An apparatus for bonding two substrates includes a first roller, a second roller that forms a nip with the first roller, a substrate transport configured to move the first substrate and a second substrate through the nip simultaneously, and a controller. The waveform display device for executing waveform display of waveform data on a display section comprises an input section for inputting at least two data ranges of the waveform data, and comparison waveform display means for executing waveform display of the waveform data while overlaid on one another on the display section based on at least two data ranges inputted by the input section. Advantages associated with the method include not only the ability to produce a detector of the requisite film quality, but one which satisfies the temperature coefficient of resistance and fabrication temperature constraints.