| abstract |
Irregularities are formed on the surface of an article. At the top each protrusion of the irregularities, fine irregularities finer than the irregularities are formed. The irregularities are formed so that, in a unit area of the surface of the article touched by a human finger, a ratio of a contact area between the finger and the article is in the range of 35% to 90%. It is preferable to form the irregularities so that the ratio of a contact area between the finger and the article is in the range of 45% to 80%. |