Authors:
Kazumasa Tatsumi
1
;
2
;
Kentaro Saeki
1
;
Shin Kubota
1
;
Yoshikatsu Kaneda
1
;
Kenji Uno
3
;
1
;
Kazuhiko Ohnuma
1
;
3
and
Tatsuo Shiina
2
Affiliations:
1
SEED CO., LTD, 2-40-2 Hongo, Bunkyo-ku, Tokyo, 369-0131, Japan
;
2
Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba-shi, Chiba, 263-8522, Japan
;
3
Laboratorio de Lente Verde, 98-1 Nozomino, Sodegaura, Chiba, 299-0251, Japan
Keyword(s):
Wavefront Sensor, Wavefront Shape, Contact Lenses, Resin, Mold.
Abstract:
Advances in molding technology have made it possible to produce plastic molded products with complex shapes. In contact lens manufacturing, a double-sided molding method using resin molds is employed, where the front and back designs are replicated through injection molding. However, shape changes in the resin molds caused by heat treatment (polymerization) during the manufacturing process affect lens characteristics. This study proposes a method using optical techniques to clarify the influence of mold design and polymerization on resin mold shapes. Five types of resin molds were measured using a wavefront sensor, which allows for high-accuracy, non-contact measurement. Wavefront aberrations and radii of curvature were evaluated, and results showed that polymerization caused slight deviations from the design values and changes in shrinkage rates. This method demonstrated its effectiveness in measuring and evaluating resin molds for contact lens production. Furthermore, the proposed
method has wide-ranging applications, including quality control in lens manufacturing and evaluating the transfer accuracy of metal molds.
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