Something about the measurement way of LED brightness

As with traditional light source, led street lights wholesale source, optical unit of measure is unified.In order to make readers to understand and easy to use, the following will briefly introduce the relevant knowledge:A flux,Light flux is refers to the amount of light emitted at a light source in a unit time, the radiation power by the human eye can feel that part of the radiation energy.It is a band of radiation energy per unit time and the product of the relative rate of visibility of the band.Due to the human eye to different wavelengths of light relative rate of view is different, so different wavelength of light radiation power is equal, the luminous flux is not equal.The symbol for Φ of luminous flux, unit for lumens (Lm).According to the spectral radiant flux Φ (lambda), thus can get flux formula:GV Φ = Km s Φ (lambda) (lambda) d lambdaFormulas of V (lambda) - relative spectral luminous efficiency;Km - radiation spectral luminous efficiency of the maximum value, the unit for Lm/W.In 1977 by the international metrology committee to determine the Km value is 683 lm/W (lambda m = 555 nm).Second, the light intensityLight intensity refers to the unit time per unit area by light energy, and energy is proportional to the frequency, is the sum of their intensity (integral), can also be understood as the luminous intensity of light source in a given direction I was the solid Angle of the light source in the direction of the luminous flux transfer within d Φ divided by the quotient of the solid Angle yuan d ΩThe unit of luminous intensity is candela (CD), 1 CD = 1 lm/sr.The space of all directions of light intensity is the sum of luminous flux.Third, brightnessWe've been testing the brightness of the led street lights wholesale and LED optical radiation safety in the process of evaluation, commonly used imaging method, tests on the chip microscopic imaging may be used for measurement.Brightness is the brightness of the light source on the face of a certain place, L is the binning dS luminous intensity in a given direction is divided by the area element in the plane perpendicular to a given direction orthogonal projection area of the businessBrightness of the unit is the candela per square meter (CD/m2).When light emitting surface and measuring direction is vertical, cosine theta = 1.Four, lightLight intensity of illumination is refers to the object, illuminated with acceptable flux per unit area.Light and lighting source, be according to the surface and the position of the light source in the space, size and the intensity of light source and light is directly proportional to the Angle of incidence of yu xuan, and with the light source to be as is inversely proportional to the square of the distance of the object surface.Point on the surface of illuminance E is incident luminous flux on contains bin point d Φ divided by the quotient of the bin area of dS.Unit for lux (LX), 1 LX = 1 lm/m2.

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