Light-emitting devices

• US 20030076454A1
• Filed: 11/11/2002
• Published: 04/24/2003
• Est. Priority Date: 05/17/2000
• Status: Active Grant

• Current Assignee: IPIFS Guarantee Corp.
• Original Assignee: IPIFS Guarantee Corp.
• Inventors: Burroughes, Jeremy Henley
• Granted Patent: US 6,828,724 B2
• Time in Patent Office: Days
• US Class Current: 349/61
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 59/35 comprising red-green-blue [RGB] subpixels

Abstract

A light-emitting device comprising a first electroluminescent element for emitting light of a first colour when energised and a second electroluminescent element for emitting light of a second colour when energised, characterised in that dimensions of the first and second elements and any spacing therebetween are selected to create an overall impression of a single light source when simultaneously energised and viewed as intended.

Claims

1. A light-emitting device comprising a first electroluminescent element for emitting light of a first colour when energised and a second electroluminescent element for emitting light of a second colour when energised, characterised in that dimensions of the first and second elements and any spacing therebetween are selected to create an overall impression of a single light source when simultaneously energised and viewed as intended.

2. A light-emitting device according to claim 1, further comprising means, common to both elements, for energising the elements.

3. A light-emitting device according to claim 1 or 2, in which at least one of the electroluminescent elements comprises an organic light-emissive material.

4. A light-emitting device according to claim 1, 2 or 3, in which the first electroluminescent element is one of a plurality of such elements for emitting light of the first colour when energised, the plurality of first-light-emitting elements being arranged in a first spaced-apart array.

5. A light emitting device according to any one of claims 1 to 4, in which the second electroluminescent element is one of a plurality of such elements for emitting light of the second colour when energised, the plurality of second-light-emitting elements being arranged in a second spaced-apart array.

6. A light emitting device according to claim 5 when appendent to claim 4, in which each element of the first spaced-apart array is adjacent to, or disposed between elements of the second spaced-apart array.

7. A light emitting device according to any one of claims 1 to 6, in which dimensions of the elements and any spacings between adjacent elements are unresolvable to the naked eye.

8. A light emitting device according to any one of claims 1 to 7, in which the elements are disposed on a substrate.

9. A light emitting device according to claim 8 in which maximum dimensions of the elements over the surface of the substrate is less than 5.0×

10<sup>−

6</sup> m.

10. A light emitting device according to claim 8 or 9, in which the maximum spacing between adjacent elements over the surface of the substrate is less than 5.0×

10<sup>−

6</sup> m.

11. A light emitting device according to any one of claims 1 to 10, in which the first and second colours of light emitted by the first and second elements are selected from the group consisting of red, green and blue.

12. A light emitting device according to any one of claims 1 to 11, further comprising a third electroluminescent element for emitting light of a third colour when energised, the dimensions of the third element and any spacing between the third and adjacent elements being selected to create the impression of a single light source when all the elements are energised and viewed as intended.

13. A light emitting device according to claim 12, in which the first, second and third electroluminescent elements are selected to produce red, green and blue light emissions respectively.

14. A light emitting device according to any one of the preceding claims, in which the single light source is perceived to produce substantially white light.

15. A light emitting device according to claim 14, in which the substantially white light has a hue dependent upon the relative proportions of the elements.

16. A light emitting device according to any one of claims 3 to 15, in which the organic light-emissive materials in the at least one element is deposited by a process of ink-jet deposition.

17. A light emitting device according to any one of claims 1 to 16, in which the first and second elements are energised by a pair of common electrodes.

18. An electronic device comprising an LCD display and a backlight, the backlight comprising a light-emitting device according to any one of claims 1 to 17.

19. A method of manufacturing a light-emitting device, comprising:

providing a first electroluminescent element for emitting light of a first colour when energised;

providing a second electroluminescent element for emitting light of a second colour when energised;

characterised by;

selecting dimensions of the first and second elements and any spacing therebetween to create an overall impression of a single light source when simultaneously energised and viewed as intended.

20. A method according to claim 19, further comprising providing means, common to both elements, for energising the elements.

21. A method according to claim 19 or 20, further comprising providing a plurality of electroluminescent elements for emitting light of the first colour when energised, the plurality of first-colour-light emitting elements being arranged in a spaced-apart array with the first electroluminescent element.

22. A method according to claim 19, 20 or 21, further comprising providing a plurality of electroluminescent elements for emitting light of the second colour when energised, the plurality of second-colour-light emitting elements being arranged in a spaced-apart array with the second electroluminescent element.

23. A method according to claim 22 when appendent to claim 21, in which the first electroluminescent element is adjacent or disposed between second-colour-light emitting elements.

24. A method according to any one of claims 19 to 23, in which at least one of the electroluminescent elements comprises an organic light-emissive material.

25. A method according to claim 24, further comprising depositing the organic light-emissive material by a process of ink-jet deposition.

26. A method according to claim 25, in which the deposited organic light-emissive material comprises at least one dot having a maximum dimension of 5.0×

10<sup>−

6</sup> m.

27. A light emitting device substantially as hereinbefore described with reference to and as illustrated in the accompanying FIGS. 2-5.

28. A method of manufacturing a light-emitting device substantially as hereinbefore described with reference to and as illustrated in the accompanying FIGS. 2-5.