Observation apparatus

An apparatus comprising:

• a display element configured to emit display light to display an image;
• and
• an optical system configured to guide to an exit pupil the display light and external light as light from an outside of the apparatus,
• wherein the optical system includes:
• a first polarization separating element;
• a first optical unit that includes a reflective surface and has a power for incident light;
• and
• a second optical unit that includes a half-transmissive reflective surface, a phase plate, and a second polarization separating element,
• wherein the optical system causes the external light to transmit through the first polarization separating element and the second optical unit and to travel to the exit pupil,
• wherein the optical system causes the display light to transmit through the first polarization separating element, to be reflected by the first optical unit and the first polarization separating element, to be twice reflected by the second optical unit, and to travel to the exit pupil, and
• wherein the optical system causes the display light to form an intermediate image in an optical path from the first optical unit to the second optical unit.