US4282022A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making polarizing glasses through extrusion
Assignee: Corning Glass Works
•
Filing: 1980-04-28
•
Granted: 1981-08-04
•
Expires: 2000-04-28
Abstract
Abstract The present invention relates to the preparation of polarizing glasses from silver-containing glasses characterized by the presence of metallic silver particles therein and/or by being photochromic through the inclusion of silver halide particles therein selected from the group of AgCl, AgBr, and AgI. The method contemplates extruding the glass at a temperature between the annealing and softening points of the glass at a sufficiently high applied pressure to elongate the metallic silver and/or silver halide particles to an aspect ratio of at least 2:1 and up to 30:1 and greater. The extrudate is cooled in a manner to prevent the elongated particles from resuming their original shape. Dichroic ratios of up to 5.0 are achievable where the elongated particles exhibit an oblate configuration.
Inventors
- 👤 Kuang-Hsin K. Lo
- 👤 Daniel A. Nolan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:15
CPC Classifications
C; C03; C03C; C03C4/00; C03C4/04; C03C4/06; C03B; C03B17/00; C03B17/06
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
113 words
A method for making glass exhibiting polarizing properties from silver-containing glasses characterized as containing particles of metallic silver and/or as being photochromic through the presence of silver halide particles therein selected from the group of AgCl, AgBr, and AgI, which comprises the steps of: (a) extruding said glass at an elevated temperature between about the annealing and softening points of the glass at an applied pressure of at least 3000 psi to elongate said metallic silver and/or silver halide particles to an aspect ratio of at least 2:1 and align them in the direction of glass flow; and then (b) subjecting the extrudate to conditions sufficient to inhibit respheroidization of the elongated particles.
Claim 2
Independent Claim
113 words
A method for making glass exhibiting polarizing properties from silver-containing glasses characterized as containing particles of metallic silver and/or as being photochromic through the presence of silver halide particles therein selected from the group of AgCl, AgBr, and AgI, which comprises the steps of: (a) extruding said glass at an elevated temperature between about the annealing and softening points of the glass at an applied pressure of at least 3000 psi to elongate said metallic silver and/or silver halide particles to an aspect ratio of at least 2:1 and align them in the direction of glass flow; and then (b) subjecting the extrudate to conditions sufficient to inhibit respheroidization of the elongated particles.
Claim 3
Dependent Claim
19 words
A method according to claim 1 wherein the extrusion is carried out at a temperature between about 400°-1100° C.
Claim 4
Dependent Claim
20 words
A method according to claim 1 wherein the extrusion is carried out at an applied pressure of about 5000-500,000 psi.
Claim 5
Dependent Claim
25 words
A method according to claim 1 wherein said particles after extrusion exhibit a prolate shape and said glass demonstrates a dichroic ratio of about 1.8-3.0.
Claim 6
Dependent Claim
25 words
A method according to claim 1 wherein said particles after extrusion exhibit an oblate shape and said glass demonstrates a dichroic ratio of about 1.8-5.0.
Claim 7
Dependent Claim
19 words
A method according to claim 1 wherein respheroidization of the elongated particles is inhibited by quickly cooling the extrudate.
Claim 8
Dependent Claim
21 words
A method according to claim 1 wherein respheroidization of the elongated particles is inhibited by utilizing a temperature gradient extrusion die.
Claim 9
Dependent Claim
22 words
A method according to claim 1 wherein respheroidization of the elongated particles is inhibited by maintaining the extrudate under tension during cooling.
Claim 10
Independent Claim
186 words
A method for making glass strip exhibiting polarizing properties from silver-containing glasses characterized as containing particles of metallic silver and/or as being photochromic through the presence of silver halide particles therein selected from the group of AgCl, AgBr, and AgI, said strip having a concavo-convex configuration across the width thereof and a linear curvature therein, which comprises the steps of: (a) extruding said glass at an elevated temperature between about the annealing and softening points of the glass at an applied pressure of at least 3000 psi to elongate said metallic silver and/or silver halide particles to an aspect ratio of at least 2:1 and align them in the direction of glass flow, said extrusion being carried out utilizing a die structure having a curved slot orifice; (b) passing said glass into a channel having a cross-sectional configuration similar to that of said curved slot orifice and having a bend therein to form a glass strip having a concavo-convex configuration across the width thereof and a linear curvature therein; and then (c) subjecting said glass strip to conditions sufficient to inhibit respheroidization of the elongated particles.
Claim 11
Independent Claim
186 words
A method for making glass strip exhibiting polarizing properties from silver-containing glasses characterized as containing particles of metallic silver and/or as being photochromic through the presence of silver halide particles therein selected from the group of AgCl, AgBr, and AgI, said strip having a concavo-convex configuration across the width thereof and a linear curvature therein, which comprises the steps of: (a) extruding said glass at an elevated temperature between about the annealing and softening points of the glass at an applied pressure of at least 3000 psi to elongate said metallic silver and/or silver halide particles to an aspect ratio of at least 2:1 and align them in the direction of glass flow, said extrusion being carried out utilizing a die structure having a curved slot orifice; (b) passing said glass into a channel having a cross-sectional configuration similar to that of said curved slot orifice and having a bend therein to form a glass strip having a concavo-convex configuration across the width thereof and a linear curvature therein; and then (c) subjecting said glass strip to conditions sufficient to inhibit respheroidization of the elongated particles.
References Cited (Backward Citations)
US3208860A
Cited
US3467513A
Cited
US3548060A
Cited
US3834912A
Cited
US3653863A
Cited
US3703388A
Cited
US3876436A
Cited
US3957498A
Cited
US4125405A
Cited
US4190451A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-03 | 1985-02-02 | 1985-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-03 | 1989-02-02 | 1989-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-03 | 1993-02-02 | 1993-08-04 | $7700.00 | Window Closed / Lapsed |