Highlight color display architecture using enhanced dark state
View Patent ↗The present invention is directed to a highlight color display. One of the key features of the invention is the dark color of the display fluid filled in the microcups, which allows the dark state to appear black. There is no alignment required between the pixel electrodes and the microcups. In practice, a standard active matrix array may be used to drive the display device.
1. A color display device comprising
A) a plurality of microcups, wherein
a) said microcups are separated by transparent partition walls,
b) said microcups are filled with a display fluid comprising white charged pigment particles dispersed in a solvent of a dark color, and the solvent is of the same color in all the microcups, and
c) said microcups are sandwiched between a first layer and a second layer wherein said first layer comprises a common electrode and is on a viewing side and said second layer comprises a plurality of pixel electrodes, and
B) an adhesive layer on the opposite side of the viewing side and the adhesive layer has a black color or a color complementary to the dark color of the solvent,
whereby each area corresponding to a pixel electrode displays a white color state when the white charged pigment particles are driven to be near or at the common electrode, displays a black color state when the white charged pigment particles are driven to be near or at the pixel electrode to cover the pixel electrode, wherein the black color state is the dark color of the solvent enhanced by the color of the adhesive layer seen through the transparent partition walls, and displays a medium color state of the solvent when the white charged pigment particles are driven to an area between the common and pixel electrodes.
2. The color display device of claim 1 , further comprising an adhesive layer of a dark color or a color complementary to the color of the solvent, and the adhesive layer is at the opposite side of the viewing side of the display device.
3. The color display device of claim 1 , wherein the top surface of the partition walls is of a dark color or a color complementary to the color of the solvent.
4. The color display device of claim 1 , wherein the partition walls are of a black or dark color.
5. The color display device of claim 1 , wherein no more than 10% of the light is reflected at the peak transmission of the dark color state.
6. The color display device of claim 5 , wherein no more than 3% of the light is reflected at the peak transmission of the dark color state.
7. The color display device of claim 1 , wherein the medium color of the solvent has a reflectance at least ten times the reflectance of the dark color state.
8. The color display device of claim 1 , wherein said microcups and said pixel electrodes are aligned.
9. The color display device of claim 8 , wherein each microcup represents a pixel.
10. The color display device of claim 1 , wherein said microcups and said pixel electrodes are un-aligned.
11. The color display device of claim 1 , wherein said pixel electrodes are active matrix driving electrodes.
12. The color display device of claim 1 , wherein the dark color of the solvent is dark red, dark green or dark blue.