Optical engine and projection device

Disclosed is an optical engine, comprising a light source generator for providing light beams; a first sub-flat board light divider for dividing light beams into first reflective deviant-vibrant beams and second permeating deviant-vibrant beams; a first deviant rotator for allowing second deviant-vibrant beams to permeate through and be converted into first deviant-vibrant beams; a second sub-flat board light divider for reflecting the first deviant-vibrant beams; a main flat board light divider for reflecting the first deviant-vibrant beams reflected by the second sub-flat board light divider and converted by the first deviant rotator; and a light valve for converting the first deviant-vibrant beams reflected by the main flat board light divider into image beams to permeate therethrough. The invention is characterized by using the deviant rotator to convert the second deviant-vibrant light beams into first deviant-vibrant light beams having an identical phrase, in order to be reflected to the main flat light