Patent ID: 7029122

Claim:
A projector having an optical system comprising: a light source, color-separation mirrors for color-separating light from the light source into a plurality of color light beams, a plurality of modulation means for modulating the respective color light beams color-separated by the color-separation mirrors, a prism for compositing the color light beams modulated by the modulation means, a projection means for projecting light composited by the prism, a cooling fan for cooling at least the modulation means, wherein the cooling fan is disposed such that a direction of cooling air is approximately parallel with long sides of the modulation means, and a circuit board disposed along a linear path of cooling air sent from the cooling fan, whereby the cooling fan cools the circuit board as well as the modulation means, wherein each of the modulation means is formed substantially in the shape of a rectangle with its aspect ratio set to be n:1 (n>1.6), and short sides of the modulation means are disposed to be substantially parallel with a plane including principal light beams of the respective color light beams to be composited by the prism.