ASTM_E_1392_-_96.pdf

Designation:E 1392 96Standard Practice forAngle Resolved Optical Scatter Measurements on Specularor Diffuse Surfaces1This standard is issued under the fixed designation E 1392;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(e)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 This practice explains a procedure for the determinationof the amount and angular distribution of optical scatter froman opaque surface.In particular it focuses on measurement ofthe bidirectional reflectance distribution function(BRDF).BRDF is a convenient and well accepted means of expressingoptical scatter levels for many purposes(1,2).2Additional datapresentation formats described in Appendix X1 have advan-tages for certain applications.Surface parameters can becalculated from optical scatter data when assumptions aremade about model relationships.Some of these extrapolatedparameters are described in Appendix X2.1.2 Optical scatter from an opaque surface results fromsurface topography,surface contamination,and subsurfaceeffects.It is the users responsibility to be certain that measuredscatter levels are ascribed to the correct mechanism.Scatterfrom small amounts of contamination can easily dominate thescatter from a smooth surface.Likewise,subsurface effectsmay play a more important scatter role than typically realizedwhen surfaces are superpolished.1.3 This practice does not provide a method to extrapolatedata for one wavelength from data for any other wavelength.Data taken at particular incident and scatter directions are notextrapolated to other directions.In other words,no wavelengthor angle scaling is to be inferred from this practice.Normallythe user must make measurements at the wavelengths andangles of interest.1.4 This practice applies only to BRDF measurements onopaque samples.It does not apply to scatter from translucent ortransparent materials.There are subtle complications whichaffect measurement of translucent or transparent materials thatare best addressed in separate standards(see Practice E 167and Guide E 179).1.5 The wavelengths for which this practice applies includethe ultraviolet,visible,and infrared regions.Difficulty inobtaining appropriate sources,detectors,and low scatter opticscomplicate its practical application at wavelengths less thanabout 0.25 m.Diffraction effects that start to become impor-tant for wavelengths greater than 15 m complicate its practicalapplication at longer wavelengths.Diffraction effects can beproperly dealt with in scatter measurements(3),but they arenot discussed in this practice.1.6 Any experimental parameter is a possible variable.Parameters that remain constant during a measurement se-quence are reported as header information for the tabular dataset.Appendix X3 gives a recommended reporting format that isadaptable to varying any of the sample or system parameters.1.7 This practice applies to flat or curved samples ofarbitrary shape.However,only a flat,circular sample isaddressed in the discussion and examples.It is the usersresponsibility to define an appropriate sample coordinatesystem to specify the measurement location on the samplesurface for samples that are not flat.1.8 The apparatus and measurement procedure are generic,so that specific instruments are neither excluded nor implied inthe use of this practice.1.9 This standard does not purport to address the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2.Referenced Documents2.1 ASTM Standards:E 167 Practice for Goniophotometry of Objects and Mate-rials3E 179 Guide for Selection of Geometric Conditions forMeasurement of Reflection and Transmission Properties ofMaterials3E 284 Terminology Relating to Appearance3F 1048 Test Method for Measuring the Effective SurfaceRoughness of Optical Components by Total IntegratedScattering42.2ANSI Standard:1This practice is under the jurisdiction of ASTM Committee F01 on Electronicsand is the direct responsibility of Subcommittee F01.06 on Silicon Materials andProcess Control.Current edition approved Dec.10,1996.Published December 1997.Originallypublished as E 1392-90.Last previous edition E 1392 90.2The boldface numbers in parentheses refer to a list of references at the end ofthe text.3Annual Book of ASTM Standards,Vol 06.01.4Annual Book of ASTM Standards,Vol 10.05.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.ANSI/ASME B46.1,Surface Texture(Surface Roughness,Waviness,and Lay)53.Terminology3.1 Definitions:3.1.1 Definitions of terms not included here will be found inTerminolo