The disclosure relates to an optical system for an augmented reality apparatus, comprising: an image projection source; and a polarizing beam splitter. The polarizing beam splitter has a beam splitting side adjacent to the image projection source and a transmission side facing away from the image projection source. The polarizing beam splitter is arranged such that light emitted from the image projection source is able to be non-perpendicularly incident on the beam splitting side and be at least partially reflected. The polarizing beam splitter is configured such that when light is incident on the beam splitting side, a polarized light component passes through the polarizing beam splitter and is transmitted through the transmission side thereof, and a polarized light component is reflected from the beam splitting side. The optical system also comprises a polarizer disposed between the image projection source and the beam splitting side of the polarizing beam splitter.