Journal of the Semiconductor & Display Technology (반도체디스플레이기술학회지)

The Korean Society Of Semiconductor & Display Technology (한국반도체디스플레이기술학회)
권호 표지

Study on the Reliability of an OLED Pixel Circuit Using Transient Simulation

과도상태 시뮬레이션을 사용한 OLED 픽셀 회로의 신뢰성 분석 방안 연구

  • Jung, Taeho (Department of Electronic and IT Media Engineering, Seoul National University of Science and Technology)
  • 정태호 (서울과학기술대학교 전자IT미디어공학과)
  • Received : 2021.12.03
  • Accepted : 2021.12.15
  • Published : 2021.12.31
Download PDF
⟨ Previous Next ⟩

Abstract

The brightness of the Organic Light Emitting Diode (OLED) display is controlled by thin-film transistors (TFTs). Regardless of the materials and the structures of TFTs, an OLED suffers from the instable threshold voltage (Vth) of a TFT during operation. When designing an OLED pixel with circuit simulation tool such as SPICE, a designer needs to take Vth shift into account to improve the reliability of the circuit and various compensation methods have been proposed. In this paper, the effect of the compensation circuits from two typical OLED pixel circuits proposed in the literature are studied by the transient simulation with a SPICE tool in which the stretched-exponential time dependent Vth shift function is implemented. The simulation results show that the compensation circuits improve the reliability at the beginning of each frame, but Vth shifts from all TFTs in a pixel need to be considered to improve long-time reliability.

Keywords

Acknowledgement

이 연구는 서울과학기술대학교 교내연구비의 지원으로 수행되었습니다.

References

  1. G. W. Shim, W. Hong, J. Cha, J. H. Park, K. J. Lee, and S. Choi, "TFT Channel Materials for Display Applications: From Amorphous Silicon to Transition Metal Dichalcogenides", Adv. Mater., vol. 32, pp. e1907166-n/a, 2020.
  2. Jae Won Choi, Jin Jang, Ja Hun Koo, Ji Ho Hur, Moon Hyo Kang, and Young Seoung Kim, "A New Pixel Design of Active-Matrix Organic Light-Emitting Diode Display Using Amorphous-Silicon Backplane", J. Korean Phys. Soc., vol. 49, pp. 816-819, 2006.
  3. A. Sodhani and K. Kandpal, "Design of threshold voltage insensitive pixel driver circuitry using a-IGZO TFT for AMOLED displays", Microelectr. J., vol. 101, pp. 104819, 2020. https://doi.org/10.1016/j.mejo.2020.104819
  4. B. Chen, Y. Tai, Y. Kuo, C. Tsai, and H. Cheng, "New pixel circuits for driving active matrix organic light emitting diodes", Solid-State Electron., vol. 50, pp. 272-275, 2006. https://doi.org/10.1016/j.sse.2005.12.016
  5. C. Fan, F. Tseng, H. Lai, B. Sun, K. Chao, and Y. Chen, "A Novel LTPS-TFT Pixel Circuit to Compensate the Electronic Degradation for Active-Matrix Organic Light-Emitting Diode Displays", Int. J. Photoenergy, vol. 2013, pp. 1-6, 2013.
  6. H. Chung, "Novel 5T1C pixel circuit for high-ppi AMOLED displays with n-channel LTPS TFTs", J. Inf. Display, vol. 20, pp. 39-43, 2019. https://doi.org/10.1080/15980316.2019.1569565
  7. C. Fan, H. Tsao, C. Chen, P. Chou, and W. Lin, "New Low-Voltage Driving Compensating Pixel Circuit Based on High-Mobility Amorphous Indium-Zinc-Tin-Oxide Thin-Film Transistors for High-Resolution Portable Active-Matrix OLED Displays", Coatings, vol. 10, pp. 1, 2020. https://doi.org/10.3390/coatings10010001
  8. C. Chen, J. Kanicki, K. Abe, and H. Kumomi, "P-14: AM-OLED Pixel Circuits Based on a-InGaZnOThin Film Transistors", SID Int. Symp. Dig. Tec., vol. 40, pp. 1128-1131, 2009. https://doi.org/10.1889/1.3256484
  9. J. Ke, L. Deng, L. Zhen, Q. Wu, C. Liao, H. Luo, and S. Huang, "An AMOLED Pixel Circuit Based on LTPS Thin-film Transistors with Mono-Type Scanning Driving", Electronics, vol. 9, pp. 574, 2020. https://doi.org/10.3390/electronics9040574
  10. H. Lee, J. Kanicki, Y. C. Lin, and H. Shieh, "70.3: Current-Scaling a-Si:H TFT Pixel Electrode Circuit for AM-OLEDs", SID Int. Symp. Dig. Tec., vol. 37, pp. 1968-1971, 2006. https://doi.org/10.1889/1.2451422
  11. T. Jung, "Implementation of Stretched-Exponential Time Dependence of Threshold Voltage Shift in SPICE", J. of KSDT, vol. 19, no. 1, 2020.