Radiance and irradiance are measurement units used within the field of radiometry. This blog post will outline the method behind these measurement units and highlight how Admesy spectroradiometers can be used to perform them.
Radiance is the unit that conveys the amount of radiant flux emitted, transmitted, or reflected by a surface. The radiance unit is determined as the unit power per solid angle per unit projected area.
Radiance provides an insight into how bright an object is, and it can sometimes be referred to as brightness, which isn’t necessarily correct. A spectral radiance measurement expresses radiance as a function of wavelength or frequency.
In contrast to radiance measurements, irradiance is the radiant flux received by a surface or the flux that is incident on the surface. The irradiance unit is determined as power per unit area.
There is a clear relationship between irradiance and distance. As the distance between the radiation source increases, the irradiance decreases. This is an important and useful aspect of this measurement unit when large areas require lighting, such as a football stadium.
Using Admesy Instruments for Radiance and Irradiance Measurements
Both radiance and irradiance measurements can be carried out using a spectroradiometer. Radiance measurements are conducted using a lens system as optics to target at diffuse surfaces such as display panels or OLEDs.
Irradiance measurements are often performed using a spectroradiometer combined with a cosine corrector with a predefined diffuse measurement surface or integrating sphere calibrated for irradiance.
Admesy provides a range of solutions to perform accurate radiance and irradiance measurements for a variety of display and lighting applications.
Our Rhea series spectrometer is a versatile device that adheres to the configurable spectral measurement demands within the range of 200 and 1100 nm. These spectrometers are customizable with various slit sizes, gratings, and wavelength ranges for specific measurement applications.
The Hera series spectrometer is extremely accurate and has excellent linearity in a robust housing. It covers various spectral ranges; 380 – 780 nm, 360 – 830 nm, and 200 – 1100 nm, and it is available in lens or cosine corrector configurations for radiance and irradiance measurements.
The Cronus series is the first spectro-colorimeter that combines a tri-stimulus colorimeter with a VIS spectrophotometer. This instrument provides accurate results, fast, making it suitable for lighting and display applications that require radiance and irradiance measurements.