A Flexible Piezoelectret Actuator/Sensor Patch for Mechanical Human–Machine Interfaces

Abstract

Flexible and wearable devices with the capabilities of both detecting and generating mechanical stimulations are critical for applications in human–machine interfaces, such as augmented reality (AR) and virtual reality (VR). Herein, a flexible patch based on a sandwiched piezoelectret structure is demonstrated to have a high equivalent piezoelectric coefficient of d 33 at 4050 pC/N to selectively perform either the actuating or sensing function. As an actuator, mechanical vibrations with a peak output force of more than 20 mN have been produced, similar to those from the vibration mode of a modern cell phone, and can be easily sensed by human skin. As a sensor, both the pressure detection limit of 1.84 Pa for sensing resolution and excellent stability of less than 1% variations in 6000 cycles have been achieved. The design principle together with the sensing and driving characteristics can be further developed and extended to other soft matters and flexible devices.

Interfacial Phenomena of Advanced Composite Materials toward Wearable Platforms for Biological and Environmental Monitoring Sensors, Armor, and Soft Robotics

“…Zhong et al designed a dual patch actuator and sensor based on the piezoelectric properties of two sandwiched layers of fluorinated ethylene propylene (FEP) electret film and a bubbled‐shape Ecoflex spacer, responsive to both mechanical and vibrational stimulations. Depending on the operation mode, the device an either act as an actuator to produce mechanical vibrations or measure applied strain.…”

Tailoring Artificial Mode to Enable Cofired Integration of Shear‐type Piezoelectric Devices

“…over wide bands ( Figure S9, Supporting Information). In fact, for piezoelectric sensors, charge-detection method assisted with charge preamplifiers is more effective, robust and is the mainstream technical route especially for tiny signals, where output strength is proportional to generated charge instead of voltage of sensors [48,49] (see principles in Figure 5g and Figure S10 of the Supporting Information). Since multilayer structure can greatly amplify charge response, cofired devices should heighten sensing capabilities.…”

Metamaterials-Enabled Sensing for Human-Machine Interfacing

“…Previously, people have used different functional materials to sense or emulate a wide range of mechanical stimuli such as pressure and strain, like piezoelectric materials, triboelectric materials, etc. [2,[120][121][122][123][124][125][126][127][128]. However, the soft stretching capability is one of remaining issues to be overcome that is rather preferred for practical HMI applications as rigid materials are incompatible to the skins, uncomfortable to wear, and lacking of adaptability to the dynamic motion of human body [128,129].…”

“…Ever since humans invented machines, people have begun to operate them, and in broad sense, the human-machine interaction, no matter being noticed or not, also began. The purpose of inventing mechanical machines was originally to assist humans in finishing some repeated, burdensome or dangerous processing task, and later on the concept of machine became broader to include electronic devices, which have doubtlessly changed our daily lives revolutionarily [1][2][3]. Nowadays, no one will deny that electronic machines and devices have played such an important role that they have changed, redefined, recreated the way we work, sense, communicate, entertain, travel, and interact with the world.…”

“…From the interactive approach, the HMI can be sorted into mechanical (touch, press, stretch) [3,9], acoustic (sound) [10,11], optics (light) [12,13], thermal (infrared or bionic) [14][15][16], and so on. Along with the advent of machines, people have began to interact with these machines, but the human-machine interface (HMI) concept was firstly proposed and systematically investigated in the 1980s [2]. Since then, the HMI has been attracting more sustained attention and research interest in more sensitive, flexible, and reliable interactions with machines from the perspective of materials, devices, systems, and algorithms [17][18][19][20][21][22][23][24].…”