A grout sealer applicator increases efficiency in applying sealer to grout. An optical axis of light incident on the color separation optical member forms an angle smaller than 45 degrees with a normal to a light incident surface of the color separation optical member. A gain of data to be displayed at a second position of said field is controlled into a second gain value. 11bg-compliant Access Point functionality. The hydroxycucurbituril derivative is easy to further functionalize with enhanced solubility in common solvents, thereby providing wider applications.