Illuminating system for endoscope or borescope

摘要

An optical illuminating system for endoscope or borescope has a round fiber optic bundle light guide and a non-spherical lens disposed at the distal end of the light guide. The lens has a flat front surface and a compound rear optical surface formed of a central flat circular portion of smaller diameter than the fiber optic bundle light guide, and a frustoconic surface that flares back from the central surface beyond the diameter of the fiber optic light guide. The conic portion of this lens provides an annular distribution of light, and the disc portion provides a spot distribution to fill in the center of the annular distribution. The overall distribution is thus generally flat over an angle of up to 120 degrees.