Electrophoretic display aparatus and method of driving the same

1. An electrophoretic display apparatus comprising:

a first substrate including a plurality of pixels, each including at least two sub-pixels which display colors different from each other;

a second substrate which faces the first substrate, the second substrate including a reference electrode which corresponds to a boundary between adjacent sub-pixels in each pixel;

an electrophoretic material between the first substrate and the second substrate; and

a barrier wall between the first substrate and the second substrate,

wherein the barrier wall defines pixel areas including the pixels, and

wherein the barrier wall is not between the adjacent sub-pixels.

2. The electrophoretic display apparatus of claim 1 , wherein the reference electrode corresponds to a space between two adjacent sub-pixels in each pixel.

3. The electrophoretic display apparatus of claim 2 , wherein within each of the sub-pixels:

the first substrate further includes:

a reflection layer which reflects a first light incident through the second substrate;

a color layer on the reflection layer, wherein the color layer converts the first light into a second light having a predetermined color; and

a sub-pixel electrode on the color layer, wherein the sub-pixel electrode forms an electric field in cooperation with the reference electrode of the second substrate, and the electric field moves the electrophoretic material.

4. The electrophoretic display apparatus of claim 3 , wherein

each of the pixels comprises four sub-pixels, and

the four sub-pixels comprise a red, green, blue, and white color layer, respectively.

5. The electrophoretic display apparatus of claim 4 , wherein the electrophoretic material comprises:

a dielectric solvent, and

electrophoretic particles in the dielectric solvent, wherein the electrophoretic particles have a black color.

6. The electrophoretic display apparatus of claim 4 , wherein the four sub-pixels are arranged in an array of two rows by two columns in each pixel.

7. The electrophoretic display apparatus of claim 6 , wherein the reference electrode overlaps a boundary between the four sub-pixels, and has a cross shape in each pixel, in a plan view.

8. The electrophoretic display apparatus of claim 1 , wherein the second substrate further includes a dummy reference electrode which faces an upper surface of the barrier wall.

9. The electrophoretic display apparatus of claim 8 , wherein the second substrate further includes a light blocking layer which overlaps an area including the barrier wall and the reference electrode.

10. A method of driving an electrophoretic display apparatus, the method comprising:

applying a reset voltage to sub-pixels of a pixel of the electrophoretic display apparatus during a reset frame; and

applying an image data voltage to the sub-pixels of the pixel during an image frame;

wherein the electrophoretic display apparatus comprises:

a first substrate including a plurality of pixels, each including at least two sub-pixels which display colors different from each other,

a second substrate which faces the first substrate and includes a reference electrode which corresponds to a boundary between adjacent sub-pixels in each pixel,

an electrophoretic material between the first substrate and the second substrate, and

a barrier wall between the first substrate and the second substrate,

wherein the barrier wall defines pixel areas including the pixels, and

wherein the barrier wall is not between the adjacent sub-pixels.

11. The method of claim 10 , wherein

the reference electrode is applied with a reference voltage, the electrophoretic material comprises electrophoretic particles electrified with a first polarity, and the sub-pixels are applied with the reset voltage having a second polarity opposite to the first polarity with respect to the reference voltage, during the reset frame.

12. The method of claim 11 , wherein the electrophoretic particles have a black color and are held on the reference electrode, during the reset frame.

13. The method of claim 12 , wherein each of the pixels comprises four sub-pixels which respectively display red, green, blue, and white colors, respectively, and the four sub-pixels display an image having a white gray scale, during the reset frame.

14. The method of claim 13 , wherein the electrophoretic particles move to a sub-pixel which displays an image having a black gray scale among the four sub-pixels, during the image frame.

15. The method of claim 12 , wherein

the second substrate further includes a dummy reference electrode which faces an upper surface of the barrier wall and receives the reference voltage, and

the dummy reference electrode holds the electrophoretic particles during the reset frame.