ASTM_F_1595_-_00_2012.pdf

Designation:F159500(Reapproved 2012)Standard Practice forViewing Conditions for Visual Inspection of MembraneSwitches1This standard is issued under the fixed designation F1595;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 covers procedures for performing visualinspection of membrane switches.This includes visual inspec-tion of overlays and circuitry.1.2 This practice defines lighting parameters,distance fromeye to specimen,viewing angle,and the viewing time allowedfor a specific size specimen.1.3 This practice is only designed for visual inspection ofaesthetic qualities of membrane switches.It is not intended forcolor matching or gloss measurement.1.4 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.Terminology2.1 Definitions:2.1.1 aesthetic qualitiesthese relate to the cosmetic ap-pearance of the membrane switch and include such character-istics as printing quality,uniformity of finish,material attri-butes,and mechanical integrity.2.1.1.1 DiscussionThese are often described by suchterms as scratches,bubbles,dents,dings,bumps,blurs,smears,voids,pinholes,etc.These are highly subjective terms that defyprecise definition but which are nonetheless identifiable andmeasurable.2.1.2 color matchingprocedure by which a color is com-pared to a standard to determine if the two are visuallyindifferentiable under specified lighting conditions.2.1.3 continuous scanning motionviewing techniquewhereby the inspector views the whole specimen,in the timeallowed,without stopping in any one area of the panel.2.1.4 cosmetic flaws(or defects)see aesthetic qualities.2.1.5 footcandlesunit of illuminance equal to one lumenper square foot.2.1.6 membrane switcha momentary switching device inwhich at least one contact is on,or made of,a flexiblesubstrate.2.1.7 overlayouter layer of a membrane switch on whichthe graphics are printed.2.1.7.1 DiscussionNot all membrane switches have anoverlay.2.1.8 viewing anglethe angle between the line of sight ofthe observer and the surface of the specimen.2.1.9 window areasany area of a membrane switchthrough which a display,light,lamp,or other graphics,areviewed.3.Significance and Use3.1 This practice is designed to enable all manufacturers andusers of membrane switches to perform visual inspectionsunder uniform conditions.The aim is to eliminate key variablesin the inspection procedures so specimens can be viewed moreobjectively.3.2 Viewing specimens under these conditions could revealcosmetic defects in the specimen.Many of these defects orflaws are due to variables in the raw materials or the manu-facturing process.These cosmetic flaws or defects do notnecessarily mean that the specimen is defective.The determi-nation of whether a specimen is acceptable or defective varieswith the application and the needs of the user.Therefore,customer and vendor must agree on acceptable quality stan-dards prior to manufacturing.3.3 This practice does not establish standards for acceptabil-ity of specimens,only how they must be viewed(inspected).3.4 This practice is not intended to be used for colormatching purposes.Color matching must be performed undermore precise lighting conditions outside the scope of thispractice.4.Procedure4.1 Specimen shall be clean and dry.1This practice is under the jurisdiction of ASTM Committee F01 on Electronicsand is the direct responsibility of Subcommittee F01.18 on Membrane Switches.Current edition approved Feb.1,2012.Published February 2012.Originallyapproved in 95.Last previous edition approved in 2005 as F1595-00(2005).DOI:10.1520/F1595-00R12.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.2 Specimen shall be viewed by a person with normalvision(1 power)or corrected to normal vision(1 power).4.2.1 Corrective lenses must be un-tinted.Do not usenon-prescription or magnifying devices.4.3 Lighting source shall be cool white fluorescent tubesproducing 75 to 100 foot-candles at any point on the specimen.4.4 The inspection area shall have a neutral gray back-ground.Take care to keep the viewing area free from distrac-tions.4.5 View the specimen no closer than 18 in.from eye tosurface of the specimen.4.6 The viewing angle shall be perpendicular(plus or minus15)to the surface of the specimen.4.7 View the specimen in a continuous scanning motion toensure that the whole specimen is inspected.4.8 The maximum viewing time is dependent on the size ofthe specimen(see Table 1).4.9 View window areas against a diffused lighted back-ground