METHOD AND DEVICE FOR MEASURING INSIDE DIAMETER OF HOLLOW TRANSPARENT BODY

PROBLEM TO BE SOLVED: To provide a method and a device for measuring inside diameter of hollow transparent body capable of measuring the inside irregularities or curve of a glass bead. SOLUTION: This method for measuring the inside shape of a glass bead a that is a hollow transparent body comprises putting a plug to the opening part of the glass bead a to seal the cavity in the glass bead a; dipping the sealed glass bead a in a liquid 1 having the same refractive index as that of the glass bead a; irradiating the glass bead a with laser beam in this state; receiving the transmitted light by a optical sensor 44 divided in two; and detecting the inside ridge of the glass bead a from the light receiving quantity of each optical sensor 44a and 44b. The glass bead a is scanned in the axial direction (the vertical direction to the surface of Fig. 1) to measure the inside irregularities or curve of the through-hole b.