# US 10,504,457 B2 · Method for driving a passive matrix for an electrophoretic display

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- Number: US 10,504,457 B2
- Document ID: US10504457B2
- Status: Granted
- Kind: B2
- Application number: 15/383,240
- Filed: 2016-12-19
- Published: 2017-04-06
- Granted: 2019-12-10
- Earliest claimed: 2013-03-29
- Assignees: E Ink California, LLC
- Applicants: E Ink California, LLC
- Inventors: Ming Wang; Craig Lin; Hui Du; HongMei Zang; Xiaojia Zhang
- Web page: https://patentgrep.com/patent/US10504457B2

## CPC

- G02F 1/1685: Operation of cells; Circuit arrangements affecting the entire cell
- G02F 1/167: by electrophoresis
- G09G 3/2003: {Display of colours (specific for liquid crystal displays G09G3/3607)}
- G09G 3/344: {based on particles moving in a fluid or in a gas, e.g. electrophoretic devices (electrophoretic devices per se G02F1/167)}
- G02F 2001/1678: {characterised by the composition or particle type}
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)

## Abstract

The present invention is directed to methods of passively driving an electrophoretic display. The electrophoretic fluid comprises three types of particles wherein two types particles are charged pigment particles having opposite charge polarities and contrasting colors. The third type of particle is larger in diameter than the first and second types of particles, and is less charged than the first and second types of particles, i.e., the third particle type is substantially uncharged. The electrophoretic medium is driven with two sets of electrodes, each set comprising a number of addressable electrodes.

## Claims

### Claim 1

A method for driving a passive matrix electrophoretic display between colored states, the passive-matrix electrophoretic display including a first set of electrodes on a viewing side of an electrophoretic medium and a second set of electrodes on a non-viewing side of the electrophoretic medium, wherein the electrophoretic medium includes first, second, and third types of particles, the first type of particles being oppositely-charged and differently-colored than the second type of particles, and the third type of particles being less charged and larger in diameter than the first and second types of particles, the method comprising:
providing a first voltage (V1) to a first electrode belonging to the first set of electrodes; and
providing a second voltage (V2) to a second electrode belonging to the second set of electrodes, wherein 2|V1|=|V2|, and
wherein the passive matrix electrophoretic display does not switch between colored states when only the first voltage (V1) is provided.

### Claim 2 (depends on 1)

The method of claim 1, wherein the first set of electrodes are row electrodes and the second set of electrodes are column electrodes.

### Claim 3 (depends on 1)

The method of claim 1, wherein the first type of particles have a charge density at least twice as large as that of the second type of particles.

### Claim 4 (depends on 1)

The method of claim 1, wherein the first and second types of particles are black and white, respectively.

### Claim 5 (depends on 4)

The method of claim 4, wherein the white particles are negatively charged and the black particles are positively charged, or vice versa.

### Claim 6 (depends on 4)

The method of claim 4, wherein the volume of the black particles is about 3% to about 30% of the volume of the white particles.

### Claim 7 (depends on 4)

The method of claim 4, wherein the third type of particles is white or black.

### Claim 8 (depends on 1)

The method of claim 1, wherein the third type of particles is about 2 to about 50 times the size of the first and second types of particles.

### Claim 9 (depends on 1)

The method of claim 1, wherein the concentration of the third type of particles is less than 25% by volume in the electrophoretic medium.

### Claim 10 (depends on 1)

The method of claim 1, wherein the zeta potential of the first particle is in the range of +120 to +180 mV and the zeta potential of the second particle is in the range of −30 to −60 mV.

### Claim 11 (depends on 1)

The method of claim 1, wherein the zeta potential of the first particle is in the range of +80 to +160 mV and the zeta potential of the second particle is in the range of −20 to −60 mV.

### Claim 12 (depends on 1)

The method of claim 1, further comprising providing the first voltage (V1) to a third electrode belonging to the first set of electrodes.

### Claim 13 (depends on 12)

The method of claim 12, further comprising providing the second voltage (V2) to a fourth electrode belonging to the second set of electrodes.

### Claim 14 (depends on 1)

The method of claim 1, wherein the passive matrix electrophoretic display does not switch between colored states when only the second voltage (V2) is provided.

### Claim 15 (depends on 1)

The method of claim 1, wherein |V1| is approximately 5 Volts, and |V2| is approximately 10 Volts.