A strengthened glass sheet product along with a process and an apparatus for strengthening a glass sheet are provided. The process comprises cooling the glass sheet by non-contact thermal conduction for sufficiently long to fix a surface compression and central tension of the sheet. The process results in thermally strengthened glass sheets having improved breakage properties.

A strengthened glass sheet product along with a process and an apparatus for strengthening a glass sheet are provided. The process comprises cooling the glass sheet by non-contact thermal conduction for sufficiently long to fix a surface compression and central tension of the sheet. The process results in thermally strengthened glass sheets having improved breakage properties.

To provide a tempered glass sheet having a thickness of from 1.8 to less than 2.5 mm, which is capable of satisfying the fragmentation quality and impact strength quality required for windowpanes for automobiles. A tempered glass sheet having a first surface, a second surface opposed to the first surface and a side surface connecting the first and second surfaces, and having a thickness of from 1.8 to less than 2.5 mm, wherein at the first surface, the average value of the surface compressive stress is within a range of from 100 to 160 MPa, and the average value of the surface strength is within a range of from 220 to 400 MPa.

There is provided a tempered glass plate, wherein a thickness of the tempered glass plate is less than or equal to 2.7 mm, wherein on a surface of the tempered glass plate, a plurality of stress marks are formed, wherein a distance between closest stress marks of the plurality of stress marks is less than or equal to 20 mm, wherein the surface of the tempered glass plate includes a first virtual circle that is formed by connecting points that are separated from a center of one of the plurality of stress marks by 2.5 mm, wherein the tempered glass plate includes a non elastic-wave region that is not affected by an elastic-wave generated during fracturing, and wherein, in the non elastic-wave region, an average number of cracks that exist in the first virtual circle is greater than or equal to 3.4.

There is provided a tempered glass plate, wherein a thickness of the tempered glass plate is less than or equal to 2.7 mm, wherein on a surface of the tempered glass plate, a plurality of stress marks are formed, wherein a distance between closest stress marks of the plurality of stress marks is less than or equal to 20 mm, wherein the surface of the tempered glass plate includes a first virtual circle that is formed by connecting points that are separated from a center of one of the plurality of stress marks by 2.5 mm, wherein the tempered glass plate includes a non elastic-wave region that is not affected by an elastic-wave generated during fracturing, and wherein, in the non elastic-wave region, an average number of cracks that exist in the first virtual circle is greater than or equal to 3.4.

A strengthened glass sheet product as well as process and an apparatus for making the product. The process comprises cooling the glass sheet by non-contact thermal conduction for sufficiently long to fix a surface compression and central tension of the sheet. The process results in thermally strengthened glass sheets having improved breakage properties.

A strengthened glass sheet product as well as process and an apparatus for making the product. The process comprises cooling the glass sheet by non-contact thermal conduction for sufficiently long to fix a surface compression and central tension of the sheet. The process results in thermally strengthened glass sheets having improved breakage properties.

A strengthened glass sheet product along with a process and an apparatus for strengthening a glass sheet are provided. The process comprises cooling the glass sheet by non-contact thermal conduction for sufficiently long to fix a surface compression and central tension of the sheet. The process results in thermally strengthened glass sheets having improved breakage properties.

A strengthened glass sheet product along with a process and an apparatus for strengthening a glass sheet are provided. The process comprises cooling the glass sheet by non-contact thermal conduction for sufficiently long to fix a surface compression and central tension of the sheet. The process results in thermally strengthened glass sheets having improved breakage properties.

There is provided a tempered glass plate, wherein a thickness of the tempered glass plate is less than or equal to 2.7 mm, wherein on a surface of the tempered glass plate, a plurality of stress marks are formed, wherein a distance between closest stress marks of the plurality of stress marks is less than or equal to 20 mm, wherein the surface of the tempered glass plate includes a first virtual circle that is formed by connecting points that are separated from a center of one of the plurality of stress marks by 2.5 mm, wherein the tempered glass plate includes a non elastic-wave region that is not affected by an elastic-wave generated during fracturing, and wherein, in the non elastic-wave region, an average number of cracks that exist in the first virtual circle is greater than or equal to 3.4.