| 摘要 |
PROBLEM TO BE SOLVED: To provide a lightwave interference measuring apparatus having a simple constitution, capable of measuring absolute distances at a high speed. SOLUTION: The lightwave interference measuring apparatus includes a wavelength-variable laser for performing periodical wavelength scanning between a first reference wavelengthλ<SB>1</SB>and a second reference wavelengthλ<SB>2</SB>for emitting a light beam; a wavelength-fixed laser for emitting a light beam having a third reference wavelengthλ<SB>3;</SB>a light-beam splitting element for splitting the light beams emitted by the wavelength-variable laser and the wavelength-fixed laser into a light beam to be tested and a light beam under test; a reference surface for reflecting the reference light beam; a surface under test for reflecting the light beam under test, a phase detection part for detecting a phase on the basis of interference signals between the reference light beam and the light beam under test; and an analyzer for sequentially determining the interference order of the third reference wavelengthλ<SB>3</SB>, on the basis of the third reference wavelengthλ<SB>3</SB>, a first synthetic wavelengthΛ<SB>12</SB>, a second synthetic wavelengthΛ<SB>13</SB>, an integer component of a phase change amount in the wavelength scanning, and interference orders of the first synthetic wavelength, and the second synthetic wavelength to calculate an absolute distance between the surface under test and the reference surface. COPYRIGHT: (C)2011,JPO&INPIT |
