US5247190A
Expired / Lapsed
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Electroluminescent devices
Assignee: Cambridge Display Technology Ltd
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Filing: 1990-04-18
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Granted: 1993-09-21
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Expires: 2010-04-18
Abstract
Abstract An electroluminescent device comprises a semiconductor layer (4) in the form of a thin dense polymer film comprising at least one conjugated polymer, a first contact layer (5) in contact with a first surface of the semiconductor layer, and a second contact layer (3) in contact with a second surface of the semiconductor layer. The polymer firm (4) of the semiconductor layer has a sufficiently low concentration of extrinsic charge carriers that on applying an electric field between the first and second contact layers across the semiconductor layer so as to render the second contact layer positive relative to the first contact layer charge carriers are injected into the semiconductor layer and radiation is emitted from the semiconductor layer. The polymer film can be poly(p-phenyenevinylene) [PPV] of formula (I) wherein the phenylene ring may optionally carry one or more substituents each independently selected from alkyl (preferably methyl), alkoxy (preferably methoxy or ethoxy), halogen (preferably chlorine or bromine) or nitro.
Inventors
- 👤 Richard H. Friend
- 👤 Jeremy H. Burroughes
- 👤 Donal D. Bradley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:57
CPC Classifications
H; H05; H05B; H05B33/00; H05B33/12; H05B33/14; H10; H10K; H10K85/00; H10K85/10; H10K85/111; H10K85/114; C; C09; C09K; C09K11/00; C09K11/06; H10K50/00; H10K50/10; H10K50/11; H10K71/00; H10K71/10; H10K71/191; H10K85/113
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
169 words
An electroluminescent device comprising: a semiconductor layer in the form of a thin dense polymer film comprising at least one conjugated polymer; a first contact layer which is selected so that on application of an electric field to said device charge carriers of a first type are injected into the semiconductor layer; and a second contact layer which is selected so that on application of an electric field to said device charge carriers of a second type are injected into the semiconductor layers, wherein the polymer film of the semiconductor layer has a sufficiently low concentration of extrinsic charge carriers that on applying an electric field between the first and second contact layers across the semiconductor layer so as to render the second contact layer positive relative to the first contact layer charge carriers of said first and second types are injected into the semiconductor layer and combine to form in the conjugated polymer charge carrier pairs which decay radiatively so that radiation is emitted from the conjugated polymer.
Claim 2
Dependent Claim
169 words
An electroluminescent device comprising: a semiconductor layer in the form of a thin dense polymer film comprising at least one conjugated polymer; a first contact layer which is selected so that on application of an electric field to said device charge carriers of a first type are injected into the semiconductor layer; and a second contact layer which is selected so that on application of an electric field to said device charge carriers of a second type are injected into the semiconductor layers, wherein the polymer film of the semiconductor layer has a sufficiently low concentration of extrinsic charge carriers that on applying an electric field between the first and second contact layers across the semiconductor layer so as to render the second contact layer positive relative to the first contact layer charge carriers of said first and second types are injected into the semiconductor layer and combine to form in the conjugated polymer charge carrier pairs which decay radiatively so that radiation is emitted from the conjugated polymer.
Claim 3
Dependent Claim
48 words
An electroluminescent device as claimed in claim 1, wherein the conjugated polymer is poly(p-phenylenevinylene) [PPV] of formula ##STR5## wherein the phenylene ring may optionally carry one or more substituents each independently selected from alkyl (preferably methyl), alkoxy (preferably methoxy or ethoxy), halogen (preferably chlorine or bromine), or nitro.
Claim 4
Dependent Claim
28 words
An electroluminescent device as claimed in claim 1, wherein the thin dense polymer film is of substantially uniform thickness in the range of 10 nm to 5 μm.
Claim 5
Dependent Claim
25 words
An electroluminescent device as claimed in claim 4, wherein the conjugated polymer has a semiconductor band gap in the range 1 eV to 3.5 eV.
Claim 6
Dependent Claim
39 words
An electroluminescent device as claimed claim 1, wherein the proportion of the conjugated polymer in electroluminescent areas of the polymer film is sufficient to achieve the percolation threshold for charge transport in the conjugated polymer present in the film.
Claim 7
Dependent Claim
43 words
An electroluminescent device as claimed claim 1, wherein the first charge injecting contact layer is a thin layer of aluminium one surface having formed a thin oxide layer, the first surface of the semiconductor layer being in contact with the said oxide layer.
Claim 8
Dependent Claim
26 words
An electroluminescent device as claimed claim 1, wherein the first contact layer is selected from the group comprising aluminium or an alloy of magnesium and silver.
Claim 9
Dependent Claim
24 words
An electroluminescent device as claimed in claim 6, wherein the second charge injecting contact layer is selected from the group comprising aluminium and gold.
Claim 10
Dependent Claim
24 words
An electroluminescent device as claimed claim 1, wherein at least one of the first and second charge injecting contact layers is at least semitransparent.
Claim 11
Dependent Claim
20 words
An electroluminescent device as claimed in claim 7, wherein the second contact layer comprises indium oxide or indium tin oxide.
Claim 12
Dependent Claim
31 words
An electroluminescent device as claimed claim 1 wherein the first contact layer comprises amorphous silicon and the second contact layer is selected from the group comprising aluminium, gold and indium oxide.
Claim 13
Dependent Claim
30 words
An electroluminescent device as claimed in claim 1, wherein at least of one of the first and second charge injecting contact layers is also in contact with a supporting substrate.
Claim 14
Dependent Claim
15 words
An electroluminescent device as claimed in claim 9, wherein the supporting substrate is silica glass.
Claim 15
Dependent Claim
30 words
An array of electroluminescent devices, each electroluminescent device as claimed in claim 1, said first and second charge injecting contact layers being arranged to permit selective addressing in said array.
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) | 1996-09-20 | 1997-03-22 | 1997-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-20 | 2001-03-22 | 2001-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-20 | 2005-03-22 | 2005-09-21 | $7700.00 | Window Closed / Lapsed |