Moisture resistant electroluminescent phosphor with high initial brightness and method of making

US8298666B2 · kind B2 · utility

Assignee

• GLOBAL TUNGSTEN & POWDERS CORP. · US

Inventors

• Chen-Wen Fan · Sayre, US
• Tuan A. Dang · Sayre, US
• Joan M. Coveleskie · Sayre, US
• Frank A. Schwab · Towanda, US
• Dale E. Benjamin · Athens, US
• David C. Sheppeck · Sayre, US

Key dates

• Filing date: Jan 12, 2007
• Grant date: Oct 30, 2012
• Expiry date: Sep 30, 2028

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/2993
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

An electroluminescent (EL) phosphor is described wherein each individual phosphor particle is encapsulated in an inorganic coating, preferably aluminum oxyhydroxide. The encapsulated phosphor shows an extreme insensitivity to atmospheric moisture and suffers only minor loss of initial brightness in lamps. The method of applying the coating is a hybrid process, which involves EL phosphor particles first being coated with a thin inorganic film using an atomic layer deposition (ALD) method in a fluidized bed wherein the precursors are introduced sequentially in repeated cycles, subsequently followed by an additional coating layer applied by a chemical vapor deposition (CVD) method in which the precursors are introduced simultaneously.