ASTM_E_2387_-_05_2011.pdf

Designation:E238705(Reapproved 2011)Standard Practice forGoniometric Optical Scatter Measurements1This standard is issued under the fixed designation E2387;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice describes procedures for determining theamount and angular distribution of optical scatter from asurface.In particular it focuses on measurement of the bidi-rectional scattering distribution function(BSDF).BSDF is aconvenient and well accepted means of expressing opticalscatter levels for many purposes.It is often referred to as thebidirectional reflectance distribution function(BRDF)whenconsidering reflective scatter or the bidirectional transmittancedistribution function(BTDF)when considering transmissivescatter.1.2 The BSDF is a fundamental description of the appear-ance of a sample,and many other appearance attributes(suchas gloss,haze,and color)can be represented in terms ofintegrals of the BSDF over specific geometric and spectralconditions.1.3 This practice also presents alternative ways of present-ing angle-resolved optical scatter results,including directionalreflectance factor,directional transmittance factor,and differ-ential scattering function.1.4 This practice applies to BSDF measurements on opaque,translucent,or transparent samples.1.5 The wavelengths for which this practice applies includethe ultraviolet,visible,and infrared regions.Difficulty inobtaining appropriate sources,detectors,and low scatter opticscomplicates its practical application at wavelengths less thanabout 0.2 m(200 nm).Diffraction effects start to becomeimportant for wavelengths greater than 15 m(15 000 nm),which complicate its practical application at longer wave-lengths.Measurements pertaining to visual appearance arerestricted to the visible wavelength region.1.6 This practice does not apply to materials exhibitingsignificant fluorescence.1.7 This practice applies to flat or curved samples ofarbitrary shape.However,only a flat sample is addressed in thediscussion and examples.It is the users responsibility to definean appropriate sample coordinate system to specify the mea-surement location on the sample surface and appropriate beamproperties for samples that are not flat.1.8 This practice does not provide a method for ascribingthe measured BSDF to any scattering mechanism or source.1.9 This practice does not provide a method to extrapolatedata from one wavelength,scattering geometry,samplelocation,or polarization to any other wavelength,scatteringgeometry,sample location,or polarization.The user must makemeasurements at the wavelengths,scattering geometries,sample locations,and polarizations that are of interest to his orher application.1.10 Any parameter can be varied in a measurement se-quence.Parameters that remain constant during a measurementsequence are reported as either header information in thetabulated data set or in an associated document.1.11 The apparatus and measurement procedure are generic,so that specific instruments are neither excluded nor implied inthe use of this practice.1.12 For measurements performed for the semiconductorindustry,the operator should consult Practice SEMI ME 1392.1.13 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E284 Terminology of AppearanceE308 Practice for Computing the Colors of Objects by Usingthe CIE SystemE1331 Test Method for Reflectance Factor and Color bySpectrophotometry Using Hemispherical Geometry1This practice is under the jurisdiction of ASTM Committee E12 on Color andAppearance and is the direct responsibility of Subcommittee E12.03 on Geometry.Current edition approved July 1,2011.Published July 2011.Originally approvedin 2005.Last previous edition approved in 2005 as E2387 05.DOI:10.1520/E2387-05R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 2.2 ISO Standard:ISO 13696 Optics and Optical InstrumentsTest Methodsfor Radiation Scattered by Optical Components32.3 Semiconductor Equipment and Materials International(SEMI)Standard:ME 1392 Practice for Angle Resolved Optical Scatter Mea-surements on Specular and Diffuse Surfaces43.Terminology3.1 Definitions:3.1.1 Definitions of terms not included here will be found inTerminology E284.3.2 Defin