Method of producing light-absorbing edging about phosphor dots on color image screens

DETAILED DESCRIPTION The invention provides a method of producing light-absorbing, preferably black-colored, edging or matrix, which may be electrically conductive, about phosphor dots on image screen substrates, particularly on flat color screen substrates.
In accordance with the principles of the invention, a glass screen substrate is coated on a surface thereof with a uniform photoformable layer comprised of a slurry containing particles of glass-forming substances and, optionally, particles of metal oxides, dispersed in a photolacquer.
The so-applied layer is developed in accordance with conventional photoform techniques so that windows are formed in such layer for color phosphor dots to be applied later.
A tempering or heating process is undertaken, either prior to or after application of the phosphor dots, at a temperature in the range of about 350.
degree.
C.
to 500.
degree.
C.
In certain embodiments of the invention, the slurry is comprised of a mixture of a glass solder powder and a material selected from the group consisting of metal oxides, organo-metallic compounds, silicon esters e.
g.
tetraacetoxysilane and mixture thereof, dispersed in a photolacquer.
In other embodiments, particularly where thinner layers are desired, the slurry may be comprised of organo-metallic compounds and silicon esters dispersed in a photolacquer.
Exemplary organo-metallic compounds comprise sulfur resinates, mercaptans and carboxylates of Ni, Co, Pb, Pt and Au.
Sulfur resinates may be obtained, for example, by boiling a select metal salt in sulfonated oil of terpentine e.
g.
gold-tert-dodecyl-mercaptide.
These compounds disintegrate at temperatures above about 250.
degree.
C.
and, depending on the oxidation behavior of the particular element, the metals per se or their oxides are formed.
By adding a small amount of a noble metal (i.
e.
, Au or Pt) resinate to a non-noble metal (i.
e.
, Ni or Pb) resinate, a certain conductivity in the light-absorbing layer can be obtained, even when such resinate mixture is heated or tempered in an oxidizing atmosphere, for example air