A transparent electromagnetic shield to protect solar panels and the like from
dust deposition. The shield is a panel of clear non-conducting (dielectric) material
with embedded parallel electrodes. The panel is coated with a semiconducting film.
Desirably the electrodes are transparent. The electrodes are connected to a single-phase
AC signal or to a multi-phase AC signal that produces a travelling electromagnetic
wave. The electromagnetic field produced by the electrodes lifts dust particles
away from the shield and repels charged particles. Deposited dust particles are
removed when the electrodes are activated, regardless of the resistivity of the
dust. Electrostatic charges on the panel are discharged by the semiconducting film.
When used in conjunction with photovoltaic cells, the power for the device may
be obtained from the cells themselves. For other surfaces, such as windshields,
optical windows and the like, the power must be derived from an external source.
One embodiment of the invention employs monitoring and detection devices to determine
when the level of obscuration of the screen by dust has reached a threshold level
requiring activation of the dust removal feature.
