Light transmission measurement for solid body or fluid in tube involves light source, collimation lens, lens and mirror and lens focusing light on photocell

摘要

The light transmission measurement system has a light source (1) consisting of a LED. It is followed by a collimation lens (2) and a protective window (3). A parallel light beam (10l) passes through the solid body or fluid under test (4). A reflector unit may be moved longitudinally to alter the length of the light path (13). The reflector unit has a protective window (5) and a lens (6) focusing the light onto a flat mirror (7). Reflected light passes back through the lens and window and a return beam (10ll) passes through the solid body or fluid under test to the first window and a lens (8) focusing light on a photocell (9).