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Visible ITO Pattern in Capacitive Touch Lens: Cause and Countermeasure

Published online by Cambridge University Press:  05 April 2011

Duk Su Kim ,
Gyeong-Geun Lee ,
Jacob Yang  and
Dong Hyuk Shin
Duk Su Kim
Affiliation:
R&D Center, ELK Corporation, Daejeon, Korea, Republic of;
Gyeong-Geun Lee
Affiliation:
Nuclear Materials Research Division, Korea Atomic Energy Research Institute, Daejeon, Korea, Republic of.
Jacob Yang
Affiliation:
R&D Center, ELK Corporation, Daejeon, Korea, Republic of;
Dong Hyuk Shin
Affiliation:
R&D Center, ELK Corporation, Daejeon, Korea, Republic of;
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Abstract

Market demand for touch panel/lens has been exceptionally high for the recent years due to smartphones, tablet PCs, etc. Among the available technologies to envision touch functionality, capacitive touch screen has received the great attention due to the various superiorities over the competing ones. Capacitive touch screen features two transparent conductive electrodes, such as ITO (indium tin oxide). However, the difference in refractive indices of ITO, substrate, and air, ITO pattern is clearly visible if there is no proper countermeasure. Most of touch screen makers and ITO substrate supplier utilize “index-matching technology” to prevent this phenomenon.

Even though of the attempts to minimize visible ITO pattern in final product, there are many technical and process challenges. In this study, the causes around visible ITO pattern were investigated to understand and provide the proper countermeasures.

One of the possible causes for visible ITO pattern was improper annealing process in ITO especially for film substrate. According to XPS (X-ray photoelectron spectroscopy)/ESCA (electron spectroscopy for chemical analysis) and other analysis results, ITO, which is normally deposited through sputtering, is not fully transformed to oxidized state. After aligning and adjusting annealing condition, acknowledged visible ITO pattern was disappeared.

Other causes for visible patterns were also discussed in detail, and the relevant countermeasures were provided.

Keywords

transparent conductorx-ray photoelectron spectroscopy (XPS)annealing
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1315: Symposium MM – Transparent Conducting Oxides and Applications , 2011 , mrsf10-1315-mm03-01
Copyright
Copyright © Materials Research Society 2011

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