2002 年 68 巻 7 号 p. 967-971
Equipment for measuring the shape of a groove with a depth of 3.6-4.5μm and a width of 0.15-0.30 mm inside a kinetic pressure bearing (K.P.B), which is used for magnetic discs, with a length of 8.75 mm and an inner diameter of 3 mm, is developed. The light projected to a specimen through a lens makes a small spot near the inside wall of the specimen. The position of the wall in the specimen is determined by detecting an image of the spot reflected on the wall. A two-dimensional theoretical analysis shows that the depth of the groove can be measured with an error of less than ±0.05μm. An experimental result shows that the depth of the groove can be measured with an amount of scatter less than -0.2 -+0.2 μm. As this scattering is sufficiently small to measure the depth of the groove, this equipment can be used in a production line.