A transdermal patch for the treatment of Alzheimer’s disease includes: a backing, a rivastigmine-containing layer, a pressure-sensitive adhesive layer, and a release liner. The gamma correction unit performs gamma correction for the block image having the second value and does not perform gamma correction for the block image having the first value. Each tongue has planar top and bottom surfaces respectively oriented perpendicular to a central axis of a corresponding one of the ring openings.