Display capable electrowetting light valve

• US 7,872,790 B2
• Filed: 07/08/2005
• Issued: 01/18/2011
• Est. Priority Date: 07/09/2004
• Status: Active Grant

• Current Assignee: University of Cincinnati
• Original Assignee: University of Cincinnati
• Inventors: Heikenfeld, Jason C., Steckl, Andrew J.
• Primary Examiner(s): MARTINEZ, JOSEPH P
• Application Number:
  US11/570,920
• Publication Number:
  US 20080297880A1
• Time in Patent Office: 2,020 Days
• Field of Search: 359/296, 359/253, 359/320, 359/228
• US Class Current: 359/253
• CPC Class Codes: G02B 26/004 based on a displacement or a deformation of a fluid
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements

Abstract

The invention relates to light transmissive, transflective, or reflective flat panel display devices and, more specifically, to light emissive flat panel displays constructed from high performance electrowetting light valve (ELV) devices (10a-g). An array of ELV devices (10a-g) is mounted on or adjacent to a backlight (11), employing a reflector (13) allowing for improved transmission. The backlight (11) may be partially diffusely reflective or translucent as to also allow for creation of a transflective display panel.

Claims

1. A light-emitting device for a display, comprising:

an insulator;

a plurality of electrodes;

an amount of a first liquid separated from at least one of said electrodes by said insulator;

an amount of a second liquid disposed within said first liquid, said second liquid movable relative to said first liquid, and said second liquid having a lower light transmittance than said first liquid;

an illumination source adapted to generate light;

an optical path extending through said second liquid and said insulator, said optical path adapted to transmit light received from said illumination source; and

a voltage source connected to said electrodes, said voltage source adapted to apply an electric field between said electrodes effective to move said second liquid relative to said first liquid to block at least a portion of the light from said illumination source from being transmitted through said optical path.

2. The light-emitting device of claim 1 further comprising:

a reflective layer with an aperture positioned in said optical path, said aperture operative to transmit the light from said illumination source to said optical path, and portions of said reflective layer adjacent to said aperture operative to reflect the light from said illumination source in a direction back toward said illumination source.

3. The light-emitting device of claim 1 further comprising:

an optical layer positioned in said optical path, said optical layer operative to transmit the light from said illumination source to said optical path, and said optical layer operative to reflect external ambient light incident upon said device.

4. The light-emitting device of claim 1 further comprising:

a focusing optical layer positioned in said optical path, said focusing optical layer operative to direct the light from said illumination source around said second liquid when a potential is applied to said electrodes effective to transmit light through said optical path.

5. The light-emitting device of claim 4 further comprising:

a reflective layer positioned in said optical path, said reflective layer operative to reflect external ambient light incident upon said device.

6. The light-emitting device of claim 1 wherein said first liquid is polar, said second liquid is non-polar, and said first and second liquids are non-miscible.

7. The light-emitting device of claim 1 wherein said first liquid is substantially transparent and said second liquid is substantially opaque.

8. The light-emitting device of claim 7 wherein said first liquid is transparent and said second liquid is black or colored.

9. The light-emitting device of claim 1 further comprising:

first and second separators flanking said first and second liquids, the first and second separators being substantially hydrophilic for confining said first and second liquids between said electrodes.

10. A light-emitting device for a display, comprising:

an insulator;

a plurality of electrodes;

an amount of a fluid separated from at least one of said electrodes by said insulator;

an amount of a liquid disposed within said fluid, said liquid movable relative to said fluid, said liquid and said fluid being confined between said electrodes, and said liquid having a greater refractive index than said fluid;

an illumination source;

an optical path extending through said-fluid, said liquid, and said insulator, said optical path adapted to transmit light received from said illumination source; and

a voltage source connected to said electrodes, said voltage source adapted to apply an electric field between said electrodes effective to move said liquid relative to said fluid and thereby cause an optical phase shift that prevents at least a portion of the light from said illumination source from being transmitted through said optical path.

11. The light-emitting device of claim 10 wherein said fluid is a gas.

12. A method of operating a pixel in a flat panel display, comprising:

transmitting light through an optical path in the pixel; and

moving an amount of a liquid relative to the optical path effective to change an intensity of the transmitted light through the optical path.

13. The method of claim 12 wherein moving the amount of the liquid further comprises:

applying a first electric field effective to displace the amount of the liquid relative the optical path to provide a first intensity of the transmitted light through the optical path; and

applying a second electric field effective to displace the amount of the liquid relative to the optical path to provide a second intensity of the transmitted light through the optical path differing from the first percentage.

14. The method of claim 12 wherein moving the amount of the liquid further comprises:

applying an electric field effective to move the amount of the liquid relative the optical path.

15. The method of claim 14 wherein applying the electric field further comprises:

causing an optical phase shift with the amount of the liquid that changes the intensity of the transmitted light.

16. The method of claim 14 wherein applying the electric field further comprises:

displacing the liquid to block at least a portion of the optical path to change the intensity of the transmitted light.

17. A light-emitting device for a display, comprising:

an insulator;

a plurality of electrodes;

an amount of a first liquid separated from at least one of said electrodes by said insulator;

an amount of a second liquid disposed within said first liquid, said first liquid and said second liquid movable relative to each other, and said second liquid having a lower light transmittance than said first liquid;

an illumination source adapted to generate light;

an optical path extending through said second liquid and said insulator, said optical path adapted to transmit light received from said illumination source; and

a voltage source connected to said electrodes, said voltage source adapted to apply an electric field between said electrodes effective to move said first liquid and said second liquid relative to each other to block at least a portion of the light from said illumination source from being transmitted through said optical path.

18. The light-emitting device of claim 17 further comprising:

a reflective layer with an aperture positioned in said optical path, said aperture operative to transmit the light from said illumination source to said optical path, and portions of said reflective layer adjacent to said aperture operative to reflect the light from said illumination source in a direction back toward said illumination source.