The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 05, 1978
Filed:
Mar. 31, 1976
Robert A Hedler, Seneca Falls, NY (US);
GTE Sylvania Incorporated, Stamford, CT (US);
Abstract
A pigmented phosphor comprises a core of a phosphor particle having a light modifying layer thereon. The light modifying layer is comprised of a co-precipitated mixture of silica or pyrophosphate and a pigment which modifies the light output of the energized phosphor. The phosphor is coated by first preparing an unique pigment stock suspension containing the pigment, water, and a polyacrylamide dispersant. The stock solution is then diluted and phosphor particles are added thereto and the mixture is vigorously stirred. The pH of the mixture can be adjusted to about 5 by the addition of acetic acid and then a small amount of positively charged colloidal silica or pyrophosphate is added. After mixing, the pH is raised to about 9 by the addition of a base or a salt which causes a gel to form and the silica or pyrophosphate and the pigment to co-precipitate out upon the phosphor particles.