LIGHT DRIVING SEMICONDUCTOR DEVICE

PURPOSE:To get a light driving type thyristor that the work such as assembling, inspection, etc., can be done easily by putting the inside diameter of an inner metallic tube in two stages, and making the inside diameter of the part to be fused with an phototransmissive path by glass small, and making the inside diameter of other part large. CONSTITUTION:An inner metallic tube 82 is made of the two parts of a part 82a small in diameter and a part 82b large in diameter, and with a phototransmissive path 9, it is fused at the part 82a small in diameter by low melting point glass. Hereupon, it is made coaxial with the phototransmissive path 9 and an outer metallic tube 81, on the other hand, the outer metallic tube 81 and the inner metallic tube 82 are welded with an envelop uniformly in the positions separate in outside diameter direction, so the inside of the outer metallic tube 81 and the outside of the inner metallic tube 82 can be set with each other without backlash.