| 摘要 |
<p>E780 CAN An electro-optical measuring system in a photogrammetric comparator or stereocompiler comprises a visible light transparent phase grating which is carried upon a surface of the photo support plate of the device. The grating is formed as a composite layer of .lambda./4 films of at least two dielectric materials of different refractive index which are deposited on the support in such a manner as to yield parallel bands in which the two film materials are in alternating sequence from band to band. As a result of this structure which ensures a constant physical and optical thickness with respect to transmitted imaging light over the whole grating pattern, image-degrading diffraction of the transmitted visible light is avoided, yet the grating pattern provides interfering diffraction in reflection which may be utilized in a precise displacement measuring system.</p> |
