| 摘要 |
PURPOSE:To maintain the distance between a mesh electrode and a target constant with high accuracy by suppressing the distance between a face plate and the end surface of a glass valve to be constant by providing projections on the inner circumference of a holding ring. CONSTITUTION:Three or four projections 11 are provided on the inner circumference of a holding ring 10 at 120 deg. or 90 deg. spacings, respectively. After that, an indium 12 is stuck over the ring 10 and the projections 11 so as to make an indium ring 13. The dimension (l3) of the projections 11 is made to correspond to the distance between a face plate 1 and the end surface of a glass valve 2. By the means mentioned above, the distance between a mesh electrode and a target can be maintained constant with high accuracy. Consequently, variations in such characteristics as shading, framing and the like which are influenced by the landing of electron beams upon the target can be suppressed. |
