| 摘要 |
PROBLEM TO BE SOLVED: To ensure the seal between a diaphragm and a case and attain the miniaturization and improvement in reliability by directly fixing a diaphragm presser member serving as a middle lid to a plastic case. SOLUTION: A diaphragm presser member 11 is fixed to a plastic case 1 in a position 12 by ultrasonic welding, whereby a diaphragm 2 consisting of a gas permeable porous plastic film is pressed onto the plastic case 1. Thereafter, the plastic case 1 is adhered or welded in a position 13 to complete a gas sensor. A working electrode 6 consisting of noble metal catalyst is placed in contact with the diaphragm 2, and a counter electrode 9 and a reference electrode 10 are arranged on the opposite side to the working electrode 6 with an electrolyte holding body 7 holding an electrolyte 8 between. To directly fix the diaphragm presser member 11 to the plastic case 1, various welding methods such as laser welding can be used. When an adhesive material is used for both of them, the both may be fixed by adhesion by use of an adhesive. In this case, it is necessary to consider the poisoning of the noble metal catalyst by the organic solvent used in the adhesive. |
