Method and apparatus for calibrating a tunable microlens

• US 20030206351A1
• Filed: 05/03/2002
• Published: 11/06/2003
• Est. Priority Date: 06/19/2001
• Status: Active Grant

• Current Assignee: Timofei Nikita Kroupenkine
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Kroupenkine, Timofei Nikita
• Granted Patent: US 6,965,480 B2
• Time in Patent Office: Days
• US Class Current: 359/665
• CPC Class Codes: G02B 2207/115 Electrowetting
• CPC Class Codes: G02B 26/005 based on electrowetting
• CPC Class Codes: G02B 3/12 Fluid-filled or evacuated lenses
• CPC Class Codes: G02B 3/14 of variable focal length
• CPC Class Codes: G02F 2203/18 adaptive optics, e.g. wavefront correction
• CPC Class Codes: G02F 2203/28 focussing or defocussing

Abstract

A tunable microlens uses at least two layers of electrodes and a droplet of conducting liquid. Such a droplet, which forms the optics of the microlens, moves toward an electrode with a higher voltage relative to other electrodes in the microlens. When calibration of the microlens is desired, an equal and constant voltage is passed over the first layer of electrodes and a different, constant voltage is passed over the second layer of electrodes, which may, for example, be disposed in a star-like pattern. A driving force relative to each electrode in the second layer results and is proportional to the length of the circumference of the droplet that intersects with each of the electrodes. This driving force reaches equilbrium, and hence the droplet reaches its nominal centered position relative to the second layer of electrodes, when the length of intersection of the circumference of the droplet with each of the electrodes in the second layer is equal.

Claims

1. A tunable liquid microlens comprising:

a first plurality of electrodes;

a conducting liquid; and

a second plurality of electrodes configured such that application of an equal and constant voltage to said second plurality of electrodes causes said conducting liquid to be positioned in a nominal position relative to the electrodes in either said first plurality or said second plurality of electrodes.

2. The tunable liquid microlens of claim 1 further comprising a transparent conducting substrate of a material that is transparent to at least one wavelength of light.

3. The tunable liquid microlens of claim 2 further comprising a dielectric insulating layer that insulates said plurality of electrodes from said droplet.

4. The tunable liquid microlens of claim 1 wherein a voltage across said conducting liquid is constant.

5. The tunable liquid microlens of claim 1 wherein the sum of the intersection lengths formed by an intersection of the circumference of a droplet of said conducting liquid with second plurality of electrodes changes as the distance from the center of said second plurality of electrodes increases.

6. A method for use in calibrating a liquid microlens with a droplet of conducting liquid, said method comprising:

passing a first constant voltage over a first plurality of electrodes; and

passing at least a second constant voltage over a second plurality of electrodes in order to cause said droplet to move to a nominal position.

7. The method of claim 6 wherein the voltage passed over each electrode in said second plurality of electrodes is the same.

8. The method of claim 6 wherein the voltage passed over each electrode in said second plurality of electrodes is not the same.

9. The method of 6 wherein said second constant voltage is greater than a voltage on said droplet of conducting liquid.

10. A tunable liquid microlens comprising:

a first plurality of electrodes;

a droplet of conducting liquid disposed on a hydrophobic surface;

a second plurality of electrodes arranged in a pattern and disposed between said first layer of electrodes and said droplet; and

an insulating layer separating said droplet of conducting liquid from said first plurality of electrodes and said second plurality of electrodes;

wherein the sum of the intersection lengths formed by the intersection of the circumference of the droplet of liquid and the pattern of the second plurality of electrodes changes as the distance from the center of said pattern of said second plurality of electrodes increases.

11. The tunable liquid microlens of claim 10 wherein said second plurality of electrodes is arranged in a star-like pattern.