Telehaptic device transmits tactile sensations in real time

Through tactile collection sensors and tactile reproduction actuators, the device allows people to feel textures virtually without touching objects in reality.

The telehaptic device works by being attached to the fingertip like a sticker and leverages the unique vibration pattern of touch and texture. By having this close contact with the skin, it is able to provide a more vivid tactile experience and bridge the immersion hindrance of other similar devices. 

The technology, developed by ETRI engineers, is expected to add a sense of immersion to the metaverse.

"Through the light and flexible on-skin tactile reproduction device that can be attached to the skin, we have taken a step forward in preparing a foundation environment for developing highly immersive virtual/augmented reality content," said Hye Jin Kim, the lead researcher on the project.  

To build the device, the research team used a self-developed piezoelectric element and an ultra-thin flexible substrate, which was able precisely integrate microscopic sensors and actuators of less than 1mm on the substrate.

The substrate is thin and bendable with a thickness of 1/20 of a human hair (about 4㎛). The high-resolution composite sensor, which is finely structured at 1.8 mm intervals, can feel tactile patterns in a wide frequency range of 1 ~ 1,000 hertz (Hz).

The device proved to be successful in the tests made by the team, by being able to simultaneously measure both slow-changing pressure (static pressure) and fast-changing pressure (dynamic pressure).

The technology is so accurate it can reproduce materials such as cotton, polyester, and spandex, as well as the shape of convexly protruding letter surfaces and the dynamic feeling of plastic rods rolling on the fingertips.

The sensations can be transmitted in real-time, at a distance of up to 15m using Bluetooth communication.

During tests, the delay time when transmitting the tactile/texture data signal was only 1.55 milliseconds (ms), and the acquired and reproduced signals matched approximately 97 per cent, according to the researchers. 

In the future, the research team reportedly plans to innovatively advance the performance and form factor of the piezoelectric element to create complex tactile and texture levels that match reality by combining not only vibration but also various tactile stimuli.

In addition, they plan to implement more realistic complex sensors to add heat and cold sensations.

The details of the technology were described in an article published in NPJ Flexible Electronics.