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Under development material


Transparent piezoelectric film (under development)

The new transparent piezoelectric film developed by Daikin features a unique property called ferroelectricity that converts force, strain, temperature change, and electrical energy in both directions. Additionally, because of its excellent transparency and flexibility, it is expected to become a key material for pressure-sensitive touch panels and wearable devices.

What is ferroelectric material?

This is a material that can maintain a polarized state (+/-) with no electric field by voltage processing and has both piezoelectricity (stress/deformation and electric signal conversion) and pyroelectricity (temperature change and electric signal conversion).

Fig.1 Ferroelectricity (piezoelectricity and pyroelectricity)



In addition to applications as optical film benefiting from its high optical characteristics (high transparency, low haze, and low birefringence), Daikin’s transparent piezoelectric film is uniquely suited for various piezoelectric and pyroelectric applications with use expected in applications including pressure-sensitive touch panels. The film features high suppleness and bending resistance that makes it useful for flexible, wearable devices.

Fig.2 External view of film


Fig.3 External view of film (high transparency)


Features and grades

- High transparency and piezoelectricity
- Greater piezoelectric heat resistance than that of stretched PVdF (see Fig.4).
- Isotropy (differences in physical properties are small between vertical and horizontal in-planes [birefringence, d31 ≒ d32])
- Reliability
 - High temperature and high humidity tests: No significant deterioration at 85℃/85RH% x 240 hr
 - Heat shock test: No significant deterioration at -40℃ ⇔ 85℃ x 200 cycles
 - Low heat shrinkage: 0.9% or less in 75℃ x 1 hr test, especially 0.2% or less in the Y40-T
- High-quality film with few fluctuations and defects due to Daikin’s unique continuous processing technology
- Roll specifications (width [mm]: 500, length [m]: 50-300)

* Resin is also available.

Table.1 Physical characteristics / functions of piezoelectric film (under development)


Fig.4  Electrical properties of transparent piezoelectric film (development product)

(Aging of d33 at 90°C)


Fig.5 External view of roll


Expected industries and applications

- Human Machine Interface (HMI) in information terminals/ PCs (flat keyboards such as dual displays and folding devices, proximity sensors, and ultrasonic sensors)
 : Transparent and highly sensitive piezoelectric and pyroelectric films
- Automotive (e.g., navigation touch panels, seat sensors, and collision impact sensors)
 : Film that excels in design
- Healthcare (sleep sensors for mattresses, pulse/heart rate sensors)
 : Film with excellent flexibility and durability to repeated stress

- FA / industrial equipment (equipment abnormality [vibration] sensors)

Fig.6 Expected industries and application examples


All the data shown in this report are not guaranteed.

In addition, this material is intended for general industry, and therefore its adequacy and safety as a raw material for medical purposes cannot be guaranteed.

Please let us know your opinions and impressions about this product.




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