US3997249A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ion exchangeable segment glass
Assignee: American Optical Corp
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Filing: 1975-10-28
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Granted: 1976-12-14
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Expires: 1995-10-28
Abstract
Abstract There is disclosed an ion exchange-strengthened ophthalmic segment glass suitable for the fabrication of fused bifocal and trifocal ophthalmic lenses. More particularly, there is disclosed a lanthanum-silicate based ophthalmic segment glass having indices of refraction of about 1.57 to about 1.65 which is suitable for chemical ion exchange strengthening so as to develop a compressively-stressed ion-exchanged surface layer having a depth of at least 60 micrometers.
Inventors
- 👤 David A. Krohn
- 👤 Robert E. Graf
- 👤 Emil W. Deeg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:48
CPC Classifications
C; C03; C03C; C03C21/00; C03C3/00; C03C3/04; C03C3/076; C03C3/095; G; G02; G02C; G02C7/00; G02C7/02; G02C7/06; Y; Y10; Y10S; Y10S501/00; Y10S501/90; Y10S501/903; Y10T; Y10T428/00; Y10T428/31; Y10T428/315
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
142 words
A chemically ion exchange-strengthened lanthanum-silicate based ophthalmic segment glass having a compressively-stressed, ion-exchanged surface zone that is at least 60 micrometers in depth, said glass being formed of a lanthanum-silicate glass consisting essentially of alkali metal oxides selected from the group consisting of (1) mixtures of sodium and potassium oxides and (2) mixtures of the oxides of sodium and potassium and other alkali metal oxides wherein said alkali metal oxides are present in the proportions by weight: ______________________________________
sodium oxide about 7 to about 10 percent
potassium oxide
about 8 to about 12 percent
other alkali
metal oxides up to 5 percent
______________________________________ provided the proportion of total alkali metal oxides present is up to 20 percent, in combination with about 15 to about 35 percent lanthanum oxide; the balance of said glass being essentially about 30 to about 60 percent silica.
Claim 2
Dependent Claim
142 words
A chemically ion exchange-strengthened lanthanum-silicate based ophthalmic segment glass having a compressively-stressed, ion-exchanged surface zone that is at least 60 micrometers in depth, said glass being formed of a lanthanum-silicate glass consisting essentially of alkali metal oxides selected from the group consisting of (1) mixtures of sodium and potassium oxides and (2) mixtures of the oxides of sodium and potassium and other alkali metal oxides wherein said alkali metal oxides are present in the proportions by weight: ______________________________________
sodium oxide about 7 to about 10 percent
potassium oxide
about 8 to about 12 percent
other alkali
metal oxides up to 5 percent
______________________________________ provided the proportion of total alkali metal oxides present is up to 20 percent, in combination with about 15 to about 35 percent lanthanum oxide; the balance of said glass being essentially about 30 to about 60 percent silica.
Claim 3
Dependent Claim
25 words
An ion exchange-strengthened ophthalmic segment glass in accordance with claim 1 wherein said glass comprises by weight about 20 to about 35 percent lanthanum oxide.
Claim 4
Dependent Claim
39 words
An ion exchange-strengthened lanthanum-silicate based ophthalmic segment glass according to claim 2 wherein said glass comprises by weight 10 percent potassium oxide, 9 percent sodium oxide, 7.5 percent titanium oxide, 5 percent tantalum oxide and 30 percent lanthanum oxide.
Claim 5
Dependent Claim
33 words
An ion exchange-strengthened ophthalmic segment glass according to claim 2 wherein said glass comprises by weight 10 percent potassium oxide, 9 percent sodium oxide, 30 percent lanthanum oxide and the balance silicon dioxide.
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) | 1979-12-14 | 1980-06-14 | 1980-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-12-14 | 1984-06-14 | 1984-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-12-14 | 1988-06-14 | 1988-12-14 | $7700.00 | Window Closed / Lapsed |