US3576356A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Antiglare coating for cathode-ray tube used with capacitive coupled voltage pen
Assignee: International Business Machines Corp
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Filing: 1969-01-14
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Granted: 1971-04-27
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Expires: 1989-01-14
Abstract
Abstract A multilayer optical transparent coating in conjunction with a circular polarizer that reduces glare and provides capacitive coupled voltage pen action. The transparent multilayer antireflective coating circular polarizer structure permits visual observation of the information on the face of the cathoderay tube with minimum glare and reflection and also maintains a potential field across one of the layers of the antireflective coating. The potential field is utilized for correlating a pen position on the outer surface of the multilayer coating.
Inventors
- 👤 Clifton E Hyman
- 👤 George M Krembs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:07
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/86; H01J29/89; H01J2229/00; H01J2229/89; H01J2229/8913
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
195 words
An antiglare cathode-ray tube faceplate coating for usE in a graphic display system having a capacitive-coupled voltage pen input comprising: a first surface which forms the faceplate of said cathode-ray tube; a circular polarizer bonded to said first surface for suppressing reflected light from said faceplate; a first layer of transparent crystalline material bonded to said circular polarizer having a refractive index in the range of 1.60 to 1.80 and a thickness which is a factor of lambda /4 where lambda is a wavelength of light in the visible region of the spectrum; a second layer of transparent semiconductor material bonded to said first layer having a refractive index in the range of 1.90 to 2.60 and a thickness which is a factor of lambda /4 where lambda is a wavelength of light in the visible region of the spectrum; a third layer of transparent dielectric material bonded to said second layer and forming an outer surface; said third layer having a refractive index in the range of 1.35 to 1.50 and a thickness which is a factor of lambda /4 where lambda is a wavelength of light in the visible region of the spectrum.
Claim 2
Dependent Claim
31 words
The structure as defined in claim 2 wherein said circular polarizer comprises a single plane polarizing film mated with a quarter-wavelength retarder, where said wavelength is chosen in the visible spectrum.
Claim 3
Dependent Claim
35 words
The structure as defined in claim 3 wherein the thickness of said first, second, and third layers are factors of lambda /4 where lambda is the wavelength of light at 550nm. in the visible region.
References Cited (Backward Citations)
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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) | 1974-04-26 | 1974-10-26 | 1975-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-26 | 1978-10-26 | 1979-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-26 | 1982-10-26 | 1983-04-27 | $7700.00 | Window Closed / Lapsed |