无汞平面光源区域调光方法的设计与实现

Local Dimming Method for Mercury Free Flat Fluorescent Lamp with Arc-Like Electrode

为了提高无汞平面光源(FFL)的发光效率和避免放电收缩,设计并制作了一种新型的具有弧形电极结构的无汞平面光源,该结构光源在单极性脉冲作用下具有高亮度、高发光效率以及高工作余度等特性;另外,设计了一种可实现区域调光的电极结构,基于该结构光源,提出了一种调光方法及调光电路;最后,完成了基于81cm(32in)无汞平面光源的模型验证。实验结果表明:所设计的平面光源可采用脉冲密度调制或者脉冲频率调制的调光方法来实现亮度的行列可调,在最大亮度时,其功耗为256W;而当其亮度降低至400cd/m2时,其功耗降低至15W,此时FFL有最高发光效率为29lm/W。采用区域调光方法可以在获得100%～6%宽范围亮度调节的同时,有效降低FFL背光源的功耗。

An electrode structure for local dimming was presented in this article with a newly developed co-planar type mercury free flat fluorescent lamp（FFL）,which showed a large operating margin,high luminance and high luminous efficacy in the case of unipolar driving.Furthermore,the dimming circuit and method were presented and a 81 cm（32 in） FFL prototype was built and verified.The experiment results show that a local dimming can be implemented horizontally and vertically with the proposed electrode structure by pulse density modulation（PDM） method or frequency modulation method.It also demonstrates that the power consumption can be reduced since the light output of FFL can be controlled.The power varied with brightness from 100% of the max power consumption 256 W to 6% of the max power consumption,the luminous efficacy increased as the luminance decreased,a max system efficiency about 29 lm/W could be obtained when the luminance decreased to 400 cd/m2 and a dimming range about 100%~6% can be achieved by using the proposed method.