Display device with visually-distinguishable watermark area and non-watermark area
The present invention is directed to display devices comprising a watermark area and a non-watermark area. The display cells in the watermark area have widths of the partition walls, heights of the partition walls, top opening shapes or display cell sizes which are different from those of the display cells in the non-watermark area. The watermark aims to protect against counterfeiting or to be used for decoration purposes. The watermark is visible at certain viewing angles and/or under certain lighting conditions and it does not interfere with displaying of the regular images.
1. A display device comprising a layer of display cells filled with a display fluid, the display device further comprising partition walls for separating the display cells, and wherein the display device has a watermark area and a non-watermark area, and each of the display cells in the watermark area has a first size, from each of the display cells in the non-watermark area has a second size, and the first size differs from the second size, the display having a viewing surface and a colored layer on the opposed side of the layer of display cells from the viewing surface.
2. The display device of claim 1 , which is an electrophoretic display.
3. The display device of claim 1 , which is a liquid crystal display.
4. A display device comprising display cells separated by partition walls, the display device having a first watermark area, a second watermark area and a non-watermark area, and wherein for at least one parameter selected from partition wall height, partition wall width and the shape of each display cell, the parameter has a first value in the non-watermark area, a second value in the first watermark area and a third value in the second watermark area, and the first, second and third values are all different from each other, the display having a viewing surface and a colored layer on the opposed side of the layer of display cells from the viewing surface.
5. The display device of claim 4 , which is an electrophoretic display.
6. The display device of claim 4 , which is a liquid crystal display.
7. A display device comprising display cells separated by partition walls, the display device having a watermark area and a non-watermark area, and wherein for at least one parameter selected from partition wall height, partition wall width and the shape of each display cell, the parameter has a first value in the non-watermark area, a second value in the watermark area, and the first and second values are different from each other, the display having a viewing surface and a colored layer on the opposed side of the layer of display cells from the viewing surface.
8. The display device of claim 7 , wherein the at least one parameter comprises the partition wall height.
9. The display device of claim 7 , wherein the at least one parameter comprises the partition wall width.
10. The display device of claim 7 , wherein the at least one parameter comprises the shape of the display cells.
11. The display device of claim 7 , wherein the colored layer is a sealing layer.
12. The display device of claim 7 , wherein the colored layer is an adhesive layer.
13. The display device of claim 7 , wherein the colored layer is an electrode layer.
14. The display device of claim 7 wherein said opposed side is provided with a sealing layer which seals the display cells, an adhesive layer on the opposed side of the sealing layer from the display cells, and an electrode layer on the opposed side of the adhesive layer from the display cells, and the colored layer is formed in one of the sealing, adhesive and electrode layers.
15. The display device of claim 7 , which is an electrophoretic display.
16. The display device of claim 7 , which is a liquid crystal display.