Glass sheet cutting method

1. A glass sheet cutting method, comprising:

radiating a laser beam from above along a preset cutting line of a glass sheet; and

fusing and dividing the glass sheet using the preset cutting line as a boundary,

wherein the laser beam comprises:

a fusing laser beam for fusing the glass sheet; and

an annealing laser beam for annealing fused end surfaces of the glass sheet,

wherein a jet nozzle for jetting assist gas to blow off molten foreign matter generated by the fusing is provided,

wherein the glass sheet is fused and divided into a product portion and a non-product portion by the fusing laser beam,

wherein the assist gas is jetted onto a region irradiated with the fusing laser beam from above on a product portion side, and

wherein the annealing laser beam is obliquely radiated from above onto at least one of the fused end surfaces of the product portion through a gap that is formed between the fused end surfaces by the fusing.

2. The glass sheet cutting method according to claim 1 , wherein a region irradiated with the annealing laser beam has an intensity distribution in which an intensity of thermal energy changes from a fusing execution portion to a fusing completed portion on the preset cutting line.

3. The glass sheet cutting method according to claim 2 , wherein the annealing laser beam is inclined so as to come closer to the glass sheet from a fusing uncompleted portion side toward a fusing completed portion side on the preset cutting line or from the fusing completed portion side toward the fusing uncompleted portion side on the preset cutting line.

4. The glass sheet cutting method according to claim 3 , wherein the annealing laser beam has an elliptical beam shape in cross-section orthogonal to an optical axis thereof.

5. The glass sheet cutting method according to claim 2 , wherein the annealing laser beam has an elliptical beam shape in cross-section orthogonal to an optical axis thereof.

6. The glass sheet cutting method according to claim 2 , wherein the region irradiated with the annealing laser beam is formed to overlap the region irradiated with the fusing laser beam so as to extend astride the region irradiated with the fusing laser beam.

7. The glass sheet cutting method according to claim 1 , wherein the annealing laser beam is inclined so as to come closer to the glass sheet from a fusing uncompleted portion side toward a fusing completed portion side on the preset cutting line or from the fusing completed portion side toward the fusing uncompleted portion side on the preset cutting line.

8. The glass sheet cutting method according to claim 7 , wherein the annealing laser beam has an elliptical beam shape in cross-section orthogonal to an optical axis thereof.

9. The glass sheet cutting method according to claim 7 , wherein the region irradiated with the annealing laser beam is formed to overlap the region irradiated with the fusing laser beam so as to extend astride the region irradiated with the fusing laser beam.

10. The glass sheet cutting method according to claim 1 , wherein the annealing laser beam has an elliptical beam shape in cross-section orthogonal to an optical axis thereof.

11. The glass sheet cutting method according to claim 1 , wherein the region irradiated with the annealing laser beam is formed to overlap the region irradiated with the fusing laser beam so as to extend astride the region irradiated with the fusing laser beam.

12. The glass sheet cutting method according to claim 1 , wherein the fusing laser beam and the annealing laser beam are formed through splitting a laser beam emitted from a single light source.

13. The glass sheet cutting method according to claim 1 , wherein the fusing laser beam and the annealing laser beam are formed through emission from separate light sources.

14. A glass sheet cutting method, comprising:

radiating a fusing laser beam and an annealing laser beam along a preset cutting line of a glass sheet; and

fusing and dividing the glass sheet using the preset cutting line as a boundary,

wherein a region irradiated with the annealing laser beam is set larger in dimension in a fusing propagating direction along the preset cutting line than a region irradiated with the fusing laser beam,

wherein the region irradiated with the annealing laser beam overlaps the region irradiated with the fusing laser beam so as to extend astride the region irradiated with the fusing laser beam along the fusing propagating direction, and

wherein the region irradiated with the fusing laser beam overlaps the region irradiated with the annealing laser beam on a front side in the fusing propagating direction with respect to a center position of the region irradiated with the annealing laser beam in the fusing propagating direction.

15. The glass sheet cutting method according to claim 14 ,

wherein the glass sheet is fused and divided into a product portion and a non-product portion, and

wherein a larger part of the region irradiated with the annealing laser beam is formed on a product portion side than on a non-product portion side.

16. The glass sheet cutting method according to claim 14 , wherein the region irradiated with the annealing laser beam has an elongated shape along the fusing propagating direction.

17. The glass sheet cutting method according to claim 16 , wherein the annealing laser beam is obliquely radiated onto a surface of the glass sheet.

18. The glass sheet cutting method according to claim 14 , wherein the fusing laser beam and the annealing laser beam have different wavelengths.

19. The glass sheet cutting method according to claim 18 , wherein the fusing laser beam and the annealing laser beam comprise laser beams oscillated by different oscillators.