研究生: |
廖家成 Chia-Cheng Liao |
---|---|
論文名稱: |
應用於光電顯示與照明科技之發光二極體輻射分佈特徵的快速量測系統 A Fast LED Radiation Pattern Characterization System for Display and Illumination Technologies |
指導教授: |
張國維
Chang, Gao-Wei |
學位類別: |
碩士 Master |
系所名稱: |
機電工程學系 Department of Mechatronic Engineering |
論文出版年: | 2007 |
畢業學年度: | 95 |
語文別: | 中文 |
論文頁數: | 76 |
中文關鍵詞: | 發光二極體 、光輻射分佈 、光電顯示科技 、照明科技 |
英文關鍵詞: | light emitting diode, LED, radiation pattern, display technology, illumination technology |
論文種類: | 學術論文 |
相關次數: | 點閱:242 下載:13 |
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發光二極體(light emitting diode, LED)具備省電、壽命長、色彩多變、環保、以及反應速度快等優點,已取代傳統光源,成為備受矚目的新一代光源科技。為了滿足LED於不同應用上需求(例如,光電顯示與照明科技等),準確地檢測或鑑定LED輻射樣本(radiation pattern)是非常重要的。例如,測定LED的輻射樣本,能妥善且有效地利用LED的視角(viewing angle)與發光效率(lighting efficiency),並藉此改善LED熱耗散(thermal dissipation)或能量消耗(power consumption)、以及使用人員安全性的問題。因此,發展LED光輻射分佈特徵量測技術在光電顯示與照明科技與產業有相當重要的意義。
本論文的研究目的主要可區分為以下兩個重點:
(1) 首先,我們針對以光二極體(photodiode, PD)感測技術為基礎的系統組態,來進行理論分析與數學描述。我們利用角空間頻率(angular spatial frequency)之概念來詮釋系統的量測解析度,並經由實驗來驗證PD感測技術的空間濾波效應(spatial filtering effect),以及LED輻射樣本的空間頻率。亦針對不同的量測方法(如,二維照度量測法),經由實驗驗證的方式來進行量化分析,並比較出各種方法之間的優劣點。
(2) 再者,我們根據性能評估的結果,提出一套快速且較準確的量測系統,來測定各種不同亮度LED的輻射樣本。在此論文中,一個快速鎖定放大(lock-in amplifier, LIA)技術被呈現出來,此技術的功能在於能有效地即時濾除雜訊/雜光,避免系統受外界雜訊干擾而增加量測的不確定性。
本論文所提出的系統架構僅含有一個PD感測電路、兩個步進馬達、一個快速LIA裝置、以及一組數位訊號處理(digital signal processing, DSP)平台,其系統結構簡單,且具有高成本效益。針對此系統,論文中我們利用漸進的方式,依循學理、模擬、實驗與系統製作的方法,並且說明整體的可行性分析。實驗的結果顯示此方法所量測的結果是相當令人滿意的。
最後,我們利用此系統來進行多顆LED光源模組的均勻度測試,經由此系統我們能有效地測定光源模組的均勻性,並決定較佳的LED陣列排列方式。相信此一論文對於LED顯示/照明技術之學術研究與產業發展將有相當大的助益。
For years, light-emitting diodes (LEDs) have been recognized as a generation of new light sources because they possess the properties of energy-saving, environmental friendly, and long lifetime, and those surpassing in traditional lighting. To satisfy the requirements for different applications, such as for displays and illuminations, determining LED radiation patterns is important to utilizing their viewing angle and lighting efficiency, so that the difficulties of thermal dissipation (power consumption) and safety are resolved.
To achieve the objectives, a fast LED radiation pattern characterization system is proposed. In this thesis, we focus on two major works as follows. The first is to give a mathematical formulation for the PD sensing measurement methods and to quantitatively analyze the different methods (e.g., two-dimensional irradiation measurement) through experiments. In the experiments, the spatial bandwidth of LED radiation patterns and the spatial filtering effect due to PD sensing are to be verified. The second is to design and develop a fast measurement system for the radiation patterns of wide-range brightness LEDs. Due to the real-time noise suppression performance of the proposed system, the requirements of fast of quality control and classification for a variety of LEDs will be achieved.
In this thesis, a fast lock-in amplifier (LIA) technique has been presented to perform real-time noise suppression. The LIA scheme of the system simply employs a PD sensing circuit, two stepping motors, a fast analog dual LIA device, and a DSP-platform to achieve the measurement. Thus, the configuration of such a system is quite simple and it is consequently cost-effective. The system has been achieved and verified through the experiments. Experimental results indicate that the proposed system gives a satisfactory result. It appears that the proposed approach can establish an accurate optical modeling for LED devices. Finally, the proposed system can evaluate the uniformity of the multiple-LED module to determine the optimum packing density of LED arrays for display/illumination technologies. We expect that it would be highly beneficial to the development of related industries for the techniques of LED applications/manufacturing.
[1] Source: IEK, 產值突破一兆 台灣平面顯示器產業勢有可為, Oct. 2006. [On-line] Available: http://www.hope.com.tw/
[2] Source: IEK, 台灣平面顯示器產值2010年挑戰2兆元, Dec. 2006. [On-line] Available: http://news.epochtimes.com.tw/6/12/6/42658.htm
[3] R. West, et al., “High brightness direct LED backlight for LCD-TV,” SID 03 DIGEST, 2003.
[4] K. Kaninuma, “Technology of wide color gamut backlight with light-emitting diode for liquid crystal display television,” Appl. Phy., vol. 45, no. 5B, pp. 4330-4334, 2006.
[5] S. Chang and J.B. Yoon, “Microlens array diffuser for a light-emitting diode backlight system,” OSA, OPTICS LETTERS, vol. 31, no. 20, pp.3016-3018, Oct. 2006.
[6] I. Moreno, “Design of LED spherical lamps for uniform far-field illumination,” Proc. of SPIE, vol. 6040, 60462E-1.
[7] Source: PIDA, compiled by FPDisplay, Mar. 2006. [On-line] Available: http://www.fpdisplay.com/news_info/Shtml/20060325_11025.htm
[8] M. Anandan, “LED backlight for LCD/TV monitor: issues that remain,” SID 06 DIFEST, pp. 1509-1512, 2006.
[9] J. M. Benavide and R. H. Webb, “Optical characterization of ultrabright LEDs,” Applied Optics, vol. 44, no. 19, pp. 4000-4003, July 2005.
[10] TechK. Godo, et al., “Development of a total luminous flux measurement facility for LEDs at the national metrology institute of Japan,” Proceedings of the 9th International Conference on New Developments and Application in Optical Radiometry, pp.199-200, 2005.
[11] Bredemeier, et al., “Ray data of LEDs and Arc lamps,” ISAL 2005; Darmstadt University of Technology, pp. 1030-1037, 2005
[12] O. Schmatov and Z.S. Li, “Truncated-inverted-pyramid light emitting diode geometry optimization using ray tracing technique,” IEE Proc-Optoelectron., vol.150, no. 3, pp.273-277, Jun. 2003.
[13] Instrument datasheet: PRO-LiTE technology, IS-VA Imaging Sphere. [On-line] Available: http://www.pro-lite.uk.com/
[14] Source: Wikipedia, the free encyclopedia, Radiation Pattern [On-line] Available: http://en.wikipedia.org/wiki/Radiation_pattern.
[15] E. Uiga, Optoelectronics, Englewood Cliffs, Prentice Hall, New Jersey, 1995.
[16] I. Moreno, et al., “Designing light-emitting diode arrays for uniform near-field radiance,” Applied Optics, vol.45, no. 10, pp.2265-2271, Apr. 2006.
[17] I. Moreno, et al., “Uniform illumination of distant targets using a spherical light-emitting diode array,” Optical Engineering, vol. 46(3), no. 033001, pp. 1-7, Mar. 2007.
[18] I. Moreno, et al., “Spatial distribution of LED radiation,” SPIE-OSA, vol. 6342, no. 664216-1, 2006.
[19] C. H. Ho, “A practical and inexpensive design for measuring the radiation pattern and luminescent spectra of optoelectronic devices,” AIP, Rev. Sci. Instrum., vol. 72, no. 7, July, 2001.
[20] J.L. Guttman, et al., “Real-time scanning goniometric radiometer for rapid characterization of laser diodes and VCSELs,” Photon, Inc. Technique handbook, Jue. 2001.
[21] C. Sun, et al., “Optical modeling for LED in mid-field region,” SPIE, vol. 6342, no. 634217, 2006.
[22] G. D. Boreman, Modulation Transfer Function in Optical and Electro-Optical System, SPIE PRESS, 2001.
[23] J. H. McClellan, et al., Signal Processing First, Pearson Prentice Hall, 2003.
[24] G. W. Chang, Z. M Yeh, S. Y. Pan, C. C. Liao, and H. M. Chang, “A Progressive Design Approach to Enhance Project-based Learning in Applied Electronics through an Optoelectronic Sensing Project,” revised to IEEE Trans. on Education, 2006. (NSC 94-2516-S-003-016)
[25] A. S. Sedra and K. C. Smith, Microelectronics circuits, 4nd ed., Oxford, 1998.
[26] Gaspar, et al., “Digital lock in amplifier: study, design and development with a digital signal processor,” J. Gaspar et al. / Microprocessors and Microsystems, vol. 28, pp. 157-162, 2004.
[27] M. O. Sonnaillon, et. al., ”Implementation of a high-frequency digital lock-in amplifier,” IEEE, CCECE/CCGEI, Saskatoon, pp.1229-1232, 2005.
[28] J. G. Graeme, Photodiode Amplifiers: Op Solutions, McGraw-Hill, New York, 1996.
[29] T. E. Jenkins, Optical Sensing Techniques and Signal Processing, Englewood Cliffs, Prentice Hall, New Jersey, 1987.
[30] G. W. Chang, Teaching handout: Fourier optics, OESL, NTNU, 2006.