ZnS:Zn,Pb蓝粉在低压阴极射线激发下的应用

通过对ZnS:Zn,Pb蓝色荧光粉进行表面包覆SiO₂以改善其稳定性;In₂O₃材料的适量混合,提高了荧光粉的导电性,降低了它的起辉电压。采用沉淀法制备荧光屏,考察了阳极电压和阳极电流对亮度以及衰减过程的影响,实验结果表明ZnS:Zn,Pb的性能优于ZnS:Ag,Cl和ZnS:Zn,可适用于FED等低压显示器。

Application of ZnS:Zn,Pb Blue Phosphors under Low Voltage Cathode-ray Excitation

FEDdevices operate at much lower accelerating voltages,so the driving currents have to be greatly increased to maintain adequate brightness.Surface degradation of the phosphor occurs due to reaction with residual gases in the vacuum,and this is exacerbated by the higher current density.This degradation leads to decrease brightness of screen.In addition,the volatile by-products from the phosphor surface cause poisoning of the field emitter tips.Consequently,the FEDdevice ages at an accelerated rate.The low-voltage properties of ZnS:Zn,Pb were investigated for applications.Because of decomposition by irradiation of electron beam and generates of harmful gases such as SO₂ for field emitter array,the surface coating and encapsulation of phosphors is an important technique to improve low-voltages cathodoluminescence and chemical stability and to reduce outgassing.SiO₂ was used as the coating material because of its favorable band alignment when forming a heterojunction with ZnS.SiO₂ exhibits minimal losses in electron penetration and has a penetration depth nearly twice as large as that of ZnS.At low excitation voltage,the surface of ZnS:Zn,Pb gets charged because of their higher resistivity.It is necessary to reduce the resistivity of the phosphor in order to improve its low voltage cathodoluminescent properties.To lower the resistivity of the ZnS:Zn,Pb,mixing the phosphor with In₂O₃ conductive powder have been reported.The low voltage cathodoluminescent properties of this phosphors mixed with and without In₂O₃ conductive powder are studied in this investigation.When mixed with In₂O₃,the critical voltage will decrease from 80 Vto 8 V.The CLemission intensity against voltage of ZnS:Zn,Pb is more efficient than ZnS:Ag,Cl and ZnS:Zn.The blue phosphor ZnS:Zn,Pb has an excellent luminescence properties and saturation properties under high current density.It is shown that ZnS:Zn,Pb can be used as FEDphosphor.