US3647406A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of achieving surface refractive index changes in a glass light guide element
Assignee: AT&T Inc
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Filing: 1968-11-04
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Granted: 1972-03-07
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Expires: 1988-11-04
Abstract
Abstract The surface index of refraction of a light-guiding glass is controllably increased or decreased by changing the alkali metal ion concentration at the surface. In one approach, these ions are replaced with similar ions of differing ionic radius. A gaseous source of replacement ions and capable of extracting the surface ions is passed over the glass surface at temperatures sufficient to permit an ion diffusion inward. Control of the process parameters permits regulating the exchanged ion layer depth and approximating a definite refractive index gradient, which is not possible with conventional cladding. Optical light guides achievable with the process are disclosed.
Inventors
- 👤 George M C Fisher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:57
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/36; G02B6/3608; C; C03; C03B; C03B37/00; C03B37/01; C03B37/02; C03B37/022; C03B37/023; C03B37/0235; C03C; C03C21/00; C03C21/001; C03C21/002; C03C21/007; C03C25/00; C03C25/66; C03C25/68; G02B6/02; G02B6/10; G02B6/12; G02B6/13; G02B6/134; G02B6/1345; G02B6/3628; G02B6/3632; G02B6/3636; C03B2205/00; C03B2205/50; C03B2205/52; C03B2205/54; C03B2205/55; G02B6/3616; G02B6/3624; Y; Y10; Y10T; Y10T428/00; Y10T428/31; Y10T428/315
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
27 words
Method pursuant to claim 1 wherein said sulfur dioxide flow-rate is substantially 50 cc. per minute and said water-saturated oxygen flow-rate is substantially 1,000 cc. per Minute.
Claim 2
Dependent Claim
123 words
Method for producing in a glass substrate an optical transmission channel characterized by a central region extending a preselected distance from the substrate surface inwardly, and having a refractive index that gradually increases from a first value at the substrate surface to a second constant value at a zone within the substrate core, comprising the steps of: masking out a path on the surface of a substrate having the composition Na2O-Al2O3-SiO2; and subjecting said substrate at approximately 400* C. to flowing dry sulfur dioxide gas; said sulfur dioxide inducing an outward diffusion of ions of said sodium from a region beneath the unmasked portion of said substrate; and the said outward diffusion resulting in said gradually increasing refractive index in said central region.
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) | 1975-03-07 | 1975-09-06 | 1976-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-07 | 1979-09-06 | 1980-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-07 | 1983-09-06 | 1984-03-07 | $7700.00 | Window Closed / Lapsed |