US4435200A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing precision pressed glass object
Assignee: US Philips Corp
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Filing: 1982-07-08
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Granted: 1984-03-06
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Expires: 2002-07-08
Abstract
Abstract Glass objects, lenses in particular, can be pressed with precision from a glass which contains 45-55 mol. % P 2 O 5 , 15-40 mol. % BaO, 5-15 mol. % Li 2 O, 5-35 mol. % PbO, 0-2 mol. % Al 2 O 3 and 0-6 mol. % F. A cube of glass is made from the above composition and preheated to a temperature of 20°-60° C. above the American softening point to obtain a polishing effect. The preheated cube is then inserted into preheated dies which are closed to form a precision pressed object of the glass.
Inventors
- 👤 Hendrik J. M. Joormann
- 👤 Hendrik Verweij
- 👤 Jan Haisma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 08:46
CPC Classifications
G; G02; G02B; G02B1/00; C; C03; C03C; C03C3/00; C03C3/12; C03C3/16; C03C3/17; C03C3/23; C03C3/247; Y; Y10; Y10S; Y10S359/00; Y10S359/90; Y10S501/00; Y10S501/90; Y10S501/903
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
171 words
A method of forming a precision pressed object of glass comprising the steps of precisely grinding a cube of glass having a composition consisting essentially of 45-55 mol.% P 2 O 5 , 15-40 mol.% BaO, 5-35 mol.% PbO, 5-15 mol.% Li 2 O, 0-2 mol.% Al 2 O 3 , and 0-6 mol.% F in the form of fluoride wherein up to 25% of BaO may be replaced by an equimolar quantity of at least one of CaO, MgO and SrO, and up to 25% of Li 2 O may be replaced by an equimolar quantity of at least one other alkali metal oxide; positioning said cube on a carrier; preheating said cube to a temperature 20°-60° C. above the American softening point to obtain a polishing effect; preheating dies of a glass forming device to a temperature 10°-40° C. above the American softening point of said glass; inserting said preheated cube and carrier into said dies; and closing said dies to form a precision pressed object of said glass.
Claim 2
Independent Claim
171 words
A method of forming a precision pressed object of glass comprising the steps of precisely grinding a cube of glass having a composition consisting essentially of 45-55 mol.% P 2 O 5 , 15-40 mol.% BaO, 5-35 mol.% PbO, 5-15 mol.% Li 2 O, 0-2 mol.% Al 2 O 3 , and 0-6 mol.% F in the form of fluoride wherein up to 25% of BaO may be replaced by an equimolar quantity of at least one of CaO, MgO and SrO, and up to 25% of Li 2 O may be replaced by an equimolar quantity of at least one other alkali metal oxide; positioning said cube on a carrier; preheating said cube to a temperature 20°-60° C. above the American softening point to obtain a polishing effect; preheating dies of a glass forming device to a temperature 10°-40° C. above the American softening point of said glass; inserting said preheated cube and carrier into said dies; and closing said dies to form a precision pressed object of said glass.
Claim 3
Dependent Claim
42 words
A method according to claim 1, wherein said glass has a composition of 45-55 mol.% P 2 O 5 , 15-35 mol.% BaO, 9-22 mol.% PbO, 8.5-11.5 mol.% Li 2 O, 0-2 mol.% Al 2 O 3 , and 0-6 mol.% F.
Claim 4
Dependent Claim
42 words
A method according to claim 1, wherein said glass has a composition of 46-52 mol.% P 2 O 5 , 18-22 mol.% BaO, 18-22 mol.% PbO, 9-11 mol.% Li 2 O, 0-2 mol.% Al 2 O 3 , and 0-6 mol.% F.
Claim 5
Dependent Claim
18 words
A method according to claim 1, wherein said precision pressed object of said glass is an optical lens.
Claim 6
Dependent Claim
26 words
A method according to claim 1, wherein said American softening point is the temperature at which the viscosity of said glass is 10 7 .6 poise.
Claim 7
Dependent Claim
19 words
A method according to claim 1, wherein said precision pressing is carried out at a temperature of 440° C.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-06 | 1987-09-05 | 1988-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-06 | 1991-09-05 | 1992-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-06 | 1995-09-05 | 1996-03-06 | $7700.00 | Window Closed / Lapsed |