Korean Journal of Optics and Photonics (한국광학회지)

Optical Society of Korea (한국광학회)
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Backward Testing Method of MTF measurement for optical engine of CRT of rear projection HDTV

후면투사식 CRT 고화질 텔레비전용 광학엔진의 변조전달함수 측정을 위한 후방검사 변조전달함수 측정법

  • Song, Jong-Sup (Optical Module R&D Group, Optics Division, Samsung Electro-mechanics Co. Ltd.) ;
  • Jo, Jae-Heung (Dept. of Physics, Hannam University) ;
  • Hong, Sung-Mok (Dept. of Physics, Hannam University) ;
  • Lee, Yun-Woo (Photometry & Imaging Optics Group, Korea Research Institute of Standards and Science) ;
  • Song, Jae-Bong (Photometry & Imaging Optics Group, Korea Research Institute of Standards and Science) ;
  • Lee, Hoe-Yun (Photometry & Imaging Optics Group, Korea Research Institute of Standards and Science) ;
  • Lee, In-Won (Photometry & Imaging Optics Group, Korea Research Institute of Standards and Science)
  • 송종섭 ((주)삼성전기 광사업부 광모듈사업팀 광모듈개발그룹) ;
  • 조재흥 (한남대학교 광·전자물리학과) ;
  • 홍성목 (한남대학교 광·전자물리학과) ;
  • 이윤우 (한국표준과학연구원 광도영상그룹) ;
  • 송재봉 (한국표준과학연구원 광도영상그룹) ;
  • 이회윤 (한국표준과학연구원 광도영상그룹) ;
  • 이인원 (한국표준과학연구원 광도영상그룹)
  • Published : 2005.02.01
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Abstract

Because of the wide plane and the curved field of CRT rear projection high definition television, its MTF(modulation transfer function) can't be easily measured by the usual forward testing method. Then we propose a backward testing method for the MTF so that the object plane and the image analyzer of forward testing are located at positions opposite each other. We prefer to use the backward testing method because the forward testing method has poor accuracy caused by very small numerical aperture, low spatial resolutions, and long depth of focus. We found that the backward testing method was very easy to align and had high repeatability. We confirmed the confidence of results obtained by the backward testing method in comparison with designed results.

후면투사방식의 CRT(Cathod Ray Tube) 고화질 텔레비젼용 광학엔진은 큰 화면과 굽은 필드 때문에 일반적인 전방검사 MTF(modulation transfer function)로는 측정이 어렵다. 이러한 광학엔진의 MTF를 측정하기 위하여 광학엔진이 놓인 물체면과 상분석기의 위치를 서로 바꾸는 후방검사 MTF방법을 제안하고 이에 따른 MTF 측정장비를 구성하였다. 이러한 CRT HDTV용 광학엔진을 위한 후방검사 MTF측정법은 작은 수치개구(NA), 낮은 분해능, 긴 초점심도들 때문에 정밀도가 낮아지는 전방검사 MTF 측정법보다 사용하기가 훨씬 더 좋으며, 정렬이 매우 용이하고 측정반복성이 매우 좋다. 이 방법으로 측정한 MTF값과 설계된 MTF를 비교함으로써 이 방법의 신뢰성을 확인하였다.

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References

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