Highly Transparent Lead-Free Piezoelectric Haptic Device

TL;DR

This paper presents a transparent, lead-free piezoelectric haptic device using potassium sodium niobate, achieving high transmittance and effective acoustic resonance, offering an eco-friendly alternative to traditional lead-based actuators.

Contribution

Developed a highly transparent, lead-free piezoelectric haptic device with improved optical and acoustic performance using KNN and transparent conductive films.

Findings

Achieves up to 80% optical transmittance

Generates acoustic resonance at 16.5 kHz

Produces 1.0 um displacement at 28 V

Abstract

Acoustic haptic technology adds touch sensations to human-machine interfaces by integrating piezoelectric actuators onto touchscreens. Traditional piezoelectric haptic technologies use opaque lead-containing ceramics that are both toxic and visible. We have developed a highly transparent lead-free piezoelectric haptic device using potassium sodium niobate (KNN) and transparent conductive oxide thin films. The KNN film, grown on glass, exhibits a pure perovskite phase and a dense microstructure. This device achieves up to 80% transmittance, surpassing lead zirconate titanate (PZT) thin films. It generates an acoustic resonance at 16.5 kHz and produces a peak-to-peak displacement of 1.0 um at 28 V unipolar, making it suitable for surface rendering applications. This demonstrates the potential of transparent lead-free piezoelectric actuators as an effective alternative to conventional PZT haptic actuators.