The Journal of the Korea institute of electronic communication sciences (한국전자통신학회논문지)

Korea Institute of Electronic Communication Science (한국전자통신학회)
권호 표지
DOI QR코드

DOI QR Code

5-TFT OLED Pixel Circuit Compensating Threshold Voltage Variation of p-channel Poly-Si TFTs

p-채널 다결정 실리콘 박막 트랜지스터의 문턱전압 변동을 보상할 수 있는 5-TFT OLED 화소회로

  • 정훈주 (금오공과대학교 전자공학부)
  • Received : 2013.12.05
  • Accepted : 2014.03.07
  • Published : 2014.03.31
Download PDF
⟨ Previous Next ⟩

Abstract

This paper proposes a novel OLED pixel circuit to compensate the threshold voltage variation of p-channel low temperature polycrystalline silicon thin-film transistors (LTPS TFTs). The proposed 5-TFT OLED pixel circuit consists of 4 switching TFTs, 1 OLED driving TFT and 1 capacitor. One frame of the proposed pixel circuit is divided into initialization period, threshold voltage sensing and data programming period, data holding period and emission period. SmartSpice simulation results show that the maximum error rate of OLED current is -4.06% when the threshold voltage of driving TFT varies by ${\pm}0.25V$ and that of OLED current is 9.74% when the threshold voltage of driving TFT varies by ${\pm}0.50V$. Thus, the proposed 5T1C pixel circuit can realize uniform OLED current with high immunity to the threshold voltage variation of p-channel poly-Si TFT.

본 논문에서는 p-채널 저온 다결정 실리콘 박막 트랜지스터의 문턱전압 변동을 보상할 수 있는 새로운 OLED 화소회로를 제안하였다. 제안한 5-TFT OLED 화소회로는 4개의 스위칭 박막 트랜지스터, 1개의 OLED 구동 박막 트랜지스터 및 1개의 정전용량으로 구성되어 있다. 제안한 화소회로의 한 프레임은 초기화 구간, 문턱전압 감지 및 데이터 기입 구간, 데이터 유지 구간 및 발광 구간으로 나누어진다. SmartSpice 시뮬레이션 결과, 구동 트랜지스터의 문턱전압이 ${\pm}0.25V$ 변동 시 최대 OLED 전류의 오차율은 -4.06%이였고 구동 트랜지스터의 문턱전압이 ${\pm}0.50V$ 변동 시 최대 OLED 전류의 오차율은 9.74%였다. 따라서 제안한 5T1C 화소회로는 p-채널 다결정 실리콘 박막 트랜지스터의 문턱전압 변동에 둔감하여 균일한 OLED 전류를 공급함을 확인하였다.

Keywords

References

  1. B. Kim, "A Software for Subscriber-Oriented IPTV Service Quality Measurement," J. of The Korea Institute of Electronic Communication Sciences, vol. 5, no. 3, 2010, pp. 269-274.
  2. S.-H. Rha and H.-S. Shin, "A Study on the IPTV's Element and Core Techniques," J. of The Korea Institute of Electronic Communication Sciences, vol. 4, no. 4, 2009, pp. 253-258.
  3. I.-K. Kim and W.-J. Park, "The Influence of Users' Perception of Digital Convergence Media upon Use Intention," J. of The Korea Institute of Electronic Communication Sciences, vol. 6, no. 3, 2011, pp. 363-369.
  4. H.-J. Chung, "A Voltage Programming AMOLED Pixel Circuit Compensating Threshold Voltage Variation of n-channel Poly-Si TFTs," J. of The Korea Institute of Electronic Communication Sciences, vol. 8, no. 2, 2013, pp. 207-212. https://doi.org/10.13067/JKIECS.2013.8.2.207
  5. S.-K. Hong, D.-H. Oh, S.-H. Jeong, Y.-J. Park, B.-K. Kim, Y.-M. Ha, and J. Jang, "Source Driver Channel Reduction Schemes Employing Corresponding Pixel Alignments for Current Programming Active-Matrix Organic Light- Emitting Diode Displays," Jpn. J. of Applied Physics, vol. 47, no. 3, 2008, pp. 1901-1905. https://doi.org/10.1143/JJAP.47.1901
  6. J. L. Sanford and F. R. Libsch, "TFT AMOLED pixel circuits and driving methods," SID Int. Symp. Digest, Baltimore, USA, 2003, pp. 10-13.
  7. Y. He, R. Hattori, and J. Kanicki, "Current-Source a-Si : H Thin-Film Transistor Circuit for Active-Matrix Organic Light- Emitting Displays," IEEE ELECTRON DEVICE LETTERS, vol 21, no. 12, 2000, pp. 590-592. https://doi.org/10.1109/55.887475