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EL Light Output Definition.Pdf GWENT GROUP ADVANCED MATERIAL SYSTEMS Luminance The candela per square metre (cd/m²) is the SI unit of luminance; nit is a non-SI name also used for this unit. It is often used to quote the brightness of computer displays, which typically have luminance’s of 50 to 300 nits (the sRGB spec for monitor’s targets 80 nits). Modern flat-panel (LCD and plasma) displays often exceed 300 cd/m² or 300 nits. The term is believed to come from the Latin "nitere" = to shine. Candela per square metre 1 Kilocandela per square metre 10-3 Candela per square centimetre 10-4 Candela per square foot 0,09 Foot-lambert 0,29 Lambert 3,14×10-4 Nit 1 Stilb 10-4 Luminance is a photometric measure of the density of luminous intensity in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. The SI unit for luminance is candela per square metre (cd/m2). The CGS unit of luminance is the stilb, which is equal to one candela per square centimetre or 10 kcd/m2 Illuminance The lux (symbol: lx) is the SI unit of illuminance and luminous emittance. It is used in photometry as a measure of the intensity of light, with wavelengths weighted according to the luminosity function, a standardized model of human brightness perception. In English, "lux" is used in both singular and plural. Microlux 1000000 Millilux 1000 Lux 1 Kilolux 10-3 Lumen per square metre 1 Lumen per square centimetre 10-4 Foot-candle 0,09 Phot 10-4 Nox 1000 In photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of the intensity of the incident light, wavelength-weighted by the luminosity function to correlate with human Gwent Electronic Materials Ltd. Telephone:- +44 (0) 1495 750505 Monmouth House, Applied Enzyme Technology Ltd. Telefax :- +44 (0) 870 052 8250 Mamhilad Park, Gwent Biotechnology Systems Ltd. E-Mail :- [email protected] Pontypool, Gwent Sensors ltd. Web Site :- http;//www.gwent.org Torfaen, LRH Ltd. NP4 0HZ United Kingdom Page 1 of 2 brightness perception. Similarly, luminous emittance is the luminous flux per unit area emitted from a surface. Luminous emittance is also known as luminous exitance. Luminous energy In photometry, luminous energy is the perceived energy of light. This is sometimes also called the quantity of light. Talbot 3600 Lumen second 3600 Lumen minute 60 Lumen hour 1 Luminous energy is not the same as the radiant energy, the corresponding objective physical quantity. This is because the human eye can only see light in the visible spectrum and has different sensitivities to light of different wavelengths within the spectrum. When adapted for bright conditions (photopic vision), the eye is most sensitive to light at a wavelength of 555 nm. Light with the same power at longer or shorter wavelengths has a lower luminous energy Luminous flux Lumen 1 Candela steradian 1 Lux square metre 1 In photometry, luminous flux or luminous power is the measure of the perceived power of light. It differs from radiant flux, the measure of the total power of light emitted, in that luminous flux is adjusted to reflect the varying sensitivity of the human eye to different wavelengths of light Luminous intensity Candela 1 Lumen per steradian 1 Hefnerkerze 1,11 Candlepower 1,02 In photometry, luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye. The SI unit of luminous intensity is the candela (cd), an SI base unit. Page 2 of 2 .
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