(under the class definition) Subject matter wherein visible radiation is passed directly or with internal reflection through solid, liquid, or gaseous substances or any mixture thereof including coated solids, and detected visually or photoelectrically after it has passed through the substance
for the purpose of determining the intensity, the change of intensity, the extinction of the radiation, or the outline of the radiation source or image.
(1) Note. As between this Class 356 and Class 250, the claimed combination of a light source, a support for a substance to be tested by a transmission test, and a photosensitive detector with or without indicating structure is classified in this Class 356 providing there is the disclosure of an indicator responsive to the detector not provided for elsewhere. If an indicator of the quantitative type such as a meter is present in the claimed combination, classification is in Class 356 regardless of the claiming of the support.
(2) Note. The patents claiming a light source with the transmission of this light through a substance and detected (usually quantitatively) are in subclasses 432+. If no light source is claimed and only the light intensity of a specific location or locations is involved and not the amount of light attenuated in the passage of the light through a medium or a substance, or only the intensity or a light source is desired without regard to the attenuation of the light in its passage through a medium, see subclasses 213+ on photometry.
SEE OR SEARCH THIS CLASS, SUBCLASS:
213+, for photometers. See also (2) Note above.
402+, for colorimetry.
445+, for light reflection measuring and testing. SEE OR SEARCH CLASS
209, Classifying, Separating, and Assorting Solids,
588, for automatically assorting articles by light transmission inspection.
250, Radiant Energy, especially
218, and 219 for photocell systems with articles or material in the optical path. See also (1) Note above.
