Organic light active devices with particulated light active material in a carrier matrix

• US 20040097005A1
• Filed: 02/26/2003
• Published: 05/20/2004
• Est. Priority Date: 11/19/2002
• Status: Active Grant

• Current Assignee: John James Daniels
• Original Assignee: John James Daniels
• Inventors: Daniels, John James
• Granted Patent: US 7,256,427 B2
• Time in Patent Office: Days
• US Class Current: 438/99
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/148 Charge coupled imagers individual charge coupled devices H01L29/765
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/182 OLED comprising a fiber structure
• CPC Class Codes: H10K 50/80 Constructional details
• CPC Class Codes: H10K 59/13 comprising photosensors that control luminance
• CPC Class Codes: H10K 59/32 Stacked devices having two or more layers, each emitting at different wavelengths
• CPC Class Codes: H10K 71/12 using liquid deposition, e.g. spin coating
• CPC Class Codes: H10K 71/13 using printing techniques, e.g. ink-jet printing or screen printing

Abstract

A light active device includes a semiconductor particulate dispersed within a carrier material. A first contact layer is provided so that on application of an electric field charge carriers having a polarity are injected into the semiconductor particulate through the conductive carrier material. A second contact layer is provided so that on application of the electric field to the second contact layer charge carriers having an opposite polarity are injected into the semiconductor particulate through the conductive carrier material. The semiconductor particulate comprises at least one of an organic and an inorganic semiconductor. The semiconductor particulate may comprise an organic light active particulate that includes at least one conjugated polymer. When an electric field is applied between the first and second contact layers to the semiconductor particulate through the conductive carrier material, the second contact layer becomes positive relative to the first contact layer and charge carriers of opposite polarity are injected into the semiconductor particulate. The opposite polarity charge carriers combine to form in the conjugated polymer charge carrier pairs which decay radiatively so that radiation is emitted from the conjugated polymer. In this case, the inventive light active device acts as a light emitting diode.

Claims

1. A light active device comprising:

a semiconductor particulate dispersed within a conductive carrier material;

a first contact layer which is selected so that on application of an electric field to the first contact layer charge carriers of a first type are injected into the semiconductor particulate through the conductive carrier material; and

a second contact layer which is selected so that on application of an electric field to the second contact layer charge carriers of a second type are injected into the semiconductor particulate through the conductive carrier material.

2. A light active device according to claim 1;

wherein the semiconductor particulate comprises at least one of an organic and an inorganic semiconductor.

3. A light active device according to claim 1;

wherein the semiconductor particulate comprises an organic light active particulate including at least one conjugated polymer, said at least one conjugated polymer having a sufficiently low concentration of extrinsic charge carriers so that on applying an electric field between the first and second contact layers to the semiconductor particulate through the conductive carrier material the second contact layer becomes positive relative to the first contact layer and charge carriers of said first and second types are injected into the semiconductor particulate and combine to form in the conjugated polymer charge carrier pairs which decay radiatively so that radiation is emitted from the conjugated polymer.

4. A light active device according to claim 3;

wherein the organic light active particulate comprises particles including at least one of hole transport material, organic emitters, and electron transport material.

5. An organic light active device according to claim 3;

wherein the organic light active particulate comprises particles including a polymer blend, the polymer blend including an organic emitter blended with at least one of a hole transport material, an electron transport material and a blocking material.

6. An organic light active device according to claim 3;

wherein the organic light active particulate comprises microcapsules including a polymer shell encapsulating an internal phase comprised of a polymer blend including an organic emitter blended with at least one of a hole transport material, an electron transport material and a blocking material.

7. An organic light active device according to claim 3;

wherein the conductive carrier material comprises a binder material with one or more characteristic controlling additives.

8. An organic light active device according to claim 7;

wherein the characteristic controlling additives are at least one of a particulate and a fluid include a dessicant;

a conductive phase, a semiconductive phase, an insulative phase, a mechanical strength enhancing phase, an adhesive enhancing phase, a hole injecting material, an electron injecting material, a low work metal, a blocking material, and an emission enhancing material.

9. An organic light active device according to claim 1;

wherein the first contact layer and the second contact layer are arranged to form an array of pixels, each pixel including a portion of the semiconductor particulate dispersed within the conductive carrier material, each pixel being selectively addressable by applying a driving voltage to the first contact layer and the second contact layer.

10. A voltage controlled light active device for emitting two or more colors of light, comprising:

a first electrode;

a second electrode disposed adjacent to the first electrode and defining a gap therebetween;

a light active layer comprised of a mixture of a light active particulate and a conductive carrier material, said mixture being disposed within said gap, said light active particulate comprised of first emitting particles including a first electroluminescent conjugated polymer, the first emitting particles emitting a number of photons of a first color in response to a first turn-on voltage applied to the electrodes and emitting a different number of photons of the first color in response to other turn-on voltages, said light active particulate further comprised of second emitting particles, the second emitting particles emitting a number of photons of a second color in response to a second turn-on voltage and a different number of photons of the second color in response to other turn-on voltages.

11. A voltage controlled organic light active device according to claim 10;

wherein the second emitting particles includes at least one of a second conjugated polymer and an inorganic emitting material.

12. A voltage controlled organic light active device according to claim 10;

wherein the light active layer further comprises third emitting particles, the third emitting particles emitting a number of photons of a third color in response to a third turn-on voltage applied to the electrodes and a different number of photons of the third color in response to other turn-on voltages.

13. A voltage controlled organic light active device according to claim 12;

wherein the first color is red;

the second color is green and the third color is blue.

14. A voltage controlled light active device according to claim 12;

wherein the light active layer further comprises at least one additional emitting particles containing another electroluminescent conjugated polymer or inorganic emitter, said at least one additional emitting particles emitting a number of photons of a color in response to a turn-on voltage and a different number of photons in response to other turn-on voltages.

15. A voltage controlled organic light active device according to claim 14;

wherein the color is within the visible spectrum.

16. A voltage controlled organic light active device according to claim 14;

wherein the color is not within the visible spectrum.

17. A voltage controlled organic light active device according to claim 14;

wherein the color is infra-red.

18. A voltage controlled organic light active device according to claim 10;

wherein the first electrode is part of an x-grid of electrodes and the second electrode is part of a y-grid of electrodes and the mixture of the organic light active particulate and the conductive carrier material in the gap between the first electrode and the second electrode make up an emissive component of a pixel of a display device.

19. A voltage controlled organic light active device according to claim 10;

wherein the at least one electroluminescent conjugated polymer includes a plurality of members selected from the group consisting of polythiophenes, poly(paraphenylenes), and poly(paraphenylene vinylene), at least some of said members having substituents selected from the group ocnsisting of alkyl, alkoxy, cycloalkyl, cycloalkoxy, flouroalkyl, alkylphenylene, and alkoxyphenylene vinylene.

20. An organic light active display device, comprising:

a substrate;

a first grid of driving electrodes formed on the substrate;

a second grid of electrodes disposed adjacent to the first grid of electrodes and defining a gap therebetween;

a mixture of an organic light active particulate and a conductive carrier material, said mixture being disposed within said gap, said organic light active particulate comprised of first particles including a first electroluminescent conjugated polymer having a first turn-on voltage and second particles including a second electroluminescent conjugated polymer having a second turn-on voltage different than the first turn-on voltage, wherein light having a first color is emitted by the first electroluminescent conjugated polymer in response to the first turn-on voltage applied to the first electrode and the second electrode and light having a second color is emitted by the second electroluminescent conjugated polymer in response to the second turn-on voltage applied to the first electrode and the second electrode.

21. A method of forming a layered organic light active material particulate, comprising the steps of:

forming a first mixture of a first organic light active component material and a first carrier fluid;

forming a second mixture of a second organic light active component material and a second carrier fluid;

generating a first mist of the first mixture in an environment so that a first particulate of the first organic light active component material is temporarily suspended in the environment;

generating a second mist of the second mixture in the environment so that a second particulate of the second organic light active component material is temporarily suspended in the environment; and

allowing the first particulate and the second particulate to commingle and attract together in the environment to form a first layered organic light active material particulate comprising a first layer of the first organic light active component material and a second layer of the second organic light active component material.

22. A method of forming a layered organic light active material particulate according to claim 21;

further comprising the steps of;

forming a third mixture of a third organic light active component material and a third carrier fluid;

forming a fourth mixture of the first layered organic light active material particulate and a fourth carrier fluid;

generating a third mist of the third mixture in an environment so that a third particulate of the third organic light active component material is temporarily suspended in the environment;

generating a fourth mist of the fourth mixture in the environment so that the first layered organic light active material particulate is temporarily suspended in the environment; and

allowing the third particulate and the first layered organic light active material particulate to commingle and attract together in the environment to form a second layered organic light active material particulate comprising a layer of the first layered organic light active material particulate and a layer of the third organic light active component material.

23. A method of forming a layered organic light active material particulate according to claim 22;

further comprising the steps of;

forming another mixture of another organic light active component material and another carrier fluid;

forming yet another mixture of a previously formed layered organic light active material particulate and yet another carrier fluid;

generating another mist of said another mixture in an environment so that another particulate of said another organic light active component material is temporarily suspended in the environment;

generating yet another mist of said yet another mixture in the environment so that the first layered organic light active material particulate is temporarily suspended in the environment; and

allowing said another particulate and the previously formed layered organic light active material particulate to commingle and attract together in the environment to form a second layered organic light active material particulate comprising a layer of the first layered organic light active material particulate and a layer of the third organic light active component material.

24. A method of forming a layered organic light active material particulate according to claim 23;

wherein at least one of the first, second and subsequent organic active component material comprises at least one of a hole transport material, an emission layer material, an electron transport material, and a blocking material.

25. A method of forming a layered organic light active material particulate according to claim 24;

wherein at least another one of the first, second and subsequent organic active component material comprises at least one of a magnetic material, an electrostatic material, a desiccant, hole injecting material, and an electron injecting material.

26. A method of forming a layered organic light active material particulate according to claim 23;

wherein at least one of the first and the second and subsequent carrier fluids is a first solvent and the respective first, second and subsequent organic light active component material is soluble in the solvent.

27. A method of forming a layered organic light active material particulate according to claim 26;

wherein at least one of the first, second and subsequent organic light active component material is a fine particulate insoluble in the respective first, second and subsequent carrier fluids.

28. A method of forming a layered organic light active material particulate according to claim 22;

wherein the third organic light active particulate comprises a multi-layered organic light active material particulate.

29. A method of forming a layered organic light active material particulate according to claim 21;

wherein the environment comprises one of a gas mixture, an inert gas, a liquid or a vacuum.

31. A method of forming a layered organic light active material particulate according to claim 21;

further comprising the step of microencapsulating the organic light active material particulate.

32. A method of forming a layered organic light active material particulate according to claim 21;

further comprising the steps of forming the first mist with a charge have a polarity; and

forming the second mist with a charge having an opposite polarity so that the electrical attraction is enhanced between the first organic light active particulate and the second organic light active particulate.

30. A method of forming a layered organic light active material particulate according to claim 30;

further comprising the step of performing a characteristic enhancing treatment to the formed layered organic light active material particulate.

33. A method for driving a multi-color light emitting device, the multi-color light emitting device capable of emitting two or more colors in sequence, each color being emitted in response to a respective different applied turn-on voltage, comprising the steps of:

during an emission cycle applying a first turn-on voltage having a duration to the light emitting device so that a first burst of a predominant number of photons of a first color are emitted;

during the emission cycle applying a second turn-on voltage having a duration and at least one of a magnitude and a polarity different than a magnitude and polarity of the first turn-on voltage so that a second burst of a predominant number of photons of a second color are emitted, whereby during the emission cycle the first burst and the second burst occur in rapid succession and a human eye receiving the first burst and the second burst is stimulated to perceive a color different than the first color and the second color.

34. A method of driving a multi-color light emitting device according to claim 33;

further comprising the step of during the emission cycle applying a third turn-on voltage having a duration and at least one of a magnitude and a polarity different than the magnitude and polarity of the other turn-on voltages so that a third burst of a predominant number of photons of a third color are emitted, whereby during the emission cycle the first burst, the second burst and the third burst occur in rapid succession and the human eye receiving the bursts is stimulated to perceive a color different than the first color, the second color and the third color.

35. A method of driving a multi-color light emitting device according to claim 34;

wherein the first color is in the red portion of the visible spectrum, the second color is in the green portion of the visible spectrum and the third color is in the blue portion of the visible spectrum and the light emitting device is controlled so that the number of photons of each color emitted during each burst of the emission cycle results in a predetermined color within the visible spectrum that is not necessarily red, blue or green.

36. A method of driving a multi-color light emitting device according to claim 35;

wherein an intensity, duration and color emitted by the multi-color light emitting device is adjusted according to a retinex display operation.

37. A method of driving a multi-color light emitting device according to claim 36;

wherein the retinex display operation comprises the steps of providing digital data indexed to represent positions on a display, said digital data being indicative of an intensity for each position in each spectral band;

adjusting the intensity of each position in each spectral band to generate an adjusted intensity value in accordance with a predetermined mathematical equation, filtering the adjusted intensity value for each position with a common function; and

controlling turn-on voltages so that the emission of photons of each color is based on the adjusted intensity value for each filtered spectral for each position.