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Wearable sensors and actuators to monitor and promote physical and emotional wellbeing

Periodic Reporting for period 1 - BEWELL (Wearable sensors and actuators to monitor and promote physical and emotional wellbeing)

Reporting period: 2019-01-01 to 2020-09-30

BEWELL project is about developing integration and manufacturing technologies needed for smart skin patch and wrist-device wearable electronics sensing and actuating products. BEWELL project is also about demonstrating three different application use cases.

Wearable electronics belongs to new age consumer electronics together with smartphones, gaming consoles and laptop/tablet computers. Key development focuses of the new devices are better human-machine interfaces, improved connectivity, user-friendly form factors and convenience of use. Internet of things, connected living, quantifed self and smart homes are identifed as the driving trends of this evolution among which especially the quantifed self is clearly driving the wearable electronics. Inside wearable electronics, wrist-worn devices have been the largest segment but body-worn and head-worn devices are expected to grow to similar sized segments.

Intimate skin contact is necessary for reliable sensing and actuation based on sensor results during different levels of activity of the users. Controllable skin contact would be a further improvement in sensing applications. The purpose can be to replace or supplement visual messaging. Therefore, skin patches and associated technologies to enhance the user-device interface also in other types of products such as the wrist-worn ones are of special importance. In BEWELL, we have identified commercially relevant future skin-patch products to be demonstrated. We have also identified a set of critical and versatile technologies that need to be developed for scalable manufacturing and integrated to realize these future products. In particular, the BEWELL project aims to unleash the potential of flexible and wearable electronics for physical and emotional wellbeing by advanced integrated technology components made in Europe.

The overall objectives are as follows.

Demonstration of three different product use cases. Two use cases are skin patches and one use case is a wristband. The skin patches integrate (i) power from primary or secondary battery and a photovoltaic, (ii) visual indicator or display elements, (iii) a decoration layer, (iv) biosignal measurements such as bioimpedance, galvanic skin response, ECG and body temperature and (v) haptic user feedback. Application cases for the patches are in emotional sensing and skin health measurements.

Haptic large-area actuator array integrated on flexible substrate together with organic multiplexing/addressing circuitry combined with IC and later thin-film driver electronics.

Flexible haptics driver based on large-area thin-film IGZO technology will be developed to replace the IC chip of the previous objective on the controller layer in order to enhance flexibility and reduce system thickness and cost.

Skin adhesion technology that provides adequate adhesion and the needed sensing and actuation contacts to the skin.

Flexible Plastic injection moulding of the actuators and sensors.

Flexible primary and rechargeable batteries optimized for the skin-patch use.

Novel electro-active polymer solutions to optimize the comfort of wear.

Integration technolofies to improve the flexibility and stretchability of the wearable solutions.
Demonstrator designs for Generation 1 are finalized. Several functionalities have already been tested separately and also as integrated with other interfacing functions. The experiments directly tight to the demonstrations thus far include (i) electrode layer tests, (ii) electrically testing haptic elements and arrays and mechanically integrating the elements with skin-contacting parts, (iii) first versions of skin-contacting layers are developed, (iv) the photovoltaic, display layer and decoration layer integrated together. Early mock-up demonstrators were presented in the EC workshop on Smart Bioelectronic and Wearable Systems in M10.

Single-element haptic actuators have been developed to be used in the patch demonstrators. Array actuators have been developed and tested as driven by a commercial driver up to 4 elements. Foil-integrated OTFT addressing circuitry is designed and is currently being implemented.

The flexible haptics IGZO driver has been designed, implemented and tested for 20 V operation. Work is ongoing to achieve higher operation voltage.

New skin adhesives have been developed to match the application requirements of the patch products. The adhesives are tested as worn on skin. Optimization is still ongoing.

First rechargeable printable Li-ion battery based on PEO/LiTFSI membrane has been demonstrated. Cycling tests up to 150 cycles have been done.

Solutions to integrate bare-die ASIC components on flexible and stretchable substrates have been tested.

Flexible perovskite photovoltaic has been demonstrated for module efficiency of about 12 % and open-circuit voltage of about 7 V.

Integration of the flexible haptics foil, battery, display and PV module has been achieved. Full-stack integration of the skin patch consisting also the electronics engine and skin-contacting parts has been tested using early versions of the different functionalities.

Market analysis and use-case designs have been done and utilized in demonstrator specifications and design.
Results now and expectation (impact):
The first Flexible Perovskite Solar Cell with round-shape is generated specially for BEWELL to be integrated with other parts of full device in order to charge the battery in sun light as well as indoor light conditions. (New energy-autonomous wearable products also for low-light conditions possible.)

First printed LIB having a quasi-solid electrolyte. First cycling tests successful already. Sealing can be used for other battery systems as well. (Same as above.)

IGZO thin-film logic on flexible substrate interfacing between low-voltage silicon IC and flexible high-voltage OTFT electronics and haptics. (New level of flexible integration of complex products for wearable form factor.)

A custom GSR mode was implemented in new version of an existing ASIC. It significantly improves the functionality of the ASIC, now having an additional read-out modality but keeping the footprint the same. (New applications.)

Co-integration of haptics and OTFT. (Same as for IGZO)

Use of low voltage flexible piezo actuators for haptic interaction with users. (New wearable functionalities.)

Integration of haptics on fabrics. (New application field for haptics.)

Skin patch that consist of a special adhesive that improves the wearability of the patch. (Better acceptance of products on market.)

First integration of Functional Crystals with printed LED layer and printed Perovskite Solar Cell (PSC). (New user interfaces.)

New or further optimized filter coatings for Functional Energy Crystals – allowing for charging of solar cells with high energy efficiency. (New level of integration possible.)

Reliable electrical vias on TPU proven in stretch testing and used to implement a stretchable skin electrode layer of the skin patch. (New structural solutions towards stretchability.)

Bare-die assembly on flexible substrate achieved for 100 um pitch. (Thinner and more flexible and stretchable products with better wearability.)

Proof-of-concept for combination of bio-signal measurements (ECG and GSR) in different body locations: e.g. wrist, shoulder, chest. (New applications.)
Schematic stack structure of the skin patch
ECG measurement result for the tested skin contact layer
First integrated skin patch
Measurement results for flexible perovskite photovoltaic
Cycling test for printed lithium-ion battery
Skin-contact layer under testing
Wrist band concept.