1、Designation:C1652/C1652M14Standard Test Method forMeasuring Optical Distortion in Flat Glass Products UsingDigital Photography of Grids1This standard is issued under the fixed designation C1652/C1652M;the number immediately following the designation indicates theyear of original adoption or,in the c
2、ase of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONTransmitted and reflected distortion in annealed,heat strengthened,and tempered glass can beme
3、asured by several methods.(1,2,3,4)2Qualitative methods are based on the observation ofwaviness in the glass as viewed in of reflected or transmitted images in a set of equidistant lines,calledZebra Lines.Quantitative measuring techniques are based on several methods,some of which are:(1)Measuring l
4、ocal curvature using mechanical radius gages(1,5,6,and Test Method C1651)(2)Moir Fringe analysis(7,8)(3)Double exposure of transmitted grid images(Practice F733)(4)Projection of an array of round dots(9)(5)Dual laser beams(10)The user should be familiar with techniques that are available so as to se
5、lect the most suitable afterconsidering the precision,speed,and test specification requirements.The test method described in thisdocument uses a digital camera to capture a transmitted or reflected image of a set of equidistant lines.Changes in the spacing of lines are used to quantifying the distor
6、tion.1.Scope1.1 This test method covers the determination of opticaldistortion of heat-strengthened and fully tempered architecturalglass substrates which have been processed in a heat controlledcontinuous or oscillating conveyance oven.See SpecificationsC1036 and C1048 for discussion of the charact
7、eristics of glassso processed.In this test method the reflected image ofprocessed glass is photographed and the photographic imageanalyzed to quantify the distortion due to surface waviness.The test method is also useful to quantify optical distortionobserved in transmitted light in laminated glass
8、assemblies.1.2 The values stated in either SI units or inch-pound unitsare regarded separately as standard.The values stated in eachsystem may not be exact equivalents;therefore,each systemshall be used independently of the other.Combining valuesfrom the two systems may result in nonconformance with
9、 thestandard.1.3 There is no known ISO equivalent to this standard.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 appli
10、ca-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3C162 Terminology of Glass and Glass ProductsC1036 Specification for Flat GlassC1048 Specification for Heat-Strengthened and Fully Tem-pered Flat GlassC1651 Test Method for Measurement of Roll Wave OpticalDisto
11、rtion in Heat-Treated Flat GlassF733 Practice for Optical Distortion and Deviation of Trans-parent Parts Using the Double-Exposure Method2.2 Other Standards:U.S.Patent 7 345 698 Optical System for Imaging Distor-tions in Moving Reflective Sheets(2003)1This test method is under the jurisdiction of AS
12、TM Committee C14 on Glassand Glass Products and is the direct responsibility of Subcommittee C14.11 onOptical Properties.Current edition approved May 1,2014.Published May 2014.Originallyapproved in 2006.Last previous edition approved in 2006 as C1652/C1652M 06.DOI:10.1520/C1652_C1652M-14.2The boldfa
13、ce numbers in parentheses refer to a list of references at the end ofthis standard.3For 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 on
14、the ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.Terminology3.1 See Terminology C162 of Glass and Glass Products.3.2 Definitions:3.2.1 focal length,FThe focal length of a specularreflector,due to the curvature at a point
15、 equals R/2.(See 3.2.3.)In transmitted light,local thickness changes introduce a con-vergence or divergence,equivalent to a lens with a focal lengthF.3.2.2 optical power,DThe optical power due to thecurvature at a point is D=1/F.The optical power is expressedin diopters,(Units 1/m),or as is typical,
16、in millidiopters.Theoptical power is also used to quantify optical distortion,thedeformation of images reflected from flat glass,or transmittedby laminated or bent glass,or both.3.2.3 radius of curvature,RThe local radius of curvatureat a point on the surface,in meters.Rxand Ryare respectivelymeasured in planes x(usually horizontal)and y(usuallyvertical).3.2.4 roll waveA repetitive,wave-like departure fromflatness in otherwise flat glass that results from heat-treatingthe glass in a horizontal c
