US4982289A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid cooled cathode ray tube apparatus for video projection system
Assignee: Panasonic Holdings Corp
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Filing: 1989-05-15
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Granted: 1991-01-01
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Expires: 2009-05-15
Abstract
Abstract In a video projector for projecting video images on phosphor screens of cathode ray tubes to a screen, a refrigerant mixture of ethylene glycol, diethylene glycol and glycerine is filled in watertight spaces enclosed by the cathode ray tubes, radiators and projection lenses.
Inventors
- 👤 Katsuaki Mitani
- 👤 Isao Matsuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:18
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/86; H01J29/89; H01J29/894
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
90 words
A liquid cooled cathode ray tube apparatus for a video projection system comprising: a cathode ray tube for making a video image; a plastic projection lens disposed in front of said cathode ray tube for projecting said video image to a predetermined position; a radiator disposed between said cathode ray tube and said projection lens; and a transparent refrigerant fluid consisting essentially of a mixture of ethylene glycol, diethylene glycol and glycerine and watertightly filled in a space defined by said cathode ray tube, said projection lens and said radiator.
Claim 2
Dependent Claim
90 words
A liquid cooled cathode ray tube apparatus for a video projection system comprising: a cathode ray tube for making a video image; a plastic projection lens disposed in front of said cathode ray tube for projecting said video image to a predetermined position; a radiator disposed between said cathode ray tube and said projection lens; and a transparent refrigerant fluid consisting essentially of a mixture of ethylene glycol, diethylene glycol and glycerine and watertightly filled in a space defined by said cathode ray tube, said projection lens and said radiator.
Claim 3
Dependent Claim
47 words
A liquid cooled cathode ray tube apparatus for a video projection system according to claim 1, wherein said refrigerant fluild consists essentially of 80 to 50 wt % of ethylene glycol, 10 to 40 wt % of diethylene glycol and 5 to 40 wt % of glycerine.
Claim 4
Dependent Claim
33 words
A liquid cooled cathode ray tube apparatus for a video projection system according to claim 1, wherein said refrigerant fluid has an index of refraction similar to that of said plastic projection lens.
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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) | 1993-12-31 | 1994-07-02 | 1995-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-31 | 1998-07-02 | 1999-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-31 | 2002-07-02 | 2003-01-01 | $7700.00 | Window Closed / Lapsed |