US Patent 7601080 Golf ball dimples with spiral depressions

A golf ball includes a spherical outer surface and a plurality of dimples formed thereon. The dimples have an inner land surface with at least one spiral depression either disposed or superimposed on the inner land surface to energize or agitate the airflow over the dimpled surfaces to increase the aerodynamic performance of the golf ball. The spiral depression may turn clockwise or counterclockwise and can be either spaced apart, touching or overlapping each other. While the dimples may be circular, polygonal, triangular or elliptical, dimples having a cross section greater than 0.18 inch are preferred. The dimples may also comprise spiral depressions directly on the spherical surface of the ball.