MICROWAVE DISCHARGE LIGHT SOURCE DEVICE

PURPOSE:To take out parallel light efficiently to the outside, by forming a reflection face of the light from a lamp at the inside opposed to a power supply port side in the wall of a microwave cavity, thereby eliminating loss for passing through a light transmission member and loss due to the interruption of a supporting rod. CONSTITUTION:A reflection mirror 71, which is formed on the inner surface opposite to a power supply port 5 on the surrounding wall of a light transmission member 7 or a microwave cavity 8 composed of a tubular metal mesh, is shaped into a spheri cal surface centered on a lamp 9. It may be a paraboloid, a hyperboloid or an ellipsoid and the lamp 9 is placed on the focus of the curved surface in each case. The reflection mirror is formed on the inner surface opposite to the power supply port 5 on the surrounding wall of the microwave cavity 8 where the light emitted from the lamp 9 will pass partially through the light transmission member 7 and reflected by a reflec tion plate 6 while partially reflected by the reflection mirror 71, then pass through the light transmission member 7 and reflected by the reflection plate 6 to be radiated to the outside as parallel light. Consequently, the light from the lamp 9 will pass through the light transmission member 7 not so many times and the conventional supporting rod can be eliminated. In such a manner, the light can be taken out efficient ly from the lamp and irradiate the surface to be irradiated.