| 摘要 |
PURPOSE:To prevent a crack from occurring as well as to aim at improvements in yield and reliability in life performance, by setting length of a part, where a core of a light emitting tube with a tungsten core of less than 0.8mm in core diameter enters a sealing part, down to a range of 2-4mm. CONSTITUTION:Each length of electrode cores 3 and 3a entering collapsed sealing parts 6 and 6a of a pair of electrodes 2 and 2a inclusive of thallium inside a light emitting tube 1 and less than 0.8mm in diameter D of these cores 3 and 3a is set down to a range of 2-4mm, and each terminal of these cores 3 and 3a at the side of these sealing parts 6 and 6a is chamfered in a radius of curvature of more than D/4. Thus, the length of these electrode cores 3 and 3a or these collapsed sealing parts 6 and 6a is set down to 2-4mm, whereby deformation to be produced by linear expansion of these cores 3 and 3a in which tungsten is a main component is reduced. Moreover, deformation to be produced by what the terminal of cores 3 and 3a of these sealing parts 6 and 6a is chamfered is reduced, thus a crack is preventable from occurring.
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