Patent US3920463A successfully refreshed from Google Patents.
US3920463A
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US
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Process for changing the tint of a photochromic material and material formed thereby
Assignee: Individual
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Filing: 1974-02-01
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Granted: 1975-11-18
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Expires: 1994-02-01
Abstract
Abstract The tint of a photochromic material is changed without degradation in photochromic properties by heating the material in a reducing atmosphere and, while the photochromic material is at an elevated temperature, irradiating it with ultraviolet irradiation. While the heating in a reducing atmosphere itself causes a change in the tint of the photochromic material, the subsequent ultraviolet irradiation further emphasizes this change, generally yielding darker and deeper tints. The resulting material is also described.
Inventors
- 👤 Robert A Simms
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:49
CPC Classifications
C; C03; C03C; C03C23/00; C03C4/00; C03C4/04; C03C4/06
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
129 words
A PROCESS FOR PERMANENTLY CHANGING THE TINT OF A PHOTOCHROMIC INORGANIC BORE SILICATE GLASS ARTICLE CONTAINING SUBMICROSCOPIC PARTICLES OF SILVER HALIDE, WHITOUT ADVERSE EFFECT ON THE PHOTOCHROMIC PROPERTIES THEREOF, WHICH COMPRISES HEATING THE PHOTOCHROMIC GLASS ARTICLE AT A TEMPERATURE OF AT LEAST ABOUT 300*C TO ABOUT 600*C FOR FROM ABOUT 4 MINUTES TO ABOUT 15 MINUTES IN A GASEOUS REDUCING ATMOSPHERE HAVING A FREE ENERGY OF FORMATION GREATER THAN ABOUT 1 1/2 TO ABOUT 2 ELECTROON VOLTS; AND THEN PRIOR TO SUBSTANTIAL COOLING OF SAID ARTICLE SUBJECTING SAID ARTICLE WHILE AT AN ELEVATED-TEMPERATURE TO ULTRAVIOLET IRRADIATION. SAID HEATING IN A GASEOUS REDUCING ATMOSPHERE IMPARTING AN INITIAL TINT TO THE PHOTOCHROMIC ARTICLE AND SAI SUBJECTING TO ULTRAVIOLET IRRADIATION BEING AT A TIME AND TEMPERATURE SUFFICIENT TO DEEPEN SAID INITIAL TINT.
Claim 2
Dependent Claim
129 words
A PROCESS FOR PERMANENTLY CHANGING THE TINT OF A PHOTOCHROMIC INORGANIC BORE SILICATE GLASS ARTICLE CONTAINING SUBMICROSCOPIC PARTICLES OF SILVER HALIDE, WHITOUT ADVERSE EFFECT ON THE PHOTOCHROMIC PROPERTIES THEREOF, WHICH COMPRISES HEATING THE PHOTOCHROMIC GLASS ARTICLE AT A TEMPERATURE OF AT LEAST ABOUT 300*C TO ABOUT 600*C FOR FROM ABOUT 4 MINUTES TO ABOUT 15 MINUTES IN A GASEOUS REDUCING ATMOSPHERE HAVING A FREE ENERGY OF FORMATION GREATER THAN ABOUT 1 1/2 TO ABOUT 2 ELECTROON VOLTS; AND THEN PRIOR TO SUBSTANTIAL COOLING OF SAID ARTICLE SUBJECTING SAID ARTICLE WHILE AT AN ELEVATED-TEMPERATURE TO ULTRAVIOLET IRRADIATION. SAID HEATING IN A GASEOUS REDUCING ATMOSPHERE IMPARTING AN INITIAL TINT TO THE PHOTOCHROMIC ARTICLE AND SAI SUBJECTING TO ULTRAVIOLET IRRADIATION BEING AT A TIME AND TEMPERATURE SUFFICIENT TO DEEPEN SAID INITIAL TINT.
Claim 3
Dependent Claim
11 words
The process of claim 1, wherein the reducing atmosphere comprises hydrogen.
Claim 4
Dependent Claim
15 words
The process of claim 2, wherein the reducing atmosphere further comprises an inert carrier gas.
Claim 5
Dependent Claim
12 words
The process of claim 3, wherein the inert carrier gas is nitrogen.
Claim 6
Dependent Claim
26 words
The process of claim 1, wherein said article is subjected to ultraviolet irradiation prior to substantial cooling and while said elevated temperature is above about 300*C..
Claim 7
Dependent Claim
13 words
The process of claim 5, wherein said elevated temperature is below about 600*C..
Claim 8
Dependent Claim
19 words
The process of claim 6, wherein said ultraviolet irradiation is of an intensity of at least about 100 milliwatts/cm2.
Claim 9
Dependent Claim
18 words
The process of claim 5, wherein said article is subjected to ultraviolet irradiation while naturally cooling in air.
Claim 10
Dependent Claim
18 words
The process of claim 5, wherein said ultraviolet irradiation has a wavelength of less than about 3,600 A.
Claim 11
Dependent Claim
10 words
A photochromic article produced by the process of claim 1.
Claim 12
Dependent Claim
18 words
The process of claim 7, wherein said ultraviolet irradiation has a wavelength of less than about 3,600 A.
Claim 13
Dependent Claim
20 words
The process of claim 5, wherein said ultraviolet irradiation has a wavelength in the range of 1,800 to 3,600 A.
Claim 14
Dependent Claim
20 words
The process of claim 9, wherein said ultraviolet irradiation has a wavelength in the range of 1,800 to 3,600 A.
Claim 15
Dependent Claim
14 words
The process of claim 12, wherein ultraviolet irradiation is completed within about 10 minutes.
Claim 16
Dependent Claim
14 words
The process of claim 13, wherein ultraviolet irradiation is completed within about 10 minutes.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |