Light strips for lighting and backlighting applications

• US 20060034065A1
• Filed: 08/10/2005
• Published: 02/16/2006
• Est. Priority Date: 08/10/2004
• Status: Active Grant

• Current Assignee: Dongbuanam Semiconductor, Inc. (DB HiTek Co., Ltd.), Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Innovalight, Inc. (Corteva, Inc.)
• Inventors: Thurk, Paul
• Granted Patent: US 7,750,352 B2
• Time in Patent Office: Days
• US Class Current: 362/84
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: F21W 2111/02 for roads, paths or the like
• CPC Class Codes: G09F 13/22 electroluminescent electroluminescent light sources per se H05B33/00
• CPC Class Codes: H10K 50/115 comprising active inorganic nanostructures, e.g. luminescent quantum dots
• CPC Class Codes: H10K 50/182 OLED comprising a fiber structure
• CPC Class Codes: H10K 59/30 Devices specially adapted for multicolour light emission
• CPC Class Codes: Y10S 977/773 Nanoparticle, i.e. structure having three dimensions of 100 nm or less

Abstract

Light strips for emergency lighting, path lighting, accent lighting and device lighting are provided. Devices incorporating and lighted by the light strips are also provided. The light strips include a light emitting layer made from a plurality of semiconductor nanoparticles disposed between and in electrical communication with an anode and a cathode. The semiconductor nanoparticles may be made from Group IV semiconductors, such as silicon. Devices that may be lit with the light strips include displays and keypad, such as those found in cellular phones and personal digital assistants.

Claims

1. An electronic device with a lighted keypad, the device comprising a keypad having at least one key, the at least one key incorporating a light strip comprising:

(a) a first substantially transparent electrode layer;

(b) a second electrode layer; and

(c) a plurality of electroluminescent semiconductor nanoparticles disposed between the first and second electrode layers.

2. The device of claim 1 wherein the electronic device is a cellular phone.

3. The device of claim 1 wherein the electronic device is a personal digital assistant.

4. The device of claim 1 wherein the electronic device is a watch.

5. The device of claim 1 further comprising a push-type switch disposed below the at least one key.

6. The device of claim 1 further comprising a display lit by the light strip.

7. The device of claim 6 wherein the display is illuminated with light of higher intensity than the keypad.

8. The device of claim 6 wherein the display is illuminated with light of a different color than the keypad.

9. A light strip comprising:

(a) a first substantially transparent electrode layer;

(b) a second electrode layer; and

(c) a light emitting layer comprising a plurality of electroluminescent semiconductor nanoparticles disposed between the first and second electrodes;

wherein at least one of the density of the nanoparticles or the size distribution of nanoparticles is non-uniform along the length of the light emitting layer.

10. The light strip of claim 9 wherein the density of nanoparticles is non-uniform along the length of the light emitting layer.

11. The light strip of claim 9 wherein the light emitting layer comprises a density gradient of nanoparticles along it length.

12. The light strip of claim 9 wherein the light emitting layer comprises nanoparticle density domains along its length.

13. The light strip of claim 12 wherein the nanoparticle density domains are separated such that a defect in one domain does not affect the remaining domains.

14. The light strip of claim 9 wherein the size distribution of nanoparticles is non-uniform along the length of the light emitting layer.

15. The light strip of claim 14 wherein the light emitting layer comprises a size gradient of nanoparticles along it length.

16. The light strip of claim 14 wherein the light emitting layer comprises nanoparticle size domains along its length.

17. A lighted electronic device comprising:

(a) the light strip of claim 9;

(b) a display lit by the light strip; and

(c) a keypad lit by the light strip.

18. The lighted electronic device of claim 17 wherein the device is selected from the group consisting of cellular phones, personal digital assistants and personal computers.

19. An egress illuminated by the light strip of claim 9.

20. The egress of claim 19 comprising a doorway.

21. The egress of claim 19 comprising an emergency egress in a building or on a vehicle.

22. A shelf illuminated by the light strip of claim 9.