Explanation of the conversion relationship between illuminometer brightness and illuminance units
1) When a light source illuminates an object, we can measure which is emitted by the light source (Luminance? D brightness) or which is reflected by the object (Illuminance? D illuminance).
(2) Illuminance depends on the reflection characteristics of the object. It is very similar to a photo, it only measures reflected light. Its universal unit is lux.
(3) However, an EL lamp is a light source: it should be expressed in units of brightness, namely fL (foot Lambert) or cd/m2, also known as "nits". Some engineers prefer to use fL, while international standards organizations commonly use nits. The formula for converting nits to fL is: 1nits × 0.2919=1fL; And 1fL × 3.426=1nits [Note; these factors are derived from pi (π) and m2/ft2 (0.0929).
(4) Obviously, using lux is an incorrect unit and cannot be converted from lux to other units.
Luminous flux
Luminous flux: refers to the rate of light energy emitted by a light source or the flow rate of light (Flowrate), which is the basic quantity indicating the luminous ability of the light source, and is measured in lumens. For example, a 100 watt (W) light bulb can produce 1750lm, while a 40W cold white fluorescent tube can produce 3150lm of luminous flux. According to the definition, 1lm is the luminous flux emitted by a uniform point light source with a luminous intensity (l) of 1cd within a solid angle of 1 spherical degree.
Luminous intensity
Luminous intensity (Candlepower): Luminous intensity, abbreviated as luminosity, refers to the luminous flux emitted from a solid angle of a light source (unit: sr), which is the density distribution of the luminous flux emitted by the light source or lighting fixture in a selected direction in space, in candlelight (cd). A light source with a luminous intensity of 1cd can emit a luminous flux of 12.57lm. Luminance: The density of the luminous flux received on the illuminated plane, measured by the luminous flux per unit area. A light flux of 1lm is evenly distributed on a surface of 1 square meter (m2), resulting in an illuminance of 1 lux (environmental technology>illuminometer); A light flux of 1lm falls on a surface of 1 square foot (ft2), and its illumination value is 1 footcandle (fc).
