Primary mirror floating support mechanism with positioning film

The invention provides a primary mirror floating support mechanism with a positioning film and belongs to the field of primary mirror support structure of photoelectric instruments. The primary mirror floating support mechanism comprises a mandrel, a second screw, a bottom plate, the positioning film, a pin roll, a disc spring and a four-way joint, wherein the bottom plate is in an annular structure and comprises an annular boss, an annular support boss, a bottom plate central groove and a bottom plate substrate flange; a through hole is arranged in the bottom plate substrate flange, the positioning film is annular, a positioning film central groove is arranged on the inner diameter edge of the positioning film, and a positioning film annular boss is arranged on the outer diameter edge of the positioning film; the four-way joint comprises a primary mirror mounting base and a four-way round table; and a primary mirror mounting hole is formed in the primary mirror mounting base. When the ambient temperature cha