Patent ID: 7463994

Claim:
A method for detecting surface state of a work piece wherein: first and second measuring thermocouples in contact with a surface to be measured of the work piece are caused to perform movements with relation to the surface to be measured so that generated thermoelectromotive forces of the measuring thermocouples are measured, and a surface roughness, of the surface to be measured Ry=(α 2 ·ΔE 1 −α 1 ·ΔE 2 )/(α 2 ·β 1 −α 1 ·β 2 ) and/or a surface temperature variation of the surface to be measured ΔT=β 2 ·ΔE 1 −β 1 ·ΔE 2 )/(α 1 ·β 2 −α 2 ·β 1 ), is obtained from the measured thermoelectromotive force on the basis of first correlation data ΔE=α 1 ·ΔT+β 1 Ry and second correlation data αE=α 2 ·ΔT+β 2 ·Ry between thermoelectromotive forces, surface roughness and/or surface temperature variations; where: ΔE is the thermoelectromotive force, ΔT is the surface temperature variation, Ry is the surface roughness, α 1 is an inherent temperature coefficient of the first measuring thermocouple and the first data collecting thermocouple, α 2 is an inherent temperature coefficient of the second measuring thermocouple and the second data collecting thermocouple, β 1 is a roughness coefficient induced from the relation between the thermoelectromotive force and the surface roughness depending on the contact condition and the relative movement condition of the first measuring thermocouple and the first data collecting thermocouple, β 2 is a roughness coefficient induced from the relation between the thermolectromotive force and the surface roughness depending on the contact condition and the relative movement condition of the second measuring thermocouple and the second data collecting thermocouple, and the surface roughness and/or surface temperature variations are previously obtained by bringing first and second data collecting thermocouples, respectively, the same as or the same kind as the first and second measuring thermocouples, respectively, into contact with a standard surface whose surface roughness and/or surface temperature has been known and by causing the data collecting thermocouples to perform a relative movement with respect to the standard surface under the same contact condition and the same relative movement conditions as those of the first and second measuring thermocouples with respect to the surface to be measured.