터치패널 센서전극용 음각 메탈메쉬 형성을 위한 실버 페이스트의 물성 연구

Abstract

For the touch panel, the hand of a human and an object are input devices. The panel has an intuitive interface and a simple operation method. Therefore, the effective value is high and the panel is used in many fields. ITO film is used as the transparent conductive film. However, ITO film has a problem of the rise in unit cost, a high resistance and a crack problem when doing banding, so it faces the limitation of development of the future-oriented display. Recently, the method of the metal mesh becomes the issue, which problems discussed before are the strength. The metal mesh film is the transparent conductive film which has a cross stripes which is patterned by the metal line having the conductivity in the transparent film patterns, it has the strengths such as the large-area, the flexibility, the stable unit price, the simultaneous formation of the narrow bezel. However, since the metal mesh makes the problem of Moire and the visibility which the electrode of the mesh line can be seen, the line width line of the electrode should be micro. Also, it is not easy for the mold of the micro line width to charge and the mold requires the new rheology property unlike the existing paste for the printed electronics. The purpose of this paper is to study on the basic rheology by making the paste in accordance with the viscosity of the paste, the kind and the content of the solvent and the kind of the silver powder for the design of the paste for the intaglio metal mesh. Scanning electron microscope(SEM) was shot after forming the metal mesh by directly charging the manufactured paste in the mesh mold. The relationship with the charge amount in SEM picture was figured out by analyzing the graph of the viscosity and the viscoelasticity after measuring the rheology of the paste. Also, after doing screen printing of the paste and drying it, the specific resistance was compared. As a result, it was confirmed that the paste having the low viscosity and TI has the large charge amount through SEM. In the viscoelasticity graph, it was also confirmed that having the viscous property has the large charge amount. Therefore, the paste has a good flowability and has a large charge amount. It was confirmed that the particle diameter of the silver powder should be small to fill in the mold of the micro line width. However, when the particle diameter was small, the paste has no good flowability. Therefore, the improvement was needed. When the particle diameter of the silver was small, the specific resistance had a large value and unexpectedly, the paste using the particle diameter of the nano size had the most excellent conductivity. I think that it is because the nano particle is filtered in the low temperature.