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Illuminance Ev
Illuminance Ev is defined as the areal light flux density on a lighted area hit by the luminous flux Fv. Illuminance is measured in lux (lx=lm/m2), where luminous flux and area are put in as [lm] and [m2], respectively. Based on the illuminance Ev, a specific lighting solution can be calculated and designed.
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Luminance Lv
Luminance is defined as the areal density of luminous intensity of a light emitting or reflecting area which radiates the luminous intensity Iv at a given angle. Luminance Lv is measured in [cd/m2].
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Luminous intensity Iv
Luminous intensity Iv [cd] is among the key parameters describing an LED or LED display. It is defined as the luminous flux emanating from a point source within a solid angle W (steradian) into a particular direction. Hence, luminous intensity is the directional luminous flux Fv within a solid angle W. Today’s LEDs achieve a luminous intensity of Iv=10 cd or more. As intensity depends on the radiation angle, an LED chip equipped with a 30° reflector achieves a higher luminous intensity than an identical LED chip with a 60° reflector. That is, using a 60° reflector the same luminous flux Fv has to illuminate a larger area than using a 30° reflector.
In addition to these parameters, VS Optolelectronic’s in-house photometric laboratory is equipped to analyse all photometric, colorimetric and radiometric characteristics. Two in-house Gonio spectrum radiometers exactly determine the radiation characteristics of LEDs and LED light modules of up to 350 mm ř.
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