Reference

Principle

Illuminance is measured in lux (lx), which represents the amount of luminous flux falling on a surface area of one square meter. The following values are typical illuminance levels found in everyday environments:

Night (starlight): 0.001 – 0.02 lx

Moonlight night: 0.02 – 0.3 lx

Cloudy indoor environment: 5 – 50 lx

Cloudy outdoor environment: 50 – 500 lx

Sunny indoor environment: 100 – 1,000 lx

Direct summer sunlight (afternoon): approximately 100,000 lx

Reading (recommended illumination): 50 – 60 lx

Home video / TV viewing: around 1,400 lx

To improve lighting efficiency in practical applications, reflectors can be used to redirect more luminous flux toward specific directions, thereby increasing the illuminance on the target surface.