| 摘要 |
PURPOSE:To obtain a stem in which a stage section is fixed rigidly and securely and no glass bubble is formed and no glass flow out onto an eyelet surface is obtained by using a glass with higher melting point for a blind hole than that of a glass for a through hole. CONSTITUTION:When an eyelet 30, a stage section 36, with a lead wire 38 and a fixing pin 40, and glass 44, 46 are assembled in a jig, and temperature in a furnace is increased, the glass 44 with lower melting point melts first and starts to wet the inner wall of a through hole 42. Then the furnace temperature is increased further, the glass 44 is so melted that the inner wall of the through hole 42 is enough wetted. But the glass 46 is first started to melt at this temperature and wets the inner wall of a blind hole 45 with the condition of high viscosity. In this condition, as the gas contained in a space section between lower part of the blind hole 45 and the glass 46 is restrain within a low expansion state because of a narrow temperature renge, the gas does not go into the glass 46 to become bubble, nor the glass 46 flow out from bling hole. |
