| 摘要 |
PROBLEM TO BE SOLVED: To provide a displacement detector that can detect displacement in a height direction of a measurement object with high precision and can make rapid and stable measurement.SOLUTION: A measurement member 5 is irradiated with a first luminous flux L1 to be object light, and reflecting light of the flux is diffracted by a first diffraction grating 7 and is caused to enter the measurement member 5 again. Further, second reflecting light of the flux L1 from the measurement member 5 is diffracted by a second diffraction grating 9. Diffracting the flux L1 with the second diffraction grating 9 cancels change of length of light path made by tilting of the measurement member 5. |
