Semi-finished display panels

Abstract

This application is directed to electrophoretic displays and semi-finished display panels comprising display cells prepared from the microcup and top-sealing technologies. The semi-finished display panel comprises an array of display cells sandwiched between two temporary substrate layers, between a temporary substrate layer and a conductor layer or between a temporary substrate layer and a permanent substrate layer, wherein said display cells are filled with an electrophoretic fluid and top-sealed with a polymeric sealing layer formed from a top-sealing composition which is being hardened while on top of the electrophoretic fluid.

Description

[0001] This application is a continuation-in-part of U.S. application Ser. No. 10 / 351,460, filed Jan. 24, 2003; which is a continuation-in-part of U.S. application Ser. No. 09 / 518,488, filed Mar. 3, 2000, now U.S. Pat. No. 6,930,818; the contents of both applications are incorporated herein by reference in their entirety.BACKGROUND OF THE INVENTION [0002] a) Field of the Invention [0003] This invention is directed to electrophoretic displays and semi-finished display panels comprising display cells prepared from the microcup and top-sealing technologies. [0004] b) Description of Related Art [0005] The electrophoretic display is a non-emissive device based on the electrophoresis phenomenon of charged pigment particles suspended in a solvent. It was first proposed in 1969. The display usually comprises two plates with electrodes placed opposing each other, separated by using spacers. One of the electrodes is usually transparent. A suspension composed of a colored solvent and charged p...

AI Technical Summary

Benefits of technology

[0024] A color filter layer or a protective overcoat such as an antiglare protective coating comprising a particulate filler may be applied onto the top-sealed microcups or the second conductor layer to further improve the optical or physicomechanical properties of the finished panel.

[0025] These multiple-step processes as disclosed may also be carried out roll-to-roll on a web continuously or semi-continuously. The microcup structure in fact enables a format flexible and efficient roll-to-roll continuous manufacturing. These processes are very cost effective as compared to typical display manufacturing processes.

[0026] One advantage of the electrophoretic display (EPD) of this invention is that the microcup wall is in fact a built-in spacer to keep the top and bottom substrates apart at a fixed distance. The mechanical properties and structural integrity of this type of display is significantly better than any prior art displays including those manufactured by using spacer particles. In addition, displays involving microcups have desirable mechanical properties including reliable display performance when the display is bent, rolled, or under compression pressure from, for example, a touch screen application. The use of the microcup technology also eliminates the need of an edge seal adhesive to predefine the size of the display panel and confine the display fluid inside a predefined area. The display fluid within a conventional display prepared by the edge sealing adhes...

Problems solved by technology

However, in the case of partition-type electrophoretic displays, some difficulties were encountered in the formation of the partitions and the process of enclosing the suspension.

Furthermore, it was also difficult to keep suspensions of different colors separate from each other in the partition-type electrophoretic display.

For example, the electrophoretic display manufactured by the microencapsulation process suffers from sensitivity to environmental changes (in particular sensitivity to moisture and temperature) due to the wall chemistry of the microcapsules.

Secondly, the electrophoretic display based on the microcapsules has poor scratch resistance due to the thin wall and large particle size of the microcapsules.

To improve the handleability of t...

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