| 摘要 |
<p>The wavelength (μ) of light to be measured is determined in accordance with the formula μ = Ds/N from the number (N) of interference fringes having predetermined repeating waveforms that occur when the optical path length is changed by the quantity Ds by moving continuously a movable portion (7) of an interference spectrometer portion (1) of a wavelength measuring apparatus at a constant speed. A wave number counter (13) counts the number of specific points in each period of the interference fringes entirely from a predetermined measuring start point to a predetermined measuring finish point to obtain wave number data (Na). A reference pulse generation portion (21) generates reference pulses having a higher frequency than the repeating waveforms of the interference fringes. Detection portions (22a, 23a) detect the first number of the reference pulses existing in one period of the interference fringes, the second number of the reference pulses existing inside the period from the measuring start point till the first specific point of the interference fringes in succession to the measuring start point and the third number of the reference pulses existing inside the period from the final specific point of the interference fringes to the measuring finish point. A calculation portion (26) corrects the wave number data (Na) to wave number data (NA) inclusive of fraction values using the first, second and third numbers, and measures highly precisely the wavelength of light to be measured in accordance with the following equation: μ = Ds/NA.</p> |
