US 9,812,073 B2
Color display device
Craig Lin, Oakland, CA (US); and Ming-Jen Chang, New Taipei (TW)
Assigned to E INK CALIFORNIA, LLC, Fremont, CA (US)
Filed by E INK CALIFORNIA, LLC, Fremont, CA (US)
Filed on Nov. 12, 2015, as Appl. No. 14/939,666.
Claims priority of provisional application 62/080,845, filed on Nov. 17, 2014.
Prior Publication US 2016/0140909 A1, May 19, 2016
Int. Cl. G09G 3/34 (2006.01); G09G 3/20 (2006.01)
CPC G09G 3/344 (2013.01) [G09G 3/2003 (2013.01); G09G 2300/0452 (2013.01); G09G 2300/0473 (2013.01); G09G 2310/06 (2013.01); G09G 2310/068 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A driving method for driving an electrophoretic display comprising a first surface on a viewing side, a second surface on a non-viewing side, and an electrophoretic fluid which fluid is sandwiched between a common electrode and a layer of pixel electrodes and comprises a first type of particles, a second type of particles, a third type of particles, and a fourth type of particles, all of which are dispersed in a solvent or solvent mixture, wherein
(a) the four types of pigment particles have optical characteristics differing from one another;
(b) the first type of particles carry high positive charge and the second type of particles carry high negative charge; and
(c) the third type of particles carry low positive charge and the fourth type of particles carry low negative charge,
the method comprises the steps of:
(i) applying a first driving voltage to a pixel in the electrophoretic display for a first period of time to drive the pixel towards the color state of the first or second type of particles at the viewing side; and
(ii) applying a second driving voltage to the pixel for a second period of time, wherein the second driving voltage has a polarity opposite to that of the first driving voltage and an amplitude lower than that of the first driving voltage, to drive the pixel from the color state of the first type of particles towards the color state of the fourth type of particles, or from the color state of the second type of particle towards the color state of the third type of particles, at the viewing side.