# US 7,746,540 B2 · Electrowetting display devices and fabrication methods thereof

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- Number: US 7,746,540 B2
- Document ID: US7746540B2
- Status: Granted
- Kind: B2
- Application number: 12/240,622
- Filed: 2008-09-29
- Published: 2009-07-02
- Granted: 2010-06-29
- Earliest claimed: 2007-12-28
- Assignees: Industrial Technology Research Institute
- Inventors: Kuo-Lung Lo; Chih-Chun Hsiao
- Web page: https://patentgrep.com/patent/US7746540B2

## CPC

- G02B 26/005: {based on electrowetting}
- Y10T 29/49002: Electrical device making
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Electrowetting display devices and fabrication methods thereof are presented. The electrowetting display device includes a first substrate and a second substrate with a polar fluid layer and a non-polar fluid layer insolvable to each other and interposed between the first and second substrates. A first transparent electrode is disposed on the first substrate. A second electrode is disposed on the second substrate. A dielectric layer is disposed on the second electrode. A hydrophilic partition wall structure is directly disposed on the dielectric layer defining a plurality of pixel regions. A layer of low surface energy material is disposed on the dielectric layer within each of the pixel region.

## Claims

### Claim 1

An electrowetting display device, comprising:
a first substrate and a second substrate opposing to each other with a polar solution layer and a non-polar solution layer interposed therebetween;
a first transparent electrode disposed on the first substrate;
a second electrode disposed on the second substrate;
a dielectric layer disposed on the second electrode;
a bank structure with a hydrophilic surface directly disposed on the dielectric layer, wherein a plurality of regions are defined by the bank structure; and
a layer of low-surface-energy material disposed on the dielectric layer within the plurality of regions.

### Claim 2 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the bank structure comprises two flank extension portions contacting the layer of low-surface-energy material.

### Claim 3 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the bank structure is an array of continuous bank structures with at least one portion directly disposed on the dielectric layer.

### Claim 4 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the bank structure is made of a positive photoresist, a negative photoresist, a photoset resin or a thermoset resin.

### Claim 5 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the bank structure is a black matrix bank structure capable of absorbing visible lights.

### Claim 6 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the first substrate or the second substrate is made of glass, polymer or metal.

### Claim 7 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the first transparent electrode and the second transparent electrode are patterned structures comprising a rectangular, square, triangular, circular, trapezoid, or elliptic shape.

### Claim 8 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the first transparent electrode and the second transparent electrode are made of metal or oxide.

### Claim 9 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the layer of low-surface-energy material comprises fluoride-containing or chloride-containing hydrophobic polymer materials, or fluoride-containing or chloride-containing self-assembly monolayer films.

### Claim 10 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the thickness of the layer of low-surface-energy material is approximately in a range between 0.1 nm and 1 μm, and wherein the surface energy of the layer of low-surface-energy material is approximately 25 dyne/cm.

### Claim 11 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the polar solution layer is made of water, sodium chloride solution, or potassium chloride solution.

### Claim 12 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the non-polar solution layer is made of silicon oil, decane, dodecane, tetradecane, or any combinations thereof.

### Claim 13 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the non-polar solution layer comprises a color dye or a color pigment.

### Claim 14 (depends on 1)

The electrowetting display device as claimed in claim 1, wherein the dielectric layer is made of silicon dioxide (SiO2), silicon nitride (SiNx), tantalum oxide (Ta2O3), lead zirconate titanate (PZT), barium strontium titanate (BST), barium titanate (BTO), parylene, or polyvinylidene difluoride (PVDF).

### Claim 15

An electrowetting display device, comprising:
a first substrate and a second substrate opposing to each other with a transparent polar solution layer and an opaque non-polar solution layer interposed therebetween;
a first transparent electrode disposed on the first substrate;
a second electrode disposed on the second substrate;
a dielectric layer disposed on the second electrode;
a bank structure with a hydrophilic surface directly disposed on the dielectric layer, wherein a plurality of pixel regions are defined by the bank structure; and
a layer of low-surface-energy material disposed on the dielectric layer within the plurality of pixel regions.