A domestic research team has developed a fingerprint sensor that can significantly reduce thickness and expand the recognition range compared to existing ones. Since the materials are easy to obtain and existing manufacturing processes can be utilized, it is expected to be advantageous for rapid commercialization.

The Electronics and Telecommunications Research Institute (ETRI) announced on the 1st that it has developed a fingerprint sensor that can improve the performance of fingerprint recognition sensors in collaboration with Pohang University of Science and Technology (POSTECH) and electronic component manufacturing company CLAP.

The research team was able to achieve results by creating an electrode structure that can utilize organic matter and light more effectively.

This achievement was recognized for its excellence and published in 'Materials Horizons', an international academic journal in the field of materials engineering published by the Royal Society of Chemistry.

Unlike passwords or public certificates, biometric technology is highly secure because it utilizes unique physical characteristics.

Among these, fingerprint recognition technology is rapidly expanding its application areas, including ATMs and smartphones, due to its low user resistance and fast recognition speed.

Fingerprint recognition is mainly done by shining light on the hand and using a sensor to collect the shade that changes due to the curve of the fingerprint and extracting an image.

This type of device is largely composed of a photosensor and an oxide thin film transistor array.

The light sensor converts light shading into electrical energy, and the oxide thin-film transistor array uses the electrical energy to extract a fingerprint image.

Previously, silicon was mainly used to make optical sensors.

On the other hand, the research team achieved innovation by using organic materials doped with a substance called bis(fluorophenyl azide).

Because organic materials have a greater light absorption capacity than silicon, optical sensors can be made with a thickness smaller than that of silicon.

Additionally, silicon is colored to distinguish the wavelengths of light it can absorb.You may need to add a filter, but organics do not need to.

Thanks to this, not only can the sensor module volume be reduced while significantly reducing the thickness, but also interference between elements can be reduced, which is advantageous for manufacturing film-type fingerprint sensors.

Additionally, the research team developed a triple-layer upper electrode composed of molybdenum oxide/gold/molybdenum oxide to create a light sensor that receives light from above.

This is a structure that reduces thickness and allows for more light to be received compared to the existing method of receiving light from below.

Applying this technology can significantly reduce the volume required to create a fingerprint sensor while maintaining high performance.

It can be used in various ways, such as providing fingerprint recognition function on the entire screen, not just a part of the screen.

Additionally, it is evaluated that rapid mass production is possible because it can be manufactured using existing and widely used manufacturing processes.

ETRI Senior Researcher Park Young-sam stated, "We developed the fingerprint recognition sensor with commercialization in mind, ensuring practical use. We hope that the high-performance film-type fingerprint sensor we developed will be applied to various industrial settings, such as mobile phones, laptops, and ATMs, enabling citizens to achieve easy and secure authentication."

Professor Dae-Sung Jeong of POSTECH said, “Printing-based fingerprint recognition sensors that can be introduced to the front of portable electronic devices are currently of keen interest to all electronics companies. “I hope that this technology can be applied to achieve various innovations,” he said.

This study was conducted as part of the ICT R&D Innovation Voucher Project of the Ministry of Science and ICT's Information and Communications Technology Planning and Evaluation Institute.

The lead company is CLAP, an electronic components manufacturing company, and the co-first authors of the research paper are ETRI Senior Researcher Joo-Cheol Woong and POSTECH PhD candidate Joo-Hee Kim, and the co-corresponding authors are ETRI Dr. Young-Sam Park and POSTECH Professor Dae-Sung Jeong.