US Patent 9010029 Self cleaning shield

A gutter guard device is provided for preventing material from entering a gutter to which the gutter guard device is mounted. The device includes a stand alone filtration element configured to be mounted to the gutter. The filtration element has a substantially planar surface formed from a plurality of threads, the substantially planar surface having a longitudinal edge configured to be positioned substantially parallel to a longitudinal direction of the gutter; and a downward extending channel having a longitudinal direction that is obliquely oriented relative to the longitudinal edge of the substantially planar surface.