# US 11,029,576 B2 · Method for driving two layer variable transmission display

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- Number: US 11,029,576 B2
- Document ID: US11029576B2
- Status: Granted
- Kind: B2
- Application number: 16/662,533
- Filed: 2019-10-24
- Published: 2020-02-20
- Granted: 2021-06-08
- Earliest claimed: 2010-05-21
- Assignees: E Ink Corporation
- Applicants: E Ink Corporation
- Inventors: Stephen J. Telfer; Richard J. Paolini, Jr.; Sunil Krishna Sainis; Randal M. Hill; Isaac W. Moran; Lee Yezek; Alain Bouchard; William Vetterling; George G. Harris; Hywel Morgan; Luke Slominski; Jay William Anseth; Jennifer M. Morrison; Craig A. Herb
- Web page: https://patentgrep.com/patent/US11029576B2

## CPC

- G02F 1/16757: Microcapsules
- G02F 1/167: by electrophoresis
- G02F 1/1347: Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
- G02F 1/1681: having two or more microcells partitioned by walls, e.g. of microcup type
- G02F 2001/1678: {characterised by the composition or particle type}
- G02F 2201/16: series; tandem
- G02F 2203/30: Gray scale
- G02F 2203/34: Colour display without the use of colour mosaic filters
- 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

## Abstract

An electro-optic display comprising at least two separate layers of electro-optic material, with one of these layers being capable of displaying at least one optical state which cannot be displayed by the other layer. The display is driven by a single set of electrodes between which both layers are sandwiched, the two layers being controllable at least partially independently of one another. Another form of the invention uses three different types of particles within a single electrophoretic layer, with the three types of particles being arranged to shutter independently of one another.

## Claims

### Claim 1

A method for driving a variable transmission display comprising a first layer and a second layer of microcavity electro-optic material, wherein the display comprises a first light-transmissive electrode disposed on one side of the first and second layers, and a second light-transmissive electrode disposed on the opposed side of the first and second layers from the first electrode, there being no electrode between the first and second layers, wherein the first layer of microcavity electro-optic material comprises a fluid but is essentially free from pigment particles, the method comprising:
providing a first voltage between the first electrode and the second electrode, thereby creating a substantially opaque state in which charged pigment particles in the second layer of microcavity electro-optic material are dispersed within the microcavity; and
providing a second voltage between the first electrode and the second electrode, thereby creating a light-transmissive state in which charged pigment particles in the second layer of microcavity electro-optic material are concentrated within the microcavity.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the microcavities in the first layer and the microcavities in the second layer are different sizes.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the fluids in the first and second layers differ in at least one of viscosity and electrical conductivity.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the substantially opaque state and the light-transmissive state are bistable.