A method of manufacturing a glass sheet includes a start point forming step of forming a scribe line on a preset cutting portion of a glass sheet, a setting step of causing, through use of a support member having a groove-shaped recess, the support member to support the glass sheet having the scribe line formed thereon from one surface side so that the preset cutting portion is arranged on the recess, and a cutting step of generating a negative pressure in the recess to bend the preset cutting portion on the recess so that the one surface side protrudes, to thereby cut the glass sheet along the preset cutting portion with the scribe line as the start point. At the time of performing the cutting step, the entire recess is covered with a cover member from another surface side of the glass sheet through intermediation of the glass sheet.

A method of manufacturing a glass sheet includes a start point forming step of forming a scribe line on a preset cutting portion of a glass sheet, a setting step of causing, through use of a support member having a groove-shaped recess, the support member to support the glass sheet having the scribe line formed thereon from one surface side so that the preset cutting portion is arranged on the recess, and a cutting step of generating a negative pressure in the recess to bend the preset cutting portion on the recess so that the one surface side protrudes, to thereby cut the glass sheet along the preset cutting portion with the scribe line as the start point. At the time of performing the cutting step, the entire recess is covered with a cover member from another surface side of the glass sheet through intermediation of the glass sheet.

A glass plate bend-breaking machine for a glass plate includes a supporting mechanism by which a glass plate with a predetermined bend-breaking line as a cut line formed on an upper surface, i.e., one surface, thereof is supported at a lower surface, i.e., another surface, of the glass plate; and press-breaking devices and for press-breaking the glass plate along the predetermined bend-breaking line. Each of the press-breaking devices has a pressing body for simultaneously pressing a plurality of parts and along the predetermined bend-breaking line on the upper surface of the glass plate at the time of press-breaking the glass plate along the predetermined bend-breaking line at each of press-breaking positions on the glass plate.

A method for separating a portion from a sheet glass element having a thickness of at least 2 millimeters along an intended separation line that divides the sheet glass element into the portion and a remaining main part is provided. The method includes producing filamentary damages comprising sub-micrometer hollow channels in a volume of the glass sheet element adjacently aligned along the separation line; and heating and/or cooling the glass sheet element to cause expansion and/or contraction so that the portion detaches from the main part along the separation line. The portion and the remaining main part each remain intact as a whole. The step of producing the filamentary damages includes generating a plasma within the volume with laser pulses of an ultrashort pulse laser; and displacing points of incidence of the laser pulses over a surface of the glass sheet element along the separation line.

A method for separating a portion from a sheet glass element having a thickness of at least 2 millimeters along an intended separation line that divides the sheet glass element into the portion and a remaining main part is provided. The method includes producing filamentary damages comprising sub-micrometer hollow channels in a volume of the glass sheet element adjacently aligned along the separation line; and heating and/or cooling the glass sheet element to cause expansion and/or contraction so that the portion detaches from the main part along the separation line. The portion and the remaining main part each remain intact as a whole. The step of producing the filamentary damages includes generating a plasma within the volume with laser pulses of an ultrashort pulse laser; and displacing points of incidence of the laser pulses over a surface of the glass sheet element along the separation line.

A method of manufacturing a glass sheet includes: an initial crack forming step of forming an initial crack on a mother glass sheet (MG); and a cleaving step of causing a crack (CR) to propagate in a direction along a preset cleaving line (CL) and in a thickness direction of the mother glass sheet (MG), the crack starting from the initial crack, through use of a thermal stress generated by heating of an irradiation region (SP) of laser light (L) and cooling of a cooling region (CP). The cleaving step includes heating a surface layer (SL) and an inner portion (IL) of the mother glass sheet (MG) with the laser light (L) in the irradiation region (SP) and setting a difference ΔT between a highest temperature in the irradiation region (SP) and a lowest temperature in the cooling region to 575° C. or more.

This method includes a laser irradiation step of radiating, in at least a part of a preset cleaving line (CL) of a mother glass sheet (MG), laser light (L) to a position (OSP) separated from the preset cleaving line (CL) so that a crack (CR2) propagates along the preset cleaving line (CL).

A method for processing a transparent workpiece includes forming a contour of defect in the transparent workpiece and separating the transparent workpiece along the contour using an infrared laser beam. During separation, the method also includes detecting a position and propagation direction of a crack tip relative to a reference location and propagation direction of an infrared beam spot, determining a detected distance and angular offset between the crack tip and the reference location of the infrared beam spot, comparing the detected distance to a preset distance, comparing the detected angular offset to a preset angular offset, and modifying at least one of a power of the infrared laser beam or a speed of relative translation between the infrared laser beam and the transparent workpiece in response to a difference between the detected distance and the preset distance and between the detected angular offset and the preset angular offset.

A method for producing an intermediate glass plate includes a defect formation step, a separation step, and a polishing step. In the defect formation step, a defect is formed on main surfaces of glass blanks by irradiating a laminate of the glass blanks with a laser beam from one side in a lamination direction in which the glass blanks are laminated, along the lamination direction, and moving the laser beam relative to the laminate such that a circle is drawn in a view from the main surfaces of the glass blanks. In the separation step, a cylindrical laminate is formed by separating a removal target portion along the defect while maintaining the laminate. In the polishing step, a side wall surface of the laminate is polished while maintaining the cylindrical laminate so as to obtain a disk-shaped intermediate glass plate that has been subjected to edge surface polishing.

A glass and an enclosure, including windows, cover plates, and substrates for mobile electronic devices comprising the glass. The glass has a crack initiation threshold that is sufficient to withstand direct impact, has a retained strength following abrasion that is greater than soda lime and alkali aluminosilicate glasses, and is resistant to damage when scratched. The enclosure includes cover plates, windows, screens, and casings for mobile electronic devices and information terminal devices.