Patent ID: 7843638

Claim:
An optical system comprising a first diffraction section, a second diffraction section, and a light guiding section, wherein the first diffraction section and the second diffraction section are attached to the light guiding section in a state separated from each other, the first diffraction section diffracts light flux that is incident on the first diffraction section to be incident on the light guiding section, the light guiding section guides light flux that has been diffracted by the first diffraction section to the second diffraction section using reflection or refraction inside the light guiding section, the second diffraction section re-diffracts light flux that has been guided by the light guiding section and output to outside of the light guiding section, and the first diffraction section, the light guiding section, and the second diffraction section are substantially symmetrical on either side of a virtual plane between the first diffraction section and the second diffraction section, and wherein the first diffraction section is configured to have an intermediate image plane at substantially a same position as the virtual plane by using the light flux diffracted by the first diffraction section so that the first diffraction section, the light guiding section, and the second diffraction section are substantially symmetrical on either side of the intermediate image plane.