| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To shorten the time for a cooling step after a thermal treatment step and suppress the production of a large amount of goods-in-process before the thermal treatment step, in the thermal treatment step to reduce the refraction index distribution of a glass molded lens after molding. <P>SOLUTION: An optical molded article W is conveyed in a heating apparatus 100. The optical molded article W is heated to a certain temperature at which the glass viscosity becomes≥10<SP POS="POST">13</SP>dPa s and≤10<SP POS="POST">14.5</SP>dPa s. Then, the optical molded article W is released outside the heating apparatus 100. Thereby, the optical molded article W is cooled to a temperature at which the glass viscosity becomes 10<SP POS="POST">20</SP>dPa s, at a cooling rate of≥50°C/min and≤400°C/min. The axisymmetrical temperature difference to the optical axis of the optical molded article W in the cooling step is made to be≥1°C and≤5°C. In order to accomplish this, the conductance of the thermal flow outgoing from the optical molded article W in the cooling step is axisymmetric with respect to the optical axis of the optical molded article W. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
