Curved surface shape inspection method, fiber optical block, and curved surface shape inspection device

A curved surface shape inspection method, wherein

• a fiber optic block formed by bundling and integrating a plurality of optical fibers each composed of a core region and a clad region surrounding the core region, and comprising an at least partially curved convex input end face composed of one end of each optical fiber and an output end face that is positioned on the opposite side to the input end face, is prepared for a to-be-measured object including a measurement surface having a curved concave surface shape;
• the input end face of the fiber optic block and the measurement surface of the to-be-measured object are pressed against each other, and
• an optical image formed by bringing the input end face into contact with the measurement surface and output from the output end face of the fiber optic block is used to inspect the curved concave surface shape of the measurement surface of the to-be-measured object, wherein
• the measurement surface of the to-be-measured object is an inner surface of a groove included in the to-be-measured object, and
• the optical image output from the output end face of the fiber optic block includes two contact portion images corresponding to the two respective contact portions of the input end face and the measurement surface, and wherein
• the distance between the two contact portion images is measured to inspect the curved concave surface shape of the measurement surface of the to-be-measured object.