Patent ID: 7022962

Claim:
An apparatus for determining positions, comprising: (a) a rotary laser apparatus for emitting two or more fan-shaped laser beams, said rotary laser apparatus including a laser projector and a rotary unit rotating relative to said laser projector, wherein: said laser projector has: (1) a first laser illuminator for emitting a first linearly polarized laser beam; (2) a second laser illuminator for emitting a second linearly polarized laser beam; (3) a first polarized beam splitter for directing the laser beams emitted from said first laser illuminator and said second laser illuminator in the same direction; and (4) a first one-quarter wave plate for converting said first and second linearly polarized laser beams from said first polarized beam splitter into circularly polarized laser beams; and said rotary unit has: (1) a second one-quarter wave plate for converting the circularly polarized laser beams from said first one-quarter wave plate into linearly polarized laser beams; (2) a second polarized beam splitter for splitting the linearly polarized laser beams from said second one-quarter wave plate; (3) a third one-quarter wave plate for converting the laser beams split and reflected by said second polarized beam splitter into circularly polarized laser beam; (4) a first cylinder mirror for converting the circularly polarized laser beam from said third one-quarter wave plate into a first fan-shaped laser beam and reflecting back and emitting said fan-shaped laser beam through said third one-quarter wave plate and said second polarized beam splitter; (5) a fourth one-quarter wave plate for converting laser beams transmitted through said second polarized beam splitter into a circularly polarized laser beam; and (6) a second cylinder mirror for converting said circularly polarized laser beam from said fourth one-quarter wave plate into a second fan-shaped laser beam and reflecting back and emitting said second fan-shaped laser beam through said fourth one-quarter wave plate and said second polarized beam splitter; and (b) optical sensor means for receiving the fan-shaped laser beams to determine a position.