Recently, an online shopping mall is being invigorated. Nevertheless, many people still prefer offline shopping. It is mainly because we cannot check on the texture of the clothes. However, ETRI (Electronics and Telecommunications Research Institute) develops a technology to solve this problem.

The technology of ETRI is telehaptics. The main principle of it is similar to the one of telephone. How can one hear the voice of a person from a long-distance? It is possible due to a microphone and a speaker. The sound waves from speaking make a magnet or a coil vibrates, and the microphone converts them to the current signature by electromagnetic induction. Then, an amplifier amplifies this information and delivers it to a speaker as a counterpart.

▲ microphone and speaker for telephone

Like telephone, a telehaptics is possible when a mechanical pressure converts to an electric signal, and the signal also converts to pressure as a counterpart. The device for this process is a circuit element called piezoelectricity. This device measures the physical quantity by converting the pressure to an electric signal. How does piezoelectricity work? First, the mechanical pressure is applied to a material that does

▲ the principle of piezoelectric

not conduct an electric current before. Then, the pressure forces the electric charges within the crystal out of balance, and the metal plate which surrounds the material collects these charges, which can be used to produce a voltage. After a series of processes, we just need to convert signals to pressure and send it to a piezoelectric element actuator for the system of telehaptics.

ETRI made piezoelectricity with flexibility and world-standard piezoelectric performance.

▲ telehaptics of ETRI

The piezoelectric element actuator is the key element for response time and high quality of output. One of the most important elements for communication from a long distance is response time. It takes 1 ms (millisecond) for a person to sense the touch. Compared to this, the response time of telehaptics is just 200 μs (microsecond). Therefore, we can perceive the touch without a delay. Moreover, ETRI applies the structure of multimorph to actuate and make a high quality of output.

by Jiho Kim