Patent US3817731A successfully refreshed from Google Patents.
US3817731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of light-conducting glass fibers by vapor partial pressureatmosphere
Assignee: Nippon Selfoc Co Ltd
•
Filing: 1972-05-15
•
Granted: 1974-06-18
•
Expires: 1992-05-15
Abstract
Abstract A GLASS FIBER CONTAINING GLASS-FORMING AND GLASS-MODIFYING OXIDES IS MAINTAINED AT A TEMPERATURE ABOVE ITS STRAIN POINT AND UNDER A VACUUM FOR A CERTAIN TIME THEREBY TO HAVE THE MODIFYING OXIDE VAPORIZE OFF THE FIBER WHEREBY THE FIBER HAS SUCH A REFRACTIVE INDEX DISTRIBUTION, IN A CROSS SECTION THEREOF TRANSVERSE TO THE DIRECTION OF LIGHT ADVANCE THERETHROUGH, THAT THE REFRACTIVE INDEX DECREASES CONTINUOUSLY FROM THE CENTER TOWARD THE OTHER PERIPHERY OF THE CROSS SECTION.
Inventors
- 👤 M Yoshiyagawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:19
CPC Classifications
C; C03; C03C; C03C25/00; C03C25/002; C03B; C03B37/00; C03B37/10; C03B37/14; C03B37/15; C03C13/00; C03C13/04; C03C13/045; C03C13/046; G; G02; G02B; G02B6/00; G02B6/02; G02B6/028; G02B6/0281
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |