试验的标准如下所示,求大侠指点下操作方法和原理.谢谢
4.5PhotometryTest
Thistestmeasurestheluminousintensitiesattestpointsthroughoutthelightdistributionpatternas
specifiedbytheapplicableSAEPublicationforthesampledevice.
4.5.1PHOTOMETRICTESTEQUIPMENT
4.5.1.1Thepositioner(goniometer)configurationshallbecapableofpositioningthesampledeviceat
thetestpointpositionspecifiedintheapplicableSAEPublication.Therecommended
goniometerconfigurationisspecifiedasTypeAasshowninFigureB1ofSAEJ1330.Other
systemsmaybeusedtoachieveequivalentpositioning,butitwillbenecessaryatcompound
anglesgreaterthan5degreesfrom“H-V”tocalculatethepositionwhichisequivalenttothatof
therecommendedgoniometer.
4.5.1.2Thephotometersystemshallconsistofasensor,amplifier,andindicatorinstrument.The
systemshallbecapableofprovidingtheluminousintensityreading(candela)oftheoutputof
thedevicebeingtested.
4.5.1.3Thesensor,unlessotherwisespecified,shallhaveamaximumeffectiveareathatwillfitwithin
acirclewhosediameterisequalto0.009timestheactualtestdistancefromthelightsourceof
thedevicetothesensor.Thesensoreffectiveareaistheactualareaofinterceptedlight
strikingthedetectorsurfaceofthephotometer.Forsystemswithlens(es)thatchangethe
diameteroftheintercepterlightbeambeforeitreachestheactualdetectorsurface,the
maximumsizerequirementsshallapplytothetotalareaoflightactuallyinterceptedbythelens
surface.Thesensorshallbecapableofinterceptingalldirectilluminationfromthelargest
illuminateddimensionofthesampledeviceatthetestdistance.
4.5.1.4Thecolorresponseofthephotometersensorshallbecorrectedtothatofthe1931CIE
Standardobserver(2degree)PhotopicResponseCurve(ASTME308).
4.5.2PHOTOMETRICTESTPROCEDURE
4.5.2.1TheDUTshallbemountedandtestedinthedesignposition(s)orasmountedonthevehiclein
accordancewiththemanufacturer’sinstruction.
4.5.2.2Unlessotherwisespecified,accurate,ratedbulbsshallbeused.Theyshallbeselectedfor
accuracyasspecifiedinSAEJ387andshallbeoperatedattheirdesignmeanspherical
candlepower.
4.5.2.3Wherespecialbulbsareused,theyshallbeagedinaccordancewithSAEJ387andoperated
attheirdesignmeansphericalcandlepower.
4.5.2.4Ifthedesignvalueofthemeansphericalcandlepowerisnotavailableorthelightsourceisan
integralpartofthedevice,operatethelightsource(bulbfilament)atitsspecifieddesign
voltage.
4.5.2.5Ifthedesignmeansphericalcandlepowerofthebulbisintentionallymodifiedfrom
specificationsforadevicethroughinternalorexternalcircuitry,operatethebulbwiththe
voltage-modificationcircuitryattachedandwiththespecifieddesignvoltageappliedtotheinput
ofthemodificationcircuitry.
4.5.2.6Thetestdistanceformeasuringtheluminousintensityshallbemadeatequalto,orgreater
than,theminimumtestdistancebetweenthecenterofthelightsource(orthefaceofareflex
reflector)andthephotometersensorasspecifiedintheSAEPublicationapplicabletothe
functionofthesampledevice.
4.5.2.7ThelocationsoftestpointsarespecifiedintheapplicableSAEPublication.Thefollowing
nomenclatureshallapply:
4.5.2.7.1Theletters“V”and“H”designatetheverticalandhorizontalplanesintersectingboththe
centerofthedevicelightsource(orcenterofareflexreflector)andthegoniometeraxis.
4.5.2.7.2Adeviceusingabulbthathasamajorandaminorlightsourceshallbeorientedwithrespect
toitsmajorlightsource.
4.5.2.7.3“H-V”designatesthezerotestpointangleattheintersectionofthe“H”and“V”planes.
Unlessotherwisespecified,thisintersectionshallbeparalleltothelongitudinalaxisofthe
vehicleinthecaseoffrontandrearfunctiondevicesandshallbehorizontaland
perpendiculartothelongitudinalaxisofthevehicleinthecaseofsidefunctiondevices.The
letters“U,”“D,”“L,”and“R”(up,down,left,andright,respectively)designatestheangular
positionindegreefromtheH-Vplanestothegoniometerasviewedfromalamportothe
sourceofilluminationasviewedfromareflexreflector.
4.5.2.7.4Thehorizontalangleofthetestpoint(“L”leftand“R”right)istheanglebetweenthevertical
planeandtheprojectionofthelightrayfromthedeviceontothehorizontalplane.
4.5.2.7.5Theverticalangleofthetestpoint(“U”upand“D”down)isthetrueanglebetweenthe
horizontalplaneandthelightrayfromthedevice.
4.5.2.7.6Thedirectionofanangulartestpointcanbevisualizedwhenanobserverstandsbehindthe
deviceandlooksinthedirectionoftheemanatinglightbeamtowardsthephotometersensor
whenthedeviceisproperlyaimedwithrespecttoH-V.
4.5.2.7.7Photometricmeasurementsshallbemadewiththelightsource(s)steadyburning.The
luminousintensitymeasurements,incandela,shallberecordedforeachofthetestpoints
andzonesspecifiedforthatfunctionofthedevicebeingtested.
