Patent ID: 7401477

Claim:
A method of bending a glass sheet which has been heated to have a viscosity of not lower than 10 5 Pa·s and not higher than 10 8 Pa·s, comprising the steps of: bending the glass sheet by pressing portions of the heated glass sheet having a viscosity of not lower than 10 5 Pa·s and not higher than 10 8 Pa·s against a bending surface, wherein the portions of the heated glass sheet having a viscosity of not lower than 10 5 Pa·s and not higher than 10 8 Pa·s are pressed against the bending surface in the bending step; and controlling a bending temperature T and a bending time period t for the glass sheet so as to satisfy the following formulas 1 and 2: 0.05<φ<2.00 Formula 1 ϕ = ∫ 0 t ⁢ P ⁡ ( τ ) η ⁡ ( T ) ⁢ ⅆ τ Formula ⁢ ⁢ 2 where P(τ) is a surface pressure difference (unit: Pa) between a pressure applied on a primary surface of the glass sheet and a pressure applied on a rear surface of the glass sheet at a time τ, t is a bending time period (unit: s), η(T) is the viscosity (unit: Pa·s) of the glass sheet at a temperature T, and T is a bending temperature (unit: ° C.) at a time τ.