构建了一种发光二极管(LED)显示屏灰度等级调制模型以实现其灰度调制并获取优选扫描时钟。根据脉宽调制的特点，将灰度调制过程分为基本灰度等级调制和扩充灰度等级调制来构建灰度等级的调制模型。通过分析模型各参数关系，提出一种优选扫描时钟的选取方法和扫描时钟富裕系数的概念，并在此基础上总结了LED显示屏显示控制优化途径。最后，通过硬件平台验证并实现了该灰度等级模型。实验结果表明：对于4扫的LED显示屏，选取最小响应脉宽小于等于40 ns的驱动芯片可使刷新率为300 Hz、移存长度为128个像素点、灰度等级为14 bit的优选扫描时钟为10 MHz，同时其亮度利用率达到90%，最大扫描时钟富裕系数达到3.5。采用该模型实现灰度等级调制，可以满足LED显示屏的显示要求，可应用于实际工程项目。

A gray scale modulation model was established to achieve the Light Emission Dode(LED) display gray scale modulation and obtain the optimal scan clock. According to the characteristic of pulse width modulation, the gray modulation process was divided into the basic gray scale modulation and the expansion gray scale modulation to construct a gray scale modulation model. Through the analysis of the parameters of the model, a kind of selection method for the optimal scan clock was put forward and a concept of scan clock affluent coefficient was proposed. On the basis of these, an approach to optimize display screen control was summarized. Finally, the gray scale model was verified and implemented through the hardware. The experimental results show that for the four-scanning LED display screen, selecting the driving chip whose minimum pulse width is less than or equal to 40 ns can realize the optimal scan clock to be 10 MHz at a refresh rate of 300 Hz , a shift register length of 128 pixels, and the gray scale of 14 bit. Meanwhile, its brightness utilization rate reaches 90% and the maximum scanning clock affluent coefficient reaches 3.5. The model can be used to achieve gray scale modulation, and can meet the requirements of LED screen display in practical engineering applications.