专题篇-LED测试技术

LED测试技术MeasurementtechnologyofLED OUTLINE IntroductionofphotometryfacilitiesMeasurementofLEDsMeasurementofSSLproductsColorrenderingofwhiteLEDlightsources OUTLINE IntroductionofphotometryfacilitiesMeasurementofLEDsMeasurementofSSLproductsColorrenderingofwhiteLEDlightsources Photometricbench 4mlongLuminousintensity cd oflampsIlluminancemetersLuminancemetersAveragedLEDintensity A B 25 Cambient 2 5mAbsoluteIntegratingSphere AbsoluteIntegratingSphereMethodRealizationofthelumenCalibrationoftotalluminousfluxoflampsandLEDsUncertainty0 5 k 2 AbsoluteIntegratingSphereMethod Realizationofthelumen 1 Spatialnonuniformityofthesphereresponse2 Spectralmismatchofthesystem3 Angulardependenceofthediffusereflectance4 Illuminancenon uniformityovertheaperture LEDspherescanner MeasuredSRDFofthe2 5mintegratingsphere NormalizedSpatialResponsivityDistributionFunction SRDF oftheintegratingsphere TraditionalMethodforTotalLuminousFluxMeasurementinIndustry Errorsoccurduetospectralmismatchofthephotometerhead StrictsubstitutionwouldneedmanytypesofstandardlampsCorrectionwouldneedspectrumofthelampsaswellasspectralresponsivityofspheresystem PrecisemeasurementneedsthespectralresponsivityofthephotometerheadexactlymatchedtotheV function However inrealcases RecentTrendforTotalLuminousFluxfluxmeasurement Useofaspectroradiometer Theoretically thereisnospectralmismatcherror Coloroflampscanbemeasuredatthesametime Colorcanbemeasuredasspatialaverage Forsuchaspheresystem standardlampsfortotalspectralradiantfluxarerequired Suchstandardsarenotcommonlyavailable TotalSpectralRadiantFluxScale Thespectralradiantintensityorspectralirradianceofatestlampismeasuredinmanydirections over4 usingagoniometerequippedwithaspectroradiometer calledgoniospectroradiometer or Principles W nm nm Gonio spectroradiometerForrealizationoftotalspectralradiantfluxscale 360nmto830nmUncertainty1 8 to1 k 2 Dataexample FELlamp Transferstandardlampsfortotalspectralradiantflux Externalreferenceflux Totalspectralradiantfluxofthetestlamp kcorr l correctionfactor Absolutescaleofradiantfluxisbasedonthelumen Alternatemethod AbsoluteIntegratingSphereMethodAppliedSpectrally SpectralStrayLightCorrectionforspectrometers Straylightiscorrectedby I identitymatrix SinglecolorLEDs Integratingsphereilluminatedby320nmUVlaser fluorescence straylight Aftercorrection fluorescence OUTLINE IntroductionofphotometryfacilitiesMeasurementofLEDsMeasurementofSSLproductsColorrenderingofwhiteLEDlightsources MeasurementofLED SSLProducts LEDmodules clusters SSLproducts Totalluminousflux lm Luminousefficacy lm W Luminousintensity CIEAveragedIntensity Chromaticity CCT Duv CRI AngularintensitydistributionLuminaireefficacy lm W Measurementquantities LEDchips packages LEDchips packages LEDmodules clusters SSLproducts StandardsformeasurementofLED SSLproducts CIE127 2007DoesnotaddressthermalissuesofhighpowerLEDs ANSIC78 377Chromaticity draft IESNALM 79PhotometricMeas draft IESNALM 80Lifetime draft Nostandardsyet AveragedLEDIntensity CIEPub 127 1997 CIEAveragedLEDIntensityILEDA ILEDBUsemechanicalaxisoftheLED TotalLuminousFluxMeasurement RecommendedforallLEDs AcceptableforLEDswithnobackwardemission CIEPub 127 2007 Self absorption MeasurethesignalwithastandardLED thenwithatestLED withonlytheauxiliaryLEDturnedon CorrectthesignalforTestLEDbymultiplyingy0 y1 SpectralMismatchErrors Photometerhead SpectralMeasurement ColormeasurementTotalluminousfluxmeasurementwithnoneedforspectralmismatchcorrection Totalluminousfluxcanbemeasuredwithaspectroradiometer Theoretically nospectralmismatcherror CIEPub 127 2007 PartialLEDFlux CIEPub 127 2007 SpectralMeasurement Partialfluxmode Double monochromatorsystemChromaticity x y u v CCT CRI whiteLEDs MeasurementFacilitiesforLEDs Variabletemperaturechamber 2 5mintegratingsphereforluminousflux Gonio spectroradiometer TemperatureDependenceofLEDs Temperature controlledstandardLEDs Correctionmaybeappliedusingforwardvoltage AbigissueinHighPowerLEDs LEDsinSSLproductsareoperatingatmuchhighertemperature lm Wdropsto1 2to1 3 LargegapbetweenpublishedLEDperformance lm W andSSLproductsperformance lm W Lm Wvaluesannouncedfordifferentconditions pulse DC AstandardforhighpowerLEDspecificationsunderrealisticconditions asusedinluminaires isurgentlyneeded MeasurementofhighpowerLEDs MeasurehighpowerLEDsatafullDCcurrentatthermalequilibrium Aheatsinkisneeded resultsvarydependingonsizeofheatsink ambienttemp andhowLEDismounted Useatemperature controlledheatsink Setheatsinktemperatureat50 C 60 C needtobestandardized Useametal corePCboardtomounttheLEDtotheheatsink DataExample OUTLINE IntroductionofphotometryfacilitiesMeasurementofLEDsMeasurementofSSLproductsColorrenderingofwhiteLEDlightsources Incandescent Fluorescent 15lm W 90lm W SolidState WhiteLEDs Potential200lm W SolidStateLighting DrivingForce EnergySaving Lightingconsumes22 ofelectricity8 oftotalenergy statisticsofUSA SolidStateLighting by202550 reductionofenergyconsumedbylighting10 reductioningreenhousegasemissionsCustomersavingsof 115billionannually U S Dep Energy SSLProductsarecomingout Nicheapplications Generallightingapplications U S Dept ofEnergy sinitiativeforSSL DOE sLab to Marketstrategy CommercializationsupportProductTestingStandardsdevelopmentLaboratoryaccreditationprogramLightingforTomorrowcompetition DOEEnergyStarprogramforSSLproducts SSLproductsforgeneralillumination residentialandcommercialapplications Designedtoensureenergyefficiency alsoquality relativetoexistingsourcesRequirementsforluminaireefficacy chromaticity andCRI Ra 75forindoorapplications Requiresmeasurementsbyaccreditedlaboratories isdevelopingNVLAP NationalVoluntaryLaboratoryAccreditationProgram programforSSLproducts 2nddraft4 9 2007 MeasurementofSSLproducts Luminairesaremeasuredforrelativeluminousintensitydistributionandtotalluminousflux normalizedbymeasuredlamptotalluminousfux e g per1000lm Absolutescalegivenbypublishedlamplumenvalues Traditionalluminairephotometry RelativePhotometry ThismethoddoesnotworkforSSLproducts Lampandfixturecannotbeseparated PublishedLEDluminousfluxvaluesarenotreliable SSLproducts mostlyinaformofluminaire Testmethodsforlampsandluminairescombinedareneeded StandardizationforSSLspecificationandmeasurement StandardsforSSLbeingdevelopedinUSAANSIC78 377SpecificationsfortheChromaticity CDC2 IESNALM 79ApprovedmethodforelectricandphotometricmeasurementofSSLproducts CDC2 IESNALM 80LifetestofSSLproductsInternationalstandardsbeingdevelopedCIETC1 69ColorRenditionofWhiteLightSources Table1 ANSIC78 377ASpecificationsfortheChromaticityofSSLproducts Draft ANSIC78 377Draft FlexibleColor IESNALM 79ApprovedMethodforElectricalandPhotometricMeasurementofSSLProducts Draft CoversSSLproductscompletewithelectronicsandheatsinks therefore notemperatureissues SSLproductoperatedat25 Cambient DoesnotcoverLEDmodules LEDpackages norindividualLEDs AddressesbothaspectsoflampphotometryandluminairephotometryTotalluminousflux lumen electricalinput luminousefficacy lm W Chromaticity CCT CRI 4 integrated Angularintensitydistribution Nospectralmismatchcorrectionneededforluminousflux Totalluminousfluxandcolorquantitiesmeasuredatthesametime Colorquantitiesmeasuredasspatially 4 averagedvalues Oneofthemethodsrecommended forsmallerSSLproducts Agoniphotometerisneededforlarge sizeSSLproducts IESNALM 79ApprovedMethodforElectricalandPhotometricMeasurementofSSLProducts Draft l MeasurementofSSLproducts MeasuringarefrigeratorLEDluminaire Totalluminousflux lm Totalspectralradiantflux 350nmto830nm Chromaticity CCT Duv CRI 4 averaged 25 Cambienttemp SSLproductsupto 30cmdiameterorlinear 1 5mlong IndividualLEDsalsomeasured ForSSLproducts Dataexample LEDdownlight MeasurementofSSLproducts Goniospectroradiometer IntroductionofphotometryfacilitiesMeasurementofLEDsMeasurementofSSLproductsColorrenderingofwhiteLEDlightsources OUTLINE LuminousEfficacyofasource lm W RadiantEfficiency LuminousEfficacyofRadiation lm W X LuminousEfficacyofaSource lm W Opticalpower W Electricalpower W Luminousflux lm Opticalpower W Luminousflux lm Electricalpower W ExternalQ E Theoreticalmaximumlm Wofagivensource Dependsonlyonspectralpowerdistribution SPD Daylight Lowpressuresodiumlamp WhiteLED 520lm W 400lm W 250lm W Theoreticalmaximum ColorRenderingvs EnergyEfficiency Excellentcolorrendering colorrendering Nocolorrendering ProblemsofCRI 1 3 LEDModelPeaksat 457 540 605nmCRIRa 80 Ref LED Thisspectrumhashigherlm W Goodscoresdonotguaranteegoodsat