CN-122018142-A - Electrowetting display with gradient electric field

CN122018142ACN 122018142 ACN122018142 ACN 122018142ACN-122018142-A

Abstract

The invention discloses an electrowetting display with a gradient electric field, which comprises an upper substrate assembly, a lower substrate assembly and a pixel layer, wherein the upper substrate assembly and the lower substrate assembly are oppositely arranged, the pixel layer is clamped between the upper substrate assembly and the lower substrate assembly, the pixel layer comprises a plurality of pixel areas which are arrayed, each pixel area is filled with a polar aqueous solution and nonpolar colored ink which are mutually insoluble, the lower substrate assembly comprises a lower substrate, a driving electrode layer, a reflecting layer and a lower hydrophobic insulating layer, the driving electrode layer, the reflecting layer and the lower hydrophobic insulating layer are sequentially laminated on one side of the lower substrate, which faces towards the pixel layer, the driving electrode layer comprises a plurality of pixel electrodes which are in one-to-one correspondence with each pixel area, and the pixel electrodes can generate a gradient electric field, and the electric field strength of the gradient electric field in the pixel areas is increased from the center of a pixel to the edge of the pixel. The electrowetting display can improve the response speed during bright and dark switching of the pixel.

Inventors

LIU FUZHI
LI YAN
ZHUO SHAOZHONG
ZHANG LEI
YANG XILIN

Assignees

信利光电仁寿有限公司

Dates

Publication Date: 20260512
Application Date: 20260319

Claims (10)

1. The electrowetting display with the gradient electric field comprises an upper substrate assembly, a lower substrate assembly and a pixel layer, wherein the upper substrate assembly and the lower substrate assembly are oppositely arranged, the pixel layer is clamped between the upper substrate assembly and the lower substrate assembly, the pixel layer comprises a plurality of pixel areas which are arrayed, each pixel area is filled with a polar aqueous solution and nonpolar colored ink which are mutually insoluble, the lower substrate assembly comprises a lower substrate, a driving electrode layer, a reflecting layer and a lower hydrophobic insulating layer, the driving electrode layer, the reflecting layer and the lower hydrophobic insulating layer are sequentially laminated on one side of the lower substrate towards the pixel layer, and the driving electrode layer comprises a plurality of pixel electrodes which are in one-to-one correspondence with the pixel areas.
2. An electrowetting display according to claim 1, wherein the pixel electrode is of a spiral structure extending helically from inside to outside around a pixel center of the pixel area.
3. An electrowetting display according to claim 1, wherein the pixel electrode comprises a plurality of rectangular electrode blocks, each rectangular electrode block of the same pixel electrode is connected end to end in turn, and the pixel centers surrounding the pixel region are spirally distributed from inside to outside.
4. An electrowetting display according to claim 2 or 3, wherein the widths of the spiral or rectangular electrode blocks are the same throughout the pixel electrode, but the pitch of adjacent spiral or rectangular electrode blocks decreases in gradient from the pixel center to the pixel edge.
5. An electrowetting display according to claim 2 or 3, wherein the pitch of adjacent spiral or rectangular electrode segments is the same throughout the pixel electrode, but the width of the spiral or rectangular electrode segments decreases in gradient from the pixel centre to the pixel edge.
6. An electrowetting display according to claim 2 or 3, wherein the widths of the spiral or rectangular electrode blocks everywhere of the pixel electrodes decrease in a gradient from the pixel center to the pixel edge, and the pitches of adjacent spiral or rectangular electrode blocks decrease in a gradient from the pixel center to the pixel edge.
7. An electrowetting display according to claim 1, wherein a side surface of the lower hydrophobic insulating layer facing the pixel layer is provided with groove groups at positions corresponding to each pixel region, each groove group comprising a plurality of guide grooves, one end of each guide groove of the same pixel region being directed towards the center of the pixel and the other end being directed towards the periphery of the pixel, in a radial distribution.
8. An electrowetting display according to claim 1, wherein the pixel layer comprises pixel walls arranged in a grid to separate individual pixel areas.
9. The electrowetting display of claim 1, wherein the upper substrate assembly comprises an upper substrate and a common electrode layer, the common electrode layer being arranged layer upon layer on a side of the upper substrate facing the pixel layer.
10. The electrowetting display of claim 9, wherein the upper substrate assembly further comprises an upper hydrophobic insulating layer, the upper hydrophobic insulating layer being disposed on a side of the common electrode layer facing the pixel layer.

Description

Electrowetting display with gradient electric field Technical Field The invention relates to an electrowetting display technology, in particular to an electrowetting display with a gradient electric field. Background The electrowetting display technology is a novel reflective display technology based on the electrowetting effect. Electrowetting refers to a physical phenomenon in which the wettability of a solid-liquid interface, i.e., a contact angle, is changed by changing the electric potential acting between a liquid and a solid electrode to affect the interfacial tension of the solid-liquid interface, thereby deforming or displacing a droplet. The electrowetting display technology has the advantages of low power consumption, high reflectivity, high contrast, no viewing angle limitation, quick response and the like, and is considered to be an important development direction of the next-generation electronic paper display technology. The basic structure of the electrowetting display comprises a pixel electrode, a reflecting layer, a hydrophobic insulating layer, colored ink and conductive aqueous solution. The pixel electrode has the working principle that when a driving voltage is not applied to the pixel electrode, the affinity of the hydrophobic insulating layer to the colored ink is larger than the affinity to the conductive aqueous solution, the colored ink can move from the periphery of the pixel to the center of the pixel under the action of self tension, spread and spread on the whole pixel area to enable the pixel area to present ink color, when the driving voltage is applied to the pixel electrode, the surface characteristics of the hydrophobic insulating layer are changed by a driving electric field to enable the hydrophobic insulating layer to become hydrophilic so as to attract the conductive aqueous solution to move close, and the colored ink moves from the center of the pixel to the periphery of the pixel under the action of extrusion of the conductive aqueous solution so as to shrink on the periphery of the pixel, so that the pixel area becomes transparent, and the reflective layer at the bottom is exposed. In theory, the colored ink should be moved in a radial direction from the pixel center to the pixel periphery, or from the pixel periphery to the pixel center, whether it is contracted or spread. However, the pixel electrode of the conventional electrowetting display adopts a uniform electric field design, and lacks space guidance to the shrinkage direction of the colored ink, the shrinkage direction of the colored ink is disordered in fact, that is, a large amount of colored ink does not shrink along the radial direction, and a large amount of ineffective movement exists, so that the shrinkage speed of the ink is affected, and meanwhile, the strength of the electric field at the periphery of the pixel is small due to the edge attenuation effect of the electric field, and the shrinkage speed of the colored ink is further slowed when the colored ink shrinks to the edge of the pixel, so that the shrinkage speed of the ink is also affected. When the pixel electrode removes the driving voltage, the colored ink spreads under the action of self tension, the tension direction is actually tangential to the ink surface, but not along the radial direction, the component force of the tension in other directions brings disorder of the spreading direction, so that a large amount of ineffective movement is caused, the shrinkage speed of the ink is influenced, and meanwhile, the self tension of the colored ink is smaller when the color ink is closer to the center of the pixel, the spreading speed of the colored ink is further reduced, and the spreading speed of the ink is also influenced. The response speed of the pixel brightness switching is affected by the reasons, the pixel brightness switching time is extremely short in the actual video display process, and the colored ink is often not completely paved in the whole pixel area or is completely contracted to the pixel edge, namely the next frame refreshing is carried out, so that the display effect is seriously affected. Disclosure of Invention In order to solve the defects in the prior art, the invention provides an electrowetting display with a gradient electric field, which can improve the response speed during switching of brightness and darkness. The technical problems to be solved by the invention are realized by the following technical scheme: The electrowetting display with the gradient electric field comprises an upper substrate assembly, a lower substrate assembly and a pixel layer, wherein the upper substrate assembly and the lower substrate assembly are oppositely arranged, the pixel layer is clamped between the upper substrate assembly and the lower substrate assembly, the pixel layer comprises a plurality of pixel areas which are arrayed, each pixel area is filled with a polar aqueous solution and nonpolar colored ink which are mutual