| 摘要 |
PROBLEM TO BE SOLVED: To provide a good image characteristic in the whole area of a screen by decreasing distortion according to an anti-symmetrical coma constituent of a side beam generated at a periphery of the screen. SOLUTION: A quadrupole lens is formed between grids G51, G52 and a final focusing lens is formed between grids G52, GM1 in a first lens area, and each final focusing lens is formed between grids GM1, GM2 and between grids GM2, G6 in a second and a third lens areas. The quadrupole lens does not give a function for changing a side beam orbit, and has a deflection means for generating deflection forces 1, 3 that bend side beam in a center beam direction in synchronism with deflection of an electron beam according to a deflection magnetic field in the first, the third lens areas, and has a deflection means for generating a deflection force 2 that bends the side beam in a direction reverse to the center beam direction in synchronism with deflection of an electron beam according to a deflection magnetic field in the second area, and those deflection forces have a structure to offset each other.
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