大尺寸LED背光模组驱动及控制研究
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摘要
目前,整个平板显示行业在全球范围内快速增长,其中液晶显示屏在平板显示中占据主导地位。背光源作为液晶显示屏中的重要组成部分,长期以来主要使用的是冷阴极荧光管。随着发光二极管(Light Emitting Diode,LED)的发展,LED已经普遍应用于小尺寸液晶显示屏背光,并逐渐进入大尺寸液晶电视背光领域。本文主要围绕LED的驱动和控制,研究、设计并制作了大尺寸LED背光模组。
首先,根据液晶显示器的尺寸、亮度和均匀性等给定要求,确定了大尺寸LED背光模组中LED的选择、排布以及连接方式。根据液晶显示屏直下式背光模组的结构,设计并制作了LED背光模组,初步搭建起大尺寸LED背光模组系统的光学部分。
其次,LED的I-V特性具有非线性和单向导电性的特点,电压的微小变化会引起电流的较大变化,从而引起亮度的较大变化;电流过强会引起LED寿命的衰减,电流过弱会影响LED的发光强度。因此,大功率LED驱动应尽可能保证流过LED的电流维持在一个适当的恒定值。采用HV9911设计了恒流驱动电路,可以使流过LED的电流恒定,并提供了LED过流保护电路。
此外,电流波动以及温度变化都对LED的发光亮度有重要影响。论文采用HDJD-S831-QT333色彩传感器模块设计了色彩传感电路,监测背光模组出射光色度变化;利用DS18B20设计了温度传感电路,监测背光模组的工作温度。并根据CIE 1931-XYZ色度标准和红绿蓝三原色混色原理,利用可编程逻辑器件EP2C8T144C8完成了控制及反馈电路软硬件的设计,并对其部分性能进行了测试和分析。
At present, the entire Flat Panel Display (FPD) industries are growing rapidly in the world. In all types of FPD, Liquid Crystal Display (LCD) occupies a dominant position. In a long time, as an important part of LCD, backlight mainly uses Cold Cathode Fluorescent Lamp. With the development of Light Emitting Diode (LED), LED has been widely used in small LCD backlight, and is entering large size LCD-TV backlight areas. In this paper, on the basis of LED driving and controlling technology, we study, design and produce a large-size LED backlighting module.
First, according to the request for the size, brightness and uniformity of LCD, choosing, arranging and connecting LEDs are confirmed. Then we design and construct the optical parts of LED backlight, according to the structure of direct LCD backlight.
Second, the I-V characteristics of LED is nonlinear and unilateral conductive. Small changes in voltage will cause larger changes in current and brightness. The life of LED will decay, if there is too large current. However, weak current will affect the LED luminous intensity. Therefore, LED drivers should maintain the current appropriate and constant as much as possible. HV9911 is used to design a constant current driver, which can guarantee the current of LED constant, and provides a LED protective circuit.
Third, the brightness of the LED is affected by current and temperature. We design a color sensing circuit based on HDJD-S831-QT333 color sensor module, to monitor the chrominance changes in backlight module, and design a temperature monitoring circuit based on DS18B20, to monitor the work temperature of backlight module. On the basis of CIE 1931-XYZ color standards and red, green, blue color-mixture theory, using the FPGA chip EP2C8T144C8, we design the controlling and feedback circuit both in software and hardware, and test some parameters of it.
首先,根据液晶显示器的尺寸、亮度和均匀性等给定要求,确定了大尺寸LED背光模组中LED的选择、排布以及连接方式。根据液晶显示屏直下式背光模组的结构,设计并制作了LED背光模组,初步搭建起大尺寸LED背光模组系统的光学部分。
其次,LED的I-V特性具有非线性和单向导电性的特点,电压的微小变化会引起电流的较大变化,从而引起亮度的较大变化;电流过强会引起LED寿命的衰减,电流过弱会影响LED的发光强度。因此,大功率LED驱动应尽可能保证流过LED的电流维持在一个适当的恒定值。采用HV9911设计了恒流驱动电路,可以使流过LED的电流恒定,并提供了LED过流保护电路。
此外,电流波动以及温度变化都对LED的发光亮度有重要影响。论文采用HDJD-S831-QT333色彩传感器模块设计了色彩传感电路,监测背光模组出射光色度变化;利用DS18B20设计了温度传感电路,监测背光模组的工作温度。并根据CIE 1931-XYZ色度标准和红绿蓝三原色混色原理,利用可编程逻辑器件EP2C8T144C8完成了控制及反馈电路软硬件的设计,并对其部分性能进行了测试和分析。
At present, the entire Flat Panel Display (FPD) industries are growing rapidly in the world. In all types of FPD, Liquid Crystal Display (LCD) occupies a dominant position. In a long time, as an important part of LCD, backlight mainly uses Cold Cathode Fluorescent Lamp. With the development of Light Emitting Diode (LED), LED has been widely used in small LCD backlight, and is entering large size LCD-TV backlight areas. In this paper, on the basis of LED driving and controlling technology, we study, design and produce a large-size LED backlighting module.
First, according to the request for the size, brightness and uniformity of LCD, choosing, arranging and connecting LEDs are confirmed. Then we design and construct the optical parts of LED backlight, according to the structure of direct LCD backlight.
Second, the I-V characteristics of LED is nonlinear and unilateral conductive. Small changes in voltage will cause larger changes in current and brightness. The life of LED will decay, if there is too large current. However, weak current will affect the LED luminous intensity. Therefore, LED drivers should maintain the current appropriate and constant as much as possible. HV9911 is used to design a constant current driver, which can guarantee the current of LED constant, and provides a LED protective circuit.
Third, the brightness of the LED is affected by current and temperature. We design a color sensing circuit based on HDJD-S831-QT333 color sensor module, to monitor the chrominance changes in backlight module, and design a temperature monitoring circuit based on DS18B20, to monitor the work temperature of backlight module. On the basis of CIE 1931-XYZ color standards and red, green, blue color-mixture theory, using the FPGA chip EP2C8T144C8, we design the controlling and feedback circuit both in software and hardware, and test some parameters of it.
引文
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[2]贺智.我国LCD制造装备业的发展现状及思考.电子工业专用设备, 2007, 7: 1~5
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[8]林世宪,郭太良,林志贤. LCD背光源的最新进展.国外电子测量技术, 2006, 25(5): 1~3
[9]王晓明,郭伟玲,高国等. LED用于LCD背光源的前景展望.现代显示, 2005, 7: 24~28
[10]赵兴涛.背光源革命技术开辟液晶电视机新时代CCFL冷阴极荧光管与RGB-LED背光源技术大PK.家电大视野, 2007, 11: 34~38
[11] G. Harbers, C. G. A. Hoelen. High Performance LCD Backlighting Using High Intensity Red, Green and Blue Light Emitting Diodes. SID Symposium Digest of Technical Papers, 2001, 32(1): 702~705
[12] G. Harbers, W. Timmers, W. S. Smitt. LED Backlighting for LCD- HDTV. Journal of Society for Information Display, 2002, 10(4): 347~350
[13]雪生.用于LCD的LED背光源.现代显示, 2005, 7: 34~37
[14]黄杨程,夏勋力,陈波等.大尺寸液晶电视LED背光源的研制.半导体光电, 2007, 28(5): 642~644
[15]季旭东. LCD用的新型高效LED背光源.灯与照明, 2005, 29(3): 54~56
[16]王文根,李瑛,王秀如等.大尺寸TFT-LCD的LED背光技术.现代显示, 2006, 8: 59~63
[17] D. DeAgazio.关于LED背光源设计及制造的思考.现代显示, 2006, 1: 30~33
[18] C. M. Chang, Y. C. Fang, C. R. Lee. A New Design with Mixing RGB LED (Red, Green, Blue Light-Emitting Diode) for Modern LCD (Liquid Crystal Display) Backlight System. Proceedings of SPIE, 2006, 6338: 63380Q1~63380Q11
[19]刘敬伟,王刚,马丽等.大尺寸液晶电视用LED背光源的设计与制作.液晶与显示, 2006, 21(5): 539~544
[20]梁萌,王国宏,范曼宁等. LCD-TV用直下式LED背光源的光学设计.液晶与显示, 2007, 22(1): 42~46
[21] W. R. Scott, H. Konijn, W. S. Smitt, et al. High Brightness Direct LED Backlight for LCD-TV. SID Symposium Digest of Technical Papers, 2003, 34(1): 1262~1265
[22]朱海波,夏明哲,徐琼等.用RGB LED实现高亮度背光源.今日电子, 2007, 7: 47~49
[23] T. Koskela.如何驱动RGB LED与白光LED实现背光照明.电子与电脑, 2008, 3: 42~45
[24]索尼株式会社.用于驱动背光单元的装置和方法.日本,发明专利, 200580000861, 2006. 1~49
[25] A.斯廷森著.工程光度学与辐射度学. (第一版).刁永言,于铨林,谢立清译.北京:科学出版社, 1987
[26]薛朝华.颜色科学与计算机测色配色实用技术. (第一版).北京:化学工业出版社, 2004
[27]罗伯特.亨特. CIE色度学.江西建材, 1996, 4: 31~42
[28]郭凌华.对标准色度学系统颜色空间的理解.包装工程, 2003, 24(2): 13~14
[29] LUMILEDS LIGHTING. Luxeon DCC for LCD Backlighting. Application Brief. http://www.lumileds.com, 2005
[30]金尚忠,王东辉,周文等.发光二极管光谱参数测试方法的研究.光电子.激光, 2002, 13(8): 825~827
[31]李志鹏,栾新源.液晶显示用LED背光源的驱动电路.现代显示, 2007, 9: 51~54
[32] B. Santos.用于平板显示器的RGB LED.世界电子元器件, 2007, 4: 30~32
[33] S. Muthu, F. J. P. Schuurmans, M. D. Pashley. Red, Green, and Blue LEDs for White Light Illumination. IEEE Trans. on Quantum Electronics, 2002, 8: 333~338
[34] S. Muthu, F. J. P. Schuurmans, M. D. Pashley. Red, Green, and Blue LED Based White Light Generation: Issues and Control. Proceedings of Industry of Applications Conference, 2002, 1: 327~333
[35] S. Muthu, J. Gaines. Red Green and Blue LED-Based White Light Source: Implementation Challenges and Control Design. Proceedings of Industry Applications Conference, 2003: 515~522
[36] P. Deurenberg, C. Hoelen, J. V. Meurs, et al. Achieving Color Point Stability in RGB Multi-chip LED Modules Using Various Color Control Loops. Proceedings of SPIE Fifth International Conference on Solid State Lighting, 2005, 5941: 63~74
[37] K. C. Lee, S. H. Moon, B. Berkeley, et al. Optical Feedback System with Integrated Color Sensor on LCD. Sensors and Actuators A: Physical, 2006, 130-131: 214~219
[38] S. Y. Lee, J. W. Kwon, H. S. Kim, et al. New Design and Application of High Efficiency LED Driving System for RGB-LED Backlight in LCD Display. Proceedings of Power Electronics Specialists Conference, 2006: 1~5
[39]李军伟. LED的驱动电路研究: [硕士学位论文].大连:大连理工大学图书馆, 2007
[40]沙占友,文环明. DC/DC电源变换器的拓扑类型.电源技术应用, 2006, 9(6): 1~4
[41]林继刚,俞安琪. LED驱动电路简介.中国照明电器, 2007, 9: 10~13
[42] C. C. Chen, C. Y. Wu, T. F. Wu. Fast Transition Current-Type Burst-Mode Dimming Control for the LED Back-Light Driving System of LCD TV. Proceedings of Power Electronics Specialists Conference, 2006, 19: 1~7
[43] C. C. Chen, C. Y. Wu, T. F. Wu. LED Back-light Driving System for LCD Panels. Proceedings of Applied Power Electronics Conference, 2006: 381~385
[44] C. F. Chao, W. Cheng. A Backlight Scaling Algorithm for Minimizing Power Consumption of Minimization Field Sequential Displays.台湾显示科技研讨会, 2006
[45]黎平,周雒维.高亮度LED驱动器概述.电气应用, 2007, 26(6): 6～10
[46] S. Y. Lee, H. S. Kim, J. K. Kwon, et al. New Design of Integrated Power and Integrated Driver with LED Module (IP-IDLM) Driving System for LED Backlight in LCD. Industrial Electronics, 2007. ISIE 2007. IEEE International Symposium on, 2007, 4: 584~587
[47] SUPERTEX INC.. Switch-Mode LED Driver IC with High Current Accuracy, 9911. Datasheet. http://www.supertex.com, 2006
[48] ALTERA CORPORATION. CycloneⅡDevice Handbook, Volume 1. Handbook. http://www.altera.com, 2007
[49] AVAGO TECHNOLOGIES. HDJD-S831-QT333 Color Sensor Module. Datasheet. http://www.avagotech.com, 2006
[50] TEXAS INSTRUMENTS. 3.3-V 10-Bit Analog-to-Digital Converters with Serial Control and 11 Analog Inputs, TLV1543. Datasheet. http://www.ti.com, 2004
[51] MAXIM INTEGRATED PRODUCTS. Programmable Resolution 1-Wire Digital Thermometer, DS18B20. Datasheet. http://www.maxim-ic.com, 2001
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[54] C. P. Chao, L. D. Liao, C. W. Chiu. Design of A Novel LED Lens Cap and Optimization of LED Placement In A Large Area Direct Backlight for LCD-TVs. Proceedings of SPIE, 2006, 6196: 61960N1~61960N9
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[56]周晶晶,张永利,李阳等.场序彩色液晶显示器用LED背光源的研究.光电子技术, 2004, 24(3): 174~176
[57]周晶晶,张永利,李阳等. LED背光源用于场序彩色LCD的研究.现代显示, 2004, 6: 21~26
[2]贺智.我国LCD制造装备业的发展现状及思考.电子工业专用设备, 2007, 7: 1~5
[3]万长虹,王天科.液晶及其显示器原理分析.微处理机, 2005, 1: 61~64
[4]汪敏,夏咸军.新型LED背光源技术及应用.光电子技术, 2005, 25(4): 267~270
[5]茅于海.液晶电视LED背光技术.中国电子商情(基础电子), 2007, 7: 34~37
[6]陈路.液晶电视背光源LED开始取代CCFL.实用影音技术, 2008, 1: 6~9
[7]蔡振荣.大尺寸LED背光发展计划及进展.中国照明, 2005, 12: 18~22
[8]林世宪,郭太良,林志贤. LCD背光源的最新进展.国外电子测量技术, 2006, 25(5): 1~3
[9]王晓明,郭伟玲,高国等. LED用于LCD背光源的前景展望.现代显示, 2005, 7: 24~28
[10]赵兴涛.背光源革命技术开辟液晶电视机新时代CCFL冷阴极荧光管与RGB-LED背光源技术大PK.家电大视野, 2007, 11: 34~38
[11] G. Harbers, C. G. A. Hoelen. High Performance LCD Backlighting Using High Intensity Red, Green and Blue Light Emitting Diodes. SID Symposium Digest of Technical Papers, 2001, 32(1): 702~705
[12] G. Harbers, W. Timmers, W. S. Smitt. LED Backlighting for LCD- HDTV. Journal of Society for Information Display, 2002, 10(4): 347~350
[13]雪生.用于LCD的LED背光源.现代显示, 2005, 7: 34~37
[14]黄杨程,夏勋力,陈波等.大尺寸液晶电视LED背光源的研制.半导体光电, 2007, 28(5): 642~644
[15]季旭东. LCD用的新型高效LED背光源.灯与照明, 2005, 29(3): 54~56
[16]王文根,李瑛,王秀如等.大尺寸TFT-LCD的LED背光技术.现代显示, 2006, 8: 59~63
[17] D. DeAgazio.关于LED背光源设计及制造的思考.现代显示, 2006, 1: 30~33
[18] C. M. Chang, Y. C. Fang, C. R. Lee. A New Design with Mixing RGB LED (Red, Green, Blue Light-Emitting Diode) for Modern LCD (Liquid Crystal Display) Backlight System. Proceedings of SPIE, 2006, 6338: 63380Q1~63380Q11
[19]刘敬伟,王刚,马丽等.大尺寸液晶电视用LED背光源的设计与制作.液晶与显示, 2006, 21(5): 539~544
[20]梁萌,王国宏,范曼宁等. LCD-TV用直下式LED背光源的光学设计.液晶与显示, 2007, 22(1): 42~46
[21] W. R. Scott, H. Konijn, W. S. Smitt, et al. High Brightness Direct LED Backlight for LCD-TV. SID Symposium Digest of Technical Papers, 2003, 34(1): 1262~1265
[22]朱海波,夏明哲,徐琼等.用RGB LED实现高亮度背光源.今日电子, 2007, 7: 47~49
[23] T. Koskela.如何驱动RGB LED与白光LED实现背光照明.电子与电脑, 2008, 3: 42~45
[24]索尼株式会社.用于驱动背光单元的装置和方法.日本,发明专利, 200580000861, 2006. 1~49
[25] A.斯廷森著.工程光度学与辐射度学. (第一版).刁永言,于铨林,谢立清译.北京:科学出版社, 1987
[26]薛朝华.颜色科学与计算机测色配色实用技术. (第一版).北京:化学工业出版社, 2004
[27]罗伯特.亨特. CIE色度学.江西建材, 1996, 4: 31~42
[28]郭凌华.对标准色度学系统颜色空间的理解.包装工程, 2003, 24(2): 13~14
[29] LUMILEDS LIGHTING. Luxeon DCC for LCD Backlighting. Application Brief. http://www.lumileds.com, 2005
[30]金尚忠,王东辉,周文等.发光二极管光谱参数测试方法的研究.光电子.激光, 2002, 13(8): 825~827
[31]李志鹏,栾新源.液晶显示用LED背光源的驱动电路.现代显示, 2007, 9: 51~54
[32] B. Santos.用于平板显示器的RGB LED.世界电子元器件, 2007, 4: 30~32
[33] S. Muthu, F. J. P. Schuurmans, M. D. Pashley. Red, Green, and Blue LEDs for White Light Illumination. IEEE Trans. on Quantum Electronics, 2002, 8: 333~338
[34] S. Muthu, F. J. P. Schuurmans, M. D. Pashley. Red, Green, and Blue LED Based White Light Generation: Issues and Control. Proceedings of Industry of Applications Conference, 2002, 1: 327~333
[35] S. Muthu, J. Gaines. Red Green and Blue LED-Based White Light Source: Implementation Challenges and Control Design. Proceedings of Industry Applications Conference, 2003: 515~522
[36] P. Deurenberg, C. Hoelen, J. V. Meurs, et al. Achieving Color Point Stability in RGB Multi-chip LED Modules Using Various Color Control Loops. Proceedings of SPIE Fifth International Conference on Solid State Lighting, 2005, 5941: 63~74
[37] K. C. Lee, S. H. Moon, B. Berkeley, et al. Optical Feedback System with Integrated Color Sensor on LCD. Sensors and Actuators A: Physical, 2006, 130-131: 214~219
[38] S. Y. Lee, J. W. Kwon, H. S. Kim, et al. New Design and Application of High Efficiency LED Driving System for RGB-LED Backlight in LCD Display. Proceedings of Power Electronics Specialists Conference, 2006: 1~5
[39]李军伟. LED的驱动电路研究: [硕士学位论文].大连:大连理工大学图书馆, 2007
[40]沙占友,文环明. DC/DC电源变换器的拓扑类型.电源技术应用, 2006, 9(6): 1~4
[41]林继刚,俞安琪. LED驱动电路简介.中国照明电器, 2007, 9: 10~13
[42] C. C. Chen, C. Y. Wu, T. F. Wu. Fast Transition Current-Type Burst-Mode Dimming Control for the LED Back-Light Driving System of LCD TV. Proceedings of Power Electronics Specialists Conference, 2006, 19: 1~7
[43] C. C. Chen, C. Y. Wu, T. F. Wu. LED Back-light Driving System for LCD Panels. Proceedings of Applied Power Electronics Conference, 2006: 381~385
[44] C. F. Chao, W. Cheng. A Backlight Scaling Algorithm for Minimizing Power Consumption of Minimization Field Sequential Displays.台湾显示科技研讨会, 2006
[45]黎平,周雒维.高亮度LED驱动器概述.电气应用, 2007, 26(6): 6～10
[46] S. Y. Lee, H. S. Kim, J. K. Kwon, et al. New Design of Integrated Power and Integrated Driver with LED Module (IP-IDLM) Driving System for LED Backlight in LCD. Industrial Electronics, 2007. ISIE 2007. IEEE International Symposium on, 2007, 4: 584~587
[47] SUPERTEX INC.. Switch-Mode LED Driver IC with High Current Accuracy, 9911. Datasheet. http://www.supertex.com, 2006
[48] ALTERA CORPORATION. CycloneⅡDevice Handbook, Volume 1. Handbook. http://www.altera.com, 2007
[49] AVAGO TECHNOLOGIES. HDJD-S831-QT333 Color Sensor Module. Datasheet. http://www.avagotech.com, 2006
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