A foldable glass substrate includes a top surface, a bottom surface, and a side surface. The side surface includes a first side surface extending at a first angle from the top surface, a second side surface extending at a second angle from the bottom surface, and a third side surface extending from each of the first side surface and the second side surface. A length of the third side surface in a direction substantially perpendicular to at least one of the top surface and the bottom surface is equal to or greater than about 0.3 times and equal to or less than about 0.7 times of a minimum distance between the top surface and the bottom surface. The minimum distance is equal to or greater than about 15 micrometers (μm) and equal to or less than about 100 μm.

A foldable glass substrate includes a top surface, a bottom surface, and a side surface. The side surface includes a first side surface extending at a first angle from the top surface, a second side surface extending at a second angle from the bottom surface, and a third side surface extending from each of the first side surface and the second side surface. A length of the third side surface in a direction substantially perpendicular to at least one of the top surface and the bottom surface is equal to or greater than about 0.3 times and equal to or less than about 0.7 times of a minimum distance between the top surface and the bottom surface. The minimum distance is equal to or greater than about 15 micrometers (μm) and equal to or less than about 100 μm.

A foldable glass substrate includes a top surface, a bottom surface, and a side surface. The side surface includes a first side surface extending at a first angle from the top surface, a second side surface extending at a second angle from the bottom surface, and a third side surface extending from each of the first side surface and the second side surface. A length of the third side surface in a direction substantially perpendicular to at least one of the top surface and the bottom surface is equal to or greater than about 0.3 times and equal to or less than about 0.7 times of a minimum distance between the top surface and the bottom surface. The minimum distance is equal to or greater than about 15 micrometers (μm) and equal to or less than about 100 μm.

An alkali-free glass of the present invention includes as a glass composition, in terms of mass %, 55% to 70% of SiO.sub.2, 15% to 25% of Al.sub.2O.sub.3, 0% to 5% of B.sub.2O.sub.3, 3% to 10% of MgO, 7% to 20% of SrO, and 0% to 5% of BaO, is substantially free of an alkali metal oxide, and has a strain point of more than 720° C.

Apparatus and method for treating a substrate, for example texturing a substrate. In some embodiments, a masking material is applied to a surface of the substrate in a predetermined pattern, the surface thereafter contacted with an etchant that removes the masking material. Contacting the surface with the etchant produces multiple co-located textures. In other embodiments, the masking step can be eliminated, and the etchant is applied in a predetermined pattern to produce multiple co-located textures. In still other embodiments, the substrate has a chemical composition, and the substrate is exposed to a leachant that leaches at least one constituent of the chemical composition to produce a substrate with a varying chemical composition at the substrate surface.

Apparatus and method for treating a substrate, for example texturing a substrate. In some embodiments, a masking material is applied to a surface of the substrate in a predetermined pattern, the surface thereafter contacted with an etchant that removes the masking material. Contacting the surface with the etchant produces multiple co-located textures. In other embodiments, the masking step can be eliminated, and the etchant is applied in a predetermined pattern to produce multiple co-located textures. In still other embodiments, the substrate has a chemical composition, and the substrate is exposed to a leachant that leaches at least one constituent of the chemical composition to produce a substrate with a varying chemical composition at the substrate surface.

A manufacturing method of a glass plate having holes, includes: (1) having a first surface of a glass base material irradiated with a laser, to form initial holes each having a first initial opening, wherein each initial hole is an initial through hole or non-through hole, wherein the first initial opening has a maximum dimension φ.sub.1S of 5 μm or greater, and wherein in each initial hole, denoting a depth as d.sub.1, an aspect ratio (d.sub.1/φ.sub.1S) is 15 or greater; and (2) etching the glass base material with an alkaline solution, to form processed holes from the initial holes, wherein each processed hole has a first opening on the first surface, and wherein the first opening has a diameter φ.sub.1 defined as an average of diameters of circumscribed and inscribed circles of the first opening, and a roundness P.sub.1, and a ratio P.sub.1/φ.sub.1 is 10% or less.

A manufacturing method of a glass plate having holes, includes: (1) having a first surface of a glass base material irradiated with a laser, to form initial holes each having a first initial opening, wherein each initial hole is an initial through hole or non-through hole, wherein the first initial opening has a maximum dimension φ.sub.1S of 5 μm or greater, and wherein in each initial hole, denoting a depth as d.sub.1, an aspect ratio (d.sub.1/φ.sub.1S) is 15 or greater; and (2) etching the glass base material with an alkaline solution, to form processed holes from the initial holes, wherein each processed hole has a first opening on the first surface, and wherein the first opening has a diameter φ.sub.1 defined as an average of diameters of circumscribed and inscribed circles of the first opening, and a roundness P.sub.1, and a ratio P.sub.1/φ.sub.1 is 10% or less.

A heating device, used for heating an aerosol generating substrate to form an aerosol, comprises a heating body, wherein the heating body comprises a base body configured to have a chamber for receiving at least part of the aerosol generating substrate and further comprises an infrared radiation coating formed on the outer surface of the chamber and used for generating infrared rays after a temperature rise and transmitting energy to the aerosol generating substrate in the chamber at least in an infrared radiation manner, so that at least one component in the aerosol generating substrate is volatilized to form an aerosol, wherein the surface roughness of the outer surface of the chamber is greater than the surface roughness of the inner surface of the chamber. A rough surface is formed at an interface between the outer surface of the base body and the infrared electrothermal coating.

A method of manufacturing a window and a window manufactured by the same are provided. A method of manufacturing a window includes laser cutting a base glass into a preliminary window using first laser light, irradiating, with second laser light, a point spaced apart from an edge of the preliminary window at a first distance, and providing a window including a flat portion and an edge portion by wet etching the preliminary window irradiated with the second laser light. A method of manufacturing a window having a chamfer shape at the edge portion is facilitated.