为实现对导光板发光质量快速、精准的评判,找出亮度差异较大的区域进行优化设计,提出了一种新的基于图像处理技术的导光板优化设计方法,深入研究了导光板发光质量的评判标准。以灰度直方图表征光能分布,进而给出均匀度的评判公式,提出了均匀度评判精度P的概念,并且通过编程给出离散灰度级所对应的网点位置,从而实现精准优化。以184 mm×314 mm×0.55 mm的导光板为例进行仿真验证,针对优化过程中三个不同阶段的照度图,基于灰度直方图对其进行评价分析,给出了均匀度与精度的变化关系,并与现有评价方法作了比较。结果表明:以精度为前提的灰度直方图评判法能定量、客观、全面地评价导光板的发光质量,避免了现有评价法可能出现的偶然性偏差,同时提升了导光板的优化速度、精度;比较优化前后的导光板,其均匀度可提升64%,随着优化的递进,TracePro软件和九点法存在的偶然性误差逐渐减小,三者的评判结果趋于一致。

In order to realize the rapid and accurate evaluation of luminous quality of light guide plate (LGP) and find nonuniform areas to optimize, we propose a new design method based on image processing technology, the evaluation criteria of luminous quality of LGP is deeply researched. The light distribution is represented by gray histogram, the evaluation formula of uniformity is given and the concept of evaluation precision P is presented. Furthermore, the dots position corresponding to discrete grayscale is located with program, the accurate optimization is realized. The method is verified and simulated by taking 184 mm×314 mm×0.55 mm LGP for example. The relation between uniformity and precision is given by analyzing three stage irradiation maps based on gray histogram in the optimization process. The method is compared with conventional evaluation methods. Results show that the gray histogram method can evaluate luminous quality of LGP objectively and comprehensively on the premise of precision and the possible accidental deviation is avoided. The optimization speed and precision are improved. The uniformity of LGP can improve 64% after optimization. The accidental deviation is reduced gradually with TracePro and nine dots in the optimization process. What's more, the results tend to consistent with three evaluation methods.