Date

Place

[P1-137]
14:00 ~ 15:30
Title:Dependence of Sensing Signal on the Resistance of Bus Lines
In Hye Kang, Seung Jae Moon, Jin Kook Kim (Hoseo Univ., Korea), Jun Seok Lee, Ho Sik Jeon (CrucialTec Co., Ltd., Korea), and Byung Seong Bae (Hoseo Univ., Korea)
Abstract: Recently, smart phones and tablet PC are using fingerprint recognition technology. And also they suggested the fingerprint recognition on a display. However, adding a device for the fingerprint on the display in a mobile device has a problem that increasing the volume and thickness. Therefore, there is a need for technologies that reduces an extra space for the fingerprint recognition sensor and do not interfere with the display of a mobile device. The TFT based sensor circuits on a glass have been developed because Si-wafer based process is relatively complex and expensive. The TFT based sensor circuit has advantage of transparency compared to the Si-wafer and transparancy can be improved by using transparent electrode. We compared the sensing signal between the metal wire and ITO wire. ITO increases transparency of the sensor array, however, it has disadvange of RC delay increse due to higher sheet resistance than the metal. Readout voltages are sensing voltages and R means ridge and V means valley of the figerprint. Scan pulse delay is larger for the ITO wire and figure shows the larger RC delay for the ITO. Even though the RC delay is larger for the ITO, it did not affect much the output waveform.
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