运用垂直定向反射光显示光滑物面上的弱反差指印和潜在汗液指印,是拍照提取指纹经常使用的方法,但是,产生垂直定向反射光需要专门的光学器材,因价格、实用性能等多方面的原因,这种光学器材目前还没有在刑事技术工作中普及.1995年初,公安部第二研究所制出可以方便的装在照相机镜头前使用的定向反射镜,我们及时引用了这一新器材,并在多起办案实践中发挥了重要作用. The use of vertically-directed reflected light to display weak contrast fingerprints on smooth objects and potential sweat fingerprints is a frequently used method of extracting fingerprints from photographs. However, the production of vertically-directed reflected light requires specialized optical equipment, which is expensive due to various aspects such as price, practicality, etc. The reason is that this optical equipment is not yet universal in criminal technology work .1995 early in the second Institute of the Ministry of Public Security can be easily installed in the camera lens before the use of directional mirrors, we promptly cited the new equipment, And played an important role in many cases handling the case.