An ellipsoidal mirror is a gyro formed after a part of an ellipse line rotates around the central axis. The light source is placed at the first focal point F1 of the ellipsoidal reflector, and after the light is reflected by the reflector, it converges at the second focal point F2 of the ellipsoidal reflector. The main function of the ellipsoidal reflector is to improve the efficiency of light source utilization. The ellipsoidal mirror substrate is made of borosilicate glass, and the surface can be coated with cooling light film, ultraviolet reflective film, protective aluminum and other thin films. HB Optical provides ellipsoidal mirrors with various focal lengths ranging from 50 to 600mm.