Patent ID: 9348133
Filing Date: 2016-05-24
CPC Classification: G02B

Claim Text:
1. An image projection method for controlling a microelectromechanical system (MEMS) scanning mirror to swing around a first swing axis in order to project an image light beam on a projection plane along a first direction, the image projection method comprising: measuring a resonance frequency and a damping coefficient of the MEMS scanning mirror swinging around the first swing axis; calculating a first amplitude scale and a first maintaining period according to the resonance frequency and the damping coefficient, wherein the first amplitude scale is calculated by following equation: where, α is a first ratio coefficient, ζ is a damping coefficient, and the first amplitude scale is a multiplication of the first ratio coefficient and an amplitude of the periodic wave signal; generating a periodic wave signal, wherein each time when a level of the periodic wave signal rises to the first amplitude scale, during the first maintaining period, the level of the periodic wave signal is maintained at the first amplitude scale; inputting the periodic wave signal to the MEMS scanning mirror to control the MEMS scanning mirror to swing, and recording a swing speed error of the MEMS scanning mirror; adjusting the first amplitude scale and the first maintaining period to change the periodic wave signal, and recording the corresponding swing speed error; and generating a corrected periodic wave signal to control the MEMS scanning mirror to swing according to the recorded swing speed error.