亮度的計算

1、發(fā)光器件的測量,,NRC INMS PAR Measurement CourseWeb Instruments,光度學和輻射度學的基本概念,A 輻射能通量（輻射功率Ψ，單位：瓦 W）輻射能通量的譜密度,輻射能通量的譜密度：,視見函數(shù),定義：,,,當λ= 555 nm 時，V=1,實驗表明：,,,λ= 400 nm,a 光通量,光源發(fā)出的輻射能通量通過視見函數(shù)的權(quán)重因子折合成對人眼起作用的有效視覺強度稱為光通量。單位：流

2、明 lm,,,有：,,或者：,,,最大光功當量，,1 lumen = 1/683 W at 555 nm,From a quantum mechanic perspective of photon flow rate and photon energy (E) at 555 nm,This is what 1 lumen is equivalent to.,b 發(fā)光強度 和 B 輻射強度,點光源發(fā)光強度,,,,Radiometric I

3、ntensity is the radiometric flux density (watts) per steradian (W/sr),Photometric (luminous) intensity is the luminous flux density per steradian expressed in candellas.,,,,,,Exponential Intensity Source: profiles r

4、adiation patterns of LEDs, both wide and and narrow beam widths.,Where n is the radiation exponent,,,,,,c 亮度和 C 輻射亮度,亮度：,,輻射亮度：,,,,d 照度和 D 輻射照度,(光)照度定義：,，,單位：lux, lx,輻射照度定義：,單位：W/m2,watts per square meter,，,點光源的照度,,,，,,

5、,面光源的照度,,,,,注意： （a）通常情況下光強的概念與這里的輻射 照度的概念一致，單位是W/cm2 。（b）照度是接收的概念，發(fā)光強度 和亮度是發(fā)射的概念。,Some Typical Luminance And Radiance Levels,視見函數(shù),,,,,400,,,500,,,600,,,,700,,,800,0,,,,,,1,,,,,,1.8,,,,,,,,,,,,,,,,,,

6、,Wavelength, nm,Photopic Sensitivity,y,This curve shows the relative sensitivity of the eye. To convert to photometric units from radiometric, multiply by 683 Lumens Per Watt,Color: Tristimulus Values,,,Describe Eye’s R

7、esponse to ColorBased on Color Matching ExperimentsSmall Number of ObserversLines are Approximations,,,Spectral radiance Le(λ), the usual units are Watt/steradian/m2/nm,,PR-705,Radiance(watts/sr/m2)3802.846e-003

8、3821.285e-0023842.987e-0023863.336e-0023881.459e-0023901.739e-0023921.675e-0023944.251e-0033961.720e-0023982.580e-0024002.076e-0024025.027e-0034041.362e-0024063.447e-0024083.644e-0024105.342

9、e-0024128.716e-0024141.359e-0014161.861e-0014182.458e-0014203.686e-001,PhotometryObserver: 2 degreesLuminance(cd/m2)8.138e+004Luminance(fl) 2.375e+004Scotopic Y(cd/m2)9.670e+004Sco

10、topic Y(fl) 7.025e+004Pho. Transmit. (%)N/APho. Reflect. (%)N/APho. Opt. DensityN/APho. AbsorptanceN/AObserver: 10 degreesLuminance(cd/m2)9.088e+004Luminance(fl) 2.

11、652e+004Pho. Transmit. (%)N/APho. Reflect. (%)N/APho. Opt. DensityN/APho. AbsorptanceN/A,RadiometryRadiance(watts/sr/m2) 3.393e+002Photon Rad.(photons/sr/m2/sec) 8.782e+020Rad. Transmit. (%)

12、 N/ARad. Reflect (%) N/ARad. Opt. Density N/ARad. Absorptance N/A,ChromaticityObserver: 2 degreesX 9.101e+004Y 8.138e+00

13、4Z 1.832e+005CCT 91020MK -1 11.0u-v Dev -0.0153x 0.2559y 0.2289u 0.1956v 0.2623u' 0.1956v' 0.3935Observer: 10 degrees,Avantes 光纖光譜儀 一個光子的能量：E = hc/? （J） 其中h =

14、Planck’s constant (6.626 × 10-34 J?s)c = Speed of light (2.998×108 m?s-1)?= Wavelength (m)  一個焦耳的光子數(shù) the number of photons per joule is:?（in nm）×5.034×1015  1 mol = 6.02308×

15、;1023 (Number of Avogadro)1 µmol = 6.02308×1017,單位換算 1 [ µWatt/cm2 ] = 1 [ µJoule/s/cm2 ]= 0.01 [ Joule/s/m2 ] ＝0.01×?(nm)×5.034×1015/6.02308/1017 [μMol/(s?m2) ]=

16、?(nm)×0.0000835785 [μMol/(s?m2) ] The photon count distribution [µMol/(s?m2?nm)] shows the photon flux received per square meter. Other photon count units that can be calculated from this are:? [µ

17、;Mol/(s?nm)] photon flux received at diffuser surface? [µMol/( m2?nm)] photons received per square meter during one integration cycle? [µMol/nm] photons received at diffuser surface during one integration

18、 cycle Illuminance曲線[ lm/m2或lux ]=測量的Irradiance曲線 [µWatt/cm2 ] ×0.01×683×視見函數(shù)Photometry 文件的表中：Illuminance值＝Illuminance曲線下積分（380nm－780nm）