G
PHYSICS
G01
MEASURING; TESTING
G01N
INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
21/00
Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
G01N21/17
Systems in which incident light is modified in accordance with the properties of the material investigated