Patent US4684540A successfully refreshed from Google Patents.
US4684540A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coated pigmented phosphors and process for producing same
Assignee: Osram Sylvania Inc
•
Filing: 1986-01-31
•
Granted: 1987-08-04
•
Expires: 2006-01-31
Abstract
Abstract A pigmented silicate coated phosphor is disclosed and a process for producing the phosphor. The process involves preparing a relatively uniform aqueous mixture of particles of a phosphor, particles of a deagglomerated pigment, and a free flowing agent and then adding a precipitating agent to the mixture in an amount sufficient to cause the free flowing agent and pigment to co-precipitate upon and coat the phosphor, followed by separating the pigmented phosphor from the resulting liquor. A relatively uniform mixture is formed of the resulting dried phosphor, a water soluble silicate, and water the water being in an amount of sufficient to allow the silicate to coat the surface of the phosphor particles. The mixture is heated at a sufficient temperature for a sufficient time with sufficient agitation to produce the final non-agglomerated silicate coated pigmented phosphor.
Inventors
- 👤 Harry O. Schulze
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:43
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/02; C09K11/025
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
161 words
A process for producing a pigmented coated phosphor, said process comprising: (a) deagglomerating a pigment; (b) preparing a relatively uniform aqueous mixture of particles of a phosphor, particles of the pigment, and a free flowing agent; (c) adding a precipitating agent to said mixture in an amount sufficient to cause said free flowing agent and said pigment to coprecipitate upon and coat said phosphor; (d) separating the resulting pigmented phosphor particles from the resulting liquor; (e) drying said pigmented phosphor particles; (f) forming a relatively uniform mixture consisting essentially of the resulting dried pigmented phosphor particles, a source of a water soluble silicate, and water, with the amount of water being sufficient only to allow the silicate to coat the surface of said phosphor particles and form a moist powder; (g) heating the resulting mixture of pigmented phosphor particles and silicate at a sufficient temperature for a sufficient time with sufficient agitation to produce the final nonagglomerated silicate coated pigmented phosphor.
Claim 2
Dependent Claim
161 words
A process for producing a pigmented coated phosphor, said process comprising: (a) deagglomerating a pigment; (b) preparing a relatively uniform aqueous mixture of particles of a phosphor, particles of the pigment, and a free flowing agent; (c) adding a precipitating agent to said mixture in an amount sufficient to cause said free flowing agent and said pigment to coprecipitate upon and coat said phosphor; (d) separating the resulting pigmented phosphor particles from the resulting liquor; (e) drying said pigmented phosphor particles; (f) forming a relatively uniform mixture consisting essentially of the resulting dried pigmented phosphor particles, a source of a water soluble silicate, and water, with the amount of water being sufficient only to allow the silicate to coat the surface of said phosphor particles and form a moist powder; (g) heating the resulting mixture of pigmented phosphor particles and silicate at a sufficient temperature for a sufficient time with sufficient agitation to produce the final nonagglomerated silicate coated pigmented phosphor.
Claim 3
Dependent Claim
15 words
A process of claim 1 wherein said free flowing agent is positively charged colloidal silica.
Claim 4
Dependent Claim
12 words
A process of claim 2 wherein said precipitating agent is a base.
Claim 5
Dependent Claim
11 words
A process of claim 3 wherein said base is ammonium hydroxide.
Claim 6
Dependent Claim
21 words
A process of claim 4 wherein the sufficient amount of base raises the pH to from about 6 to about 9.
Claim 7
Dependent Claim
45 words
A process of claim 1 wherein said aqueous mixture is prepared by the steps of: deagglomerating said pigment, forming aqueous slurries of said pigment in water and said phosphor in water and combining said slurries; and adding to the combined slurries said free flowing agent.
Claim 8
Dependent Claim
11 words
A process of claim 1 wherein said silicate is potassium silicate.
Claim 9
Dependent Claim
59 words
A process of claim 1 wherein said mixture of pigmented phosphor and silicate is heated at a temperature of about 100° C. with agitation to remove water followed by heating at a temperature of from about 400° C. to about 550° C. to dehydrate said silicate to form a water insoluble glassy film silicate coating on said pigmented phosphor.
Claim 10
Dependent Claim
9 words
A product produced by the process of claim 1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-03 | 1991-02-02 | 1991-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-03 | 1995-02-02 | 1995-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-03 | 1999-02-02 | 1999-08-04 | $7700.00 | Window Closed / Lapsed |