GB1413891A - Optical glass bodies - Google Patents
Optical glass bodiesInfo
- Publication number
- GB1413891A GB1413891A GB1112573A GB1112573A GB1413891A GB 1413891 A GB1413891 A GB 1413891A GB 1112573 A GB1112573 A GB 1112573A GB 1112573 A GB1112573 A GB 1112573A GB 1413891 A GB1413891 A GB 1413891A
- Authority
- GB
- United Kingdom
- Prior art keywords
- per cent
- mol per
- glass
- central axis
- concentration
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C21/00—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C13/00—Fibre or filament compositions
- C03C13/04—Fibre optics, e.g. core and clad fibre compositions
- C03C13/045—Silica-containing oxide glass compositions
- C03C13/046—Multicomponent glass compositions
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Glass Compositions (AREA)
- Surface Treatment Of Glass (AREA)
Abstract
1413891 Optical glass body having a refractive index gradient NIPPON SELFOC CO Ltd 7 March 1973 [10 March 1972 30 March 1972] 11125/73 Heading C1M An optical glass body comprises at its central axis 50-70 mol. per cent SiO 2 , 10-30 mol per cent B 2 O 3 , 1-25 mol per cent Tl 2 O, and R 2 O, wherein R is at least one of the alkali metals, in an amount of up to 29 mol per cent such that the total proportion of Tl 2 O and R 2 O is 10-30 mol per cent, and optionally other compatible ingredients, e.g. ZnO in an amount 0-12 mol per cent, the concentration of the thallium ions contained in said glass body decreasing from its central axis to the peripheral surface in such a manner that the refractive index of the glass body continuously decreases from the central axis of its body to its peripheral surface. The glass body may contain at least one of Li<SP>+</SP>, Na<SP>+</SP>, K<SP>+</SP>, Rb<SP>+</SP> and Cs<SP>+</SP> ions in a concentration which increases from the central axis of the body towards the peripheral surface thereof. The preferred refractive index distribution is parabolic satisfying the equation N=N 0 (1 - ar<SP>2</SP>) wherein N 0 is the refractive index at the central axis of the body, N is the refractive index at a distance r from the central axis of the body in a direction perpendicular to the central axis and a is a positive constant. The glass body may be produced by contacting a glass body comprising 50-70 mol per cent SiO 2 , 10-30 mol per cent B 2 O 3 , 1-25 mol per cent Tl 2 O, and R 2 O, wherein R is at least one of the alkali metals, in an amount up to 29 mol per cent such that the total proportion of Tl 2 O and R 2 O is 10-30 mol per cent and optionally other compatible ingredients, said glass body having a uniform refractive index, with a source of at least one of sodium, potassium, lithium, rubidium and caesium ions at 400-600‹ C. In order to prevent devitrification of the glass when heated the glass composition preferably contains at least one of the compounds of formulµ R<SP>1</SP>O, R<SP>11</SP> 2 O 3 (apart from B 2 O 3 and R<SP>111</SP>O 2 (apart from SiO 2 ) where R<SP>1</SP> is a divalent atom such as Mg, Ca, Ba, Zn or Pb(II); R<SP>11</SP> is a trivalent atom such as Al; and R<SP>111</SP> is a tetravalent atom such as Sn(IV) or Ti 3 in a total proportion of 1-20 mol. per cent. The incorporation of 2-15 mol per cent ZnO is particularly suitable in this respect. The glass body may be suitably drawn or cut to form an optical fibre or a lens respectively. A typical glass composition suitable for use in the production of an optical fibre comprises 1À0-5À5 mol per cent Tl 2 O, 50-70 mol per cent SiO 2 , 10-30 mol per cent B 2 O 3 , 6À5-29 mol per cent R 2 O such that the total proportion of Tl 2 O and R 2 O is 10-30 mol per cent, and optionally at least one of the oxides MgO, CaO, BaO, ZnO, PbO, Al 2 O 3 , SnO 2 and TiO 2 , the total amount of said oxides being at most 15 mol per cent. A typical glass composition for use in the production of the present invention comprises 5À5-25 mol per cent TiO 2 , 50-65 mol per cent SiO 2 , 10-25 mol per cent B 2 O 3 , 6À5-24À5 mol per cent R 2 O such that the total amount of Tl 2 O and R 2 O is 15-30 mol per cent, and optionally at least one of the oxides MgO, CaO, BaO, ZnO, PbO, Al 2 O 3 , SnO 2 and TiO 2 , the total amount of said oxides being 1-20 mol per cent. The glass may also contain traces of AS 2 O 3 as fining agent. Fig. 1 indicates the concentration of the ions at a radial distance from the central axis in a direction perpendicular to the central axis of the rod during the ion exchange:-curve 1 being the concentration of T1<SP>+</SP> during the initial stage of ion exchange, the ion exchange occurring near the surface of the glass rod; curve 1<SP>1</SP> being the concentration of ions diffusing from the external ion source, e.g. K<SP>+</SP>, during the initial stage (i.e. at the central rod concentration of K<SP>+</SP> is zero) ; curves 2 and 2<SP>1</SP> being the concentrations of T1<SP>+</SP> and K+ when the K<SP>+</SP> ions have almost reached the centre of the rod; and curves 3 and 3<SP>1</SP> being the concentrations of TI<SP>+</SP> and K<SP>+</SP> when the ion exchange has proceeded still further. It can be seen that the concentration of thallium ions at the centre of the rod is lower than that before ion exchange, while the concentration of potassium ions at the centre of the rod is higher. In many cases the concentration of thallium ions at the peripheral surface of the glass rod is almost zero. The preferred diameter of the glass body of the invention is 0À03-10 mm. and the difference in refractive indices between the central axis and the peripheral surface is preferably 0À005-0À15. The glass body may also be produced by a process comprising melting the glass in the inside pot of a double platinum pot while melting in the outside pot a different class of glass containing an alkali metal ion, and then effecting the mutual heatdiffusion of the thallium ions contained in the inside pot and the alkali metal ions contained in the outer pot during the spinning of a glass fibre from the double platinum pot.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP47025018A JPS5129524B2 (en) | 1972-03-10 | 1972-03-10 | |
JP3233772A JPS5317605B2 (en) | 1972-03-30 | 1972-03-30 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1413891A true GB1413891A (en) | 1975-11-12 |
Family
ID=26362621
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1112573A Expired GB1413891A (en) | 1972-03-10 | 1973-03-07 | Optical glass bodies |
Country Status (3)
Country | Link |
---|---|
FR (1) | FR2175934B1 (en) |
GB (1) | GB1413891A (en) |
NL (1) | NL173514C (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2140169A (en) * | 1983-04-21 | 1984-11-21 | American Telephone & Telegraph | A single mode lightguide fiber |
GB2148529A (en) * | 1983-09-02 | 1985-05-30 | Canon Kk | Graded refractive index lens |
GB2176627A (en) * | 1985-05-07 | 1986-12-31 | Nippon Sheet Glass Co Ltd | Graded index collimator lens |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH657118A5 (en) * | 1984-03-07 | 1986-08-15 | Battelle Memorial Institute | ALUMINOSILICATE OPTICAL LENSES. |
-
1973
- 1973-03-07 GB GB1112573A patent/GB1413891A/en not_active Expired
- 1973-03-09 NL NL7303343A patent/NL173514C/en not_active IP Right Cessation
- 1973-03-12 FR FR7308752A patent/FR2175934B1/fr not_active Expired
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2140169A (en) * | 1983-04-21 | 1984-11-21 | American Telephone & Telegraph | A single mode lightguide fiber |
GB2148529A (en) * | 1983-09-02 | 1985-05-30 | Canon Kk | Graded refractive index lens |
GB2176627A (en) * | 1985-05-07 | 1986-12-31 | Nippon Sheet Glass Co Ltd | Graded index collimator lens |
Also Published As
Publication number | Publication date |
---|---|
FR2175934B1 (en) | 1976-09-24 |
DE2311823A1 (en) | 1973-09-13 |
NL7303343A (en) | 1973-09-12 |
FR2175934A1 (en) | 1973-10-26 |
DE2311823B2 (en) | 1976-02-19 |
NL173514C (en) | 1984-02-01 |
NL173514B (en) | 1983-09-01 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PE20 | Patent expired after termination of 20 years |
Effective date: 19930306 |