Regular and diffuse transmission

Linshang LS116 light transmittance meter is an instrument only suitable for detecting regular transmission. In the propagation of light in the medium, there are generally three transmission phenomena: regular transmission, diffuse transmission, and mixed transmission.

Regular transmission:
When light is irradiated on a transparent material, the transmitted light is directional transmission with strong directionality according to the law of geometric optics, that is, regular transmission.

Diffuse transmission:
When light passes through a transmission material with a rough surface (such as frosted glass), the transmitted light diffuses, and there is no regular transmission in the macroscopic view, which is called diffuse transmission.
If light is irradiated on a light-transmitting material with good diffusion (such as opal glass, etc.), the transmitted light will spread in all directions and be evenly distributed in the entire hemispherical space. At this time, when the brightness is the same in all directions, This is called isotropic diffuse transmission (previously called uniform diffuse transmission).

Mixed transmission:
When light is irradiated on the transmission material, the transmission performance is between regular transmission and diffuse transmission (or scattered transmission), which is called mixed transmission.

The above is the meaning of three kinds of transmission. Linshang LS116 light transmittance meter is only suitable for detecting the light transmittance of regular transmission materials, while the LS117 densitometer can be used to measure the light transmittance of diffuse transmission and mixed transmission materials.

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