车载平显系统(HUD)可以让驾驶员更快速地查看车速、导航等相关信息,缩短驾驶视觉盲区时间,减少交通事故,改善驾驶体验。为加快车载HUD的普及,研究基于数字微镜元件(DMD)的微型投影系统,并以符合车身结构的反射式光学系统为核心,给出了仿真模型。借助投射投影屏,图像多次反射后进入人眼,形成位于挡风玻璃前端的虚像。设计目标显示,虚像距离为2.5 m,驾驶员不需要改变视距便可查看图像内容;水平可视范围为140 mm,垂直可视范围为60 mm,得到眼睛在不同位置看到的图像的光学传递函数,均接近衍射极限,表明图像清晰,设计效果较好。图像视场角为水平12°,垂直6.75°,在不干扰驾驶员视线的情况下提供了足够的显示面积。

The head-up display (HUD) system can help drivers to check the speed, navigation, and other related information conveniently, shorten the visual blind spot, thus reduce traffic accidents, and improve the driving experience. In order to speed up the popularization of the vehicle-mounted HUDs, a mini-projector system based on the digital micro-mirror device (DMD) is proposed, which focuses on the reflective optical system conforming to the vehicle structures, and the simulation model is provided. The image enters into human eyes through multiple reflections by the projection screen, thus forming a virtual image in front of the windshield. The design result shows the virtual image distance can reach 2.5 m so that the driver can view the image without changing sight distance. The horizontal and vertical viewing ranges reach 140 mm and 60 mm, respectively. The optical transfer functions at different positions are all close to the diffraction limit, which indicates the clear image and good projection effect. The horizontal and vertical fields of view are 12° and 6.75°, respectively, which can provide sufficient display area without disturbing the drivers' visual field.