US4426216A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing optical glass
Assignee: Hitachi Cable Ltd
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Filing: 1982-01-06
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Granted: 1984-01-17
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Expires: 2002-01-06
Abstract
Abstract Optical glass is produced by heating a porous gel to a high temperature to partly sinter it, heating it in a chlorine-containing atmosphere to subject it to hydroxyl group removal treatment, and then further heating it to sinter it. The optical glass produced by this process does not rise in bubbles even when heated.
Inventors
- 👤 Shin Satoh
- 👤 Kenzo Susa
- 👤 Iwao Matsuyama
- 👤 Tsuneo Suganuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:10
CPC Classifications
C; C03; C03B; C03B19/00; C03B19/12; C03C; C03C1/00; C03C1/006; C03B2201/00; C03B2201/02; C03B2201/03; C03B2201/04; C03B2201/06; C03B2201/07; C03B2201/075; Y; Y10; Y10S; Y10S65/00; Y10S65/901
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
132 words
A process for producing optical glass which comprises: (i) a step of partly sintering a porous hydrolyzed alkoxide gel by heating said gel to a high temperature and for a time sufficient such that said gel is partly sintered until the specific surface area of said gel becomes 30 to 100 m 2 /g, (ii) a step of subjecting the partly sintered gel to a hydroxyl group removal treatment by heating it in a chlorine-containing atmosphere to a temperature lower than the heating temperature in the above-mentioned step (i) such that sintering does not occur during step (ii), and (iii) a step of sintering said gel by heating it to a temperature higher than the heating temperature in the abovementioned step (ii) and for a time sufficient to produce said optical glass.
Claim 2
Dependent Claim
132 words
A process for producing optical glass which comprises: (i) a step of partly sintering a porous hydrolyzed alkoxide gel by heating said gel to a high temperature and for a time sufficient such that said gel is partly sintered until the specific surface area of said gel becomes 30 to 100 m 2 /g, (ii) a step of subjecting the partly sintered gel to a hydroxyl group removal treatment by heating it in a chlorine-containing atmosphere to a temperature lower than the heating temperature in the above-mentioned step (i) such that sintering does not occur during step (ii), and (iii) a step of sintering said gel by heating it to a temperature higher than the heating temperature in the abovementioned step (ii) and for a time sufficient to produce said optical glass.
Claim 3
Dependent Claim
17 words
A process for producing optical glass according to claim 1, wherein said porous gel is silica gel.
Claim 4
Dependent Claim
65 words
A process for producing optical glass according to claim 1, wherein, prior to step (i), the porous hydrolyzed alkoxide gel is prepared by freeing a hydrolyzed metal alkoxide of adsorbed water and alcohol by heating and then subjecting the freed alkoxide to OCH 3 group removal treatment by further heating to a temperature higher than the temperature used for freeing the adsorbed water and alcohol.
Claim 5
Dependent Claim
22 words
A process for producing optical glass according to claim 1, wherein said specific surface area is 100 to 70 m 2 /g.
Claim 6
Dependent Claim
38 words
A process for producing optical glass according to claim 1, 2 or 4, wherein the atmosphere in said step (i) is at least one member selected from the group consisting of oxygen, inert gases, neutral gases and air.
Claim 7
Dependent Claim
22 words
A process for producing optical glass according to claim 5, wherein the atmosphere in said step (i) is a gas containing He.
Claim 8
Dependent Claim
28 words
A process for producing optical glass according to claim 5, wherein the atmosphere in said step (i) is a gas containing 50% by volume or more of He.
Claim 9
Dependent Claim
30 words
A process for producing optical glass according to claim 5, wherein the atmosphere in said step (i) is a gas containing oxygen and 50% by volume or more of He.
Claim 10
Dependent Claim
28 words
A process for producing optical glass according to claim 2, wherein said silica gel in step (i) is heated to a temperature between 950° C. to 1,100° C.
Claim 11
Dependent Claim
22 words
A process for producing optical glass according to claim 9, wherein the heating in step (i) is performed 0.1 to 1.0 hours.
Claim 12
Dependent Claim
23 words
A process for producing optical glass according to claim 10, wherein the heating in step (i) is carried out in an oxidizing atmosphere.
Claim 13
Dependent Claim
27 words
A process for producing optical glass according to claim 1, wherein said gel in step (ii) is heated to a temperature between 400° C. to 1,000° C.
Claim 14
Dependent Claim
27 words
A process for producing optical glass according to claim 12, wherein said gel in step (ii) is heated to a temperature between 700° C. to 900° C.
Claim 15
Dependent Claim
27 words
A process for producing optical glass according to claim 1, wherein said gel in step (iii) is heated to a temperature between 1,050° C. to 1,300° C.
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) | 1987-01-16 | 1987-07-18 | 1988-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-16 | 1991-07-18 | 1992-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-16 | 1995-07-18 | 1996-01-17 | $7700.00 | Window Closed / Lapsed |