A securing element for protecting against an unintentional release of a plug connection between a cable harness plug and a coupler plug. A photosensor is provided in each of a plurality of pixels arranged in a matrix, each pixel accumulates electric charge in a data holding portion for one frame period or longer, and an output of the photosensor changes in accordance with the electric charge accumulated in the data holding portion. 5 to 20 molar parts of RE is contained with respect to 100 molar parts of the primary component. The power of the signal inside the animal is greater than that outside the animal since the signal is attenuated by the structure of the animal.