Hydrophobic dielectric layer of composite layer structure, its preparation method and electrowetting device

Abstract

The invention provides a hydrophobic dielectric layer in a composite layer structure, a preparation method thereof and an electrowetting device. The hydrophobic dielectric layer comprises a dielectric layer and a hydrophobic layer arranged on the upper surface thereof. The hydrophobic layer is made of a hydrophobic polymer. The dielectric layer contains the same hydrophobic polymer as the hydrophobic layer. The hydrophobic polymer of the dielectric layer is doped with surface-modified inorganic oxide particles. Through the dielectric layer, the dielectric constant of the hydrophobic dielectric layer can be effectively improved, and the application voltage of the electrowetting device is greatly improved. The application range of the electrowetting device is extended. The dielectric layer is used as the hydrophobic dielectric layer alone. If the inorganic oxide particles are introduced, high hydrophobicity and low hysteresis of the polymer are affected. The hydrophobic dielectric layer can maintain high hydrophobicity and low hysteresis by arranging the hydrophobic layer on the upper surface of the dielectric layer. The inorganic oxide particles are prevented from directly contacting a conductive fluid, which can improve the stability of the electrowetting device.

Description

technical field [0001] The invention relates to the technical field of electrowetting display, in particular to a hydrophobic dielectric layer with a composite layer structure, a preparation method thereof and an electrowetting device. Background technique [0002] The principle of electrowetting technology is to use the electrode covered with the functional layer as the substrate of the conductive liquid. During the electrification process, the contact angle of the droplet on the substrate can be greatly changed. In the case of electrification, the change of contact angle and the applied voltage satisfy the Young-Lippmann equation: Therefore, in electrowetting technology, the hydrophobic dielectric layer must meet two requirements: 1. Good dielectric property and high dielectric constant. 2. Good hydrophobicity and large initial contact angle of electrolyte. 3. Low hysteresis and good recovery. In order to meet the above conditions, the current electrowetting functional...

AI Technical Summary

Problems solved by technology

Although these materials generally have the characteristics of high dielectric constant and good insulation, they are difficult to bond with conductive substrates due to their poor adhesion. Therefore, chemical deposition, pulsed laser deposition, etc. are usually used to prepare dielectric layers.

Even so, its properties are quite different from those of the hydrophobic layer, and its compatibility is not good. Bubbles, peeling, and falling off between the composite functional layers are also prone to occur, resulting in a significant decrease in device stability.

[0004] On the other hand, the surface of inorganic oxide particles is rich in oxygen polar bonds, and the phenomenon of ionization and electrolysis will inevitably occur on the surface of the electrode, which will significantly reduce the dielectric property.

Although surface modification can reduce the probability of ionization to a certain extent, as long as there is no 100% surface modification, it is still unavoidable

[0005] In addition, the doping of inorganic oxide particles will inevitably increase the roughness of the film surface, which is obviously not conducive to the high recoverability (i.e. low hysteresis) of droplets on the surface of the functional layer under the action of an electric field.

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