JPS6488337A - Hardness meter - Google Patents

Abstract

PURPOSE:To exactly measure the shape of the surface of a sample before and after forming an indentation and to improve the hardness measuring accuracy by measuring the indentation after the indenter is pushed in, by an optical non-contact surface shape measuring instrument. CONSTITUTION:An optical non-contact surface shape measuring instrument 2 uses a laser diode 12 as a light source and radiates measuring light to a sample 10 being in a measuring position through a collimator lens 13, a polarization beam splitter 14, a 1/4 wavelength plate 15 and an objective lens 16. Also, a reflected light from the surface of the sample goes to a parallel luminous flux from the lens 16, passes through the splitter 14 and the wavelength plate 15 and made incident on a beam splitter 18. Subsequently, reflected light beams from the surface of the sample, which transmits through and reflected from the splitter 18 pass through critical angle prisms 19, 20 and made incident on photodiodes 21, 22 and 23, 24, respectively. In such a state, by bringing differential outputs of the diodes 21, 22 and 23, 24 to arithmetic processing, its shift is discriminated, based on a sample focal position to be measured, as a reference. In such a way, a hardness value of the sample 10 can be measured exactly.