What is Light Transmissivity?


Light transmissivity is the term used to describe the extent to which light can pass through various materials, including glass. Typically quantified as a percentage, it represents the amount of light that can successfully traverse the tested materials.

Internal and external are the two primary categories under which light transmission is classified.

1. Internal Transmission:

Internal light transmission tests are commonly employed to assess a glass’s capacity to allow light to pass through, offering insights into various properties of the glass. These tests aid researchers in identifying potential material issues, enabling them to devise effective solutions.

2. External Transmission:

This form of light transmission is determined by evaluating the intensity of light entering the glass rather than the intensity of light as it exits. By considering these factors, an accurate representation of the actual light passage through a material can be derived, beyond the percentage provided by internal light transmission tests.

What Does Light Transmittance Mean?

Light transmittance refers to the quantity of light capable of passing through the surface of a material. Conversely, light transmittance indicates the degree of light energy absorption, reflection, and scattering by glass or other materials. Essentially, transmittance enables the precise calculation of light dispersion and a material’s capacity to obstruct photons.

What’s the Difference Between Transmittance and Transmissivity?

Transmittance denotes the ratio of light under normal incidence, while transmissivity represents the total light passing through the glass.

Radiance glazing parameters necessitate transmissivity, yet glazing manufacturers frequently provide transmittance values.

How are they Applied in the Real World?

Both light transmission and transmittance find extensive practical applications:

  • Assessing the efficiency of glass and window tints in vehicles, commercial establishments, and residential buildings.
  • Evaluating glass clarity in the aviation and aerospace sectors.
  • Testing the chemical, mechanical, and thermal attributes of glass for optical engineering designs.

While light transmission and transmittance exhibit subtle distinctions, their combined use proves valuable in determining diverse glass properties. This integrated approach significantly aids in evaluating the quality and transparency of materials required across various industries.

Must Read: What is Light Trapping?

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