The Cornell researchers created an optical fiber sensor using LEDs and inexpensive dyes that resulted in a stretchy skin-like material capable of detecting distortions, including compression, bending and tension. The sensor can contain soft robotic systems applications and can be a game-changer for augmented reality technology. The soft, wearable sensor can allow augmented reality users to experience sensations similar to those experienced in the real world.
Technology It has other applications as well, and researchers are currently working to commercialize the technology for use in physical therapy and sports medicine. Their work is based on the work of an earlier stretchable sensor built in Rob Shepherd’s lab, who also led the team in the new research.
The stretchable sensor was created earlier in 2016 and used light transmitted through an optical waveguide and a photodiode to detect changes in beam intensity to determine when the material was deformed. For the new project, researcher Hedan Bai drew inspiration from distributed optical fiber sensors based on silica capable of detecting subtle shifts in wavelength as a way to define multiple properties, including changes in humidity, temperature and pressure.
Silica fibers are incompatible with soft and stretchy electronics. The solution was to create an SLIMS stretchable optical guide. This is a long tube that contains a pair of flexible polyurethane cores. One core is transparent, and the other is infused with absorbent dyes at multiple sites and connects to an LED. Each core is paired with a red, green and blue sensor chip that is capable of recording geometric changes in the optical path of light.
The use of a dual core design increases the number of outputs the sensor can use to detect a range of distortions, including compression, bending or elongation. It indicates distortions by illumination of the dye, which acts as a spatial encoder. The technology is coupled with a mathematical model that is able to separate and accurately determine their location and size of various distortions. SLIM sensor can work with small, low-resolution optoelectronics, making it less expensive and easier to manufacture and integrate into systems. This sensor can be integrated into the hand of a robot to detect wearable or slip gloves for VR / AR users.