| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance reliability by stably jointing a heater terminal with a base board. SOLUTION: A cathode structure is equipped with a base board 21 made of insulating material, a heater 22 made of an electroconductive material formed on one surface of the board, facial layers 23a and 23b formed on the other surface of the board 21, a base 26 for cathode provided on the surface of the facial layer 23b, and a heater terminal 27 installed at the end of the board 21 and made of a metal jointed with the heater 22, where jointing of heater terminal 27 is established via a brazing substance layer 28 formed on the surface of the heater 22 and divided in discontinuity, and the amount of expansion and contraction of the divided brazing substance layer 28 is made small to lessen the difference in expansion and contraction which originates from the difference in the thermal expansion between the material to form the heater 2 and the brazing substance layer 28, and thereby exfoliation of the layer 28 is suppressed, and jointing of the heater terminal 27 is stabilized.</p> |
