A Wireless Stress Mapping System for Orthodontic Brackets Using CMOS Integrated Sensors

作者：Kuhl Matthias^*; Gieschke Pascal; Ros**ach Daniel; Hilzensauer Sascha A; Panchaphongsaphak Thanapon; Ruther Patrick; Lapatki Bernd G; Paul Oliver; Manoli Yiannos

来源：IEEE Journal of Solid-State Circuits, 2013, 48(9): 2191-2202.

DOI：10.1109/JSSC.2013.2264619

• Automatic gain tuning
• biomedical devices
• CMOS integrated circuits
• CMOS MEMS
• differential difference amplifier
• load modulation
• microcoil
• orthodontic bracket
• piezo FET
• RFID
• stress mapping
• stress sensor
• variable gain
• wireless

A wireless stress mapping system for the development of %26quot;smart brackets%26quot; is presented. The system is designed for monitoring the forces and moments applied to individual teeth during orthodontic therapy which may contribute to improve treatment effectiveness. It comprises a stress mapping chip fabricated in a 0.35-mu m process and a micro coil produced by gold electroplating in a photoresist mask. Twenty-four transistor-based stress sensors for measuring either in-plane shear stress or the difference of in-plane normal stresses are strategically distributed over the chip area. The sensor signals are processed by a variable-gain differential difference amplifier and digitized by a 10-bit SAR ADC, enabling a resolution down to 11 kPa at highest gain. A wireless interface conditions the energy received at 13.56 MHz and transmits the data by load modulation. With dimensions of 2 x 2.5 x 0.73 mm(3) and a power consumption of 1.75 mW, the system lays the foundation for the assembly of smart brackets as innovative tools in orthodontic therapy.

• 出版日期2013-9