| 摘要 |
PURPOSE:To prevent dew condensation on the surface of a light emitting element and inside and outside faces of an infrared-transmissive part by constituting an inner case of a light projector with a porous body and providing a moisture permeable material on the inside of the inner case and providing heat wires around the infrared-transmissive part of an outer case and closing the outer case. CONSTITUTION:The light projector consists of an inner case 13 consisting of the porous body, a convex lens 5 supported on the inner case 13, an infrared-ray emitting diode 4 provided in the case 13, a moisture permeable fibers 15 provided in the case 13, and a closed outer case 12 where the inner case 13 is stored. Heat wire heaters 16 are provided around an infrared-transmissive filter 7 of the outer case 12. Water drops existing between the inner case 13 and the outer case 12 do not enter into the inner case 13 because of moisture permeable materials 15, and moisture in the case 13 is discharged into the case 12, and heat wire heaters 16 are operated interruptedly, thereby preventing dew condensation on the surface of the infrared-ray emitting diode 4 and the surface of the infrared-transmissive filter 7. |
