Patent ID: 6888653

Claim:
An optical scanning device, comprising: a housing having a wall defining an internal space surrounded thereby; a rotational plate provided in the internal space of the housing, the rotational plate having a rotational axis, the rotational plate being provided with an optical deflection portion deflecting an incident light beam in a predetermined direction; and a driving unit that causes the rotational plate to float in the internal space of the housing and that drives the rotational plate to rotate around its central axis, wherein the rotational plate has a first surface, the optical deflection portion being provided on the first surface, wherein the wall of the housing includes a first wall portion, the first wall portion being located at a position confronting the optical deflection portion on the first surface of the rotational plate, at least a part of the first wall portion including a light incident portion that is made from material that allows the light beam to pass therethrough, and wherein the optical deflection portion receives the light beam, which has passed through the light incident portion and which has fallen incident on the rotational plate in a direction substantially normal to the first surface, the optical deflection portion deflecting the received light beam in at least one predetermined direction along a plane substantially parallel to the first surface.