Micro-lens arrays for display intensity enhancement

• US 6,984,934 B2
• Filed: 07/09/2002
• Issued: 01/10/2006
• Est. Priority Date: 07/10/2001
• Status: Expired due to Term

• Current Assignee: The Trustees of Princeton University (Princeton University)
• Original Assignee: The Trustees of Princeton University (Princeton University)
• Inventors: Forrest, Stephen R., Möller, Sven
• Primary Examiner(s): WILLIAMS, JOSEPH L
• Application Number:
  US10/191,306
• Publication Number:
  US 20030020399A1
• Time in Patent Office: 1,281 Days
• Field of Search: 313500-512, 313/498, 359/619
• US Class Current: 313/504
• CPC Class Codes: G02B 3/0031 Replication or moulding, e.g. hot embossing, UV-casting, injection moulding
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H10K 50/858 comprising refractive means, e.g. lenses
• CPC Class Codes: H10K 59/879 comprising refractive means, e.g. lenses

Abstract

A microlens array for a light emitting device is disclosed. The light emitting device includes a plurality of OLEDs, each OLED having a minimum planar dimension. The array includes a plurality of microlenses, each of which has a minimum planar dimension and a maximum planar dimension. The minimum planar dimensions of the microlenses are larger than the maximum wavelength of visible light emitted from the OLEDs. The maximum planar dimensions of the microlenses are smaller than the smallest minimum planar dimension of any of the OLEDs.

Claims

1. A light emitting device comprising:

at least one OLED having a minimum planar dimension and comprising;

a first electrode;

a second electrode; and

an organic layer disposed between said first electrode and said second electrode; and

a substrate disposed on a surface of said second electrode, said substrate having a plurality of microlenses disposed on a surface thereof, each of said microlenses having a minimum planar dimension and a maximum planar dimension;

wherein said maximum planar dimensions of said microlenses are smaller than the minimum planar dimension of said at least one OLED; and

wherein said organic layer emits light upon application of a voltage between the first and second electrodes, said light having a wavelength that is smaller than the smallest minimum planar dimension of the microlenses.

2. The device of claim 1, wherein said organic layer comprises an electron transporting layer and electroluminescent layer.

3. The device of claim 1, wherein said organic layer comprises a hole transporting layer.

4. The device of claim 1, wherein each of said microlenses has a generally rectangular planar base.

5. The device of claim 1, wherein said maximum planar dimensions of said microlenses are at least an order of magnitude smaller than the minimum planar dimension of the OLED.

6. The device of claim 1, wherein said minimum planar dimensions of said microlenses are at least an order of magnitude larger than said wavelength of said emitted light.

7. The device of claim 1, wherein said microlenses are generally mesa-shaped.

8. The device of claim 1, wherein the maximum planar dimension of each of said microlenses ranges from about 2 micrometers to about 8 micrometers.

9. The device of claim 1, wherein the maximum planar dimension of each of said microlenses ranges from about 4 micrometers to about 6 micrometers.

10. The device of claim 1, wherein the maximum planar dimension of each of said microlenses is about 5 micrometers.

11. A method for the preparation of a light emitting device, said method comprising:

attaching a microlens array to a surface of a light emitting device that comprises a plurality of OLEDs, each of said OLEDs having a minimum planar dimension and emitting light having a respective wavelength;

wherein said microlens array comprises a plurality of generally mesa-shaped microlenses, each of said microlenses having a maximum planar dimension that is larger than a maximum wavelength of light emitted from said OLEDs and smaller than the minimum planar dimension of said OLEDs.

12. The method of claim 11, wherein said microlens array is a polymer laminate.

13. The method of claim 12, wherein said polymer laminate is a polymer selected from polymethylmethacrylates, polyvinylcarbazoles, polybutadienes, polyethylenes and polyesters.

14. The method of claim 11, wherein said microlens array is attached to said surface by physical or chemical bonding.

15. The method of claim 11, wherein said attaching of said microlens array is performed by forming said array on said surface of said substrate.

16. A method for the preparation of a light emitting device, said device comprising a plurality of OLEDs, said OLEDs having a minimum planar dimension;

the method comprising;

providing a substrate, said substrate having a microlens array disposed on a first surface thereof;

depositing a first electrode on a second surface of said substrate;

depositing an organic layer on a surface of said first electrode; and

depositing a second electrode on a surface of said organic layer;

wherein said microlens array comprises a plurality of generally mesa-shaped microlenses, each of said microlenses having a maximum planar dimension that is larger than a maximum wavelength of light emitted from said OLEDs and smaller than the minimum planar dimension of said OLEDs.