介绍了含有棱镜系统的数字光处理器(DLP)投影仪连续变焦距远心镜头的设计。通过对DLP投影镜头与数字微反射镜器件之间的全反射棱镜系统进行分析，发现采用像方远心光路设计方法，可使投影系统产生的杂光大大减少。进一步研究变焦距系统远心光路的结构特征，得出了使系统在整个变焦过程中都处于远心位置的光阑轴向位移方程。借助给光阑固联一个透镜(与补偿组共同补偿变倍组)所产生的像面移动，得到了变焦曲线平缓、光焦度分配均匀且成像质量较好的投影镜头。

The continuous telecentric zoom lens for a digital light processor (DLP) projector with prisms is presented. The total internal reflection (TIR) prisms between the zoom lens and the digital micro-mirror device (DMD) are analyzed. To obstruct the false light,it is preferable that the projector zoom lens has a telecentric incident side. To study the structure of telecentric beam path for zoom lens system,the axial displacement equation for the stop was deduced,which keep the system telecentric in all zoom position. A thin lens group fixed with the stop shares the power of the others and makes the cam curve smooth.