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

• US 6,943,495 B2
• Filed: 05/28/2003
• Issued: 09/13/2005
• Est. Priority Date: 07/18/2000
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Duggal, Anil Raj, Lee, Ji-Ung, Ma, Kelvin
• Primary Examiner(s): Guharay, Karabi
• Application Number:
  US10/447,244
• Publication Number:
  US 20040007970A1
• Time in Patent Office: 839 Days
• Field of Search: 313504-506, 313/500, 313/502, 313/509, 428/690, 428/917, 315/169.3, 315/169.1, 200/512, 200/514, 200/314
• 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 comprising an anode, a cathode, and an organic light emitting material disposed between the anode and the cathode; 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;

wherein the micro electromechanical system comprises a first conductive layer, a second conductive layer, and an actuating member sandwiched between the first conductive layer and the second conductive layer;

the micro electromechanical system forms a cantilever extending over the cathode of the organic light emitting device and is spaced apart therefrom when the micro electromechanical system is in an unactuated state; and

the micro electromechanical system is actuated by a voltage applied across the anode and the first conductive layer.

2. The light emitting element of claim 1, wherein the actuating member is 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.

3. The light emitting element of claim 2, the first conductive layer is disposed on a first side of the actuating member and the second conductive layer is disposed on a second side of the actuating member, the first conductive layer electromechanically operative to force the actuating member toward the organic light emitting device upon application of voltage between the first conductive layer and the anode of the organic light emitting device and 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.

4. The light emitting element of claim 2, further comprising a spacing member, adjacent to the actuating member, which spaces the actuating member from an electrical contact.

5. The light emitting element of claim 1, 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.

6. The light emitting element of claim 5, 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.

7. The light emitting element of claim 5, 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.

8. The light emitting element of claim 7, 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.

9. 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.

10. 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.

11. 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.

12. 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.

13. 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.

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

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

forming an organic light emitting device by disposing an organic light emitting material between an anode and a cathode; and

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

said forming the micro electromechanical system comprising;

forming a cantilever that comprises an actuating member sandwiched between a first conductive layer and a second conductive layer; and

disposing the cantilever over the cathode of the organic light emitting device such that upon the electrical actuation of the micro electromechanical system, one of the conductive layers of the cantilever makes an electrical contact with an electrode of the organic light emitting device.

16. The method of claim 15, 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.

17. The method as recited in claim 15, 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.

18. The method as recited in claim 15, 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.

19. The method as recited in claim 15, further comprising the step of forming a layer of phosphor material which receives light from the organic light emitting device.

20. A light emitting element comprising:

an organic light emitting device comprising an organic light emitting material disposed between an anode and a cathode; and

a structure comprising an electrically conductive material for electromechanically activating the organic light emitting device;

said structure forming a cantilever and being disposed to extend over the cathode of the organic light emitting device and to be spaced apart therefrom when said structure is in an unactuated state; and

said electrically conductive material of said structure in an actuated state making an electrical contact with an electrode of said organic light emitting device.