A distribution of bending principal strains giving a target shape of a curved surface is obtained, and a calculation grid is divided along the direction of the bending principal strains. Solving MeansAn optical system in which arrangement is made so that at least part of a light path of reference light for reproduction is redundant with a light path of reproduction light, and a means to let through the reproduction light and shut out reflected light of the reference light for reproduction, which is reflected by a storage medium on the redundant path are provided. Suppression of muscle contractions may be desired in situations of pathologically hyperactive muscles, such as in conditions of muscle spasm or muscle dystonia. The sheet-like portion is connected to a first surface of the semiconductor chip for holding a drain electrode.