Haze Measuring Principle

When light hits a transparent or translucent plastic sample, part of it produces directional reflection, and part of it produces diffuse reflection; after entering the sample, part of the light is absorbed and part is penetrated. In the light that irradiates the sample, the main penetrating part advances according to the law of refraction, and the rest produces hemispherical penetrating, and its advancing direction is scattered, which is called diffuse penetrating. In order to evaluate the optical properties of materials, it can be expressed by transmittance and haze. Among them, the transmittance value is the ratio of the luminous flux that penetrates the object to the luminous flux that hits the object; the haze is expressed as a percentage of the ratio of the scattered luminous flux that penetrates the sample and deviates from the direction of the incident light to the transmitted luminous flux. Generally, only the scattered light flux that deviates from the incident direction by more than 2.5° is used to calculate the haze value.

In the industry, an integrating sphere haze meter or a photoelectric haze meter is generally used to test the transmittance and haze of transparent or translucent materials. Calculate the total transmittance, diffuse transmittance and Haze.