VIDEO PROJECTION APPARATUS CAPABLE OF REALIZING STABLE ROCKING ANGLE AT OPTIMUM RESONANT FREQUENCY

摘要

A video projection apparatus includes: an optical deflector (19) having a mirror (191) projecting a first view field (F1) and projecting a second view field (F2), an actuator (193a) for rocking the mirror (191) and a sensor (197a); an optical guide unit (25) provided within the second view field (F2); a photodetector (26) ; and a control unit (14, 15, 16). The control unit (14, 15, 16) is adapted to calculate a resonant frequency (f r ) of the sinusoidal-wave voltage (V xa ) ; detect a first stiming point (t0) from a sense voltage (V xs ) detect a second timing point (t1, t2, t3) from a photo detection voltage (V pd ) when the second light beam (L2) is incident to the optical guide unit (25); calculate a time, period (T) from the first timing point (t0) to the second timing point (t1); calculate a product value (P) between the time period (T) and the resonant frequency (f r ) ; and control an amplitude (A) of the sinusoidal-wave voltage (V xa ).