Micro electro mechanical system controlled organic LED and pixel arrays and method of using and of manufacturing same

• US 20040007970A1
• Filed: 05/28/2003
• Published: 01/15/2004
• Est. Priority Date: 07/18/2000
• Status: Active Grant

• Current Assignee: Anil Raj Duggal, Ji-Ung Lee, Kelvin Ma
• Original Assignee: Anil Raj Duggal, Ji-Ung Lee, Kelvin Ma
• Inventors: Duggal, Anil Raj, Lee, Ji-Ung, Ma, Kelvin
• Granted Patent: US 6,943,495 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/3216 using a passive matrix
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 59/00 Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00

Abstract

Organic light emitting devices are disclosed that use a micro electromechanical system (MEMS) structure to enable a pixel and pixel array wherein each pixel contains a MEMS and an OLED element. A MEMS structure is used for switching the OLED element. These OLED/MEMS pixels can be fabricated on flex circuit, silicon, as well as other inorganic materials. They can be fabricated in a large array for developing a 2-dimensional display application and each pixel can be addressed through conventional matrix scanning addressing scheme. The ability of fabricating these OLED/MEMS pixels on flexible organic substrates as well as other rigid substrates enables wider selection of substrate materials for use with different applications.

Claims

1. A light emitting element comprising:

an organic light emitting device; and

a micro electromechanical system coupled to the organic light emitting device such that actuation of the micro electromechanical system activates the organic light emitting device to produce light.

2. The light emitting element of claim 1, wherein the organic light emitting device comprises an anode, a cathode, and at least one organic light emitting layer.

3. The light emitting element of claim 2, wherein the micro electromechanical system comprises an actuating member operative to move from a first position in which the organic light emitting device is not activated to a second position in which the organic light emitting device is activated.

4. The light emitting element of claim 3, wherein the actuating member comprises a cantilever.

5. The light emitting element of claim 3, further comprising a first conductive layer disposed on a first side of the actuating member, the first conductive layer operative to force the actuating member toward the organic light emitting device upon application of a voltage between the first conductive layer and the anode of the organic light emitting device.

6. The light emitting element of claim 5, further comprising a second conductive layer disposed on a second side of the organic light emitting device, the second conductive layer operative to supply a current to the organic light emitting device to activate the organic light emitting device to generate light.

7. The light emitting element of claim 3, further comprising a spacing member, adjacent to the actuating member, which spaces the actuating member from an electrical contact.

8. The light emitting element of claim 2, wherein the micro electromechanical system comprises a flexible actuating member, the flexible actuating member comprising:

a first portion which is fixed with respect a contacting surface and spaced from the contacting surface; and

a second portion which can be forced to contact the contacting surface.

9. The light emitting element of claim 8, wherein the contacting surface is a surface of the cathode or the anode of the organic light emitting device.

10. The light emitting element of claim 8, wherein the contacting surface is a surface of a contact which is electrically connected to the cathode or anode of the organic light emitting device.

11. The light emitting element of claim 8, wherein the first portion and the second portion of the actuating member are partially separated by a space to allow the second portion to move toward the contacting surface with respect to the first portion.

12. The light emitting element of claim 11, wherein the first portion occupies a peripheral region of the micro electromechanical system, and the second portion occupies a central region of the micro electromechanical system.

13. The light emitting element of claim 11, wherein the space comprises a plurality of slits which define a spring structure.

14. The light emitting element of claim 1, wherein the micro electromechanical system comprises

a micro electromechanical system substrate;

a contacting member; and

an actuating member;

and wherein the organic light emitting device is deposited directly on the micro electromechanical system substrate;

and wherein the light emitting element further comprises a connecting member electrically connected between the contacting member of the micro electromechanical system and an electrode of the organic light emitting device.

15. The light emitting element of claim 1, wherein the micro electromechanical system comprises

a micro electromechanical system substrate;

a contacting member;

a spacing member; and

an actuating member;

and wherein the organic light emitting device is adhered to the micro electromechanical system substrate;

and wherein the light emitting element further comprises a connecting member electrically connected between the contacting member of the micro electromechanical system and an electrode of the organic light emitting device.

16. The light emitting element of claim 1, wherein the organic light emitting device is formed on a flexible substrate, and the micro electromechanical system is fixed to the flexible substrate.

17. The light emitting element of claim 1, wherein the organic light emitting device is formed on a rigid substrate and the micro electromechanical system is fixed to the rigid substrate.

18. The light emitting element of claim 1 further comprising:

a phosphor layer which absorbs light having a first wavelength from the organic light emitting device and which emits light having a second wavelength.

19. The light emitting element of claim 1, wherein the organic light emitting device and the micro electromechanical system are adapted for use in a flat panel display.

20. The light emitting element of claim 1, wherein the organic light emitting device and the micro electromechanical system are adapted for use in an array of light emitting elements.

21. The light emitting element of claim 1, further comprising a polymeric substrate on which the organic light emitting device is disposed.

22. A method of manufacturing a light emitting element comprising the steps of:

forming an organic light emitting device; and

forming a micro electromechanical system which is coupled to the organic light emitting device such that actuation of the micro electromechanical system activates the organic light emitting device to produce light.

23. The method of claim 22, wherein the organic light emitting device is formed on a substrate, and the micro electromechanical system is formed adjacent to the organic light emitting device such that the micro electromechanical system, when actuated, contacts an electrode of the organic light emitting device to activate the organic light emitting device.

24. A method as recited in claim 22, wherein the step of forming a micro electromechanical system comprises forming a cantilever member operative to move from a first position in which the organic light emitting device is not activated to a second position in which the organic light emitting device is activated.

25. A method as recited in claim 22 wherein the step of forming a micro electromechanical system comprises forming a flexible cantilever portion having a first conductive layer and a second conductive layer and being operative to flex towards an electrical contact when an electric potential is applied to the first conductive layer.

26. A method as recited in claim 22 further comprising the step of forming a layer of phosphor material which receives light from the organic light emitting device.

27. A method of manufacturing a light emitting element comprising the steps of:

providing a micro electromechanical system, the micro electromechanical system comprising;

an actuating member;

a contacting surface; and

a micro electromechanical system substrate;

depositing an organic light emitting device on the micro electromechanical system substrate; and

electrically connecting an electrode of the organic light emitting device to the contacting surface of the micro electromechanical system.

28. A method of manufacturing a light emitting element comprising the steps of:

providing a micro electromechanical system;

the micro electromechanical system comprising;

an actuating member;

a contacting surface; and

a micro electromechanical system substrate;

providing an organic light emitting device;

adhering the organic light emitting device to the micro electromechanical system substrate; and

electrically connecting an electrode of the organic light emitting device to the contacting surface of the micro electromechanical system.

29. A light emitting element comprising:

an organic light emitting device; and

means for electromechanically activating the organic light emitting device.

30. A method for controlling an organic light emitting device comprising the steps of:

generating a control voltage to be applied to the organic light emitting device; and

operating a micro electromechanical system to complete an electrical circuit such that the control voltage activates the organic light emitting device to produce light.

31. The method of claim 30, wherein the operating step comprises applying a voltage between the micro electromechanical system and the organic light emitting device to cause a portion of the micro electromechanical system to move and complete an electrical circuit for supplying current to the organic light emitting device.

32. The method of claim 30, wherein the operating step comprises moving a cantilever member of the micro electromechanical system from a first position in which the organic light emitting device is not activated to a second position in which the organic light emitting device is activated.

33. The method of claim 30, wherein the generating step comprises generating a pulsed signal to be applied to the organic light emitting device as the control voltage.

34. The method of claim 33, further comprising the step of modulating at least one of a width and a height of a pulse of the pulsed signal to control the light output from the organic light emitting device.