Optical fingerprint acquisition device

PURPOSE: An optical fingerprint input device is provided to minimize an optical system by installing an optical ray path conversion mirror outside a prism so that it can be applied at a small sized device, for example, a mouse or a notebook computer. CONSTITUTION: The device comprises a prism(10), the first mirror(30), the second mirror(40), and a focus lens(50). The prism(10) includes a fingerprint contact surface(11), a fingerprint contact facing surface(12), the first light exiting/second incidence surface(13), a final light exiting surface(14). The fingerprint contact surface(11) contacts with a fingerprint of a person. The fingerprint contact facing surface(12) is formed opposite to the fingerprint contact surface(11). The first light exiting/second incidence surface(13), meeting the fingerprint contact surface(11) at an angle of theta 1 and the fingerprint contact facing surface(12) at an angle of theta 2, lets a fingerprint reflection light firstly exit and be incident from the second mirror(40). The final light exiting surface(14), meeting the fingerprint contact surface(11) at an angle of theta 3, lets the fingerprint reflection light be incident from the first light exiting/second incidence surface(13). The first mirror(30) receives the fingerprint reflection light exiting from the first light exiting/second incidence surface(13), and reflects the fingerprint reflection light toward the second mirror(40). The focus lens(50) collects the fingerprint reflection light exiting from the final light exiting surface(14).