REMOTE COLOR MEASURING APPARATUS

摘要

PURPOSE:To eliminate measuring errors due to re-reflection by arranging the diffraction surface of a diffraction grating in a specified direction to incident reflected light to keep reflected light from a light detecting element from being incident into a photo detector again. CONSTITUTION:The diffraction surface of a diffraction grating 26 is arranged inclined in the non-spectroscopic direction by an angle alpha according to the position and size of a light detecting element 30 from the normal of the plane X containing incident reflected light to prevent reflected light from the light detecting element 30 from being incident on the detecting element 30 again. Light focused from the surface of an object makes a parallel light with a collimator lens 24 and is incident on the diffraction grating 26. The incident light is directly reflected in the non-spectroscopic direction and focused with a concave mirror 28 to be incident into the light detecting element 30. A part of light is reflected with the element 30, focused with a concave mirror and reflected with the diffraction grating 26 again. As the diffraction grating is inclined by alpha in the non- spectroscopic direction, light is focused at the position P separated by DELTAL from the element 30 through the concave mirror 28.