| 摘要 |
PROBLEM TO BE SOLVED: To reduce or exclude deposition of dust onto a surface of a major optical device and to attain thermal dissipation by providing a light guide wall thermal resistance reduction means so as to eliminate the need for a ventilation means between inner and outer spaces. SOLUTION: A Peltier element means is provided to a light guide wall as a light guide wall thermal resistance reduction means. The Peltier element means is made up of a heat absorption side plate 14, a Peltier element 15, a heat dissipation side plate 16 and a heat sink 17. A temperature difference of about 20 deg.C is provided between both the plates by supplying power of about 10W to the Peltier element 15 and a heat flow of about 10W is absorbed from the heat absorption plate 14 (low temperature side) and a heat flow in total 20W is dissipated from the heat dissipation plate (high temperature side). Moreover, a metal material with good heat conductivity is not essential but recommended for a type of material of the light guide wall means 4. The heat absorption plate 14 substitutes the light guide wall means 4. The Peltier element 15 may be arranged at both sides. |
