1、Designation: F2429 05 (Reapproved 2010)Standard Terminology Relating toAerospace Transparent Materials and Enclosures1This standard is issued under the fixed designation F2429; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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 These definitions cover generic optical terms whichappear in one of more standards relating to aerospace trans-p
3、arent materials and enclosures.1.2 The definitions cover, in most cases, special meaningsused in the transparency industry. No attempt has been made toinclude common meanings of the same terms as used outside ofthe transparency industry.1.3 Definitions included have, in general, been approved asstan
4、dard.2. Terminology2.1 Definitions:angular deviationthe angular displacement of a light rayfrom its original path caused by non-parallelism of oppositesurfaces as it passes through a transparent material, which isexpressed in units of angle (degree, minutes of arc, millira-dians) and is a function o
5、f the angle of incidence at eachsurface of the material and the index of refraction of thematerial.angular displacementthe angular separation of the second-ary image from the primary image as measured from thedesign eye position of a transparency.binocular disparitythe difference in angular deviatio
6、n be-tween two light rays passing through a transparency, origi-nating from two eye positions located 2.5 in. apart.birefringencethe separation of a light beam as it penetratesa doubly refracting material into two diverging beamscommonly known as ordinary and extraordinary beams,which may appear in
7、transparencies as rainbowing or theapparent random dispersion of light into its componentcolors.crazingthe occurrence of very small, localized, micro-cracksat or under the surface of, but not extending entirely through,a transparent material, which act like tiny mirrors that reflectlight in unwanted
8、 directions.design eyethe reference point in aircraft design from whichall visual or optical anthropometrical design considerationsare taken.distortionthe rate of change of angular deviation across thetransparency, usually characterized by grid-line slope, result-ing in the non-linear mapping of obj
9、ects viewed through thetransparency.grid line slopean optical distortion evaluation parameter thatcompares the slope of a deviated grid line to that of anon-deviated grid line, which is expressed as a ratio such as1 in 8 or 1 in 20 (the visual optical quality improves as thesecond number of the rati
10、o gets larger).halationthe scattering of light by the transparency into theviewers line-of-sight reducing the perceived contrast ofexternal objects, also referred to as haze.hazethe percent of transmitted light that is scattered so thatits direction deviates more than a specified angle from thedirec
11、tion of the incident beam, resulting in the reduction ofcontrast of objects viewed through the transparency.multiple imaging separationthe angular separation of pri-mary and secondary multiple images as measured from thedesign eye position.rainbowingcolored patterns in a transparency produced bythe
12、photo-elastic molecular nature of the material and stressgradients in the transparency in which certain angles andlight polarizations in relation to some windscreen designsmay produce localized bands of color in the transparency,often referred to as birefringence.scratchany marking or tearing of the
13、 surface in glass orplastic caused by an abrasive material.secondary imagethe image resulting from internal reflec-tions of light rays at the surfaces of the transparency.transmission coefficientthe ratio of the amount of radiantenergy leaving the last surface of an optical system to theamount of ra
14、diant energy incident on the first surface.1This terminology is under the jurisdiction of ASTM Committee F07 onAerospace and Aircraft and is the direct responsibility of Subcommittee F07.08 onTransparent Enclosures and Materials.Current edition approved May 1, 2010. Published June 2010. Originallyap
15、proved in 2005. Last previous edition approved in 2005 as F2429 - 05. DOI:10.1520/F2429-05R10.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.RELATED MATERIALASTM Test Method D1003 for Haze and Luminous Transmittance ofTransparent Pl
16、asticsASTM Test Method F1165 for Measuring Angular Displacement ofMultiple Images in Transparent PartsASTM Test Method F1316 for Measuring the Transmissivity of Trans-parent PartsASTM Test Method F2156 for Measuring Optical Distortion in Transpar-ent Parts Using Grid Line SlopeAL-TR-1993-0036, Defin
17、itions of Terms Relating to Aircraft Windscreens,Canopies, and Transparencies, Authored by Barbato, Maryann H.,Kama, William N., Task, Harry L., Hausmann, MarthaA., Bridenbaugh,John C., Logicon Technical Services, Inc.ASTM International takes no position respecting the validity of any patent rights
18、asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any tim
19、e by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will r
20、eceive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM I
21、nternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).F2429 05 (2010)2
