US Patent 10415584 Impeller and fan using the same

An impeller for a centrifugal fan includes a base plate, a ring-shaped shroud, a tubular inlet port connecting the circular inlet of the shroud and the base plate, and a plurality of blades annularly disposed around the tubular inlet port at regular intervals. Each of the blades includes a pressurized surface, a suction surface, a leading edge, and a trailing edge. When viewed in a direction parallel to the rotation axis of the impeller, a distance between the pressurized surface and the suction surface of each of the blades becomes increasingly larger starting from the leading edge of the pressurized surface and extending toward the trailing edge of each of the blades at a predetermined height.