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http://dx.doi.org/10.3795/KSME-A.2013.37.1.039

Development of Plastic Lenses for High-Resolution Phone Camera by Injection-Compression Molding  

Lee, Ho Sang (Dept. of Aeronautical & Mechanical Design Engineering, Korea Nat'l Univ. of Transportation)
Jeon, Won Taek (N2A Co., Ltd.)
Kim, Sung Woo (N2A Co., Ltd.)
Publication Information
Transactions of the Korean Society of Mechanical Engineers A / v.37, no.1, 2013 , pp. 39-46 More about this Journal
Abstract
This study aims to develop a plastic aspheric lens for a 13-megapixel mobile phone camera by injection-compression molding. A mold for injection-compression molding experiments was fabricated with a movable upper plate and four springs. During cavity filling for an aspheric lens with a thickness ratio of 2, a weldline was formed under conventional injection molding, whereas no weldline was formed under injection-compression molding with a compression stroke of 0.3 mm. The flow patterns were in good agreement with the simulation results. The birefringence decreased as the compression stroke increased, and the birefringence produced by injection-compression molding was very low and more uniform compared with that produced by injection molding. In addition, the bulk birefringence of an assembly composed of four plastic lenses was significantly affected by the orientation of the lenses to be mounted.
Keywords
Lens; Weldline; Phase Difference; Birefringence; Injection Molding; Injection-Compression Molding; Mold;
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