Patent ID: 7016393

Claim:
An illumination apparatus for projecting a line of light, comprising; a plurality of diode-lasers each thereof having an emitting-aperture and arranged in an elongated linear array thereof, said diode-lasers being spaced apart by a spacing defined as the distance between the centers of adjacent ones thereof; said linear diode-laser array having a slow axis parallel to the length direction thereof, and a fast axis perpendicular to said slow axis, light being emitted from each of said diode-lasers, from an emitting aperture thereof, as a beam including diverging rays in both said fast and slow axes, in a general direction of propagation mutually perpendicular to both said fast and slow axes; an optical system, said optical system having a longitudinal axis parallel to the propagation direction of light from said diode-lasers and having mutually perpendicular fast and slow axes corresponding to said fast and slow axes of said diode-lasers; said optical system having a plurality of components including a first lens having positive optical power in said fast axis and zero optical power in said slow axis, a linear array of cylindrical microlenses, one corresponding to each of said diode-lasers, said microlenses having a slow-axis spacing equal to the spacing of said diode-lasers in said diode-laser array, each microlens having positive optical power in said slow axis and zero optical power in said fast axis, and said microlens array having a front focal plane and a back focal plane; said microlens array being located at a distance from said emitters of said diode-lasers greater than the focal length of lenses in said microlens array but sufficiently closes to said emitters of said diode-lasers that each microlens receives light from only a said diode-laser corresponding thereto, wherein said optical system components further include a second lens having negative optical power in said fast axis and zero optical power in said slow axis, a third lens having positive optical power in both said slow axis and said fast axis, said third lens having a front focal plane and a back focal plane, and a fourth lens having positive optical power in said fast axis and zero optical power in said slow axis, said optical components being listed in order of location along the direction of propagation of light from the diode-lasers; and wherein said optical system components are selected and arranged to form overlapping elongated images in a predetermined plane, said images being elongated images of cross-sections of said beams from said diode-lasers at a plane corresponding to said front focal plane of said microlens array.