HIGH RESOLUTION PIXEL ARCHITECTURE

• US 20130112960A1
• Filed: 12/21/2012
• Published: 05/09/2013
• Est. Priority Date: 12/01/2009
• Status: Active Grant

• Current Assignee: IGNIS Innovation Incorporated
• Original Assignee: IGNIS Innovation Incorporated
• Inventors: Chaji, Gholamreza, Gupta, Vasudha, Nathan, Arokia
• Granted Patent: US 8,803,417 B2
• Time in Patent Office: Days
• US Class Current: 257/40
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0439 Pixel structures
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: H01L 27/15 including semiconductor components having potential barriers, specially adapted for light emission
• CPC Class Codes: H01L 33/00 Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof H10K50/00 takes precedence; devices consisting of a plurality of semiconductor components formed in or on a common substrate and including semiconductor components having potential barriers, specially adapted for light emission H01L27/15; semiconductor lasers H01S5/00
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H10K 50/00 Organic light-emitting devices integrated devices or assemblies of multiple devices H10K59/00, H10K65/00; organic semiconductor lasers H01S5/36
• CPC Class Codes: H10K 50/856 comprising reflective means
• CPC Class Codes: H10K 59/121 characterised by the geometry or disposition of pixel elements
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/35 comprising red-green-blue [RGB] subpixels
• CPC Class Codes: H10K 59/351 comprising more than three subpixels, e.g. red-green-blue-white [RGBW]
• CPC Class Codes: H10K 59/352 the areas of the RGB subpixels being different
• CPC Class Codes: H10K 59/353 characterised by the geometrical arrangement of the RGB subpixels
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass

Abstract

A pixel structure comprises a substantially transparent substrate, a drive transistor formed on the substrate, an organic light emitting device formed on the opposite side of the drive transistor from the substrate, a reflective layer disposed between the light emitting device and the drive transistor and having a reflective surface facing the light emitting device. The reflective layer forms an opening offset from the drive transistor for passing light emitted by the light emitting device to the substrate. At least a portion of the reflective layer is preferably concave in shape to direct reflected light from the light emitting device back onto the light-emitting device.

Claims

1. A pixel structure comprising

a substantially transparent substrate,

a drive transistor formed on said substrate,

an organic light emitting device formed on the opposite side of said drive transistor from said substrate,

a reflective layer disposed between said light emitting device and said drive transistor and having a reflective surface facing said light emitting device, said reflective layer forming an opening offset from said drive transistor for passing light emitted by said light emitting device to said substrate.

2. The pixel structure of claim 1 in which at least a portion of the reflective layer is concave in shape to direct reflected light from said light emitting device back onto said light-emitting device.

3. A pixel structure comprising

a substrate;

a first photoresist layer having a first opening over the substrate;

a reflective layer having a second opening, the reflective layer covering the first photoresist layer;

a second photoresist layer in the second opening and over the reflective layer; and

an organic light emitting device formed over the second photoresist layer,

wherein the second opening overlaps with the first opening, and at least a portion of the reflective layer is concave in shape.

4. The pixel structure of claim 3, further comprising

a drive transistor between the substrate and the first photoresist layer,

wherein the drive transistor controls the luminance of the organic light emitting device.

5. The pixel structure of claim 3, wherein the reflective layer comprises aluminum.

6. The pixel structure of claim 3, wherein the organic light emitting device comprises

an anode layer over the second photoresist layer;

an organic electroluminescent layer over the anode layer; and

a cathode layer over the organic electroluminescent layer.

7. The pixel structure of claim 6, further comprising a common electrode layer over the cathode layer.

8. The pixel structure of claim 3, wherein the reflective layer has a reflective surface facing the organic light emitting device, and directing light from the organic light emitting device to the second opening.

9. A method of forming a pixel structure, the method comprising

providing a substrate;

forming a first photoresist layer having a first opening over the substrate;

forming a reflective layer having a second opening, the reflective layer covering the first photoresist layer;

forming a second photoresist layer in the second opening and over the reflective layer; and

forming an organic light emitting device over the second photoresist layer,

wherein the second opening overlaps with the first opening, and

wherein at least a portion of the reflective layer is concave in shape.

10. The method of claim 9, wherein the step of forming the first photoresist layer comprises

depositing the first photoresist layer on the substrate;

forming a first mask layer on the first photoresist layer;

depositing a third photoresist layer on the first mask layer;

forming a second mask layer on the third photoresist layer;

applying ultraviolet radiation to the second mask layer, thereby separating the third photoresist layer;

removing the second mask layer;

etching the first mask layer with the third photoresist layer, thereby separating the first mask layer;

removing the third photoresist layer;

etching the first photoresist layer with the first mask layer, thereby forming the first opening; and

removing the first mask layer.

11. The method of claim 9, wherein the step of forming the reflective layer comprises:

depositing the reflective layer on the first photoresist layer and the substrate;

depositing a third photoresist layer on the reflective layer;

applying ultraviolet radiation to the third photoresist layer;

developing the third photoresist layer;

etching the reflective layer with the third photoresist layer, thereby forming the second opening; and

removing the third photoresist layer.

12. The method of claim 9, further comprising:

forming a drive transistor over the substrate, wherein the drive transistor controls the luminance of the organic light emitting device.

13. The method of claim 9, wherein the reflective layer has a reflective surface facing the organic light emitting device, and directing light from the organic light emitting device toward the second opening.