Active matrix OED array

• US 5,929,474 A
• Filed: 03/10/1997
• Issued: 07/27/1999
• Est. Priority Date: 03/10/1997
• Status: Expired due to Term

• Current Assignee: Universal Display Corporation
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Lee, Hsing-Chung, Shi, Song Q., Huang, Rong-Ting
• Primary Examiner(s): Abraham, Fetsum
• Application Number:
  US08/814,136
• Time in Patent Office: 869 Days
• Field of Search: 257/79-88, 257/222, 257/233, 257/257, 257/258, 257/290-292, 257/293, 257/114, 257/116, 313/104, 313/425, 313/500, 313/505, 313/506, 313/781, 250/370
• US Class Current: 257/292
• CPC Class Codes: H10K 50/841 Self-supporting sealing arrangements
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals

Abstract

An active matrix OED array includes an array area defined on a semiconductor substrate defining rows and columns of pixels and driver areas spaced from the array area with driver circuits including row drivers coupled to row buses and column drivers coupled to column buses formed in the driver areas. An active control circuit and an OED are formed in each pixel of the array area and coupled to a row and a column bus adjacent each pixel. A second substrate is formed of light transmissive material and includes externally accessible electrical connectors coupled to the driver circuits. The semiconductor substrate includes a first bump pad encircling the array area and the second substrate includes a mating second bump pad with the first and second bump pads engaged to seal the array area.

Claims

1. An active matrix organic light emitting device array comprising:

a semiconductor substrate having an array area defined thereon;

a plurality of field effect transistors, each including first and second current carrying terminals and a control terminal, formed in the array area on the semiconductor substrate in rows and columns, each of the rows including a row bus coupled to the first current carrying terminal of each field effect transistor in the row, and each of the columns including a column bus coupled to the control terminal of each field effect transistor in the column;

a planarizing layer of insulating material positioned over the plurality of field effect transistors in the array area and defining a substantially planar surface;

a plurality of contact pads formed on the planar surface of the planarizing layer in the array area in rows and columns, each contact pad of the plurality of contact pads associated with one field effect transistor of the plurality of field effect transistors and coupled to the second current carrying terminal of the associated field effect transistor by a conductor formed through the planar layer;

a plurality of layers of organic material sequentially formed in overlying relationship on the contact pads in the array area so as to define an organic light emitting device on each contact pad with each contact pad operating as a first terminal of an overlying organic light emitting device; and

electrical and light conducting material positioned in overlying relationship over the layers of organic material in the array area and operating as a common second terminal of the organic light emitting devices.

2. An active matrix organic light emitting device array as claimed in claim 1 wherein the semiconductor substrate includes one of silicon, GaAs, SiC, and sapphire.

3. An active matrix organic light emitting device array as claimed in claim 1 wherein the plurality of field effect transistors includes MOSFETs.

4. An active matrix organic light emitting device array as claimed in claim 1 wherein each of the plurality of contact pads is coupled to the second current carrying terminal of the associated field effect transistor by a feedthrough connection through the planarizing layer of insulating material.

5. An active matrix organic light emitting device array as claimed in claim 1 wherein the plurality of layers of organic material includes an electron transporting layer, a light emitting layer and a hole transporting layer sequentially formed in overlying relationship.

6. An active matrix organic light emitting device array as claimed in claim 1 wherein the planarizing layer of insulating material includes SiO₂.

7. An active matrix organic light emitting device array as claimed in claim 1 wherein the plurality of contact pads include aluminum.

8. An active matrix organic light emitting device array as claimed in claim 7 wherein the first current carrying terminal of each of the field effect transistors is a drain, the second current carrying terminal of each of the field effect transistors is a source, and the control terminal of each of the field effect transistors is a gate.

9. An active matrix organic light emitting device array as claimed in claim 8 wherein the first terminal of each of the overlying organic light emitting devices is a cathode.

10. An active matrix organic light emitting device array as claimed in claim 9 wherein the common second terminal includes a thin layer of gold and a layer of indium-tin-oxide.

11. An active matrix organic light emitting device array as claimed in claim 8 wherein the first terminal of each of the overlying organic light emitting devices is an anode and includes a layer of indium-tin-oxide positioned between the aluminum contact pad and the plurality of layers of organic material.

12. An active matrix organic light emitting device array as claimed in claim 11 wherein the common second terminal includes a thin layer of one of magnesium and lithium-silver and a layer of indium-tin-oxide sequentially formed in overlying relationship.

13. An active matrix organic light emitting device array as claimed in claim 1 wherein the semiconductor substrate further has driver areas defined thereon with CMOS driver circuits formed on the substrate.

14. An active matrix organic light emitting device array as claimed in claim 13 wherein the CMOS driver circuits include row drivers coupled to the row buses and column drivers coupled to the column buses.

15. An active matrix organic light emitting device array as claimed in claim 14 including in addition a second substrate formed of light transmissive material bonded to the semiconductor substrate in overlying relationship so as to encapsulate the array area.

16. An active matrix organic light emitting device array as claimed in claim 15 wherein the second substrate includes externally accessible electrical connectors coupled to the CMOS driver circuits.

17. An active matrix organic light emitting device array as claimed in claim 16 wherein the externally accessible electrical connectors are bump bonded to the CMOS driver circuits, a first bump pad encircles the array area on the semiconductor substrate and a mating bump pad is formed on the second substrate with the first and second bump pads engaged to seal the array area.

18. An active matrix organic light emitting device array comprising:

a semiconductor substrate having an array area defined thereon, the array area defining rows and columns of pixels, the semiconductor substrate further having driver areas defined thereon and spaced from the array area with driver circuits formed on the semiconductor substrate in the driver areas, the driver circuits including row drivers coupled to row buses in the array area and column drivers coupled to column buses in the array area;

a plurality of active control circuits formed in the array area one each associated with each pixel in the array area and a plurality of organic light emitting devices formed in the array area so as to define an organic light emitting device in each pixel, each of the active control circuits positioned between the semiconductor substrate and one of the organic light emitting devices, the active control circuit associated with each pixel being coupled between the organic light emitting device associated with the respective pixal and a row and column bus adjacent each pixel; and

a second substrate formed of light transmissive material and including externally accessible electrical connectors coupled to the driver circuits, the semiconductor substrate including a first bump pad encircling the array area and the second substrate including a mating second bump pad with the first and second bump pads engaged to seal the array area.

19. An active matrix organic light emitting device array as claimed in claim 18 wherein the externally accessible electrical connectors are bump bonded to the driver circuits.

20. An active matrix organic light emitting device array as claimed in claim 18 wherein the plurality of active control circuits each include a field effect transistor.

21. An active matrix organic light emitting device array as claimed in claim 18 wherein the driver circuits each include a CMOS circuit.

22. An active matrix organic light emitting device array as claimed in claim 18 wherein the plurality of organic light emitting devices include:

a planarizing layer of insulating material positioned over the plurality of active control circuits in the array area and defining a substantially planar surface;

a plurality of contact pads formed on the planar surface of the planarizing layer in the array area in rows and columns, one contact pad associated with each pixel and coupled between the active control circuit and the organic light emitting device associated with the pixel; and

a plurality of layers of organic material sequentially formed in overlying relationship on the contact pads in the array area so as to define an organic light emitting device on each contact pad with each contact pad operating as a first terminal of an overlying organic light emitting device.