Search | Korea Science

Lee Ho Cheol;Yang Min Yang
- Transactions of the Korean Society of Machine Tool Engineers
- /
- v.14 no.2
- /
- pp.14-20
- /
- 2005
This paper describes a dwell time calculation algorithm for polishing tool path generation in the small toot polishing process of the axis-symmetrical lens. Generally dwell time control in the polishing machines means that small polishing tool stays for a dwell time at the specific surface position to get the expected polishing depth. Polishing depth distribution on an aspherical lens surface consists of the superposition of the local polishing depth at the each dwell position. Therefore, tool path generation needs each dwell time together with tool positioning data during the polishing tool movements on the aspherical lens surface. The linear algebraic equation of removal depth removal matrix and dwell time is formulated. Parametric effects such as the dwell d interval are simulated to validate the dwell time calculation algorithm.
PDF KSCI

Cha, Du-Hwan;Hwang, Yeon;Kim, Jeong-Ho;Kim, Hye-Jeong
- Journal of the Optical Society of Korea
- /
- v.13 no.2
- /
- pp.213-217
- /
- 2009
The transcription characteristics of the mold surface in the molding of aspherical 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. For the form topography, the molded lens showed a transcription ratio of 93.4% against the mold, which is obtained by comparing the form error (PV) values of the mold and the molded lens. The transcription characteristics of the roughness topography were ascertained by bearing ratio analysis.
https://doi.org/10.3807/JOSK.2009.13.2.213 인용 PDF KSCI

Yang, In-Young;Kim, Seung-Hoon
- Journal of the Korean Society for Nondestructive Testing
- /
- v.25 no.2
- /
- pp.127-132
- /
- 2005
The optical glass lens is required high dimensional precision such as the lack of defect. In this paper, we examined the detectable defect by using the resonant ultrasound spectroscopy(RUS). The RUS is the measurement system which is to excite the specimen and to inspect the differences of resonant frequency pattern between acceptable specimen and specimen which has some defects. In this paper, for nondestructive evaluation by using RUS, we measured the resonant frequency of each specimen which is spherical and aspherical glass lens. With the results, we knew the polishing processing degree of spherical glass lens by the measured resonant frequency and could evaluate the characteristic of aspherical glass lens about some flaws.
PDF KSCI

Yi I.L.;Park S.J.;Lee G.B.;Lee S.W.;Yu Y.G.;Kwak B.M.;Baek S.Y.
- Proceedings of the Korean Society of Precision Engineering Conference
- /
- 2005.10a
- /
- pp.851-856
- /
- 2005
The precision fabrication of aspherical lenses is increasingly required for the latest applications of compact and high resolution video-recording or camera systems. Micro-optical components, including micro-spherical or aspherical lenses and reflecting mirrors, are generally required to be manufactured with high shape accuracy, extremely low surface roughness and no surface damage. To meet the needs of the precision fabrication system, a bed which supports the micro aspherical lens fabrication machines stably and safely is required. In this study, the thickness of the ribs of the bed is optimized using the CAD integrated optimal design system, a virtual DS program.
PDF

Kim H.T.;Yang H.J.
- Proceedings of the Korean Society of Precision Engineering Conference
- /
- 2005.06a
- /
- pp.100-103
- /
- 2005
In this study, tool path control algorithm for aspherical surface grinding was derived and discussed. The aspherical surface actually means contact points between lens and tool. Tool positions are generally defined at the center of a tool, so there is difference between tool path and lens surface. The path was obtained from contact angle and relative position from the contact point. The angle could be calculated after differentiating an aspheric equation and complex algebraic operations. The assumption of the control algorithm was that x moves by constant velocity while z velocity varies. X was normal to the radial direction of lens, but z was tangential. The z velocities and accelerations were determined from current error and next position in each step. In the experiment, accuracy of the control algorithm was checked on a micro-precision machine. The result showed that the control error tended to be diminished when the tool diameter increased, and the error was under sub-micro level.
PDF