US6337129Nov 30, 1998Jan 8, 2002Toto Ltd.For imparting such a property that stains, such as deposits and contaminants, are less likely to be depositedUS6524664Aug 13, 1999Feb 25, 2003Toto Ltd.A photocatalyst is formed on a substrate fixed with hydroxyl group upon photoexcitation; water molecules are physically adsorbed in the vicinity of the hydroxylsUS6606869 *Jul 26, 2002Aug 19, 2003Sanyo Electr