• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.10a
• /
• pp.289-292
• /
• 2007

To prevent the damage of glass lens molds and deterioration of glass lenses using in progressive GMP process, a thermal stress and a deformation of the glass lens molds at forming temperature should be considered in the design step. In this study, as a fundamental study to develop a multi cavity mold used in an aspheric glass lens molding, a heat transfer and a thermal stress analysis were carried out for the case of one cavity glass lens mold used in progressive GMP process. Finally, using analysis results, we estimated the thermal stress in a glass lens mold and predicted a modified height of guide ring that determines the forming height of a glass lens.

• Journal of Korea Society of Industrial Information Systems
• /
• v.12 no.3
• /
• pp.124-131
• /
• 2007

Aspheric glass lenses was fabricated by glass molding press(GMP), which is a plano-aspheric convox shape and intended for use as an optical design of 3 megapixel and 2.5 magnifications zoom in a camera phone module. Transcription ratio of form accuracy (PV) as well as resolution properties was measured for evaluation the molded lens. Form accuracy (PV) of the mold surface was $0.127\;{\mu}m$ in an aspheric and $0.168\;{\mu}m$ in a plano, in case of the molded lens it shows $0.205\;{\mu}m$ and $0.223\;{\mu}m$, respectively. Resolution of the molded lens was measured as a MTF[Contrast]. The molded lens shows contrast of 32.9% at 80 1p/mm and the value is similar with contrast of 33% obtained simulation.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.217-218
• /
• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.06a
• /
• pp.193-194
• /
• 2009

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2008.10a
• /
• pp.363-366
• /
• 2008

The transcription characteristics in the molding of aspheric glass lenses for camera phone modules have been investigated experimentally. The surface topographies of both the form and the roughness were compared between the mold and the molded lens. The molded lens showed a transcription ratio of 93.4%, which is obtained by comparing the form accuracy (PV) values of the mold and the molded lens. The transcription of the roughness topography was ascertained by bearing ratio analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.336-336
• /
• 2008

The transcription characteristics in the molding of aspheric glass lenses for camera phone modules have been investigated experimentally. The surface topographies of both the form and the roughness were compared between the mold and the molded lens. The molded lens showed a transcription ratio of 93.4%, which is obtained bycomparing the form accuracy (PV) values of the mold and the molded lens. The transcription of the roughness topography was ascertained by bearing ratio analysis.

• Journal of the Optical Society of Korea
• /
• v.11 no.3
• /
• pp.85-92
• /
• 2007

In the past, precision optical glass lenses were produced through multiple processes such as grinding and polishing, but mass production of aspheric glass lenses requiring high accuracy and having complex profile was rather difficult. In such a background, the high-precision optical glass molding pressing (GMP) process was developed with an eye to mass production of precision optical glass parts by molding press. In this paper, as a fundamental research to develop the multi-cavity mold for higher productivity of a progressive GMP process used in the fabrication of an aspheric glass lens, an aspheric glass lens forming simulation was carried out.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.469-470
• /
• 2006

The purpose of this research was to investigate and to find out the optimal annealing condition to mold an aspheric glass to be used for mobile phone module having 2 megapixel and $2.5{\times}$ zoom. Taking annealing rate and re-press temperature after molding as molding variables under the identical molding temperature and pressure, a glass lens was molded. And, Form Accuracy, Lens Thickness, Refractive Index, and Modulation Transfer Function(MTF) were measured in order to observe characteristics of molded lens, and then optimal annealing conditions were determined based on the resulting data. Properties of lens molded under the optimal conditions revealed Form Accuracy[PV] $0.2047\;{\mu}m$ in aspheric surface, and $0.2229\;{\mu}m$ in plane, and MTF value was 30.3 % under 80 lp/mm.

• Transactions on Electrical and Electronic Materials
• /
• v.9 no.6
• /
• pp.237-242
• /
• 2008

The effects of the process parameters in the molding of aspheric glass lenses for camera phone modules have been investigated experimentally. The molding conditions were optimized with respect to the form accuracy (PV) (the response variable) of the molded lens. The experimental conditions were obtained by employing a factorial design method. From the analysis of variance (ANOVA) and P-value (significance level), the slow cooling rate was found to affect the response variable most significantly. The lens molded under the optimum molding condition showed a transcription ratio of 93.4%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.464-464
• /
• 2008

This study investigated the slow cooling conditions in the molding of aspheric glass lens using the design of experiment (DOE). The optimization of the slow cooling conditions with respect to the form accuracy (PV) of the molded lens were ascertained by employing full factorial design. As a result of the analysis of variance (ANOVA) and P-value (significance level), it was verified that slow cooling rate represent the most significant operative variables that affect the corresponding response variable. In the optimum condition, the molded lens show 82% of transcription ratio.