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Color display device

  • US 9,759,981 B2
  • Filed: 01/30/2017
  • Issued: 09/12/2017
  • Est. Priority Date: 03/18/2014
  • Status: Active Grant
First Claim
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1. A method for displaying colors, the method comprising:

  • providing a layer of a display fluid, the layer having a viewing surface, the display fluid comprising first electrophoretic particles bearing a charge of one polarity, second electrophoretic particles bearing a charge of the opposite polarity, one or the first and second particles being white and the other black, and charged third particles bearing a charge of the same polarity as the first particles, the third particles having photonic crystal characteristics in as much as the wavelength of light reflected from a grouping of the third particles varies with the distance between the particles, the first, second and third particles all being dispersed in a solvent or solvent mixture, the method comprising;

    (i) applying a first electric field having a high magnitude and a polarity driving the first particles towards the viewing surface, thereby causing the color of the first particles to be displayed at the viewing surface;

    (ii) applying a second electric field having a high magnitude and a polarity driving the second particles towards the viewing surface, thereby causing the color of the second particles to be displayed at the viewing surface;

    (iii) when the color of the second particles is displayed at the viewing surface, applying a third electric field having the same polarity as, but a lower magnitude than, the first electric field, thereby causing the color of the dispersed third particles to be displayed at the viewing surface; and

    (iv)when the color of the dispersed third particles is displayed at the viewing surface, applying a fourth electric field having the same polarity as the first and third electric fields, and a magnitude intermediate the magnitudes of the first and third electric fields, thereby causing to be displayed at the viewing surface a fourth color which is different from all of black, white and the color of the dispersed third particles.

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