PURPOSE: To correctly measure real surface roughness of a transparent body such as glass, a transparent plastic sheet and others by previously forming a thin electroless plated film on a surface to be measured at the time of measuring the surface roughness by an optical method.
CONSTITUTION: An article 11 to be measured is constituted of a transparent body such as transparent glass or a plastic sheet or a laminated body with these transparent bodies and metal. On a surface 11a of the body 11 to be measured a thin electroless plated film 12 is formed. The plated film 12 has a same irregular state on its surface which correctly takes an irregular state of the surface 11a to be measured. As a metal constituting the plated film 12, nickel, copper, silver and others can be considered of, and for formation of the plated film 12, acidic bath, alkalic bath and others are used. After forming the plated film 12, by making the surface as a new measured surface, surface roughness is measured under an optical method, that is, in a non-contact type. As a measuring method in this case, a laser pickup method, light interference method, a confocal method, a magic mirror method and others can be adopted.
ICHIKAWA RINJIRO
TSUBOI HARUYASU
