Du-Hwan CHA, Hye-Jeong KIM¹, Hyun-Uk KIM¹, Sang-Suk KIM¹, Yong-Pil PARK², and Jeong-Ho KIM^1*

Department of Material Science and Engineering, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Korea
¹Ultra Precision Optics Team, Korea Photonics Technology Institute (KOPTI), 971-35 Wolchul-dong, Buk-gu, Gwangju 500-460, Korea
²Department of Hospital Biomedical Engineering, Dongshin University, 252 Daeho-dong, Naju, Jeonnam 520-714, Korea

(Received December 25, 2006; Accepted February 27, 2007)

The purpose of this study is to develop aspheric glass lenses 4 mm in diameter by compression molding. The lens is intended for use as an optical design of 3 megapixel and 2.5 magnifications zoom in a camera phone module. Because of the excellent optical performance of glass and aspheric element, which minimize optical aberrations, the adoption of optical designs using of aspheric glass lenses is rapidly increasing with the progress of precision image forming optics. We fabricated the mold using ultra-precision processing of tungsten carbide (WC). The aspheric glass lens was precisely molded and then its characteristics were evaluated. The mechanical and optical properties of the molded lens were investigated and it showed 90–95% transcription ratio and 0.0655λ root-mean-square optical path difference (OPD-rms), which corresponds to a 0.844 Strehl ratio. Based on the optical performance using the Marechal criterion, we supposed that the molded lens is suitable for the optical design. It also means our fabrication process is available.

Key words: aspheric glass lens, ultra-precision grinding, glass molding press (GMP)

^*E-mail address: kimjh@kopti.re.kr