| 摘要 |
PURPOSE:To enable measuring of a period of an object to be tested through the measurement of a distance between point spectra on a Fourier transformation surface, by a method wherein the object to be tested is formed through a regularly- arranged pattern. CONSTITUTION:A coherent light, emitted from a He-Ne laser source 1, is enlarged into a proper size by means of a colimator lens system 2, and the object 4 to be tested on a XY stage 3 is illuminated by said light. Thiis enbales the transmitted light to obtain a Fourier transformation pattern on a surface, which is away from by a focus distance f, through the aid of a lens 5. The image of the Fourier transformation pattern, which is represented in a gathering of luminescent spots. is picked up by means of a detector array 16, (for example, CCD image pick-up element), and a distance between the luminescent stops can be found from said electric signal. |
