Shilma mask research
The Shilma mask has been tested by the National Institute for Laser, Plasma and Radiation Physics, Bucharest, Romania, Laboratory of Solid-State Quantum Electronics using a schlieren interferometer built by Dr. Ciprian Dumitrache (Senior Researcher, CSIII).
The schlieren visualization technique enables the visualization of transparent phenomena (such as human breath or cough) in a non-invasive manner purely due to changes in the index of refraction of the media.
The physical phenomenon is based on light diffraction. A small change in fluid temperature (exhaled air comes out slightly hotter than surrounding air) leads to slight change in the index of refraction. Light rays coming from an incoherent light source are bent when traversing this perturbed media and are subsequently steered away from their nominal (unperturbed) focal spot. A razor blade is placed at the focus in order to selectively block the light rays thus allowing invisible optical phase disturbances to become visible to the human eye. The darker/brighter streaks (“schliere” in German) seen in the videos below are nothing more than “fingerprints” of the disturbances encountered by the light rays in their path from the source to the detector.
Videos show air currents generated by human (young male in his 30s) breathing and speaking in 2 different scenarios:
- With surgical mask
- With Shilma™ mask design
Breathing tests performed on Shilma and surgical mask
Speaking tests performed on Shilma and surgical mask
It becomes readily apparent that, while the regular masks direct most air upwards (straight into the path of the eyeglasses), the Shilma transparent mask conveniently steers the air towards the lower body. This significantly reduces the spread of germs and, also, the fogging of sunglasses or eyeglasses.