Color Tuneable electroluminescent devices

• US 7,839,467 B2
• Filed: 10/16/2009
• Issued: 11/23/2010
• Est. Priority Date: 08/17/2007
• Status: Active Grant

• Current Assignee: Kirsteen Mgmt Group LLC (Intellectual Ventures LLC)
• Original Assignee: Group Iv Semiconductor Inc.
• Inventors: Miner, Carla, Tweddle, Howard, Naor, Stephen, MacElwee, Thomas
• Primary Examiner(s): QI, ZHI QIANG
• Application Number:
  US12/580,343
• Publication Number:
  US 20100033111A1
• Time in Patent Office: 403 Days
• Field of Search: 349/69, 349/61, 349/108
• US Class Current: 349/69
• CPC Class Codes: G02F 1/133602 Direct backlight
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 1/133622 Colour sequential illumination
• CPC Class Codes: G02F 2201/44 Arrangements combining different electro-active layers, e.g. electrochromic, liquid crystal or electroluminescent layers

Abstract

The present invention replaces conventional lighting devices, such as incandescent lamps, fluorescent lamps, and LED lamps, with an integrated electro-luminescent film structure, subdivided into electrically isolated micro-panels. Ideally, the electro-luminescent structure comprises separate red, green and blue micro-panels providing a full range of color adjustment. Alternatively, the electro-luminescent film structure includes stacked groups of layers, in which each group emits a different color and is independently controllable.

Claims

1. An electro-luminescent film structure comprising:

a substrate;

a multi-color light emitting film structure supported by the substrate comprising a plurality of independently-controllable, multi-layer, color-emitting micro-panels including a first micro-panel for emitting light at a first wavelength, and a second micro-panel for emitting light at a second wavelength different from the first wavelength; and

a set of upper and lower contacts for each micro-panel, each set of contacts isolated from each other, for independently applying an electric field to each micro-panel, whereby the first and second wavelengths can be selectively emitted together or separately;

a controller for actuating the sets of upper and lower contacts for generating a uniform color from the first and second wavelengths of the first and second micro-panels, respectively.

2. The electro-luminescent film structure according to claim 1, wherein the light emitting film structure includes a pattern of field oxide regions on the substrate forming wells therebetween;

and

a single multi-layer light emitting film disposed over the field oxide regions and into the wells, whereby the light emitting film disposed in the wells forms the micro-panels.

3. The electro-luminescent film structure according to claim 2, wherein the field oxide regions form an array of wells.

4. The electro-luminescent film structure according to claim 1, wherein the first micro-panel is superposed above the second micro-panel.

5. The electro-luminescent film structure according to claim 1, wherein the first and second wavelengths are combined with or without additional wavelengths to form white light.

6. The electro-luminescent film structure according to claim 1, wherein the first micro-panel comprises:

a first active layer including a concentration of luminescent centers for emitting light at the first wavelength;

a first buffer layer comprising a wide bandgap semiconductor or a dielectric material adjacent the first active layer; and

wherein the first buffer layer has a thickness whereby electrons gains sufficient energy from the electric field when passing through the first buffer layer to excite the luminescent centers in the first active layer via impact ionization or impact excitation at a sufficient excitation energy to emit light at the first wavelength.

7. The electro-luminescent film structure according to claim 6, wherein the first micro-panel further comprises:

a plurality of additional first active layers; and

a plurality of additional first buffer layers forming a first stack with first active layers alternating with first buffer layers between the set of electrodes.

8. The electro-luminescent film structure according to claim 7, wherein the second micro-panel further comprises:

a plurality of second active layers, each including a concentration of luminescent centers for emitting light at the second wavelength; and

a plurality of second buffer layers comprising a wide bandgap semiconductor or dielectric material interleaved with the plurality of second active layers;

wherein each of the second buffer layers has a thickness, whereby electrons gains sufficient energy from the electric field when passing through the second buffer layers to excite the luminescent centers in the second active layers via impact ionization or impact excitation at an excitation energy to emit light at the second wavelength.

9. The electro-luminescent film structure according to claim 1, wherein the light emitting film structure comprises a plurality of first micro-panels, and a plurality of second micro-panels.

10. The electro-luminescent film structure according to claim 9, wherein the plurality of first micro-panels emit red colored light, and the plurality of second micro-panels emit green colored light;

and wherein the light emitting film structure also includes a plurality of third micro-panels for emitting a blue colored light.

11. The electro-luminescent film structure according to claim 10, wherein the plurality of micro-panels form an array, which alternates between red, green and blue colored micro-panels.

12. The electro-luminescent film structure according to claim 10, wherein the luminescent centers in the first, second and third micro-panels comprise rare earth elements or oxides of rare earth elements.

13. The electro-luminescent film structure according to claim 12, wherein each of the rare earth elements is comprised of a lanthanide element.

14. The electro-luminescent film structure according to claim 13, wherein each of the lanthanide elements is selected from the group consisting of cerium, praeseodymium, neodynium, promethium, gadolinium, erbium, thulium, ytterbium, samarium, dysprosium, terbium, europium, holmium, and lutetium.

15. The electro-luminescent film structure according to claim 10, further comprising a color sequencing controller for alternating between emitting the red, green and blue light from the first, second and third groups of micro-panels at a frequency whereby a certain color appears which is a combination in different proportions of red, green and blue light.