US3873408A
Expired / Lapsed
US
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Method of producing a refractive index gradient in glass
Assignee: Bausch and Lomb Inc
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Filing: 1972-11-09
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Granted: 1975-03-25
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Expires: 1992-11-09
Abstract
Abstract Method of increasing the refractive index of a surface layer of an alkali-silicate glass by diffusing ions of silver, thallium, copper, or combinations thereof into the glass at temperatures of about 800* to about 1,100*F. for at least about one hour. The resulting increase of the refractive index is graded, being greatest at the surface, and decreasing approximately uniformly as a function of depth. Penetrations of about 0.3 to about 10 mm. are shown. Stable salts such as the chlorides are used as source materials for the ions.
Inventors
- 👤 Joseph R Hensler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:54
CPC Classifications
C; C03; C03C; C03C21/00; C03C21/001; C03C21/005; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/26; Y10T428/268
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
115 words
METHOD OF INCREASING THE REFRACTIVE INDEX OF A SURFACE LAYER OF PREDETERMINED DEPTH OF A GLASS BODY CONSISTING ESSENTIALLY OF, BY WEIGHT, BATCH BASIS, 51% TO 71% SILICA, UP TO 26% ALUMINA, 7% TO 35% SODA, UP TO 15% POTASH, UP TO 10% LIME, UP TO 6% MAGNESIA, AND UP TO 6% BORIC AICD, ANHYDROUS BASIS COMPRISING THE STEP OF MAINTAINING THE BODY IN CONTACT WITH A MOLTEN SOURCE OF IONS FOR AT LEAST 1 HOUR AT A TEMPERATURE BETWEEN 800*F. AND 1.100*F., THE IONS BEING SELECTED FROM THE GROUP CONSISTING OF SILVER, THALLIUM, AND COPPER IONS, AND MIXTURES THEREOF, THEREBY TO CAUSE THE SELECTED IONS TO DIFFUSE INTO THE BODY TO THE PREDETERMINED DEPTH.
Claim 2
Dependent Claim
115 words
METHOD OF INCREASING THE REFRACTIVE INDEX OF A SURFACE LAYER OF PREDETERMINED DEPTH OF A GLASS BODY CONSISTING ESSENTIALLY OF, BY WEIGHT, BATCH BASIS, 51% TO 71% SILICA, UP TO 26% ALUMINA, 7% TO 35% SODA, UP TO 15% POTASH, UP TO 10% LIME, UP TO 6% MAGNESIA, AND UP TO 6% BORIC AICD, ANHYDROUS BASIS COMPRISING THE STEP OF MAINTAINING THE BODY IN CONTACT WITH A MOLTEN SOURCE OF IONS FOR AT LEAST 1 HOUR AT A TEMPERATURE BETWEEN 800*F. AND 1.100*F., THE IONS BEING SELECTED FROM THE GROUP CONSISTING OF SILVER, THALLIUM, AND COPPER IONS, AND MIXTURES THEREOF, THEREBY TO CAUSE THE SELECTED IONS TO DIFFUSE INTO THE BODY TO THE PREDETERMINED DEPTH.
Claim 3
Dependent Claim
27 words
Method according to claim 1 wherein the glass body is substantially free of arsenic, whereby the diffused ions do not introduce significant color into the surface layer.
Claim 4
Dependent Claim
13 words
Method according to claim 1 wherein the molten source is a stable salt.
Claim 5
Dependent Claim
29 words
Method according to claim 1 wherein the molten source consists essentially of a substance selected from the group consisting of silver chloride, thallium chloride, copper chloride, and mixtures thereof.
Claim 6
Dependent Claim
85 words
Method of increasing the refractive index of a surface layer at least about 0.4 mm. thick of a body of glass consisting essentially of, by weight, batch basis, 51% to 71% silica, up to 26% alumina, 7% to 35% soda, up to 15% potash, up to 10% lime, up to 6% magnesia, and up to 6% boric acid, anhydrous basis comprising the step of maintaining the body in contact with molten silver chloride at a temperature of at least 920*F. for at least one hour.
Claim 7
Dependent Claim
85 words
Method of increasing the refractive index of a surface layer at least about 0.4 mm. thick of a body of glass consisting essentially of, by weight, batch basis, 51% to 71% silica, up to 26% alumina, 7% to 35% soda, up to 15% potash, up to 10% lime, up to 6% magnesia, and up to 6% boric acid, anhydrous basis comprising the step of maintaining the body in contact with molten silver chloride at a temperature of at least 920*F. for at least one hour.
Claim 8
Dependent Claim
123 words
A glass body having a zone adjacent to a surface thereof and at least about 0.3 mm. thick in which the refractive index is higher than the refractive index of the bulk of the body and varies as a function of distance from the surface being highest at the surface, the bulk of said body consisting essentially of, by weight, batch basis, 51% to 71% silica, up to 26% alumina, 7% to 35% soda, up to 15% potash, up to 10% lime, up to 6% magnesia, and up to 6% boric acid, anhydrous basis, and said zone including ions selected from the group consisting of silver, thallium, and copper ions, and mixtures thereof, the concentration of said ions being greatest at the surface.
Claim 9
Dependent Claim
123 words
A glass body having a zone adjacent to a surface thereof and at least about 0.3 mm. thick in which the refractive index is higher than the refractive index of the bulk of the body and varies as a function of distance from the surface being highest at the surface, the bulk of said body consisting essentially of, by weight, batch basis, 51% to 71% silica, up to 26% alumina, 7% to 35% soda, up to 15% potash, up to 10% lime, up to 6% magnesia, and up to 6% boric acid, anhydrous basis, and said zone including ions selected from the group consisting of silver, thallium, and copper ions, and mixtures thereof, the concentration of said ions being greatest at the surface.
Claim 10
Dependent Claim
111 words
A glass body having a zone adjacent to a surface thereof and at least about 0.3 mm. thick in which the refractive index is higher than the refractive index of the bulk of the body and varies as a function of distance from the surface being highest at the surface, the bulk of said body consisting essentially of, by weight, batch basis, 51% to 71% silica, up to 26% alumina, 7% to 35% soda, up to 15% potach, up to 10% lime, up to 6% magnesia, and up to 6% boric acid, anhydrous basis, and said zone including ions of silver, the concentration of said ions being greatest at the surface.
Claim 11
Dependent Claim
111 words
A glass body having a zone adjacent to a surface thereof and at least about 0.3 mm. thick in which the refractive index is higher than the refractive index of the bulk of the body and varies as a function of distance from the surface being highest at the surface, the bulk of said body consisting essentially of, by weight, batch basis, 51% to 71% silica, up to 26% alumina, 7% to 35% soda, up to 15% potach, up to 10% lime, up to 6% magnesia, and up to 6% boric acid, anhydrous basis, and said zone including ions of silver, the concentration of said ions being greatest at the surface.
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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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |