| 학회 | 한국재료학회 |
| 학술대회 | 2018년 봄 (05/16 ~ 05/18, 삼척 쏠비치 호텔&리조트) |
| 권호 | 24권 1호 |
| 발표분야 | 1. 마이크로 LED 제작 및 응용기술(Micro LEDs: fabrication and applications)-오거나이저: 이인환 교수(고려대) |
| 제목 | Highly efficient 32x32 pixelated micro-LED arrays for smart headlamp of vehicles |
| 초록 | Micro-light-emitting diode (μ-LED) arrays are attracting great attention owing to their potential applications in large-size displays, visible light communication, and optogenetic neural stimulation. [1-3]. Recently, individually controllable μ-LED arrays have recently been implemented to achieve a high-resolution adaptive driving beam (ADB) or advanced forward lighting system (AFS) for headlights of vehicles, which have 64 μ-LED pixels per 1 mm2, a pixel area of 115 μm x 115 μm, and pixel pitch of 125 μm in both directions [4]. μ-LED arrays for a high-resolution ADB/AFS have their unique benefits such as individual controllability, scalability, and design flexibility. In order to realize high-brightness InGaN based individually addressable μ-LED arrays for the high-resolution ADB/AFS application, the luminous flux as well as thermal dissipation of the μ-LED arrays should be further improved. This presentation provides an overview about μ-LED array lighting sources for high resolution ADB headlamp of vehicles, and focus on improvement of external quantum efficiency (EQE) of the μ-LED arrays, since realization of high brightness InGaN/GaN μ-LED arrays for the high-resolution ADB for headlamp requires the achievement of high EQE. For this purpose, we fabricated InGaN-based μ-LED arrays with low reflectivity and small coverage of the p-type elec-trode to p-GaN on the MESA area (uncontrolled sample) and with high reflectivity and large coverage of the p-type electrode (controlled sample). Both the InGaN based μ-LED arrays consisted of 256 μ-LED pixels per 2-mm x 2-mm area, with a pixel area of 115 μm x 115 μm and pixel pitches of 125, 130, or 140 μm in both directions. Both devices allowed for individual control of the μ-LED pixels and yielded similar electrical properties. The light output power of the controlled sample was greatly improved by 3.7 times at an injection current of 100 mA compared to that of the uncontrolled sample. This result shows that the reflectivity and coverage are important factors for improving the light output power of μ-LED arrays. The variation of dark spaces in several emission images were investigated as a function of the pixel pitch for controlled samples at an injection current of 20 mA. Under an injection current of 20 mA, the dark space of the control array was greatly reduced at a pixel pitch of 125 μm. Reference [1] J. Herrnsdorf, J. J. D. McKendry, S. Zhang, E. Xie, R. Ferreira, D.Massoubre, A. M. Zuhdi, R. K. Henderson, I. Underwood, S. Watson, A.E. Kelly, E. Gu, M. D. Dawson, “Active-matrix GaN micro light-emitting diode display with unprecedented brightness,” IEEE Trans. Electron Devices, vol. 62, pp. 1918–1925, 2015. [2] M.S. Islim, R.X. Ferreira, X. He, E. Xie, S. Videv, S. Viola, S. Watson, N. Bamiedakis, R.V. Penty, I.H. White, A.E. Kelly, E. Gu, H. Haas, M. D. Dawson, “Towards 10 Gb/s orthogonal frequency division multiplexing-based visible light communication using a GaN violet micro-LED” Phot. Res., vol. 5, pp. A35-A43, 2017. [3] B. McGovern et al., "A new individually addressable micro-LED array for photogenetic neural stimulation", IEEE Trans. Biomed. Circuits Syst., vol. 4, pp. 469-476, 2010. [4] S. Grötsch, M. Brink, R. Fiederling, T. Liebetrau, I. Möllers, J. Moisel, H. Oppermann, and A. Pfeuffer, "μAFS High Resolu-tion ADB, AFS Solution," SAE Technical Paper, 2016-01-1410, 2016, doi:10.4271, 2016-01-1410 |
| 저자 | 곽준섭 |
| 소속 | 순천대 |
| 키워드 | GaN; micro-LED; smart headlamp |
