Clean Technology (청정기술)

The Korean Society of Clean Technology (한국청정기술학회)
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Cu Blackening through CuO Oxidation for the Application of Camera Lens Spacers in Mobile Phones

휴대폰 카메라 렌즈 스페이서 적용을 위한 구리의 흑화

  • Lee, Yeji (Department of Chemical Engineering, Pukyong National University) ;
  • Kim, Yong Ha (Department of Chemical Engineering, Pukyong National University) ;
  • Kim, Chang Hyun (Haneul Solution) ;
  • Won, Yong Sun (Department of Chemical Engineering, Pukyong National University)
  • 이예지 (국립부경대학교 화학공학과) ;
  • 김용하 (국립부경대학교 화학공학과) ;
  • 김창현 (한울솔루션) ;
  • 원용선 (국립부경대학교 화학공학과)
  • Received : 2020.12.01
  • Accepted : 2020.12.29
  • Published : 2021.03.31
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Abstract

Black polymer spacers are currently used for physically separating aligned camera lenses in camera modules of mobile phones. However, the mechanical properties of polymer spacers have their limits, especially in the current trend of using more lenses in thinner camera modules. Thus, copper (Cu) becomes a good candidate for those polymer spacers because of its superior mechanical properties and its inherent blackness due to its black surfaced oxides, such as copper (II) oxide (cupric oxide, CuO). The latter property is critical in quality control because the closer the color of a spacer is to black, the less light interference and flaring phenomena can occur. A standard Cu blackening process and its operational conditions were proposed in this study through a comprehensive analysis of previous research and patents. The Cu blackening process is composed of cleaning, deoxidizing, activating, blackening and sealing. The effects of operational parameters, such as the temperature of each unit process and the activator concentration, were then investigated by measuring the blackness of the Cu strips with a colorimeter. The proposed operational conditions were determined by whether the blackness of Cu strips was within the on-spec. value used in the field.

휴대폰의 카메라 모듈 내에 정렬된 카메라 렌즈들은 일반적으로 검은색 폴리머 스페이서(spacer)에 의해서 물리적으로 분리된다. 그러나 카메라 모듈이 계속 얇아지고 삽입되는 렌즈의 수는 계속 증가하는 추세를 고려해볼 때, 렌즈들을 분리해주는 스페이서의 기계적 특성이 점점 중요해지고 있다. 이에 기존 폴리머 스페이서의 대체재로서 우수한 기계적 특성을 가진 구리(Cu) 소재가 고려되고 있는데, 특히 표면에 고유한 흑색 구리(II) 산화물(CuO)을 형성하여 빛의 간섭을 줄이고 플레어(flare) 현상을 억제할 수 있기 때문에 스페이서로 적합하다. 따라서 본 연구에서는 선행 연구들과 특허들을 분석 및 정리하여 표준 구리 흑화 공정과 공정 조건을 제시하였다. 전체 공정은 수세(cleaning), 탈산화(deoxidizing), 활성화(activation), 흑화(blackening), 그리고 안정화(sealing)의 단위 공정들로 구성되는데, 각 단위 공정의 온도 및 활성화 용액의 농도 등의 공정 변수가 구리 시료(strip)의 흑화도에 미치는 영향을 파악하였다. 표준 공정 조건은 색차계로 측정된 구리 시료의 흑화도가 품질 만족(on-spec.) 조건에 부합하는가를 기준으로 결정되었다.

Keywords

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