DISPLACEMENT MEASUREMENT DEVICE

To provide a displacement measurement device which can measure the angular displacement and the shaft displacement.SOLUTION: A mirror 3 having a reflection part that is narrowed in the spot shape is provided on a measurement target 2, and a one-dimensional grating 3a is arranged so as to be superimposed on the mirror 3. Measurement light 101 having a wider irradiation range than the reflection part is irradiated on the mirror 3 so that the reflection part is included in the irradiation range, the 0-order reflection light 110 is divided into a first light flux 110a and a second light flux 110b, the first light flux 110a is received by a first sensor 41, the second light flux 110b is received by a second sensor 51, and the 1-order reflection light 111 is received by a third sensor 61. The angular displacements θx and θy around the X-axis and the Y-axis are detected on the basis of the signal output by the first sensor 41. The shaft displacements δx and δy in the X-axis and Y-axis directions are detected on the basis of the signal output by the second sensor 51. The angular displacement θz around the Z-axis is detected on the basis of the signal output by the third sensor 61.SELECTED DRAWING: Figure 1 【課題】角度変位とともに軸変位をも計測することが可能な変位計測装置を提供する。【解決手段】スポット状に絞られた反射部を有するミラー３を測定対象２に設け、そのミラー３に１次元回折格子３ａを重ねて配置する。ミラー３に対して反射部よりも広い照射範囲を有する測定光１０１を反射部が照射範囲に含まれるようにして照射し、０次反射光１１０を第１光束１１０ａと第２光束１１０ｂとに分光し、第１光束１１０ａを第１センサ４１で、第２光束１１０ｂを第２センサ５１で受光するとともに、１次反射光１１１を第３センサ６１で受光する。第１センサ４１が出力する信号に基づいてＸ軸及びＹ軸のそれぞれの軸周りの角度変位θｘ、θｙを検出し、第２センサ５１が出力する信号に基づいＸ軸及びＹ軸方向における軸変位δｘ、δｙを検出し、第３センサ６１が出力する信号に基づいてＺ軸の周りの角度変位θｚを検出する。【選択図】図１