Working with the NanoFab engineering staff, researchers from WCH Technologies Corp., Potomac, Md., have developed 100 millimeter-diameter quartz wafer prototypes of a potential replacement for conventional windshield wipers. Their approach uses an electrostatic field to move water across a glass or quartz surface faster than conventional wipers and uses a fraction of the energy.
In the center region of each wafer are 128 wires made of transparent indium tin oxide (ITO), each 25 nanometers by 200 micrometers wide. Voltage is applied to the wires giving them alternating positive and negative charges. The entire wafer is covered with a transparent insulating surface layer. As water aggregates on the surface, it is attracted to the embedded wires. A computer controls the voltages, creating a varying electric field that applies a force to the water, causing it to move rapidly off the surface.
Windshield wipers were invented in 1903, and have had only two significant upgrades since then—the introduction of power wipers in the 1920s and of intermittent wipers in the late 1970s. Five years ago, CEO Walter Hernandez, a physicist, decided to try to build a wiper without vision-obstructing moving parts that could rapidly clean a whole windshield in heavy rains.
After testing dielectric samples made at the University of Maryland, Hernandez and his team came to the CNST NanoFab with their design. They worked with the NanoFab staff to develop a fabrication process and to make prototypes, using the NanoFab's plasma-enhanced chemical vapor deposition tools and other equipment.
"I didn't have expertise for making nanofabricated devices," Hernandez explains. "I worked with the staff to develop the production steps, and the technicians did the fabrication work, including all the lithographic etching. They outlined the steps and at the end the work came out exactly as specified."
Because his technology has no moving parts, Hernandez believes it may find early use in airplanes. He is developing an agreement with a windshield manufacturer to build a full-size windshield using his imbedded technology and expects a patent on his device to be issued in the next few months.