Patent ID: 7052139

Claim:
An illumination unit, comprising: an ellipsoidal reflector having a first focus and a second focus; an arc tube having a light emitting portion in the vicinity of the first focus; a collimating lens to convert a light from the ellipsoidal reflector into a roughly parallel illumination luminous flux, a light incident surface of the collimating lens being situated at a position which is such that an area with an extremely small incident light intensity is present at a central part of the light incident surface of the collimating lens; and a first lens array having a plurality of small lenses to split the illumination luminous flux from the collimating lens into a plurality of partial luminous fluxes, the partial luminous fluxes from the first lens array being superimposed at the illuminated area respectively, a light incident surface of the first lens array being situated at a position which is closer to the ellipsoidal reflector than the second focus, and which is such that an area with an extremely small incident light intensity is not present at a central part of the light incident surface of the first lens array.