A thermoplastic resin-coated aluminum plate is provided which is less liable to develop ply separation or cracks in a resin coating film during drawing or ironing and on which the resin coating film is less likely to peel off the aluminum plate. The robot arm unit includes at least one bearing platform and at least one level sensing structure disposed on the at least one bearing platform. When extracting each of the display images, a region of the display image extracted from the upper viewpoint image is expanded beyond the size of a standard extraction region on the basis of the set height of a mating face. The presence of the target substance modifies the expected photo-induced charge movements produced by the sensing surface upon illumination.