An integrated sphere is indeed a common tool used for measuring various parameters of LED chips, including luminous flux (in lumens), color temperature (CCT – correlated color temperature), and color rendering index (CRI). Here’s a brief overview of how it works:
Luminous Flux (Lumen): The integrated sphere collects all the light emitted by the LED chip in all directions and then measures the total flux. This measurement gives an indication of the total light output of the LED chip.
Color Temperature (CCT): The color temperature of light emitted by the LED chip is determined by its spectral distribution. Inside the integrated sphere, the light is diffused and mixed thoroughly, so the color temperature can be accurately measured using a spectrometer or colorimeter.
Color Rendering Index (CRI): CRI measures how accurately a light source renders colors compared to a reference light source such as daylight. Inside the integrated sphere, the light from the LED chip illuminates a standard set of color patches, and the reflected light is measured. The CRI value is calculated based on the difference between the colors as rendered by the LED light and the reference light.
