Patent ID: 6238052
Filing Date: 2001-05-29
Classification: G02B

Abstract:
A fogless mirror which is resistant to condensation fogging of water vapor on optical surfaces thereof comprising;a. a ring-shaped frame,b. a front viewing window mounted in said frame in a fluid pressure-tight seal therewith;c. a rear reflective mirror plate mounted in said frame in a fluid pressure-tight seal therewith at a location spaced rearward of said front viewing window forming between inner facing surfaces of said mirror plate and said window a sealed interior space bordered on a peripheral longitudinal surface thereof by an inner annular surface of said frame,d. means for filling said sealed interior space with water to thereby form a plenum, said water within said plenum contacting inner facing surfaces of said window and said mirror plate adjacent to said plenum and thereby precluding condensation fogging on said inner facing surfaces,e. means for maintaining said water within said plenum at a temperature above ambient air temperature, andf. means for conducting heat from said water within said plenum to a front, outer surface of said viewing window, thereby resisting condensation fogging on said front outer surface of said window.