Crack-inducing Strain Sensor Array using Inkjet-Printed Silver Thin Film for Underplate and Off-centered Force...

Area of Science:

• Materials Science
• Nanotechnology
• Sensor Technology

Background:

• Metal film sensors for force touch applications often have limited sensitivity, necessitating complex readout circuits.
• Existing sensors struggle with detecting subtle forces, impacting performance in applications like fingerprint recognition and wearables.

Purpose of the Study:

• To enhance the sensitivity of metal film strain sensors for force touch applications.
• To develop a highly sensitive, crack-based strain sensor using inkjet-printed silver thin films.
• To demonstrate the sensor's capability in detecting weak forces through various materials and its potential in wearable technology.

Main Methods:

• Inkjet printing of silver thin films on substrates with crack-inducing underlayers.
• Fabrication of flexible strain sensors capable of detecting resistance changes under deformation.
• Testing sensor performance with varying force levels and through different force-receiving layers (PET, glass).

Main Results:

• The developed sensors exhibit significantly increased sensitivity to resistance changes upon deformation.
• The crack-based sensors can detect forces as low as 10 gf, suitable for fingerprint recognition.
• Accurate detection of wrist artery pulse patterns was achieved even with off-centered sensor placement, demonstrating wearable device potential.

Conclusions:

• Inkjet-printed silver thin films with crack-inducing underlayers offer a highly sensitive strain sensing solution.
• These sensors overcome limitations of traditional metal films, enabling detection of weak forces through various materials.
• The crack-based sensor technology opens avenues for advanced wearable devices and hidden user-machine interfaces.