Transmittance usage and principle analysis

1. What is transmittance?

Transmittance is an important parameter for evaluating a material's ability to transmit light. Simply put, it describes how much energy is retained after light passes through the material. When light shines on the surface of a material, it undergoes three different fates: some are reflected back, forming the common reflection we see; Part of it is absorbed internally by the material and converted into heat energy; Only the remaining part can successfully penetrate the material and become transmitted light.

The calculation method of transmittance is intuitive and clear: the ratio of transmitted light flux to incident light flux, multiplied by 100%, is converted into a percentage representation. A glass with a transmittance of 90% means it allows 90% of the incident light to pass through, with only 10% of the light being reflected or absorbed.

2. Actual usage scenarios of transmittance

In the automotive manufacturing industry, the transmittance of the windshield is directly related to driving safety. Too high will produce excessive glare, while too low will affect the night driving vision. According to Chinese standards, the light transmittance of car windshields must not be less than 70%.

In the display industry, the transmittance of mobile phone and TV screens affects the brightness and color reproduction of the display. Higher transmittance means that brighter images can be obtained at the same backlight intensity, or lower power consumption can be achieved at the same brightness.

In the packaging industry, the light transmittance of beverage bottles and cling film is not only related to the product display effect, but also closely related to the shelf life of the contents. Many food and drug packaging require low light transmittance to prevent spoilage caused by light exposure.

In the construction industry, the transmittance of glass curtain walls affects indoor lighting efficiency and air conditioning energy consumption, and a balance needs to be found between high transmittance (increasing natural light) and low transmittance (reducing heat accumulation).

Transmittance has different effects on imaging systems/energy transfer systems/and spectral analysis in the optical industry.

3. Core principle of transmittance measurement

Understanding the principle of transmittance measurement requires starting with the interaction between light and materials. When a beam of light hits the surface of a material, it immediately splits into three paths: reflected light bounces back from the surface, forming a mirror image; Absorbing light is' swallowed 'by materials and converted into other forms of energy; Transmitting light successfully passes through the material and continues its journey.

The true measurement of transmittance requires precise capture of the last part - transmitted light.