The invention discloses a high-precision positioning device and a high-precision positioning method for a far focus of an ellipsoidal reflector. The high-precision positioning device and the high-precision positioning method belong to the field of optical
confocal microscopic technologies and optical precise measurement. The high-precision positioning device comprises a lapping
optical path which is composed of optical elements such as
laser devices, and further comprises an ellipsoidal reflector and the like. The high-precision positioning method comprises the steps of firstly, conducting effective imaging by means of an
image sensor, then adjusting a six-degree-of-freedom
workbench, acquiring a series of intensity information and roundness information of a
light spot, merging the information into an
evaluation function, establishing a degree-of-freedom and
evaluation function table, finding out an extreme value of the
evaluation function and a degree of freedom corresponding to the extreme value in the degree-of-freedom and evaluation
function table, and finally adjusting the six-degree-of-freedom
workbench according to the degree of freedom corresponding to the extreme value such that a focus of a focusing objective lens coincides with the far focus of the ellipsoidal reflector. The high-precision positioning device and the high-precision positioning method fully utilize the
special property of the bifocal conjugation of the ellipsoidal reflector, and realize precise positioning of the ellipsoidal reflector through providing a technological means for positioning the far focus of the ellipsoidal reflector by utilizing the imaging
light spot information.