Health and activity monitoring “patch” weighs only 10g

April 09, 2014 // By Graham Prophet
Holst Centre and imec have unveiled a prototype flexible health patch weighing 10g – half the weight of current products. The patch uses real-time electrocardiogram (ECG), tissue-contact impedance and accelerometer information to accurately monitor physical activity.

The design uses system in package (SiP) technology from Shinko Electric Industries of Japan, to yield an electronics module that measures less than two by two centimeters. High accuracy algorithms, low power consumption, and small size and weight make it ideal for consumer applications.

Activity monitors are already available that count steps taken and infer calories burnt. Heart rate is a key input in determining activity levels; hence monitors that can be worn comfortably on the chest offer the greatest accuracy. This increases the demand for small, lightweight monitors that can flex and move with the body.

Imec and Holst Centre’s patch combines ultra-low power electronics and flexible electrode technology; it includes a 1-lead ECG, a tissue-contact impedance sensor and a 3D accelerometer. Data is processed and analysed locally, and relevant information is transmitted via Bluetooth Smart (BLS). The patch acquires, processes and communicates data on a minimal energy budget, allowing extended use with smaller batteries. The Bluetooth Smart link provides a standardised communication channel to mobile devices such as smart phones and tablets.

Working with Shinko Electric, researchers from imec used Shinko’s SiP technology to integrate the functionality into a module measuring 17.4 x 17.4 mm. This represents a PCB area reduction of 52% compared to previous generations of the module. The module was then integrated into a flexible and stretchable patch designed by Holst Centre. The design combines system-in-foil technology with stretchable, integrated electrodes to create a lightweight patch that can be worn comfortably on the chest for extended periods. The module’s small size and the flexibility of the patch reduce motion artifacts and provide more accurate and reliable monitoring.

“Our technology for packaging electronic devices uses a high-density organic substrate to reduce overall system size. Thanks to the experience we’ve gained in this joint initiative with imec and Holst Centre, Shinko can accelerate the development of next-generation body area network (BAN) products,” said Tadashi Kodaira, corporate officer