| 摘要 |
PURPOSE:To easily and surely perform the positioning work of an electron gun, by providing a plurality of windows in a same side wall of an electrode of the electron gun, reflecting a beam of light incident from one of said windows upon the inner side of the electrode and measuring the quantity of its reflecting light with through the other window. CONSTITUTION:On a same side wall 203 at one end of the third grid 2 in an electrode of an electron gun, two windows 204, 205 are provided, and through one of the windows 204 a beam 301 of light is caused incident from a light source 3 upon the inner face of another side wall at the other end of the grid and reflected, and then through the other window 205 its reflected light is received by a light sensing element 4 having a mask 5. The adjustment of an attitude for the electrode of the electron gun can be performed by correcting a position and rotating angle in every direction in such a manner that the light sensing element 4 receives a maximum quantity of light. And if another light sensing element (not shown in the drawing) is provided neighboring to the light sensing element 4 to also measure the quantity of light reflected from the vicinity of the window 204, the positioning adjustment work can be further easily performed. |
