STRAIGHTNESS MEASURING DEVICE AND STRAIGHTNESS MEASURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a straightness measuring device and a straightness measuring method capable of accurately measuring straightness of a movement locus of a coating nozzle even when a substrate increases in size.SOLUTION: A straightness measurement device comprises a laser spectroscopic interferometer 14 and a mirror M. The mirror M is arranged at a position opposing to the laser spectroscopic interferometer 14 arranged on a coating head 20, in a state a reflection surface of the mirror M is parallel to a main scan direction guide section 31. The surface of the mirror M has high flatness. At this time, a distance between the reflection surface of the mirror M and the laser spectroscopic interferometer 14 is 1 mm or less. The mirror M is arranged on the entire area of application of a coating liquid by nozzles 23 associated with the movement of the coating head 20 in a main scan direction.