Electrophoretic display device and method of fabrication thereof
Disclosed is an electrophoretic display (EPD) device and fabrication method thereof that has a simplified fabrication process and reduced fabrication costs. In the EPD device, a partition wall is formed directly on a first substrate having a pixel electrode and extended up a lateral surface of the partition wall to prevent dead areas in the pixel region, provide increased aperture ratio, and enhanced image quality.
1. An electrophoretic display device, comprising:
a first substrate and a second substrate having a plurality of pixels, wherein the first substrate includes a display region and a non-display region outside the display region;
a switching device on the first substrate, wherein the switching device includes a gate electrode, a source electrode and a drain electrode;
an insulating layer on the first substrate;
a passivation layer on the entire first substrate including the source electrode and the drain electrode;
partition walls formed in direct contact with the passivation layer between each of the pixels of the first substrate, wherein the partition walls are formed along a boundary region of the pixels arranged on the first substrate;
a pixel electrode on the passivation layer in the display region of the first substrate and on lateral side walls of the partition walls, wherein the pixel electrode directly contacts the drain electrode via a contact hole in the insulating layer;
an electrophoretic layer in an area defined by the partition walls and pixel electrode, wherein the electrophoretic layer is directly on the pixel electrode, and
wherein the electrophoretic layer includes a dispersive medium having charged particles;
a interlayer on the electrophoretic layer;
a common electrode on the second substrate, wherein the common electrode and second substrate are attached to the first substrate,
wherein the pixel electrode is extended from an upper surface of the passivation to the lateral side wall of the partition wall to substantially cover the lateral side wall of the partition wall.
2. The electrophoretic device of claim 1 , wherein the passivation layer and the partition wall are formed of a different material.
3. The electrophoretic device of claim 1 , wherein the passivation layer and the partition wall are formed of a same material.
4. The electrophoretic device of claim 1 , wherein the passivation layer and the partition wall are formed as a single body.
5. The electrophoretic device of claim 1 , wherein the pixel electrode includes a first pixel electrode and a second pixel electrode.
6. The electrophoretic device of claim 5 , wherein the first pixel electrode and the second pixel electrode are a single body.
7. The electrophoretic device of claim 5 , wherein the first pixel electrode is formed on the passivation layer and directly connects to the drain electrode of the switching device through the contact hole.
8. The electrophoretic device of claim 7 , wherein the second pixel electrode is formed on the first pixel electrode and side walls of the partition walls.
9. The electrophoretic device of claim 7 , wherein the second pixel electrode is formed only on the side walls of the partition walls.
10. The electrophoretic device of claim 1 , wherein the charged particles include at least one of white particles, black particles and color particles.
11. The electrophoretic device of claim 1 , wherein the dispersive medium includes liquid or air.
12. The electrophoretic device of claim 1 , further comprising a sealing layer formed on the electrophoretic layer and the interlayer.
13. The electrophoretic device of claim 1 , further comprising a sealing layer formed on the partition wall.
14. The electrophoretic device of claim 12 , wherein the first and second substrates are attached via the sealing layer.
15. A method of fabricating an electrophoretic display device, comprising:
providing first and second substrates having a plurality of pixels, wherein the first substrate includes a display region and a non-display region outside the display region;
forming a thin film transistor having a gate electrode, a gate insulation layer, a semiconductor layer, a source electrode, and a drain electrode in a unit pixel of the first substrate;
forming an insulation layer on an entire surface of the first substrate including the thin film transistor;
positioning a mask including a blocking portion, a half-transparent portion, and a transparent portion on the insulation layer, wherein a portion of the insulation layer corresponding to a display region of the first substrate is fully exposed, a portion of the insulation layer corresponding to the drain electrode of the thin film transistor is partially exposed, and a portion of the insulation layer corresponding to a non-display region of the first substrate is not exposed;
forming partition walls, a passivation layer and a contact hole in the passivation layer by etching the fully exposed and partially exposed portions of the insulation layer; and
forming a pixel electrode on the passivation layer and on side walls of the partition walls forming partition walls in direct contact with a passivation layer between each of the pixels of the first substrate, wherein the partition walls are formed along a boundary region of pixels arranged on the first substrate,
wherein the pixel electrode is extended from an upper surface of the passivation to the lateral side wall of the partition wall to substantially cover the lateral side wall of the partition wall.
16. The method of claim 15 , further comprising:
forming an electrophoretic layer by providing an electrophoretic material in the display region of the first substrate between the partition walls;
providing an interlayer on the partition walls;
forming a common electrode on the second substrate; and
attaching the second substrate including the common electrode to the first substrate.
17. The method of claim 15 , wherein the partition walls and passivation layer are formed using separate processes.
18. The method of claim 15 , wherein the partition walls and passivation layer are formed simultaneously.
19. The method of claim 18 , further comprising forming a photo-resist layer on the first substrate and arranging a mask to form the passivation layer and the partition walls.
20. The method of claim 15 , wherein the insulation layer is formed of a photosensitive resin.
21. The method of claim 15 , wherein forming a pixel electrode on the passivation layer and on side walls of the partition walls comprises forming a first pixel electrode on the insulation layer and a second pixel electrode on sides of the partition walls.
22. The method of claim 21 , wherein the first pixel electrode and second pixel electrode are a single body.