阿贝式目镜是在目镜和十字刻线间装有一个全反射小三棱镜。光线由十字窗射到小三棱镜上，经全反射后，照亮十字刻线，通过物镜向外射出光线，当光线遇到与之垂直的平面镜反射后再进入望远镜，所成的绿十字像与十字刻线重合。利用阿贝式目镜可以借其自身发出的平行光束进行调准，故称为自准直望远镜。 Abbe eyepiece is equipped with a small total reflection prism between the eyepiece and the reticle. The light is emitted from the cross window to the small prism. After total reflection, it illuminates the cross line of reticle, and then radiates light through the objective lens. When the light meets the refle