In low energy electron luminescence

the electron accumulation and nonradiative recombination on the surface of phosphors is one of the main resistance in developing vacuum fluorescent display (VFD) devices. Y

2

O

2

S:Eu

ZnS:Cu

Al and ZnS:Ag are used as a kind of three-primary phosphor

excited by 400~lkeV electrons in color VFDs with the luminous efficience of R:2.61m/W

G:10.21m/W and B: 1.71m/W by 1keV excitation. In order to obtain the device with low threshold voltage and high luminous efficiency

a very thin phosphor layer is applied.To fit this three-primary phosphor for VFD

a special structure of display device is designed. This device has the following characters: (1) a tetrode structure with two layers of wire-shaped grid

so that the device can be addressed with low driving voltage by ICs; (2) a front luminous type

to widen the viewing angle; (3) a set of cathode with two spiral ends

to reduce the cold end from the length of more than 5mm to about 1mm.Based on above discussion

we developed a vacuum fluorescent display device with twelve color phosphors printed in a format of 10(column)×12(row) and operated at the anode voltage of 500V.In each column

there are 12 colors. They are pink

red

reddish orange

orange

yellowish orange

yellow

green

bluish green

blue green

greenish blue

blue and purple. This device can be used in a Hi-Fi audio system for spectrum display.