US3020803A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multifocal lens
Assignee: PPG Industries Inc
•
Filing: 1958-05-13
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Granted: 1962-02-13
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Expires: 1978-05-13
Abstract
No abstract record available.
Inventors
- 👤 James E Duncan
- 👤 Saumel L Seymour
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:16
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/04; C03C3/076; C03C3/078; C03C3/062; C03C3/07; C03C3/102; G; G02; G02C; G02C7/00; G02C7/02; G02C7/06; Y; Y10; Y10S; Y10S501/00; Y10S501/90; Y10S501/903
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
204 words
A MULTIFOCAL LENS COMPRISING A MAJOR GLASS PORTION OF THE LENS HAVING A SEGMENT GLASS PORTION FUSED THERETO, THE SEGMENT BEING COMPOSED OF A BORON-FREE AND LITHIAFREE GLASS HAVING AN INDEX OF RETRACTION, ND, BETWEEN 1.57 AND 1.67, A SOFTENING POINT ABOVE 1385*F, AND A COEFFICIENT OF THERMAL EXPANSION OF 7 TO 10X10-6 PER *C, BETWEEN 25 AND 300*C, WHICH CONSISTS ESSENTIALLY OF THE FOLLOWING INGREDIENTS IN PERCENT BY WEIGHT: 35 TO 52 PERCENT SIO2, 0 TO 12 PERCENT NA2O, O TO 10 PERCENT K2O, THE SUM OF NA2O AND K2O BEING 6 TO 12 PERCENT, 28.1 TO 34 PERCENT BAO, 2 TO 15 PERCENT ZRO2, O TO 10 PERCENT CAO, O TO 10 PERCENT ZNO AND O TO 10 PERCENT PBO, THE SUM OF CAO, ZNO AND PBO BEING 5 TO 15 PERCENT, THE ABOVE LISTED ESSENTIAL INGREDIENTS CONSTITUTING AT LEAST 95 PERCENT BY WEIGHT OF THE GLASS, AND THE MAJOR PORTION OF THE LENS BEING COMPOUND OF A CROWN GLASS HAVING AN INDEX OF REFRACTION BETWEEN 1.520 AND 1.540, A COEFFICIENT OF EXPANSION OF 7 TO 10X10-6 PER *C, BETWEEN 25 AND 300* C, AND A SOFTENING POINT WHICH IS AT LEAST 100*F, LOWER THAN THE SOFTENING POINT OF THE SEGMENT GLASS.
Claim 2
Dependent Claim
204 words
A MULTIFOCAL LENS COMPRISING A MAJOR GLASS PORTION OF THE LENS HAVING A SEGMENT GLASS PORTION FUSED THERETO, THE SEGMENT BEING COMPOSED OF A BORON-FREE AND LITHIAFREE GLASS HAVING AN INDEX OF RETRACTION, ND, BETWEEN 1.57 AND 1.67, A SOFTENING POINT ABOVE 1385*F, AND A COEFFICIENT OF THERMAL EXPANSION OF 7 TO 10X10-6 PER *C, BETWEEN 25 AND 300*C, WHICH CONSISTS ESSENTIALLY OF THE FOLLOWING INGREDIENTS IN PERCENT BY WEIGHT: 35 TO 52 PERCENT SIO2, 0 TO 12 PERCENT NA2O, O TO 10 PERCENT K2O, THE SUM OF NA2O AND K2O BEING 6 TO 12 PERCENT, 28.1 TO 34 PERCENT BAO, 2 TO 15 PERCENT ZRO2, O TO 10 PERCENT CAO, O TO 10 PERCENT ZNO AND O TO 10 PERCENT PBO, THE SUM OF CAO, ZNO AND PBO BEING 5 TO 15 PERCENT, THE ABOVE LISTED ESSENTIAL INGREDIENTS CONSTITUTING AT LEAST 95 PERCENT BY WEIGHT OF THE GLASS, AND THE MAJOR PORTION OF THE LENS BEING COMPOUND OF A CROWN GLASS HAVING AN INDEX OF REFRACTION BETWEEN 1.520 AND 1.540, A COEFFICIENT OF EXPANSION OF 7 TO 10X10-6 PER *C, BETWEEN 25 AND 300* C, AND A SOFTENING POINT WHICH IS AT LEAST 100*F, LOWER THAN THE SOFTENING POINT OF THE SEGMENT GLASS.
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) | 1965-02-12 | 1965-08-14 | 1966-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1969-02-12 | 1969-08-14 | 1970-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1973-02-12 | 1973-08-14 | 1974-02-13 | $7700.00 | Window Closed / Lapsed |