A sensor arrangement for determining the CO2 concentration in an interior space has an NDIR sensor unit that can determine the number of CO2 molecules on an optical measuring section and therefrom the CO2 concentration in an interior space. The image forming apparatus converts connection information for connecting to the image forming apparatus by a WLAN scheme into a corresponding image pattern, and displays the image pattern on a display unit. Therefore, even when the ion current contains a discharge noise component, the discharge noise component having a short duration accounts for only a small portion of the cumulative value, so that the influence of the discharge noise component on misfiring detection can be reduced. A displacement calculating unit calculates displacements between images regarding multiple first images. The vehicle-side transformer part couples with a charging station-side transformer part through the license plate when the charging station-side transformer part is arranged in front of the license plate such that electrical energy can be transferred through the transformer parts to the vehicle. The optical train is configured so that light encounters the dispersive element and the wave plate twice before reaching any of the output ports.