The liquid dispenser comprises a ratchet assembly, a rotor assembly, a reservoir assembly, and a drive mechanism. When the power is shut off, an auto-erased file list or a to-be-erased file list is displayed on electronic paper 108, in accordance with display setting contents set by the user before power off. The packaged semiconductor includes at least one optical access to a single or plurality of lightguides or optical fiber with single core and for multicore lightguides. The file indicates a start time, an end time, a key, and a password.