Multi-digit fluorescent display tube with differently spaced planar control grid sections

摘要

A multi-digit fluorescent display tube is disclosed. The display tube includes a plurality of indicating patterns arranged in a row in spaced side-by-side relational along the longitudinal width of a substrate, a filament stretched along the longitudinal direction of the indicating patterns and a control grid disposed between the filament and the indicating pattern, wherein the control grid is positioned in different plane distances with respect to the filament so as to adjust the perveance in each of the indicating patterns and to obtain an uniform brightness of the indicating patterns.