Patent ID: 8389885

Claim:
A dome shaped spring comprising: a dome shaped spring section configured to buckle when pushed, and a substrate in contact with an edge section of the dome shaped spring section, wherein: the dome shaped spring section includes a movable portion when buckling of the dome shaped spring section occurs, and the movable portion includes a neutral face having an aspherical shape, the aspherical shape is represented by an even function of at least six degrees, and an angle α and an angle β satisfy a relation of α<β, the angle α being an angle between (i) the dome shaped spring section at an inflection point of the even function corresponding to a position between a center and an outer diameter of the dome shaped spring section and (ii) the substrate, and the angle β being an angle between (i) the dome shaped spring section at an inflection point of the even function corresponding to the outer diameter of the dome shaped spring section and (ii) the substrate.