Brightness measured by the illuminance meter and illuminance units converted
(1) When a light source shines on an object, we can measure which is emitted by the source (Lumvnance? D brightness) or which is reflected by the object (Illuminance? D illuminance).
(2) Illuminance depends on the reflective properties of the object. It is very similar to a photograph in that it measures only reflected light. Its common unit is lux.
(3) However, an EL lamp is a light source: it should be expressed in units of luminance, i.e. fL (feet Lambert) or cd/m2, also known as "nits". Some engineers prefer fL, while the International Standards Organisation uses nits. nits is converted to fL by the following formulae: 1nits x 0.2919 = 1fL; and 1fL x 3.426 = 1nits [Note; these factors are derived from pi(π) and m2/ft2 (0.0929).
(4) It is clear that the use of lux is an incorrect unit, nor can it be converted from lux to other units. 1 Lux = 1 lumenpersquaremeter= 0.0929 footcandle 1 footcandle= 1lumen persquarefoot =10.764 Lux1 foot Lambert= 3.426 candelas per squaremeter (nit) 1nit (candelas per square metre) = 0.2919 footLambert
Luminous Flux
Luminous flux (Luminousflux): that is, the rate of light energy radiated by a light source or the rate of flow of light (Flowarte), for the description of the ability of the light source to emit light the basic amount of light, the unit is lumen (Lumen). For example, a 100-watt (W) light bulb produces 1,750lm, while a 40W cool white fluorescent tube produces a luminous flux of 3,150lm. By definition, 1lm is the luminous flux emitted by a uniform point light source of luminous intensity (l) 1cd at a stereo angle of 1 spherical degree.
(illuminance meter) brightness and illuminance unit conversion relationship luminous flux: Symbol Φ, unit lumen Lm, the luminous body per second kind of light emitted by the sum of the amount of light, i.e., luminous flux luminous intensity: Symbol I, unit candelabra cd, the luminous body in a particular direction unit stereoscopic angle emitted by the luminous flux illuminance: Symbol E, unit lux Lm/m2, the luminous flux of light emitted in the illuminated object unit area of light flux Brightness: Symbol L, unit Nitro cd/m2, illustrates the luminous flux emitted by the luminous body in a specific direction unit stereo angle unit area Luminous efficacy: unit lumens per watt Lm/w, illustrates the ability of an electric light source to convert electrical energy into light to the luminous flux emitted divided by the power consumption to be expressed.
