Image Number 4 for United States Patent #5556194.
The front opening of a lamp space with a bulb disposed therein is covered with a lens. The lens is segmented into five sectional areas. Cylindrical steps of which the axes are vertically oriented are formed on the rear side of these sectional areas. These cylindrical steps are arrayed in a zig-zag fashion such that the cylindrical steps in adjacent sectional areas are shifted from each other approximately half the width of a single cylindrical step.