Electro acoustic guitars have a built-in device that picks up the vibration and sound of strings, called a "pickup," in an acoustic guitar, and can be connected to an amplifier like an electric guitar to produce loud sounds.

The jointly developed contact sensor uses a newly developed "YUPO with piezoelectric characteristics" as a piezoelectric element that converts the vibration of the strings and body into electrical signals. By using YUPO, which has thin and soft material characteristics, this sensor has higher sensitivity and wider band reproducibility than conventional sensors using ceramic piezoelectric elements, and the vibration of the instrument body caused by playing the guitar can be more faithfully converted to an electrical signal. Electro acoustic guitars equipped with this sensor as a pickup reproduce the feeling of space and delicate sound created by the unity of string vibrations from the sound hole that could not be picked up by conventional pickups, the lingering sound of each string, the feeling of touch from fingering, and the overtone component in the high range, evoking the sensation of playing an acoustic guitar with a live sound.

YUPO is a film-based synthetic paper that uses polypropylene resin and inorganic filler as the main raw materials and has excellent durability and water resistance. YUPO uses a unique manufacturing method (biaxial orienting film method) that has acquired a number of patents in Japan and abroad. Numerous small voids (hereinafter referred to as "microvoids") are created on the surface and cross-section, and these microvoids realize "opacity" and "printing and handwriting suitability" that are the characteristics of paper.

Yupo Corporation has optimized the shape and arrangement of these microvoids using "microvoid control technology" cultivated over many years of research and development. Through joint research and development with Kobayashi Riken, we discovered that the microvoid walls became charged through a special charging process, and that YUPO can act as a thin, soft, and durable piezoelectric element with high sound collection sensitivity. After that, we started joint research and development with Yamaha and Kobayashi Riken for practical use in 2013, and the product will now be used as a contact sensor for the pickup system for the electro acoustic guitar "FGX/FSX" in the "FG/FS Red Label Series" to be newly released by Yamaha on Saturday, May 25, 2019. Red Label

• * Atmosfeel is a coined word combining "Atmosphere" and "Feel."

Going forward, Yupo Corporation will continue to research and develop Yupo's piezoelectric properties and consider applying it to new piezoelectric sensors. We will continue to create new value and contribute to the development of a prosperous society by using YUPO's unique material properties as a functional synthetic paper that combines the features of paper and film.

Reference materials

Figure 1) Schematic image of YUPO's structure

YUPO is a three-layer synthetic paper with a base layer laminated with a surface layer.
Light is irregularly reflected by countless microvoids (tiny holes) generated in the surface layer during the stretching process,
realizing high whiteness, printability, suitability for handwriting, and light weight, while strength is ensured by the base layer.

Figure 2) Image of YUPO functioning as a piezoelectric element in a contact sensor.