Press molding method for an optical element and apparatus therefor
US5188650A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 16, 1991 |
| Grant date | Feb 23, 1993 |
| Priority date | — |
| Expiry date | Dec 16, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S425/808
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Molding is effected while pressing pressure is continuously or stepwise controlled so that at the initial stage in which the temperature distribution of a glass blank is not sufficiently uniformized, molding may be effected with relatively low pressing pessure and in a state in which the whole of the glass blank is uniformly increased in temperature, press molding may be effected with the pressing pressure increased. In a press molding apparatus for an optical element, during press molding, the glass blank is press-molded while the pressing pressure is continuously or stepwise varied so that at a temperature whereat the glass viscosity of the glass blank corresponds to 10.sup.21 -10.sup.11 poise, molding may be started with pressing pressure of 10 kg/cm.sup.2 -100 kg/cm.sup.2, and thereafter in a temperature range in which the glass viscosity x of the central portion of the glass blank corresponds to 10.sup.11 -10.sup.10 poise, pressing pressure in the range of 10.times.(10.sup.11-x)-100+10.times.(10.sup.11-x) kg/cm.sup.2 may be applied, and further at a temperature whereat the glass viscosity corresponds to 10.sup.10 or less, pressing pressure of 100 kg/cm.sup.2 or greater may be …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.