Patent attributes
A curvature measurement apparatus according to an embodiment includes: a laser beam emitting portion emitting a laser beam; a first polarization beam splitter separating the emitted laser beam into first and second laser beams in different polarization directions and in different travel directions; a mirror reflecting the first laser beam so that the first and second laser beams travel side by side to a substrate; a second polarization beam splitter transmitting the second laser beam mirror-reflected from the substrate and reflecting the first laser beam, mirror-reflected from the substrate, in a direction different from a travel direction of the second laser beam; a one-dimensional first position detection device detecting an incident position of the reflected first laser beam on the first position detection device; and a one-dimensional second position detection device detecting an incident position of the transmitted second laser beam on the second position detection device.
