US 5,080,928 A · Method for making moisture insensitive zinc sulfide based luminescent materials

Abstract

A process is disclosed for coating phosphors with hydrolyzed alkylaluminum. The hydrolyzed alkylaluminum coating renders the phosphors insensitive to atmospheric moisture. the coating process involves vaporizing an aluminum-containing precursor such as trimethylaluminum or triethylaluminum in an inert gas stream and passing this through a fluidized bed containing the phosphor particles. Water vapor is also passed through the fluidized bed and the water and aluminum precursor react on the surface of the phosphor particles to form hydrolyzed trimethylaluminum or other alkylaluminum. The hydrolyzed trimethylaluminum or other alkylaluminum phosphors are particularly useful in electroluminescent lamps.

Claims7

Dependent claims

A method for forming a continuous coating of on phosphor particles comprising:

a) vaporizing trimethyl aluminum in a carrier gas to form a carrier gas containing vaporized trimethyl aluminum;
b) vaporizing water in a carrier gas to form a carrier gas containing vaporized water;
c) passing said carrier gas containing vaporized trimethyl aluminum and said carrier gas containing vaporized water through a finely divided phosphor powder in which phosphor particles are suspended in the carrier gases and to envelop the fluidized particles in said carrier gas containing vaporized trimethyl aluminum and said carrier gas containing vaporized water;
and
d) reacting the vaporized trimethyl aluminum and the vaporized water on the particles of the phosphor powder to form a continuous coating comprising hydrolyzed trimethyl aluminum of predetermined thickness on the phosphor particles.

2 more elements

Dependencies are inferred from the claim text.

Method for making moisture insensitive zinc sulfide based luminescent materials

Life of this patent

Method for making moisture insensitive zinc sulfide based luminescent materials

Life of this patent

Abstract

Claims7