Article comprising microcavity light sources

Apparatus according to the invention comprises at least two optical microcavity light emitters. Each one of the at least two light emitters comprises spaced apart reflectors that define a microcavity, and further comprises organic material that is capable of electro-luminescence (e.g., tris (8-hydroxyquinolinol) aluminum, commonly referred to as "Alq"), and means for applying an electric field across the organic material. One of the at least two microcavities has effective optical length L.sub.1, and the other microcavity has effective optical length L.sub.2 .noteq.L.sub.1, with the optical lengths selected such that one of the microcavities emits radiation of a first color (e.g., red), and the other microcavity emits radiation of a second color (e.g., green). In many cases there will be present also a third microcavity that emits radiation of a third color (e.g., blue). In preferred embodiments there is present within the microcavities a filler layer, of thickness selected to provide to a given microcavity the desired optical length. A preferred embodiment of the invention is a full color flat panel display that comprises many pixels, each pixel comprising at least three different microcavity emitters. Other contemplated embodiments are a LED printer, an optical interconnect and an optical fiber communication system.

We claim:

1. An article comprising a layer structure on a major surface of a substrate body, said layer structure comprising

a) spaced apart first and second reflector means and an active layer that comprises organic material capable of electroluminescence, with at least a first portion of the active layer between said reflector means, said first and second reflector means defining a first microcavity of effective optical length L.sub.1 ; and

b) means that facilitate application of an electric field across the first portion of the active layer such that the first microcavity can be caused to emit radiation of a first color;

CHARACTERIZED IN THAT the layer structure further comprises

c) spaced apart third and fourth reflector means, with a second portion of the active layer between said third and fourth reflector means, said third and fourth reflector means defining a second microcavity of effective optical length L.sub.2 different from L.sub.1 and spaced apart from the first microcavity; and

d) means that facilitate application of an electric field across the second portion of the active layer, such that the second microcavity can be caused to emit radiation of a second color different from the first color.

2. Article according to claim 1, wherein L.sub.1 is approximately equal to one wavelength of the radiation of the first color in the microcavity.

3. Article according to claim 1, wherein each of said first and third reflector means is a portion of a unitary multilayer dielectric mirror, and each of said second and fourth reflector means is a separate portion of a patterned metal layer.

4. Article according to claim 1, wherein the layer structure comprises a filler material of thickness t.sub.f,1 disposed between said first and second reflector means.

5. Article according to claim 4, wherein the layer structure further comprises filler material of thickness t.sub.f,2 .noteq.t.sub.f,1 disposed between said third and fourth reflector means.

6. Article according to claim 1, wherein the layer structure further comprises a hole transport layer or an electron transport layer.

7. Article according to claim 3, wherein the layer structure further comprises a scattering layer disposed outside of said first and second microcavities.

8. Article according to claim 1, further comprising a third microcavity of effective optical length L.sub.3 that differs from L.sub.2 and L.sub.1, said third microcavity being adapted for emission of radiation of a third color.

9. Article according to claim 1, wherein the article comprises a multiplicity of microcavities of effective optical length essentially equal to L.sub.1, and a further multiplicity of microcavities of effective optical length essentially equal to L.sub.2.

10. Article according to claim 9, wherein the article comprises a further multiplicity of microcavities of effective optical length essentially equal to L.sub.3, said article being a tri-color display.

11. An article according to claim 3, wherein the organic material capable of electroluminescence is selected from the group consisting of Alq, perylene derivatives, anthracene, poly(phenylene vinylenes), oxadiazole or stilbene derivatives, and any of the foregoing doped with a dopant selected from the group consisting of coumarines, DCM, and rhodamine derivatives; wherein the multilayer dielectric mirror comprises alternating layers of SiO.sub.2 and SiN.sub.x, with x selected to give a refractive index of about 2.2, or SiO.sub.2 and TiO.sub.2 ; wherein the patterned metal layer comprises Al, Ag, Au, alloys of Mg and Ag, or alloys of Mg and Al; wherein said means for applying an electric field across said first and second portions of the active layer comprise indium tin oxide or polyaniline; and wherein the layer structure comprises a scattering layer disposed outside of said first and second microcavities.

12. An article according to claim 1, wherein the article is a flat panel display, optical interconnect means, optical fiber communication means, or LED printing means.

13. Article according to claim 6, wherein the layer structure comprises a hole transport layer and an electron transport layer.