Dmg Mori Company Limited

Dmg Mori Seiki Co., Ltd.

Yusuke Nakamura

Hideaki Tamiya

Kenji Matsushita

Yasuhito Nomoto

Yoshiyuki Mitera

Shun Katoh

Yoshiyuki Midera

A displacement detection apparatus can reduce a measurement error even when a diffraction grating is displaced and/or tilted to a direction other than the measurement direction. A displacement detection apparatus includes a light source which emits light, a luminous flux-splitting section, a diffraction grating, a diffracted light-reflecting section, a correcting lens, a luminous flux-coupling section, and a light-receiving section. The diffracted light-reflecting section reflects a first luminous flux and a second luminous flux so as to be perpendicular to one of measuring planes of the diffraction grating and be parallel to each other. The correcting lens is arranged between the diffracted light-reflecting section and the diffraction grating.

Displacement detection apparatus

A first light flux serving as object light is caused to enter a member to be measured, and reflected light thereof is caused to enter again the member to be measured after being diffracted by a first diffraction grating. Then, the second-time reflected light of the first light flux by the member to be measured is diffracted by a second diffraction grating. By diffracting the first light flux by the second diffraction grating, a change of the optical path length caused by tilting of the member to be measured is cancelled.

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Isehara, Japan

Yusuke Nakamura