Coloured structures

1. An elongate colored structure comprising:

an electrically conductive wire;

a dye layer surrounding at least a portion of the electrically conductive wire, wherein the dye layer absorbs a first wavelength of light corresponding to a first color when the dye layer is in a first state, and further wherein the dye layer has a thickness of less than 50 μm; and

an electrically conductive, light transmissive layer surrounding at least a portion of the dye layer;

wherein the dye layer enters a second state when a voltage is applied between the electrically conductive wire and the light transmissive layer, wherein the dye layer absorbs a second wavelength of light corresponding to a second color when the dye layer is in the second state.

2. The structure as claimed in claim 1 having a diameter of less than 0.5 mm.

3. The structure as claimed in claim 1 having a diameter of less than 0.2 mm.

4. The structure as claimed in claim 1 wherein the light transmissive layer comprises a plastic.

5. The structure as claimed in claim 1 wherein the light transmissive layer comprises indium tin oxide or fluorine doped SnO 2 .

6. The structure as claimed in claim 1 wherein a thickness of the dye layer is less than 20 μm.

7. The structure as claimed in claim 1 wherein a thickness of the dye layer is less than 10 μm.

8. The structure as claimed in claim 1 , wherein the dye layer is configured to absorb a third wavelength of light when a second voltage is applied between the electrically conductive wire and the light transmissive layer, wherein absorption of the third wavelength of light causes the dye layer to have a third color.

9. The structure as claimed in claim 1 wherein the structure is flexible.

10. The structure as claimed in claim 1 wherein the dye layer comprises an oxidation dye or a reduction dye.

11. The structure as claimed in claim 1 wherein the dye layer comprises a viologen.

12. The structure as claimed in claim 1 wherein the dye layer comprises a porous insulating material or a semi-conducting material.

13. A portable device, comprising:

a plurality of structures extending from an exterior surface of the device, and further comprising a driving unit configured to selectively apply voltages to the plurality of structures, wherein each of the plurality of structures comprises

an electrically conductive wire;

a dye layer surrounding at least a portion of the electrically conductive wire; and

an electrically conductive, light transmissive layer surrounding at least a portion of the dye layer;

wherein the dye layer is configured to change its color when a voltage is applied between the electrically conductive wire and the light transmissive layer; and

an analyzing unit in communication with the driving unit and configured to analyze an image, wherein the driving unit is configured to selectively apply the voltages to the plurality of structures such that the image is represented by the plurality of structures.

14. The device as claimed in claim 13 wherein the driving unit comprises a series of row electrodes and a series of column electrodes, wherein each of the plurality of structures is electrically connected to one of the row electrodes and one of the column electrodes such that the voltage is applied across the dye layer.

15. The device as claimed in claim 13 further comprising a memory for storing a predefined mode, wherein the predefined mode includes a predefined voltage to be applied to each of the plurality of structures.

16. The device as claimed in claim 15 further comprising a user input mechanism allowing a user to select the predefined mode such that each of the plurality of structures has a predefined color.

17. The device as claimed in claim 13 wherein the driving unit is configured to vary the voltages applied to the plurality of structures with time.

18. A removable cover for a portable device, the cover comprising:

a plurality of structures extending from an exterior surface of the cover, wherein the plurality of structures are electrically connected to a driving arrangement, wherein each structure comprises

an electrically conductive wire;

a dye layer surrounding at least a portion of the electrically conductive wire; and

an electrically conductive, light transmissive layer surrounding at least a portion of the dye layer;

wherein the dye layer is configured to change its color when a voltage is applied between the electrically conductive wire and the light transmissive layer; and

an analyzing unit in communication with the driving arrangement and configured to analyze an image, wherein the driving arrangement is configured to selectively apply voltages to the plurality of structures such that the image is represented by the plurality of structures.

19. The removable cover as claimed in claim 18 further comprising an electrical bus for connecting the plurality of structures to the driving arrangement.

20. A method for constructing an elongated colored structure, the method comprising:

providing an electrically conductive wire;

surrounding at least a portion of the electrically conductive wire with a dye layer having a thickness less than 50 μm; and

surrounding at least a portion of the dye layer with an electrically conductive, light transmissive layer, wherein the dye layer is configured to absorb a first wavelength of light corresponding to a first color when there is not an electric potential across the dye layer, and further wherein the dye layer is configured to absorb a second wavelength of light corresponding to a second color when a voltage is applied between the electrically conductive wire and the light transmissive layer.

21. An apparatus comprising:

an electrically conductive means for conducting electricity;

a dye layer means surrounding at least a portion of the electrically conductive means, wherein said dye layer means absorbs a first wavelength of light corresponding to a first color when the dye layer is in a first state, and further wherein the dye layer means has a thickness of less than 50 μm; and

an electrically conductive, light transmissive means surrounding at least a portion of the dye layer means, said light transmissive layer for transmitting light;

wherein the dye layer means is configured to enter a second state when a voltage is applied between the electrically conductive means and the light transmissive means, wherein the dye layer means absorbs a second wavelength of light corresponding to a second color when the dye layer means is in the second state.

22. A portable device comprising:

a plurality of structures extending from an exterior surface of the device, further comprising a driving arrangement configured to selectively apply voltages to the plurality of structures, an analyzing unit for analyzing a digital image and an output unit for outputting to the driving arrangement a signal indicating, for each structure, a voltage to be applied to the structure such that the image is represented by the plurality of structures, wherein each of the plurality of structures comprises

an electrically conductive wire;

a dye layer surrounding at least a portion of the electrically conductive wire; and

an electrically conductive, light transmissive layer surrounding at least a portion of the dye layer;

wherein the dye layer is configured to change its color when the voltage is applied between the electrically conductive wire and the light transmissive layer.

23. The structure as claimed in claim 1 , said structure having a diameter of less than 1 mm.