An optical system includes a light-guide optical element (LOE) with a pair of parallel major external surfaces for guiding image light by internal reflection and a lateral coupling-in surface. An image projector includes a prism with a first surface associated with an illumination arrangement, a second surface associated with a reflective spatial light modulator (SLM), a third surface having a quarter-wave plate and a reflective collimating lens, and a fourth surface optically coupled to the coupling-in surface of the LOE. A polarizing beam splitter (PBS) is arranged within the prism to define a light path from the illumination arrangement via the SLM and the collimating lens to the coupling-in surface of the LOE. A fifth surface of the prism forms a continuation of one of the major external surfaces of the LOE.