US4228490A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Display device for use with strong illumination
Assignee: US Philips Corp
•
Filing: 1978-08-21
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Granted: 1980-10-14
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Expires: 1998-08-21
Abstract
Abstract An electroluminescent device includes at least one emissive diode emitting in the red. The emissive face of the diode is covered by a filter element which is substantially transparent in the red, and which has a light transmission coefficient in the blue which is significantly higher than its coefficient in the yellow and the green. The resulting device exhibits superior contrast in sunlight, and is thus particularly suitable for use in vehicle and aircraft dashboard displays.
Inventors
- 👤 Jacques-Claude Thillays
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:02
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/84; H10H20/85; H10H20/852; H10H20/854; H10W; H10W90/00; H10W90/701; H10W90/751; H10W90/756; Y; Y10; Y10S; Y10S362/00; Y10S362/80
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
62 words
An electroluminescent device comprising at least one emissive diode emitting in the red, a filter element which is substantially transparent in the red and which covers the emissive face of said diode, the light transmission coefficient of said filter element in the blue being significantly higher than the light transmission coefficient of said filter element in the yellow and in the green.
Claim 2
Dependent Claim
62 words
An electroluminescent device comprising at least one emissive diode emitting in the red, a filter element which is substantially transparent in the red and which covers the emissive face of said diode, the light transmission coefficient of said filter element in the blue being significantly higher than the light transmission coefficient of said filter element in the yellow and in the green.
Claim 3
Dependent Claim
52 words
An electroluminescent device as claimed in claim 1, wherein said light transmission coefficient is at least equal to 70% for radiation in the wavelength band of between 0.40 and 0.48 μm and said light transmission coefficient is lower than 60% for radiation in the wavelength band of between 0.52 and 0.58 μm.
Claim 4
Dependent Claim
42 words
An electroluminescent device as claimed in any of the preceding claims, wherein said filter element is manufactured from a thermosetting plastic material which in itself is transparent and which comprises a comparatively very small dose of a dye of the shade blue-violet.
Claim 5
Dependent Claim
20 words
An electroluminescent device as claimed in claim 3, wherein said plastic material is an epoxide resin of the cycloaliphatic series.
Claim 6
Dependent Claim
30 words
An electroluminescent device as claimed in claim 3, wherein said dye is selected from a group consisting of the condensation products of the reaction between a hydroxyanthraquinone and an amine.
Claim 7
Dependent Claim
22 words
An electroluminescent device as claimed in claim 5, wherein said dye consists of anthraquinone 4-hydro 1-p-aminotoluene according to the chemical formula ##STR2##
Claim 8
Dependent Claim
23 words
An electroluminescent device as claimed in claim 4, wherein the weight ratio between the dye and the resin is between 0.008 and 0.012%.
Claim 9
Dependent Claim
48 words
An electroluminescent device as claimed in claim 4, wherein the initially prepared resin mixture for the formation of filter elements has the following weight ratio: ______________________________________
cycloaliphatic epoxide resin
100 ± 5
carboxylane anhydride hardener
105 ± 5
benzyldimethylamine accelerator
1 ± 0.5
dye 0.01 ± 0.002.
______________________________________
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) | 1983-10-14 | 1984-04-14 | 1984-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-14 | 1988-04-14 | 1988-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-14 | 1992-04-14 | 1992-10-14 | $7700.00 | Window Closed / Lapsed |