optical film.
In one embodiment, the optical film is a polarizing plate.
In one embodiment, the resin film has a transparent conductive layer.
In one embodiment, the thin glass and the resin film are laminated via an adhesive.
According to another aspect of the present invention, there is provided a method for manufacturing the thin glass laminate. In this manufacturing method, thin glass and a resin film are laminated to form a laminate A, the laminate A is cut to a predetermined size, and then the end face of the laminate B obtained by cutting is polished by polishing. Including doing.

According to the present invention, since at least a part of the end face is composed of a slope or a curved surface, it is possible to provide a thin glass laminate in which the thin glass is not easily broken and has excellent bending durability.

It is a schematic cross-sectional perspective view of the thin glass laminated body by one Embodiment of this invention. FIG. 3 is an enlarged cross-sectional view of an end portion of a thin glass laminate according to one embodiment of the present invention. It is a schematic cross-sectional perspective view of the thin glass laminated body by one Embodiment of this invention. FIG. 3 is an enlarged cross-sectional view of an end portion of a thin glass laminate according to one embodiment of the present invention. It is a schematic cross-sectional perspective view of the thin glass laminated body by one Embodiment of this invention. FIG. 3 is an enlarged cross-sectional view of an end portion of a thin glass laminate according to one embodiment of the present invention.

A. Overall Structure of Thin Glass Laminate The thin glass laminate of the present invention comprises a resin film and a thin glass arranged at least above the resin film, and the thin glass is at least a part of the end face of the thin glass. Is composed of a slope and / or a curved surface extending downward and outward. The thin glass laminate of the present invention has a slope or a curved surface extending downward and outward on at least a part of the end face of the thin glass, so that the thin glass is not easily damaged and has excellent bending durability. It is considered that this is because when the thin glass laminate is bent, the force applied to the thin glass laminate is dispersed by the slope or curved surface extending downward and outward, and the local load is reduced. Further, this effect becomes more remarkable when the end face includes a curved surface. Hereinafter, a typical configuration of the thin glass laminate of the present invention will be specifically described with reference to FIGS. 1 to 6.

FIG. 1 is a schematic cross-sectional perspective view of a thin glass laminate according to one embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of an end portion of the thin glass laminate shown in FIG. The thin glass laminate 100 according to this embodiment includes a resin film 10 and thin glass 20 arranged on at least one surface (upper side) of the resin film 10. The thin glass 20 includes a slope 21 extending downward and outward on at least a part of the end face of the thin glass 20. In one embodiment, the thin glass 20 and the resin film 10 can be laminated via any suitable adhesive or pressure-sensitive adhesive (not shown). Further, on the surface of the resin film 10 on which the thin glass 20 is arranged, it is preferable that the entire surface thereof is covered with the thin glass 20 (that is, the end portion of the resin film 10 and the end portion of the thin glass 20 coincide with each other. It is preferable to do). In the present specification, for convenience, the thin glass 20 side (upper side of the paper surface) of the thin glass laminate 100 is on the upper side, and the resin film 10 side (lower side of the paper surface) is on the lower side. It does not limit the usage.

The angle θ ₁ formed by the upper surface 23 of the thin glass 20 and the slope 21 extending downward and outward is preferably larger than 90 °, more preferably larger than 90 ° and 150 ° or less, and more preferably larger than 90 ° and 140 °. It is the following, and more preferably 92 ° to 140 °. Within such a range, the effect of the present invention becomes more remarkable. The thin glass may have a plurality of downward and outwardly extending slopes having different slopes. In one embodiment, the thin glass may further have an inwardly extending slope (not shown). For example, at the lower end of the thin glass 20, a slope extending downward and inward may be formed at least a part of the end face. The angle θ _1'between the lower surface of the thin glass and the slope extending downward and inward is preferably larger than 90 °, more preferably larger than 90 ° and 150 ° or less, and more preferably 92 ° to 140 °.

FIG. 3 is a schematic cross-sectional perspective view of a thin glass laminate according to one embodiment of the present invention. FIG. 4 is an enlarged cross-sectional view of an end portion of the thin glass laminate shown in FIG. In the thin glass laminate 100'according to this embodiment, the thin glass 20 includes a curved surface 22 at least a part of the end face of the thin glass 20. The curved surface 22 is preferably configured to be convex outward as shown in the illustrated example. Further, the curved surface constituting the end face of the thin glass 20 may be a curved surface having a constant curvature or a set of curved surfaces defined by an arbitrary curvature (having a plurality of curved surfaces having different curvatures). May be). Hereinafter, in the present specification, a curved surface composed of a continuous one curve having a constant curvature in cross-sectional view is referred to as a “one curved surface”. Therefore, "a set of curved surfaces defined by an arbitrary curvature" can be rephrased as "a set of one curved surface".

In one embodiment, the thin glass 20 has a height of at least a part of its end face, with respect to a portion (height h1 of the curved surface 22) × 3/4 of the curved surface 22 (with respect to the lower end side 22b of the curved surface 22). A curved surface in which the angle θ ₂ formed by the contact surface A and the upper surface 23 of the thin glass at (where the height is h1 × 3/4) is larger than 90 ° (hereinafter, such a curved surface is referred to as an “upward curved surface”). Have. The angle θ ₂ is preferably larger than 90 ° and 150 ° or less, more preferably larger than 90 ° and 140 ° or less, and further preferably 92 ° to 140 °. Within such a range, the effect of the present invention becomes remarkable.

FIG. 5 is a schematic cross-sectional view of a thin glass laminate according to one embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view of an end portion of the thin glass laminate shown in FIG. In the thin glass laminate 100 ″ according to this embodiment, the thin glass 20 includes an upward curved surface 22 and a downward curved surface 24 on at least a part of the end face of the thin glass 20. The downward curved surface 24 is a curved surface 24 (height h1'x 1/4 of the curved surface 24) x 1/4 (height is h1'x 1/4 with respect to the lower end side 24b of the curved surface 24). An angle θ ₃ formed by the contact surface B and the lower surface 25 of the thin glass means a curved surface larger than 90 °. The angle θ ₃ is preferably larger than 90 ° and 150 ° or less, and more preferably 92 ° to 140 °. Within such a range, bending resistance can be maintained. The downward curved surface is also preferably convex outward.

In one embodiment, as shown in FIGS. 1-6, at the upper end of the thin glass 20, at least a part of the end face is composed of a slope 21 or a curved surface 22 (preferably an upward curved surface) extending downward and outward. There is. In such an embodiment, the upper end sides 21a and 22a of the slope 21 or the curved surface 22 extending downward and outward are in contact with the thin glass upper surface 23. With such a configuration, a local load is reduced at the upper end of the thin glass, which is a portion that is fragile and receives a larger force at the time of bending, and a thin glass laminate that is more difficult to break can be obtained.

In one embodiment, as shown in FIGS. 1-6, the thin glass 20 is composed of a slope and / or a curved surface and a vertical surface 25 extending downward and outward at least a part of its end face. The vertical surface 25 means a surface substantially perpendicular to the upper surface 23 of the resin film 10, and the angle formed by the vertical surface 25 and the upper surface 23 is preferably 85 ° to 95 °, more preferably 85. ° to 90 °. This is acceptable because the glass is thin. In one embodiment, as shown in FIGS. 1 and 3, above the thin glass 20, the end face is composed of a slope 21 or an upward curved surface 22 whose end face extends downward and outward, and below, the end face is composed of a vertical surface 25. Ru. In another embodiment, as shown in FIG. 5, the thin glass 20 has an upward curved surface 22, a vertical surface 25, and a downward curved surface 24 in this order from above. If the end face of the thin glass is configured to include a slope or curved surface extending downward and outward, the effect of forming a slope or curved surface extending downward and outward without unnecessarily reducing the amount of glass material is effective. It is possible to obtain a thin glass laminate that is exhibited and has more excellent bending durability. The resin film may be arranged so as to protrude or retract from the thin glass. In this case, a step is generated between the resin film and the thin glass in a cross-sectional view, but the step is preferably small. The step generated between the resin film and the thin glass is preferably 200 μm or less, and more preferably 100 μm or less.

The plan-view shape of the thin glass (and the thin glass laminate) can be any suitable shape. In the plan view of thin glass, the angle formed by the adjacent sides may or may not be a right angle. Further, the adjacent sides may be connected by a curve. Further, the plan view shape of the thin glass may be defined by a straight line, a curved line having an arbitrary appropriate curvature, or a straight line and a curved line. The thin glass may be circular. This is because the bending resistance of the glass is not constrained by the shape of the surface as long as the end surface of the present invention is in a preferable range.

In the present invention, the entire circumference of the thin glass may have a slope or a curved surface (preferably an upward curved surface) whose end face extends downward and outward as described above, and the above is described in a part around the thin glass. It may have a slope or a curved surface (preferably an upward curved surface) whose end face extends downward and outward. Further, when the thin glass laminate has a rectangular shape, it may have a slope or a curved surface (preferably an upward curved surface) whose end faces extend downward and outward as described above on its four sides, and a set of facing sides. In, it may have a slope or a curved surface (preferably an upward curved surface) extending downward and outward as described above. When an end face has a slope or a curved surface (preferably an upward curved surface) extending downward and outward in a set of facing sides, the side is preferably a bent side. Further, the thin glass 20 may have both a slope and a curved surface extending downward and outward at one end surface.

In the thin glass, the height H1 of the portion composed of the slope or the curved surface extending downward and outward is preferably 0.1% or more, more preferably 10% or more with respect to the thickness of the thin glass. It is more preferably 20% or more, still more preferably 40% or more. In one embodiment, the upper limit of H1 is 100%. In another embodiment, H1 is preferably less than 100%, more preferably 99.9% or less, still more preferably 90% or less, still more preferably 80% or less. Within such a range, a thin glass laminate that is not easily damaged can be obtained. "Height H1 of a portion whose end face is composed of a slope or a curved surface extending downward and outward" means the total height of the slope and the curved surface extending downward and outward. It should be noted that the portion other than the portion where the end face is composed of a slope or a curved surface extending downward and outward may be a portion where the end surface is composed of a vertical surface.

The height H1 of the portion where the end face is composed of a slope or a curved surface extending downward and outward, and the height H2 of the portion where the end face is composed of a vertical surface (that is, the height obtained by subtracting H1 from the thickness of the thin glass). The ratio (H1: H2) to and to (H1: H2) is preferably 1: 9 to 10: 0, more preferably 1: 9 to 9.99: 0.01, and more preferably 2: 8 to 9: 1. Yes, more preferably 4: 6 to 6: 4. Within such a range, a thin glass laminate that is not easily damaged can be obtained.

The radius of curvature of the curved surface is preferably 50 μm to 1500 μm, and more preferably 50 μm to 1000 μm. Within such a range, a thin glass laminate that is not easily damaged can be obtained. The curved surface may be uniquely determined or may be composed of a set of arbitrary curvatures.

The central angle α of the fan shape including the curve constituting the curved surface (1 curved surface) is preferably 5 ° to 95 °, more preferably 10 ° to 90 °, and further preferably 30 ° to 90 °. .. Within such a range, a thin glass laminate that is not easily damaged can be obtained.

The thickness of the thin glass is preferably 30 μm to 150 μm, and most preferably 50 μm to 100 μm. Within such a range, a thin glass laminate having excellent flexibility can be obtained without impairing the physical properties (hardness, CTE, barrier property, etc.) of the thin glass.

The thickness of the resin film can be set to an arbitrary appropriate thickness depending on the intended use. The thickness of the resin film is, for example, 10 μm to 500 μm, preferably 30 μm to 200 μm.

The lower limit of the ratio of the thickness of the resin film to the thickness of the thin glass (thickness of the resin film / thickness of the thin glass) is preferably 0.2 or more. Within such a range, it is possible to prevent the thin glass from scattering. The upper limit of the ratio of the thickness of the resin film to the thickness of the thin glass (thickness of the resin film / thickness of the thin glass) is preferably 5 or less. Within such a range, the stress applied to the glass surface can be tolerated even when the thin glass is bent as convex. The ratio of the thickness of the resin film to the thickness of the thin glass (thickness of the resin film / thickness of the thin glass) is more preferably 0.3 to 3. Within such a range, even if the thin glass is broken when the thin glass laminate is handled, it is possible to prevent the thin glass from being damaged.

The thin glass laminate may include any other suitable layer. For example, any suitable other layer is placed on the surface opposite the thin glass resin film. Examples of such a layer include a layer having a thickness of 100 μm or less, and specific examples thereof include a protective film temporarily arranged to prevent foreign matter from adhering to the surface of thin glass and contamination. Further, the surface of the glass may include a functional layer such as a transparent electrode, an antireflection layer, and an antifouling layer. The thickness of the functional layer is preferably 1 μm or less.

In one embodiment, the thin glass laminate is configured without arranging other layers on the surface of the thin glass opposite to the resin film (that is, the thin glass is the outermost layer). ). A thin glass laminate composed of thin glass located on the outermost layer tends to break easily, and in particular, it tends to break easily when the thin glass side is convex and bent. The thin glass laminate of the present invention is excellent in bending durability even if the thin glass is configured on the outermost surface layer.

B. Thin glass The shape of the thin glass is typically plate-shaped. According to the classification according to the composition, the thin glass includes, for example, soda-lime glass, borosilicate glass, aluminosilicate glass, quartz glass and the like. Further, according to the classification according to the alkaline component, non-alkali glass and low-alkali glass can be mentioned. The content of the alkali metal component (for example, Na ₂ O, K ₂ O, Li ₂ O) of the thin glass is preferably 15% by weight or less, and more preferably 10% by weight or less.

The total light transmittance of the thin glass at a wavelength of 550 nm is preferably 90% or more. The refractive index _ng of the thin glass at a wavelength of 550 nm is preferably 1.4 to 1.6.

The average coefficient of thermal expansion of the thin glass is preferably 10 ppm ° C ^-1 to 0.5 ppm ° C ^-1 , and more preferably 7 ppm ° C ^-1 to 0.5 ppm ° C ^-1 .

The density of the thin glass is preferably 2.3 g / cm ³ to 3.0 g / cm ³ , and more preferably 2.3 g / cm ³ to 2.7 g / cm ³ .

The arithmetic average surface roughness Ra of the end face of the thin glass is preferably 150 nm or less, more preferably 130 nm, and further preferably 110 nm or less. The lower limit of the arithmetic average surface roughness Ra of the end face of the thin glass is, for example, 10 nm or more.

The 10-point average roughness Rz of the end face of the thin glass is preferably 500 nm or less, more preferably 450 nm or less, and further preferably 400 nm or less. The lower limit of the 10-point average roughness Rz of the end face of the thin glass is, for example, 200 nm or more.

Any suitable method can be adopted as the method for forming the thin glass. Typically, the thin glass melts a mixture containing a main raw material such as silica and alumina, a defoaming agent such as sardine glass and antimony oxide, and a reducing agent such as carbon at a temperature of 1400 ° C to 1600 ° C. Then, it is formed into a thin plate and then cooled to produce it. Examples of the thin plate forming method for the thin glass include a slot down draw method, a fusion method, and a float method. The thin glass formed into a plate shape by these methods may be chemically polished with a solvent such as hydrofluoric acid, if necessary, in order to make the thin glass into a thin plate or to improve the smoothness.

As the thin glass, a commercially available thin glass may be used as it is, or a commercially available thin glass may be polished to a desired thickness and used. Examples of commercially available thin glass include Corning's "7059", "1737" or "EAGLE2000", Asahi Glass's "AN100", NH Techno Glass's "NA-35", and Nippon Electric Glass's "OA-". 10 ”,“ D263 ”or“ AF45 ”manufactured by Schott AG, and the like.

C. Resin film In one embodiment, an optical film is used as the resin film. Examples of the optical film include a polarizing plate (an optical film having a polarizing function), a retardation plate, and an isotropic film. The resin film may have a single-layer structure or a multi-layer structure.

Any suitable material is used as the material constituting the resin film. Examples of the material constituting the resin film include polyvinyl alcohol (PVA) -based resin, polyolefin-based resin, cyclic olefin-based resin, polycarbonate-based resin, cellulose-based resin, polyester-based resin, polyamide-based resin, polyimide-based resin, and poly. Ether-based resin, polystyrene-based resin, (meth) acrylic-based resin, (meth) acrylic urethane-based resin, polysulfone-based resin, acetate-based resin, epoxy-based resin, silicone-based resin, polyallylate-based resin, polysulfone-based resin, polyether Examples thereof include imide-based resins, epoxy-based resins, urethane-based resins, and silicone-based resins.

The elastic modulus of the resin film at 23 ° C. is preferably 1.5 GPa to 10 GPa, more preferably 1.8 GPa to 9 GPa, and further preferably 1.8 GPa to 8 GPa. Within such a range, it is possible to obtain a thin glass laminate that is highly effective in protecting the thin glass and is not easily damaged. The elastic modulus in the present invention can be measured by a tensile test.

In one embodiment, the resin film has a transparent conductive layer. A resin film with a transparent conductive layer is configured by arranging a transparent conductive layer on the resin film. Examples of the transparent conductive layer include a metal oxide layer, a metal layer, a layer containing a conductive polymer, a layer containing metal nanowires, a layer composed of a metal mesh, and the like.

D. Protective film In one embodiment, the protective film is placed on the outer surface of the thin glass. The protective film temporarily protects the thin glass and prevents foreign matter and the like from adhering to the thin glass. Examples of the material constituting the protective film include polyethylene, polyvinyl chloride, polyethylene terephthalate, polyvinylidene chloride, polypropylene, polyvinyl alcohol, polyester, polycarbonate, polystyrene, polyacrylonitrile, ethylene vinyl acetate copolymer, and ethylene-vinyl alcohol. Examples thereof include polymers, ethylene-methacrylic acid copolymers, nylons, cellophane, silicone resins and the like.

E. Method for manufacturing a thin glass laminate In one embodiment, the thin glass laminate is formed by laminating thin glass and a resin film to form a laminate A, and after cutting the laminate A to a predetermined size, the thin glass laminate A is formed. It can be obtained by polishing the end portion (end face) of the laminated body B obtained by cutting.

In one embodiment, the laminate A is formed by laminating the resin film and the thin glass via an adhesive. As the adhesive, any suitable adhesive is used. Examples of the adhesive include an adhesive containing a resin having a cyclic ether group such as an epoxy group, a glycidyl group, and an oxetanyl group, an acrylic resin, and a silicone resin. Preferably, a UV curable adhesive is used.

In another embodiment, the laminate A can be formed by applying a resin solution onto thin glass.

Any suitable method can be adopted as the cutting method of the laminated body A. Examples of the cutting method include a method of cutting using a full back, a UV laser, a water jet, an end mill, or the like.

The crack length of the end face of the laminated body B is preferably 10 μm to 300 μm, and more preferably 10 μm to 200 μm. The crack length means the maximum value of the length component in the direction perpendicular to the end face of the crack when the laminated body B is viewed from the upper surface.

Polishing is preferably adopted as a method for polishing the end face of the laminated body B. Polishing is a method in which a polishing pad is pressed against the end face of the laminated body B to cause relative movement, and when the polishing pad is moved relative to each other, a slurry containing free abrasive grains is supplied to the surface to be processed to polish the end face. .. In the present invention, by performing policing, it is possible to form an end face having a slope and / or a curved surface extending downward and outward as described above.

Preferably, the end face of the laminated body B is polished in a state where the laminated body B is sandwiched between another plate glass or a resin plate. By doing so, on the thin glass surface, the slurry penetrates into the upper part of the thin glass by pushing the polishing cloth on the glass surface side, and the pushing effect by the polishing cloth is reduced on the resin film side of the thin glass. It is possible to satisfactorily form an end face having a slope and / or a curved surface extending downward and outward as described above.

A nylon brush is preferably used as the polishing cloth used for polishing. The diameter of the brush is preferably 0.1 mm to 0.5 mm, more preferably 0.1 mm to 0.3 mm.

As the free abrasive grains, for example, cerium oxide, silicon oxide, indium oxide and the like can be used. In particular, it is preferable to use cerium oxide because the silicon component of the glass and cerium also cause a substitution reaction, so that the glass can be cut while being melted. The particle size of the free abrasive grains is preferably about 1 μm to 5 μm.

The polishing amount at the time of polishing is preferably 300 μm or less, more preferably 200 μm or less, and further preferably 100 μm or less. If the target amount of polishing is too large, a thin glass laminate having a desired shape may not be obtained, and for example, a nylon brush may cause a problem such as peeling off the interface between the resin layer and the glass.

In the thin glass laminate obtained by polishing the laminate B, the arithmetic average roughness Ra of the glass portion is preferably 150 nm or less, more preferably 130 nm, and further preferably 110 nm or less. The lower limit of the arithmetic average roughness Ra of the glass portion is, for example, 10 nm or more. The 10-point average roughness Rz of the glass portion is preferably 500 nm or less, more preferably 450 nm or less, and further preferably 400 nm or less. The lower limit of the 10-point average roughness Rz of the glass portion is, for example, 200 nm or more.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The evaluation methods in the examples and comparative examples are as follows.

[Production Example 1] Preparation of thin glass / resin film laminate (laminate A) A resin film is adhered to a 100 μm thick thin glass (manufactured by Nippon Denki Glass Co., Ltd., trade name “OA-10”) with an adhesive (epoxy-based). A thin glass / resin film laminate (laminate A) was prepared by laminating via a UV curable adhesive (thickness: 10 μm). As the resin film, a film formed by laminating a polarizing element having a thickness of 5 μm and an acrylic film having a thickness of 40 μm was used. Further, the resin film was laminated so that the acrylic film faced the thin glass.

[Example 1]
The laminated body A was cut by a dicing device (manufactured by Shoda Tektron Co., Ltd., trade name "CCM-550A type") to obtain a laminated body B. The cutting conditions were such that both ends of the sample were fixed, and a blade having a diameter of 200 mm and a blade count of Danyamond abrasive grain # 325 was used for cutting at a rotation speed of 3000 rpm and a speed of 40 mm / min (size: 60 mm × 120 mm).
Next, 15 laminated bodies B were laminated, the upper and lower portions thereof were sandwiched between flat glass (60 mm × 120 mm) having a thickness of 500 μm, and the peripheral portion 4 was used by a policing device (manufactured by Shoda Tektron Co., Ltd., trade name “BPM-380C”). The edges were treated with end faces to obtain a thin glass laminate.
In the end face treatment, a 6-inch diameter roll made of a nylon brush having a diameter of 0.2 mm is rotated (rotation speed 900 rpm, brush contact amount: 5 mm), and the end face is polished with the nylon brush while supplying a polishing liquid. did. As the polishing liquid, a polishing liquid containing cerium oxide particles (particle size: 2 μm to 3 μm) in water was used. The final polishing amount was 100 μm.

[Example 2]
A surface protective film (RP207, manufactured by Nitto Denko KK) was attached to the thin glass surface of the laminate A, and then cut and polished in the same manner as in Example 1 to obtain a thin glass laminate.

[Comparative Example 1]
The laminate A was cut with a UV laser (wavelength 355 nm, pulse width 15 ps, speed 1000 mm / s, number of scans 100 times) to obtain a thin glass laminate.

[Comparative Example 2]
After rough cutting the laminated body A with a cutting machine, 15 sheets are laminated and end face treated with a rotary cutting blade (XAL series carbide square end mill 2 blades / blade length 3D type manufactured by MISUMI) to form a thin glass laminated body. Got The cutting conditions were such that the depth of cut was 0.5 mm, the rotation speed was 25,000 rpm, and the speed was 1500 mm / s.

[Comparative Example 3]
The laminate A was cut with a dicing device (CCM-550A type manufactured by Shoda Techtron Co., Ltd.) to obtain a thin glass laminate. The cutting conditions were such that both ends of the sample were fixed, and a blade having a diameter of 200 mm and a blade count of Danyamond abrasive grain # 325 was used for cutting at a rotation speed of 3000 rpm and a speed of 40 mm / min.

[evaluation]
The thin glass laminates obtained in Examples and Comparative Examples (in Example 2 the thin glass laminate after the protective film was peeled off) were subjected to the following evaluation. The results are shown in Table 1.
(1) Shape evaluation The cross section of the thin glass laminate was observed by SEM, and the end face shape (presence or absence of a curved surface formed above the thin glass; the curvature of the curved surface; the curved surface (height h1 of the curved surface) × 3/4. The angle θ ₂ ) between the contact surface A and the upper surface of the thin glass was measured. In the thin glass laminates of Comparative Examples 1 to 3, no curved surface was formed on the end surface of the thin glass, and the angle formed by the upper surface and the vertical surface was 90 °.
In addition, the arithmetic average surface roughness Ra and the arithmetic average surface roughness Ra of the end face of the thin glass were measured by AFM (field of view: 50 μm □).
(2) Bending strength A two-point bending test was performed on a thin glass laminate (size: 60 mm × 110 mm) so that the long side was bent, and the distance between the two points when cracked was measured. The distance between two points is the distance between one end in the long side direction and the other end, and means a distance that becomes shorter as the thin glass laminate is bent starting from the central portion in the length direction. do. Further, the narrower the distance between the two points, the higher the bending strength.

As is clear from Table 1, by forming a predetermined curved surface on the end face of the thin glass, a thin glass laminate having excellent bending durability can be obtained.

10 Resin film
20 thin glass
100 thin glass laminate

Claims (17)

The optical film and the thin glass arranged at least above the optical film are provided.
The optical film is a polarizing plate, a retardation plate, or an isotropic film.
The thickness of the thin glass is 30 μm to 150 μm, and the thickness is 30 μm to 150 μm.
At least a part of the end face of the thin glass is composed of a slope extending downward and outward and / or a curved surface.
Thin glass laminate. The thin glass laminate according to claim 1, wherein at least a part of the end face at the upper end of the thin glass is composed of a slope or a curved surface extending downward and outward. At least a part of the end face of the thin glass is composed of a slope extending downward and outward.
The angle θ ₁ formed by the upper surface of the thin glass and the slope extending downward and outward is larger than 90 ° and 140 ° or less.
The thin glass laminate according to claim 1 or 2. The thin glass has an upward curved surface that is convex outward as the curved surface at least a part of the end face thereof.
The upward curved surface is a curved surface in which the angle θ ₂ formed by the contact surface A at a portion of the curved surface (height h1 of the curved surface) × 3/4 and the upper surface of the thin glass is larger than 90 °.
The thin glass laminate according to claim 1. The thin glass laminate according to claim 4, wherein the angle θ ₂ is larger than 90 ° and 140 ° or less. The thin glass laminate according to claim 4 or 5, wherein the thin glass further has a downward curved surface that is convex outward as the curved surface on at least a part of the end face thereof. The thin glass laminate according to any one of claims 1 to 6, wherein at least a part of the end face of the thin glass is composed of a slope extending downward and outward and / or a curved surface and a vertical surface. From claim 1, the height H1 of the portion of the thin glass formed by the slope or the curved surface whose end surface extends downward and outward is 0.1% or more with respect to the thickness of the thin glass. 7. The thin glass laminate according to any one of 7. The ratio (H1: H2) of the height H1 of the portion formed by the slope or the curved surface whose end surface extends downward and outward to the height H2 of the portion formed by the vertical surface of the end surface is The thin glass laminate according to claim 7 or 8, which is 1: 9 to 9.99: 0.01. The thin glass laminate according to any one of claims 1 to 9, wherein the arithmetic average surface roughness Ra of the end face of the thin glass is 150 nm or less. The thin glass laminate according to any one of claims 1 to 10, wherein the 10-point average roughness Rz of the end face of the thin glass is 500 nm or less. The thin glass laminate according to any one of claims 1 to 11, wherein the optical film is arranged so as to protrude from the thin glass. The thin glass laminate according to any one of claims 1 to 12, wherein the step generated between the optical film and the thin glass is 200 μm or less in a cross-sectional view. The thin glass laminate according to any one of claims 1 to 13, wherein the optical film is a polarizing plate. The thin glass laminate according to any one of claims 1 to 14, wherein the optical film has a transparent conductive layer. The thin glass laminate according to any one of claims 1 to 15, wherein the thin glass and the optical film are laminated via an adhesive. It includes laminating thin glass and an optical film to form a laminate A, cutting the laminate A to a predetermined size, and then polishing the end face of the laminate B obtained by cutting by polishing.
The method for producing a thin glass laminate according to any one of claims 1 to 16.

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