Abstract: A fiberoptic bundle or liquid light guide for a borescope, fiberscope or videoscope is coupled to the light source using a light guide coupler having a plurality of air passages to vent excess heat. The illumination unit comprises a fan that draws cool air through the passages into the light source to remove excess heat from the light guide coupler. Heat radiators can be added to the coupler to increase its surface area and to improve heat dissipation. Air baffles can be added to optimize the air flow through the light guide coupler. The light guide coupler thus acts as a heat sink while dissipating excess heat using an air flow caused by the difference in air pressure created by the fan in the illumination unit.

Abstract: A portable fiberoptic light source for use in hazardous environments includes such safety features as an aluminum housing with flame paths and cooling fins, explosion proof input connector, cable and cable plug, a shock-mounted lamp housing, a tempered heat absorbing filter, a pyrex shield and a heat shield.