HIGH EFFICIENCY FIBER OPTICS ILLUMINATOR WITH THERMALLY CONTROLLED LIGHT GUIDE BUSHING

摘要

This invention applies to the field of illuminators for fiber optics and particularly for plastic fiber bundle light guides. High light levels have not been possible with prior art illuminators due to plastic fiber aging, melting and burning in the heat of concentrated light. The present invention solves the fiber heating problem through an illuminator (1) having an optical element (7) forming an image of the illumination source (2) and an image plane (5). A thermal control bushing (21) on the optical axis exit aperture includes an elongated glass rod (9) having a first end (8) at the source image plane receiving focused illumination and heat, and a second end (10) external to the housing. The thermal control bushing (21) dissipates heat from the glass rod by radiation outside the housing and by convection aided by a ventilating fan (25, 26). A fiber optics light guide (15) has a receiving end (16) adjacent to the second end of the glass rod, and a remote light-emitting end (20). In a preferred embodiment the glass rod includes a series of conjugate refocus planes (32, 32a) spaced from the image plane and has a length such that the illumination at its light emitting end (10) is substantially out of focus adjacent to the fiber optics light guide receiving end (16).