A display device for use in displaying an augmented reality image of a real-world view or a virtual reality image to a user, the display device comprising an optical waveguide having an input optical element for receiving an image and at least one output optical element for outputting the image, a projector for generating the image, the projector being physically coupled to the optical waveguide, and a projector housing containing at least some components of the projector, the projector housing being relatively moveable with respect to the optical waveguide between a relative position in which a real-world view through the waveguide in the region of the at least one output optical element is occluded and a relative position in which the real-world view through the waveguide in the region of the at least one output optical element is not occluded.