Abstract: Provided is a laminated film for a foldable display, the laminated film being free of occurrence of a fold mark or a crack at a folding portion thereof, in order to provide, for example, a foldable display excellent in mass productivity, and free of a risk of causing distortion in an image displayed at a folding portion thereof after being repeatedly folded. The laminated film for a foldable display includes: a polyester film having a thickness of from 10 ?m to 100 ?m; and an adhesive layer formed on at least one surface of the polyester film, wherein the polyester film satisfies the following conditions: (1) a refractive index in a bending direction is from 1.590 to 1.620; (2) a refractive index in a folding portion direction is from 1.670 to 1.700; (3) a refractive index in a thickness direction is 1.520 or less; and (4) a density is 1.380 g/cm3 or more, wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

Abstract: Provided is a foldable display that is excellent in mass production applicability and unlikely to have image distortion at the folding portion of the display after repeated folding, as well as a mobile device equipped therewith. The foldable display contains a surface protection film and a polarizer. The surface protection film is composed of a polyester film, and the angle made by the slow axis of the polyester film with the absorption axis of the polarizer is 10 to 80°. The polyester film has a refractive index in the bending direction of 1.590 to 1.620, a refractive index in the direction of a folding portion of 1.670 to 1.700, a refractive index in the thickness direction of 1.520 or less, and a density of 1.380 g/cm3 or more, wherein the bending direction refers to a direction orthogonal to the folding portion of the polyester film to be folded.

Abstract: Provided is a polyester film for a touchscreen module substrate of a foldable display which is free of occurrence of a crack at a folding portion thereof, in order to provide a foldable display excellent in mass productivity, and free of a risk of causing distortion in an image displayed at a folding portion thereof after being repeatedly folded. The polyester film for a touchscreen module substrate of a foldable display satisfies the following conditions: (1) a refractive index in a bending direction is from 1.590 to 1.620; (2) a refractive index in a folding portion direction is from 1.670 to 1.700; (3) a refractive index in a thickness direction is 1.520 or less; and (4) a density is 1.380 g/cm or more, wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

Abstract: Provided are a polyester film, a laminated film, and the like for protecting an organic EL module of a foldable display each of which is free of occurrence of a crack at a folding portion thereof, in order to provide a foldable display excellent in mass productivity, and free of a risk of causing distortion in an image displayed at a folding portion thereof after being repeatedly folded. The polyester film for protecting an organic EL module of a foldable display satisfies the following conditions: (1) a refractive index in a bending direction is from 1.590 to 1.620; (2) a refractive index in a folding portion direction is from 1.670 to 1.700; (3) a refractive index in a thickness direction is 1.520 or less; and (4) a density is 1.380 g/cm3 or more, wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

Abstract: Provided are a foldable display that is excellent in mass production applicability, and that does not have image distortion that can appear in the folding portion after the display is repeatedly folded; and a mobile device equipped with such a foldable display. Provided are a polyester film for surface protection films and a hard coating film for surface protection films for the foldable display and mobile device. The polyester film is for foldable display surface protection films, wherein the polyester film is cut in sheet form, the polyester film has a thickness of 10 to 75 ?m, the polyester film has an intrinsic viscosity of 0.55 to 0.65 dl/g, and the amount of rise of a cut plane on at least one side of one or more cut end portions is 35 ?m or less. The hard coating film, the foldable display, and the mobile device use the polyester film for foldable display surface protection films.

Abstract: The invention provides a biaxially oriented polyester film with a good balance among moldability during hot molding, film strength and elasticity, while suppressing deposition of an oligomer (whitening) due to heating in a coating step of an adhesive resin or the like during the molding process, and which can be used to provide a molded body, a label or the like. The biaxially oriented polyester film has a content of an ester constituent unit derived from an isophthalic acid component relative to 100% by mole of all ester constituent units in the constituent polyester resin of 0.5-5.0% by mole; a haze change when heated at 150° C. for 30 minutes of 5.0% or less; a limiting viscosity of the constituent polyester resin of 0.59-0.65 dl/g; an average storage elastic modulus at 150° C. of 5.0-7.6×108 (Pa); and an acid value of 40-60 eq/ton.

Abstract: Problem: An object of the present invention is to provide a polyester film for a foldable display, the film having a hold angle in a bending direction of 155° or more and a maximum heat shrinkage at 150° C. of 1.5% or less (wherein the hold angle refers to an angle of a crease after fixing the film at room temperature for 72 hours in such a manner that a strain of 1.7% is applied to both surfaces of a bent portion of the film, and the bending direction refers to a direction that is orthogonal to a folding portion of a foldable display produced using the film.

Abstract: Provided is a hard coating film for foldable displays that does not form creases or cracks in the folding portion, and that is also excellent in reducing iridescent colors (interference mottling) caused by fine cracks in an easy-to-adhere resin layer or other layers. The hard coating film for foldable displays contains a polyester film having a thickness of 10 to 80 ?m, an easy-to-adhere resin layer, and a hard coating layer, the easy-to-adhere resin layer and the hard coating layer being stacked in this order on at least one surface of the polyester film, wherein the easy-to-adhere resin layer is a cured product of a composition containing at least one compound selected from the group consisting of titanium compounds and zirconium compounds and a polyester resin, and the polyester film having the easy-to-adhere resin layer stacked thereon but not yet having the hard coating layer stacked thereon satisfies characteristics within specific ranges.

Abstract: Provided is a hard coating film for foldable displays that does not form creases or cracks in the folding portion, and that is also excellent in reducing iridescent colors (interference mottling) caused by fine cracks in an easy-to-adhere resin layer or other layers.

Abstract: Provided are a polyester film, a laminated film, and the like for protecting an organic EL module of a foldable display each of which is free of occurrence of a crack at a folding portion thereof, in order to provide a foldable display excellent in mass productivity, and free of a risk of causing distortion in an image displayed at a folding portion thereof after being repeatedly folded. The polyester film for protecting an organic EL module of a foldable display satisfies the following conditions: (1) a refractive index in a bending direction is from 1.590 to 1.620; (2) a refractive index in a folding portion direction is from 1.670 to 1.700; (3) a refractive index in a thickness direction is 1.520 or less; and (4) a density is 1.380 g/cm3 or more, wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

Abstract: Provided is a transparent conductive polyester film for a foldable display which is free of occurrence of a fold mark or a tear at a folding portion thereof to be used in a foldable display excellent in mass productivity, and free of a risk of causing distortion in an image displayed at a folding portion thereof, and a mobile device. The transparent conductive polyester film for a foldable display includes: a polyester film; and a transparent conductive layer laminated on at least one surface of the polyester film, wherein the polyester film satisfies the following conditions: (1) a refractive index in a bending direction is from 1.590 to 1.620; (2) a refractive index in a folding portion direction is from 1.670 to 1.700; (3) a refractive index in a thickness direction is 1.520 or less; and (4) a density is 1.380 g/cm3 or more, wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

Abstract: Provided is a foldable display excellent in mass productivity, and free of a risk of causing distortion in an image displayed at a folding portion thereof after being repeatedly folded. The foldable display includes at least: a surface protective film; a polarizer; and a retardation layer, wherein the surface protective film is a polyester film satisfying the following conditions and having a thickness of from 10 ?m to 80 (1) a refractive index in a bending direction is from 1.590 to 1.620; (2) a refractive index in a folding portion direction is from 1.670 to 1.700; (3) a refractive index in a thickness direction is 1.520 or less; and (4) a density is 1.380 g/cm3 or more, wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

Abstract: The present invention provides a polarizing plate for a foldable display free of a risk of causing distortion in an image displayed at a folding portion thereof after being repeatedly folded. The polarizing plate for a foldable display includes: a polarizer; and a polarizer protective film formed of a polyester film laminated on at least one surface of the polarizer, wherein the polyester film satisfies the following conditions: (1) a refractive index in a bending direction is from 1.590 to 1.620; (2) a refractive index in a folding portion direction is from 1.670 to 1.700; (3) a refractive index in a thickness direction is 1.520 or less; and (4) a density is 1.380 g/cm3 or more, wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

Abstract: Provided is a polyester film for a touchscreen module substrate of a foldable display which is free of occurrence of a crack at a folding portion thereof, in order to provide a foldable display excellent in mass productivity, and free of a risk of causing distortion in an image displayed at a folding portion thereof after being repeatedly folded. The polyester film for a touchscreen module substrate of a foldable display satisfies the following conditions: (1) a refractive index in a bending direction is from 1.590 to 1.620; (2) a refractive index in a folding portion direction is from 1.670 to 1.700; (3) a refractive index in a thickness direction is 1.520 or less; and (4) a density is 1.380 g/cm or more, wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

Abstract: Provided is a laminated film for a foldable display, the laminated film being free of occurrence of a fold mark or a crack at a folding portion thereof, in order to provide, for example, a foldable display excellent in mass productivity, and free of a risk of causing distortion in an image displayed at a folding portion thereof after being repeatedly folded. The laminated film for a foldable display includes: a polyester film having a thickness of from 10 ?m to 100 ?m; and an adhesive layer formed on at least one surface of the polyester film, wherein the polyester film satisfies the following conditions: (1) a refractive index in a bending direction is from 1.590 to 1.620; (2) a refractive index in a folding portion direction is from 1.670 to 1.700; (3) a refractive index in a thickness direction is 1.520 or less; and (4) a density is 1.380 g/cm3 or more, wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

Abstract: Provided is a foldable display that is excellent in mass production applicability and unlikely to have image distortion at the folding portion of the display after repeated folding, as well as a mobile device equipped therewith. The foldable display contains a surface protection film and a polarizer. The surface protection film is composed of a polyester film, and the angle made by the slow axis of the polyester film with the absorption axis of the polarizer is 10 to 80°. The polyester film has a refractive index in the bending direction of 1.590 to 1.620, a refractive index in the direction of a folding portion of 1.670 to 1.700, a refractive index in the thickness direction of 1.520 or less, and a density of 1.380 g/cm3 or more, wherein the bending direction refers to a direction orthogonal to the folding portion of the polyester film to be folded.

Abstract: Provided is a polyester film for foldable displays that is unlikely to have cracks in the folding portion with the aim of providing a foldable display that is excellent in mass production applicability, and that does not have image distortion that may appear in the folding portion after the display is repeatedly folded. The polyester film has a thickness of 10 to 80 ?m, a refractive index in the bending direction of 1.590 to 1.620, a refractive index in the direction of a folding portion of 1.670 to 1.700, a refractive index in the thickness direction of 1.520 or less, and a density of 1.380 g/cm3 or more, wherein the bending direction refers to a direction orthogonal to the folding portion of the polyester film to be folded.

Abstract: Provided are a foldable display that is excellent in mass production applicability, and that does not have image distortion that can appear in the folding portion after the display is repeatedly folded; and a mobile device equipped with such a foldable display. Provided are a polyester film for surface protection films and a hard coating film for surface protection films for the foldable display and mobile device. The polyester film is for foldable display surface protection films, wherein the polyester film is cut in sheet form, the polyester film has a thickness of 10 to 75 ?m, the polyester film has an intrinsic viscosity of 0.55 to 0.65 dl/g, and the amount of rise of a cut plane on at least one side of one or more cut end portions is 35 ?m or less. The hard coating film, the foldable display, and the mobile device use the polyester film for foldable display surface protection films.