Luxmetern

Luxmetern is a term used to describe an instrument designed to measure illuminance, the amount of light incident on a surface, expressed in lux. In practice, Luxmetern devices are handheld or benchtop photometers that convert incident light into an electrical signal and display a numerical lux value. They are used in architecture, photography, horticulture, workplace safety, and quality control to assess lighting levels according to design requirements or regulatory guidelines.

Most Luxmetern devices use a photodiode or photodiode array with a spectral response approximating the photopic luminous efficiency curve V(λ). An optical cosine corrector ensures measurements are proportional to the incident light independent of angle. The signal is processed by a microcontroller or analog-to-digital converter and displayed; many units offer auto-ranging, data logging, and connectivity options such as Bluetooth or USB.

Calibration and accuracy are central to Luxmetern operation. Calibration is performed against traceable light sources, and manufacturers provide calibration certificates. The reported accuracy depends on sensor spectral response, geometry, and the light source spectrum. Some meters include correction factors for different color temperatures or lamp types to improve accuracy for specific applications.

Applications include designing and evaluating indoor lighting for comfort and compliance, ensuring workplace illumination meets safety guidelines, and supporting photography, videography, and horticultural lighting planning. Limitations include sensitivity to spectral content, flicker, and measurement geometry. Proper use typically involves selecting the appropriate measurement range, allowing adequate integration time, and placing the sensor on the surface or area of interest to obtain representative readings.