Patent ID: 6334335
Filing Date: 2002-01-01
Classification: B29C,C03B,Y02P

Abstract:
A method of precisely manufacturing a glass optical element as a shaped article of glass by press forming a glass material within a mold separable into an tipper and a lower die both of which are opposed to each other with a hollow space left therebetween and which have forming surfaces mirror finished, the method comprising:(a) heating the glass material to a predetermined temperature which corresponds to a viscosity range between 105.5 and 107.6 poises; (b) introducing the glass material at the predetermined temperature into the hollow space formed by the upper and the lower dies preheated to first and second temperatures which are lower than the predetermined temperature, respectively, and which corresponds to viscosity not lower than 109 poises, the first temperature being lower than the second temperature; (c) starting to press form the glass material at a viscosity less than 109 poises within the upper and the lower dies kept at the first and the second temperatures different from each other, and forcibly cooling the upper and the lower dies simultaneously with the start of the press forming or during the press forming so as to cause a difference of adhesion to occur between the glass material and each of the upper and the lower dies; and (d) releasing the mold to take out the glass optical element with the upper and the lower dies kept at temperatures different from each other.