Patent ID: 6832895
Filing Date: 2004-12-21
Classification: F04D,F05B

Abstract:
A light shield fan for use in exhausting air from an apparatus, said light shield fan comprising:a housing impeller part having an impeller opening; an impeller disposed in said impeller opening to exhaust air through said impeller opening from a first side of said housing impeller part to a second side of said housing impeller part; an impeller motor coupled with said impeller; wherein said impeller comprises a plurality of circumferentially arranged impeller blades; wherein said impeller blades are disposed in an overlapping arrangement as viewed from said second side so as to form a light shield to block light beams incident on said impeller from said first side; wherein said plurality of impeller blades comprises a plurality of circumferentially arranged first stage impeller blades, and a plurality of circumferentially arranged second stage impeller blades, said second stage impeller blades being disposed nearer to said second side of said impeller part than said first stage impeller blades; wherein each of said second stage impeller blades has a curved shape, and gaps are present between adjacent blades of said second stage impeller blades when viewed from said second side of said housing impeller part; wherein each of said first stage impeller blades has a flatter shape than said curved shape of said second stage impeller blades; and wherein, as viewed from said second side of said housing impeller part, each of said first stage impeller blades is arranged to overlap with both blades of an adjacent pair of said second stage impeller blades so as to cover said gaps and thereby block light beams incident upon said impeller from said first side of said housing impeller part.