US5807627A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electroluminescent devices
Assignee: Cambridge Display Technology Ltd
•
Filing: 1993-07-26
•
Granted: 1998-09-15
•
Expires: 2013-07-26
Abstract
Abstract An electroluminescent device has at least two active semiconductive conjugated polymer light emitting layers arranged between a cathode and an anode. The layers are arranged so that at least part of at least two layers lie in an emission zone of the device.
Inventors
- 👤 Richard Henry Friend
- 👤 Andrew Bruce Holmes
- 👤 Donal Donat Conor Bradley
- 👤 Paul Leslie Burn
- 👤 Arno Kraft
- 👤 Adam Richard Brown
- 👤 Jeremy Henley Burroughes
- 👤 Neil Clement Greenham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:36
CPC Classifications
H; H05; H05B; H05B33/00; H05B33/12; H05B33/14; C; C08; C08G; C08G61/00; C08G61/02; C09; C09K; C09K11/00; C09K11/06; H05B33/10; H10; H10K; H10K50/00; H10K50/10; H10K50/11; H10K50/125; H10K85/00; H10K85/10; H10K85/151; H10K85/111; H10K85/114; Y; Y10; Y10S; Y10S428/00; Y10S428/917; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
229 words
An electroluminescent device comprising: a first charge carrier injecting layer for injecting positive charge carriers; a first layer of a semiconductive conjugated polymer having a band gap selected such that when it is excited radiation at a first wavelength is emitted; a second layer of a semiconductive conjugated polymer having a band gap selected such that when it is excited radiation at a second wavelength is emitted; a second charge carrier injecting layer for injecting negative charge carriers; and means to enable an electric field to be applied across the said layers wherein at least a part of each of the first and second semiconductive conjugated polymer layers is located in an emission zone of the device, the difference between the band gap of the first and second semiconductive conjugated polymer layers being sufficiently small that it does not permit a large build-up of space-charge at an interface between the polymer layers, whereby said emission zone extends for a distance of at least 50 nm over a capture region of the device wherein positive and negative charge carriers combine with one another to form excitons and has a width characteristic of the distance over which said excitons migrate before decaying radiatively, such that on application of an electric field to the device both of said first and second polymer layers are caused to emit radiation at their respective wavelengths.
Claim 2
Dependent Claim
229 words
An electroluminescent device comprising: a first charge carrier injecting layer for injecting positive charge carriers; a first layer of a semiconductive conjugated polymer having a band gap selected such that when it is excited radiation at a first wavelength is emitted; a second layer of a semiconductive conjugated polymer having a band gap selected such that when it is excited radiation at a second wavelength is emitted; a second charge carrier injecting layer for injecting negative charge carriers; and means to enable an electric field to be applied across the said layers wherein at least a part of each of the first and second semiconductive conjugated polymer layers is located in an emission zone of the device, the difference between the band gap of the first and second semiconductive conjugated polymer layers being sufficiently small that it does not permit a large build-up of space-charge at an interface between the polymer layers, whereby said emission zone extends for a distance of at least 50 nm over a capture region of the device wherein positive and negative charge carriers combine with one another to form excitons and has a width characteristic of the distance over which said excitons migrate before decaying radiatively, such that on application of an electric field to the device both of said first and second polymer layers are caused to emit radiation at their respective wavelengths.
Claim 3
Dependent Claim
21 words
An electroluminescent device as claimed in claim 1 wherein the width of the emission zone is not greater than 200 nm.
Claim 4
Dependent Claim
25 words
An electroluminescent device as claimed in claim 1 wherein the first semiconductive conjugated polymer layer has a thickness which is not greater than 50 nm.
Claim 5
Dependent Claim
33 words
An electroluminescent device as claimed in claim 1 wherein there is a third layer of a semiconductive conjugated polymer between said second semiconductive conjugated polymer layer and said second charge carrier injecting layer.
Claim 6
Dependent Claim
20 words
An electroluminescent device as claimed in claim 4 wherein the third layer has a thickness not greater than 50 nm.
Claim 7
Dependent Claim
30 words
An electroluminescent device as claimed in claim 4 wherein the third layer constitutes a barrier layer between the second charge carrier injecting layer and the second semiconductive conjugated polymer layer.
Claim 8
Dependent Claim
15 words
An electroluminescent device as claimed in claim 6 wherein the third layer is light emissive.
Claim 9
Dependent Claim
31 words
An electroluminescent device as claimed in claim 7 wherein there is a further semiconductive conjugated polymer layer between the first semiconductive conjugated polymer layer and the first charge carrier injecting layer.
Claim 10
Dependent Claim
17 words
An electroluminescent device as claimed in claim 8 wherein the second charge carrier injecting layer is calcium.
Claim 11
Dependent Claim
19 words
An electroluminescent device as claimed in claim 9 wherein the first charge carrier injecting layer is indium tin oxide.
Claim 12
Dependent Claim
43 words
An electroluminescent device as claimed in claim 8 wherein the semiconductive conjugated polymers forming any one of the first, second, third and further layers is selected from the group consisting of poly(p-phenylene vinylene); substituted derivatives of poly(p-phenylene vinylene); and copolymers including poly(p-phenylene vinylene).
Claim 13
Dependent Claim
46 words
An electroluminescent device as claimed in claim 11 wherein the copolymer is a conjugated poly(arylene vinylene) copolymer with a proportion of the vinylic groups of the copolymer saturated by the inclusion of a modifier group stable to elimination during formation of a film of the copolymer.
Claim 14
Dependent Claim
19 words
An electroluminescent device as claimed in claim 4 wherein the third layer is a copolymer of PPV and PDMeOPV.
Claim 15
Dependent Claim
29 words
An electroluminescent device as claimed in claim 1 wherein the first semiconductive conjugated polymer layer is a poly(2,5-dialkoxyphenylene-vinylene) selected from the group consisting of MEHPPV, poly(2-methoxy-5-(2-methylpentyloxy)-1,4-phenylenevinylene); poly(2-methoxy-5-pentyloxy-1,4-phenylene-vinylene); and poly(2-methoxy-5-dodecyloxy-1,4-phenylenevinylene).
Claim 16
Dependent Claim
18 words
An electroluminescent device as claimed in claim 1 wherein the first semiconductive conjugated polymer layer is a poly(alkylthienylene).
Claim 17
Dependent Claim
44 words
An electroluminescent device as claimed in claim 1 wherein the first semiconductive conjugated polymer layer is a layer of MEHPPV having a thickness of about 50 nm and the second semiconductive conjugated polymer layer is PPV having a thickness of less than 200 nm.
Claim 18
Dependent Claim
34 words
An electroluminescent device as claimed in claim 16 which includes a barrier layer having a thickness of about 20 nm between the second semiconductive conjugated polymer layer and the second charge carrier injecting layer.
Claim 19
Dependent Claim
43 words
An electroluminescent device as claimed in claim 1 wherein the first semiconductive conjugated polymer layer is a layer of P3DT having a thickness of about 500 nm and the second semiconductive conjugated polymer layer is PPV having a thickness of about 100 nm.
Claim 20
Dependent Claim
24 words
An electroluminescent device as claimed in claim 1 wherein the second polymer layer is PPV of formula ##STR5## where n indicates degree of polymerization.
Claim 21
Independent Claim
205 words
A method of making an electroluminescent device comprising the following steps: providing a first charge carrier injecting layer for injecting positive charge carriers; depositing on said charge carrier injecting layer a first layer of a soluble polymer in a solution of a first solvent and to a first predetermined thickness; drying said first layer; depositing on said first layer a second layer of a polymer to a second predetermined thickness, said second layer of polymer being deposited in the form of a precursor in a solution of a second solvent which is different than the first solvent, the first layer of polymer being insoluble in the second solvent; drying said second layer; heat treating the device so that the precursor is converted to its polymer; depositing a second charge carrier injecting layer for injecting negative charge carriers; wherein the polymer of the first layer emits radiation at a first wavelength when it is excited, and the polymer of the second layer emits radiation at a second wavelength when it is excited; and wherein the first and second predetermined thicknesses are selected so that at least a part of each of the first and second polymer layers is located in an emission zone of the device.
Claim 22
Independent Claim
205 words
A method of making an electroluminescent device comprising the following steps: providing a first charge carrier injecting layer for injecting positive charge carriers; depositing on said charge carrier injecting layer a first layer of a soluble polymer in a solution of a first solvent and to a first predetermined thickness; drying said first layer; depositing on said first layer a second layer of a polymer to a second predetermined thickness, said second layer of polymer being deposited in the form of a precursor in a solution of a second solvent which is different than the first solvent, the first layer of polymer being insoluble in the second solvent; drying said second layer; heat treating the device so that the precursor is converted to its polymer; depositing a second charge carrier injecting layer for injecting negative charge carriers; wherein the polymer of the first layer emits radiation at a first wavelength when it is excited, and the polymer of the second layer emits radiation at a second wavelength when it is excited; and wherein the first and second predetermined thicknesses are selected so that at least a part of each of the first and second polymer layers is located in an emission zone of the device.
References Cited (Backward Citations)
EP0390551A2
Cited
WO1990013148A1
Cited
EP0443861B1
Cited
WO1992003490A1
Cited
WO1992003491A1
Cited
US5283132A
Cited
EP0553950A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-09-14 | 2002-03-16 | 2002-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-09-14 | 2006-03-16 | 2006-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-09-14 | 2010-03-16 | 2010-09-15 | $7700.00 | Window Closed / Lapsed |