Definition
A haze diastometer is a precision instrument used to measure the optical properties of transparent or translucent materials. It mainly evaluates the scattering effect of materials when light passes through, quantifying two key parameters: haze and light transmittance. Haze refers to the proportion of light that deviates from the direction of incidence due to scattering inside or on the surface of the material, showing a hazy or blurry appearance. Light transmittance characterizes the ability of a material to transmit light. The instrument plays an important role in materials science, industrial production, and quality control, and its measurement results are often calibrated and verified according to international standards such as ASTM D1003 and ISO 14782.
Principle
The haze diastometer is based on integrating sphere technology to achieve measurement. The light source inside the instrument emits a beam of parallel light, and after passing through the sample to be tested, part of the light is directly transmitted, and some of it changes direction due to scattering. As the core component, the integrating sphere collects all transmitted light and measures the total transmitted and scattered light flux separately through an internal detector. The haze value is obtained by calculating the ratio of scattered light flux to total transmitted light flux and is mathematically expressed as:
H = (Td / Tt) × 100%
where H represents haze, Tdis the scattered transmitted light flux, Ttis the total transmitted light flux. The light transmittance is calculated by the ratio of the transmitted light flux to the incident light flux of the sample.
Measurement method
The standard measurement process includes sample preparation, instrument calibration, data acquisition, and analysis of results. First, the sample is cut to size to ensure a clean and scratch-free surface. After the instrument is warmed up, calibration is carried out using a standard reference plate to eliminate ambient light and system errors. During measurement, the sample is placed at the entrance of the integrating sphere, and the instrument automatically records the transmission data. Modern haze translucence mirror meters are often integrated into digital systems, which support multiple measurements to take the average value and directly output the haze and light transmittance values. To ensure reliable results, the operation should be carried out in a controlled environment (e.g., constant temperature and humidity) to avoid external light interference.
Influencing factors
Measurement results are influenced by a variety of factors. Sample characteristics such as thickness, surface roughness, internal inhomogeneity, and color can alter light scattering behavior. Instrument factors include light source stability, integrating sphere coating reflectivity, and detector sensitivity, which require regular maintenance to ensure accuracy. Environmental conditions such as temperature fluctuations or airborne dust can also introduce biases. Operating specifications are equally critical, such as sample placement angle deviations or inadequate calibration can lead to system errors. Therefore, standardized operating procedures and instrument condition monitoring are the basis for obtaining reliable data.
Applications
Haze transilluminators are widely used in the evaluation of optical properties of non-medical materials. In the plastics industry, it is used to monitor the transparency and clarity of films, sheets, such as packaging materials and display components. The automotive industry uses it to test the visual performance of glass and plastic windows. In the field of coatings and coatings, surface smoothness and durability are evaluated by haze values. In addition, the instrument provides critical data support for product consistency control in optical component manufacturing, paper quality inspection, and food packaging compliance verification.
Selection considerations
When choosing a haze reflector, it is necessary to comprehensively consider the measurement needs and technical parameters. Instruments should comply with international standards such as ASTM or ISO to ensure data comparability. The measurement range should cover the haze vs. light transmission range of the intended sample, e.g. low-haze materials require a high-resolution detector. Automation features such as data storage and software analysis can improve efficiency. In addition, instrument stability, calibration convenience and after-sales service are also practical factors. Users can choose between basic and research configurations based on sample type, testing frequency, and budget.