现行的照明用具一般体积较大、不易随身携带且不具备图像放大能力，为了给广大学习者尤其是视力不佳者提供一种全新的学习照明装置，设计了一种便携式放大视读屏。它具有柔光照明和图像放大双重功能：该屏利用梯形波导板的受抑全内反射原理，将侧面导入的LED光束从上下表面导出，实现了均匀的柔光照明功能；同时利用模压在波导板下表面的菲涅耳透镜实现了可调的图像放大功能。根据上述设计原理，通过ZEMAX软件对该视读屏的工作效果进行了理论模拟和参数优化，并制作了一块120 mm×80 mm×4 mm的视读屏，结果表明照明光线均匀柔和、放大效果清晰一致，成功实现了柔光照明和图像放大双重功能。

Traditional illuminating devices have disadvantages of big-volume,stationary and without image magnification. For the sake of supplying a novel illuminating device to the readers especially weak-eyed users,a portable magnifying visual screen is designed,which has advantages of uniform illumination and image magnification. It uses both the frustrated total internal reflection(FTIR)principle of trapezoidal waveguide to realize the visual screen's uniform illumination and Fresnel lens to realize adjustable image magnification. Based on the above principles,the operating effects are simulated and the key parameters of visual screen by ZEMAX software are optimized. A visual screen of 120 mm×80 mm× mm is also presented and demonstrated. Both the uniform illumination and image magnification functions of visual screen are successfully realized in the experiments.