Patent US4174490A successfully refreshed from Google Patents.
US4174490A
Expired / Lapsed
US
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Cathode-ray tube
Assignee: US Philips Corp
•
Filing: 1978-05-19
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Granted: 1979-11-13
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Expires: 1998-05-19
Abstract
Abstract Disclosed is a cathode-ray tube having a face plate of soft glass which up to an accelerating voltage of 40 KV gives an X-ray emission of at most 0.5 mr/h measured at a distance of 5 cm. The glass has a strain point between 450 DEG and 480 DEG C. and a softening temperature between 660 DEG and 770 DEG C. and comprises, inter alia, 3-14% by weight of BaO and 5-10% by weight of PbO.
Inventors
- 👤 Klaus C. Van Erk
- 👤 Marinus Ploeger
- 👤 Peter H. Von Reth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:33
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/86; H01J29/863; C; C03; C03C; C03C3/00; C03C3/04; C03C3/076; C03C3/102; C03C3/105
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
119 words
In a colour television cathode ray tube included an evacuated glass envelope having a glass face plate, a fluorescent layer having a pattern of phosphor regions on the inner surface thereof, and at least one electron gun disposed in said envelope opposite said face plate, the improvement wherein said glass of said face plate consists essentially of, in percent by weight: ______________________________________
SiO.sub.2
60-68 SrO 0-1
Al.sub.2 O.sub.3
0-6 PbO 5-10
Na.sub.2 O
5-12 combined
ZrO.sub.2 0-3
K.sub.2 O
3-11 >13 CeO.sub.2 0-0.6
CaO 0-1 Sb.sub.2 O.sub.3 + As.sub.2 O.sub.3
0.3-0.7
MgO 0-2 F 0-1.5
BaO 3-14 TiO.sub.2 0-0.3
______________________________________ with the complementary conditions that Al 2 O 3 +ZrO 2 >2 BaO+2SrO+2ZrO 2 +3PbO>28 and 3CaO+2MgO+SrO+4ZrO 2 <12
Claim 2
Dependent Claim
119 words
In a colour television cathode ray tube included an evacuated glass envelope having a glass face plate, a fluorescent layer having a pattern of phosphor regions on the inner surface thereof, and at least one electron gun disposed in said envelope opposite said face plate, the improvement wherein said glass of said face plate consists essentially of, in percent by weight: ______________________________________
SiO.sub.2
60-68 SrO 0-1
Al.sub.2 O.sub.3
0-6 PbO 5-10
Na.sub.2 O
5-12 combined
ZrO.sub.2 0-3
K.sub.2 O
3-11 >13 CeO.sub.2 0-0.6
CaO 0-1 Sb.sub.2 O.sub.3 + As.sub.2 O.sub.3
0.3-0.7
MgO 0-2 F 0-1.5
BaO 3-14 TiO.sub.2 0-0.3
______________________________________ with the complementary conditions that Al 2 O 3 +ZrO 2 >2 BaO+2SrO+2ZrO 2 +3PbO>28 and 3CaO+2MgO+SrO+4ZrO 2 <12
Claim 3
Dependent Claim
77 words
A glass composition for a face plate of a cathode ray tube consisting essentially of, in percent by weight: ______________________________________
SiO.sub.2
60-68 SrO 0-1
Al.sub.2 O.sub.3
0-6 PbO 5-10
Na.sub.2 O
5-12 combined
ZrO.sub.2 0-3
K.sub.2 O
3-11 >13 CeO.sub.2 0-0.6
CaO 0-1 Sb.sub.2 O.sub.3 + As.sub.2 O.sub.3
0.3-0.7
MgO 0-2 F 0-1.5
BaO 3-14 TiO.sub.2 0-0.3
______________________________________ with the complementary conditions that Al 2 O 3 +ZrO 2 >2 BaO+2SrO+2ZrO 2 +3PbO>28 and 3CaO+2MgO+SrO+4ZrO 2 <12
Claim 4
Dependent Claim
77 words
A glass composition for a face plate of a cathode ray tube consisting essentially of, in percent by weight: ______________________________________
SiO.sub.2
60-68 SrO 0-1
Al.sub.2 O.sub.3
0-6 PbO 5-10
Na.sub.2 O
5-12 combined
ZrO.sub.2 0-3
K.sub.2 O
3-11 >13 CeO.sub.2 0-0.6
CaO 0-1 Sb.sub.2 O.sub.3 + As.sub.2 O.sub.3
0.3-0.7
MgO 0-2 F 0-1.5
BaO 3-14 TiO.sub.2 0-0.3
______________________________________ with the complementary conditions that Al 2 O 3 +ZrO 2 >2 BaO+2SrO+2ZrO 2 +3PbO>28 and 3CaO+2MgO+SrO+4ZrO 2 <12
References Cited (Backward Citations)
US3794502A
Cited
US3464932A
Cited
US3663246A
Cited
US4065697A
Cited
US4065696A
Cited
US3907584A
Cited
US3819972A
Cited
US3925089A
Cited
JPS5087405A
Cited
US3987330A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-11-12 | 1983-05-14 | 1983-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-12 | 1987-05-14 | 1987-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-12 | 1991-05-14 | 1991-11-13 | $7700.00 | Window Closed / Lapsed |